Patent Publication Number: US-8522895-B1

Title: Power tool

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 60/966,609 filed Aug. 29, 2007, which is incorporated by reference herein. 
    
    
     FIELD OF INVENTION 
     The present invention relates to an apparatus for reducing the vibrations that are transferred from a power tool to the user for ergonomically improved positioning in relation to the user for stress and injury reduction. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     No federal funds were used to develop or create the invention disclosed and described in the patent application. 
     REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISK APPENDIX 
     Not Applicable 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  provides a perspective view of an exemplary embodiment of the power tool. 
         FIG. 2  provides a side view of the exemplary embodiment of the power tool. 
         FIG. 3  provides a front view of the exemplary embodiment of the power tool. 
         FIG. 4  provides a top view of the exemplary embodiment of the power tool. 
         FIG. 5  provides a side view of the power tool in relation to a user during operation. 
         FIG. 6  provides a side view of the prior art tool in relation to a user during operation. 
         FIG. 7  provides an exploded view of the exemplary embodiment shown in  FIG. 1 . 
         FIG. 8A  provides a detailed view of the air feed system of the exemplary embodiment of the power tool. 
         FIG. 8B  provides a detailed view of the air delivery system of the exemplary embodiment of the power tool. 
         FIG. 9  provides a perspective view of a second embodiment of the power tool. 
     
    
    
     BACKGROUND 
     Many types of reciprocating power tools are presently available. However, most such power tools, such as those disclosed in U.S. Pat. No. 6,705,409, include one handle opposite the end of the power tool to which the work piece is connected. This configuration is undesirable for several reasons. First, when the user&#39;s wrist, elbow, and/or shoulder are positioned at an extreme angle as the prior art orientations require, the force transferred to the user from the power tool is not evenly disbursed to the user. To properly position the work piece of the prior art power tool, the user&#39;s hand must be positioned in close proximity to the user&#39;s shoulder with the user&#39;s elbow positioned behind the user&#39;s chest. This position is similar to the position of those anatomical structures if the user were lying face down with the user&#39;s hands placed flat against the floor approximately shoulder-width apart. 
     If the user&#39;s wrist, elbow, and/or shoulder are positioned so that the user&#39;s wrist, elbow, and/or shoulder are at the limit of travel for the user&#39;s hand, nearly the entire force transferred from the power tool to the user&#39;s hand is subsequently transferred through the user&#39;s wrist, elbow, and shoulder to be dispersed by the user&#39;s body. When those anatomical structures are in the above-described position, the relevant tendons, ligaments, muscles, and other structures are substantially at the limit of travel and not able to absorb any further energy. Subsequently, when the entire force from the power tool  1  is transferred through those anatomical structures, the force will tend put an undue amount of stress onto those anatomical structures, often resulting in damage. The situation is analogous to placing an additional load on a spring that is already stretched to its limit; additional load either causes the spring to break or deforms and damages the spring so that it no longer performs properly. Placing the handles as shown in the prior art requires that the user bend the user&#39;s wrists, elbows, and shoulders to place the handle in close proximity to the user&#39;s chest to properly position the work piece and operate the power tool. 
     
       
         
           
               
            
               
                   
               
               
                 DETAILED DESCRIPTION - LISTING OF ELEMENTS 
               
            
           
           
               
               
               
            
               
                   
                 ELEMENT DESCRIPTION 
                 ELEMENT # 
               
               
                   
               
            
           
           
               
               
               
            
               
                   
                 Power Tool 
                 1 
               
               
                   
                 Work Piece 
                 2 
               
               
                   
                 First Handle 
                 3 
               
               
                   
                 Second Handle 
                 4 
               
               
                   
                 Tool Body 
                 5 
               
               
                   
                 Tool Body First End 
                 6 
               
               
                   
                 Tool Body Second End 
                 7 
               
               
                   
                 Handle Distal End 
                 8 
               
               
                   
                 Internal Portion 
                 9 
               
               
                   
                 User 
                 10 
               
               
                   
                 Throttle lever 
                 11 
               
               
                   
