Title:
Automatic tube cutoff
United States Patent 2325431


Abstract:
This invention relates to flying shear or automatic cutoff machines arranged to operate on continuously traveling stock to cut- the same to given length during forward travel. An object of the invention is to provide an im- 6 proved machine especially adapted for operation on flat sided hollow...



Inventors:
Shippy, Leo C.
Application Number:
US44343542A
Publication Date:
07/27/1943
Filing Date:
05/18/1942
Assignee:
GEN MOTORS CORP
Primary Class:
Other Classes:
83/319, 83/320, 83/363, 83/370
International Classes:
B23D25/04
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Description:

This invention relates to flying shear or automatic cutoff machines arranged to operate on continuously traveling stock to cut- the same to given length during forward travel.

An object of the invention is to provide an im- 6 proved machine especially adapted for operation on flat sided hollow tubing by incorporating a reciprocatory knife designed to first pierce the tubing and then cut through the walls in an outward direction so as to avoid inward collapse I1 and tube deformation together with a pair of retractible tube supporting clamps or split dies to buck the wall during the severing operation and thereafter to open apart out of interference to the progress of severed tube ends through the 1 die.

A further object of the Invention is to provide a reciprocable knife carriage actuated in the forward direction by fluid pressure under control of a valve which is triggered by the advance of the 2 tubing to a predetermined point and is reset by carriage travel to its forward limit. By cycling carriage actuation in relation to the rate of tube travel the length to which the tubing is cut can be varied and such control is conveniently a-f i forded by mounting the valve triggering mechanism for adjustment to selective spaced relation with the point of knife operation. Operation of the knife is also by fluid pressure under control of a valve actuated at a given intermediate point in the forward travel of the carriage.

Simultaneously with knife projection the retractible tube clamps are brought into action and with the retraction of the knife after the severing operation the tube clamps are allowed. to open prior to return travel of the carriage.: With the retraction of the split clamps the revered tube ends, especially if they are burred, do not jam in the die but the length of tube-cutoff drops from the machine and the end of the. oncoming tube travels forward as the carriage moves back until the advancing tube end strikes the trigger and again cycles the cutoff operation.The structure of the machine and its operation will be better understood upon reference to the accompanying drawings wherein Figures 1 and 2 are a side elevation and a top plan view, respectively, of the cutoff machine: Figure 3 is an enlarged transverse sectional view taken on line 31-a. of Figure 1; Figure 4 is a longitudinal sectioral view taken on lines 4-4 of Figures 2 and 3; Figure 5 is a horizontal section on a still larger scale and is taken on line 5-5 -of -Figure 3; Figure 6 is a transverse section on line 6-4$ of Figure 5 and shows the split die in retracted position; Figure 7 is afragmentary section showiiug the split die in-contracted position at the start of the severing operation; Figure 8 is a detail section on line 8-8 of Figure 3; Figure 9 is i a fragmentary plan' View showing the trigger mechanism of Figure 2 but on a much larger scale; Figure 10 is a view looking in the direction of the arrows on line 10-10 of Figure 9 and Figure 11 is a transverse vertical section taken on 0 line 11i-11 of Figure 2.

As will be understood, the endless formation of the flat sided tubing Is carried on from ribbon stock supplied in rolls. - The flat stock unwound from the spool is fed through shaping apparatus, is sealed and straightened and then cut to predetermined lengths.

As the tube stock, indicated in the drawings at I, comes from the straightening machine it passes through an apertured die head of the 0 reciprocating knife carriage of the cutoff machine. This head may consist of a centrally apertured cross bar 2 which, as best seen in Figures 4 and 5, has secured thereto a die block 3 having a removable closure plate 4 and supporting a t5 stationary die 5 and slidably mounted split die clamps 6-6. In the space between the dies 5 and 6-6 is a reciprocable tube cutoff knife blade 7. The upper edge of the knife blade is recessed to substantially W-shape, as best seen in Figures 0 6 and 7, to provide a central piercing point to initiate the cut into the tube and from which piercing point diverge a pair of shearing edges which during the upward projection of the knife cut through the wall of the tube in an outward 35 direction. The shearing force being exerted in an outward direction eliminates collapse of the tube walls, the tube walls being bucked by the dies on both sides of the knife.

