United States Patent 3816874
A hock and neck cutter having a pair of arcuate cutting blades pivotally mounted on the housing, a pneumatic piston and cylinder assembly mounted on said housing and a compound linkage assembly connecting said piston and cylinder assembly to said cutting blades to provide decreasing speed and increasing force in the movement of said blades. A low-force air valve is used to control the pressurization of the piston and cylinder assembly and a discharge air silencer is provided in the discharge passage of the piston and cylinder assembly.
Application Number:
05/347180
Publication Date:
06/18/1974
International Classes:
A22B3/08; A22B5/00; A22C17/06; B23D29/00; A22B3/00; A22C17/00; A22C21/00
Field of Search:
17/11,12,52
Primary Examiner:
Mancene, Louis G.
Assistant Examiner:
Weinhold D. L.
Attorney, Agent or Firm:
Barry, Ronald E.
Claims:
I claim
1. A hock and neck cutter comprising,
2. The cutter according to claim 1 wherein said connecting means includes a pair of lever arms each having one end connected to a common point on said cylinder assembly and the other end to a point on the blades spaced from the pivot point of the blades.
3. The cutter according to claim 1 wherein said pressurizing means includes a trigger controlled low force air valve assembly mounted in said housing to control the admission of air to said inlet passage.
4. The cutter according to claim 1 wherein said pressure responsive valve member includes a valve element and a valve stem, a V-shaped seal ring mounted on the outer periphery of said valve stem in a position to seal the air inlet passage, said V-shaped seal ring collapsing in response to the force of air entering the passage to allow air under pressure to pass into said cylinder assembly and responding to discharge air to open the discharge passage.
5. The cutter according to claim 1 including means for silencing the discharge air as it is discharged from the cylinder assembly.
6. A hock and neck cutter comprising:
7. The cutter according to claim 6 wherein said cutter blades are identical and each blade includes a radiused cutting edge.
8. The cutter according to claim 6 wherein said valve includes a V-shaped seal ring positioned to bypass inlet air past the valve into said cylinder assembly and to direct the discharged air to atmosphere.
Description:
SUMMARY OF THE INVENTION
The hock and neck cutter of this invention is a fast acting device that can be controlled by a small amount of manual force. A unique compound linkage arrangement provides a decreasing rate in the speed of closing movement and an increasing cutting force as the cutter blades close. By providing a decreasing rate of speed in closing, there is no necessity for having a limit stop to halt the closing momentum of the blades. A pressure responsive control valve is used to control the admission and discharge of air to and from the cylinder assembly. The cutting cycle can be stopped at any point by simply releasing the trigger actuated valve. A special exhaust silencer is provided in the exhaust line to eliminate air noise on discharge of air from the cylinder. Interchangeability of blades is achieved by using identically shaped cutter blades.
DRAWINGS
FIG. 1 is a top view of the hock and neck cutter;
FIG. 2 is a view similar to FIG. 1 with the portion of the housing and cylinder removed to show the inside of the cutter;
FIG. 3 is a side view in elevation of the cutter with a portion of the air valve and cylinder removed; and
FIG. 4 is an enlarged view of the air valve.
DESCRIPTION OF THE INVENTION
The hock and neck cutter 10 of the present invention generally includes a housing or body 12 having a pair of identical cutting blades 14 pivotally mounted on the body and actuated by means of a pneumatic piston and cylinder assembly 16. The piston assembly 16 is actuated to close the blades 14 by means of a trigger actuated valve assembly 18. A handle 20 is mounted on the body 12 in a position to provide for actuation of the valve assembly 18 by gripping the handle. Actuation of the trigger assembly 18 pressurizes the piston and cylinder assembly 16 to close the blades, and on release of the trigger assembly 18 the piston and cylinder assembly automatically retracts to open the blades.
A unique pressure responsive air valve 22 is used to direct the flow of air into the piston and cylinder assembly 16 and to direct the discharge of air from the piston and cylinder assembly 16. The noise of the discharged air is silenced by means of an air silencer 24 provided in the discharge passage 26 from the piston and cylinder assembly 16.
More particularly and referring to FIG. 3, the body 12 is shown in the form of a casting having an end plate 28 and upper and lower support arms 30 and 32. The end plate 28 includes a central aperture 34 and a number of mounting holes 36. Coaxial bores 38 are provided in the ends of each of the upper and lower arms 30 and 32. The lower arm 32 is provided with a bore 40 which is connected to a discharge air passage 42. A boss 44 is provided on the bottom of arm 32 for the handle 20.
