GB665920A - Improved drill - Google Patents

Abstract

665,920. Driving. HOUILLERES DU BASSIN DU NORD ET DU PAS-DE-CALAIS. Jan. 25, 1949, No. 2000/49. Class 83 (iii). [Also in Groups XXI and XXIII] A machine for drilling tunnels and the like comprises a number of bits 50a ... 50d mounted rotatably in heads 49a ... 49d, carried by arms 46a . . . 46d, supported by a carriage 34 that can be fed along its longitudinal axis XX which is parallel to the bits, and a control means for adjusting individually or simultaneously the pitch of the bits from the axis XX. The carriage 34 is mounted rotatably on bearings 33, Fig. 6, on a shaft 26 supported in a yoke 10, 11, Fig. 1, which is mounted on a carriage A fitted with wheels 3 adapted to be locked by a wedge 6 when the carriage has been transported on tracks 4 to the work face 5. The yoke 10, 11 may be fed along slideways 8 on the carriage A by an electric motor 13 driving through a reduction gear 14, and pinions 15, 17 on to a rack 18, or it may be fed by hand-operating an additional rack and pinion disposed on the side of the carriage opposite the rack 18. At the ends of traverse of the yoke 10, 11, adjustable projections 19, 20 on the carriage A contact switches 21, 22 on the yoke in order to reverse the direction of rotation of the motor 13. A rod 35 bearing in a lug on the carriage 34 and projecting through arcuate slots 37, 38 in the yoke 10, 11 is adapted to adjust the angular location of the carriage against a scale (not shown) provided on the forward face of the yoke member 11. The rod 35 is preferably secured releasably by means of a lever 42 to the shaft 26 and provided with a hand-operated pinion 39 which co-operates with a toothedquadrant 40 fixed on the yoke-member 10 so that after releasing a locking-nut 41 on the rod 35 and turning the pinion 39, the rod may be traversed laterally in the slots 37, 38 in order to turn the carriage 34 and shaft 26 about the axis XX. The bits 50 are rotated by compressed air motors and supplied with water along leads 52 to clear chips from the drill holes. The arms 46 which support the bits are inclined to the axis YY of the polygonalshaped carriage 34 and received slidably in recesses 45 provided along the edges thereof behind cover-plates 47. A pinion 53, Fig. 6, keyed at 54 to the shaft 26 meshes with pinions 55 which engage rack teeth 57 formed along the arms 46 so that when a locking screw 44, Fig. 1, on the lever 42 is released, the shaft 26 may be turned to adjust simultaneously the radius of the bits from the axis XX. The shaft 26 is turned by a hand-controlled gear 28 meshing with a pinion 27 which is keyed to the shaft, an indexing-bolt 31 being provided to lock the pinion 27 in adjusted position and screws 64 for engaging slots 63 formed in the arms 46 so as to lock the latter following adjustment in the recesses 45. Individual adjustment of the radius of the bits 50 is effected by displacing axially, by means of its knob 62, Fig. 6, a shaft 59 on which the pinion 55 is keyed, through a distance sufficient to engage a groove 61 in the shaft 59 with the outer of two spring-rings 60 and disengage the pinions 53, 55, and then turning the knob. Stays 67, Fig. 8, pivoted at 69 to a collar 70 on the-shaft 26 and provided with adjustable pawls 66 to engage notches 65 in the arms 46, may be provided to support the bits 50. A central bit 71 secured in the shaft 26 may also be provided.