Patent GB-880419-A (GB)
Title: Cutting-press
IPC: A43D8/04
Filed: 1958-05-23
Abstract: 880,419. Cutting-out presses. MASCHINENFABRIK MOENUS A.G. May 23, 1958 [May 25, 1957], No. 16712/58. Class 31 (1). An electrically-controlled cutting-out press having stationary and vertically movable press members and means for adjusting the length of the cutting stroke to the thickness of the material to be cut is characterized in that the stroke-adjusting device is positioned on one member of the press within easy acess by the operator and acts on a displaceable and normally-closed electric switch, which it displaces in relation to a cut-out member mounted in the same member but controlled from the other member of the press so as to open the switch at the end of each pre-adjusted stroke of the movable press member. In the press shown, oil is supplied from a motor-driven pump 6, Fig. 2, when a magnetic valve 8 is open, to a pressure chamber 16 at the foot of the machine post and is forced up through the bore of a spindle 20 at the upper end of which it enters, through holes 22, a chamber 24 in a piston 26 fixed on the spindle 20. The piston is associated with a cylinder 30 supported on a column 31, and spaced from the piston is a collar 32 attached to the spindle 20 and having a groove 34 to receive one end of a bell-crank lever 40 pivoted at 38 on the swing arm 36, the other end of the lever 40 carrying a plate 42. Positioned on the swing arm 36 is a graduated rotatable knob 44 attached to a shaft 46 carrying a bevel gear 48 which meshes with a bevel gear 50 on a screw-threaded shaft 52 rotatably mounted on a bracket 54 in the swing arm 36. When the knob 44 is turned, the shaft 52 is also turned, thereby moving forwards or backwards a slide 56 on which is adjustable a bearing plate supporting a contact block 64 which consists of a normally-closed switch 66 and a spring- pressed pin 68. The swing arm 36 is moved over a platen 37 by means of a handle 70 provided with normally-open contacts 72, 74 which can be closed by the actuation of a push-button 76. In operation, the knob 44 is turned to adjust the contact block 64. The swing arm is then moved over the platen and the machine tripped by means of the push-button 76. This causes an electric circuit to be closed through the valve 8 and allows oil to pass into the chamber 24 and thereby causes the cylinder 30, column 31 and swing arm 36 to be depressed to push the die through the material on a cutting block 39 positioned on the platen. The depression of the swing arm causes the bellcrank lever 40 to move counterclockwise about its pivot 38 and the cutting stroke as set by the knob 44 is ended as soon as the plate 42 on the bell-crank lever has pushed the pin 68 sufficiently far into the contact block 64 to open the switch 66. The position of the valve 8 is thereby reversed so that the oil no longer flows into the cylinder 30 but is allowed to escape into the oil sump. A spring 80 returns the parts 30, 31 and 36 to their initial position. A second switch with a contact pin is mounted alongside the first switch to act as a safety device. The machine may be provided with a two-handle control to protect the hands of the operator. The invention, which is not limited to swing arm presses, may also be applied to electrically-controlled mechanically - driven cutting - out presses. Further, the hydraulic means may be replaced by any other pressure-applying means.