Abstract:
The invention is based on an electric device, in particular an electric hand tool, having a removable power supply unit ( 18, 70, 104 ), an accommodation region ( 16, 102, 132, 144, 156 ) for accommodating the power supply unit ( 18, 70, 104 ), and a locking device ( 20, 76, 114, 134, 146, 154 ) for locking the power supply unit ( 18, 70, 104 ) to the accommodation region ( 16, 102, 132, 144, 156 ). It is proposed that the locking device ( 20, 76, 114, 134, 146, 154 ) is provided for the purpose of unlocking the power supply unit ( 18, 70, 104 ) from a locked state—by means of a force which is exerted on the power supply unit ( 18, 70, 104 ) and moves the entire power supply unit ( 18, 70, 104 ) in relation to the accommodation region ( 16, 102, 132, 144, 156 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The invention described and claimed hereinbelow is also described in German Patent Application DE 10 2005 036 449.7 filed on Aug. 3, 2005. 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 
     The present invention relates to an electrical machine, in particular an electrical hand-held power tool. 
     Publication DE 38 41 735 A1 makes known an electrical hand-held power tool with a removable rechargeable battery and a holder for this rechargeable battery. The holder is provided with two actuatable, spring-loaded push-button blocks, which are used to secure the rechargeable battery in the installed state. To release the rechargeable battery, it is provided with a release push button. When the release push button is pressed, the blocks may be moved into a position that releases the rechargeable battery pack. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an electrical device, in particular an electrical hand-held power tool, with a removable power supply unit, a receiving region for receiving the power supply unit, and a locking device for locking the power supply unit in the receiving region. 
     It is provided that the locking device serves the purpose of unlocking the power supply unit from a locked state via an application of force, which is applied to the power supply unit and moves the entire power supply unit relative to the receiving region. A particularly easy procedure for removing a power supply unit that is locked in the receiving region is therefore attainable. In addition, the use of an additional unlocking device, e.g., additional actuating elements, may be eliminated, thereby enabling the electrical device to compact in design. 
     Advantageously, the locking device includes a locking element designed as a spring-loaded element, which, when released, is elastically deformed by the force into a state in which the power supply unit is released. Accidental unlocking by an operator may be advantageously ensured by the fact that the energy of a force applied to the power supply unit, e.g., the weight of the power supply unit, is converted to deformation energy of the spring-loaded element. 
     In a further embodiment, the spring-loaded element is formed by at least one leaf spring that includes an arresting projection. Space-saving, cost-favorable, existing elements may therefore be used, and a high service life of the locking device may be attained. The leaf springs may be held in a particularly secure manner, in the locked state in particular, via the arresting projection. 
     A particularly compact embodiment of the electrical device may be attained by the fact that the spring-loaded element is located in a space bounded by energy storage units of the power supply unit. The spring-loaded element may be located—for example, and particularly advantageously—in intermediate spaces formed in adjacent rechargeable battery cells of the power supply unit. 
     Assembly effort may be easily reduced by the fact that the electrical device includes a housing. The spring-loaded element is formed as one piece with the housing. The receiving region may be formed, e.g., by an inner surface of the housing. As an alternative, the housing may be formed by a housing of the power supply unit. 
     A particularly secure hold of the spring-loaded element may be attained by the fact that the spring-loaded element is engaged in arresting means when in the locked state. The locking means may be formed, e.g., by a recess in the receiving region, thereby enabling a compact design of the electrical device to be attained. 
     It is furthermore provided that the spring-loaded element is at least partially released when the power supply unit is guided along the receiving region, and it is loaded starting from this released state before locking occurs. The locking may be indicated in a particularly effective manner via the loading that takes place from the released state, in particular via a resistance that may be felt by the operator. The receiving region may be provided, e.g., with a recess for this purpose, and the spring-loaded element may release when it is guided into this recess. The recess also provides the advantage that, after unlocking, the spring-loaded element may be captured in the recess. 
     In a further embodiment of the present invention it is provided that the locking device includes a locking element and additional damping means, which are provided to elastically absorb energy produced via a relative motion between the power supply unit and the receiving region. This provides an additional level of assurance against accidental unlocking. 
     A particularly simple embodiment of the damping means may be attained by the fact that the power supply unit is movable relative to the locking element, and the damping means are formed by at least one element, which provided for deformation and is deformed when the power supply unit moves relative to the locking element. As a result, energy of motion may be absorbed by the damping means before the locking element is actuated. 
