Torque output device for ratchet wrench

A torque output device includes a body with an opening in the top. A top toothed part is located beneath the opening and includes a bore located corresponding to the opening. The top toothed part includes multiple top teeth. A drive shaft secured in the body and includes a central hole in which a rod is located. A driving portion is formed to the lower end of the drive shaft. The drive shaft and the top toothed part are freely rotated relative to each other. A bottom toothed part is mounted to the drive shaft and freely moves up and down relative to the drive shaft. A resilient member is mounted to the drive shaft and biases the bottom toothed part. A pressure collar is threadedly connected to the lower end of the body to set the torque between the engagement of the top and bottom teeth.

BACKGROUND OF THE INVENTION

a) Field of the Invention

The present invention relates to a torque output device for a ratchet wrench, and more particularly, to a torque output device that precisely sets the output torque.

b) Description of the Prior Art

The conventional way to fasten objects is to use a wrench to tighten a bolt or the like. In order to properly apply a specific torque to the bolt, the users have to carefully to feel the tightness when rotating the bolt. However, this conventional way is not a precise method to apply the desired torque to the bolt, and the bolt may be overly rotated and broken, or the object is damaged due to the improper torque applied. A torque wrench is used where to set the desired torque to be applied to the bolt so that it can be matched to the specifications for a particular application.

The known torque wrenches includes a compression spring, and when the set output is reached, there is a mechanism to be disengaged from the spring so as to create a sound. The users then are acknowledged that the desired torque is applied to the bolt. Nevertheless, there always a time lap when the users hear the sound and stop operating the torque wrench. In other words, the bolt will be rotated by an exceeded torque because of the time lap. Besides, the conventional torque wrenches cannot be cooperated with pneumatic or electric tools.

The present invention intends to provide a torque output device that eliminates shortcomings mentioned above.

SUMMARY OF THE INVENTION

The present invention relates to a torque output device and comprises a body having a U-shaped cross section. An opening is formed centrally in the top thereof. A washer is connected to the lower end of the body. A top toothed part is fixed to the body and located beneath the opening. The top toothed part includes a bore defined centrally therein. The top toothed part includes multiple top teeth extending from the underside thereof. The bore is located corresponding to the opening. Each top tooth of the top toothed part includes an angle between two tooth surfaces thereof, and the angle is 10 to 90 degrees. Each top tooth of the top toothed part includes a rounded corner at the left corner of the top land thereof. A drive shaft includes a central hole defined centrally in the top thereof. A rod is located in the central hole. Multiple first grooves are formed axially along the outer surface of the upper section of the drive shaft. A driving portion is formed to the lower end of the drive shaft. A bolt extends through bore of the top toothed part and is connected to the central hole of the drive shaft. The bolt contacts the rod in the central hole so that the drive shaft and the top toothed part are freely rotated relative to each other. A bottom toothed part is mounted to the drive shaft and includes multiple bottom teeth which are engaged with the top teeth of the top toothed part. Each bottom tooth of the bottom toothed part includes a rounded corner at the right corner of the top land thereof. Multiple second grooves are formed axially along the inner surface of the bottom toothed part and located corresponding to the first grooves of the drive shaft. A stop plate is connected to the lower end of the second grooves. Multiple rollers are rotatably located between the first and second grooves so that the bottom toothed part is movable axially relative to the drive shaft. A resilient member is mounted to the drive shaft. The resilient member is biased between the bottom toothed part and the washer. A pressure collar is threadedly connected to the lower end of the body.

Preferably, a top driving portion is formed to the top of the body.

Preferably, the top driving portion is integrally formed with the body.

Preferably, multiple balls are located between the washer and the pressure collar.

Preferably, the body includes a grip formed to an outside thereof.

Preferably, a first seal is located between a top of the top toothed part and the opening of the body. A second seal is located between the pressure collar and the drive shaft. A third seal is located between the pressure collar and the body. The body includes lubricant received therein.

Preferably, each top tooth of the top toothed part includes a rounded corner at the right corner of the top land thereof. Each bottom tooth of the bottom toothed part includes a rounded corner at the left corner of the top land thereof.

Preferably, a cushion plate is located at the top of the second grooves of the bottom toothed part.

