GB1357715A - Rock drill equipment device for mechanized drill bit exchange - Google Patents

Abstract

1357715 Unscrewing drill bits from drill rods LINDEN-ALIMAK AB 8 Feb 1973 [8 Feb 1972] 6275/73 Heading B3N A device for exchanging a drill bit 8 on a drill rod 3 comprises a magazine 4 for delivering the bits and means for effecting relative rotation between the rod and bit for screwing the bits on and off the rod. The magazine 4, Fig. 1, may consist of a rotatable cartridge 5 having a number of rubber holders 7 for storing and holding the bits and a device 21 for stepping round the cartridge about an axis 6. The drill frame 1 may be provided with an arm 11 pivotable about an axis 10 by a piston unit 13 from the position shown by dash-dotted lines to the operative position where a wrench member 14 contained in a casing 15 can be applied to the drill bit. When a drill bit is to be exchanged, the drill rod 3 is retracted to the left until the old bit 8 enters the empty rubber holder 7. The arm 11 is then swung up so that the wrench member 14 engages the bit by its projections 20, Fig. 2. The drill rod 3 is then rotated so that the bit is screwed off and retained within the casing 15, a wrenching action being brought about by projections 18 on the wrench member 14 striking stop members 17 on the casing. The drill rod 3 is then retracted clear of the rubber holder 7 and the old bit pushed back into the holder by a piston unit 16. After the arm 11 has been swung out of the way, the cartridge 5 is stepped round to present a new bit 8 to the drill rod which is rotated and fed forwardly into the bit as it is held by its rubber holder 7. Alternatively, the drill bit may be arranged to rotate instead of the drill rod for screwing purposes. Instead of being mounted on the drill frame 1, the device may be mounted on the rack wall. In another embodiment, Figs. 3 to 5 (not shown), the magazine (30) may consist of a casing (37) having an aperture (36) for the drill rod (3), a wrench member (40) and a piston unit (46), the casing being pivotable about an axis (48) to bring the aperture opposite the drill rod. The magazine may contain a cartridge in the form of a chain which runs over sprocket wheels (34, 35), the drill bits being held by arms (31) secured to the links of the chain; the arms automatically release the bit adjacent the lowermost sprocket. When a drill bit is to be exchanged, the drill rod (3) with the old bit is pushed through the aperture until the bit is engaged with the wrench member (40). The drill rod is then rotated to screw off the old bit and is retracted from the magazine. The hold bit is pushed by the piston unit (46) into the empty space between a pair of arms (31) on the chain before the chain is stepped round by a device (47) to bring a new drill bit into place. The drill rod is advanced again through the aperture to push the new bit into engagement with the wrench and the drill rod then rotated to screw the bit on. The drill rod with bit is then withdrawn and the magazine pivoted clear.