GB2347374A

GB2347374A - An open wrench

Info

Publication number: GB2347374A
Application number: GB9901804A
Authority: GB
Inventors: Chih-Ching Hsieh
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-01-27
Filing date: 1999-01-27
Publication date: 2000-09-06
Also published as: GB9901804D0

Abstract

An open end wrench comprises two jaws, a nest connected between the jaws, a flat raised portion 11 and a longitudinal series of teeth 12 inside the jaws for grasping and turning polygonal head bolts or nuts. The length of the flat raised portion is equal to the distance from the midpoint of a first tooth 125 to the midpoint of a last tooth 121 in the longitudinal series of teeth. The total length (B, fig 18) of the longitudinal series of teeth is equal to 0.67 of the width (A, fig 18) of the mouth, and the distance (C, fig 18) from the remote end of the longitudinal series of teeth to the nest is 0.91 the width of the mouth. There is an odd number of teeth, and the first and second teeth, 125, 124, when counting from an end adjacent the nest, are smoothly curved. The third and fourth teeth 124, 123, when counting from an end adjacent the nest are pointed.

Description

OPEN END WRENCH PRACTICAL FOR TURNING NORMAL AND WON-OUT BOLTS AND NUTS OF DIFFERENT SPECIFICATIONS This invention relates to an open end wrench practical for turning normal and won-out bolts and nuts of different specifications.

The present invention relates to open end wrenches and more particularly to an improved structure of open end wrench which is practial for grasping and turning normal bolts and nuts of different specifications as well as won-out bolts and nuts of different specifications.

An open end wrench is handy tool intensively used for grasping and turning bolts and nuts. A variety of open end wrenches have been disclosed having teeth, raised portions or rough grasping faces at the jaws for grasping and turning normal bolts and nuts as well as won-out bolts and nuts. ExemPlars of conventional open end wrenches are shown in Figures from 1 to 13. The open end wrench shown in Figures 1, 2, adn 3 has two flat raised portions at the jaws. This structure of open end wrench is functional for turning normal bolts and nuts as well as slightly won-out bolts and nuts.

However, it can not positively grasp and turn excessively won-out bolts and nuts. Figures 4, 5,7,8, 9,10 and 11 show other different designs. These designs can grasp and turn bolts an nuts of different sizes. However, these designs can not positively grasp and turn excessively won-out bolts and nuts. Figure 6 shows another design of open end wrench which is similar to the open end wrench shown in Figures 1 to 3.

Figure 12 shows an open end wrench having rough faces at the jaws. Figure 13 shows an open end wrench having teeth at the jars. The open end wrenches shown in Figures 12 and 13 can positively grasp and turn normal bolts and nuts, however they tend to slip when turn an excessively won-out bolt or nut.

It is one object of the present invention to provide an open end wrench which is practical for grasping and turning hexagon head bolts and hexagon nuts as well as square head bolts and square nuts. It is another object of the present invention to provide an open end wrench which is practical for grasping and turning normal bolts and nuts of different specifications as well as worn-out bolts and nuts of different specifications. According to the present invention, the open end wrench comprises a mouth defined between two jaws and nest thereof, a flat raised portion and a longitudinal series of teeth respectively raised from the two jaws inside the mouth, the longitudinal series of teeth including an odd number of teeth, the length of the flat raised portion being equal to the distance between the mid point of the first tooth of the longitudinal series of teeth and the midpoint of the last tooth thereof, the total length of the longitudinal series of teeth being equal to 0. 67 of the width of the mouth, the distance from the remote end of the longitudinal series of teeth to the nest being 0. 91 of the vidth of the mouth, the first tooth of the longitudinal series of teeth and the second tooth thereof having a respective smoothly curved peak for grasping normal square head bolts and square nuts and normal hexagon head bolts and hexagon nuts, the third tooth and the fourth tooth of the longitudinal series of teeth being pointe. d teeth, the distance between the aid point of the flat raised portion and the third tooth of the longitudinal series of teeth being equal to the width of the mouth, the fifth tooth of the longitudinal series of teeth being for turning hexagon head bolts, hexagon nuts, square head bots and square nuts in the reversed direction.

An embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which Figure 1 shows a combination wrench according to the prior art ; Figure 2 is an enlarged view of the open end of the combination wrench shown in Figure 1 ; Figure 3 shows an application example of the open end of the combination wrench shown in Figure 1 ; Figure 4 shows another structure of open end wrench according to the prior art ; Figure 5 shows still another structure of open end wrench according to the prior art ; Figure 6 shows still another structure of 15 open end wrench according to the prior art ; Figure 7 shows still another structure of open end wrench according to the prior art ; Figure 8 shows still another structure of open end wrench according to the prior art ; 20 Figure 9 shows still another structure of open end wrench designed for turning bolts and nuts of different specifications according to the prior art ; Figure 10 shows still another structure of open end wrench according to the prior art ; Figure 11 shows still another structure of open end wrench designed for turning bolts and nuts of different specifications according to the prior art ; Figure 12 shows still another structure of open end wrench according to the prior art where the jaws have a respective rough grasping face at an inner side ; Figure 13 shows still another structure of open end wrench according to the prior art where the jaws have a respective longitudinal row of teeth at an inner side for grasping ; Figure 14 is a perspective view of an open end wrench according to the present invention ; Figure 15 shows the open end wrench grasped on a normal hexagon head bolt according to the present invention ; Figure 16 shows the open end wrench grasped on a won-out bolt according to the present invention ; Figure 17 shows the open end wrench grasped on a normal square head bolt according to the present invention ; Figure 18 shows the relationship between the open end wrench and the hexagon head bolt to be turned ; Figure 19 is a schematic drawing explaining the design of the open end of the open end wrench according to the present invention ; Figure 20 is a schematic drawing explaining the design of the present invention ; Figure 21 is a schematic drawing analyzing the specification of a normal hexagon head bolt according to the present invention ; and Figure 22 is a schematic drawing explaining the maximum torque angle and the minimum torque angle according to the present invention ; Referring to the various drawings attached herewith, a detailed description of the structural features of an open end wrench of the present invention is as follows :- An open end of an open end wrench according to the present invention is similar to regular open end wrenches, comprising two jaws, a nest connected between the jaws, and a mouth defined within the jaws and the nest and adapted for grasping and turning bolts, nuts, etc.

Referring to Figures from 14 to 16, the open end comprises a flat raised portion 11 and a longitudinal series of teeth 12 respectively raised from the jaws inside the mouth. The length of the flat raised portion 11 is equal to the distance between the aid point of the first tooth 125 of the longitudinal series of teeth and the midpoint of the last tooth 121 thereof. The total length B of the longitudinal series of teeth 12 is equal to 0. 67 of the width A of the oouth. The distance C from the remote end of the longitudinal series of teeth 12 to the nest is 0. 91 of the width A of the soute. The number of the longitudinal series of teeth 12 is an odd number. When counting from the end adjacent to the nest toward the end remote from the nest, the first tooth 125 and second tooth 124 of the longitudinal series of teeth 12 have a respective smoothly curved peak for grasping normal square head bolts and square nuts as well as normal hexagon head bolts and hexagon nuts. The third tooth 123 and the fourth tooth 122 are pointed teeth. The distance between the mid point of the flat raised portion 11 and the third tooth 123 of the longitudinal series of teeth 12 is equal to the width of the zouth. Therefore, the third tooth 123 and the fourth tooth 122 are practical for grasping and turning won-out bolts and nuts. The fifth tooth 121 is practical for grasping and turning normal hexagon head bolts and hexagon nuts as well as normal square head bolts and square nuts in the reversed direction. Figure 15 shows the open end wrench grasped on a hexagon head bolt 3. Figure 16 shows the open end wrench grasped on a won-out bolt. Figure 17 shows the open end wrench grasped on a square head bolt 4.

Referring to Figures from 18 to 20 when turning a normal hexagon head bolt 3, the maximum torque angle is 6 1, the minimum torque angle is 0 2. As known that the width of the oouth is S, the maximum turnable polygonal head bolt size is S1, the minimum turnable polygonal head bolt size is S2. Further, the distance between two diagonal angles of the polygonal head 3 is h. From the data provided it is obtained : S=h * COS30 ........ normal polygonal head bolt Y=h-x/2 x=h * COS60 =1/2h C1=x+y=h COS60 +h-h COS60 /2=h/2+h/2 COS60 =3/4h d1=75% round off dl=2rl=2 (0. 125h+0. 875S) A=dl COSP W1=dl sinα Referring to Figures 21 and 22, in consideration with the maximum torque angle is 0 1 and the minimum torque angle is 8 2 it is obtained : S=h COS 2 S2=S1-1

f=e Sin The design of the invention is obtained subject to the aforesaid equotions.

Claims

CLAIM :-

1. An open end wrench comprising two jaws, a nest connected between said jaws, and a mouth defined within said jaws and said nest, a flat raised portion and a longitudinal series of teeth respectively raised froe said jaws inside said routh for grasping and turning polygonal head bolts and nuts, wherein the length of said flat raised portion is equal to the distance between the mid point of the first tooth of said longitudinal series of teeth and the midpoint of the last tooth thereof, the total length of said longitudinal series of teeth being equal to 0. 67 of the width of said nouth, the distance from the remote end of said longitudinal series of teeth to said nest being 0. 91 of the width of said nouth, the nunber of said longitudinal series of teeth being an odd nuaber, the first tooth of said longitudinal series of teeth and the second tooth thereof, when counting from the end adjacent to said nest toward the end renote fron said nest, having a respective smoothly curved peak for grasping normal square head bolts and square nuts and normal hexagon head bolts and hexagon nuts, the third tooth and th fourth tooth of said longitudinal series of teeth being pointed teeth, the distance between the nid point of said flat raised portion and the third tooth of said longitudinal series of teeth being equal to the width of said oouth, the fifth tooth of said longitudinal series of teeth being for turning hexagon head bolts, hexagon nuts, square head bolts and square nuts in the reversed direction.

2. An open end wrench substantially as hereinbefore described with reference to, and as illustrated in figures 14 to 22.