Abstract:
An apparatus for telescopically extending the shaft length of a tool including a handle with a circular or noncircular hollow core shaft with at least one longitudinal extension channel, a circular or noncircular hollow shank wherein one end has an internally threaded drive ring with at least one tab for insertion into an extension channel, and the second end has a head assembly to receive various tool fittings where an externally threaded adjusting rod extends into the hollow shank and is engaged in the threaded drive ring and is operated by a rotatable adjusting knob is attached to the adjusting rod, and a lock assembly is used to selectively eliminate rotation of the knob; the lock assembly comprises a pair of facing spline faces which engagingly prevent rotation of the knob.

Description:
[0001]    The present application claims priority from provisional patent application No. 60/183,878 entitled TELESCOPING TOOL HANDLE, filed Feb. 22, 2000. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    This invention relates generally to the field of hand tools, and more particularly to an apparatus for telescopically extending the shaft length of a tool used for tuning a fastener or the like while protecting the critical mechanisms for extending the tool shaft by moving the mechanism inside the handle. An additional feature of the invention is adaptation to use multiple replaceable tool ends for performance of multiple tasks.  
           [0003]    All too often, the problem is found in the field, when a user must access a fastener that is in difficult location. Traditionally, a user must have available for ready access tools of multiple lengths. Short tools must be available for working in restricted spaces, long tools must be available for reaching the tool into a restricted space or moving the user away from the fastener.  
           [0004]    Short or “stubby” tools are useful and often necessary for working in a confined space, but, suffer from an additional shortcoming of being small and therefore having small handles that are frequently difficult to grasp and apply sufficient torque to the fastener. While longer tools do not suffer the same shortcoming&#39;s as short tools they have there separate problems, including being large and therefore difficult to store.  
           [0005]    As a result, most conventional screwdrivers and tool handles are of medium length and perform adequately in most circumstances, but, cannot be used in all circumstances necessitating the user owning and using multiple drivers as the task requires.  
         SUMMARY OF THE INVENTION  
         [0006]    The tool industry over the years has innovated new and useful tool designs to meet specific industry requirements for additional tool utility. Tools of multiple functionality have entered the tool industry, and have found valued place in many tool boxes. Telescoping shaft length tools can improve work efficiency by reducing the number of tools of that a user must have available for use. Thus a user can perform more work in a given time.  
           [0007]    The invention is to provides a telescoping shank for telescopically extending the length of a screw driver, socket end, or a wrench; making the tool more versatile than existing tools having a smooth, non-threaded shank, which is easy and relatively inexpensive to manufacture. The telescoping mechanisms is housed internally in the tool handle, providing protection to these critical mechanisms, and making the tool more dependable, and of greater utility.  
           [0008]    The telescoping of the tool is controlled by a lockable adjustment knob located on the end of a handle so that a user can easily alter the length regardless of the location of the tool. The telescoping shank is nonremovable and can be integrated into a handle minimizing the size of the tool while protecting the adjustment mechanism.  
           [0009]    An apparatus for telescopically extending the shaft length of a tool, comprising: a handle with a circular or noncircular hollow core shaft with at least one longitudinal channel in combination with a hollow shank with circular or noncircular cross section, with integral, internally threaded drive ring on one end. The drive ring has at least one associated tab for insertion into the longitudinal channel. The second shank end has a head assembly to receive screw driver, socket, or wrench tool fittings. Circular shaft and shank cross sections are associated with the screw driver or socket configuration, in addition, a noncircular or elliptical cross section is associated with a wrench configuration. An externally threaded adjusting rod engages the threaded drive ring, and extends into the hollow shank. A rotatable adjusting knob is attached to the adjusting rod. A lock mechanism which is integral to the adjusting knob attached to the handle which is used to selectively eliminate rotation of the knob. The lock assembly comprises a first friction washer attached to the knob and a second friction washer attached to the handle wherein the washers engage each other to prevent rotation of the knob. Alternatively, the lock assembly comprises a first splined portion attached to the knob and a second splined portion attached to the handle wherein the portions engage each other. A spring, and spring retainer system is attached to the adjusting rod to provide engaging force on the splined portions. A key is attached to the adjusting rod as a means of transferring rotational force between the adjusting knob and the adjusting rod. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is a perspective view showing the first embodiment of a telescoping tool according to the present invention; showing a partial cut away internal view of the drive mechanism.  