                 Receiver Cup 
                 12 
               
               
                   
                 Clutch Band 
                 13 
               
               
                   
                 Exhaust Shield 
                 14 
               
               
                   
                 Valve Seat 
                 15 
               
               
                   
                 Valve 
                 16 
               
               
                   
                 Washer 
                 17 
               
               
                   
                 Top Valve Seat 
                 18 
               
               
                   
                 Piston 
                 19 
               
               
                   
                 Pneumatic Motor 
                 20 
               
               
                   
                 Retainer 
                 21 
               
               
                   
                 User&#39;s Hands 
                 22 
               
               
                   
                 Barrel 
                 23 
               
               
                   
                 First Air Passage 
                 24 
               
               
                   
                 Second Air Passage 
                 25 
               
               
                   
                 Tool Feed 
                 26 
               
               
                   
                 Throttle Valve 
                 27 
               
               
                   
                 Air Inlet 
                 28 
               
               
                   
                 Cavity 
                 30 
               
               
                   
                 Pneumatic Percussive Mechanism 
                 31 
               
               
                   
                 Sight Line 
                 32 
               
               
                   
                 Support Ring 
                 33 
               
               
                   
               
            
           
         
       
     
     Before the various embodiments of the present invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that phraseology and terminology used herein with reference to device or element orientation (such as, for example, terms like “front”, “back”, “up”, “down”, “top”, “bottom”, and the like) are only used to simplify description of the present invention, and do not alone indicate or imply that the device or element referred to must have a particular orientation. In addition, terms such as “first”, “second”, and “third” are used herein and in the appended claims for purposes of description and are not intended to indicate or imply relative importance or significance. 
     DETAILED DESCRIPTION 
     Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views,  FIG. 1  provides a perspective view of an exemplary embodiment of the power tool  1 . In the embodiments pictured herein, the present invention is applied to vibration-isolated power tools similar to those disclosed in U.S. Pat. Nos. 5,896,934, 6,705409, and 6,955,230, which patents are incorporated by reference herein. Most commonly, the power tool  1  will be what is generally referred to as either a chipping hammer or rivet buster. However, the present invention is not limited by the specific embodiments pictured or described herein and may be applied to tools other than those disclosed in the patents referenced herein. 
     As disclosed herein, a tool body  5  houses the internal portion  9  of the power tool  1 . The internal portion  9  and tool body  5  are configured so that the internal portion  9  fits within a cavity  30  formed in the tool body  5 . The tool body  5  may also include a sight line  32 , which is a cutaway portion of the tool body  5  along the longitudinal axis of the tool body  5  to allow the user  10  better visibility of the work surface, which is best shown in  FIG. 4 . 
     The internal portion  9  may have several different embodiments, depending on the specific application for the power tool  1 . In general, the internal portion  9  serves to convert electrical energy or potential energy (such as a compressed fluid) into mechanical energy, as is known to those skilled in the art. The internal portion  9  operatively communicates this mechanical energy to the work piece  2 . A more detailed view of an internal portion  9  configured as a pneumatic percussive mechanism  31  is shown in  FIG. 7 , which is described in detail below and well known to those skilled in the art. 
