Patent GB-697292-A (GB)
Title: Adjustable stopping device for stopping the movements of a sliding member in a machine tool
IPC: B23Q5/52
Filed: 1950-07-18
Abstract: 697,292. Lathe details. DANSK INDUSTRI SYNDIKAT COMPAGNIE MADSEN AKTIESELSKAB. July 18, 1950 [July 28, 1949], No. 17934/50. Class 83 (iii). An adjustable stopping-device, to limit the motion of a slide in a machinetool in which the slide is moved by turning a shaft 1, Fig. 1, until this is stopped in a predetermined position by engagement between a stop and a member moved with the shaft, and an adjustment mechanism serves to change the predetermined position, comprises a pawl 4, Fig. 3, controlled by a mechanism to stop a pawl-wheel 3 connected to the spindle 1 when the slide is in one of the predetermined positions. As applied to limiting the depth of feed of the tool-slide in a lathe, the device is an attachment mounted on the feed-shaft 1. The wheel 3 is fixed to a sleeve 2, Fig. 1, and has face-teeth geared to a member 7 keyed to the spindle 1, the sleeve being rotatable on the spindle and having an adjusting hand wheel 8 and a scale drum 9 for co-operation with a pointer on the casing of the device. To uncouple the sleeve 2 from the shaft 1, for setting the device, the member 7 is moved by depressing a spring-urged handle 38, Fig. 3, which engages and rocks with its lower sloping end 39 a lever 40 pinned to the member 7 and pivoted in the casing of the device, the handle 38 remaining in the depressed position by engagement between a recess in the end 39 and the co-operating pin in the lever 40. A projection on the base of the lever 40 engages a spring-pressed shaft 41, Fig. 1, connected by a ring 45 to a spindle 24 so that, upon the lever being rocked, gears on the ends of the spindle are carried out of engagement with a single tooth 25 on the front face of the ratchet 3 and a gear 12 secured to a hollow spindle 10 rotatable on the sleeve 2. With the gears on the spindle 24 in engagement, rotation of the hand wheel 8 rotates the spindle 10 intermittently as the tooth 25 encounters the geared end of the spindle 24 once during each turn of the hand wheel. The spindle 10 and the sleeve 2 have sets of discs 13 driven frictionally thereby, each disc 13 being formed with a notch 14, Fig. 2. Feelers 15, 16, arranged over the discs 13 in each set, are rotatable on a holder 17 which can be moved along its supporting shaft 18 against spring pressure by turning a knob 26 to locate the feelers over any pair of discs. The knob is secured to a cam-plate 28 caused to move the holder 17 through engagement with pin 30 thereon. The feelers 15, 16 are urged towards the discs 13, against the action of springs 19 rigidly fixed on the feelers, by a release 22 which is mounted on a spindle 6 that also carries the pawl 4, the springs 19 being deflected by a pin 20. The pawl 4 is connected to the holder 17 and, with the holder, is spring-urged to rotate anti-clockwise so that a plate 23 carried by the release 22 engages stop-pins 21 projecting from the feelers. When the ends of the feelers enter the slots 14 in the discs 13 simultaneously, the pins 21 rotate out of engagement with the plate 23 to allow rotation of the release 22 and the pawl 4 which engages the ratchet 3 to prevent further feeding of the tool-slide, the feelers being returned immediately to the raised position by the springs 19. To adjust the device for a different pre-set depth of feed, the knob 26 is rotated to re-position the feelers and withdraw the pawl 4 by engagement between the prongs of a star-cam 31 on the knob and the release. This engagement returns the plate past the pins 21 into the position shown in Fig. 2. The stoppositions are set by depressing the handle 38 to uncouple the sleeve 2, shaft 1 and the spindle 24, and depressing a spring-pressed plunger 32 provided with pins 20, 34 to engage the springs 19. A cam-surface 35 in a shaft 33 for the plunger 32 engages a plate 36 on the release 22 to cause rotation thereof into an inoperative position in which it is retained by co-operation between a notch 37 in the shaft 33 and the plate 36, the feelers being forced against the discs 13 by deflection of the springs 19 caused by the pin 34. The hand wheel 8 and the scale-ring 11 fixed to the sleeve 10 are turned separately until the feelers 15, 16 engage the notches 14 in the pair of discs 13 in the operative position, further rotation to the desired stop position indicated by the scales causing slipping of the discs on their supporting shafts. The other pairs of discs may be set in a similar manner after re-positioning the feelers and again depressing the plunger to carry the release to its inoperative position. The scales on the hand wheel 8 and the ring 9 are then set by turning a test specimen, uncoupling the shaft 1, sleeve 2 and the spindle 24 by the handle 38, disengaging the release 22 by depressing the plunger 32, and adjusting the scales to agree with the gauged diameter of the machined specimen. The stoppositions are limited to whole multiples of the feed corresponding to the pitch of the teeth on the ratchet, and the whole device may be adjusted, about the axis of the shaft 1, on the apron of the slide by an amount corresponding to the above pitch by a micrometer screw 47, Fig. 3, having a graduated head 46 and serving to clamp a projection 48 of the apron against a spring-pressed plunger 49 in the device.