Patent Publication Number: US-6220129-B1

Title: Dual multi-bit screwdriver

Description:
TECHNICAL FIELD 
     The present invention relates to a dual screwdriver wherein the handle is made of two sections with the rear section being disconnectable from the front section and constituting a stub screwdriver. In particular the two handle sections are interconnected in clamping function fit and a storage magazine is provided about the periphery of the rear wall of the front handle section by cavities having at least a portion thereof formed of a thermoplastic elastomer section which forms part of the handle to provide improved retention of the bits while providing improved torquing by the hand of a user. 
     BACKGROUND ART 
     Multi-bit screwdrivers are known wherein the bits are stored within the handle of the screwdriver and are accessible by disconnecting a portion of the handle. An example of such multi-bit screwdrivers is shown and described in U.S. Pat. No. 4,552,044. With such screwdrivers, it is necessary to change the screwdriver bit every time the screw head has a different shape. Also with such screwdrivers the handle is of a common size and when working in a restricted space that type of screwdriver may not be usable. 
     Dual screwdrivers having a main screwdriver handle and a disconnectable stub end which is convertable to a stub screwdriver is also known as described in U.S. Pat. No. 5,868,048. This particular patent describes a specific system of interlocking the stub end handle section to the main handle section and the bits are merely retained in a loose arrangement in a hollow section of the handle. Accordingly, these bits are easily lost and only a limited amount of bits can be accommodated. 
     U.S. Pat. No. 5,881,615 describes a multi-bit screwdriver wherein bits are secured about the outside of the handle in grooves which are sized and shaped to receive a single bit. The bits have opposed screw engaging heads and are retained in the grooves by sliding panels slidingly connected to the handle. The panels only cover a portion of these grooves. Accordingly, when a person grasps the handle, his hand is exposed to irregularities which makes it very uncomfortable. Also, during the torquing application of the handle, stress is imposed upon these sliding panels which can often break. The panels also break when the screwdriver is dropped on a hard surface. Another disadvantage of such screwdriver handles is that the sliding panels may be accidentally displaced thereby accidentally releasing a bit. Also, if one of these sliding panels break, then the groove is no longer useable and the grasping of the handle is rendered even more uncomfortable to the user&#39;s hand and without storage space the loose bit becomes lost and the utility of the screwdriver is impaired. 
     SUMMARY OF INVENTION 
     It is a feature of the present invention to provide a dual multi-bit screwdriver which substantially overcomes the above-mentioned disadvantages of multi-bit and dual-type screwdrivers of the prior art. 
     Another feature of the present invention is to provide a dual multi-bit screwdriver wherein the handle is made of two sections and wherein the sections can separate from one another to form two screwdrivers having handles and shafts of different lengths. 
     Another feature of the present invention is to provide a dual multi-bit screwdriver having a two section handle and wherein the sections are disconnectable from one another by exerting a pulling force and wherein when disconnected provide access to a screwdriver bit magazine protected by the stub handle section. 
     Another feature of the present invention is to provide a dual screwdriver having a multi-bit capability. 
     Another feature of the present invention is to provide a dual multi-bit screwdriver wherein the screwdriver bit magazine has at least a section thereof provided with a pliable thermoplastic elastomer to provide frictional retention against the bit and wherein the thermoplastic elastomer also extends in the outer handle surface to provide improved friction retention with the hand of a user person to improve torquing the torque transmitting shaft of the main screwdriver body and the stub screwdriver body. 
     According to the above features, from a broad aspect, the present invention provides a dual multi-bit screwdriver which comprises a handle having a front and a rear handle section removably interconnected together. An elongated torque transmitting shaft extends axially from a front end of the front handle section. The rear handle section has a short torque transmitting shaft extending axially from a front end thereof and extending within a central inner bore of the front handle section when the rear handle section is mated with the front handle section. Each of the torque transmitting shafts have a chuck cavity at a free end thereof for receiving a screwdriver bit in close friction fit therein. A bit storing magazine is formed in a rear wall of the front handle section and extends about the handle for storing a plurality of spaced-apart screwdriver bits in friction fit retention therein with an end portion of the bits projecting from the magazine sufficiently for removal by finger engagement. The rear handle section has cavity means to receive projection portions of the bits stored in the magazine when the rear handle section is mated with the front handle section. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which: 
     FIG. 1 is a perspective view showing the dual multi-bit screwdriver of the present invention; 
     FIG. 2 is a side view of the dual multi-bit screwdriver of the present invention showing the two handle sections separated one another whereby to constitute two screwdrivers; 
     FIG. 3 is a sectional side view of the dual multi-bit screwdriver with the handle sections mated with one another; 
     FIG. 4 is an end view showing a modified configuration of the screwdriver bit storage magazine; 
     FIG. 5 is a view similar to FIG. 4 showing the configuration of the screwdriver bit storage magazine of the screwdriver embodiment described herein; 
     FIG. 6 is an enlarged section view showing the friction projection made in the thermoplastic elastomer portion which projects into the cylindrical cavities of the bit storing magazine; 
     FIG. 7 is a side view showing the construction of the front handle section; 
     FIG. 8 is a section view of the handle section along cross-section lines A—A of FIG. 5; 
     FIG. 9 is a side view of the rear handle section; 
     FIG. 10 is an inner end view of the rear handle section shown in FIG. 9; and 
     FIG. 11 s a section view along cross-section lines B—B of FIG.  10 . 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring now to the drawings and more particularly to FIGS. 1 and 2, there is shown generally at  10  the dual multi-bit screwdriver of the present invention. The screwdriver has a handle  11  which is comprised of a front handle section  12  and a rear handle section  13  which are mated in frictional clamping retention with one another. An elongated bit receiving torque transmitting shaft  14  extends axially from the front end  15  of the front handle section  12 . 
