What is claimed is
1. In a mechanical press having a frame with a bed portion and a crown portion and a frame interconnecting said portions and a slide reciprocable in the space between said crown and bed portions; crankshaft means rotatably mounted in said crown portion, connecting rod means connected at one end to said crankshaft means, piston means connected at one end to the other end of said connecting rod means and at the other end to said slide, cylinder means parallel to the direction of movement of said slide including hydrostatic bearing means surrounding and slidably engaging said piston means for centering said piston means within said cylinder means.
2. A mechanical press according to claim 1 which includes journal portions on said crankshaft means, bearings in said crown portion engaging said journal portions, and hydrostatic bearing means interposed between said journal portions and said bearings.
3. In a mechanical press having a frame with a bed portion and a crown portion and a frame interconnecting said portions and a slide reciprocable in the space between said crown and bed portions; crankshaft means rotatably mounted in said crown portion, connecting rod means connected at one end to said crankshaft means, piston means connected at one end to the other end of said connecting rod means and at the other end to said slide, cylinder means parallel to the direction of movement of said slide surrounding and slidably engaging said piston means, said crankshaft means comprising a pair of parallel crankshafts, a gear on each crankshaft, said gears meshing and connecting said crankshafts for counterrotation, said connecting rod means comprising a connecting rod connected to each crankshaft, said piston means and cylinder means comprising a piston and cylinder for each connecting rod, and balancing means located on said crankshafts for substantially counterbalancing the mass of the slide and pistons and connecting rods.
4. A mechanical press according to claim 3 which includes air passage means in said crown portion, and means for blowing air through said air passage means.
5. A mechanical press according to claim 3 which includes passage means in said crown portion extending perpendicular to and around said cylinder means, a blower for supplying air to one end of said passage means.
6. A mechanical press according to claim 1 in which said cylinder means include annular regions at each end in continuous sliding engagement with said piston means, pockets formed in said regions and distributed circumferentially thereof, and means for supplying fluid at controlled pressure to said pockets.
7. A mechanical press according to claim 1 in which said crankshaft means comprises journal portions, bearings in said crown portion engaging said journal portions, pockets formed in said journal portions and distributed circumferentially thereof, and passage means in said crankshaft connected to said pockets for the supply thereto of fluid at controlled pressure.
8. In a mechanical press having a frame with a bed portion and a crown portion and a frame interconnecting said portions and a slide reciprocable in the space between said crown and bed portions; crankshaft means rotatably mounted in said crown portion, said crankshaft means adapted to reciprocate said slide, said crankshaft means including journal portions, bearings in said crown portion engaging said journal portions, pockets formed in said journal portions and distributed circumferentially thereof, and passage means including a flow restrictor disposed in each passage in said crankshaft connected to said pockets for the supply thereto of fluid at controlled pressure.
9. A mechanical press according to claim 8 in which crankshaft includes crankpin means engaging said connecting rod means, and further pockets formed in said crankpin means and connected to said passage means to receive fluid at controlled pressure therefrom.
10. A mechanical press according to claim 3 in which said balancing means comprises at least one eccentric mass on each crankshaft and eccentric mass incorporated in said gears.
11. A mechanical press according to claim 3 in which said gears are fixed to said crankshafts at one end thereof, a flywheel-clutch on the other end of one crankshaft adapted for being driven to supply power to said crankshafts, and brake means interposed between said frame and the other end of the other crankshaft selectively operable for braking said crankshafts to said frame.
12. A mechanical press according to claim 11 in which said brake means includes a disc fixed to said other end of said other crankshaft, and caliper brake means on said frame adjacent said disc.
13. A mechanical press according to claim 12 in which said caliper brake means include first caliper brake means operable into braking engagement with said disc by fluid pressure and second caliper brake means spring urged toward braking engagement with said disc and operable into retracted position by fluid pressure.
14. In a mechanical press having a frame with an adjustable bed portion and a crown portion and a frame interconnecting said portions and a slide reciprocable in the space between said crown and said bed portion, said bed portion being adjustable in a direction toward and away from said slide for providing the correct shut height for a die set, said bed member being mounted in the lower portion of said frame, first means adjustably supporting said bed member in the lower portion for movement of the bed member toward and away from the crown portion, fluid means in the lower portion for fixedly clamping said bed member in adjusted vertical position additional fluid means for fixedly clamping said bed member in a plane parallel to its surface, crankshaft means rotatably mounted in said crown portion, connecting rod means connected at one end to said crankshaft means, piston means connected at one end to the other end of said connecting rod means and at the other end to said slide, and cylinder means parallel to the direction of movement of said slide surrounding and slidably engaging said piston means.
15. A mechanical press according to claim 14 in which said first means include screw threaded means interposed between the underside of said bed member and the lower portion.
16. A mechanical press according to claim 14 in which said first means includes cylinder piston means above said bed member and connected between spaced points of said bed member and the press frame and operable in one condition of energization to exert upward force on said bed member and in another condition of energization to exert downward force on said bed member.
17. A mechanical press according to claim 14 in which said second means including V-shaped members on opposite sides of said bed member extending in a direction parallel to the direction of adjustability of the bed member, a first member fixed to the lower portion of the press frame at one side of the bed member complementary in shape to and engaging the adjacent V-shaped member, a second member movably mounted on the lower portion of the press frame at the other side of the bed member complementary in shape to and engaging the adjacent V-shaped member, and actuator means in said lower portion engaging said second member on the side facing away from the said bed member and operable by the supply of pressure fluid thereto to clamp said bed member to said lower portion.
18. In a press having spaced and fixedly interconnected crown and lower portions, a bed member, adjustable toward and away from said crown portion, means in said lower portion operable to clamp and locate said bed member therein, crankshaft means rotatable in said crown portion, piston means slidably guided in elongated cylinders in said crown portion for movement toward and away from said bed member, means operatively connecting said crankshaft means to said piston means, and a slide connected to said piston means at the end thereof nearest said bed member, said piston means forming the sole means supporting and guiding said slide in said press frame.
19. A press according to claim 18 in which said crown portion is a box-like member having a sealed compartment within which said crankshaft means is supported.