CUTTING BLADES
The cutting blades 14 are identical so that they can be interchangeably mounted on the housing 12. Each of the cutting blades 14 includes a radiused cutting edge 46 and a hole 48. A second hole 50 is provided at the inner end of each of the cutting blades 14 at a spaced distance from hole 48. The blades 14 are mounted in the space between the ends of the upper and lower arms 30 and 32 with the holes 48 axially aligned with the bores 38. The blades are mounted for pivotal movement on the body by means of a bolt 52 which extends through the holes 38 and 48 and is retained therein by lock nuts 54. Tension is maintained in the blades by means of brass shoes 56 provided between the blades 14 and the ends of the arms 30 and 32. Although the blades are shown as having radiused or arcuate cutting edges, it should be understood that the edges could also be straight.
PISTON AND CYLINDER ASSEMBLY
The piston and cylinder assembly 16 includes a cylindrical housing 58 having one end seated on the end plate 28 of the body 12 and an end plate 60 having mounting holes 63 seated in the open end of the housing 58. The end cap 28, cylinder 58 and end cap 60 are held in a fixed relation by means of a number of through bolts 74 and nuts 76 which extend through holes 36 and 63. An air vent passage 75 is provided in end plate 28.
A piston head 62 is mounted within the cylinder 58 and is sealed therein by means of an O-ring seal 64 positioned in an annular groove 66 in the outer surface of the piston head 62. A piston rod 68 is connected to the piston head 62 and extends outwardly through the bore 34 in the end cap 28. The piston is biased by means of spring 70 towards the end cap 60. The piston head 62 is prevented from bottoming on the end cap 28 by means of a cushioning pad 29 to minimize noise. Air trapped in cylinder 58 is vented through passage 75 to atmosphere.
Air is admitted to and discharged from the cylinder housing 58 through a port 72 in end cap 60. In this regard, the end cap 60 is provided with the discharge passage 26 which intersects port 72. An air inlet port 136 is connected to the passage 26 through an orifice 138. The direction of air flow through the discharge passage 26 is controlled by means of the air valve 22 as described hereinafter.
AIR VALVE ASSEMBLY
Means are provided for controlling the admission of air under pressure to the cylinder 58 from an air pressure source 78. In this regard, the pressure source 78 is connected to the passage 40 in the lower arm 32 by means of a rubber tube 37. The passage 40 as seen in FIGS. 3 and 4 is connected to the port 136 by means of a tube 80. The flow of air through the passage 40 and into the tube 80 is controlled by means of the trigger actuated valve assembly 18.
The valve assembly 18 includes a tubular member 81 and a body member 82 having recessed grooves 84 and 86 and a central passage 88. The central passage 88 is connected to the air groove 84 by a transverse passage 90. The recess 86 is connected to the central passage 88 by a transverse passage 92. The air valve body member 82 is threadedly connected to the tubular member 81 and is sealed within the passage 40 by means of O-ring seals 94 located in annular grooves 96 on each side of the recess 84.
The flow of air through the passage 88 is controlled by means of a valve stem 96 having an O-ring seal 98 at one end to sealingly engage the inlet end of the passage 88 and an O-ring 100 at the other end to sealingly engage a shoulder 102 at the discharge end of the passage 88. The O-ring seals 98 and 100 are spaced a distance apart slightly greater than the length of the passage 88.
Under normal operating conditions, the pressure of the air in passage 40 will act against the cross sectional area of the end of valve stem 96 to force the valve stem 96 to a closed position with respect to the passage 88. In the closed position the annular recess 84 will be connected to the discharge annular recess 86 through passages 90, 88 and 92. The discharge recess 86 is vented to atmosphere through passage 42 in the lower arm 32.
