Patent GB-259451-A (GB)
IPC: A46D3/02
Abstract: 259,451. Rabinovitch, I. Feb. 22, 1926. Drilling brush stocks.-In a multiple-spindle machine for drilling brush stocks of wood, bone, celluloid, metal &c. of the kind wherein each spindle drills a hole in a stock and the latter is then moved to the next station for the drilling of an adjacent hole, the stocks being mounted on a horizontal work-holder intermittently rotated beneath vertical drills and moved vertically for each drilling operation, the drills are all driven from a single shaft and the stocks are adjusted angularly for drilling inclined holes at each vertical reciprocation. In one form of machine the brush stocks 17, Fig. 1, are mounted on a turret 21 slidable vertically and rotatable about a central column 4, and the drills 8 are adjustably carried by a fixed plate 2. There are as many drills as there are holes required in the finished stock and each is separately driven by bevel gearing 9, a flexible shaft 10 and gearing 12 from a central shaft 14 rotated by a belt pulley 15. The drill heads 7 are rotatably adjustable about bolts 6 which are radially adjustable along slots 5 in the plate 2. The turret 21 is rotatable on a flanged plate 20 which is slidably keyed to the pillar 4 and is raised slowly and lowered quickly to feed the work to the drills bv two cams 18 rotated from a common worm 25 on the shaft 14 and engaging rollers 19 on the plate. Intermittent rotation of the turret to feed the stocks from one drill to the next is produced by one or more pawls attached to an eccentric disc driven from the worm 25 and engaging teeth formed on the interior of a flange 30 attached to the turret, locking being effected by a second pawl or pawls also engaging the annular teeth and oscillated by a cam on the eccentric shaft. Both pawls follow the upward and downward movements of the turret and all the gears are protected from dust and shavings. For drilling inclined holes each stock is mounted on a carrier 35, Fig. 5, oscillatable about perpendicular shafts 24, 46, by means of levers 36, 37 and cams 42, 43 adjustably secured to an annular casing 47 slidable on the vertical pillars 3 of the machine together with the turret. The lever 36 is secured to the shaft 26 to oscillate the carrier directly and the lever 37 oscillates a cam 44 producing the movements about the shaft 46. The cams 42, 43 are set by means of an inclinable surface which is mounted in place of the drills and is made to contact with each carrier in turn. A stop motion may be provided which automatically stops the whole machine after each hole has been drilled to allow a finished stock to be removed and a new one to be inserted on the turret, and a pedal may be provided for stopping the machine at any intermediate instant. In a modification a plate 58, Fig. 7, carrying the drill heads 89 and the turret table 21<1> are both moved vertically on a central pillar 57 by means of two or more cams 65, 67 driven from the central shaft 14' and so designed that the downward movement of the drills is greater than that of the work to effect the drilling feed. The drills are driven by flexible shafts 91 and gearing 92 from a shaft 14<11> connected to the shaft 14' so that a casing 57<1> together with the gears may be removed as a unit. Each drill head is mounted for adjustment on two perpendicular guides 90, 90<1> arranged radially and tangentially respectively. The plate 58 and a boss 59<1> on which the turiet is rotatable are guided vertically by rods 70 secured to the pillar 57. springs being provided on the rods to cushion the downward movements of the turret. The intermittent rotation of the turret is produced by a worm 76 continuously rotated through gearing 71, 74 from the main driving shaft 56, the worm rotating on a stationary axis and engaging a circular rack 77 on the turret when the latter is raised and the drills have been withdrawn from the work. Indexing is effected by a finger 78 attached to the turren passing into the vertical slots between stationary plates 70 when the turret is lowered. The brush stocks B, Fig. 12, are pivoted about two perpendicular axes 83, 84 and are held in frames 82 by pivoted clamps 87 actuated by cams and a hand lever 88. The frames are maintained normally in horizontal position by springs 85, 86 but are adapted to be tilted by pins 94, Fig, 7, each time the turret is lowered. The pins are arranged in sets of three for each drilling position and are individually adjusted by screws 94<1> and a crank 112. A device to facilitate such adjustment comprises a plate 102, Fig. 15, oscillatable about two perpendicular axes 103, 104 under the control of scales and pointers 105, 107 and locked in the adjusted angular position by wing nuts 110, 111. The device is mounted on a hollow shaft 99 carried by a bracket 96 which is attached to each drill head in turn by means of a dove-tailed groove 95, Fig. 7. In the operation of this device the plate 58 is fed downwards with the bracket attached to a drill head until the inclined plate 102 contacts with the corresponding work frame, a spring 100 and pin 101 allowing the plate to yield slightly, and the pins 94 are then adjusted to contact with the frame. In a modification of the drill heads the flexible shafts 91 may each rotate a bevel gear 133, Fig. 18, gearing either with an annular gear 135 or with a spur gear which rotates a number of pinions 136 each attached to a separate drill spindle. The gearing is enclosed in a casing which permits lubrication of the mechanism and adjustment of the spacing and arrangement of the drills. In a further modification the drill spindles are arranged in a single line and the work holders are mcunted on an endless chain intermittently traversed under the drills by two rotary drums and supported by a fixed table, the adjustments described in connection with the other machines being also provided. Mounting chucks.-To facilitate changing the drills the spindle 137, Fig. 19, which is driven by a flexible shaft 91, is connected to the chuck by a joint 138 and a removable sleeve 139 maintained in driving position by a pin 140, so that on removing the pin and sleeve the chuck may be rotated into a horizontal position. Clutch-operating mechanism ; stop motions.- The machine is arranged to be stopped completely after each reciprocation of the drill heads to allow a fresh blank to be inserted or. the turret and a finished one to be removed by means of a clutch 55, Fig. 9, on. the main driving shaft 56, operated by a lever 128 connected to a rod 126 in contact with a cam 124. The cam is rotated intermittently by a pawl 122, a ratchet wheel 123 and gearing 119, 116 from a worm 114 on the shaft 56 so as to keep the clutch in the engaged position until a sharp incline allows a spring 129 to open the clutch. The clutch may also be opened at will by means of a pedal connected to a rod 131 which operates a second pawl 132 engaging the ratchet wheel 123.