GB1357007A - Power tool - Google Patents

Abstract

1357007 Power tools GKN SCREWS & FASTENERS Ltd 26 April 1972 [21 April 1971] 10374/71 Headings B3N and B3C [Also in Division F2] A power tool comprises a body, two holders for mounting work implements in axially opposed directions, power means in or on the body, guard means on the body for guarding the implement not in use when the other implement is in use and means for moving the guard means relatively to the holders to bring one of the holders into its operating position while the other holder is in a position where its implement is within the region of protection of the guard means. In the embodiment shown in Fig. 1 the body comprises an outer sleeve 10 axially slidable on an inner sleeve 11. The body is rotatable upon a handle 14 in which an air motor 16 is mounted. Sleeve 10 has a plate 35 fixed thereto which plate has an aperture with a toothed rack 21 formed on one side which engages a gearwheel 20 fixed to an outer housing 15 of the handle. Thus rotation of the body about the handle causes the outer sleeve to move axially of the holders 22, 23 to expose one implement and provide a guard for the other. Plate 35 has a slot at each end, one side of the slot being longer than the other side. A trigger in the form of a bar 29 has a projection 37 adapted to engage the slots. As shown the projection abuts the long side of the slot and thus acts as an indexing stop during rotation of the body. Operation of the trigger causes the projection to fully enter the slot and thus lock the body to the handle. A U-shaped yoke 31 is attached to bar 29 and acts to operate a plunger which activates an air inlet valve when the trigger is operated. Fig. 5 shows a second embodiment with a single guard member 46. An intermediate body portion can swivel on a bearing pedestal 45. Location of the body and locking of the body to the handle is achieved by a nose 50 on the trigger mechanism engaging in slots 51. Fig. 7 shows a third embodiment in which a housing 60 is mounted on a swivel tube 70. The tube contains an air valve mechanism 72 that is rotatable therewith about the axis of handle 71. At each end of the body there are guards that comprise inner and outer sleeves. The inner sleeve has to be manually moved to expose an implement and is held in an inner position by a metal strip 83. When the body is rotated the inner sleeve is automatically released and spring biased to its outer position. In the reverse position the inner sleeve is held against movement by a lug 95.