20. In a press having a press frame with spaced crown and lower portions, said frame having a front and a back and sides, a slide in the space between said crown and lower portions, a pair of parallel crankshafts rotatable in said crown portion and extending in the fore and aft direction therein, an elongated cylinder in the crown portion beneath the throw of each crankshaft, said cylinders being in parallel aligned relation in the side to side direction of said crown portion, a piston slidable in each cylinder and at the bottom fixed to said slide, said pistons and cylinders providing the sole support and guidance of said slide, and a connecting rod connected between the throw of each crankshaft and the upper end of the said piston therebeneath.
21. A press according to claim 20 which includes gears on one end of the crankshafts in direct meshing relation for synchronous rotation of the crankshafts in respective opposite directions.
22. A press according to claim 20 which includes counterweight means fixed to each crankshaft on the opposite side of the throw thereof from the end of the crankshaft on which a said gear is mounted, each said gear comprising eccentric mass having the same angular disposition about the axis of the crankshaft as said counterweight means.
23. In a press according to claim 20, said frame having lower portion at the bottom, base means beneath said lower portion to support the press frame on a floor surface, said base means having two spaced leg means at one side of the press and a single leg means at the other side of the press thereby providing substantially three point support for the press frame so that a portion of the press weight is supported on each leg irrespective of the waviness of the floor.
24. In a press frame; a press crown, spaced frame members extending from side to side of the press and engaging the underside of said crown at the front and back of the crown, each frame member being windowed to expose the space beneath said crown, base members extending in the fore and aft direction of the press frame and engaging the underside of said frame members at the ends thereof, and strain rods extending vertically through said crown and frame members and base member and fixedly interconnecting said crown and frame members and base members.
25. A press frame according to claim 24 which includes beam members extending in the fore and aft direction of the press frame at the sides of said frame members near the lower ends thereof and fixed to said frame members.
26. A press frame according to claim 25 which includes a bed member disposed in the space confined in the fore and aft direction by said frame members and in the side to side direction by said beam members.
27. A press frame according to claim 24 which includes means in said crown for rotatably supporting crankshafts therein extending in the fore and aft direction of the press frame, compartments recessed into the front and rear sides of the crown in which the ends of the crankshafts are disposed, and cover plates enclosing said compartments.
28. A press frame according to claim 24 in which one base member has a pair of dependent foot portions each at a respective end of the base member and the other base member has a single dependent foot portion near the middle of the length thereof.
29. A press frame according to claim 26 which includes bed member adjusting means interposed between said bed member and said base members.
30. A press frame according to claim 29 which includes reversible fluid actuators connected between the corners of said bed member and the underside of said crown.
31. A press frame according to claim 29 which includes clamping means carried by said bed member and said beam members operable for fixedly clamping said bed member in adjusted positions in said press frame.
32. In a crown for a press frame; a generally vertical body having body front and back faces and end faces and top and bottom faces, chambers recessed into said end faces and cover plates closing said chambers toward the outside, finned passage means extending laterally of said body and connected to said chambers near the bottoms thereof, a blower connected to one chamber near the top thereof, and an exhaust conduit connected to the other said chamber near the top.
33. A crown according to claim 32 which includes heat exchanger means in said one chamber through which air is blown by said blower.
34. A crown according to claim 32 in which said finned passage means are open at the front and back faces of said body, and further cover plates on the front and back faces of said body closing off said passage means from the atmosphere.
35. A crown according to claim 32 which includes means in said body defining vertical cylinders extending therein from said bottom face and passing through said finned passage means in substantial perpendicular relation thereto.
The present invention relates to mechanical presses and is particularly concerned with a mechanical press which operates at extremely high speed.
Mechanical presses are, of course, well known and consist of a frame with a crankshaft which is driven by a motor and to which crankshaft is connected a slide that reciprocates in the press to and from a bed member with parts of a die set being mounted on the slide and bed member for operating workpieces inserted therebetween as the slide reciprocates.
Mechanical presses are widely used for blanking and drawing operations and vary substantially in size and available tonnage and in the various accessories associated therewith.
It is usually the case that the slide in a mechanical press is connected to the crankshaft by a connecting rod which is adjustable in length or which is connected to another member that is adjustable in its relation to the slide so that the daylight opening between the slide and the bed can be adjusted to accommodate the press for various die sets. The slide is usually guided on the upright portions of the press frame extending between the head and bed so that the parts of the die set remain in accurate registration as the slide reciprocates.
The press according to the present invention is particularly characterized in being capable of extremely high speed operation, up to 1,600 strokes per minute or more of the press slide in a press rated at 60 tons or more. The press according to the present invention is, thus, particularly useful for blanking operations, such as for electric motor laminations and the like and, in contrast to high speed presses that are presently available, has a relatively long stroke and operates relatively large workpieces by virtue of the unique design of its bearings, reciprocating members, and stock feeding apparatus.
A particular object of the present invention is the provision of a mechanical press so constructed and arranged as to permit operation thereof within the range of speeds above referred to, namely, up to 1,600 strokes a minute or more.
Another object of the present invention is the provision of a slide construction and arrangement which permits high speed operation of the slide.
Still another object is the provision of a mechanical press especially constructed for high speed operation in which all of the relatively moving parts of the press are adequately lubricated at all times and wherein the undesirable heat developed from the high speed operation of the press rapidly conveyed from the bearings and dissipated.
Still another object of the present invention is the provision of a mechanical press in which the daylight opening of the press can be adjusted but in which the adjusting arrangement for this purpose is separated from the slide of the press so as not to add any additional weight thereto.
Still another object of the present invention is the provision of a novel guide arrangement for guiding the slide of a mechanical press.
Still another object of the present invention is the provision of a mechanical press in which dual counterrotating crankshafts are employed for actuating the press slide with a dynamic balancing arrangement provided for inhibiting vibration of the press at high speed.
These and other objects and advantages of the present invention will become more apparent upon reference to the following detailed specification taken in connection with the accompanying drawings in which:
FIG. 1 is an exploded perspective view of the press frame.
FIG. 2 shows a stock supply and a straightening roll stand through which the stock is fed toward the press and also shows the extreme left end of a stock loop control device.