         [0011]    [0011]FIG. 2 is a longitudinal sectional view taken along the plane of line  2 - 2  of FIG. 1  
         [0012]    [0012]FIG. 3 is an exploded view of the telescoping tool handle showing an alternate embodiment of the locking mechanism.  
         [0013]    [0013]FIG. 4 is a partial cut away view of the first embodiment of the telescoping tool handle showing the adjustment mechanism and the locking mechanism.  
         [0014]    [0014]FIG. 5 is a longitudinal cross sectional view of a second embodiment of the telescoping tool handle showing the alternate shank construction.  
         [0015]    [0015]FIG. 6 is detailed partial view of the second embodiment of the telescoping tool handle showing a crow-foot wrench attached.  
         [0016]    [0016]FIG. 7 is a partial exploded view of the second embodiment of the telescoping tool handle showing the alternate locking mechanism.  
         [0017]    [0017]FIG. 8 is an isometric view of an alternate embodiment of the telescoping tool handle showing the transparent adjustment window. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]    Referring first to FIG. 1, which shows a first embodiment of the telescoping shafted tool  10 . The first embodiment is generally in the form of a screwdriver having a handle  12  and a shaft  14  adapted to receive a conventional replaceable tip  16 . The tool  10  additionally has an adjustment knob  18  for extending or retracting the shaft  14  of the tool  10 . The extension mechanism  20  of the tool  10  is contained within the handle  12  and attached to both the adjustment knob  18  and the shaft  14 .  
         [0019]    The shaft  14  is a hollow tube that, while being shown as circular in cross section, need not be circular and is formed having an adapter  22  on the distal end to receive a replaceable tip  16 . A standard replaceable tip  16  is formed from a ¼ inch hexagonal rod and has a point on the one end for mating with a screw head or nut. The point may be a flat blade, phillips, Torx,® Robertson,® or a nut driver having a female hex for accessing a standard hex nut. It is preferred, therefore that the internal hollow  24  of the shaft  14  be in the form of a regular ¼ inch hexagon to utilize standard replaceable tips  16 . Standard replaceable tips  16  are a fungible item well known in the art and readily available in the marketplace.  
         [0020]    The shaft further can have a means for retaining the replaceable tips  16  contained within the hollow  24 . The means for retaining the replacement tips  16  are well known in the art and can include a magnet for magnetically holding the tips  16  and various mechanical mechanisms such as deformable clips or deformable rings contained within the hollow portion  24  of the shaft  14 . Alternately, the retaining means may be may be constructed as part of the replaceable tip  16 .  
         [0021]    The shaft  14  may be constructed from any one of a number of materials, including, metals or polymers having the necessary properties of workability, strength, and durability. A preferred material is a ferrous alloy.  
         [0022]    The proximal end  26  of the shaft carries the drive mechanism  28  which is a hollow plug having an internal threaded hole  30  and a pair of extending drive tabs  32  which mate with the handle. The drive mechanism  28  may be constructed from any suitable material such as a metal, or a hard polymer and is preferably constructed from a ferrous alloy having suitable properties, which include, strength, durability and workability. Additionally, the drive mechanism must slide within the channels  36  of the handle  12  without excessively wear or galling the channels  36 . The drive mechanism  28  may be constructed integral with the shaft  14  or may be fabricated separately and attached using any suitable means of attachment, such as, welding, fusing, discrete fasteners, or adhesives.  
         [0023]    The handle  12  is constructed, generally, as an elongate cylinder a length and diameter sufficient to contain the drive mechanism  28  and the extension mechanism  20 . Additionally, the handle is sized to be comfortable gripped by a user. The handle as shown in FIG. 1 has an embossed external surface  34  to cooperate with the user and provide an enhanced grip. It is understood that the handle  12  may be formed in other suitable shapes, such as, having longitudinal external flutes, or being non-circular to enhance the gripability.  
