Abstract:
A single-bit screwdriver comprising: a housing; a shaft slideably mounted in the housing; the shaft having a locking portion, and the housing having at least two locking mechanism, wherein each locking mechanism engages the locking portion to prevent sliding of the shaft relative to the housing.

Description:
CROSS-REFERENCE 
       [0001]    The present application claims the benefit of U.S. provisional patent application No. 61/222,508, filed Jul. 2, 2009, which is incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The present application relates generally to hand tools. More particularly, the present application relates to a single-bit screwdriver with an extendable and retractable shaft. 
       BACKGROUND 
       [0003]    Conventional screwdrivers have a fixed shaft length. However, the placement and configuration of screws often results in a need for different shaft lengths. Keeping multiple sets of screwdrivers with various shaft lengths increases the cost, weight, and storage required for a set of tools. Moreover, screwdrivers with long shaft lengths can be cumbersome to store and carry. 
         [0004]    There is a need for a screwdriver to have an extendable and retractable shaft in order to be used in at least two configurations. There is a further need for an extendable and retractable screwdriver to be user friendly and retract to a convenient size for maneuvering and storage. 
       SUMMARY 
       [0005]    There is provided a single-bit screwdriver comprising a housing; a shaft slideably mounted in the housing, the shaft having a locking portion, and the housing having at least two locking mechanisms, wherein each locking mechanism engages the locking portion to prevent sliding of the shaft relative to the housing in at least two operable positions. 
         [0006]    In another aspect, there is provided a single-bit screwdriver comprising: a housing; a shaft slideably mounted in the housing; the shaft having a locking portion designed to engage a locking tab at one end of the housing and a locking mechanism at a second end of the housing wherein the locking mechanism and the locking tab engage the locking portion to prevent sliding of the shaft relative to the housing in two operable positions. 
         [0007]    Other aspects and features of the present application will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments in conjunction with the accompanying Figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Embodiments of the present application will now be described, by way of example only, with reference to the attached Figures, wherein: 
           [0009]      FIG. 1  is an exploded perspective view of an embodiment of a single-bit screwdriver; 
           [0010]      FIG. 2  is a cross section view of an exploded perspective view of an embodiment of the single-bit screwdriver; 
           [0011]      FIG. 3  is a cross-section view of an embodiment of the single-bit screwdriver in a retracted position; 
           [0012]      FIG. 4  is a cross-section view of an embodiment of the single-bit screwdriver in an extended position; 
           [0013]      FIG. 5  is cross-section view of an embodiment of the single-bit screwdriver in an extended position with the locking mechanism engaged; 
           [0014]      FIG. 6  is another cross-section of the single-bit screwdriver in the retracted position; 
           [0015]      FIG. 7  is a cross-section of the single-bit screwdriver in the extended position; and 
           [0016]      FIG. 8  is a perspective view of another embodiment of a single-bit screwdriver. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    Generally, there is provided a single-bit screwdriver with an extendable and retractable shaft that can be locked in two or more positions. 
         [0018]      FIGS. 1 and 2  illustrate exploded views of a single-bit screwdriver  10 . The screwdriver  10  comprises a shaft  12 , which is adapted to be slideably held within a housing  18 . A handle portion  22 , shown in  FIGS. 3 to 5 , may cover the housing  18 . The handle portion  22  is preferably overmoulded reducing or eliminating the need for screws or other fasteners to hold the handle portion  22  in place with respect to the final product. The handle portion  22  may also be two or more separate pieces that can be attached to enclose the housing  18 . 
         [0019]    The shaft  12  includes a bit  14  at one end, a fixed extension portion  26  and a slideable extension portion  24 . The end  28  of the slideable extension portion  24  may be enclosed within a locking portion  42  creating a further extension of the shaft  12 . The end  28  of the slideable extension portion  24  may also include features for securing the locking portion  42  to the end. These features may include a groove  30  or aperture  32  incorporated in the end  28  of the slideable extension portion  24  with which the locking portion  42  may connect to securely hold the shaft  12  in place. 
         [0020]    The bit  14  can be any one of a variety of screwdriver bit types, such as slotted, crosshead (Phillips), square, Allen, etc., and integral or otherwise attached to the fixed extension portion  26 . In an alternative embodiment of the single-bit screwdriver, the single-bit retractable screwdriver comprises a bit holder for receiving removable tool bits. In the current embodiment, the slideable extension portion  24  and the housing  18  have hexagonal cross-sections, and are dimensioned to fittingly correspond to each other to allow the slideable portion  24  to smoothly slide through the housing  18  between positions. The hexagonal cross sections reduce or prevent rotation of the shaft  12  relative to the housing  18 , and assist in transmitting the torque generated by rotating the handle  22  to the bit  14 . It will be understood that other cross-sectional shapes for the slideable extension portion  24  and the housing  18  can be used to the same effect. 
         [0021]    In  FIGS. 1 and 2 , some of the internal components of the screwdriver  10  are shown, such as a locking mechanism  16  and the locking portion  42 . The locking mechanism  16  may resemble a button or tab on its exposed portion  17  and its unexposed  19  or bottom portion assists to restrain or retain the shaft  12  in place, allowing the screwdriver to be operable in an extended position. The unexposed portion of the locking mechanism  16  may be designed to engage a recess or slot  50  within the housing  18 , or may be inserted into the housing through an aperture or other design. The locking mechanism  16  may become depressible by a user once it is engaged by the locking portion  42 . 