The valve stem 96 is moved axially in the passage 88 by means of a trigger 104 pivotally mounted on a pivot pin 106 located at the end of the air valve body 82. The trigger 104 is positioned to engage the outwardly extending end 108 of the valve stem 96. Pivotal movement of the trigger 104 towards the valve stem will move the valve stem axially in the passage 88. The O-ring seal 98 will be moved away from the inlet end of the passage 88 allowing air under pressure to enter the passage 88. The O-ring seal 100 will sealingly engage the shoulder 102 closing the discharge end of the passage 88. Air entering the passage 88 will flow through the passage 90 into recess 84 and out through the tube 80 to pressurize the cylinder assembly. On release of the trigger 104, the air under pressure in passage 40 will act to move the valve stem 96 axially in the passage to close the inlet to passage 88. Any air under pressure in the tube 80 will be discharged through recess 84, passages 90, 88 and 92, recess 86 and out through passage 42.
LINKAGE ASSEMBLY
The piston rod 68 is operably connected to the blades 14 by means of a compound linkage assembly 110. The assembly 110 includes a member 112 having a pair of spaced flanges 114. A threaded mounting hole 116 is provided in the body 112 and a pair of pivot holes 118 are coaxially located in the flanges 114. The body 112 is threadedly mounted on the end of the piston rod 68 and secured thereto by a pin 120.
The member 112 is connected to the blades 14 by means of lever arms 122 and 124. The lever arm 122 is in the form of a single arm having a mounting hole 123 at the inner end and a pair of interconnecting flanges 126 at the outer end, each having a hole 127. The arm 122 is connected to the blade 14 by means of a bolt 128 which extends through the hole 50 at the end of the blade 14 and the holes 127 at the end of flanges 126. The arm 124 includes a pair of plates 130 each having a hole 129 at the inner end and a hole 131 at the outer end. The plates 130 are connected to the blade 14 by means of a bolt 128 which extends through hole 50 and holes 131. The inner end of the arms 122 and 124 are connected to the body member 112 by means of a pivot bolt 125 which passes through the openings in the flanges 114 of the body member 112 and the holes 123 and 129 at the inner end of arms 122 and 124.
The compound linkage assembly 110 provides for the rapid closing of the cutting blades 14 on initial movement of the piston rod 68 with a gradual reduction in the closing rate and an increase in the force acting on the blades as the piston rod approaches the end of its stroke. This can be seen in FIGS. 1 and 2 wherein the arms are shown initially at a small angular relation to each other. In the final position the arms will be positioned at a large angular relation to each other. It should be apparent that as the arms 122 and 124 spread apart, a smaller angular movement will be imparted to the blades but at a greater force.
The piston rod 68 can be lubricated by directing the discharged air from passage 42 against the piston rod. In this regard, it should be noted that the air which is used for actuating the neck and hock cutter is normally oil laden, i.e., oil is introduced into the air stream. By directing the air discharged through passage 42 against the piston rod, a small amount of oil will be deposited onto the piston rod 68.
AIR SILENCER
Air discharged from cylinder 68 is silenced by means of the air silencer assembly 24. In this regard, the silencer assembly 24 includes a body member 142 which is threadedly received in the end of the passage 26. The body member 142 includes a discharge passage 144 having a valve seat 146 at its inner end and an enlarged threaded bore 145 at its outer end. The discharge air is silenced by means of a screen 150 provided in the bore 145 at the outer end of the passage 144. The screen 150 acts to diffuse the air and thereby eliminate any noise.
DISCHARGE AIR VALVE
Means are provided for controlling the admission of air into the cylinder 58 and the discharge of air from the cylinder 58. Such means is in the form of the valve 22 provided in the passage 26 in the end plate 60. In this regard, the valve 22 includes a valve or seal element 141 and a stem 143. A V-shaped seal ring 140 is mounted on the outer periphery of the stem 143 in a position to sealingly engage the walls of passage 26. Air entering through the port 136 and orifice 138 will force the valve 22 outwardly in the passage 26 into engagement with the valve seat 146 closing the passage 144. The force of the air will collapse the seal so that air will bypass the valve stem and enter the cylinder 58 through port 72.
When the trigger 104 is released, the force of the air acting on the valve 22 will drop to zero in the passage 26. The spring 70 will immediately act on the piston head 62 to retract piston rod 68. Reverse motion of the piston head 62 will produce an increase in pressure in the passage 26 on the discharge side of the valve 22. This air under pressure will act on the V-type seal 140 to force it into engagement with the passage 26. The valve member 22 will move inwardly in the passage 26. As the valve member 22 moves away from the body 142 of the silencer 24, the passage 144 will open allowing air to discharge through the silencer 24 to atmosphere.