The split die is located on the exit side of the 49 shearing head and opens to avoid interference to passage of the tube after the shearing operation.

Thus the laterally separable clamp dies 6-each has pivoted thereto a stud 8 projecting outwardly through the wall of the die block 3 and 40 carrying a nut to seat an expansion spring 9.

The outer faces of the clamps are formed with cam or wedge surfaces for slidable engagement with corresponding wedge surfaces at the upper ends of the spaced arms of a-U-shaped slider 10. 5, This slider 10 is urged upwardly by a pair of coiled compression springs 1 which bear against lateral ears 12 on the slide and surround vertical guide pins 13 which project through the ears 12, , I . 50 In the retracted position of the parts the cross bar of the U-shaped slider 10, as best seen in Figures 3 and 4, extends under a ledge 14 formed on the connecting rod 15 to which the lower edge of the knife blade is secured. The opposite end of the connecting rod 15 is jointed to an air actuated piston IS contained within an air cylinder 17. Outward movement of the piston projects the knife blade through throh e stock and also by reason of the upwardmovement of the ledge 14 releases the slider 10 which under the action 1 of the compression springs II slides the camming surfaces on one another and contracts the split die 6-6 against the flat walls of the tube.

On the return of the knife the ledge 14 picks up the slider and allows the spring loaded split 1 clamps 6-6 to be retracted. Return of the parts is effected upon release of air pressure on the piston 16 and under influence of a pair of tensioned coil springs 18, which at their upper ends engage outwardly extending arms on the con- 2 necting rod structure and at their lower ends are anchored to pins ande hd are housed within dependent tubes 19 on the cross bar 20 of the slidable carriage.. This cross bar 20 which preferably is formed integral with the piston cylinder 17 is sus- 2 pended by a pair of posts 21 from the cross bar 22. Upwardlyprojecting pretn osts 23 on the cross bar 22 are joined to the opposite ends of the die supporting cross bar 2.

The main supporting cross bar 22 of thknife e carriage is formed with bearing heads slidable on a air of ways or obars 24 mounted at opposite ends in standards or supporting brackets 25 projecting upwardly from the bed plate 26 of the machine. Also mounted on the slide bars 24 near the tube entrance end of the machine are the outwardly extending arms 27 for the air cylinder 28. Slidable within the cylinder 28 is a piston 29 whose forward movement is transmitted to the knife carriage by connecting linkage 30. Retraction of the carriage is accomplished through a pair of tensionable coiled springs 31 connected at their forward ends to the carriage and rearwardly enclosed by and joined to the tubes 32 which are carried by the cylinder supporting arms 27.

Closing the head of the cylinder 28 is a valve body 43 which, as best seen in Figures 4 and 11, contains a. slidable valve 44. At one end the valve 44 seats over a port 45 leading from a source of air under pressure. At its opposite end it seats over a port 46 which vents to atmosphere. The intermediate chamber of the valve body 43 communicates with the piston cylinder through either of two ports 41 and 48. The port 48 contains a* one-way check valve 49 while the port 47 is arranged to receive a projecting stud 50 on the head of the piston 29. In operation when the valve 44 is moved to the left in Figure 11 the vent to atmosphere is closed and air under pressure lifts the check valve 49 and acts against the head of the piston 29 to move the knife carriage forward. When the valve 44 thereafter is returned to the position shown in Figure 11 the air under pressure is cut off and the piston cylinder is vented through the ports 46 and 47, allowing piston return as the springs 31 restore the knife carriage. The-rapid return and abrupt stop of the carriage is eliminated by the fit of the projection 50 into the port 47 in the final range of piston return movement. This fit is such as. to allow trapped .air-to act as a cushion and 1 thereafter bleed out to atmosphere. t The operating stem for the valve 44 projects I through the valve-body 43 and is engaged by one 75-1 end of a pivoted lever 51 which is held in engagement with the valve stem by a coil spring 52. The opposite end of the lever is connected by a link 53 to a crank arm 54 fixed on the end of a rockshaft 55. This rockshaft has its end, adjacent the crank 54, supported in a bearing or upright post 56 and extends longitudinally of the machine where its opposite end is secured or welded to a splined sleeve 5t on which is slid0 ably keyed a collar 58 rotatably mounted in a supporting bearing 50. The bearing 59 is connected to a longitudinally adjustable block 60 slidably dovetailed on a fixed support 61 and threadedly receiving a screw shaft 62 which pro5. jects beyond the end of the the machine and carries a hand crank 63. Supported above the block 60 by an upright 64 is a plate 65, which among other thing s carries a pointer finger 6 movable over a scale 57 on which markings may be placed to 0 indicate the distanc fo e from the knife cutoff operation to which the supporting block 0o is set by the screw 62 and hand crank 63.

