GB588368A - Improvement in counting mechanisms - Google Patents

Abstract

588,368. Clutches. TRIGGS, W. W. (Gilbert & Barker Manufacturing Co.). Aug. 8, 1944, No. 15064. [Class 80 (ii)] [Also in Group XIX] Friction clutches. A clutch used in the driving connections to a counting mechanism (see Group XIX) comprises a drum 34, Fig. 3, free on the driven shaft 35 and having bevel teeth 33 meshing with a bevel pinion 32 on the driving shaft 25. The hub 40, Figs. 7, 8, of a disc 36 is fixed to the driven shaft 35, and is formed with a pair of slots in which slide horizontally fingers 43 projecting axially from a collar 37 slidable on the shaft 35. Toggle links 50 are pivoted in the fingers 43 so that when the latter are moved to the right, Fig. 7, the links rock anti-' clockwise levers 48, Fig. 8, pivoted on studs 49 in the disc 36. The levers 48 cause bands 45 to be expanded against the inner surface of the drum 34 to connect this drum to the disc 36 and shaft 35. The collar 37 is moved to the left by an operating bar 38 to break the toggle and open the clutch. Flat springs 51 bear on the bands 45 and levers 48. The arrangement is such that when the toggle is broken and the clutch disengaged, the bands 45 bear with a slight pressure against the drum 34 to prevent uncontrolled movement of the driven shaft. Ratchet clutches. Two types of ratchet clutch are described. (1) The drive to the units drum 70, Figs. 9, 10, of the counter referred to above is applied to a gear 68 fixed to a hub 79 freely carrying the drum. The hub 79 is keyed to the counter-supporting shaft 69. Dogs 82 are pivoted in the hub and pressed by springs 84 so that, during the normal anticlockwise movement of the counter-supporting shaft, the dogs engage the inner wall 83 of a recess 76 in the units drum and so drive this drum. When the countersupporting shaft is turned clockwise to zeroize the numeral drums, the dogs 32 drag the units drum round until it is arrested by a zero stop. 12) After the friction clutch described above has been disengaged by its operating mechanism (see below) a pinion 127, Fig. 5, free on a shaft 35 is turned anticlockwise so that the end 143 of a pawl 142 pivoted to the pinion clears a pin 144 on a lever 145, the pawl then moving by gravity to engage a ratchet wheel 141 fixed to the shaft 35 to couple this shaft to the pinion. Towards the end of a revolution the pawl 142 rocks the lever 145 clockwise, the end of the pawl escaping past the lever. The pinion 127 is later returned a short distance anticlockwise, the pin 144 then disengaging the pawl 142 from the ratchet 141, anticlockwise movement of the lever 145 being prevented by a stop 146. Positive clutches. The drive for the tens drum 71 is derived from a pinion 97, Figs. 9-12, having internal teeth 113 normally engaged by a pawl 115 on a pivot 116 fixed to the web of the tens drum 71 so that this drum is advanced in the anticlockwise counting direction. This connection is disengaged by the clockwise movement of the counter-carrying shaft 69, this movement, by clutch dogs 101, turning a flanged disc 103 against which is held by a spring 110 a friction disc 109 having a cam slot 119 engaging a pin 120 on the pawl 115 to rock this pawl anticlockwise. Operating clutches. A hand-operated shaft 39, Figs. 3, 4, carries a disc 134 having a notch 135 engaging a roller 137 on a segment 136 coupled to a cam disc 132 which shifts a bar 38 to disengage the friction clutch described above. The shaft 39 also drives the pinion 127, Fig. 5, which operates the ratchet clutch described above. Specification 564,736 is referred to.