     When a strong load is placed on the electrical device, e.g., a shock, accidental unlocking may be prevented by the fact that the locking device includes a locking element and damping means, which are designed as a shock absorber and act on the locking element. In this context, “shock absorber” refers, in particular, to an element that has the property of reacting in a hard manner to dynamic loads, and of reacting in a soft manner to slow loads. The use of a thermoelastic elastomer that includes, e.g., a viscoelastic material, is particularly advantageous for this application. 
     In addition, foreign objects may be prevented from accidentally entering the power supply unit by the fact that an inner space of the power supply unit is insulated to the outside by the damping means. 
     Further advantages result from the description of the drawing, below. Exemplary embodiments of the present invention are shown in the drawing. The drawing, the description and the claims contain numerous features in combination. One skilled in the art will also advantageously consider the features individually and combine them to form further reasonable combinations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an electrical hand-held power tool with a removable power supply unit, 
         FIG. 2  shows an exploded view of the power supply unit in  FIG. 1  with a leaf spring and damping means, 
         FIG. 3  shows a receiving region of the electrical hand-held power tool with the power supply unit in  FIG. 1 , locked in the receiving region, 
         FIG. 4   a  shows a view of the damping means and the leaf spring in  FIG. 2 , from above, 
         FIG. 4   b  shows the damping means and the leaf spring in  FIG. 2 , from the side, 
         FIG. 5  shows the receiving region in  FIG. 3  with an alternative power supply unit, 
         FIG. 6  shows a housing for the electrical hand-held power tool with a receiving region and a further power supply unit, 
         FIG. 7  shows the power supply unit in  FIG. 6 , in a side view, 
         FIG. 8  shows a cross section through the housing in  FIG. 6 , 
         FIG. 9  shows a further housing with an inserted metal spring, in a side view, 
         FIG. 10  shows the housing in  FIG. 9 , in a perspective view, 
         FIG. 11  shows a further housing with a snap-to element, in a profile view, and 
         FIG. 12  shows a further housing with a segment, in a profile view. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An electrical device designed as an electrical hand-held power tool  10  is shown in  FIG. 1 . Electrical hand-held power tool  10  includes a motor housing  12  and a handle  14 . A receiving region  16  for receiving a removable power supply unit  18  and a locking device  20 —which is shown in greater detail in FIGS.  2  and  3 —are provided in handle  14 . Locking device  20  serves to lock power supply unit  18  to receiving region  16 . After unlocking, power supply unit  18  may be guided in a removing direction  22 . 
       FIG. 2  shows power supply unit  18 , in an exploded view. It includes an upper part  24 , a rechargeable battery housing  26 , and a lower part  28 . In an assembled state of power supply unit  18 , three energy storage units  30 —which are designed as rechargeable battery cells—are located inside rechargeable battery housing  26 , onto which upper part  24  is placed. Locking device  20 , which includes a locking element designed as spring-loaded element  34 , is located in a space  32  between two rechargeable battery cells. Spring-loaded element  34  is formed by a leaf spring and includes an arresting projection  36  designed as a lock-in projection, which, when power supply unit  18  is installed, extends out of an opening  38  of rechargeable battery housing  26 . Locking device  20  also includes damping means  40 , which are provided in the form of a thermoplastic elastomer. Locking device  20  also includes further damping means  42 , which are designed as a shock absorber, and in which spring-loaded element  34  is embedded. Spring-loaded element  34  and damping means  42  are movable relative to rechargeable battery housing  26 . 
       FIG. 3  shows receiving region  16 , which is formed by an inner surface of a housing  44  of electrical hand-held power tool  10 . Power supply unit  18  is locked in receiving region  16 , and arresting projection  36  of spring-loaded element  34  is engaged in arresting means  46 , which are designed as a recess in receiving region  16 . To securely hold spring element  34  in arresting means  46 , arresting projection  36  includes a surface  48  that forms an obtuse angle with removing direction  22 , thereby preventing surface  48  from sliding on a surface  50  of arresting means  46 . An inner space  52  bounded by rechargeable battery housing  26  is also insulated to the outside by damping means  42 , which prevent foreign objects from entering inner space  52  via opening  38 . To this end, damping means  42  include a projection  54 , which bears partially against a lateral surface  56  of rechargeable battery housing  26 . Furthermore, in the locked state, lower part  28  of power supply unit  18  may be gripped by an operator. 