FIG. 3 is a perspective view showing a press according to the present invention and showing the right end of the stock loop control device referred to in respect of FIG. 2.
FIG. 4 is a view partly in section showing the head of the press and looking in at the press in the same direction as in FIG. 3.
FIG. 5 is a view like FIG. 4 but looking in at the head of the press from the rear of FIG. 3 and with the cover plate removed from the press head to expose the parts therein.
FIG. 6 is a somewhat schematic plan sectional view indicated by line 6-6 on FIG. 4 and showing passages for cooling air provided in the press head.
FIG. 7 is a fragmentary vertical sectional view through one of the crankshafts of the press and is indicated by line 7-7 on FIG. 4.
FIG. 8 is a somewhat schematic vertical sectional view indicated substantially by line 8-8 on FIG. 7.
FIG. 9 is a sectional view indicated by line 9-9 on FIG. 8.
FIG. 10 is a fragmentary perspective view showing the manner in which hydrostatic bearing pockets are formed in the sleeve member illustrated in FIG. 9.
FIGS. 11A and 11B are somewhat schematic views showing the manner in which hydrostatic bearing pockets are formed in the crankshafts.
FIG. 12 is a section on line 12-12 of FIG. 11.
FIG. 13 is a section on line 13-13 of FIG. 11.
FIG. 14 is a sectional view indicated by line 13-13 on FIG. 11 showing a groove establishing a hydrostatic thrust bearing for the crankshaft.
FIG. 15 shows a typical flow restrictor which is disposed at the entrance of each hydrostatic bearing pocket to control the oil flow thereto.
FIG. 16 is a perspective view illustrating the manner in which the bed member that receives the stationary portion of the die set is adjustably mounted in the press.
FIG. 17 is a sectional view indicated by line 17-17 on FIG. 16 showing a fluid actuator connected with the adjustable bed member to assist in the elevation thereof and to clamp the bed member in adjusted positions.
FIG. 18 is a sectional view indicated by line 18-18 on FIG. 16 showing one of the adjusting devices for adjusting the bed member in the press frame.
FIG. 19 is a fragmentary plan sectional view looking down on top of the bed member and showing the manner in which it is clamped in the press frame in adjusted positions.
FIG. 20 is a fragmentary perspective view showing the fluid actuators which clamp the adjustable bed member in the press frame.
FIG. 21 is a schematic view showing the straightening roll stand and the drive thereto and the loop control device to which the straightening roll stand feeds the stock being operated.
FIG. 22 schematically illustrates the control pulses developed for controlling the speed of operation of the straightening roll stand.
FIG. 23 schematically illustrates the hydraulic circuit of a stock feed arrangement interposed between the loop control device and the die set in the press for feeding stock into the die set.
FIG. 24 is a vertical sectional view through the feed device.
FIG. 25 is a plan section indicated by section line 25-25 on FIG. 24 showing an intermittent feed arrangement for intermittently driving the feed rolls of the feed device.
FIG. 26 is a section indicated by line 26-26 on FIG. 25 showing more in detail the intermittent feed and an arrangement for eliminating lost motion therein.
FIG. 27 is a schematic representation of the hydraulic control circuit employed with the press.
BRIEF SUMMARY OF THE INVENTION
A mechanical press according to the present invention has a press frame consisting of a bed portion and a sealed crown portion and uprights extending therebetween with prestressing strain rods interconnecting the crown portion and bed portion.
Within the crown portion is rotatably mounted a pair of counterrotating crankshafts, each having a throw thereon to which one end of a connecting rod is connected. Each connecting rod at the other end is connected with one end of a piston member with the other end of each piston member being connected to the press slide that is disposed beneath the crown portion of the press frame.
The press crown includes cylinders which are open at both ends and in which the aforementioned pistons are slidably guided. Balancing weights mounted on the crankshaft substantially counterbalance the slide and pistons and connecting rods so that the press will operate at high speed without any substantial amount of vibration.
The aforementioned crankshafts are geared together at one end and the other end of the crankshafts is connected to a flywheel through a pneumatically operated clutch. The flywheel is belt-driven from a drive motor that may be variable in speed or which may have a variable speed output shaft which is drivingly connected with the motor by way of an eddy-current clutch.
The other crankshaft has a brake disc mounted thereon adjacent the aforementioned clutch and flywheel for braking the crankshaft to a halt when necessary. When the aforementioned clutch disengages the crankshaft from the flywheel the minimum amount of energy is presented to the brake which must bring the crankshafts and the parts connected thereto to a halt.
The flywheel also has a brake associated therewith which is not, however, employed during normal press operations, but is merely used during set up and to bring the flywheel quickly to a halt when necessary.
The bed portion of the press has a vertically adjustable bed member therein so that the daylight opening of the press can be adjusted without providing adjustable members associated with the connecting rods and which would add to the reciprocating mass.
The adjustable bed member is adapted for being elevated and lowered by screw jacks disposed therebeneath and is clamped fixedly in position by fluid actuators engaging the bed member from above and which fluid actuators are also employed to carry the weight of the bed member during vertical adjustment thereof.
The press is arranged to operate at extremely high speed, up to 1,600 strokes per minute or more, and an arrangement for feeding strip stock to the press is provided which will feed efficiently at the operating speeds referred to.
The stock supply is preferably in the form of a roll, or reel, of strip stock rotatably supported and a drag brake is provided to maintain tension on the stock and to prevent the stock reel from running ahead when the press is stopped. The stock from the stock reel leads to a straightening roller stand which is driven at variable speed as by way of an eddy current clutch. The stock, upon leaving the straightening roll stand, passes through an enclosure which guides the stock and within which the stock is thrown into somewhat of an S-shaped loop.
Within the enclosure, detectors are provided which detect maximum and minimum lengths of the loop therein. When a maximum length is detected, the speed of the straightening roller stand is reduced and when a minimum loop is detected the press and the straightening roller stand are halted. The straightening roller stand is arranged to feed a slight excess amount over the feed required by the press on each stroke, so that the maximum loop detector, in normal operation, will periodically reduce the feed from the straightening roller stand.