Another embodiment of the torque output device of the present invention comprises a body having a U-shaped cross section. An engaging hole is formed in the top thereof so as to be connected with a wrench. A washer is connected to a lower end of the body. Atop toothed part is fixed to the body and located beneath the engaging hole. The top toothed part includes a bore defined centrally therein. Multiple top teeth extend from the underside of the top toothed part. The bore is located corresponding to the engaging hole. Each top tooth of the top toothed part has an angle between two tooth surfaces thereof. The angle is 10 to 90 degrees. Each top tooth of the top toothed part includes a rounded corner at the left corner of the top land thereof. A drive shaft includes a central hole defined centrally in the top thereof. A rod is located in the central hole. Multiple first grooves are formed axially along the outer surface of the upper section of the drive shaft. A driving portion is formed to the lower end of the drive shaft. A bolt extends through bore of the top toothed part and is connected to the central hole of the drive shaft. The bolt contacts the rod in the central hole so that the drive shaft and the top toothed part are freely rotated relative to each other. A bottom toothed part is mounted to the drive shaft and includes multiple bottom teeth which are engaged with the top teeth of the top toothed part. Each bottom tooth of the bottom toothed part includes a rounded corner at the right corner of the top land thereof. Multiple second grooves are formed axially along the inner surface of the bottom toothed part and located corresponding to the first grooves of the drive shaft. A stop plate is connected to the lower end of the second grooves. Multiple rollers are rotatably located between the first and second grooves so that the bottom toothed part is movable axially relative to the drive shaft. A resilient member is mounted to the drive shaft, and the resilient member is biased between the bottom toothed part and the washer. A pressure collar is threadedly connected to the lower end of the body.

Preferably, multiple balls are located between the washer and the pressure collar.

Preferably, a first seal is located between the top of the top toothed part and the engaging hole of the body. A second seal is located between the pressure collar and the drive shaft. A third seal is located between the pressure collar and the body. The body includes lubricant received therein.

Preferably, each top tooth of the top toothed part includes a rounded corner at the right corner of the top land thereof. Each bottom tooth of the bottom toothed part includes a rounded corner at the left corner of the top land thereof.

Preferably, a cushion plate is located at a top of the second grooves of the bottom toothed part.

The present invention also provides yet another embodiment of the torque output device which comprises a body having a U-shaped cross section and an engaging hole is formed centrally in the top thereof. Multiple threads are formed on the outer surface of the lower end of the body. A mark ring is mounted to the upper portion of the body and secured by a fastening member. A top toothed part is fixed to the body and located beneath the engaging hole. The top toothed part includes a bore defined centrally therein. Multiple top teeth extend from the underside of the top toothed part. The bore is located corresponding to the engaging hole. Each top tooth of the top toothed part has an angle between two tooth surfaces thereof. The angle is 10 to 90 degrees. Each top tooth of the top toothed part includes a rounded corner at the left corner of the top land thereof. A drive shaft includes a central hole defined centrally in the top thereof. A rod is located in the central hole. Multiple first grooves are formed axially along the outer surface of the upper section of the drive shaft. A driving portion is formed to the lower end of the drive shaft. A clip is mounted to the outside of the driving portion. A bolt extends through the bore of the top toothed part and is connected to the central hole of the drive shaft. The bolt contacts the rod in the central hole so that the drive shaft and the top toothed part are freely rotated relative to each other. A bottom toothed part is mounted to the drive shaft and includes multiple bottom teeth which are engaged with the top teeth of the top toothed part. Each bottom tooth of the bottom toothed part includes a rounded corner at the right corner of the top land thereof. Multiple second grooves are formed axially along the inner surface of the bottom toothed part and located corresponding to the first grooves of the drive shaft. A stop plate is connected to the lower end of the second grooves. Multiple rollers are rotatably located between the first and second grooves so that the bottom toothed part is movable axially relative to the drive shaft. A first resilient member is mounted to the drive shaft. The top end of the first resilient member contacts the bottom toothed part. A pressure collar is mounted to the drive shaft and contacting the lower end of the first resilient member. A torque adjustment member has multiple threads formed in the inner periphery thereof. The torque adjustment member is threadedly connected to the body from the lower end of the body. The inner end of the lower end of the torque adjustment member contacts the underside of the pressure collar. The torque adjustment member includes a radial hole defined through the wall thereof. When the torque adjustment member is rotated relative to the body, the first resilient member is compressed by the pressure collar. A securing unit is connected to the radial hole of the torque adjustment member so as to secure the torque adjustment member to the body.

Preferably, the first resilient member is located within a second resilient member, wherein the second resilient member is biased between the bottom toothed part and the pressure collar.