Also carried by the plate 65 is a funnel-shaped guide 68 to lead the end of the oncoming tube 5 to the restricted end of the guide where there is located the trigger release mechanism controlling the operation of the valve 4. This mechanism (see Figure s) includes a pivoted bell crank 69 having a pad urged by a coil spring 70 against 0 the end and over the throat of the guide 68.

Pivoted in the other arm of the bell.crank 69 is a pawl 71 normally pressed outwardly by a looped spring 72, for engagement at its end with a bell crank latch 73. A coil spring 74 normally holds the latch in engagement with a stop 75 in position to obstruct swinging movement of a lever 76. The lever 7. is keyed on the upper end of a vertical shaft 77 which at its lower end has projecting therefrom a lever 78 linked by a tie rod 19 to a radial arm 80 fixed on the collar 58. The slidable spline connection between the collar 58 and the shaft 55 accommodates longitudinal adjustment of the parts by the hand crank 63.

In operation when the trigger mechanism is set by: the hand crank 63 for the desired length of tube to be cut off, the end of the tube is directed by the funnel guide 63 into striking engagement.with the trigger 69 rocking the trigger to trip the latch 73 and release the lever 76. This frees the rockshaft 55 for rotation in a counterclockwise direction (as viewed in Figures 3 and 11). Such movement occurs under influence of the coil spring 81 anchored at one end to the laterally projected tail of a fixed frame bracket and intermediate rockshaft journal 82 and hooked at its other end to one arm of a bell crank 83 clamped to the shaft 55 at an intermediate point.

Operation of rockshaft 55 permits the valve 44 to open the pressure source to the cylinder 28 for projection of the knife carriage with the traveling tube. The other arm of the bell crank 83 is positioned in the path of a shoe 84 fastened on the knife carriage 22 whereby when the carriage has moved forward a predetermined amount engagement of the shoe 84 with the bell crank 83 rocks the shaft 55 in a reverse or clockwise, direction, whereby actuation of the valve control linkage at one end of the rockshaft vents the cylinder 28 and actuation of linkage at the opposite end of the rockshaft returns the lever 76 to its locked or latched position. In the reurn of the lever 76 the spring 14 yields to allow ;he latch 73 to be deflected until cleared by the ever and similarly the return of the trigger 69 mder the influence of .the spring 70 as the stock drops from the machine, is accommodated by depression of the dog 71 as it moves over and back of the latch 73.

At a predetermined intermediate point in the forward travel of the carriage the piston cylinder controlling the cutoff operation receives a shot of air under pressure through the valve body V5 constituting the head of the piston cylinder 17.

This valve body, as seen in Figure 4, has in the chamber leading to the piston, a valve 86 which seats on one side over a port 87 communicating with air under pressure and seats on its opposite side over a port 83 leading to atmosphere. Its stem projects from the valve body and is connected to an operating lever 89 biased by a spring i 90 to the vented position of the parts. A contact shoe 91 carried by the lever is arranged to engage at a predetermined point with an abutment roller 92 positioned in the path of the shoe whereby to rock the lever 83 and move the valve * 86 to close off the atmosphere port 83 and enable air under pressure to raise the piston tC. The shoe 91 moves on past the abutment 92 during the continued further movement of the carriage thereby allowing the valve a to be restored to cylinder venting position and the knife 7 to be retracted and the split clamps 6-6 to be separated.