Between the straightening roller stand and the press is a feed arrangement consisting of opposed rollers which bear on the stock from opposite sides and one of which is intermittently driven so as to advance stock into the die set in the press while the die set is open. The feed device includes an arrangement for eliminating lost motion in the drive to the feed rolls so that the feed into the die set in the press is quite rapid and without hesitation and is substantially positive. The feed device comprises an arrangement for separating the rolls under emergency conditions and also when the rotation of the driven one of the rollers is interrupted.
Due to the high speed of operation of the press, it is preferable for the relatively moving parts continuously to be bathed in lubricant and, to this end, portions of the device according to the present invention are closed to form oil compartments. Also, due to the high speed of operation of the press, heat can be developed, particularly in the press crown, and the press crown is provided with cooling passages through which cooling air is blown with the cooling air passing through an oil cooler before it is blown through the passages in the crown.
In order to reduce friction to a minimum and to maintain good guiding and journaling conditions, particularly for the rapid moving parts of the press, the crankshaft and the connecting rods and the pistons connected to the slide are provided with hydrostatic bearing arrangements to which lubricating fluid is continuously supplied at controlled pressure.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawings more in detail, the press frame has a crown portion 50 and a lower frame portion 48 and uprights 52 therebetween. The lower frame portion 48 of the press frame and the uprights 52 may be combined in the form of integral frame members 53 in front and 55 in back, each having a window 600 therein. Frame member 53 engages the underneath side of the crown 50 at thr front of the press and frame member 55 engages the underneath side of the crown 50 at the back of the press. Leg members 54 and 56 extend in the fore and aft direction of the press beneath the lower ends of the above mentioned frame members 53 and 55 and at the opposite sides of the frame members are the bed clamp beam members 602 extending in the fore and aft direction of the press.
The crown and frame members and leg members are fixedly interconnected by prestressed strain rods 47 extending vertically therethrough and disposed near the corners of the crown portion 50 of the press frame. Nuts 59 are threaded on the ends of rods 57.
The bed clamp beam members 602 are bolted to the frame members 53 and 55 and the frame members together with the above mentioned bed clamp beam members define the space in which the bed member of the press, indicated at 46, is disposed for vertical adjustability.
In FIG. 2, numeral 30 generally designates a stock supply which may take the form of a reel of strip stock 32 mounted on a rotary support with the support preferably including a drag brake to stabilize rotation of the reel. From the stock supply, stock 32 is delivered to a straightening roller stand generally designated at 34 and which is substantially conventional except for the drive thereto which will be discussed more fully hereinafter.
Within the straightening roller stand, the stock passes through spaced sets of feed rollers which advance the stock in the direction of its length and interposed between the feed rollers are a plurality of straightening rollers in opposed rows and staggered relation so that the stock is straightened as it passes through the straightening roller stand. From the straightening roller stand, the stock enters a stock loop control device generally indicated at 36 and also to be discussed more fully hereinafter.
In brief, within the stock control device, the strip of stock is thrown into a generally S-shaped curve and within the stock control device are instrumentalities for detecting a predetermined maximum length of the loop and a predetermined minimum length thereof. The straightening roller stand is arranged to feed stock at a slightly higher speed than it is consumed in the press so that, under normal circumstances, the stock loop gradually lengthens until a detector in the device detects a maximum loop length whereupon the speed of feeding stock through the straightening roller stand is reduced to reduce the length of the loop and normal feeding operations then continue. When a minimum stock loop is detected, a situation that should not occur in normal operation, the operation of the press and the straightening roller stand is stopped.
FIG. 3 will show that the loop detecting device is connected to supply the stock to a feed device generally indicated at 38 and which feeds the stock into the press. Device 38 feeds the stock intermittently, interrupting the feed during the working stroke of the press when the die set therein closes and feeding stock when the die set is open. The strip of stock being fed into the press is confined from above, as by a plate 40, and under emergency conditions when the stock jams or the feeding thereof into the die set is otherwise interrupted, the stock will buckle downwardly and actuate a switch which will interrupt the feeding of the stock and stop the press.
Within the press is a die set consisting of an upper part 42 and a lower part 44. Lower part 44 is mounted on a bolster 45 supported on a bed member 46 which is vertically adjustable between the lower bed portions of the front and rear press frame members 53 and 55. The press frame includes crown portion 50, front and rear press frame members 53 and 55 with lower portion 48 integral with vertical portions 52 extending between the crown portion and the legs 54 and 56.
The press frame is supported on a leg 54 having two feet at one side of the press and leg 56 having one foot at the other side so that the press can be more easily mounted on a nonuniform surface.
The upper portion 42 of the die set is mounted on a slide 58 that is driven in reciprocation in the space between crown portion 50 and bed portion 46 by crankshaft means rotatably mounted in the crown portion. The crankshaft means receives power from a drive motor 60 which is either variable in speed or which drives the crankshaft means through an eddy current clutch so that the speed of the crankshaft means can be controlled.
The press according to the present invention is adapted to operate at extremely high speeds, up to 1,600 strokes per minute or more, and considerable heat may be developed in at least the crown portion of the press frame. To carry the thus developed heat away, there is mounted on the crown a blower 62 having a drive motor 64 and which blower blows air through passages provided in the crown portion of the press frame and out the stack 66. As will be seen hereinafter, the air is blown through a heat exchange interposed between blower 62 and the air passages in the crown portion of the press.
The skeleton of the stock fed out of the die set passes through a scrap cutter 68 arranged at the side of the press opposite the feed device 38 so that the skeleton of stock is clipped into small pieces as it emerges from the press so that it is in ideal form for disposal as scrap.
The entire operation of the press may be controlled from a console 70 suitably positioned adjacent the press and connected by cable means with a relay panel 72.
The above mentioned crankshaft means mounted in the press crown comprise a pair of counterrotating crankshafts (FIG. 4) which extend in the fore and aft direction of the press crown, namely, in a direction at right angles to the direction of stock fed through the press, which is considered from side to side.