         [0022]    The locking portion  42  further comprises a plunger  44  and an activator  46 . The plunger  44  may include an angled top surface. The activator  46  may be made of a bias, a spring or a compressible material. In the extended position, the activator  46  presses against the plunger  44 , which in turn engages the locking mechanism  16 . As the locking mechanism  16 , once engaged, is pushed into a depressible position, the plunger  44  becomes locked within the housing  18 , and protrudes from the locking portion  42 . 
         [0023]    Depressing the locking mechanism  16  will compress the activator  46  and push the plunger  44  to a position level with the perimeter of locking portion  42 , thus allowing the shaft  12  to be slid through the housing  18  to another position such as the operable retracted position. In an alternative embodiment, the activator and plunger may be an integrated component, made of compressible material. 
         [0024]    The housing  18  may be connected to a block  34  which has a tapered hollow portion  36  designed to receive the slideable extension portion  24 . The block  34  serves to abut against the locking portion  42  so that the screwdriver may not be dismantled or disassembled even if the locking mechanism  16  were to fail or break. Preferably, the locking portion  42  may also be tapered at the end that abuts the tapered hollow  36  to match the profile of the block  34 . 
         [0025]    The block  34  may further comprise a recessed area  38  designed to engage a corresponding area  48  in the housing  18 . The recessed area  38  may further include a protrusion  40  designed to fit the slot  50  allowing for the internal components to be seated within the screwdriver  10 . It will be understood that for the overmoulding process for the handle portion  22 , a seal is preferred to reduce the chance that the overmoulded material will enter into the housing or screwdriver and hinder use of the screwdriver. The housing  18  may further comprise elongated protrusions  60  or other overmoulding features to set and center the internal components for the overmoulding process. 
         [0026]    The screwdriver  10  may further comprise a second locking mechanism or locking tab  52  at the back end of the housing  18 . The locking tab  52  may include an angled bottom surface or angled protrusion  54  corresponding to the angled surface of the plunger  44 . Alternatively, the locking tab  52  may be a radial surface with sufficient incline or ramp to force the activator to compress when the shaft is slid out from the retracted position. The locking tab  52  frictionally retains the plunger  44 , which allows the shaft to remain in the retracted position. The locking tab  52  may be integrated into the hollow housing  18  or may be a separate piece designed to fit within an aperture  56  in the housing  18 . 
         [0027]    When a user wishes to change the position of screwdriver from the retracted position to the extended position, the user may slide the shaft outwardly, the force of the sliding causes the plunger  44  to overcome the frictional hold of the locking tab  52 . The shaft will slide through the housing  18  until the plunger  44  engages the locking mechanism  16 . 
         [0028]      FIG. 3  illustrates the screwdriver in the operable retracted position. In this position the plunger  44  is frictionally held in place by the locking tab  52 . The activator  46  is held in a compressed form within the housing  18 . 
         [0029]      FIG. 4  illustrates the screwdriver in an extended position. In reaching the extended position, the slideable extension portion  24  may be slid through the housing  18  until the locking portion  42  engages the locking mechanism  16 . 
         [0030]    Once the locking mechanism  16  is engaged by the locking portion  42 , the engaged locking mechanism  16  will become depressible by a user. The user may depress the locking mechanism  16 , unlocking the locking portion  42 , as shown in  FIG. 5 . Once the locking mechanism  16  is depressed, the locking portion  42  will become disengaged and the user may then slide the shaft to the operable retracted position or any intermediate position. 
         [0031]      FIG. 6  shows a cross section of the screwdriver in the operable retracted position prior to being fitted with the handle portion.  FIG. 7  illustrates a cross section of the screwdriver in the operable extended position wherein the fixed extension portion  26  comprises a hexagonal cross section. From these cross-sectional figures, the locking tab  52  and locking mechanism  16  are each viewable in their locked and unlocked position.  FIG. 6  illustrates the frictional lock the locking tab  52  may exert on the plunger  44 .  FIG. 7  shows the locking tab disengaged and the locking mechanism  16  engaged through the expansion of the activator  46  within the plunger  44 . 
         [0032]      FIG. 8  further illustrates an alternative embodiment of the screwdriver with multiple locking positions. In this embodiment, the housing  18  may be equipped with a plurality locking mechanisms  16  along one side of the housing. Once the shaft travels through the housing, the locking portion  42  may engage each of the plurality of locking mechanisms  16 . Once the plunger of the locking portion engages a locking mechanism  16 , the locking mechanism  16  will become depressible to disengage the plunger and locking portion. When the user depresses the locking mechanism  16 , the user can select whether to slide the shaft outward to a further extended position or to retract the shaft to a shorter retracted position. It will be understood the number of locking mechanisms and therefore number of operable positions available may depend on the length of the shaft and the length of the housing. To ensure a comfortable grip of the handle portion, it may be preferred to have only one extended and one retracted operable position. 
         [0033]    The above-described embodiments are intended to be examples only. Alterations, modifications and variations can be effected to the particular embodiments by those of skill in the art without departing from the scope of the invention, which is defined solely by the claims appended hereto.