RATCHET SPANNER

Abstract: An open-ended ratchet-type spanner has a head (1), two opposite jaws forming an opening or mouth for receiving a nut or other workpiece (3), and having within its mouth a moveable element (4) which is biased towards the workpiece and reciprocally engages with the workpiece during alternate torque and ratchet strokes executed by the spanner. The geometry of the arrangement being such that during a torque stroke, when the element is engaged with the workpiece, forces are transmitted from the jaw (5) through the element to the workpiece and cause said element to become trapped against the jaw adjacent thereto, and the workpiece becomes subjected to torque-producing forces at faces (9 and 10). When the spanner is turned in the reverse direction for a ratchet stroke, the element is displaced by vertices of the workpiece allowing the spanner to rotate around the workpiece for a successive grip.

Description: Ratchet spanner The invention relates to spanners , in particular open-ended spanners having a ratchet-like action for manual use or for use by robots . Socket spanners and ratchet ring spanners and such like are merited over open-ended spanners for being easi er to use and quicker in operation, ϊnere are , hov/ever, situations wherein ratchet spanners of the type mentioned cannot be used, such aε on a pipe connection, the nut being only accessible to an open-ended type spanner which is slow in operation because it has to be removed from the workpiece and realigned before it can be located on the next pair of flats . Providing an open-ended spanner v.ith a ratchet-like action almost certainly requires there to be at least one moveable " element within the j aws which will engage γ_Lth the Y/orkpiece during a torque stroke . The problem v.ith having such torque transmitting move able elements is hoγ/ to prevent the tendency for them to slip out of engagement vdth the workpiece before a torque of useful magnitude can be imparted thereto . ϊhe invention as claimed is entended to solve these drawbacks . I t solves the problem of how to design an open-ended spanner having a oveable element which reciprocal^ engages v.ith a nut or other workpieGe during alternate torque and ratchet strokes , said element resisting the tendency to slip out of engagement with the workpiece during a torque stroke by utilising the forces generated between the reciprocating element and the workpiece to hold said element firmly in position against the adj acent j a with which it mates ; and also utilising the forces generated between the reciprocating element and v/orkpiece , during a ratchet stroke, to displace sai d element and thereby allow BAD ORIGIN ratcheting or relative rotation of the spanner around the workpiece; hence alternating torque and ratchet strokes executed by the spanner effectuate uni-direct- ional rotation of the workpiece. The advantages offered by the invention are mainly that when turned in one direction it v.ill impart torque to a v/orkpiece located within the mouth thereof* and the moveable element resists being forced out of its engaged position with the workpiece, and when turned in the opposite direction the invention will impart no torque of any significance to the workpiece as the moveable element becomes displaced out of its engaged position. Inherent in the design is the quality that, during a torque stroke stroke, increasing torque causes increasing stability of the moveable element. One v/ay of carrying out the invention is described in detail belov; with reference to drav.ings which illustrate only one specific embodiment, in which: Figure 1 is a side view of the spanner in accordance v.ith the invention. Figure 2 is a semi-transparent perspective view corresponding to Figure 1. The figures show a spanner comprising a head (1) having two opposite jaws (5 and 12) forming an opening or mouth for receiving a nut or other workpiece (3). The spanner has a handle (2) which may be detachable from the head. A moveable element (4) resides at one side of the mouth, and in this embodiment said element is bifurcated producing tv/o arms which locate over the adjacent jaw ( ). The jaw may be reduced in thickness compared with the remainder of the head. The arms of the moveable element are secured to the jav/ by means of a pivot pin (6) and a coil spring (7) biases said element towards the workpiece by acting on the arms thereof. The pivot pin passes through the coil spring BAD ORIGI .n an both locate in a hole running through the thickness of the jav/ ( ). The coil spring has a reaction lobe, see (7s) in Figure 2, to prevent rotation thereof. The reaction lobe locates in a Becond hole (5a), in the jaw, adjoining the first hole perpendicularly. In the mouth of the spanner there is a recess (P) which allows freedom of movement to the reciprocating element. Stop means may be provided to limit the travel of the element. The spanner can be introduced to the workpiece without opposing flats of the workpiece having to be parallel to the jaws. When the spanner is turned in the direction of arrow T in Figure 1, for a torque stroke, the flat face (9) of the nut pushes the element towards the jaw (5), shaped so that said element locks therewith. In this position the element cannot disengage with the nut, and therefore the nut becomes gripped between the element and the other jaw and torque-producing forces are applied to the nut at faces (y and 10). When the spanner is turned in the direction of εrrov/ E in Figure 1, for a ratchet stroke, tiie vertex (11) of the nut induces the element to displace with a cam-like action into τhe recess (8), thus alloying the spanner to ratchet around the nut for ε successive grip, ϊo turn the nut in the reverse direction, the spanner can be turned over. In further modifications of the invention the moveable element (4) may have a single arm positioned centrally so that it locates in a bifurcated jaw. The invention may also have one or more moveable elements. BAD ORIGINA

Claims: Claims : 1. A ratchet-type spanner comprising a head (1) having two opposite jav.'S (5 and 12) foaming an opening or mouth for receiving a nut or other workpiece (3), a moveable element (4) residing at one side of the mouth 5 reciprocally engages v.ith the workpiece during alternate torque and ratchet strokes execute:! by the spanner, characterised in that the mating surfaces of the element and adjacent jaw are so shaped that during a torque stroke said element becomes trapped in its engaged 0 position with the workpiece, thereby causing mutual locking of both element and workpiece betv/een the jav/s, the geometry of the arrangement being such that during a torque stroke the forces generated betv/een workpiece and element are transmitted through said element to the 5 adjacent aw, and during a ratchet stroke the forces generated between workpiece and element impart displacement to said element allowing ratcheting or relative rotation of the spanner around the workpiece, and by these means, alternating torque and ratchet .0 strokes executed by the spanner effectuate uni- irect¬ ional rotation of the workpiece. 2. A ratchet- ype.spanner as claimed in claim 1, wherein the moveable element (4) is attached to the adjacent 5 jaw (5) by means of one or a pair of arms. 3. A ratchet-type spanner as claimed in claims 1 or 2, wherein the moveable element (4) is pivotally mounted on the adjacent jaw (5). 0 4. A ratchet-type spanner as claimed in claims 1,2 or 3, wherein a means is provided to bias the position of the moveable element. 355. A ratchet-type spanner as claimed in claim 4, wherein the position of the moveable element is biased by means of ε spring. BAD ORIGINAL 6. A ratchet-type spanner as claimed in any preceding claim, wherein there are one or are moveable elements.

Inventors: MAGILL LAWRENCE, MAGILL, LAWRENCE
Applicants: MAGILL LAWRENCE, MAGILL, LAWRENCE
Application year: 1985
Main classification: B25B13
IPC codes: B25B13