HK1161181B - An apparatus for tightening a fastener having a safety device - Google Patents

Description

Device for tightening a fastener with a securing device

Cross-referencing

This application claims priority from U.S. patent application No. 61/081,765, filed on day 18, 7/2008, and U.S. patent application No. 12/325,815, filed on day 12, 12/2008. The contents of the above-mentioned U.S. application are expressly incorporated herein by reference.

Technical Field

The present invention relates to torque power tools. More particularly, the present invention relates to an apparatus for tightening threaded fasteners with a safety device.

Background

Power tools are known in the art. One such known tool is a pneumatic torque power tool. Other torque power tools are known to be electrically, hydraulically, manually driven, or otherwise powered. Each torque power tool has an applied force and an equal and opposite reaction force. In any torque tool, such as a pneumatic torque tool, a torque multiplier, an electric or hydraulic torque tool, the force is equal to the reaction force in the opposite direction. As tightening of fasteners becomes more demanding, precise or at least uniform bolt loads are required. However, this cannot be achieved by using a striking or impact wrench.

Torque power wrenches require a reaction arm to abut against an adjacent fixture to prevent the tool from turning around the bolt and, instead, to turn the nut. In such torque power tools, the reaction arm is typically connected about an axis and a mechanism is provided to hold the arm steady relative to the tool housing during operation. This can be achieved in a spline, hexagonal or other configuration.

The reason why the torque power tool includes a reaction arm is that: the tool is not capable of tightening and loosening a fastener (e.g., a nut) unless the tool housing is prevented from rotating in the opposite direction. This means that to work properly with a torque power tool, equal and opposite nut turning forces must be transferred. Examples of such known torque power tools, including reaction arms to abut a fixture, are disclosed in U.S. patent No. 6,152,243, U.S. patent No. 6,253,642, and U.S. patent No. 6,715,881, which are incorporated herein by reference.

In known torque power tools with reaction arms, there is a significant risk: during use, if not noticed, the operator's finger or hand may be pinched between the reaction arm and the abutment area. The fixture or abutment area against which the necessary reaction arm abuts can be one of the adjacent nuts, the housing of the installation, the pipe of which the flange is a part, etc.

The operator grasps the tool with the operating hand (which also initiates operation of the torque tool). The hands other than the manipulator are free and may inadvertently move to the reaction arm, or adjacent to the reaction arm, where they may be clamped as the reaction arm moves against the fixture to find its abutment area, while the operator triggers and activates the torque tool with the manipulator. This is one of the greatest risks in making threaded connections with torque-powered tools, and occurs frequently because the reaction force exerted by the tool is in most cases much greater than LBS/FT torque, since the abutment of the reaction arm is typically less than a quarter foot from the axis of rotation of the tool. Such tools have, and will continue to, cause finger amputations.

Injury to the fingers of an idle handset is known to be severe. Such accidents occur frequently and require care. Sometimes, not only does the operator's work stop due to injury, but the entire operation must stop. People around the site where the injury to the worker occurs are often concerned about the injury and the injured operator. Therefore, not only are there operators who have been injured and injured, but the cost of the work or work task and the loss of productivity are significant. For this reason, such work incidents are generally the subject of OSHA reporting requirements.

Disclosure of Invention

It is therefore an object of the present invention to provide a torque power tool which avoids the disadvantages of the prior art.

To achieve this and other objects that will become apparent hereinafter, one aspect of the present invention resides, briefly stated, in an apparatus for tightening and loosening a fastener, the apparatus comprising: means for effecting rotation of the fastener having a trigger operable by one hand of an operator; and a safety device operable by the other hand of the operator and configured such that: in use, the means for effecting rotation can operate, but when only one hand of the operator is used and the trigger is operated, the apparatus cannot work to tighten or loosen the fastener.

According to another aspect of the invention, a reaction arm is connectable to and disconnectable from a housing of the apparatus and configured to abut against an adjacent fixture during operation of the apparatus to prevent rotation of the apparatus about the fastener during tightening or loosening of the fastener, the safety device being configured such that: when the safety device is in use, the reaction arm is non-rotatably connected to the housing and is capable of transmitting a reaction force to the adjacent fixture, but when only one hand of the operator is used and the trigger is operated, the reaction arm is disconnected from the housing and therefore, when disconnected, is not capable of transferring a reaction force to the adjacent fixture.

