Abstract:
A battery-operated screwdriver has a housing with a handle, a rechargeable battery, charge contacts for charging the battery on a charger shell having at least one detachably mounted bit holder for storing tool inserts of the battery-operated screwdriver in captive fashion, so that the battery-operated screwdriver is placeable on the charger shell and a charging mode is produced automatically, and a charger shell for a battery-operated screwdriver has at least one detachable mountable bit holder configured to receive a plurality of bits which in operation are insertable in communication with the battery-operated screwdriver.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of priority of U.S. patent application Ser. No. 10/573,627 filed on Mar. 26, 2008 under 35 USC 119(e). The subject matter of the aforesaid U.S. patent application is further explicitly incorporated herein by reference thereto. 
         [0002]    The invention described and claimed hereinbelow is also described in German Patent Application DE 10 2004 038 788.5 filed on Aug. 9, 2004. This German Patent Application, whose subject matter is incorporated here by reference, provides the basis for a claim of priority of invention under 35 U.S.C. 119(a)-(d). 
     
    
     BACKGROUND OF THE INVENTION 
       [0003]    The present invention relates to a battery-operated screwdriver, and also to a charger shell for a battery-operated screwdriver. 
         [0004]    Battery-operated screwdrivers are already available in the 2.4V to 3.6V power class, as known for instance from European Patent Disclosure EP 1 066 930. They usually have NiCd cells as energy-storing means, an ON/OFF switch with a short switch button, and without continuously variable speed governing they have both a switch for switchover from counterclockwise to clockwise operation, a gear, in particular a planetary gear, that steps the motor rpm down, and a motor with a standard diameter of 27.5 mm. There are rodlike and pistol-shaped versions as well as versions with a grip whose angle can be adjusted. For charging, these devices are either connected to a charger via a plug—in the manner of a cell phone or electric shaver—or are connected to contacts via a mount into which the device is placed. The mounts can be secured to a wall, for instance, to make handling for charging simpler. 
         [0005]    For that purpose, the charging mode must be brought about for both the charger and the electrical connection, but this does not happen automatically after every use. As a result, the device is often not ready for use precisely when it is needed, and the familiar memory effect for conventional NiCd batteries is another disadvantage. After a certain amount of time of not outputting power, NiCd batteries discharge, and so battery-operated screwdrivers equipped with them discharge partially after a short time even when not used. If they are put in the charging mode when they are partially discharged, then after charging, because of the memory effect, only the difference from the newly charged quantity—and hence reduced power—is available. 
         [0006]    Another disadvantage of the known battery-operated screwdrivers is the limited availability of screwdriver bits and various tool inserts. 
       SUMMARY OF THE INVENTION 
       [0007]    Accordingly, it is an object of the present invention to provide a battery-operated screwdriver, and also a charger shell for a battery-operated screwdriver, which eliminated the disadvantages of the prior art. 
         [0008]    In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated in a battery-operated screwdriver, comprising a housing with a handle, a rechargeable battery, charge contacts for charging the battery on a charger shell having at least one detachably mounted bit holder for storing tool inserts of the battery-operated screwdriver in captive fashion, so that the battery-operated screwdriver is placeable on the charger shell and a charging mode is produced automatically. 
         [0009]    Another feature of the present invention resides in a charger shell for a battery-operated screwdriver, comprising at least one detachable mountable bit holder configured to receive a plurality of bits which in operation are insertable in communication with the battery-operated screwdriver. 
         [0010]    A further feature of the present invention resides in a charger shell for a battery-operated screwdriver, comprising at least one detachably mountable bit holder configured to receive a plurality of bits in which an operation are insertable in communication with a battery-operated screwdriver that has a housing with a handle, a rechargeable battery, and charge contact tongues for charging the battery on the charger shell, the charger shell being configured so that when the battery-operated screwdriver is placed on the charger shell the charging mode is produced automatically. 
         [0011]    When the battery-operated screwdriver is placed on the charger shell the charging mode is produced automatically and it has the advantage that the battery-operated screwdriver can always be picked up quickly and securely at the same place, with its full available charged capacity, it can be manufactured economically, and is extremely lightweight and handy. 
