GB649317A - Improvements in or relating to wrenches, spanners and like gripping tools for effecting rotation of a workpiece - Google Patents

Abstract

649,317. Screwing-up nuts &c. TOMLINSON, K. H. Oct. 12, 1948, No. 26502. [Class 83 (iii)] A wrench, spanner or the like for effecting rotation of nuts and other workpieces comprises a rotary shaft or cable which passes through or along the handle of the device for transmitting the drive from a drive unit which may or may not be mounted on the handle, a clutch positioned along the shaft or cable for permitting disengagement of the drive or limitation of the torque transmitted therefrom to the workholder which has its axis angularly disposed to the axis of the handle, and locking means embodied in the drive from the clutch or incorporated between such drive and the tool body whereby, when desired, rotation of the handle about the axis of the workholder serves to rotate the workpiece. As shown in Fig. 1, the inner shaft of a flexible cable transmits rotation from a drive unit to a shaft 32 located within the handle 5 and this drive is then communicated to a member 12 rotatable in a casing 1 through a spring- controlled friction clutch 15, 18 and bevel gearing on the parts 12, 15. The casing 1 and handle 5 are connected by a tube 3 enclosing the clutch 15, 18 and are each formed in halves connected by screwed rings. A spindle 6 for the attachment of the workholder is rotatable in the casing 1 and has clutch teeth on its upper end for engaging with similar teeth on the lower end of the member 12. The spindle 6 is slidably guided in the casing by a pin 10 and is normally urged downwardly by a spring 13 so that the relevant clutch parts are disengaged. In this position of the spindle, ratchet teeth on the latter are engaged by, either of two 'spring-pressed pawls 38, 41, Fig. 3, which are under the control of an handoperated cam 29. The clutch parts 15, 18 are urged together by a spring 20, the pressure of which may be adjusted either by a screwed ring or a rod 28 in screw-threaded engagement with an adjusting nut 27 ; a visual indication of the spring pressure may be provided by a nut fixed on the rod 28 and movable in a slot in the tool body. In a modification, the locking device comprises a spring-loaded plunger engaging a toothed wheel on the spindle 6. In the modification shown in Figs. 4 and 6, the work-holder spindle 68 is connected to a flexible driving shaft 56 which passes through a curved tube 52 and at its opposite end is keyed to a driven clutch member 80 in the handle 53. The other clutch member 92 is connected to a main drive shaft 81 and is slidable in the handle, being urged forwardly by a spring 87 so that the angular teeth on the two members become disengaged at a predetermined torque. A pawl. 67, which is normally retained by a spring out of engagement with ratchet teeth on the spindle 68, is pushed forward to engaged position by two spring-controlled push rods 61, 62 when a thumb lever 77 is depressed. Depression of a second lever 78 slides the clutch member 92 into disengaged position. These two levers may be interconnected so that, when the locking device is engaged, the clutch is disengaged, or the lever for disengaging the clutch may, itself, engage a toothed wheel on the spindle 68. When the drive is by a flexible cable, reduction gearing may be provided in addition to the gearing necessary to give the desired angular relationship of the work-holder. If desired, the gearing employed between the clutch adjacent the handle and the work-holder may be such as, itself, to constitute the locking means, being in the form of a worm driving a worm wheel and arranged so that no rotation of either is possible unless the worm is first actuated ; to provide for free rotation of the work-holder, a ratchet device is interposed between the worm wheel and work-holder or one or two pawls are arranged to engage the teeth of the gearing. The Provisional Specification describes also the locking device and clutch as being disposed in the handle, the provision of a shroud for protecting the clutch and adapted to be pressed by a hand lever against the female member of the clutch so as to slide the latter into disengaged position, and the use of this lever for engaging a locking wheel on the driven shaft in the handle to constitute the locking means ; a sliding catch on the lever co-operates with a projection on the handle for holding both the clutch and locking device out of engagement.