Electronic torque wrench with sensing structure

An electronic torque wrench with sensing structure includes a tubular body, a working head and at least one sensing element. The working head includes a head section and a connection section secured in the front end of the tubular body. The head section is positioned at the front end of the tubular body. The sensing element is disposed on an outer circumference of the tubular body. Accordingly, the length of the connection section of the working head is greatly shortened and the internal structure of the tubular body is simplified to lower the material cost and manufacturing cost. In addition, the weight of the torque wrench is reduced and the sensing precision of the sensing element is enhanced, whereby a user can more easily hold the torque wrench and more smoothly use the torque wrench to enhance the whole benefit of the torque wrench.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic torque wrench, and more particularly to an electronic torque wrench with sensing structure.

2. Description of the Related Art

A torque wrench is used to tighten/untighten a threaded member. By means of detecting the torque value, the tightening extent of the threaded member can be controlled. Especially to a special or important apparatus, the structures of the components of the apparatus necessitate precise tightening extent. Therefore, the torque value of the torque wrench is preset to tighten the precise components in accordance with the necessary mechanical properties of the apparatus so as to meet the security regulation.

The conventional torque wrenches can be substantially classified into two types, that is, electronic torque wrench and mechanical torque wrench. Please refer toFIG. 1. A conventional electronic torque wrench10includes a tubular body11, a working head13and a strain gauge15. The working head13is mounted at the front end of the tubular body11. A flexible bar14is connected with the working head13and received in the tubular body11. The strain gauge15is mounted on the circumferential wall of the flexible bar14. In use of the torque wrench10, the strain gauge15can detect the deformation amount of the flexible bar14to measure the torque reached by the torque wrench10for a user to control the extent to which the torque wrench10tightens the threaded member.

However, in the conventional electronic torque wrench10, the strain gauge15is mounted on the flexible bar14of the working head13. Therefore, the body of the flexible bar14of the working head13must have a considerable length for arranging the strain gauge15. This not only leads to increase of the material cost and manufacturing cost of the torque wrench, but also leads to increase of weight of the torque wrench. As a result, the burden of a user in use of the torque wrench is increased.

Furthermore, the flexible bar14of the working head13is mounted in the tubular body11. Therefore, before the working head13is mounted on the tubular body11, it is necessary to first dispose the strain gauge15on the flexible bar14of the working head13and then the working head13can be assembled and mounted. This not only complicates the assembling process, but also leads to increase of the processing cost.

Moreover, the flexible bar14of the working head13is received in the tubular body11so that the diameter of the flexible bar14must be smaller than the diameter of the tubular body11. As a result, the body of the flexible bar14is quite slender and thus it is uneasy to assemble and mount the strain gauge15on the flexible bar14. This makes it difficult to assemble and mount the strain gauge15and leads to increase of the processing cost. In addition, the internal structure of the torque wrench10is more complicated. Accordingly, the conventional electronic torque wrench10has many shortcomings and is not optimal.

SUMMARY OF THE INVENTION

It is therefore a primary object of the present invention to provide an electronic torque wrench with sensing structure. The torque wrench includes at least one sensing element for detecting the torque value of the torque wrench. The sensing element can be more easily assembled and mounted on the torque wrench.

It is a further object of the present invention to provide an electronic torque wrench with sensing structure, the weight of the wrench is reduced.

It is still a further object of the present invention to provide an electronic torque wrench with sensing structure, the manufacturing cost of the wrench is lowered.

It is still a further object of the present invention to provide an electronic torque wrench with sensing structure, in which the measurement precision of the sensing element is enhanced.

To achieve the above and other objects, the electronic torque wrench with sensing structure of the present invention includes:

a tubular body having a passage at front end;

a working head including a head section and a connection section positioned at one end of the head section, the connection section of the working head being securely disposed in the passage of the tubular body; and

at least one sensing element disposed on an outer circumference of the tubular body.

Preferably, the tubular body further includes at least one indentation formed on outer circumference of the tubular body. The sensing element is disposed in the indentation.

Preferably, the connection section of the working head extends into the tubular body by such a depth that the connection section does not reach the position of the indentation.

Preferably, a force application section is formed at the rear end of the tubular body. The working head has a working part. A first length is defined between the working part and the sensing element. A second length is defined between the working part and the force application section. The ratio of the first length to the second length ranges from 1:1.4 to 1:3.