         [0012]    Since there is almost no self-discharging in a lithium ion cell, the battery-operated screwdriver is fully ready for use even after long periods when it is not in use, and in such periods the battery-operated screwdriver can rest for an arbitrarily long time on the charger shell in the charging mode, The charger shell can be placed, standing securely, on a flat storage shelf and need not be secured or firmly held when the battery-operated screwdriver is being removed. As a result, it can always be removed quickly with only one hand; no plug has to be unplugged and no mount has to be removed. Moreover, it is automatically assured at all times that the battery-operated screwdriver is charged. 
         [0013]    The charge contact tongues soldered to the circuit board protrude through openings in the lower end of the handle and in the charging position are contacted by counterpart contacts of the charger shell; no additional cords or coupling plugs have to be actuated. 
         [0014]    Depending on the direction of rotation of the motor, either a green light-emitting diode or LED—acting as a directional arrow pointing forward—or a red LED—as a directional arrow pointing to the rear—soldered to the circuit board lights up. These LEDs are visible through openings in the housing, which are covered by means of a transparent plastic part acting as a window. A further LED with a rectangular frame, located between them, serves as a charge control light or charge status indicator. 
         [0015]    Because only a single long, slender lithium ion (Li ion) cell fixedly built into the handle of the battery-operated screwdriver is used, instead of a plurality of ⅘ sub-C nickel-cadmium cells as a rechargeable battery, an especially small circumference of the grip can be achieved. 
         [0016]    Two relatively large, hard spiral springs keep the ON/OFF button prestressed in its off position, and by fast opening and closing of the contacts, given their increasingly high impedance over the service life, prevent their becoming fused to the contact plate. 
         [0017]    The long ON/OFF button has a short actuation stroke, and as a result, it is especially easily actuatable at any arbitrary location in a way that switches on reliably. As a result—regardless of the actuation position—only slight operator control forces are necessary, and the device can be switched on comfortably in virtually any position of the user&#39;s hand. To improve the guidance of the ON/OFF button relative to the housing, the ON/OFF button has two lateral guide tongues on its inside, which are slidingly supported in a braced fashion in the housing. 
         [0018]    A further volumetric reduction of the battery-operated screwdriver is achieved by means of a compact construction of the gear and gearbox; the gear, as a planetary gear, is merely placed in the cylindrical gearbox and is prevented from falling out by an axial securing plate, and the gearbox itself, with internal toothing, also acts as a sun wheel. 
         [0019]    Because the motor housing is composed of half shells slit in the middle, which embrace the gearbox from both sides in the manner of tongs with radially inward-protruding support tongues and keep it centered in the installed position, the gearbox can be connected precisely and securely to the motor housing without separate fastening elements such as screws or overlooking elements. 
         [0020]    A further reduction in the weight and volume of the battery-operated screwdriver is achieved by dispensing with a chuck; by means of a hexagonal socket in the power takeoff shaft—fitting corresponding screwdriver or drilling bits with a hexagonal shaft—these tools can be changed quickly and simply. 
         [0021]    The ON/OFF button and the switch for reducing the direction of rotation are designed such that on the one hand, when the ON/OFF button is pressed, the switch for reducing the direction of rotation is blocked and cannot be moved, and on the other, the ON/OFF button is blocked and cannot be pressed into the ON position when the switch for reducing the direction of rotation is in the middle position, which is the recommended transport position. 
         [0022]    The gearbox, the circuit board with the battery, motor, LEDs, and electrical elements, as well as the switch button with contact plate and springs, and the transparent plastic part are placed in a first half shell; the second half shell is placed over it and closed with only four identical screws and is thus completely mounted and makes for a very economical embodiment. 