In addition, a further aspect of the invention resides in an apparatus for tightening and loosening fasteners wherein the safety device includes a handle such that the reaction arm is non-rotatably connected with the housing when the handle is operated by an operator, but automatically disconnected from the housing when only one hand of the operator is used and the trigger is operated.

According to another aspect of the invention, the safety device comprises an engagement element which is substantially located between the reaction arm and the housing and which is displaceable between a first position, in which the engagement element non-rotatably connects the reaction arm and the housing, and a second position, in which the engagement element disconnects the reaction arm from the housing.

The safety device can further comprise a spring device arranged such that: when the handle is operated by the operator, the engagement element moves against a spring force from the second position to the first position, but when the operator releases the handle, the spring means automatically displaces the engagement element back from the first position to the second position.

According to yet another aspect of the invention, the safety device can be configured such that: the means for effecting rotation of the fastener (e.g. a motor) is powered when it is operated by the other hand of the operator, but is not powered when only one hand of the operator is used and the trigger is operated, and the apparatus is not operable to tighten or loosen the fastener. The safety device can be used with any torque powered wrench, including electric, hydraulic, pneumatic, etc.

For example, for a torque power wrench with a fluid operated (hydraulic or pneumatic) drive, the safety device can be configured such that: when it is operated, working fluid is supplied to the means for effecting rotation of the fastener, but when only one hand of the operator is used and the trigger is operated, the supply of working fluid to the means for effecting rotation of the fastener is stopped and the apparatus is not operable to tighten or loosen the fastener.

The novel features believed characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

Drawings

FIG. 1 is a view showing a cross section of a torque power wrench according to one embodiment of the present invention.

FIG. 2 is a view showing the components of the safety of the torque power wrench of the present invention, including the shift rod and the sleeve.

Fig. 3 is a view showing other components of the safety device of the torque power wrench, particularly the shift link, of the present invention.

Fig. 4 is a view showing on an enlarged scale the area where a portion of the reaction arm engages a portion of the tool housing of the torque power wrench of the present invention.

Fig. 5 and 6 are views showing two positions of a safety according to another embodiment of the present invention.

Detailed Description

The hand-held torque power wrench according to the present invention has a housing, indicated with reference numeral 1, which houses a motor 2, which motor 2 can be in the form of a pneumatic, hydraulic, electric or the like motor. The drive element 3 is rotationally driven by the motor 2 and engages a fastener to be tightened or loosened, so that, but when the motor 2 is activated, the drive element 3 rotates and causes the corresponding fastener to rotate. The torque power wrench may be provided with a torque intensifying device to increase the torque output from the drive motor 2 to the drive element 3. The torque intensifier means may be formed as a planetary gear, which is located within the housing 1 but not shown in the figures.

The torque power wrench further has a handle 4 for holding the torque power wrench in place by one hand of an operator, and a trigger 5, wherein the trigger 5 is for actuating the torque power tool by the one hand of the operator. The handle 4 is connected to the housing 1, for example, in a non-movable manner. When the operator holds the grip 4 and pulls the trigger 5, the drive motor 2 is started.

The torque power tool further has a reaction arm for abutting an adjacent fixture and transmitting a reaction force generated during operation to the adjacent fixture. The reaction arm has a distal end portion 6 and a proximal end portion 7, wherein the distal end portion 6 is configured to abut the fixture to prevent rotation of the tool about the fastener; the proximal portion 7 can be connected and disconnected from the housing 1 of the torque power wrench as will be explained below. The distal portion 6 and the proximal portion 7 of the reaction arm are connected to each other such that they cannot rotate relative to each other about the rotational axis a of the drive element 3.

The torque output of a hand-held torque power wrench according to the present invention exceeds the torque output that the operator's hand can counteract. In other words, the operator cannot prevent the rotation of the housing of the tool under the action of a reaction force opposite to that provided by the driving element 3; in order for the torque power wrench of the present invention to work, the reaction arm must always be in operation. The reaction arm must be connected to the housing in such a way that it cannot rotate about the axis a of the housing 1 and the drive element 3 and must abut against an adjacent fixture.

According to the invention, the torque power wrench is provided with a safety device which can be operated by the other hand of the operator and which is designed to: the torque power wrench is capable of tightening or loosening a fastener when operated by the other hand of the operator; but is not able to tighten or loosen the fastener when the operator holds the torque power wrench in place by using only one hand to hold the handle 4 and pull the trigger 5.

