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(11) | EP 0 747 173 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
| published in accordance with Art. 158(3) EPC |
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| (54) | WRENCH |
| (57) A new type of usable solid wrench are provided for various hexagonal fastening pieces.
The solid wrench is convenient to use in narrow spaces without damaging corners of
fastening pieces and slipping. The solid wrench has two working positions each angled
relative to the other by an angle of θ ranged from 10 to 22 degrees in the same rotating
direction, the moving distance of the center of the two working positions along the
center line of the wrench's open end is less than or equal to one third of the hexagonal
workpiece's side length, all the bearing points are selected within the range of 0.55
- 0.85 of the corresponding hexagonal work piece's side length. Therefore, the new
type of solid wrench is easy to be manufactured and has lower cost for its simple
structure. |
[0002] Among the retrieved 27 patents related to solid wrenches at home and abroad from Jan. 1990 to June 1993, half of them are of multi-purpose type, some are improved types by adding some accessories, and the others are of rotating - slipping type. All these modifications are concentrated on convenience of usage, multi-purpose and high efficiency. But the results are not satisfied while using the patents when being evaluated with the comprehensive index of utility, good bearing strength, low cost and manufacturing method.
[0003] The object of the invention is directed to solve the above problems, and provides a type of solid wrench, whose main technical specifications are satisfied with the international standards, for more convenient to be inserted into working position, without damaging the corner of the fastening pieces and slipping, and for easy to use in narrow spaces less than 30 degrees. Said solid wrench has obvious advantages of manufacturing easily, lower cost, and high comprehensive evaluation index, so that it is easy to be put into production and application.
[0004] The technical features of the solid wrench are characterized in that a special geometrical shape is designed at its open end and two bearing edges for providing two working positions, each angled relative to the other by an angle of θ in the same rotating direction, in which θ ranges from 10 to 22 degrees; in that the intake of workpieces is made up of two inclined surfaces.
[0005] Fig. 1 shows said geometrical shape of working positions of the solid wrench in accordance with the preferred embodiment of the invention.
[0006] Fig. 2 shows said geometrical shape of working positions of the solid wrench in accordance with another preferred embodiment of the invention.
[0007] Referring to Figure 1, the solid wrench according to the preferred embodiment of the invention has two working positions, each angled relative to the other by an angle of θ in two rotating directions. The broken lines of the wrench's open end is formed as follows:
[0008] YY' is the central line of the wrench's open end. The original position of the regular hexagon ABCDEF which represents a hexagonal fastening piece is shown in Fig. 1, and its center is 0. Then, move the hexagon upward along the line YY' for a certain distance so that the center point moves from 0 to 0', in which 00' is not longer than one third of each side of the regular hexagon ABCDEF. Then rotate the regular hexagon in clockwise and counterclockwise directions by an angle of θ, respectively, (θ is selected within the range of 10-22 degrees) resulting two new hexagons abcdef and a'b'c'd'e'f'. In this case, ab and a'b' cross at G, de and d'e' cross at H, AB and bc at I, and DE intersects c'd' at J. The points G, H, I and J are the four bearing points. In order to have the bearing points fall within the range of 0.55 - 0.85 of the side length of the hexagon, 00' is given as one fifth of the side length and the angle θ as 15 degrees, as shown in Fig. 1. Formation of the broken line of the wrench's open end is illustrated in Figure 1. A relax angle α is provided to avoid damaging the corner of the workpiece as illustrated in Figure 1.
[0009] Referring to Figure 2, the solid wrench according to another preferred embodiment of the invention has two, working positions, each angled relative to the other by an angle θ in one rotating direction. The broken line of the wrench's open end is formed as follows:
[0010] The central line and original position of the regular hexagon at open end of the wrench are the same with those shown in Figure 1. Then move the hexagon upward along YY' for a given distance so that the center point moves from 0 to 0', in which 00' is not longer than one third of the regular hexagon ABCDEF's side length. Next, rotate the hexagon counterclockwise by an angle of θ (θ is selected within the range of 10-22 degrees) to form another hexagon abcdef. In this case, ab and AB cross at I; de and DE cross at H; and bc and AB at J; make a line through the point J perpendicular to YY' and extend the line which cross DE at K. Points I, H, J, K are the four bearing points. In order to have the bearing points fall within the range of 0.55 - 0.85 of the hexagon's side length, 00' is given as one eighth of the side length and the angle θ as 15 degrees, as shown in Fig. 2. Formation of the broken line at the open end of the wrench is illustrated in Fig. 2. A relax angle α is provided to avoid damaging the corner of the workpiece.