         [0023]    The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIG. 1  is a side view of the partly opened battery-operated screwdriver; 
           [0025]      FIG. 2  is a front elevation view of the battery-operated screwdriver; 
           [0026]      FIG. 3  is a side view of the battery-operated screwdriver, positioned in a charger shell; 
           [0027]      FIG. 4  is an enlarged detail of the grip region of  FIG. 1 ; 
           [0028]      FIG. 5  is a top view on the charger shell with the battery-operated screwdriver in the charging position; 
           [0029]      FIG. 6  is a view from behind of the charger shell with the battery-operated screwdriver of  FIG. 5 ; 
           [0030]      FIG. 7  is a side view of the charger shell with the battery-operated screwdriver of  FIG. 5 , with a separate bit holder; and 
           [0031]      FIG. 8  is a three-dimensional view of a variant of the charger shell seen from above. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0032]      FIG. 1  shows a pistol-like battery-operated screwdriver  10  with a motor housing  12  aligned with the screwing direction and with a handle  14  at an angle from the housing. The motor housing  12  with the handle  14  is formed of two half shells  16 ,  17 , which can be put together, braced tightly against one another, in a central plane  15 . To that end, four screws extend through bores in the one half shell  17  into four screw domes  19  in the other half shell  16  and hold the two firmly against one another. 
         [0033]    An ON/OFF button  26  extends over the internal length of the handle  14 , for actuating a switch, not identified by reference numeral. Because of its particular length, the ON/OFF button  26  makes it easy to switch the battery-operated screwdriver  10  on and off, even in positions in which it is difficult to hold the battery-operated screwdriver. On its long sides, it is provided with support tongues  27  that enter the handle  14  laterally and form a secure guide on corresponding counterpart faces of the half shells  16 ,  17  and enable a precise, play-free back-and-forth motion. 
         [0034]    The ON/OFF button  26  is braced elastically on the handle  14  via two hard compression springs  28 ,  30 , so that after the battery-operated screwdriver is switched on, the springs  28 ,  30  automatically return the ON/OFF button  26 , when it is let go, to its off position and stop the motion of the motor. The actuation stroke is limited by stops, not identified by reference numeral, and with a length of 1 to 4 mm is very short and user-friendly. 
         [0035]    For the entry of the ON/OFF button  26  into the motor housing  12 , a corresponding opening  29 , half of it located in each of the half shells  16 ,  17 , is provided which closely embraces the ON/OFF button  26  and guides it in shaftlike fashion. The ON/OFF button  26 , on its face end toward the handle  14 , has one longitudinally protruding tongue each at the top and bottom; these tongues protrude past the opening  29  and are braced from inside on its edge and keep the ON/OFF button  26  braced thereon in the off position and prevent its coming loose from the housing  12 . 
         [0036]    The circuit board  36 , in its lower region, has two symmetrical symmetrically arranged charge contact tongues  37 , which emerge from the plane of the circuit board  36  at a right angle and then each form large bearing faces bent outward at an angle on the end. These faces penetrate each half shell  16 ,  17  symmetrically to the center plane  15  in the lower end of the handle  14 . At each place where they pass through it, they are embedded in “countersunk” fashion in a respective indentation inside the contour of the handle and are accessible for the outward-protruding charge contacts  23  of the charger shell  22 , which they fit over in the charging state when resting on the charger shell  22  and are braced, securely contacted, because of their resilient arrangement. 
         [0037]    The circuit board  36  also, approximately centrally and flat and near the surface, has interference resistors and capacitors, not identified by reference numerals, and in the upper region it has the slider switch  38  as well as two LEDs  57 ,  58  on the upper end for visually indicating the direction of rotation. 
         [0038]    The circuit board  36  is located with its long side parallel to the handle  14  and with its short side crosswise to the center plane  15  and is clamped without play in groovelike recesses, not identified by reference numeral, in the two half shells  16 ,  17  in such a way that it is braced from the inside against the half shells  16 ,  17  and thus forms a reinforcing rib in the handle  14 . Parallel to the circuit board  36 , a lithium ion cell with its known advantages as a battery  40  is placed in the handle  14 ; in the installed state, it is embraced in tonglike fashion by the two half shells  16 ,  17  and positionally secured and is thus integrated into the strength structure of the housing  12 . The battery  40  has a contact plate  42 ,  43 , one at the top and one at the bottom, acting as a soldering lug and wired to the circuit board  36 . 