     To unlock power supply unit  18  from receiving region  16 , an operator exerts a pulling force on lower part  28  in removing direction  22 . A relative motion between power supply unit  18  and spring-loaded element  34  results, and spring-loaded element  34  remains engaged in arresting means  46  of receiving region  16 . During this relative motion, damping means  40  are deformed by the pressure exerted by upper part  24 —they are compressed, in particular—and energy from the relative motion is therefore absorbed elastically as deformation energy of damping means  40 . A displacement W between spring-loaded element  34  and an edge  58  of opening  38  is provided for the relative motion. When lower part  28  is pulled on further, spring-loaded element  34 —its arresting projection  36 , in particular—is deformed elastically and disengages from arresting means  46 . Damping means  42  react to the deformation of spring-loaded element  34  in a soft manner to a pressure exerted by spring-loaded element  34 , and they are compressed. Unlocked power supply unit  18  may then be removed from electrical hand-held power tool  10  using a further pulling force on lower part  28 . To unlock, the operator may apply the pulling force with one hand to lower part  28  while he holds electrical hand-held power tool  10  with the other hand. The deformation of spring-loaded element  34  in the state in which power supply unit  18  is released takes place via a pulling force on lower part  28 , and no additional actuating elements are required. Accidental unlocking that may result from actuating elements located in handle  14  being actuated may therefore be prevented. 
     When a relative motion occurs between power supply unit  18  and receiving region  16  in the locked state, which is due, e.g., to strong vibrations of electrical hand-held power tool  10 , energy from this motion is absorbed via deformation of damping means  40  before spring-loaded element  34  is actuated. When stronger loads are applied, e.g., when electrical hand-held power tool  10  is dropped, spring-loaded element  34  may be actuated after damping means  40  are compressed, and strong pressure is applied to damping means  42  in a short period of time. Damping means  42  are formed of a thermoplastic elastomer, i.e., they are composed of polyurethane RAKU-PUR 33-C 166/16-5 made by the company Rampf Giesharze. This elastomer has a viscoelastic behavior and reacts in a hard manner to spring element  34  being pressed quickly. It offers strong resistance to spring element  34 , which has little play available for deformation, and does not easily disengage from arresting means  46 . When extreme loads are applied and spring-loaded element  34  disengages despite the resistance offered by damping means  42 , spring-loaded element  34  is captured in a recess  60  of receiving region  16 . Unlocked power supply unit  18  may be prevented from falling out immediately, since energy of motion may be converted to deformation energy of spring-loaded element  34  on a lower flank of recess  60 . 
     When power supply unit  18  is unlocked, recess  60  offers further advantages. Power supply unit  18  is guided along receiving region  16  more easily by the fact that spring-loaded element  34  is relieved of tension in recess  60 , and power supply unit  18  is prevented from falling out of electrical hand-held power tool  10 . To lock power supply unit  18 , spring-loaded element  34  is loaded from this unloaded state by gliding along a segment  62 , and the operator can clearly feel the resistance. When spring-loaded element  34  engages in arresting means  46  starting from this loaded state, this is indicated in a particularly effective manner, and it is clearly audible to the operator. 
     Damping means  40 ,  42  are shown in  FIG. 4   a , in a view from above. Damping means  42  include a section  64 , which bears against rechargeable battery cells indicated with dashed lines. Arresting projection  36  that extends out of projection  54  of damping means  42  is also shown. 
     Damping means  40 ,  42  and spring-loaded element  34  are shown in greater detail in  FIG. 4   b . Spring-loaded element  34  is embedded in damping means  42 , and its arresting projection  36  extends out of projection  54 . It also includes two loops  66  and  68 . Damping means  40 —which are shown separately from spring element  34  in the figure—may be inserted on loop  66 , or they may be formed thereon using injection moulding in another embodiment, with which assembly is simplified. 
     Receiving region  16 , on which a further power supply unit  70  is locked, is shown in  FIG. 5 . A locking element of a locking device  76  designed as spring-loaded element  72  is secured to power supply unit  70 . It includes an arresting projection  78 , which is designed as a lock-in projection and which is engaged in arresting means  46 . Power supply unit  70  includes a battery unit  80 , a rechargeable battery housing  82 , and a lower part  84 . Rechargeable battery housing  82  includes an opening  86 , in which a bolt  88  is located. A recess  90  is provided in battery unit  80  to move bolt  88  in opening  86 . A spring  92  is located between battery unit  80 —which is movable relative to rechargeable battery housing  82 —and rechargeable battery housing  82 . 
     To unlock power supply unit  70 , an operator exerts a pulling force on lower part  28 . As a result of this force, arresting projection  78  of spring-loaded element  72  is deformed, which presses bolt  88  into opening  86 . Arresting projection  78  may deform further as a result, until it disengages from arresting means  46 . Power supply unit  70  is therefore released and may be removed from electrical hand-held power tool  10  using a further pulling force on lower part  84 . When a load is applied, e.g., when electrical hand-held power tool  10  is dropped, and power supply unit  70  accidentally becomes unlocked, a relative motion between battery unit  80  and rechargeable battery housing  82  occurs, since battery unit  80  has greater inertia than rechargeable battery housing  82 . Spring  92  is therefore compressed. When battery unit  80  has moved by spring displacement X, a lateral surface  94  of recess  90  of battery unit  80  bears against a slanted lateral surface  96  of bolt  88 . A deformation of spring-loaded element  72  may be prevented in this position of battery unit  80 , since bolt  88  is prevented from being pressed into opening  86  by the fact that it bears against lateral surface  84 . As an alternative, a deformation of spring-loaded element  72  may be prevented when electrical hand-held power tool  10  is loaded by using a weight that is separate from power supply unit  70  and which is supported such that it is movable relative to receiving region  16 . When the load is applied that causes power supply unit  70  to become unlocked, a motion of the weight relative to receiving region  16  results until the weight bears against a blocking element, which prevents deformation of spring-loaded element  72 , as is the case with bolt  88  in  FIG. 5 . 