FIG. 4 shows at somewhat enlarged scale the crown of the press looking in the same direction as in FIG. 3 but with portions of the crown cut away to show the interior thereof. In FIG. 4, the crankshafts of the press are seen from one end and are indicated at 74 and 76. The crankshafts, on the ends visible in FIG. 4, carry gears 78 and 80, respectively, which mesh and which cause counterrotation of the crankshafts in synchronism. Gears 78 and 80 are disposed in a recessed compartment 82 in the crown portion 50 of the press and which is normally closed by a cover plate 84. The gears have holes 79 and 81 therein for counterbalancing purposes to be explained more fully hereinafter.
FIG. 4 also shows blower 62 and drive motor 64 therefor and, in FIG. 4, it will be seen that the blower 62 has an inlet 86 and an outlet discharging through a port 88 in the crown portion of the press into a substantially vertically disposed chamber 90 formed in the crown portion of the press at the same side as the blower 62. Mounted in chamber 90 near the upper part thereof is a heat exchanger 92 of any suitable type and through which lubricating oil is moved in order to be cooled by the air blown into chamber 90 by blower 62.
In the lower part of crown portion 50 there is provided a plurality of laterally extending channels or passages 94 which, at one end, communicate with the bottom of chamber 90 and at the other end communicate with the bottom of chamber 96 on the opposite side of the crown portion of the press from chamber 90. Chamber 96 extends vertically in the crown portion of the press and terminates in a port 98 communicating with the aforementioned exhaust stack 66.
As will be seen in FIG. 6, the passages or channels 94 are defined by horizontal fins 100 integral with the press crown and projecting laterally from a central portion of the press crown in which is formed a pair of bores 102 for a purpose to be explained hereinafter. The channels or passage means 94 have ports 104 at one end communicating with chamber 90 and ports 106 at the other end communicating with chamber 96.
FIG. 5 is a view looking at the crown portion 50 of the press from the end opposite the end illustrated in FIGS. 3 and 4.
In FIG. 5, the ends of crankshafts 74 and 76 opposite those seen in FIG. 4 are shown. Crankshaft 76 will be seen to be the input crankshaft and has mounted thereon a flywheel-clutch unit 108. This unit is driven by belt 110 which leads upwardly to the top of the crown portion of the press to be drivingly engaged by the output member of drive motor 60.
The flywheel-clutch 108 is of a substantially conventional type and has a flywheel portion which normally continuously rotates and which embodies a pneumatically operated clutch between the flywheel and crankshaft 76. The clutch is normally disengaged so that the flywheel turns freely on crankshaft 76, but upon the supply of pressure fluid to the clutch, the clutch will engage and drivingly connect flywheel-clutch 108 with crankshaft 76. The supply of pressure fluid to the clutch can be accomplished by way of a conduit 112 which is connected with a passage in crankshaft 76 by way of a rotary coupling.
It is advantageous to provide a fluid operated brake 114 adjacent the flywheel which can be adjusted into braking engagement with the flywheel when it is desired to bring the flywheel to a halt.
The end of crankshaft 74 seen in FIG. 5 carries a brake disc 116. The marginal portion of brake disc 116 is disposed between first caliper brakes 118 and 120 and second caliper brakes 122. Caliper brakes 118 and 120 are normally spring urged out of engagement with disc 116 and are moveable into braking engagement with the disc by a supply of pressure fluid thereto via conduits 123 and 124.
Caliper brake 122, on the other hand, is spring urged toward braking engagement with disc 116 and is held out of engagement with the said disc by a supply of pressure fluid thereto via a conduit 126. During normal operation of the press, caliper brake 122 is always disengaged but, upon loss of fluid pressure in the system, this brake will engage and prevent operation of the press.
Caliper brakes 118 and 120, on the other hand, work in unison and are normally employed when it is desired to stop the crankshafts as, for example, during set up operations and the like.
Crankshaft 74 at the end adjacent brake disc 116 carries a cog pulley 128 about which is entrained a cog belt 130 which leads downwardly at an angle away from the press crown and is operable for driving the feed device 38.
Flywheel-clutch 108 and brake disc 116 and pulley 128 are disposed in a compartment 132 recessed into the respective end of the crown portion of the press and which is normally closed by a cover plate 134, most of which is broken away in FIG. 5 to show the elements in the compartment.
FIG. 7 is a longitudinal section taken along the axis of crankshaft 74 and showing that the crankshaft is supported in crown portion 50 of the press frame by bearing housings 150 and 152 mounted in webs 154 and 156 provided therefor in crown portion 50 of the press. Each of bearing housings 150 and 152 preferably has a sleeve type bushing 158, 160 therein. The bearing housings 150 and 152 are disposed on opposite sides of the throw of the crankshaft and which throw is connected to the upper end of a connecting rod 162.
On the opposite side of bearing housing 152 from connecting rod 162 is a counter weight member 164, the center of gravity of which is disposed in the opposite radial direction from the axis of rotation of the crankshaft from that of the throw to which connecting rod 162 is connected. To produce a corresponding dynamic balancing effect at the opposite end of crankshaft 74, gear 78 has holes 79 located so that the heavy side of gear 78 opposite the holes produces the required balancing force.
In connection with the dynamic balancing of the crankshafts and slide assembly it will be noted that the gears 78 and 80 on the crankshafts 74 and 76, which are in mesh to produce counterrotation of the crankshafts, are massive and that holes 79 and 81 are drilled therein on the same side as the throw of the respective crankshaft. Each gear thus has eccentric mass on the side of the respective crankshaft opposite the throw of the crankshaft and on the same side as the aforementioned counter weights 164 mounted on the respective crankshafts. Furthermore, the eccentric mass of the gear and the mass of the counter weight are disposed on opposite axial sides of the throw of the respective crankshaft.
The brake disc 116, previously referred to, has a relatively large hub portion 166 which is tightly fitted on a tapered region of the crankshaft and clamped in place by a nut 168.
The extreme end of crankshaft 74, on the opposite side of pulley 128 from disc 116 is supported in a bearing 170.
FIG. 7 also shows the caliper brakes 118 and 120, both of which will be seen to be fixed to crown portion 50 of the press frame end to comprise elements in opposed relation on opposed sides of the disk 116.
