Patent GB-334694-A (GB)
Title: Improvements in and relating to radial-arm drilling machines
IPC: B23Q1/30
Filed: 1929-08-23
Abstract: 334,694. Cincinnati Bickford Tool Co., and Klausmeyer, D. C. Aug. 23, 1929. Drilling-machines. - A radial-arm drilling-machine has the verticallyadjustable arm clamped to the pillar by two clamps at opposite sides of the pillar, that near the drill-head being at the top of the clamping sleeve and the other at the bottom and a handlever is provided for operating the clamping nuts simultaneously and also for actuating a power drive for raising or lowering the arm. The hand lever is so connected with the clamping and traversing means that both cannot be in operation simultaneously. In one form of machine the radial arm 3, Fig. 1, formed integral with a sleeve 2 is slidable on the vertical pillar 1 by means of a rotatable screw 4 co-operating with a stationary nut on the arm. A central spindle 7, Fig. 2, in the pillar, rotated in any manner, carries a wide gear 9 engaging a gear 11 on a stub shaft 12 which carries a gear 15, either the gear 9 or the gear 15 being adapted to drive a pinion 10 so as to rotate the screw 4, through a gear 18, in one direction or the other. The pinion 10 is carried by a lever 17 oscillated by a toothed sector 19 thereon meshing with a similar sector 20 secured to a vertical shaft 21 journaled on the pillar. A sleeve 31, Fig. 1, loose on the shaft 21 carries a hand lever 30 provided with a spring plunger 32, controlled by a trigger 37, and also carries two spiral gears 50, 51 engaging toothed sectors 47, 48 secured to the nuts on the clamping bolts 39, 40. These bolts are arranged as shown in Fig. 1 in order to clamp the sleeve 2 to the pillar at the points where the weight of the arm 3, drill-head &c. tends to separate them, and the bolts are prevented from rotating by feathers thereon engaging slots in the sleeve. In operation, the trigger 37 is raised to remove the plunger 32 from a notch in a collar 25 secured to the shaft 21, thereby permitting lever 30 to be moved towards the arm 3 to cause the sleeve to be locked to the pillar without affecting the shaft and the power traversing means. If one bolt should lock before the other the sleeve 49 carrying the skew gears will screw axially on the stationary sector and so equalise the pressure between the two bolts. On moving the lever 30 away from the arm the sleeve is first unlocked and the plunger 32 then enters the notch in the collar 25. thereby coupling the lever to the shaft 21 and allowing either of the gears 9, 15 to be meshed with the pinion 10 to raise or lower the arm 3. To disconnect the power traverse the plunger 32 is withdrawn from the collar 25 whereupon the reaction between the teeth of the gears 9 or 15 and 10 oscillates the lever 17 to a neutral position in which it is locked by a spring detent 22, Fig. 1. The lever 30 may then be moved to clamp the arm. Stops 33, 34, Fig. 2, on the sector 20 engage adjustable screws 35 to limit the movement of the lever 17 in the driving positons and stops 55, 56 on the sleeve 2 are adapted to engage cams 52, 53 on the sleeve 31 so as to rotate the latter and disengage the drive when the arm 3 reaches its upper or lower limit. The drill spindle is driven from a shaft 14 rotated from the gear 11. In a modified machine the arm 3, Figs. 5 and 7, is traversed by a stationary screw 65 secured to the pillar and a nut 66 rotatably journaled in the sleeve 2. The nut 66 carries two gears 85, 86, which are adapted to be coupled alternatively to a gear 77 either directly or through an idler 87 to rotate the nut in one direction or the other. The drive is instituted by moving the gear 77 axially on its shaft 64, a sleeve 76 attached to the gear being provided with cam surfaces 81, 82 which act on a lever 78 to expand a friction band 75 and clutch the gear to the shaft after the teeth have been placed fully in mesh. The shaft 64 is driven through gearing 61 from the shaft 7, located in the pillar, and the gear 77 is moved axially by an arm 100 on a shaft rotated by bevel gearing 98 from a vertical shaft 96 which is connected by toothed sectors 95, 94 to the hand-operated shaft 21. The machine may be driven by a motor at the base of the pillar or on an extension of the arm, and in the latter case the shaft 64 is rotated through bevel gearing 103 and a shaft 102 journaled on the arm. Feed-screws and nuts.-A ball bearing 68, Fig. 5, takes the thrust of the nut 66 and a second inoperative nut 69 is provided on the stationary screw 65 to support the arm 3 if the nut 66 should fail. Framings and supports. - The sleeve 2 is strengthened at the top side opposite to the arm 3 by means of a rib 3b, Fig. 7, merging into the sleeve at 3<c>.