PORTABLE TOOLS AND HANDLES THEREFOR

Abstract: A handle for a portable tool has secured to it spindle 15 which is engageable in a nut 12 held captive in the tool casing. The spindle is encircled by a flange 18 having on one face ratchet teeth 27 which co-operate with complementary teeth 26 in a boss 25 on the casing, the flange being capable of axial movement relative to the spindle 15 against the bias of a spring 24 to allow the teeth 27 to ride over the teeth 26. The handle cannot become unscrewed accidentally but can be unscrewed when the flange is pressed outward against the spring 24.

Description: PORTABLE TOOLS AND HANDLES THEREFOR This invention relates to portable tools and handles therefor. Portable tools, especially portable power tools, may be provided with an auxiliary handle, for example for steadying the tool, and these auxiliary handles, which are generally screwed into position on the tool, are prone to coming loose. According to this invention there is provided a portable tool having on the external casing thereof a socket which is internally screw-threaded or which holds a nut captive therein, and a handle comprising a grip portion, a screw-threaded spindle projecting from the grip portion and engageable in the nut or screw-thread in the socket, characterised in that a locking member is engaged on the spindle so as to be non-rotatable relative to the spindle but spring-loaded so as to be movable axially relatively to the spindle from an end position in a direction towards the grip portion, said locking member being spring-loaded into said end position, the locking member and the part of the casing member about the socket being provided one with one or more axially-facing ratchet ramp faces extending about the axis of the screw-thread and the other with one or more surfaces which co-operate with the ratchet ramp face or faces to permit the locking member and spindle to be screwed into the socket or nut, the ramp face or faces riding over said surface or surfaces and deflecting the locking member axially against the spring-loading but to prevent unscrewing movement of the spindle. in one embodiment of the invention the locking member comprises a disc-like element with teeth along its circumference the leading portions of the axial end of the teeth nearest the socket being chamfered to form said ramp faces, and the said co-operating surfaces are formed on the internal cylindrical surface of a hollow boss on the casing and are in the form of teeth of complementary circumferential profile to those on said disc-like element. One embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a view in elevation, and partly in section, of the handle and co-operating part of the casing of a portable tool according to the invention, Figure 2 is a view similar to Figure 1 showing the handle in position on the tool casing, :: Figure 3 is a perspective view corresponding to Figure 1 of the handle and co-operating part of the casing, and Figure 4 is an end view of the handle in the direction of the arrow X in Figure 3. Referring to Figures 1 and 3 of the drawings a portable power tool has in its external casing 10 a socket 11 in which a nut 12 is held captive. A handle 13 for attachment to the casing comprises a grip portion 14 from one end of which projects a screwthreaded spindle 15 fixed to the grip portion. The grip portion is formed with an annular recess 16 in its end adjoining the spindle. The recess accommodates an annular stem 17 with which is formed integrally a handle flange 18, and the recess is of sufficient axial length to permit a degree of axial movement of the flange 18 and stem 17 relative to the grip portion. A toothed locking element 20 is fixed to the flange and is in axial abutment with an enlarged portion 22 of the spindle. This portion of the spindle has two flats 23 on its periphery which are accommodated in a recess in the locking element 20 and which serve to prevent rotation of the flange 18 and element 20 relative to the spindle. A compression spring within the recess 16 loads the flange and element into their end position of abutment with the enlarged portion 22. The surface of the casing about the socket is formed with a hollow boss 25 the internal cylindrical surface of which is formed, over half of its periphery, with teeth 26 complementary in circumferential profile to the teeth 27 formed on the external surface of the element. However the leading edges of the axial ends of the teeth of the element are chamfered to form ratchet ramp faces 28. To secure the handle in position, the spindle 15 is screwed into the nut 12. When the ramp faces 28 of the teeth 27 contact the edges of the teeth 26 in the boss, the flange and element are forced outward away from the casing in ratchet position, the spring alternately permitting the flange 18 and element 20 to move outwardly away from the shoulder and pushing the element back against the shoulder on the spindle portion 22. The enlarged portion 22 of the spindle is arranged to come into tight abutment with the casing before the ramp faces of the element are fully accommodated within the toothed portion of the boss, and the unchamfered edges of the teeth on the element 20 then prevent unscrewing of the gripping element 14 and-spindle 15. To unscrew the handle the element is first disengaged from the teeth in the boss 26 by moving the flange 18 against the force of spring 24; the handle can then1 bye unscrewed. The handle is thus held secure against accidental loosening by vibration or manual force applied to the handle during operation of the tool, but can readily be removed when desired.

Claims: CLAIMS 1. A portable tool having on the external casing thereof a socket which is internally screw-threaded or which holds a nut captive therein, and a handle comprising a grip portion, a screw-threaded spindle projecting from the grip portion and engageable in the nut or screw-thread in the socket, characterised in that a locking member (20) is engaged on the spindle (15) so as to be non-rotatable relative to the spindle but spring-loaded so as to be movable axially relatively to the spindle from an end position in a direction towards the grip portion (14), said locking member being spring-loaded into said end position, the locking member (20) and the part of the casing member (10) about the socket being provided one with one or more axially-facing ratchet ramp faces (28) extending about the axis of the screw-thread and the other with one or more surfaces (26) which co-operate with the ratchet ramp face or faces to permit the locking member (20) and spindle (15) to be screwed into the socket or nut (12), the ramp face or faces (28) riding over said surface or surfaces (26) and deflecting the locking member axially against the spring-loading but to prevent unscrewing movement of the spindle. 2. A portable tool as claimed in claim 1 characterised in that the locking member (20) comprises a disc-like element with teeth (27) along its circumference the leading portions of the axial end of the teeth nearest the socket being chamfered to form said ramp faces (28) and the said co-operating surfaces (26) are formed on the internal cylindrical surface of a hollow boss (25) on the casing (10) and are in the form of teeth of complementary circumferential profile to those on said disc-like element. 3. A portable tool as claimed in claim 1 or claim 2 characterised in that the handle (14) is formed with a recess (16) in its end adjoining the spindle, said recess accommodating a stem (17) formed integrally with the locking member and being of sufficient axial length to permit a degree of axial movement of the locking member relative to the handle, and a compression spring (24) being disposed within said recess to bias said locking member into said end position. 4. A portable tool as claimed in claim 3 characterised in that the recess (16) and the stem (17) are both annular. 5. A portable tool as claimed in any one of claims 1 to 4, characterised in that a radial flange (18) projects outward beyond and is fixed to the locking member (20) at the axial side thereof remote from the spindle (15), for which flange is engageable to press the locking member against the bias of the spring-loading.

Inventors: FORD, LESLIE WALTER
Applicants: KANGO LIMITED
Application year: 1984
Main classification: B25G3
IPC codes: B25F5, B25G3