According to an example embodiment of the invention disclosed in the present application, the safety device is configured such that: when operated by the other hand of the operator, the reaction arm is connected to the housing and can abut against an adjacent fixture during operation of the torque power wrench, thereby preventing the housing of the power torque wrench from rotating about the fastener during tightening and loosening of the fastener. However, when the safety device is not operated by the other hand of the operator, the reaction arm is disconnected from the housing, and therefore, in the latter case, the reaction arm cannot transfer the reaction force to the adjacent fixture.

As can be seen from fig. 1 and 4, the distal part 7 of the reaction arm is provided with axially longer internal splines 8, while the part of the housing 1 extending through the interior of the distal part 7 is provided with axially shorter external splines 9 and is configured such that the splines 8 and 9 are radially spaced from each other. The securing means described above comprise an engaging element, for example formed as a ring 10, wherein the ring 10 is movable in axial direction and has external splines 11 and internal splines 12, wherein the external splines 11 are for example always engaged with the internal splines 8 of the distal end portion 7 of the reaction arm and the internal splines 12 are for example engageable and disengageable with the splines 9 of the portion of the housing 1 extending through the interior of the distal end portion 7. Reference numeral 20 denotes a support member disposed in this region.

In the position shown in fig. 1, the ring 10 is displaced axially downwards so that its splines 12 do not engage with the splines 9 of the housing, and therefore the distal end portion 7 of the reaction arm is not connected to the housing 1 in such a way that it cannot rotate about the axis a. In order to connect the reaction arm to the housing in such a way that it cannot rotate about the axis a, the ring 10 is displaced axially upwards so that not only its splines 11 engage with the splines 8 of the reaction arm, but also its splines 11 engage with the splines 9 of the housing. The reaction arm is thus connected to the housing in such a way that it cannot rotate about the axis a. In this position, the torque power wrench can work when the distal end portion 6 or reaction arm abuts against an adjacent fixture during operation of the torque power wrench, since the reaction torque output that cannot be counteracted by the operator's hand is counteracted by the reaction arm abutting against the adjacent fixture.

In order to displace the ring 10 axially upwards to provide engagement of the reaction arm with the housing, the operator operates one leg of the handle 13 so that the other leg of the handle raises the displacement rod 15 via the kinematic chain 14. The shifting rod 15 raises the sleeve 16, which in turn raises the link 17, and then the link 17 raises the shifter 18 connected to the ring 10, so that finally the ring 10 is raised. As explained above, when the ring 10 is displaced upwards, it provides a connection of the reaction arm to the housing, so that the reaction arm starts to be connected to the housing in such a way that it cannot rotate about the axis a.

It is therefore believed that it should already be understood that a torque power wrench may only operate if the following two actions occur: the operator holds the torque power tool's handle 4 in place in one hand and pulls the trigger 15 while the operator operates the safety by acting on the handle 13 with the other hand so that his other hand cannot be in the area of the reaction arm.

When the operator does not operate the handle 13 with his other hand, the return spring 19 (which is tensioned when the handle 13 is operated) relaxes. This causes the elements 16, 17 and 18 to be displaced axially downwards and the ring 10 to be displaced axially downwards as well, so that the splines 12 of the ring 10 are disengaged from the splines 9 of the housing and the reaction arm is no longer connected to the housing in a non-rotatable manner.

A safety for a hand-held torque power wrench according to another embodiment of the present invention may be formed, for example, such that: when the operator's other hand operates the safety, power is supplied to the motor 2, but when the operator uses only one hand to hold the torque power wrench in place by holding the handle 4 and pulling the trigger 5, the power supply to the motor 2 is interrupted and the torque power wrench cannot be operated to tighten or loosen a fastener. The safety device can be used with torque power wrenches with different types of drives, such as electric, pneumatic, hydraulic and others. An example of this embodiment of the invention is shown in figures 5 and 6, figures 5 and 6 showing the safety in two different positions.

In this embodiment, the torque power wrench has means for supplying a working fluid (liquid or gas) to the motor 21, wherein the motor 21 is formed for example as a pneumatic motor and is provided with a directional valve 22. The means for supplying the working fluid includes a fluid inlet passage 23, and the working fluid is supplied through the fluid inlet passage 23. The discharge channel for evacuating the working fluid is indicated with 24.