Thereafter the return of the carriage is effected by the pull of the springs 31 upon engagement of the shoe 84 with the rock lever 83 controlling the valve 44 in the manner before described. As the carriage moves back the shoe 91 again contacts with the abutment 92 and in order to prevent operation of the knife on the return stroke of the carriage, the abutment roller 92 is mount- 3, ed on a swinging frame 94 having outwardly projecting pins which, as best seen in Figure 3, pivot the lever on a supporting bracket 95. A coil spring 96 normally holds the lever in upright position with its lower end in limiting engagement with the bracket 95 but yields to allow the lever to swing back for the return passage of the shoe 91. As seen in Figure 4 the bracket 95 is secured to a stationary part of the machine by the set screws 97 which pass through elongated openings 4ý in the bracket and thereby allow the bracket to be set in selected fore and aft positions in order properly to time knife operation.

I claim: 1. In a cutoff machine of the character de- 5 scribed, a movable knife carriage, a fluid pressure responsive device operatively connected with the carriage, a valve controlling the response of said device and being fixedly mounted on the machine, spring means biasing said valve to active s5 position, latching mechanism operative to hold the valve in inactive position and against its release to the biasing force of said spring means, a trigger engageable by the forwardly traveling stock to release the latch, a one-way ratchet trip 6 for transmitting latch releasing movement from the trigger, means actuated by the travel of the carriage near its forward limit to restore the valve to inactive position and to cause the latching mechanism to resume its valve latched rela- 6 tion regardless of the then existing trigger position, spring means to cock the trigger and its ratchet trip back into position wherein the trip is conditioned for transmitting releasing movement to the latching mechanism, an adjustable 7 support for the latching mechanism and its trigger as a unit to enable selective variation of the set distance thereof toward and from the range of carriage travel and thereby regulate the length of stock cut off and adjustable connections between the latching mechanism and the valve accommodating variations in trigger setting.

2. In a cutoff machine of the character described, a knife carriage operating device and means regulating the operation thereof including a power feed controller, a rockshaft having crank arms at opposite ends thereof, an operative connection between said controller and the crank at one end of the rockshaft, a latch operatively connected to the crank at the opposite end of the rockshaft, a latch release trigger engageable by the forward end of the traveling stock after a given length has reached beyond the knife carriage and operable thereby to trip the latch and free the rockshaft andock a rocker arm fixed to an intermediate portion of the rockshaft in the path of the traveling carriage near its forward limit and operable thereby to return t ren he rockshaft to latched position.

3. In a cutoff machine of the character described, a knife carriage operating device and means regulating the operation thereof including a power feed controller, a rockshaft operatively connected at one end to said controller, a latch operatively connected to the opposite end of the rockshaft, a latch release trigger engageable by the forward end d of the traveling stock after a given length has reached beyond the knife carriage and operable thereby to trip the latch and free the rockshaft, a lever fixed to the rockshaft in the path of the traveling carriage near its forward limit and operable thereby to return the rockshaft to latched position, means mounting the latch and trigger for adjustment toward and from the carriage operating device for selectively setting the length of stock cut off and a slidable key connection between the latch and the adjacent end of the rockshaft to accommodate said cutoff length adjustment.

4. In a cutoff machine of the character described, a movable knife carriage having a head through which is fed the continuously traveling stock, means active after a given length of stock has fed past the head to move the carriage forward with the traveling stock, a stock cutoff knife ) reciprocably mounted in the head, means to actuate the knife at a given point in the forward movement of the carriage, a pair of retractible stock supporting clamps arranged for engagement with the stock adjacent the line of knife cleavage, spring pressed cams to contract said clamps upon projection of the knife, and a follower connection between the cams and knife for relieving the cams upon retraction of the knife.

5. In a flying shear machine having a stock 0 guiding head and a reciprocatory knife slidable in the head to cut through the stock, a pair of stock embracing clamps for cooperation with the knife, spring means normally biasing the clamps open, a reciprocatory clamp closing member hav5 ing bearing engagement with the clamps to contract the same upon member projection and having lost motion connection with the knife for retraction therewith and spring means active on said member to project the same into clamp ·0 wedging relation upon projection of the knife.

LEO C. SHIPPY.