     In an embodiment not shown herein, the internal portion  9  may also be configured as an electric percussive device (not shown), as is well known to those skilled in the art. In certain embodiments, the internal portion  9  includes a barrel  23  to which the work piece  2  is coupled. In one embodiment, the internal portion  9  and the barrel  23  are integrally formed.  FIG. 9  shows an embodiment of the power tool  1  that includes a barrel  23  longer and more robust than the barrel  23  on the power tool  1  depicted in  FIGS. 1-5 . The power tool  1  is not limited by the specific size and/or dimensions of the barrel  23  or the internal portion  9 , and embodiments different from those pictured and described herein are within the scope of the present disclosure. Generally, the size of the internal portion  9  and/or barrel  23  determines the application and capacity of the power tool  1 . 
     As the size of the internal portion  9  and/or barrel  23  increases to accommodate a more forceful work piece  2 , the size of the tool body  5  may increase by a corresponding amount. Accordingly, in certain applications the power tool  1  may be large enough so that supplemental supports are required during use. In those embodiments, the tool body  5  may be configured with a support ring  33  on the upper side so that the power tool  1  may be suspended by a chain or cable (See  FIG. 5  by way of illustration). In this manner, the user  10  need not support the majority of the weight of the power tool  1 . The support ring  33  may be mounted on a track (not shown) formed on the top of the tool body  5  so that it may be moved along the longitudinal axis of the power tool  1 . In this way, the angle of the power tool  1  may be manipulated by the position of the support ring  33 . The position of the support ring  33  in the track (not shown) may be secured through the use of set screws (not shown) engaging the tool body  5 , or any other device known to those skilled in the art that is suitable for the specific application of the power tool  1 . 
     As shown in  FIGS. 1-5 , the user interface portion of the power tool  1  is in a more convenient position than the position of the user interface portion of similarly functioning tools of the prior art. In the embodiments shown herein, the user interface portion consists of a first handle  3  and a second handle  4  positioned on the tool body  5  towards the work piece  2 , which end of the tool body  5  is referred to herein as the tool body second end  7 . In the embodiments pictured herein, the first and second handles  3 ,  4  are angled with respect to one another in such as way so that the angle between them is approximately 120 degrees. However, the angle between the first and second handles  3 ,  4  may be as great as 180 degrees (which would form a T-shape) or as little as 20 degrees, depending on the specific application. 
     A work piece  2  is in operative communication with the internal portion  9  of the power tool  1  through the retainer  21  (shown in  FIG. 7 ). As is well known to those skilled in the art, the work piece  2  serves to communicate mechanical energy from the internal portion  9  and/or barrel  23  to the surface on which work is to be done. As used herein, the term “barrel” is meant to include the entire internal portion  9  that powers the power tool  1  and/or the portion of the power tool  1  protruding from the tool body  5 . The power tool  1  may be employed with any type of work piece  2  necessary for a specific task, such as a chisel bit, a drill bit, hammer bit, or other type of work piece  2 . Certain work pieces  2  may require a different coupling mechanism, and therefore may have a different type of barrel  23  on the internal portion  9  protruding from the tool body  5 . As shown in  FIG. 9 , the power tool  1  may be configured to be used as a large reciprocating tool, commonly referred to as a “rivet buster.” However, the power tool  1  may also be configured to be used as a medium or small reciprocating tool, commonly referred to as a “chipping hammer.” Accordingly, the specific work piece  2  used or specific application of the power tool  1  in no way limits the scope of the present invention. 
     A throttle lever  11  is positioned on either the first or second handle  3 ,  4 , and serves to activate the internal portion  9  to modulate mechanical energy transferred to the work piece  2  (explained in detail below). The throttle lever  11  may be positioned on either the first or the second handle  3 ,  4 , and it may be positioned either towards or opposite the work piece  2  with respect to the user&#39;s position. It is contemplated the most convenient position of the throttle lever  11  will be towards the work piece  2 , in which configuration the user  10  will engage the throttle lever  11  with the user&#39;s fingers. 
