US 2978081 A
Description (OCR text may contain errors)
April 4, 1961 D. M. E. LUNDIN DEVICES IN RATCHET WRENCHES Filed July 24; 1957 JNVENTOR DAVID MAURITZ EMANUEL LUNDIN ATTQRNEYS United States Patent nnvrcns IN RATCHET WRENCHES David Mauritz Emanuel Lundin, Enkoping, Sweden, as-
signor to Aktiebolaget Bahco, Stockholm, Sweden, a corporation of Sweden The present invention relates to a device in such ratchet wrenches wherein the operation direction of the ratchet wrench may be reversed by means of a pawl device which can be reset by hand, and the object of the invention is primarily to enable the width of the ratchet wrench head to be reduced so that the ratchet wrench can be used in very confined spaces. Furthermore, by the invention it will be possible to obtain an efficient rotating of the, work piece, usually a screw bolt, drill or the like, by very short strokes and the invention is characterized in that the pawl device comprises one or two pawl members freely journalled in a rocker pivotably carried in the wrench head, the pawl member or members being provided with, or each being provided with, respectively, one or more teeth which by self adjusting action of the pawl member are brought to engage aratchet wheel, which is associated with the engaging member of the ratchet wrench and rotatably carried in the wrench head, when the rocker is turned by hand to the position corresponding to the desired direction of operation. By this arrangement not only a very sturdy construction is obtained but, as already stated, the width of the ratchet wrench head may be highly reduced by having the ratchet wheel carried in the wrench head in such a manner that its teeth along most of the circumference are guided directly against the wrench head, due to the fact that the pawl member or members, respectively, take up very little space as viewed laterally.
The objects of the invention will be apparent when the following description is read with reference to the accompanying drawing in which:
Figure 1 shows the ratchet wrench in a perspective drawing with a part of the wrench head itself cut away. Figure 2 is a vertical, longitudinal cross-section, while Figures 3, 4 and 5 show the rocker and the pawl members set for clockwise, idling and anti-clockwise turning, respectively.
In the embodiment according to Figures 1-5, 1 denotes the wrench head and 2 the wrench handle together forming the main body of the wrench. The ratchet wheel 4, which is provided with an engaging member 3, is disposed in the head 1, the ratchet wheel rather snugly fitting the recess 5 formed in the wrench head and being carried in the same by means of the cover plates 6 and 7, detachably secured to the wrench head. Furthermore, there is in the recess 5 the rocker or carriage 11 attached to the pin 9 which is pivotable by means of the manipulator 8, the rocker in a freely rotatable manner carrying two pawl members 12 and 13 which are loosely retained in the rocker by means of a clip 14. The manipulator is retained in one or the other of its extreme positions (Figures 3 and 5) by means of a coil spring 15 in a.
2,978,081 Patented Apr. 4, 1961 manner known per se and will therefore act as a snap lock handle. As will be evident from Figure 3, the one pawl member 12 engages the ratchet wheel 4 when the manipulator 8 is turned to the left (Figure 3), and this will correspond to a clockwise rotating of the ratchet wheel 4. When the manipulator 8 is turned to the neutral position shown in Figure 4 both pawl members 12, 13 are out of engagement with the ratchet wheel 4 and when the manipulator 8 is turned to the right the pawl member 13 will engage the ratchet wheel 4 (Figure 5), this corresponding to an anticlockwise rotating of said ratchet wheel. When the member =12 as well as the member 16 engages the ratchet wheel 4 a self adjusting action takes place, as they turn in the rocker 11 in such a manner that all teeth on the pawl member operating for the time being will engage the ratchet wheel, for which reason a very strong force transmitting effect is obtained. For instance, when the pawl member 12 is in engagement with the ratchet wheel 4, which situation corresponds to a clockwise rotating of the ratchet wheel 4 when the wrench handle is turned to the left, the idling movement to the right of the wrench handle and thence the wrench head is permitted by a yielding rocking movement by the rocker 11, the position of which being controlled by the coil spring 15 received in the manipulator 8, which is deemed to be readily understood.
What is claimed is:
1. A ratchet wrench comprising a rocker, a pair of pawl members carried by said rocker, work engaging means including a rotatable ratchet wheel, each pawl having a plurality of teeth for engaging the teeth of said ratchet wheel, said rocker being pivotable between two positions in a first of which one of said pawls engages said ratchet wheel for clockwise rotation of said ratchet wheel, and in the second of which the other pawl engages said ratchet wheel for anti-clockwise rotation of said ratchet wheel, snap lock means for maintaining said rocker in a selected one of said positions, a handle for said rocker operable for selectively positioning said rocker, said pawls being mounted upon said rocker for pivotal movement relative to each other about axes parallel to the axis of said ratchet wheel for self-adjustment and full engagement of one of said pawls with said ratchet wheel when said rocker is in one of said extreme positions and full engagement of the other of said pawls with said ratchet wheel when said rocker is in the other of said extreme positions.
2. A ratchet wrench as defined in claim 1, in which a single wire retaining clip extends over the pawls and embraces the rocker for yieldably securing said pawls to said rocker.
References Cited in the file of this patent UNITED STATES PATENTS 349,007 Sinclair Sept. 14, 1886 1,209,320 Morneweck Dec. 19, 1916 1,680,515 Gormley Aug. 14, 1928 1,883,618 Dodge Oct. 18, 1932 2,542,241 Fors Feb. 20, 1951 2,711,111 Brame June 21, 1955 2,712,257 Fish July 5, 1955 OTHER REFERENCES Ser. No. 363,378, Thienes (A.P.C.), published May 4, 1943.