GB324937A - Safety device for automatic screw machines - Google Patents

Abstract

324,937. Fairweather, H. G. C., (National Acme Co.). Aug. 7, 1928. Interconnecting guard or protector with starting-gear. - In '' Gridley " multiplespindle and other automatic screw machines having a shaft adapted to be driven alternatively by a power clutch or by hand, means interconnected with the clutchshifting gear are provided to prevent attachment of a band-crank to the shaft while the clutch is engaged, and to prevent clutch engagement while the crank is in place, in order to avoid injury to the operator. In a " Gridley " machine, the transverse shaft 2 is driven at high speed through a clutch 3 and receives at its end 9 a detachable hand-crank 10 for turning the machine during tooling, repairs, &c. The safety device, which is applicable to existing machines, comprises a rock-shaft 16, borne by brackets 12, 13 and carrying a manipulating- lever 17 with a recess 18 to fit over the shaft end 9, and an arm 19 provided with a pin 20 engaging a notched block 28 slidable in a swinging arm 24. The arm 24, which carries an extension 25 connected to the hand control-bar 8 for the clutch 3, is secured to a shaft 26, which is oscillated by the automatic clutch-control cam 6 acting on an arm 5, and carries loosely the clutchfork 4. The shaft 7 of the cam 6 is geared to the shaft 2, but receives also a slow-speed drive from a different source. When the lever 17 is thrown over to mask the shaft end, as shown in Fig. 5, the block 28 projects a pin 27 into a hole in the fork 4, which is thus coupled up to shift the power clutch into engagement, manually or automatically, the pin 20 engaging an orifice 23 in the arm 24, so locking the lever 17. If, when the lever 17 is withdrawn and the handle 10 is in place, the arm 24 is idly rocked forward, the pin 20 engages a second orifice 22 to lock the lever 17. A spring detent 29 coacts with sloped faces on a fixed part 30 to bias the lever 17 to its extreme positions.