The crankshaft 76 is constructed identically with crankshaft 74 except that, in place of the brake disc 116 and pulley 128 in compartment 132, crankshaft 76 carries the aforementioned flywheel-clutch 108.
The lower end of connecting rod 162 engages a pin 180 which is fitted in a bore 181 in the upper end of a piston 182 and is held in place in the bore by a plate 184 connected with the piston by a screw 186.
The arrangement of the connecting rods and pistons pertaining to the crankshafts is better illustrated in FIG. 8. In FIG. 8, which is a view looking in at the crankshafts in the same direction as in FIG. 4, it will be seen that the throw of crankshaft 74 to which connecting rod 162 is connected is indicated at 188, whereas crankshaft 76 has a throw 190 to which its connecting rod 192 is connected. The lower end of connecting rod 192 is connected with a respective piston 194 by means of a pin 196. Each of the pistons 182 and 194 extend downwardly to slide 58 and are fixed thereto as by bolts 198. It will be noted that slide 58 is relatively small and, therefore, relatively light and is guided solely by pistons 182 and 194 which are, in turn, guided in cylinders 200 and 202, respectively, and which are fixed in crown portion 50 of the press frame.
The pistons 182 and 194 are, in turn, guided in respective cylinders 200 and 202 which are fixedly mounted in crown portion 50 of the press frame in the aforementioned bores 102.
Each of the cylinders 200 and 202 is preferably flanged at the bottom as at 204 and 206 so as to abut the bottom of the crown portion of the press.
Each of the cylinders 200 and 202 has an upper annular region 208 and a lower annular region 210 and each of which regions serves as a bearing surface to guide the respective one of the pistons 182, 194 as the pistons undergo reciprocating motion along the axes of cylinders 200 and 202.
Between the aforementioned annular regions, each cylinder has space 212 which serves as a lubricant drainage area to collect oil escaping from annular regions 208 and 210.
Each of the regions 208 and 210 of each of the cylinders is provided with circumferentially spaced pockets 214 in region 208 and 216 in region 210. These pockets are spaced circumferentially about the respective piston as will be seen in FIG. 9 and are provided to establish hydrostatic bearing means between the cylinders and pistons for guiding the pistons in the cylinders as accurately as possible and in as nearly a friction free manner as possible.
Each pocket may be formed by an arcuate recess formed into the inner surface of the respective cylinder as shown in FIG. 10.
The pockets 214 and 216 are interconnected by axial passages 218 formed in the respective cylinder and having branches 220 leading to the respective pockets. The upper ends of the said axial passages 218 are interconnected by an annular passage 222 formed in the upper end of the respective cylinder and closed on top by a cover plate 224. At one point about the respective cylinder, a supply conduit 226 is connected with the respective annular passage 222 by drilled passages 228.
The supply via conduit 226 may be on the order of about 400 pounds per square inch and adjacent the point of supply of the pressure fluid to each of the said pockets there is preferably a flow restrictor element 230, a representative one of which is schematically illustrated in FIG. 15 adjacent a typical pocket 214.
The crankshafts are also provided with hydrostatic bearings and crankshaft 74 is shown somewhat in detail in FIGS. 11A, 11B, 12 and 13. Crankshaft 76 is provided with hydrostatic bearings in the same manner as crankshaft 74.
In FIGS. 11A and 11B, it will be noted that crankshaft 74 is provided with journal portions 240 which rotate in bushings 158, 160 mounted in bearing housings 150, 152 carried in crown portion 50 of the press frame. Each bushing, on the end facing the throw 188 of the crankshaft, has a radial flange 244.
Each of the aforementioned journal portions of crankshaft 74 is provided with three flats 246 distributed uniformly thereabout in a circumferential direction as shown in FIG. 13 and forming pockets for receiving pressure fluid to form hydrostatic bearing means for the journal portions.
The pressure fluid is supplied from a conduit 248 via a rotary fitting 250 to a drilled passage 252 in the crankshaft which is connected by radial passages 254 with the aforementioned pockets 246.
The throw 188 of the crankshaft is provided with four flats 258 distributed as shown in FIG. 12 and each flat forming a pocket for receiving fluid under pressure from passage 252. Radial passages 260 and 262 connect the pockets 258 with the passage 252. Radial passage 262 also connects passage 252 with an axial passage 264 connecting at its opposite ends with annular grooves 266 formed in flanges 268 formed on the crankshaft at opposite ends of throw 188.
The exit ends of passage 264 and of passages 254 and 260 are all provided with restrictors of the type shown in FIG. 15 to control the rate of fluid flow into the several pockets.
Connecting rod 162 has a longitudinal passage 270 through which lubricant is conducted to the bearing in which the pin connecting the connecting rod with the pertaining piston is mounted.
Each of the pockets 246 and 258 is advantageously about an inch wide and 31/4 inches long, although the specific size of each pocket is subject to considerable variation.
Pockets 246, as mentioned, are uniformly distributed about the journal portions 240, whereas pockets 258 are arranged so that in the position in which throw 188 is shown in FIG. 11B, namely, at its lowermost position, there is a pocket 258, 30° above the horizontal central plane of the throw on each side of the throw and another pair of the pockets similarly disposed 30° below the said plane. The disposition of the pockets on the throw will be seen in FIG. 12.
FIGS. 16 through 20 illustrate the adjustable bed member 46 and the arrangement for adjusting the bed member and for clamping it between the opposed bed clamping beams 602 and downward against the two adjusting mechanisms including adjusting screws 286 and nuts 288. Thus all clearance in the vertical guiding members 312, 314 and 316 and in the adjusting screw and nut assemblies is effectively eliminated.
Connected to the corners of bed member 46 are piston rods 282 extending upwardly into cylinders 284 which, at the upper ends, are fixed to the press frame. Pistons in cylinders 284 are connected to rods 282 and can be reversibly supplied with fluid pressure either to press rods 282 downwardly or to lift the rods upwardly.
Beneath bed member 46 is located a pair of spaced screw elements 286 fixed to the underside of the bed member and each threadedly engaging a respective nut 288, each of which has connected thereto a wormwheel 290 engaged by a respective worm 292. The nuts and wormwheels and worms are confined in frames on housings 294 which, at the bottom, are fixed to leg portions 54 and 56 of the press frame. The threads 296 formed on the nut and screw are preferably buttress type threads in order better to carry the stamping impact loads developed during operation of the press.