Preferably, a first seal is located between the top toothed part and the engaging hole of the body. A second seal is located between the pressure collar and the drive shaft. A third seal is located between the pressure collar and the body. The body includes lubricant received therein.

Preferably, the securing unit includes a tube which is welded to the radial hole of the torque adjustment member. A copper sleeve is located in the tube and has multiple threads which are threadedly connected to the threads of the body. A screw is threadedly connected to the tube and contacts the copper sleeve so as to secure the torque adjustment member to the body.

Preferably, a washer is located on the inner end of the lower end of the torque adjustment member. A room is formed between the pressure collar and the washer. The multiple balls are located in the room between the pressure collar and the washer.

Preferably, each top tooth of the top toothed part includes a rounded corner at the right corner of the top land thereof. Each bottom tooth of the bottom toothed part includes a rounded corner at the left corner of the top land thereof.

Preferably, a cushion plate is located at the top of the second grooves of the bottom toothed part.

The present invention provides a torque output device cooperated with a wrench and is cable to precisely output a torque. When the desired torque reaches, the bottom toothed part is disengaged from the top toothed part and moved freely relative to the drive shaft with almost zero friction.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring toFIGS.1and2A, the torque output device100of the present invention comprises a body110, a mark ring120, a top toothed part130, a drive shaft140, a bottom toothed part150, multiple rollers160, a first resilient member170, a pressure collar180, a torque adjustment member190and a securing unit200.

The body110has a U-shaped cross section and an engaging hole112is formed centrally in the top thereof so as to be connected with a wrench, a pneumatic tool or an electric tool. Multiple threads114are formed on the outer surface of the lower end of the body110. The mark ring120is mounted to the upper portion of the body110and secured by a fastening member122.

As shown inFIGS.2A and3, the top toothed part130is fixed to the body110and located beneath the engaging hole112. The top toothed part130includes a bore132defined centrally therein. Multiple top teeth134extend from the underside of the top toothed part130. The bore132is located corresponding to the engaging hole112. Each top tooth134of the top toothed part130has an angle “A” between two tooth surfaces thereof. The angle “A” is 10 to 90 degrees.

As shown inFIGS.2A and4, a drive shaft140includes a central hole141defined centrally in the top thereof. A rod143is located in the central hole141. Multiple first grooves142are formed axially along the outer surface of the upper section of the drive shaft140. A driving portion144is formed to the lower end of the drive shaft140so as to be connected to an object (not shown). A bolt145extends through the bore132of the top toothed part130and is connected to the central hole141of the drive shaft140. The lower end of the bolt145contacts the rod143in the central hole141so that the bolt145cannot be further lowered in the central hole141, such that the head of the bolt145does not connect the top toothed part130to the drive shaft140. In other words, there is a small gap formed between the head of the bolt145and the top toothed part130. Therefore, the drive shaft140and the top toothed part130are freely rotated relative to each other. The driving portion144as shown inFIG.2Bcan be a rectangular protrusion or a hexagonal recess so as to be connected to a socket or a screwdriver bit. A clip146is mounted to the outside of the driving portion144so as to prevent the torque adjustment member190from dropping.

As shown inFIG.5, the bottom toothed part150is mounted to the drive shaft140and includes multiple bottom teeth152which are engaged with the top teeth134of the top toothed part130. Each top tooth134of the top toothed part130includes a rounded corner135at the left corner of the top land thereof. Each bottom tooth152of the bottom toothed part150includes a rounded corner153at the right corner of the top land thereof. Therefore, when a desired torque reaches, the bottom toothed part150can be successfully disengaged from the top toothed part130. It is noted that the rounded corners135,153can also be formed in each corner of the top land of each of the top tooth134and each bottom tooth152.

Multiple second grooves154are formed axially along the inner surface of the bottom toothed part150and located corresponding to the first grooves142of the drive shaft140. Multiple rollers160are rotatably located between the first and second grooves142,154so that the bottom toothed part150is movable axially relative to the drive shaft140. That is to say, the bottom toothed part150is movable axially relative to the drive shaft140with almost zero friction. A stop plate156is connected to the lower end of the second grooves154to restrict the rollers156from dropping. A cushion plate158is located at the top of the second grooves154of the bottom toothed part150so as to reduce vibration or impact when the bottom toothed part150is separated from the top toothed part130.