[0011] In Figs 1 and 2, an arc is drawn downward with 0 as the center and half of the length of the diagonal line of the regular hexagon as radius, so as to form the arc linking points B and D at the lower part of the wrench's open end, the arc is extended crossing the broken line of the wrench at B' and D'. All the acute corners of the open end of the wrench are designed as round ones to avoid stress concentration. Tolerance is in conformity with the National Standard, and the torque beared on the two special edges satisfies the C. D. series specifications of the National Standards. The angle between the central line of the wrench's open end and the handle of the wrench is 15 degrees.
[0012] With two working positions, each angled relative to the other by an angle of θ in the same rotating direction, the wrench can be rotated continuously without turning its sides when the rotated angle of the wrench's handle is larger than 30 degrees, or can be used by turning its sides in the narrow space where the rotated angle is less than 30 degrees.
[0013] The wrench according to the present invention provides advantages that a) it is easy to use because the inclined surfaces at the open end of the wrench can guide the wrench automatically when the wrench is inserted. b) it can enhance the performance of the wrench's bearing greater torque without slipping. Although the number of the corners on the open end of the wrench is more than traditional solid wrench, it is still easy to manufacture and popularize with only a little higher cost than traditional solid wrench. The wrench shown in Figure 2 is mainly designed for hexagonal fastening pieces with larger size, regardless of using in narrow spaces less than 30 degrees.
1. A new type of usable solid wrench comprising a head with its top end opened (open
end) and a handle.
Wherein the wrench has two working positions, each angled relative to the other by an angle of θ selected within the range of 10 - 22 degrees in the same rotating direction;
the moving distance of the center of the two working positions along the center line of the wrench's open end is less than or equal to one third of the corresponding hexagonal workpiece's side length; and
all the bearing points fall within the range of 0.55 - 0.85 of the corresponding hexagonal workpiece's side length.
Wherein the wrench has two working positions, each angled relative to the other by an angle of θ selected within the range of 10 - 22 degrees in the same rotating direction;
the moving distance of the center of the two working positions along the center line of the wrench's open end is less than or equal to one third of the corresponding hexagonal workpiece's side length; and
all the bearing points fall within the range of 0.55 - 0.85 of the corresponding hexagonal workpiece's side length.
2. The solid wrench according to claim 1, wherein:
relax angles are provided between bearing sides of the hexagonal workpiece and the wrench corresponding to bearing points, respectively, in which each angle is more than or equal to 3 degrees.
relax angles are provided between bearing sides of the hexagonal workpiece and the wrench corresponding to bearing points, respectively, in which each angle is more than or equal to 3 degrees.
3. The solid wrench according to claim 1 or claim 2 characterized in that:
the moving distance of the center of the regular hexagon along the center line of the wrench's open end is one fifth of the regular hexagon's side length; and in that said angle θ obtained by rotating the hexagon in clockwise or counterclockwise direction is 15 degrees.
the moving distance of the center of the regular hexagon along the center line of the wrench's open end is one fifth of the regular hexagon's side length; and in that said angle θ obtained by rotating the hexagon in clockwise or counterclockwise direction is 15 degrees.
4. The solid wrench according to claim 1 or 2 characterized in that:
the moving distance of the center of the regular hexagon along the center line of the wrench's open end is one eighth of the regular hexagon's side length; and said angle θ is 15 degrees.
the moving distance of the center of the regular hexagon along the center line of the wrench's open end is one eighth of the regular hexagon's side length; and said angle θ is 15 degrees.