Patent GB-668826-A (GB)
Title: Improvements in guillotine machines for cutting paper and other materials
Inventor: FAWDRY CHARLES FREDERICK
IPC: B26D7/22
Filed: 1948-04-30
Abstract: 668,826. Machinery guards. SOAG MACHINE TOOLS Ltd. April 25, 1949 [April 30, 1948], No. 11958/48. Class 80 (iv). A guard 1 of a guillotine machine adapted to move forward from an inoperative position shown in Fig. 3 to push the operator away on the working stroke of the machine is first set in motion on initiation of an operation of the machine and after the completion of a predetermined movement sets the actuating mechanism of the knife and work clamp in operation. A machine operation is started by raising a starting handle 15, Fig. 4, which lifts an arm 39 to swing a bell-crank lever 37, 35 to engage a pawl 19 with a continuously driven ratchet wheel 16. The pawl 19 is mounted on a freely pivoted arm 18, 21 which is thereby moved to actuate the guard through a connecting rod 13 (see both Figs. 3 and 4) to its operative and safe position whilst the pawl 19 is maintained in engagement by an arcuate guide 32. The arm 18, 21 also operates simultaneously a rod 25, lever 27, a helical gear segment 30 and a helically toothed rack 31 to slide a control rod 32 for the knife and clamp actuating mechanism in the direction of the arrow shown in Fig. 8. Referring to the latter Figure, the rod 32 carries an adjustable stop 46 which after a predetermined movement of the guard has been made engages an arm 48 of a bell-crank lever to operate, through a rod 52, a bell-crank 54, 56 which raises by a projection 57 thereon a trip lever 58 secured to a lever 60 and normally held by a roller 77 on an arm 78. The lever 60 is secured to a shaft 55 which is then rotated in the direction indicated by the arrow by a spring (not shown) to release a brake and let in the machine clutch for actuating the knife and work clamp for a working stroke through a slipping clutch as described in Specification 640,077, [Group VIII]. The movement of rod 32 also moves a block 47 thereon and a link 62 pivoted thereto to the position shown dotted in Fig. 8, this link 62 together with another link 65 coupled to a lever 67 acting as a toggle against a spring 69. The operation of the knife and clamp actuating mechanism effects rotation of a cam shaft 73 and rocks a shaft 68 carrying the lever 67. The lever 67 first rotates clockwise and operates the toggle 65, 62 over the dead centre position until the links 65, 62 are in line and then returns to its original position and in so doing returns the rod 32 also to its original position as shown, which operation also operates the guard mechanism in the reverse direction to bring it back to its inoperative position. Meanwhle a cam 74 on the shaft 73 which is rotated by the knife mechanism acts on a roller 80 of a stopping lever 79, 78 which is thereby rotated in an anti-clockwise direction. The roller 77 thereon engages with the trip lever 58, which has been returned to its original position by a spring 49 on return of the rod 32, and moves it in the direction of the arrow to operate the lever 60 and shaft 55 in a direction to disengage the machine clutch and apply the brake to hold the knife in the raised position after the completion of a working operation. A second cam 75 of the shaft 73 may operate safety mechanism in the event of over-running of the machine as described in Specification 644,943.