     In the embodiment of the power tool  1  pictured in  FIGS. 1-5 , the power tool  1  is pneumatically powered.  FIG. 7  is an exploded view of the internal portion  9  and barrel  23  of the power tool  1 . As shown, the power tool  1  has a throttle lever  11  attached to the first handle  3 . The throttle lever  11  allows the user to control the flow of compressed fluid through a throttle valve  27  (shown in  FIG. 8A ) to engage the pneumatic motor  20  (which engages the pneumatic percussive mechanism  31 ) and vary the speed of operation of the power tool  1 . The work piece  2  in this embodiment is a sharpened end that in combination with the pneumatic percussive mechanism  31  may drive the work piece  2  into and through solid material. The interior of the barrel  23  contains a typical pneumatic percussive mechanism  31  for a reciprocating the power tool  1 , the rear inner end of which (i.e., the end adjacent the tool body first end  6 ) is chucked in the barrel  23  in conventional style by receiver cup  12  through the cooperative interaction of a clutch band  13 , an exhaust shield  14 , a valve seat  15 , a valve  16 , a washer  17 , a top valve seat  18 , a piston  19  and a retainer  21 , which are well known to those of skill in the art. Other embodiments of the internal portion  9  and barrel  23  may be used within the spirit and scope of the present disclosure, and the embodiments thereof pictured and described herein are for exemplary purposes only. Those skilled in the art are well aware that in operation the power tool  1  is subject to a variety of forces, including fore-and-aft, vertical and lateral, and these occur at wide ranges of frequency and amplitude. 
       FIGS. 8A and 8B  disclose and illustrate the compressed fluid supply necessary to motivate the embodiment of the power tool  1  that is pneumatically driven. The compressed fluid supply, which is commonly compressed air, is brought into the power tool  1  through the air inlet  28 . The air inlet  28  is positioned towards the tool body first end  6  so as to not interfere with the user  10  during operation of the power tool  1 . As illustrated in  FIG. 8A , a first air passage  24  having an orientation that is substantially parallel with the longitudinal axis of the powered tool  1  and perpendicular to the longitudinal axis of the handles  3 ,  4  connects the air inlet  28  to the throttle valve  27  located adjacent first handle  3 . The throttle valve  27  may be located adjacent the second handle  4  in an embodiment in which the throttle lever  11  is positioned adjacent the second handle  4 . 
     As illustrated in  FIG. 8B , a second air passage  25  also having an orientation that is substantially parallel with the longitudinal axis of the powered tool  1  and perpendicular to the longitudinal axis of the handles  3 ,  4  connects the throttle valve  27  to the tool feed  26 . The second air passage  25  thereby serves as a conduit for the compressed fluid coming from the throttle valve  27  to the internal portion  9 . The position of air inlet  28  and first and second air passages  24 ,  25  allows the compressed fluid supply for the power tool  1  to be located adjacent the tool body first end  6 , which reduces interference between the user  10  and the power tool  1 . The specific location of the air inlet  28  and first and second air passages  24 ,  25  may vary depending on the particular application of the power tool  1 , and the present disclosure applies to all orientations allowing the compressed fluid supply to be delivered to the internal portion  9  in a manner that reduces interference with the user  10  during operation. 
     In embodiments in which the internal portion  9  is comprised of an electric percussive mechanism (not shown), the positioning of the throttle lever  11  adjacent one of the handles  3 ,  4  towards the tool body second end  7  does not require air passages  24 ,  25  formed in the tool body  5 . Instead, an electrical conduit (such as wire) is simply routed from the electrical current source to a regulator (not shown) or other device for varying the amperage and/or voltage supplied to the electrical percussive mechanism (not shown). The throttle lever  11  would control the position of the regulator (not shown) or other device, which would in turn be electrically connected to the electric percussive mechanism (not shown). Because the electric percussive mechanism used in conjunction with the power tool  1  as disclosed herein is well known to those skilled in the art, it will not be described or explained further for purposes of clarity. 
     Positioning the handles  3 ,  4  towards the tool body second end  7  rather than towards the tool body first end  6  offers several advantages. For example, if the handles  3 ,  4  are symmetrical about the longitudinal axis of the power tool (as depicted in the embodiments herein), the force transferred from the power tool  1  to the user  10  during operation of the power tool  1  is evenly distributed to both of the user&#39;s hands  22 , which subsequently evenly transfers the force to the user&#39;s wrists, elbows, shoulders, and other anatomical structures. In power tools having only one handle, the force transferred from the power tool to the user is almost exclusively distributed on one side of the user&#39;s body. The proximity of the handles  3 ,  4  to the work piece  2  allow the user  2  to more accurately position the work piece  2  and provides the user  10  with more leverage in manipulating the position of the power tool  2  than a similar arrangement in which the handles  3 ,  4  were adjacent the tool body first end  6 . 
