Patent Publication Number: US-11654544-B2

Title: Insert for a power tool housing

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates generally to power tools for applying torque to a work piece. More particularly, the present invention relates to an insert that reduces creep and/or stress relaxation in a housing of a power tool. 
     BACKGROUND OF THE INVENTION 
     Many tools are powered by pneumatic air or hydraulic fluid. Impact wrenches, for example, can use pressurized air to impart torque to a work piece to loosen or tighten the work piece. These tools rely on a clamping force to ensure that the motor disposed in a housing does not leak fluid, such as, for example, air or hydraulic fluid. Fluid leaks negatively affect output power. Typically, the clamping force is created by coupling a housing and a nose housing using fasteners, such as screws. However, with the increased use of plastic components, including housings, the ability to maintain the necessary clamping force through the life of the tool is compromised due to the occurrence of creep and/or stress relaxation. 
     Existing pneumatic and hydraulic tools include ribs disposed on a rear portion of the housing to reduce and better distribute stress to prevent the occurrence of creep and/or stress relaxation. However, these ribs increase the dimensions and weight of the tool. Added weight and size negatively affects usability of power tools. 
     SUMMARY OF THE INVENTION 
     The present invention relates broadly to an insert, also referred to as a compression limiter, coupled to a housing and adapted to receive a fastener that couples to a nose housing. The insert provides sufficient area to contact a head of the fastener. The insert and nose housing are composed of a material that is less susceptible to creep and/or stress relaxation for the clamping force magnitudes commonly used. For example, the insert and nose housing can be composed of metal, and the housing can be composed of plastic. 
     In particular, the present invention broadly comprises a tool having a motor. The tool comprising a nose housing, a housing including an aperture adapted to receive a fastener that is adapted to apply a clamping force, an insert disposed within the aperture and having opposing first and second sides. The first side is adapted to be disposed proximal to a head of the fastener, and the second side is adapted to be disposed proximal to the motor. 
     In another embodiment, the present invention can further broadly comprise an insert adapted to be disposed in a housing aperture of a tool. The insert comprises first and second opposing sides, an insert aperture extending through the insert and that is adapted to receive a fastener, and an exterior surface corresponding to the housing aperture. The first side is adapted to be disposed proximal to a head of the fastener that applies a clamping force, and the second side is adapted to be disposed proximal to a motor of the tool. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For the purpose of facilitating an understanding of the subject matter sought to be protected, there are illustrated in the accompanying drawings embodiments thereof, from an inspection of which, when considered in connection with the following description, the subject matter sought to be protected, its construction and operation, and many of its advantages should be readily understood and appreciated. 
         FIG.  1    is a perspective view of a tool incorporating an insert, according to an embodiment of the present invention. 
         FIG.  2    is an exploded, disassembled perspective view of portions of the tool of  FIG.  1   . 
         FIG.  3    is cross-sectional view of a housing of the tool of  FIG.  1   , along line  3 - 3  of  FIG.  1   . 
         FIG.  4    is a perspective view of an insert, according to an embodiment of the present invention. 
         FIG.  5    is a perspective view of an insert, according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     While the present invention is susceptible of embodiments in many different forms, there is shown in the drawings, and will herein be described in detail, embodiments of the invention, including a preferred embodiment, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the present invention and is not intended to limit the broad aspect of the invention to any one or more embodiments illustrated herein. As used herein, the term “present invention” is not intended to limit the scope of the claimed invention, but is instead used to discuss exemplary embodiments of the invention for explanatory purposes only. 
     The present invention broadly comprises an insert for a housing of power tool, such as, for example, a pneumatic or hydraulically powered impact wrench. The insert is disposed in the housing to contact a fastener used to apply a clamping force. The insert is composed of a material that resists creep and/or stress relaxation. This allows for the tool to maintain the clamping force applied by the fastener over the life of the tool, thereby reducing the possibility of fluid leaks. 