Each of worms 292 has a shaft 298 connected by bevel gearing 300 with a transverse shaft 302 forming the output member of a geared head speed reducing motor 304. Geared to shaft 302 by gearing 306 is a counter 308, the count on which will indicate the shut height of the press. Connected to be driven in unison with counter 308 is a selsyn transmitter 310 which is in circuit with a selsyn receiver on the control console so that a remote indication of the shut height of the press will also be provided.
To adjust the bed member vertically, cylinders 284 have fluid supplied thereto to urge rods 282 vertically by a force sufficient to lift the dead weight of bed 46 together with bolster 45 and lower die section 44, and the nuts 288 can then be rotated to move the bed member in the desired direction. When the adjusting motion is completed, the nuts are halted and the cylinders 284 are supplied with fluid in a direction to thrust rods 282 downwardly thereby clamping bed member 46 in position.
The bed member 46 is provided on each side with a V-shaped element 312 (FIG. 19) extending vertically along the bed member. At one side of the press element 312 engages a complementarily shaped element 314 fixed to the bed clamp beam 602 of the press frame. On the opposite side, another element 316 engages the adjacent element 312 and is, in turn, engaged on the side opposite element 312 by fluid piston means 318. Fluid piston means 318 are adapted for receiving pressure fluid via conduit means 320.
When pressure is relieved from the pistons 318, the bed member 46 can be moved vertically in the press frame, but when the pistons 318 are supplied with pressure, the bed member 46 is fixedly clamped in the press frame and is, at the same time, accurately located therein.
FIG. 21 shows the straightening roll stand 34 and the loop control device 36 somewhat more in detail. The straightening roll device comprises feed roller means 400 at opposite ends and interposed therebetween the staggered rows of straightening rollers 402. A chain 404 drivingly engages at least the feed rollers and is entrained about a sprocket 406 mounted on a shaft 408 which also carries a drive member 410 about which is entrained a drive element 412 leading to the output member 414 of a drive motor 416. Interposed between motor 416 and output member 414 is an eddy current clutch 418 which is operable to vary the coupling between the motor 416 and the output member 414.
Shaft 408 also carries a drive member 420 about which is entrained drive element 422 leading to and entrained about input element 424 of a pulse generator 426.
Turning now to the loop control device, it will be noted that the strip 32 being operated enters the device over a curved plate 430 into a space 432 which is bounded on the other side by another curved plate 434. Near the bottom of the loop control device another curved plate 436 guides the strip toward the exit opening 438 and into a pair of feed rollers to be described hereinafter.
The length of the loop of strip 32 disposed between curved plates 430 and 434 can be detected by a pair of lamp and photocell devices 440 and 442 or can be detected by proximity detectors or by mechanical switches which are actually engaged by the loop.
The straightening roller stand is arranged to drive the strip 32 at a speed slightly greater than the strip is consumed in the press so that the loop formed in the strip, indicated at 444 in FIG. 21, gradually lengthens until the light beam pertaining to the light and photocell set 442 is interrupted, whereupon the rate of feed by the straightening stand is reduced, whereupon the loop again gradually lengthens to the maximum length. Whenever the light beam pertaining to the lamp-photocell set 440 is established by shortening of the loop, the press and the straightening roller stand immediately halt.
The circuit for accomplishing adjustment of the speed of the straightening roller stand is schematically illustrated in FIG. 21 and comprises an input gate 450 having manual adjusting means 452 connected therewith and forming a switch for feed length command. The gate receives pulses from a crankshaft operated limit switch 454 which is actuated once for each revolution of the crankshafts.
Gate 450 supplies an output signal to a register 456 which receives pulses from pulse generator 426 via a wire 458. Register 456 is also adapted to receive a signal from the lamp-photocell set 442 via a wire 460. The output signal from register 456 is supplied to a digital-analog convertor 462 and the signal from this convertor is supplied to a clutch speed control component 464. Component 464 also receives a signal from a clutch tachometer 466 associated with drive motor 416 and eddy current clutch 418. This last mentioned signal is delivered to component 464 via wire 468.
The output signal from component 464 is conducted via wire 470 to a clutch control winding 472 which varies the coupling of motor 416 with output member 414.
In the operation of the loop control device, the current supply to the eddy current clutch which supplies power to the straightening roller stand is adjusted as shown in FIG. 22. In FIG. 22, the graph line indicates the current supply to the eddy current clutch and at the left end of the graph starting conditions are indicated, and wherein it will be seen that the average current supply of the eddy current clutch increases in steps, each step occurring at the moment a signal is supplied from the crankshaft limit switch to gate 450.
When the feed rate of the straightening roller stand is just slightly greater than the rate at which stock is fed into the press by the feed device, the clutch tachometer 466 supplies signals to register 456 so that the average current to the eddy current clutch remains at about the same average value. However, upon the loop and the loop control device reaching a length wherein the light beam in the lamp-photocell set 432 is interrupted, the signal from wire 460 to register 456 causes a sudden drop in the current to the eddy current clutch with, of course, a retardation in the feeding of the strip 32 from the straightening roller stand toward the loop control device.
The retardation in the feed continues until the interrupted light beam is again established, whereupon standard operating conditions are resumed, and the loop in the stock will again gradually increase in length up to the point that the aforementioned light beam is again interrupted.
The lamp-photocell set 440 takes no part in adjusting the current supply to the eddy current clutch but rather, when established by shortening of the loop in the stock, operates substantially immediately to halt the straightening roller stand and to unclutch the press from the drive motor and to energize the caliper brakes associated with the brake disc on crankshaft 74.
FIGS. 23 to 27 illustrate the feed device 38 somewhat in detail.
As will be seen in these figures, the feed device comprises an upper roller 550 which is intermittently driven in rotation. This roller rests on top of the strip of stock 32 being fed into the press. Another roller 502 engages the stock from beneath. Roller 502 is connected to a double acting piston 504 mounted in a cylinder 506. The underneath side of piston 504 is supplied with fluid from a conduit 508 which is maintained at about 150 to 300 pounds per square inch from a 400 pounds per square inch supply conduit 510 (FIG. 23) and a pressure regulating valve 512.