         [0039]    Above the ON/OFF button  26 —in the nip between the angled handle  14  and the motor housing  12 —a slider sensor  39  is located transversely to the center plane  15  of the motor housing  12  and can be displaced back and forth through lateral openings, not identified by reference numeral, in the half shells  16 ,  17 . In forklike fashion, with an approximately central recess identified by reference numeral, the slider sensor  39  embraces a sliding device  41  of a boxlike slider switch  38  that is fixed in the upper region of the circuit board  36 . The sliding device  41 , placed on the slider switch  38 , is adjustable via the slider sensor  39  into the extreme left and extreme right side positions and into a middle position. 
         [0040]    A direct current motor  46  in the front region of the motor housing  12  is embraced in tonglike fashion by the half shells  16 ,  17  after they have been installed and is held in its working position without play, aligned parallel with the gearbox  18  placed in the motor housing  12 . The motor  46  has one rear and one front steplike motor collar  48 ,  49 , from which the rear and front ends of the motor shaft  45  emerge. Via its front and rear motor collars  48 ,  49 , the motor  46  is supported, centered in braced fashion, in corresponding bearing-block-like ribs of the half shells  16 ,  17 . The front end  47  of the motor shaft  45  is provided with a flat face or a dihedron, in particular reshaped, and in the installed position with this face or faces reaches into a correspondingly flattened recess of an input pinion  66  of the gear  65 , designed as a planetary gear, that is located in the gearbox  18 . A force-locking coupling with a coarse dimensional tolerance and ease of installation is thus created, and the motor  46  with the gear  65  and the gearbox  18  can easily be put together and placed, in put-together form, into one of the half shells  16 ,  17  for further assembly. 
         [0041]    On the face end, the two half shells  16 ,  17  embrace a gearbox  18 , mounted as a separate cylindrical structural unit, in tonglike and form-locking fashion and firmly hold it without play. The gearbox, in two axial, tonguelike, partly cylindrical extensions  60 , extending toward the motor housing  12 , has an annular housing groove  54 , which is defined by an annular bead  55 . The annular bead  55  engages a fitting counterpart annular bead  56  on the inside of the face end of the half shells  16 ,  17  of the motor housing  12 ; counterpart annular beads  53  that fit them on the half shells  16 ,  17  engage the annular housing groove  54  of the gearbox  18  in form-locking fashion. 
         [0042]    Counterpart extensions  61 , angled transversely to the longitudinal direction of the motor housing  12 , reach without play into the two asymmetrical recesses between the two extensions  60  of the gearbox  18  and at the same time, in the manner of a bearing block, brace the motor collar  58  of the motor  46  in centering fashion, so that the motor collar is likewise integrated into the strength structure of the motor housing  12 . No special fastening elements such as screws or the like are then needed. This makes the assembly easier, with a reduced number of individual parts. 
         [0043]    At the top, the motor housing  12  has a transparent window  59  placed in it, which extends longitudinally in the parting planes and is split in the middle. Through three openings in the half shells  16 ,  17 , it provides a view to one blue and one red LED  57 ,  58 , each associated with one direction of rotation of the motor shaft  45  and being aligned with it, as well as one charge control light located between the two LEDs. 
         [0044]    A power takeoff spindle  20 , designed on its face end as a hexagonal socket  21  for receiving fitting standard bits, protrudes at the front from the gearbox  18 , which toward the front tapers to a rounded cone. The hexagonal socket  21  is provided with means that firmly hold the screwdriver bit or drill bit, inserted into it, in captive fashion so that for the axial removal of these bits, a certain resistance must be overcome by hand. 
         [0045]      FIG. 2  shows the battery-operated screwdriver  10  from the front; beyond what  FIG. 1  shows, the size ratios of the handle  14  to the length of the ON/OFF button  26  become clear. 
         [0046]      FIG. 3  shows a boxlike charger shell  22 , whose outer contour, viewed from the side, corresponds to a triangle standing on its base. The oblique faces are adapted to the pistol-shaped contour, facing toward them when the battery-operated screwdriver  10  is placed on them, of the battery-operated screwdriver  10  and are indented in groovelike fashion. The battery-operated screwdriver  10  can therefore enter with its inside into fitting embedding means  25  ( FIG. 8 ) for the handle  14  and for the motor housing  12  and gearbox  18  and can rest therein secured by its own weight; the contacting between its charge contact tongues  38  and the charge contacts  23  of the charger shell  22  is especially secure. 
