Patent GB-468393-A (GB)
Title: Improvements in or relating to automatic multi spindle drilling machines
IPC: B23B39/24
Filed: 1936-01-14
Abstract: 468,393. Converting rotary into reciprocating motion. RATHE, C. Jan. 14, 1936, Nos. 1175 and 10659. [Class 80 (i)] [Also in Groups XXII and XXVI] In a drilling-machine, the work-table 3, Fig. 6 (1175/36) is moved in stages past one or a number of drill-heads, and is then returned to starting position by a spring motor. The spring motor 72 connected to the shaft 29 for traversing the table 3 comprises a bracket 84, Figs. 1-3 (10659/36), slidable in guides 82, 83 of the machine frame and carrying a loose spindle 85. A clock spring 87 is secured at one end to the spindle and at the other end to a casing 86 loose on the spindle and having an eccentric exterior. A chain sprocket wheel 88 is freely rotatable on the eccentric and carries a ring of internal teeth 89 meshing with a gear 91 keyed to the spindle 85. A chain 97 runs in grooves in the guides 82, 83 and passes over sprockets 98, 99 carried by bearings 100, 101 on the machine frame. The sprocket 99 is driven by a worm 115, Fig. 7, (10659/36) and continuously rotating friction drive 117, the end thrust of the worm being resisted by a spring 118. When the table 3 is held stationary by the drum 34 engaging one of the stops 36 .. 39, Fig. 6, 1175/36), rotation of the worm 115 rotates the sprocket 88 through the chain 97 and winds up the spring 87 through the gear 91 and spindle 85, the worm 115 moving axially against the spring 118 when the spring 87 is fully wound and disconnecting the friction drive 117. On release of the table 3 by rotation of the drum 34, the sprocket 88 uses the chain as a rack and moves the frame 84 along the guides 82, 83, carrying the table 3 and work with it until the next stop 36 &c. engages the drum 34. Rotation of the eccentric 86 on the spindle 85 is prevented by a rectangular key 92 on the eccentric engaging between pivoted dogs 94, 95 on a slide 93 movable in the frame 84, the dogs 94, 95 being pressed outwards by springs 96. When the slide 84 approaches the rearward end of its travel an adjustable fixed stop 103 on the bearing 101 engages the slide 93 and moves it relatively to the frame 84 until the dogs 94, 95 ride off the end of the key 92, thereby allowing the spring 87 to rotate the eccentric 86 through half a revolution and moving the sprocket 88 from engagement with the upper run of the chain 97 into engagement with the lower run. In this position the key 92 snaps between the dogs 94, 95 again and locks the eccentric against rotation. The spring 87 then unwinds to drive the sprocket and traverse the frame 84, rod 29 and table 3 in the reverse direction back to the starting point. In order to cushion the stoppage of the table 3 &c. at each end of the traverse, a brake is provided comprising a shoe 110, Figs. 1 and 5 (10659/36), carried by two links 108 pivoted at 107 to the frame 84. A rod 105 is slidable in the frame and carries two rigid arms 106 connected by springs 111 to the links 108. At each end of a traverse the rod 105 engages one of the adjustable fixed stops 113, 114 on the bearings 100, 101, thereby rocking the links 108 through the springs 111 and applying the shoe 110 to the underside of the guide 83 to stop the traverse.