Preferably, the working head is formed with a hidden part received in the tubular body and an exposed part exposed to outer side of the tubular body. The ratio of the length of the hidden part to the length of the exposed part ranges from 1:2 to 1:5.

Still to achieve the above and other objects, the electronic torque wrench with sensing structure of the present invention alternatively includes:

a tubular body having a passage at front end;

a working assembly including a working head and a connection member, the rear end of the working head being separably assembled and connected with the front end of the connection member, the rear end of the connection member being securely disposed in the passage of the tubular body; and

at least one sensing element disposed on an outer circumference of the tubular body.

Preferably, the tubular body further includes at least one indentation formed on outer circumference of the tubular body. The sensing element is disposed in the indentation.

Preferably, the connection member extends into the tubular body by such a depth that the connection member does not reach the position of the indentation.

Preferably, the working assembly is formed with a hidden part received in the tubular body and an exposed part exposed to outer side of the tubular body. The ratio of the length of the hidden part to the length of the exposed part ranges from 1:2 to 1:5.

Preferably, a force application section is formed at the rear end of the tubular body. The working head has a working part. A first length is defined between the working part and the sensing element. A second length is defined between the working part and the force application section. The ratio of the first length to the second length ranges from 1:1.4 to 1:3.

According to the above arrangement, the sensing element of the torque wrench is mounted on the outer circumference of the tubular body so that it is unnecessary for the connection section of the working head/the body of the connection member of the working assembly to have a relatively long length. In this case, the length of the connection section/the connection member is greatly shortened so that the material cost and the manufacturing cost are lowered and the weight of the torque wrench is reduced. In this case, a user can more easily hold and use the torque wrench without affecting the operation of the torque wrench.

Furthermore, the sensing element of the torque wrench is mounted on the outer side of the torque wrench (on the outer circumference of the tubular body), not inside the torque wrench (the tubular body). Therefore, it is unnecessary to first dispose the sensing element on the working head/working assembly prior to assembling and mounting the working head/working assembly. Accordingly, the assembling process of the torque wrench is simplified. Also, the sensing element is disposed on the outer side of the torque wrench (on the outer circumference of the tubular body) so that the torque wrench can be more easily processed to lower the manufacturing cost of the torque wrench and simplify the internal structure of the torque wrench and enhance the whole benefit of the torque wrench.

In addition, a proper ratio relationship exists between the first length between the working part and the sensing element and the second length between the working part and the force application section so that the sensing element can more precisely detect and measure the torque change of the torque wrench. Accordingly, the torque of the torque wrench can be more precisely detected and measured.

Also, when the working assembly is disposed on the torque wrench, the working head of the working assembly is replaceable. In this case, a user can replace the working head of the torque wrench in accordance with different working sites. Therefore, the user can complete various wrenching and tightening operations without carrying different torque wrenches. Accordingly, the utility and diversity of the torque wrench are enhanced.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer toFIGS. 2 and 3. According to a first preferred embodiment, the electronic torque wrench20with sensing structure of the present invention includes a tubular body30, a working head40, a handle46and at least one sensing element50.

The tubular body30includes a passage32, at least one indentation34and a securing member36. The passage32axially extends through the tubular body30between a front end and a rear end of the tubular body30. An indentation34in the embodiment is formed on an outer circumference of the tubular body30and closer to the front end of the tubular body30.

The working head40includes a head section42. One end of the head section42is a connection section44. The head section42has a working part43where the head section42drives a work piece. The working part43is such as an insertion column for fitting with a socket to wrench a threaded member (bolt or nut). Alternatively, the working part43can be a polygonal fitting hole for fitting with a threaded member. The connection section44downward extends from the rear end of the head section42. In this embodiment, the head section42and the connection section44are a one-piece member, that is, the head section42and the connection section44are an integrated structure. The working head40is disposed at the front end of the tubular body30. The connection section44of the working head40is inserted from the front end of the passage32of the tubular body30into the passage32. The connection section44extends into the tubular body by such an inserting depth that the connection section44does not reach the position of the indentation34. That is, the indentation34is positioned behind the connection section44and the rear end of the connection section44does not exceed the front end of the indentation34. The securing member36of the tubular body30radially passes through the tubular body30and the connection section44of the working head40to assemble and connect the working head40and the tubular body30with each other. The head section42of the working head40is positioned at the front end of the tubular body30. When the working head40is mounted on the tubular body30, a part of the working head40is received in the tubular body30as a hidden part and another part of the working head40is exposed to outer side of the tubular body30as an exposed part. The ratio of the length L of the hidden part, that is, the inserting depth of the connection section), to the length S of the exposed part ranges from 1:2 to 1:5, and preferably from 1:2.5 to 1:4.5. In this embodiment, the ratio of the length L of the hidden part to the length S of the exposed part is 1:4.35.