The safety device according to the invention comprises a rotatable handle 25, the handle 25 being intended to be held by the other hand of the operator and carrying a return spring 26. The operator acts on the upper arm of the handle 25 while its lower arm is connected to a rod 27, wherein the rod 27 slides in a guide bush 28 and is connected to a piston 29. The piston 29 can be moved transversely into the passage 23 between the position shown in fig. 5 and the position shown in fig. 6, wherein in the position shown in fig. 5 the piston 29 closes the through opening of the passage 23 and prevents the working fluid from flowing into the air motor 21; in the position shown in fig. 6, the piston 29 opens the opening into the passage 23 to allow the working fluid to flow into the air motor 21.

In order to displace the rod 27 and the piston 29 from the position shown in fig. 5 to the position shown in fig. 6, the operator must hold the handle with his other hand and rotate it (e.g., clockwise) so that the through opening of the access passage 23 is opened, working fluid is supplied to the air motor 21 and the torque power wrench can be operated. However, when the operator removes his other hand from the handle 25, the spring 26 pushes the handle in a counter-clockwise direction, the inner leg of the handle 25 displaces the rod 27 and the piston 29 to the position shown in fig. 6, in which the piston 29 closes the through opening of the inlet channel 23, the working fluid no longer flows into the air motor 21, and the torque wrench is not operated.

It is correspondingly clear that other embodiments are also possible for the safety device according to the invention, which is designed such that the torque power wrench only works if: the operator not only holds the torque power wrench and pulls the trigger with one hand, but the operator also operates the torque power wrench with the other hand. The torque power wrench ceases to operate when the operator's other hand is not being used to actuate a component of the torque power wrench.

It will be understood that each of the elements described above, or two or more together, may also be used in other types of constructions differing from the types described above.

While the invention has been illustrated and described in connection with the example of a torque power tool with reaction arm safety control, it is not intended to limit the invention to the particular construction illustrated, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that: others can readily adapt it for various applications by applying current knowledge without omitting features that, from the standpoint of prior art, fairly constitute a general or specific aspect of this invention.

The novel features believed protected by the patent are set forth in the appended claims.

Claims (6)

1. An apparatus for tightening and loosening a fastener, the apparatus comprising:

-means for carrying out the rotation of the fastener, having a trigger (5) operable by one hand of an operator; and

a safety operable by the other hand of the operator and configured such that: the means for effecting rotation of the fastener can be operated when the safety device is in use, but the apparatus cannot be operated to tighten or loosen the fastener when the operator uses only one hand and the trigger (5) is operated;

wherein the apparatus comprises a reaction arm connectable to and disconnectable from a housing (1) of the apparatus and configured to abut against an adjacent fixture during operation of the apparatus to prevent rotation of the apparatus about the fastener during tightening or loosening of the fastener, the safety device being configured such that: when the safety device is in use, the reaction arm is connected to the housing (1) in a non-rotatable manner and is capable of transmitting a reaction force to the adjacent fixture; however, when the operator uses only one hand and the trigger (5) is operated, the reaction arm is disconnected from the housing (1), and therefore, when disconnected, cannot transfer reaction forces to the adjacent fixture.

2. The device according to claim 1, wherein the safety means comprises a handle (13) such that the reaction arm is non-rotatably connected with the housing (1) when the handle (13) is operated by the operator, but automatically disconnected from the housing when the operator uses only one hand and the trigger (5) is operated.

3. The device according to claim 2, wherein the safety means comprise an engagement element (10) located substantially between the reaction arm and the housing (1) and displaceable between a first position, in which it connects the reaction arm and the housing (1) in a non-rotatable manner, and a second position, in which it disconnects the reaction arm from the housing (1).

4. A device according to claim 3, wherein the safety means comprise spring means (19) arranged such that: the engagement element (10) moves from the second position to the first position when the handle (13) is operated by the operator, but the spring means (19) automatically repositions the engagement element (10) from the first position to the second position when the operator releases the handle (13).

5. An arrangement as claimed in claim 4, wherein the engagement element (10) is substantially annular and has an engagement formation (11, 12) permanently engageable with an engagement formation (8, 9) of the housing (1) or the reaction arm, the engagement element further having an engagement formation engageable with and disengageable from the engagement formation of the other of the housing (1) and the reaction arm in the first position and in the second position, respectively.

6. The apparatus of claim 1, wherein the apparatus comprises: a housing containing said means for effecting rotation of said fastener; and a handle for holding the device in place with one hand of the operator.