Patent GB-562607-A (GB)
Title: Improvements in means for safeguarding operators on power presses
IPC: F16P3/04
Filed: 1943-03-01
Abstract: 562,607. Machinery guards. WELLS & CO., Ltd., A., and WELLS, A. W. J. March 1, 1943, No. 3307. [Class 80 (iv)] [Also in Group XXV] Consists in a guard for presses and like machines which can be placed in an operative position when the press &c. is to be used for forming and thrown back into an inoperative position when the press is to be used for blanking operations. In the former case the guard is interconnected with the starting means so that it has to be closed before the press can be started and cannot be opened while the press is working. A non-repeat mechanism is provided which can be disconnected when the press is to be used for blanking. The guard comprises two side members 10 joined by a crossmember 11 rotatably mounted thereon, the side members being pivoted on studs 12 so that the guard may be swung from its operative position (full lines), Fig. 2, to its inoperative position (broken lines) when blanking is to be performed. To each side member is fixed a fork member 14, Fig. 2, serrated teeth on which engage similar teeth on a. bar 15 fixed to the machine frame, so that the distance of the guard from the press may be adjusted. The guard is in two sections, a lower section 19 slidable up and down in the side members and an upper section 20 fixed to the member 11 and connected to the lower section by links 24 pivoted to arms 25 on the member 11. The closed position of the guard is shown in full' and the open position in broken lines, with the section 20 swung inwardly and the lower section 19 down. The guard is. closed by the operator pulling the lower edge of the upper section. Located within a cavity 27, Fig. 3, of the press is a locking bolt 28 normally urged rearwardly by a spring 29 to engage a hole 30 in a slide 31 for releasing the clutch dog to start the press. The bolt is actuated by links 32, 34 and bell-crank 35, the arm 36 of which has a slot 37 engaging a pin on the bolt. The outer end of the link 32 is pivoted to an arm 39 fixed to the bar 11 and thus movement of the guard sections determines the operation of the slide 31. This locking mechanism is similar in principle to that described in Specification 528,343. The connection between link 32 and arm 39 is readily detachable to enable the guard to be swung upwardly to its inoperative position in which slotted extensions 43 of the side members engage studs 44, Fig. 2, and are secured. by nuts 45. The bolt 28 not being required in this position (for blanking), is secured to a prolongation 47, Fig. 2, of the extension 43 by a pin 41 passing through hole 50 in part 47 and hole 51 in a plate 48 integral with the link 32. The pin 41 is key-shaped and may be used for the connection between 32 and 39. The guard cannot be moved down without removing the pin and therefore permitting the bolt 28 to return to locking position. The release slide 31, Fig. 4, is urged by springs 52 upwardly to a position where it is'engaged by the bolt 28 and where it engages a pivoted dog 54 mounted to turn with the press shaft 55 and holds it in a position in which the shaft is not coupled to the rotating flywheel. When the slide is moved down the released dog 54 is rotated by a spring 57 to clutch the shaft to the flywheel by a key 58 as described in Specification 562,606. After the shaft has almost completed a revolution the dog is intercepted by the slide to declutch and prevent the ram from descending a second time. The shaft carries a cam 59 to actuate a brake 60 towards the end of the upstroke. On depression of the treadle, a rod 61, Fig. 4, is raised and, through lever 62 lowers a pivoted bar 64 a latch 65 on which depresses a nose 67 on the slide 31, providing the bolt 28 has been withdrawn, to free the dog and engage the clutch. On the press shaft is mounted a cam 68 co-operating with a roller 69 on the release slide, the cam being so shaped that, notwithstanding release of pressure of the operator's foot on the treadle, the springs 52 cannot lift the slide until some time during the last quarter of the upstroke of the ram and, therefore, opening of the guard, until this time, is prevented. To prevent a repeat stroke in case the operator should maintain the pedal depressed, a roller 80 mounted on a shank 71, Fig. 6, screwed into a split cone 72 locked by a key 73 in a recess in a member 70 fixed to the shaft, strikes the bar 64 during the up-stroke of the ram and releases the slide 31 which will be drawn up by the springs 52 and locked by the bolt 28. When the roller has passed the bar 64 the latter springs back with the latch below the nose 67 on the slide, so that upon release of the pedal, the latch will wipe over the nose and engage above it for normal actuation. When the press is to be used for blanking, the non-repeat roller is removed and, to prevent it from being lost, is screwed into a recess 74. A further safety device comprises a pin 77, Fig. 3, connected by a link 75 to an arm 76 of the bell-crank 35 and adapted to enter a hole 78 in the shaft 55 when the guard is opened. The press includes a shear pin and stop mechanism as described in Specification 562,606. The Provisional Specification refers to Specification 302,061, [Class 80 (iv)].