The handle46is disposed at the rear end of the tubular body30. The handle46is formed with a force application section48. The force application section48is deemed as a section where the action force applied to the handle46is concentrated and serves as a force application point for operating the torque wrench20.

The sensing element50is a torque sensor such as a strain gauge. In this embodiment, one sensing element50is mounted for illustration purposes. The sensing element50is mounted in the indentation34of the tubular body30to detect the deformation amount of the tubular body30so as to measure the torque of the torque wrench20. The position of the sensing element50is closer to the front end of the tubular body30and farther from the rear end of the tubular body30. It should be noted that in this embodiment, the rear end of the handle46is positioned at the rear end of the tubular body30.

In the design of the present invention, a first length X is defined between the working part43of the head section42of the working head40and the center of the sensing element50. A second length Y is defined between the working part43of the head section42and the force application section48of the handle46. The ratio of the first length X to the second length Y ranges from 1:1.4 to 1:3, and preferably from 1:1.5 to 1:2.5. In this embodiment, the ratio of the first length X to the second length Y is 1:1.65.

The subject matter of the present invention is the improvement of the sensing structure of the torque wrench, while the other structures pertain to prior art and thus will not be further described hereinafter.

As shown inFIG. 3, the working head40of the present invention is inserted into the tubular body30by a short length so that the working head40is quite lightweight. This can greatly reduce the weight of the torque wrench20, whereby when a user operates the torque wrench, the user can more easily and smoothly hold and use the torque wrench20. When the torque wrench20wrenches a threaded member, the tubular body30is strained and the sensing element50can detect the strain of the tubular body30. In addition, a proper ratio relationship exists between the first length X between the working part43of the working head40and the sensing element50and the second length Y between the working part43of the working head40and the force application section48of the handle46so that the sensing element50can more precisely detect and measure the torque change of the working head40. Accordingly, the torque of the torque wrench20can be precisely detected and measured for a user to wrench and tighten the threaded member more precisely.

According to the above arrangement, the sensing element50is disposed in the indentation34of the outer circumference of the tubular body30to shorten the length of the rear end (the connection section44) of the working head40. In addition, a proper ratio relationship exists between the length L of the hidden part of the working head40and the length S of the exposed part of the working head40so as to minify the volume of the working head40and reduce the weight of the torque wrench20. In this case, a user can more lastingly use the torque wrench20without feeling tired. Moreover, the operation of the torque wrench20will not be affected so that the use of the torque wrench20is facilitated.

Moreover, in the present invention, the length of the connection section44of the working head40is shortened so that the working head40can be manufactured with less material. Accordingly, the cost for the material and the manufacturing can be lowered to enhance the economic benefit of the torque wrench20.

Furthermore, in the present invention, the sensing element50is disposed on the outer side of the torque wrench20(in the indentation34of the tubular body30), not inside the tubular body30of the torque wrench20. Therefore, the sensing element50can be more easily assembled and mounted to simplify the processing and assembling process of the relevant components of the torque wrench20and enhance the assembling efficiency. In addition, the internal structure of the torque wrench20can be simplified to lower the manufacturing cost of the torque wrench20. Accordingly, the whole benefit of the torque wrench20is enhanced.

In addition, a proper ratio relationship exists between the first length X between the working part43of the working head40and the sensing element50and the second length Y between the working part43of the working head40and the force application section48of the handle46. Therefore, when the torque wrench20wrenches a work piece, the sensing element50can more precisely detect and measure the torque change of the working head40. Accordingly, the currently reached torque of the torque wrench20can be precisely detected and measured for a user to wrench and tighten the threaded member more precisely.