         [0024]    The handle  12  is at least partially hollow to contain the drive mechanism  28  and the extension mechanism  20 . The handle further has a pair of internal channels  36  for receiving the drive tabs  32 . While a pair of drive tabs  32  and channels  36  is preferred, it is understood that at least one is required. The internal channels  36  extend from the proximal end of the handle  12 , adjacent the adjustment knob  18  longitudinally to near the distal end of the handle  12 . The internal channels  36  limit the longitudinal movement of the drive mechanism  28 , and therefore the extension of the shaft  14 . The channels  36  extend from the proximal end of the handle  12  essentially the length of the hollow portion of the handle limiting the longitudinal extension of the drive mechanism  38 . A plug  37  may be inserted into the hollow in the proximal end of the handle  12  to retain the drive mechanism  28  and limit the contraction of the drive mechanism  38 .  
         [0025]    The handle  12  may be constructed from any number of suitable materials, such as, hard polymers, metals, or hard fine grained wood having the necessary properties of strength, durability, and workability. When the handle is constructed from a polymer, the polymer may be opaque, translucent, or transparent. In some of the embodiments, as described below, it is preferred that the polymer be transparent or translucent. Additionally, the handle  12  or at least the portion of the handle forming the internal channels  36 , must have sufficient durability to allow the repetitive sliding of the drive tabs  32  therealong. Preferably, the drive tabs  32  and the internal channels  36  will be self-lubricating to allow the sliding of the drive tabs  32  without excessive wear. Alternately, a separate lubricant may be used to reduce wear between the drive tabs  32  and the channels  36 .  
         [0026]    The adjustment knob  18  is attached to the proximal end of the handle  12 . The adjustment knob  18  may be of any suitable shape such as round, oval, or “T” shaped and may be sized having either larger or smaller diameter than the handle  12 . The size of the adjustment knob  18  may have a larger diameter to enhance the ease of gripping by the user, the maximum size is limited only that as the size grows larger, the ability to use the telescoping extension tool  10  in a restricted space becomes compromised. Similarly, the diameter of the adjustment knob  19  may be smaller than the diameter of the handle  12 , the minimum diameter of the of the adjustment knob  18  is only limited by the dexterity of the user, that is, as the diameter of the adjustment knob  18  is reduced, it will become difficult for a user to grasp and turn, ultimately, becoming so small that another tool becomes necessary to grasp the adjustment knob  18 .  
         [0027]    The adjustment knob  18  may be constructed from any suitable material, such as, metal, polymers, or hard wood. It is preferred that he adjustment knob  18  be constructed from the same material as the handle  12 . The periphery of the adjustment knob  18  may be smooth or have an embossed pattern or a polygonal or otherwise irregular shape to enhance the ability of the user to grip and turn the adjustment knob  18 . The adjustment knob  18  may be attached to the adjustment rod  38  using any suitable method of attachment such as press fit, welding or fusion, or mechanical fasteners. One preferred example of attachment includes the formation of internal grooves on the periphery of a center hole in the adjustment knob  18  and forming mating external ridges on the outer surface of the adjustment rod  38 . Alternately, at least one key  35  may be used to retain the adjustment knob  18  and prevent rotation upon the adjustment rod  38 . When keys  35  is used, keyways must be milled in the adjustment rod  38  and matching keyways in the in adjustment knob  18 .  
         [0028]    The adjustment knob  18  has an adjustment rod  38  extending longitudinally therefrom. The adjustment rod  38  extends from the adjustment knob  18  through the internally threaded hole  30  or the drive mechanism  28  and is externally threaded to engage the internal threads of the threaded hole  30 . The threads  40  are preferably of quite coarse pitch such as one to three threads per inch so that very few turns of the adjustment knob  18  will move the extension mechanism  20  through the entire range of motion. The adjustment rod  38  may be constructed from any suitable material having sufficient strength and durability. Suitable materials would include hard polymers and metals. Preferably, the adjustment rod  38  is constructed from an iron alloy the is suitable to engage the threaded hole  30  and sufficiently durable so that there is a minimum of wear between the parts.  