         [0047]    The charge contacts  23  protrude upward out of the contour of the embedding means  25  of the charger shell  23 , so that when the battery-operated screwdriver  10  is placed in the corresponding embedding means  25  of the charger shell  22 , it is braced by its own weight, via its charge contact tongues  37 , on the resilient charge contacts  23  ( FIG. 8 ). Solely by placing the battery-operated screwdriver  10  on the intended place of the charger shell  22 , the charging state automatically ensues, with an audible click, as a result of mechanically secure contacting, as long as the charger shell  22  is connected to the power grid via its electric cord  24 . To that end, the electric cord  24  emerges at the left, in the viewing direction, from the charger shell  22  and extends to the power connection or the power supply of the charger shell  22 . 
         [0048]    In the rear region, associated with the handle  14  of the battery-operated screwdriver  10 , the charger shell  22  has a releasably clipped-in bit holder  99 . This bit holder has a plurality of insertion openings  95  for receiving standard screwdriver bits with a hexagonal shaft in captive fashion. The charger shell also, on its top in front of the bit holder  99 , has three further, fixed insertion openings  73  for screwdriver or drill bits. 
         [0049]      FIG. 4  shows an enlarged detail of the first half shell  16  with the individual parts inserted as in  FIG. 1 ; the design of the battery  40  with the adjoining parts as well as of the circuit board  36  with the parts secured to it and of the ON/OFF button  26  and the charge contact tongues  37  is clearly visible. 
         [0050]      FIG. 5  shows a view from the top on the battery-operated screwdriver  10 , seated in the charging position in the charger shell  22 ; in the viewing direction to the left next to the handle  14  and parallel to it, a red-colored bit holder  99  can be seen. For overlockable reception of the bit holder  99 , the charger shell  22  has a groovelike indentation  98 , which is undercut in some regions and is slightly narrower than the bit holder  99 . Since the bit holder is of elastic material, it can easily be positionally secured, snapping into the indentation  98 , when pressed firmly. 
         [0051]    The indentation  98  is longer than the bit holder  99 , so that once the bit holder  99  has been inserted in the indentation  98  the indentation remains free in a residual region  96  for being grasped from below or for removal of the bit holder  99  using one finger. 
         [0052]    Hexagonal bits  93  can be secured in captive fashion, held by force locking in spring-elastically constrictable compartments  95  in the magazine-like bit holder  99 , virtually perpendicular to the outer contour of the oblique faces of the charger shell  22 . 
         [0053]    At the top rear center, the battery-operated screwdriver  10  has one forward-pointing and one rear-pointing, arrow-shaped window  90 ,  92  each, beneath which an LED that indicates the direction of rotation is seated—as well as a rectangular window  91 , located between them, beneath which a charge control light is seated. 
         [0054]      FIG. 6  shows a view of the charger shell  22  obliquely from behind with the battery-operated screwdriver  10  placed on it. The removable bit holder  99  with approximately ten compartments  93  for inserting screwdriver bits as in  FIG. 5  can be seen along with the three fixed bit insertion openings  73  in the front region of the charger shell  22 . It can be seen that the bit holder  99  is fitted flush into the outer contour of the upper region of the charger shell  22 . 
         [0055]      FIG. 7  shows a side view of the charger shell  22  with the battery-operated screwdriver  10  placed on it, along with the bit holder  99  shown to the left of it in the viewing direction and located separately. 
         [0056]      FIG. 8  shows a top view on the charger shell  22 , looking toward the embedding means  25 , which is subdivided into a handle bed  251  and a gearbox bed  252 , so that the battery-operated screwdriver  10  can be placed flush and virtually without play, unambiguously and in foolproof fashion, in the charger shell  22  in such a way that it rests securely, and its charge contact tongues  37  ( FIGS. 1 ,  2 ,  4 ) gain a secure contact with the charge contacts  23  of the charger shell  22 . 
         [0057]    It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above. 
         [0058]    While the invention has been illustrated and described as embodied in a battery-operated screwdriver, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. 
         [0059]    Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention. 
         [0060]    What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.