Please now refer toFIG. 4, which shows a second embodiment of the torque wrench20′ of the present invention. The second embodiment of the torque wrench20′ of the present invention also includes a tubular body30, a handle46and a sensing element50. The same components are denoted with the same reference numerals and will not be redundantly described hereinafter. The second embodiment is different from the first embodiment in that the second embodiment includes a working assembly60including a working head62and a connection member67. The body of the working head62has a working part621. The rear end of the working head62has a connecting portion. In this embodiment, the connecting portion is a plug column63. The plug column63includes a locating assembly including a receiving socket64, an elastic member65and a locating member66. The receiving socket64is inward recessed from an outer circumference of the plug column63. In this embodiment, the elastic member65is a spring mounted in the receiving socket64. The locating member66is disposed in the receiving socket64. An outer end of the elastic member65serves to elastically push the locating member66to protrude from the outer circumference of the plug column63. The front end of the connection member67has a connection part. In this embodiment, the connection part is an insertion socket68. The insertion socket68is formed with a locating hole69disposed on an inner circumferential wall of the insertion socket68. The rear end of the connection member67is received in the passage32of the front end of the tubular body30and secured in the passage32by means of the securing member36. The connection member67is mounted in the tubular body30by such an inserting depth that the connection member67does not reach the position of the indentation34. The plug column63of the working head62is separably assembled in the insertion socket68of the connection member67. When the working head62is assembled with the connection member67, the plug column63of the working head62is plugged in the insertion socket68of the connection member67. At this time, the locating member66of the plug column63is elastically engaged and located in the locating hole69of the insertion socket68, whereby the working head62is affixed to the front end of the connection member67.

In this embodiment, the working assembly60also has a hidden part received in the tubular body30and an exposed part exposed to outer side of the tubular body30. The ratio of the length L of the hidden part to the length S of the exposed part ranges from 1:2 to 1:5, and preferably from 1:2.5 to 1:4.5. In this embodiment, the ratio of the length L of the hidden part to the length S of the exposed part is 1:4.35.

In this embodiment, a first length X is defined between the working part621of the working head62of the working assembly60and the sensing element50. A second length Y is defined between the working part621of the working head62of the working assembly60and the force application section48of the handle46. The ratio of the first length X to the second length Y ranges from 1:1.4 to 1:3, and preferably from 1:1.5 to 1:2.5. In this embodiment, the ratio of the first length X to the second length Y is 1:1.65.

According to the above arrangement, as shown inFIG. 5, the working head62of the working assembly60is replaceable. The working parts621of different forms of working heads62A,62B are applicable to different kinds or sizes of sockets or threaded members. For example, after a user uses the working head62A, the user can release and extract the plug column63of the working head62A out of the insertion socket68of the connection member67and then plug the plug column63of the working head62B into the insertion socket68of the connection member67and locate the plug column63therein. In this case, a user can use the torque wrench20′ in different working sites to complete different wrenching and tightening operations without carrying various torque wrenches. Accordingly, the utility and diversity of the torque wrench20′ are enhanced.

The second embodiment has the same effect as the first embodiment. The sensing element50is disposed in the indentation34of the outer circumference of the tubular body30, not inside the torque wrench. Therefore, the length of the connection member67can be greatly shortened to reduce the weight of the wrench and save the material. In addition, the sensing element50can be more easily assembled and mounted to simplify the internal structure of the torque wrench and the assembling process of the torque wrench and enhance the production efficiency of the wrench.

Furthermore, a proper ratio relationship exists between the first length between the working part621and the sensing element50and the second length between the working part621and the force application section48of the handle46so that the sensing element50can more precisely detect and measure the torque change of the torque wrench. Accordingly, the precision of the measurement of the torque of the torque wrench is enhanced.

In addition, in this embodiment, the working head62of the torque wrench is replaceable so that the utility and diversity of the torque wrench are enhanced.

Please refer toFIG. 6. It should be noted that in practice, a display and control device70can be mounted on the tubular body30of the torque wrench of the present invention. The display and control device70has a display screen72and several pushbuttons74. With the first embodiment of the torque wrench20taken as an example, a user can know the torque value of the torque wrench20from the display screen72and use the pushbuttons74to perform relevant operations, for example, setting the torque value. The sensing element can be snugly enclosed in the display and control device70.