         [0029]    The locking mechanism  42  as shown in FIG. 4, consists of a pair of friction washers  44 . 1 ,  44 . 2  which when urged together restrict or prevent the rotation of the adjustment knob  18  with respect to the handle  12 . The locking mechanism further  42  further includes a lock knob  46  and a thrust washer  48 . The lock knob  46  is threadedly attached to the proximal end of the drive rod  3   8  using the lock knob  46 . A thrust face  50  is an expanded diameter portion formed on the adjustment rod  38  for engaging the distal face of the plug  37  so that when the lock knob  46  is tightened, the adjustment knob  18 , the locking washers  44 , the plug  37  and the adjustment rod  38  are drawn together and prevented from rotating with respect to each other.  
         [0030]    While it is not necessary, it is preferred that a protector cap  52  be included to cover the locking knob  46 . The protector cap  52  is used to protect the threads of the locking knob  46  from environmental debris or abuse from the user. The protector cap  52  may be fabricated from any suitable material, such as metal, polymers, or wood. It is preferred that the protector cap be formed from the same polymer as the handle  12  and be molded integral with the handle  12 .  
         [0031]    In another embodiment of the invention  110  as shown in FIG. 3, shows an alternate embodiment of the shaft  114  and its assembly and the preferred embodiment of the locking mechanism  142  adapted to accept replaceable tips  116  designed to grip and thereby turn standard hexagonal nuts.  
         [0032]    While the drawings show a round shaft  114 , in this embodiment, the shaft  114  may be and is preferably polygonal square in cross section. When a non-round shaft  114  is used, drive mechanism can be modified to obviate the drive tabs  132  as the shaft  114  can be fitted in an appropriately shaped hole to receive the limited torque loads of this embodiment.  
         [0033]    In this embodiment, the shaft  1   14  has been modified by changing the cross sectional shape to a rectangular tube, or a “C” shaped channel, as shown more clearly in FIG. 6. The replaceable tip, commonly called a crow foot wrench  117  has been placed into the shaft  114 . The crow foot wrenches  117  are designed to be placed on the end of a square drive wrench or extension as evinced by the square recess  119  formed therein, and be used to access standard sized hexagonal nuts in otherwise inaccessible restricted spaces. It has been discovered that the crow foot wenches can be gripped by the outer edges and used as a replaceable tip on a linear wrench, functioning much like a variable length open end wrench.  
         [0034]    The shaft  114  is rectangular in shape is sized to allow a user to apply a pushing or pulling force to the handle  112  to rotate a hex nut held in the crow foot wrench  117 . This requires the shaft to be resilient yet essentially non-bendable along its length. The shaft  114  may be fabricated from numerous material having the desired properties, such as various metals, polymers, or glass filled polymers. It is preferred that the shaft be constructed from a steel alloy.  
         [0035]    The shaft  115  has an interior opening or channel  115  sized to receive a crow foot wrench  117 , as shown in FIG. 6. The fit of the crow foot wrench  117  to the channel should be a close or interference fit so that the crow foot wrench is retained during use, but, can be readily removed when another replaceable tip  116  is needed.  
         [0036]    The preferred embodiment of the locking mechanism  142 , as shown in the exploded view of FIG. 3 consists of a pair of mating splined faces  144 , the first splined face  144 . 1  is formed on the proximal end of the handle  112  and the second splined face  144 . 2  is formed on the distal end of the adjustment knob  118 . The splined faces  144  are shown as having a multiplicity of approximating a “V” shaped teeth  145  in FIG. 2 and approximately gear shaped teeth  145  in FIG. 3. This merely shows two of the many shapes the teeth  145  of the splined faces  144  may have. The teeth may also be shaped as intermeshing rectangles or intermeshing curved surfaces. In one embodiment, the teeth  145  of the one splined face  144 . 1  are approximately parabolic is shape and the teeth  145  of the other splined face  144 . 2  are shaped as a mating negative parabola. It is preferred that at least one of splined faces  144  have somewhat pointed teeth. The shape of the teeth  145  can be varied, and by having at least one of the splined faces  144  having pointed teeth  145 , the adjustment knob  118  becomes self-locking. That is, for example, using rectangular shaped teeth, when the adjustment knob  118  is urged away from the handle  112  to disengage the splined faces  144  so that the adjustment knob  118  may be rotated with respect to the handle  112  to alter the extension of the shaft  114  and released, it is likely that the splined faces  144  will not mesh and must be manually turned, slightly, to allow the splined faces  144  to engage. While this is a minor inconvenience, it can be avoided by the use of pointed teeth  145 . With pointed teeth  145 , there is a minimal, if any, flat surface of splined faces  144  for the teeth  145  to rest upon, and upon release, the adjustment knob  118  will be drawn toward the handle  112  by the tension of the adjustment  
         [0037]    The quantity of teeth  145  on each of the splined faces  144  much correspond and the actual number may vary in different applications. The number of teeth  145  defines the number of increments the adjustment knob  118  can have per revolution. The selection of the number of teeth  145 , is at best, a compromise between a an infinite number of teeth  145  which would allow extension of the shaft  114  to an infinite number of positions and a small number of teeth  145  which would only allow the shaft to be at a small number of extension lengths. It is preferred that there be a substantial number of teeth  145  to allow the extension of the shaft  114  to be varied in small increments. The teeth  145  also must be sufficiently large to have sufficient strength to withstand the repeated torque placed upon the teeth  145  in use.  