The first resilient member170is mounted to the drive shaft14. The top end of the first resilient member170contacts the bottom toothed part150. A pressure collar180is mounted to the drive shaft140and contacting the lower end of the first resilient member170. In another embodiment, the torque adjustment device100includes a second resilient member172. The first resilient member170is located within the second resilient member172, and the second resilient member172is biased between the bottom toothed part150and the pressure collar180.

The torque adjustment member190has multiple threads192formed in the inner periphery thereof. The torque adjustment member190is threadedly connected to the body110from the lower end of the body110. The inner end of the lower end of the torque adjustment member190contacts the underside of the pressure collar180. When the torque adjustment member190is rotated relative to the body110, the first and second resilient members170,172are compressed by the pressure collar180. The torque adjustment member190includes a radial hole196defined through the wall thereof. A securing unit200is connected to the radial hole196of the torque adjustment member190so as to secure the torque adjustment member190to the body110.

Specifically, when the torque adjustment member190is rotated relative to the body110, the first and second resilient members170,172are compressed by the pressure collar180so as to provide a force (frictional force) to engage the bottom toothed part130with the top toothed part150. When the users use the present invention to apply a torque to an object that is connected to the driving portion144, the frictional force between the top and bottom toothed parts130,150rotates both of the top and bottom toothed parts130,150. The drive shaft140is rotated by the bottom toothed part150because the rollers160are located in the first and second grooves142,154. The shaft140is therefore rotated to transfer a torque to the object engaged with the driving portion144. When the users apply the torque that is larger than the frictional force between the top and bottom toothed parts130,150, the top and bottom toothed parts130,150are separated from each other. The bottom toothed part150moves up and down relative to the drive shaft140because of the rollers160in the first and second grooves142,154, and cannot drive the drive shaft140to rotate. Thanks to the rollers160located between the first and second grooves142,154, the bottom toothed part150moves with almost zero frictional force relative to the drive shaft140. Accordingly, the torque that separates the top toothed part130from the bottom toothed part150is the desired torque that is equal to the frictional force between the top and bottom toothed parts130,150. The force required to achieve the desired torque equals to the force that the first and second resilient members170,172applied to the bottom toothed part150.

Assume the frictional force between the first and second resilient members170,172is fixed, then the larger the angle “A” of each top tooth134of the top toothed part130, the smaller the frictional force between the top and bottom toothed parts130,150. In other words, a smaller output torque can be reached. On the contrary, the smaller the angle “A” of each top tooth134of the top toothed part130, the larger the frictional force between the top and bottom toothed parts130,150. In other words, the larger output torque can be reached. However, if the angle “A” is too large, the frictional force between the top and bottom toothed parts130,150will be too small, or if the angle “A” is too small, the frictional force between the top and bottom toothed parts130,150will be too large, both situations do not meet practical needs. Preferably, the angle “A” is 10 to 90 degrees.

Preferably, a first seal102is located between the top toothed part130and the engaging hole112of the body110. A second seal104is located between the pressure collar180and the drive shaft140. A third seal106is located between the pressure collar180and the body110. The body110includes lubricant received therein. As shown inFIG.2A, the lubricant provides features of lubrication and heat dissipation.

A washer107is located on the inner end of the lower end of the torque adjustment member190. A room is formed between the pressure collar180and the washer107. The multiple balls108are located in the room between the pressure collar180and the washer107. As shown inFIG.2A, the balls108reduce friction between the pressure collar180and the torque adjustment member190.

As shown inFIG.6, the securing unit200includes a tube202which is welded to the radial hole196of the torque adjustment member190. A copper sleeve204is located in the tube202and has multiple threads205which are threadedly connected to the threads114of the body110. A screw206is threadedly connected to the tube202and contacts the copper sleeve204so as to secure the torque adjustment member190to the body110.

When the users rotate the torque adjustment member190to push the pressure collar180to compress the first and second resilient members170,172to set the desired output torque, the top edge of the torque adjustment member190is adjusted to be aligned with the marks or digits on the mark ring120. When the desired torque value is set, the screw206in the tube202is then tightened to engage the copper sleeve204with the threads114of the body110to position the torque adjustment member190relative to the body110to complete the desired torque setting.

As shown inFIG.7, a second embodiment of the torque output device300is disclosed and comprises a body310, a top toothed part320, a drive shaft330, a bottom toothed part340, multiple rollers350and a pressure collar370.