     As shown in FIG. 2, when the rear handle section  13  is separated from its clamping friction fit with the front handle section  12 , the rear handle section  13  constitutes a stub screwdriver and it is also provided with a short bit receiving torque transmitting shaft  16  extending axially from the front end  17  thereof. As hereinshown a screwdriver bit  18  is received within a chuck cavity  19  (see FIG. 3) formed at opposed free ends of the shaft  14 . Similarly, as shown in FIG. 3, the front end of the short bit receiving shaft  16  of the rear handle section  13  is provided with a chuck receiving cavity  20  to also receive in close removable fit therein a screwdriver bit  18 . The shafts  14  and  16  are provided with an annular groove  14 ′ and  16 ′, respectively, in their bit receiving chuck cavities  19  and  20 . A spring bias bearing (not shown) is provided in the bits  18  to engage with the grooves  14 ′ and  16 ′, as well known in the art. 
     Both the screw bit receiving shafts  14  and  16  are provided with frictional engagement means in the form of shoulder flanges  21  and  22  for frictional retention in locating slots  21 ′ and  22 ′ provided in the outermost sections of the shaft receiving cylinders  23  and  24  secured in the front handle section  12  and rear handle section  13 , respectively. 
     As shown in FIG. 1, a plurality of flexible projecting fingers  30  extend from a rear circumferential body portion  31  of the front handle section  12  and clampingly frictionally engage with clamping teeth projections  32  formed in the rear handle section  13 , as will be described later. 
     With specific reference to FIGS. 3 and 4 it can be seen that when the screwdriver handle sections  12  and  13  are disconnected from one another it exposes a bit storage magazine which is comprised of a plurality of cylindrical cavities  25  which are formed in the end walls  17  and  27  of both the rear handle section  13  and the front handle section  12 . The cavities in the front handle section have a cross-section adapted to frictionally retain the bits  18  therein. 
     FIG. 5 illustrates that more of these storage cavities  25  can be formed in the end walls of these handle sections wherein to provide multi-bit storage. For example, if eight of these cavities were provided in the end wall and two bits  19  mounted in the chucks  19  and  19 ′ of the bit receiving shaft  14  and with the bits  18  having opposed screw heads, then this would provide eighteen options of screw heads that can be engaged with each of the chuck cavities of both the stub screwdriver formed by the rear handle section  13  and the chuck cavity of the shaft attached to the front handle section  12  thereby giving the screwdriver the possibility of  36  different bit combinations with the use of both screwdrivers formed with the handle sections. 
     Referring now to FIGS. 5 to  8  there will described the construction of the front handle section  12  and its friction clamping fingers. These fingers  31  are recessed from the outer periphery of the front handle section and are provided with a transverse indent  33  at a base thereof above the rear wall  31 . The fingers are located intermediate the cylindrical cavities  25  which form the bit storage magazine. As hereinshown, the cylindrical cavities  25  are of hexagonal cross-section and define six wall sections, one of which is constituted by a pliable thermoplastic elastomer  34  which is injection molded to the rigid plastic body portion  35  of the handle, as shown in FIG.  8 . The pliable thermoplastic elastomer  34  constitutes an outermost one of the six elongated walls  36  of the cavities  25  and also forms an outer handle section  37  which provides improved frictional retention by the hand of a user person to assist and improve torquing the torque transmitting shaft  14  which projects from the front end  15  of the front handle section  12 . The thermoplastic elastomeric wall section  34  is also formed with a projection  34 ′, see FIG. 6, to provide improved frictional retention of a screwdriver bit disposed in the cylindrical cavity  25 . As shown in FIG. 3, these bits project sufficiently from the end wall  27  of the front handle section for finer engagement. 
     Referring now to FIGS. 9 to  11 , there is shown the construction of the rear handle section  13 . As hereinshown it is also provided with pliable thermoplastic elastomeric sections  40  disposed between a plurality of flexible clamping teeth projections  32  spaced apart about the periphery of the rear handle section and dimensioned for flexible clamping engagement with the fingers  31  projecting from the front handle portion  12 . When the handle portions are mated together, the elastomeric sections  40  and  37  are in alignment with one another, and as previously described, this enhances gripping and the application of torque to the screwdriver, combined as shown in FIG. 3 or to the stub screwdriver. 
     As shown in FIG. 10, the stub screwdriver is also provided with cavities  25 ′ dimensioned and aligned with the cavities  25  provided in the front handle section  12 . These cavities merely receive the opposed screw head of the bits stored within the cavities  25  and do not provide frictional engagement thereof. Accordingly, the elastomeric sections  40  are not provided with projections  34 ′ as is the case with the elastomeric portions  34  in the front handle section. 
     In the particular embodiment as shown in FIGS. 5 to  11 , which is the preferred embodiment, there are six of the cylindrical cavities  25  and dimensioned to receive screwdriver bits  18  having opposed screw engaging heads. The elongated torque transmitting shaft  14 , as shown in FIG. 3, is provided with chuck cavities  19  and  19 ′ at opposed ends thereof and also dimensioned to receive screwdriver bits having opposed screw engaging heads. Accordingly, the screwdriver results in a dual multi-bit screwdriver having a capacity of storing eight screwdriver bits having opposed screw engaging heads to adapt to sixteen different types of screw heads with each the elongated screwdriver combined or the stub screwdriver. 
     It is within the ambit of the present invention to cover any obvious modifications of the preferred embodiment described herein, provided such modifications fall within the scope of the appended claims.