Abstract:
A preferred embodiment of the present invention is directed to a detachable flexible handle for a power hand tool and an attachment system associated with the handle and the tool for releasably attaching either a rigid or the flexible handle to the power hand tool. The system has housing attachment recesses on the tool that receive attachment clips located at opposite end portions of the flexible handle or structure of a rigid handle.

Description:
FIELD OF THE INVENTION 
     The present invention is related to power hand tools. More particularly, the present invention is related to handles for power hand tools and a releasable attachment system for coupling the handles to the housing of the hand tool. 
     BACKGROUND OF THE INVENTION 
     Most power hand tools have handles of one form or another to facilitate their use. Exceptions to this may be found in power hand tools that are small enough for the user to conveniently hold them in one hand. When they are slightly larger, some power tools have handles that are detachable so that the user can choose whether a handle is convenient or not and either remove or attach it. The use of a handle may be desirable on power hand tools that are known in the building trade as spiral saws, i.e., cylindrical units that use a bit that closely resembles a drill bit, but which has cutting surfaces on the sides of the bit for cutting holes in dry wall for example. A detachable handle may be desirable for use with such spiral saws so that a user can comfortably hold the tool in different positions. Also, since such hand tools may require significant force to move it about during cutting of certain materials such as drywall. In those circumstances, two handed operation whereby the user directly grips the tool housing may be most convenient. It may be inconvenient, however, to grip the tool housing directly or to use two hands when using the tool to operate in other positions. When using the tool to cut into an overhead surface, for example, it may be useful to have a handle attached to the tool for gripping. The provision of a detachable handle is advantageous in that a user may have the option of holding the tool directly by its housing or by the handle. 
     It is also desirable for such detachable handles to be easily attached and removed without the use of separate tools. At least one power rotary cutting hand tool has a rigid handle that has an attachment mechanism that engages a pair of recesses in the housing of the tool to firmly hold the tool and yet can be easily removed. That structure is disclosed in U.S. Patent (Ser. No. 10/161,944) entitled POWER TOOL HANDLE and assigned to the Robert Bosch Tool Corporation of Broadview Ill. While artisans may prefer not to have a rigid handle on the tool during some uses, it may be convenient and desirable to have a flexible handle attached to the tool during some operations and/or for carrying the tool between operations. 
     SUMMARY OF THE INVENTION 
     A preferred embodiment of the present invention is directed to a rotary hand tool having a flexible handle and an attachment system associated with the handle and the tool that enables easy attachment and removal of the flexible handle. The system has housing attachment recesses on the tool that receive attachment clips located at opposite end portions of the flexible handle. The attachment recesses are compatible for attaching a generally C-shaped detachable rigid handle which has opposite end portions with a gripping portion therebetween. The rigid handle has a release lever in one end portion and a fixed attachment arm on the other end portion for engaging the spaced apart attachment recesses of the tool housing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a preferred embodiment of a power hand tool having a flexible handle attached thereto; 
     FIG. 2 is a plan view of the embodiment shown in FIG. 1; 
     FIG. 3 is a front view of an attachment clip of the flexible handle shown in FIGS. 1 and 2; 
     FIG. 4 is a side view of the attachment clip shown in FIG. 3; 
     FIG. 5 is a side view of the embodiment shown in FIG.  1  and particularly illustrating the attachment recesses thereof; 
     FIG. 6 is an enlarged view of one of the attachment recesses of the embodiment shown in FIG. 5; 
     FIG. 7 is a cross-section taken generally along the line  7 — 7  in FIG. 6; 
     FIG. 8 is a cross-section taken generally along the line  8 — 8  of FIG. 6; 
     FIG. 9 is a plan view of the other of the attachment recesses shown in FIG. 5; 
     FIG. 10 is a cross-section taken generally along the line  10 — 10  of FIG. 9; 
     FIG. 11 is a cross-section taken generally along the line  11 — 11  of FIG. 9; and 
     FIG. 12 is a side view of a rigid handle shown with portions removed to illustrate the manner in which the rigid handle is attachable to the power hand tool. 
    
    
     DETAILED DESCRIPTION 
     A preferred embodiment of the rotary power hand tool of the present invention is shown in the drawings. While the preferred embodiment is shown in connection with a rotary power hand tool that is generally cylindrical in overall shape and is relatively small so that an artisan can operate the hand tool with one or both hands without a handle or it may have a detachable rigid handle provided with the tool. If the rigid handle is removed from the body of the tool, the user must affirmatively grasp the body of the tool during use and while carrying it. If there is no convenient place for an artisan to put the tool down between operations, it may be convenient for the tool to have a flexible handle or longer strap so that the user could use to easily hang the tool on his hand or arm at least temporarily without consciously gripping the tool. The preferred embodiment of the present invention facilitates various handle configurations so that the user can choose between the various configurations as he sees fit. 
     Turning now to the drawings, and particularly FIGS. 1 and 2, a tool indicated generally at  20 , is shown to have a generally cylindrical elongated housing  22  in which a motor is located. It has a rotatable output shaft  24  (see FIG. 5) to which a cutting bit  26  or other tool is attached. An adjustable depth guide  28  may be provided that fits on the nose of the tool for controlling the depth of cut of the bit  26 . A common use of this type of tool is to cut openings in drywall for light fixtures, switch boxes and electrical outlets and the like with the bit  26  being a spiral side cutting bit. 
