GB167286A - Improvements in and relating to electric operated hammers - Google Patents

Abstract

167,286. Kollock, S. W. M. May 4, 1920. Percussive hand tools.-In a motor-driven percussive hand tool, a two-part cylindrical casing having a handle with a switch is provided with perforated transverse members to support the motor spindle axially in line with a spring-operated plunger which carries at its inner end a yoke engaged by tappets on a disc rotated by gearing mounted in the casing. The current to the motor 13 is controlled by a plug switch 20 in a hand grip 11 secured to a two-part casing 10, and a fan 21 is provided on the motor shaft 14 to keep the parts cool. The motor shaft is mounted in transverse members 15, 16 which is perforated for ventilation purposes. On the motor shaft outside the member 16 which connects the two parts of the casing is fixed a bevel-pinion 22, which through bevel-wheel 23 and spur gear 25, 26 rotates a. tappet member consisting of two discs 26<a>, 26<b> carrying bushed tappets 32<a>. The tappets in turn engage the part 33 of the yoke 27 of a plunger 28 pressed forward by a spring 31, a cushion spring 34 on the yoke relieving jar. The outer sides of the yoke are channelled to engage guide ribs 44 on the casing. In a modification, the yoke consists of a U-shaped member, Fig. 5, provided with contact members in the form of sleeves 37 engaged by tappets on each side of a single member 36. In the form shown in Fig. 7, a divided yoke of the form shown in Fig. 2 is engaged by sleeve tappets 41 on each side of the tappet member 39.