Patent Grant
7878095
1. Field of the Invention
The present invention relates to an open end wrench, and more particularly to a reciprocatable open end wrench that can prevent the related components from being damaged.
2. Description of the Prior Art
Conventional open end wrenches are produced easily, but they can not be operated quickly.
To solve such a question, many improved open end wrenches have been developed, however they still have some disadvantages. For example, U.S. Pat. No. 4,158,975 discloses a unidirectional gripping open end wrench, and the radius of the arcuate surface of the D-shaped member is less than that of the concave arcuate surface of the jaw, hence as wrenching the fastening element, the D-shaped member contacts with the concave arcuate surface by one point contacting manner, and most of torque is forced on the projection on the side of the D-shaped member, thus causing the damage of the projection, and the open end wrench has lower strength. Besides, the upper and lower cover plates have to be disposed on the wrench to clamp and position the D-shaped member, thereby the open end wrench has to be produced in higher cost and tedious manufacturing process.
Likewise, the conventional open end wrenches disclose in the U.S. Pat. No. 3,695,125 and U.S. Pat. No. 4,158,975 have the same disadvantages exist.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.
The primary objective of the present invention is to provide a reciprocatable open end wrench that can enhance the strength and prevent the related components from being damaged.
To achieve the above-mentioned objectives, the reciprocatable open end wrench provided in accordance with the present invention comprises a handle and at least one driving head, the driving head being located at one end of the handle, wherein the driving head comprises:
a first jaw includes a first clamping surface;
a second jaw, the second jaw is disposed to correspond to the first jaw and includes a concave arcuate surface disposed on the inner side thereof;
a swing member includes a second clamping surface and a convex arcuate surface, between the first clamping surface and the second clamping surface is formed a working area, the radius of the convex arcuate surface is equal to that of the concave arcuate surface, and the swing member allows to slide relative to the concave arcuate surface;
a bottom surface, the bottom surface is located between the first jaw and the swing member, and the bottom surface includes a midpoint for dividing the width of the working area into two parts;
a stop portion, the stop portion is fixed between the second jaw and the swing member, as the open end wrench rotates a fastening element in one direction, the stop portion resists against the torque of the swing member; and
a returning device, one end of the returning device is biased against the swing member so that the swing member moves close to the stop portion at any time;
wherein between the concave arcuate surface and the convex arcuate surface is provided with an engagement structure which includes a slot member and a peripheral protrusion, both are disposed around the arcuate surface, so as to engage the swing member with the second jaw;
wherein the thicknesses of the swing member and the second jaw are equal;
wherein on the curve line of the convex arcuate surface of the swing member forms a center, and the height difference between the center of the convex arcuate surface and the midpoint of the bottom surface is H, the width of the working area is S, wherein the relation between S and H is
29% S<H<58% S.
The present invention will be clearer from the following description when viewed together with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiment in accordance with the present invention.
Referring to
The swing member 23 includes a second clamping surface 231 and a convex arcuate surface 232, between the second clamping surface 231 and the first clamping surface 211 is formed a working area, the radius of the convex arcuate surface 232 is equal to that of the concave arcuate surface 221, and the swing member 23 allows to slide relative to the concave arcuate surface 221, wherein the convex arcuate surface 232 includes a first peripheral protrusion 233 mounted therearound and engaging with the first slot 222 and having an arcuate hollow groove 234, and the radius of the first slot 222 is greater than that of the first peripheral protrusion 233. Besides, the through bore 223 of the second jaw 22 is in response to the hollow groove 234, and the retaining pin 224 is inserted into the hollow groove 234 through the through bore 223 so as to be limited to move in the hollow groove 234 and to prevent the swing member 23 from disengagement from the second jaw 22. The thickness of the swing member 23 is approximately identical to that of the second jaw 22.
The bottom surface 24 is located between the first jaw 21 and the swing member 23, and the bottom surface 24 includes a midpoint for dividing the width of the working area into two parts. The stop portion 25 is fixed between the second jaw 22 and the swing member 23, e.g., the stop portion 25 is attached on the upper periphery of the concave arcuate surface 221 so as to engage with the swing member 23.
The returning device 26 is installed between one end of the hollow groove 234 and the retaining pin 224, e.g., one end of the returning device 26 is biased against the swing member 23 so that the convex arcuate surface 232 of the swing member 23 moves close to the stop portion 25.
With reference to
29% S<H<58% S.
When the height difference is within the above-mentioned range, the user can rotate a fastening element in the clockwise direction; on the contrary, as the user rotates the open end wrench in the counter-clockwise direction, the open end wrench rotates idly to return back to its original position so as not to drive the fastening element.
Referring to
With reference to
Referring to
In the third embodiment of the present invention, the through bore and the retaining pin can also be secured on the swing member, and the hollow groove can be disposed on the second peripheral protrusion of the second jaw, thereby preventing the swing member and the second jaw from disengagement.
As shown in
Referring to
As illustrated in
It can be clearly seen from the preceding accounts on the features of the present invention that the reciprocatable open end wrench of the present invention has the following advantages:
1. The open end wrench includes the slot member and the peripheral protrusion so as to engage with each other, thus preventing the swing member from swing and simplifying the necessary components, such as the conventional cover plates in the driving head. Besides, it has higher mechanical strength than the conventional cover plates.
2. Because the radiuses of the concave and convex arcuate surfaces are the same, the swing member can matingly engage with the second jaw, such that as rotating the fastening member, the convex arcuate surface of the swing member passes the force to the second jaw to obtain higher structural strength and to prevent the retaining pin or the swing member from being damaged due to the force is concentrated on the retaining pin.
3. By arranging the stop portion, the torque on the swing member forced by the fastening element can be resisted to stop the swing member from disengagement and the torque from concentration on the retaining pin.
4. Because the thicknesses of the swing member and the second jaw are equal, obtaining better strength.
5. The engagement structure can be designed to a dovetail slot for matching with a third peripheral protrusion, therefore the swing member can more tightly engage with the second jaw, avoiding the power waste due to the swinging of the swing member.
While we have shown and described various embodiments in accordance with the present invention, it is clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.
| Number | Name | Date | Kind |
|---|---|---|---|
| 1320668 | Askman | Nov 1919 | A |
| 2846912 | Day | Aug 1958 | A |
| 3695125 | Glass et al. | Oct 1972 | A |
| 4158975 | DeSousa | Jun 1979 | A |
| 5287777 | Kolodziej | Feb 1994 | A |
| Number | Date | Country | |
|---|---|---|---|
| 20100071516 A1 | Mar 2010 | US |