     In accordance with the preferred embodiment of the present invention, a flexible handle, indicated generally at  30 , is provided and can be attached to the housing at approximately the same locations as a rigid handle  32  shown in FIG. 12 can be attached. The rigid handle has a pivotable lever  34  at the upper end thereof and an attachment arm  36  at the bottom end thereof. The attachment arm  36  is curved downwardly to engage a flange in an attachment recess, indicated generally at  38  in FIG. 5, and the lever  34  has a hook  40  that engages a similar flange to be described that is located at an upper attachment recess, indicated generally at  42  in FIG.  5 . The lever  34  can be manipulated by raising a cover  44  that reveals a thumb engaging surface (not shown) which when depressed, causes the lever  34  to be moved upwardly to disengage from a shelf (to be described later) enabling the handle  32  to be removed from the tool  20 . 
     Returning to FIGS. 1 and 2, the flexible handle  30  comprises a long thin strap  50  that is attached to attachment clips  52  on opposite end portions thereof. The width of the strap  50  is approximately ¾ of an inch, but can be wider or narrower as desired. The strap is preferably made of a woven fabric that is strong and durable and which preferably does not absorb moisture and may be made of a synthetic material such as nylon or the like. Each of the attachment clips  52  and  54  are substantially identical in construction and comprise split base portions  56   a  and  56   b  so as to define a gap that facilitates removal of the clip from the housing when desired. Each of the base portions  56   a  and  56   b  merge into a generally transverse side portion  58  with a bridge portion  60  extending between the side portions. A pair of spaced apart prongs  62  extend downwardly from the base portion and each prong has a transverse leg  64 , with the transverse legs pointing away from each other and having a beveled surface  66  that tends to deflect the prongs toward each other when the beveled surface  66  engage surfaces of the housing when the attachment clips are inserted into the recesses  38  or  42 . 
     While the bridge portion  60  is narrower than the side portions  58 , it has a sufficient cross sectional area so that it is relatively strong and provide the necessary biasing force to keep the prongs  62  biased away from each other to maintain engagement with complimentary structure of the recesses  38  and  42 . In this regard, the attachment clips are preferably formed as an integral one piece unit and made of a resilient material that has sufficient strength to support the tool when held by the strap  30  and sufficient strength to keep the prongs in locking engagement with the housing. 
     One of the base segments, e.g.,  56   a , preferably has an L-shaped extension  68  that limits the amount of movement of the sides  58  toward one another when the user squeezes the sides together. To facilitate gripping, a number of raised ribs  70  may be provided on the outer surface of each of the sides  58 . 
     Referring again to FIGS. 1 and 2, the strap  50  includes a lower end portion  72  that loops around the bridge portion  60  and the two layers of the strap in this area are preferably sewn, riveted or otherwise attached together. At the opposite end portion, the strap  50  extends through a buckle  74 , is looped around the bridge portion  60  of the clip  54  and extended back through the buckle  74  as shown. The strap  50  may therefore be adjusted within the buckle  74  to vary the effective length of the handle  30 . The strap  50  also has a pad portion  76  secured to it, with the strap  50  extending through an opening in a bottom portion  78  of the pad  76 . 
     Turning now to the upper attachment recess  42  and referring to FIGS. 6,  7  and  8 , the recess  42  has a bottom surface  80 , as well as a number of walls  82 ,  84 ,  86 ,  88 ,  90 ,  92 ,  94 ,  96 ,  98 ,  100 ,  102  and  104 , which extend from the bottom surface  80  to the outer surface of the housing  22 . While there are a number of decorative bevels at the interface between the outer surface and the walls, the walls are generally perpendicular to the plane of the bottom surface  80 , except for the surface  88 , which as shown in FIG. 8, has a significant curvature. As can be seen from the cross-sections of FIGS. 7 and 8, the walls  82 ,  94  and  100  have openings  106 ,  108  and  110  formed therein, respectively, which respectively form shelves  112 ,  114  and  116  for engagement with the handles  30  or  32 . In this regard, walls  82  and  94  are spaced apart from one another and are opposed to each other and are spaced a distance that is slightly less than the distance between the prongs  62  of the attachment clips  52  so that the transverse legs  64  will engage the shelves  112  and  114  to hold the clip  52  in place. If the flexible handle is removed and the rigid handle  32  attached, the edge  40  of the lever  34  will engage the shelf  116  when it is attached to the housing  22 . 
     With regard to the attachment recess  38 , it is very similar in its construction and the same reference numbers with a prime designation have been given to similar features of it. It should be understood that the arm  36  of the rigid handle  32  engages the shelf  106 ′ when the rigid handle is attached to the tool  20 . 
     While various embodiments of the present invention have been shown and described, it should be understood that other modifications, substitutions and alternatives are apparent to one of ordinary skill in the art. Such modifications, substitutions and alternatives can be made without departing from the spirit and scope of the invention, which should be determined from the appended claims. 
     Various features of the invention are set forth in the following claims.