The upper side of piston 504 is connected to a conduit 514 that leads to one port of a reversing valve 516 which has a blocked center position and which can be moved into opposite end positions either to pressurize or to exhaust conduit 514. Fluid at about 1,000 pounds per square inch is supplied to the reversing valve 516 from conduit 518.
It will be apparent that the piston 504 can be caused to move downwardly any time valve 516 is shifted to its left-hand position and will move completely upwardly until roller 502 is stopped when shifted to its righthand position, whereas in the center position, fluid is trapped in cylinder 506 above piston 504.
Conduit 514 is connected by a branch line 520 with the downstream side of a check valve 522, the inlet of which is connected via a restrictor 524 with conduit 508.
Conduit 520 also leads into the upper end of a cylinder 526 in which is mounted a piston 528 connected to a roller 530 which, as will be seen hereinafter, is engaged by a cam which causes upward movement of piston 528 in cylinder 526 during each feed cycle of the feed device. When the piston 528 is moved upwardly in its cylinder and valve 516 is in its normally center blocked position, piston 504 will be moved downwardly in its cylinder 506 and thereby separate roller 502 from stock 32 and driven feed roll 500.
The physical construction of the said device is more fully illustrated in FIGS. 24 to 26. In these Figures, it will be noted that the device comprises a frame 550 in which is rotatably mounted an input shaft 552 to which is connected a pulley 554 about which is entrained the aforementioned cog belt 130 which is driven by pulley 128 mounted on crankshaft 74. Shaft 552 carries a cam 556 which engages roller 530 previously referred to and which is connected to piston 528 in cylinder 526.
It will be apparent that cam 556 actuates roller 530 to displace piston 528 upwardly in cylinder 526 during each dwell period of the feed rollers. This upward movement of piston 528 moves feed roller 502 downwardly and releases the stock from beneath feed rollers 500, 502 so that the stock is not constrained during the working cycle of the press.
Shaft 552 also carries the input elements 558 of an intermittent drive and which input elements cooperate with output elements 560 mounted on a shaft 562. Shaft 562 is journaled in portions 564 and 565 of housing 550 with portions 564 and 565 being connected to the main part of the housing by a web 566. The purpose of this is to permit screws 568 threaded into housing 550 to be adjusted to abutting relation with portions 564 and 565 and move the said portions to eliminate all lost motion between the elements of the intermittent drive. The resilience of the web 566 permits the aforementioned adjustment.
Shaft 562 on which the output elements of the intermittent drive are mounted carries a gear 570 meshing with a smaller gear 572 fixed to shaft 574 on which the upper feed roller 500 is mounted.
The last mentioned gears 570 and 572 are disposed in a closed compartment 576 through which lubricant can be flowed to maintain the gears lubricated at all times.
The piston 504 connected with lower roller 502 of the feed rolls will be seen in FIG. 24 to comprise an outer piston part 578 while slidably mounted therein is another piston part 580 with a compression spring 582 being provided between the upper end of piston 580 and the bottom of a bore in piston 578 in which piston 580 is mounted.
Conduit 508, previously referred to, is connected to the undersides of both of the said pistons, whereas conduit 514, previously referred to, is connected to supply fluid to the upper side of piston 504.
As will be seen in FIG. 25, portion 564 yieldably supported in housing 550 has a corresponding portion 565 spaced therefrom along shaft 562 so that two points of adjustment are provided for eliminating lost motion in the intermittent drive mechanism. Each of the portions 564 and 565 has a respective adjusting screw device 568 threaded in housing 550 and abutting the respective portion.
FIG. 27 schematically illustrates the hydraulic circuit pertaining to the press of the present invention.
The hydraulic circuit comprises a pair of pumps 601 and 603 driven by a drive motor 604 and supplying fluid to respective conduits 606 and 608. The pressure in conduit 606 is about 400 pounds per square inch and the fluid supplied to conduit 608 is about 1,000 pounds per square inch.
Conduit 606 is connected to deliver lubricating oil through a metering orifice to the aforementioned scrap cutter 68 by way of conduit 610 and is also connected to the aforementioned conduit 508 leading to the feed roll illustrated in FIG. 23.
Conduit 610 also leads to the inlet side of a pressure reducing valve 612, the output side of which is connected to the inlet of a two position solenoid operated valve 614 having a service port connected to the flywheel brake 114, previously referred to. The outlet side of reducing valve 612 is also connected by conduit 616 with the lower ends of cylinders 284 pertaining to the bed member adjusting device. Conduit 616 is also connected to relief valve 613 to permit escape of fluid from the lower side of cylinders 284 as the press bed 46 is adjusted downward.
The higher pressure conduit 608 is connected by way of conduit 618 with the inlet port of another two position solenoid valve 620 having a service port connected with the upper ends of cylinders 284 and also connected to conduit 320 pertaining to clamp pistons 318.
Each of the valves 614 and 620 is a simple reversing valve and in one position connects the inlet of the valve to the service port and in another position connects the service port to exhaust.
High pressure conduit 608 is connected by conduit 622 with the inlet of still another two position reversing valve 624 having an outlet connected by conduit 123 with the caliper brakes 118 associated with brake disc 116. Similarly, conduit 608 is connected by conduit 628 with the inlet of still another two position solenoid operated reversing valve 630, a service port of which is connected by conduit 124 with the other caliper brakes 120 pertaining to brake disc 116.
High pressure conduit 608 is also connected by conduit 126 with the caliper brakes 122 associated with braking disc 116 and, as previously mentioned, is also connected to conduit 518 leading to the feed roll control circuit of FIG. 20.
The aforementioned low pressure conduit 606 is connected with a manifold 636 from which a plurality of lines lead to the crankshafts and cylinders and gears for supplying lubricant thereto. The lines leading to the crankshafts are indicated at 638 and have swivel fittings 640 while the lines leading to the cylinders are indicated at 642 and the line leading to the drive gears is indicated at 644.
Modifications may be made within the purview of the appended claims.