The body310has a U-shaped cross section. An opening312is formed centrally in the top thereof. A washer314is connected to the lower end of the body310. The top toothed part320is fixed to the body310and located beneath the opening312. The top toothed part320includes a bore322defined centrally therein. The top toothed part320includes multiple top teeth extending from the underside thereof. The bore322is located corresponding to the opening312. Each top tooth of the top toothed part320includes an angle “A” between two tooth surfaces thereof, and the angle “A” is 10 to 90 degrees.

The drive shaft330includes a central hole331defined centrally in the top thereof. A rod333is located in the central hole331. Multiple first grooves332are formed axially along the outer surface of the upper section of the drive shaft330. A driving portion334is formed to the lower end of the drive shaft330. A bolt335extends through bore322of the top toothed part320and is connected to the central hole331of the drive shaft330. The bolt335contacts the rod333in the central hole331so that the drive shaft330and the top toothed part320are freely rotated relative to each other.

The bottom toothed part340is mounted to the drive shaft330and includes multiple bottom teeth which are engaged with the top teeth of the top toothed part320. Each bottom tooth of the bottom toothed part340includes a rounded corner at the right corner of the top land thereof so that when the desired torque is reached, the bottom toothed part340is disengaged from the top toothed part320. Alternatively, each bottom tooth of the bottom toothed part340includes a rounded corner at both corners of the top land thereof. Multiple second grooves344are formed axially along the inner surface of the bottom toothed part340and located corresponding to the first grooves332of the drive shaft330. A stop plate346is connected to the lower end of the second grooves344. A cushion plate348is located at the top of the second grooves344of the bottom toothed part340. Multiple rollers350are rotatably located between the first and second grooves332,344so that the bottom toothed part340is movable axially relative to the drive shaft330.

The resilient member360is mounted to the drive shaft330. The resilient member360is biased between the bottom toothed part340and the washer314. A pressure collar370is threadedly connected to the lower end of the body310. Multiple balls372are located between the washer314and the pressure collar370so as to reduce friction between the pressure collar370and the washer314.

Specifically, the pressure collar370contacts the washer314so as to compress the resilient member360to provide a force (frictional force) to engage the top and bottom toothed parts320,340. When the users use the present invention to apply a torque to an object, the frictional force between the top and bottom toothed parts320,340rotates both of the top and bottom toothed parts320,340. The shaft140is therefore rotated and transfers the torque to the object connected to the driving portion334. When the users apply the torque that is larger than the frictional force between the top and bottom toothed parts320,340, the top and bottom toothed parts320,340are separated from each other, so that the drive shaft330is not driven and rotated. The bottom toothed part340moves up and down relative to the drive shaft140because of the rollers350in the first and second grooves332,344. Thanks to the rollers350located between the first and second grooves332,344, the bottom toothed part340moves with almost zero frictional force relative to the drive shaft330. Accordingly, the desired torque is applied to the object by the torque output device300of the present invention by the cooperation of the resilient member360, the pressure collar370locked to the body310.

The body310includes a grip316formed to the outside thereof so that the users can easily grab and rotate the torque output device300without using a tool such as a wrench.

A first seal302is located between a top of the top toothed part320and the opening312of the body310. A second seal304is located between the pressure collar370and the drive shaft330. A third seal306is located between the pressure collar370and the body310. The body310includes lubricant received therein. As shown inFIG.7, the lubricant provides features of lubrication and heat dissipation.

FIG.8shows a third embodiment of the torque output device400of the present invention, and the torque output device400of the present invention comprises a body410, a top toothed part420, a drive shaft430, a bottom toothed part440, multiple rollers450, a resilient member460, a pressure collar470and a top driving portion480.

In this embodiment, the top toothed part420, a drive shaft430, a bottom toothed part440, multiple rollers450, a resilient member460, a pressure collar470are the same as the previous embodiment, the differences are that the top driving portion480is formed to the top of the body410. The top driving portion480includes an engaging hole482so as to be connected with a wrench, a pneumatic tool or an electric tool. The top driving portion481is integrally formed with the body410. As shown inFIG.8, the body410has a U-shaped cross section. The engaging opening482is formed centrally in the top of the body410.

A first seal402is located between a top of the top toothed part420and the engaging hole482of the top driving portion480. A second seal404is located between the pressure collar470and the drive shaft430. A third seal406is a sealing tape and located between the pressure collar470and the body410. The body410includes lubricant received therein, and the lubricant provides features of lubrication and heat dissipation.