     Referring to  FIGS.  1 - 5   , a tool  100 , such as a pneumatic or hydraulic impact wrench, includes a housing  102 , a trigger  104  disposed adjacent to a handle  106  of the housing  102 , and a nose housing  108  adapted to couple to an end of the housing  102 . The trigger  104  can be actuated by a user to cause fluid, such as, for example, pressurized air or hydraulic fluid, from an external supply to operate the tool  100  to drive an output lug  130  in either one of first and second rotational directions (e.g., clockwise and counterclockwise). The output lug  130  can be coupled to other devices, such as a socket, to apply torque to a work piece, such as, for example, a screw or bolt, in a well-known manner. The trigger  104  can be biased such that the user can depress the trigger  104  inwardly, relative to the tool  100 , to cause the tool  100  to operate, and release the trigger  104 , wherein the biased nature of the trigger  104  causes the trigger  104  to move outwardly, relative to the tool  100 , to cease operation of the tool  100 . 
     The housing  102  is adapted to house a motor  132  and includes housing apertures  110  adapted to respectively allow fasteners  112  to pass therethrough. The fasteners  112  extend longitudinally through the housing  102  and are threadably coupled to the nose housing  108 . In an embodiment, the housing  102  is composed of a plastic material. The housing  102  is coupled to the nose housing  108  via the fasteners  112 . The fasteners  112  collectively apply a clamping force to restrict fluid, such as hydraulic fluid or air, from leaking through joints of the motor and/or an interface between the nose housing  108  and the housing  102 . In an embodiment, a gasket  134  is disposed in the interface between the nose housing  108  and the housing  102 . 
     Inserts  114  are disposed in the housing apertures  110  of the housing  102  and have first  120  and second  122  opposing sides and an insert aperture  124  sized to allow one of the fasteners  112  to pass therethrough. The inserts  114  can have a substantially circular cross-section as shown, although the invention is not limited to circular cross-sections and other suitable cross-sections may be used. The cross-section of the inserts  114  has sufficient area to contact a head of the fastener  112 . For example, the first side  120  of the insert  114  is adapted to abut the head of one of the fasteners  114 . The second side  122  of the insert  114  is adapted to abut the motor  132  (such as an end or other part of a casing of the motor  132 ), thereby transferring the clamping force from the fastener  114  to the motor  132  and removing the housing  102  from the load path of the clamping force. In an embodiment, the inserts  114  are bonded to the housing  102  by heat staking. Other suitable methods for bonding the inserts  114  to the housing  102  can be used. The inserts  114  are composed of a material that is resistant to creep and/or stress relaxation, such as, for example, a metal material. The nose housing  108  can also be composed of a material that is resistant to creep and/or stress relaxation, such as, for example, a metal material. 
     The inserts  114  include an exterior surface  126  that corresponds to an interior surface of the housing apertures  110 . In an embodiment, the inserts  114  include a chamfer  116 . The chamfer  116  provides a seat for a seal  118  that can be disposed between the head of the fastener  112  and the first side  120  of each of the inserts  114 . In an embodiment, the seal  118  is an elastomeric O-ring. Referring to  FIG.  5   , in another embodiment, the insert  214  includes one or more barbs  228  disposed on the exterior surface  226 . The barbs  220  respectively grip an interior surface of the housing apertures  110  and restrict the insert  214  from backing out of the housing aperture  110 . The insert  214  may also include the chamfer  116 . 
     By bonding inserts  114 / 214  into the housing  102 , and disposing the motor  132  between the inserts  114 / 214  and the nose housing  108 , the housing  102  can be removed from the load path of the clamping force applied by the fasteners  112 . Therefore, the entire load path of the clamping force is through components composed of a material that is resistive to creep and/or stress relaxation, thereby reducing the possibility for fluid leaks to develop. 
     As discussed herein, the tool  100  can be a pneumatic tool such as an impact wrench. However, the tool  100  can be any pneumatically or hydraulically powered or hand-held tool, such as a ratchet wrench, torque wrench, impact wrench, drill, saw, hammer, or any other tool. 
     As used herein, the term “coupled” or “communicably coupled” can mean any physical, electrical, magnetic, or other connection, either direct or indirect, between two parties. The term “coupled” is not limited to a fixed direct coupling between two entities. 
     The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. While particular embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the broader aspects of the inventors&#39; contribution. The actual scope of the protection sought is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.