     The symmetry of the handles  3 ,  4  provided by the embodiments pictured herein also facilitates increased accuracy when operating the power tool  1  by allowing the user  10  a line of sight along the longitudinal axis of the work piece  2 , which is enhanced in embodiments configured with a sight line  32  in the tool body  5 .  FIG. 4  shows a view of the power tool  1  and work piece  2  available to the user of the power tool  1 . Although the embodiments pictured herein employ a symmetrical orientation of the handles  3 ,  4 , the present invention is not limited to symmetrical orientations. Rather, the present invention includes any orientation of the handles  3 ,  4  on the tool body  5  where the handles  3 ,  4  are placed closer to the tool body second end  7  than they are to the tool body first end  6 . 
     Furthermore, in embodiments not shown herein, the handles  3 ,  4  could be formed as one continuous piece connected to the tool body  5  at a plurality of positions. Such an embodiment may be oriented and fashioned to appear similar to the embodiments pictured herein with a member connecting the handle distal ends  8 . This could be accomplished by a flat band (not shown) configured to engage the outer periphery of the tool body  5  and capable of engaging the tool body  5  so that the flat band (not shown) was not movable with respect to the tool body  5 . In embodiments in which the handles  3 ,  4 , are formed as one continuous piece, the handles  3 ,  4  may be affixed to the tool body  5  at more than two points to increase the durability of the handles  3 ,  4 . 
     User comfort is another advantage of placing the handles  3 ,  4  towards the tool body second end  7 , which is amplified by a symmetrical orientation of the handles,  3 ,  4 . However, a symmetrical orientation of the handles  3 ,  4  is not required to realize the benefits of placing the handles  3 ,  4  towards the tool body second end  7 , which is explained in detail above. As previously explained, when the user&#39;s wrist, elbow, and/or shoulder are required to act as a conduit for the force transferred from the power tool  1  to the user, undue stress is placed on ligaments, muscles, bones, tendons, and/or any other relevant anatomical tissue in the user&#39;s arm. By contrast, when the user  10  is allowed to position the user&#39;s arms in a straighter position (i.e., with the user&#39;s arms extended in front of the user&#39;s body away from the user&#39;s chest), as allowed by the present invention, the user&#39;s wrists, elbows, and shoulders serve to uniformly absorb and disperse a portion of the force created by the power tool  1 . 
     Apart from advantages associated with a symmetrical orientation of the handles  3 ,  4 , positioning the handles  3 ,  4  towards the tool body second end  7  allows the user  10  to correctly position the work piece  2  and use the power tool  1  without the need for the user to position the user&#39;s wrist, elbow, and/or shoulder in an extreme position. Furthermore, with the incorporation of a support ring  33 , the present invention also decreases the user&#39;s workload avoiding user muscle fatigue and exhaustion. 
     The present invention includes many alternative embodiments of varying size and orientation. The internal portion  9 , barrel  23 , and/or tool body  5  are often sized according to the application of the power tool  1 , depending on the force the power tool  1  is required to deliver. Furthermore, depending on the application for which the power tool  1  is designed, the tool body  5 , work piece  2 , and handles  3 ,  4  may be able to withstand forces of varying magnitude. Accordingly, the size of the power tool  1  or any elements thereof, the durability of the materials used to construct the power tool  1  or work piece  2 , and the maximum force the power tool  1  is designed deliver in no way limit the scope of the present invention. Furthermore, and suitable material known to those skilled in the art, including metals, polymers, and/or composite materials, may be used to construct the power tool  1  or any portions thereof for any embodiment described or pictured herein. 
     The power tool  1  is not limited by the specific embodiments pictured or described herein, or the specific work piece  2  the power tool  1  is fashioned to engage. The present invention may be applied to any tool as determined by the needs of the user according to the specific application. Additionally, the scope of the present invention is not limited by whether the handles  3 ,  4  of the specific embodiment are oriented symmetrically along the longitudinal axis of the work piece  2 , or the specific angle formed between the handles  3 ,  4 . The present invention is intended to apply to all similar apparatuses for reducing or more evenly distributing the force transferred to a user  10  of the power tool  1  during operation of a power tool  1 . Modifications and alterations from the described embodiments will occur to those skilled in the art without departure from the spirit and scope of the present invention.