         [0038]    The adjustment knob  118  has a center hole and an enlarged recess  143  extending inwardly from the proximal end. The adjustment knob  118  fits over the proximal end of the adjustment rod  138  and is retained thereat by the adjustment rod spring  146  and spring retainer  148 . The recess  143  is then covered with a cap  150  to prevent the intrusion of debris. The adjustment rod spring  146  may be a conventional coiled metallic spring, a metallic spring of other shape, or merely a sleeve of compressible resilient material. The spring retainer  148  may be any suitable means for retaining the rod spring  146  in the desired location. The preferred spring retainer  148  is a “c” clip fitted into a circular recess near the proximal end of the adjustment rod  138 .  
         [0039]    In another embodiment of the invention  10 , as shown in FIG. 8, the handle  12  has an elongate transparent window  54  on the periphery of the handle and a graduated extension scale  58  visible through the transparent window  56 . A pointer  60  may be formed on one part of the extension mechanism  20  and a graduated scale  58  on an adjacent portion of the handle  12 . Alternately, the pointer may be formed on the handle  12  and the graduated scale  58  formed on the plug  37 .  
         [0040]    The use of the tool  10  will be described, first, with respect to the screw driver embodiment as shown in FIG. 1 with the preferred embodiment of the locking mechanism as shown in FIG. 3. The user first selects the tool  10  from the place of storage, and if necessary, selects and inserts the proper replaceable tip  16 . In the work area the user will adjust the length or extension of the shaft  114  by urging the adjustment knob  118  away from the handle  112  and rotating the adjustment knob  118  with respect to the handle  112 . When the desired length of the tool  10  is achieved, the user released the adjustment knob  118  and allows the adjustment knob to seat with the splined faces  144  engaged. The user may now fit the replaceable tip  16  into the recess of the selected fastener and turn the fastener. Should the selected length be incorrect, the user need only again disengage the teeth  145  of the splined faces  144  and again rotate the adjustment knob  118  to obtain the correct length. Additionally, for storage, the shaft  1   14  may be fully retracted to save space.  
         [0041]    When a tool having the first embodiment of the locking mechanism is used, to change the extension of the tool  10 , the user must first remove the protector cap  52  to access the locking knob  46 , the locking knob  46  is loosened which allows the adjustment knob  18  to be turned with respect to the handle  12  allowing the user to select the extension of the shaft  14  and therefore the length of the tool. When the chosen length is achieved, the user may then tighten the locking knob  46  to fix the tool  10  in its selected length for use.  
         [0042]    With the use of a tool  10  having the second embodiment of the shaft  114 , the length selecting process is as described above. The only difference is that the replaceable bit  116  selected is a crow foot wrench  117 . The use of the tool  110  is also different in that the tool  110  is moved laterally by the user to rotate the fastener held in the replaceable bit  116  as contrasted with the tool  10  being rotated about its longitudinal axis in the previous embodiments.  
         [0043]    Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize changes may be made in form and detail without departing from the spirit and scope of the invention.