Patent GB-1086246-A (GB)
Title: A shearing machine and method of shearing
Inventor: HAUSMAN ALBERT FRED
IPC: B21D28/00
Filed: 1965-03-12
Abstract: 1,086,246. Dividing. AMSTED INDUSTRIES Inc. March 12, 1965, No. 10695/65. Heading B3W. A punching or shearing machine comprises a fixed cutter, a movable cutter and a reciprocable ram which can be held in a retracted position remote from the movable cutter and when released is impelled forward by a body of compressed gas to strike the movable cutter and accelerate it to a velocity of at least six feet per second at the start of the shearing operation. The punching machine.-A ram 15 is guided for vertical reciprocation in a frame 11, 13 by rollers 16. A piston 19 is attached to the ram by a rod 17 and runs in an open-ended cylinder 18, the upper part of which is enlarged to form an accumulator. The displacement of the piston is small compared with the volume of the accumulator, which is supplied with compressed air through a valve 22. The ram is raised against the air pressure by a spiral cam 27 mounted on a main-shaft 25. The ram is released when the cam-follower 28 drops off the edge of the cam. The descent of the ram is limited by stops 29, Fig. 2 (not shown). In the embodiment described two punches 35 co-operate with dies 33 to pierce holes in a component P. The components are located by spring-pressed guides 64, Fig. 3, and are clamped by a hold-down and stripper plate 34 acted on by springs 152. The plate 34 is lifted to allow feeding of the components by a cam 154. The punches 35 are lifted after the piercing operation by forked levers 42 operated, through a lever 44, by a cam 46. The feeding mechanism comprises a magazine 60 in which the blanks are stacked and a feed slide 62 to which is secured a feed tongue. The feed slide is reciprocated by a lever 75 mounted on a shaft which is oscillated by a cam 70 through a pivotally-mounted arm 71, a link 72 and an arm 73. Each forward movement of the feed slide pushes a fresh component under the punches 35 and ejects the previous component. The ram can be retained in the elevated position by two independent latches. The first latch comprises a plunger 51, operable by a lever 52 to project into the path of the ram. The second latch comprises a plunger 56 movable by a lever 57 into the path of the ram and connected to the feeding mechanism, so that when this latch is operated the feed slide is held in the retracted position. A punch engaging member 40 is screwed into the bottom of the ram and is vertically adjustable to vary the movement of the punches. The shearing machine shown in Figs. 7 and 8 is adapted to cut pins from wire stock 90, which is fed by a reciprocating clamp 92. A stationary clamp 91 prevents retrograde movement of the stock. The clamp 92 is driven from a main shaft 95. The stock passes through a fixed apertured cutter 96 and a movable apertured cutter 97. The movable cutter slides between wear shoes 101 and is acted on by a spring loaded shoe 102 to maintain the cutters in abutting relationship. A further spring 104 biases the cutter 97 to a position, determined by a flange 105, in which the apertures are aligned. The movable cutter is moved through its shearing stroke by the impact of a ram 113. The rear end of the ram forms a cylinder which runs on a fixed piston 117. A bore through the piston communicates with a passage 119 leading to an accumulator 120. The ram is retracted by a yoke 121 connected to an eccentric 127, on the shaft 95, by a rod 128. The yoke 121 comprises a front member 122 connected by shouldered bolts 124 to a rear member 123. The ram 113 is loosely received in the front member 122 whose rearward movement relative to the ram is limited by its engagement with a flange 126, thus providing a lost motion connection between the ram and the front member. To retain the ram in the retracted position a latch 131 is provided, which is pivotally mounted on a frame part 112 and biased by a spring 132 to engage the flange 126. In operation the ram is retracted by the eccentric 127 and at the end of its rearward movement the latch 131 engages. The eccentric then drives the yoke 121 forwards and as it nears the end of its forward movement a pin 134 mounted in the rear member 123 engages the latch and pivots it to free the ram which is driven forward by the pressure of air in the cylinder and the accumulator. Forward movement of the ram is limited by a resilient pad 136, while a similar pad 137 limits forward movement of the cutter 97.