     A further housing  100  of electrical hand-held power tool  10  is shown in  FIG. 6 . An inner surface of housing  100  forms a receiving region  102 , on which a power supply unit  104  is locked. A rechargeable battery housing  106  with two guide rails  110  for guiding power supply unit  104  is shown. Rechargeable battery housing  106  includes three rechargeable battery cells  108 . Guide rails  110  engage in corresponding guide grooves  112  of receiving region  102  when guided along receiving region  102 . A locking device  114  is also shown, which includes a spring-loaded element  118 , which is designed as a wire spring and is inserted in groove  116 . At two diametrically opposed points, spring-loaded element  118  extends out of housing  100  in the form of two arresting projections  120 . When power supply unit  104  is locked to receiving region  102 , these arresting projections  120  engage in arresting means  122 ,  124 —which are designed as recesses—of power supply unit  104 . 
     Power supply unit  104  is shown in a side view in  FIG. 7 . Rechargeable battery housing  106  with guide rails  110  is shown. Arresting means  122 ,  124  include two diametrically opposed lateral surfaces  126 ,  128  of rechargeable battery housing  106 , each of which is provided for engaging a spring-loaded element on the device in receiving region  102  when locking occurs. 
       FIG. 8  shows a cross section through housing  100 . Spring-loaded element  118  that includes outwardly-extending arresting projection  120  and is inserted in housing  100  is shown. 
     An embodiment of a further housing  130  of electrical hand-held power tool  10  is shown in  FIG. 9 . Housing  130  forms a receiving region  132  for receiving power supply unit  104 . A locking device  134  is shown, which includes a spring-loaded element  138  that is designed as a metal spring and is inserted in a recess  136 . It includes an arresting projection  140 , which extends out of recess  136  and, in the locked state of power supply unit  104 , is engaged in arresting means  122  of power supply unit  104 . Housing  130  with spring element  138  inserted is shown in a perspective view in  FIG. 10 . 
     A further embodiment of a housing  10  of electrical hand-held power tool  10  is shown in  FIG. 11 . Housing  142  forms a receiving region  144  for receiving power supply unit  104 . A locking device  146  that includes a spring-loaded element  148  is shown. Spring-loaded element  148  is formed as one piece with housing  142 , and, in fact, in the form of a snap-to element with an arresting projection  150 , which is engaged in arresting means  122  when power supply unit  104  is in the locked state. 
     In the exemplary embodiment shown in  FIG. 12 , a spring-loaded element  152  of a locking device  154  is formed by a housing for electrical hand-held power tool  10  that is provided for deformation. The housing, which forms a receiving region  156  for receiving power supply unit  104 , includes an arresting projection  158  designed as a segment, which engages in arresting means  122  when power supply unit  104  is locked. 
     
       
         
               
             
               
               
             
           
               
                   
               
               
                 Reference numerals 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                  10 
                 Electrical hand-held power tool 
               
               
                  12 
                 Motor housing 
               
               
                  14 
                 Handle 
               
               
                  16 
                 Receiving area 
               
               
                  18 
                 Power supply unit 
               
               
                  20 
                 Locking device 
               
               
                  22 
                 Removing direction 
               
               
                  24 
                 Upper part 
               
               
                  26 
                 Rechargeable battery housing 
               
               
                  28 
                 Lower part 
               
               
                  30 
                 Energy storage unit 
               
               
                  32 
                 Space 
               
               
                  34 
                 Spring-loaded element 
               
               
                  36 
                 Arresting projection 
               
               
                  38 
                 Opening 
               
               
                  40 
                 Damping means 
               
               
                  42 
                 Damping means 
               
               
                  44 
                 Housing 
               
               
                  46 
                 Arresting means 
               
               
                  48 
                 Surface 
               
               
                  50 
                 Surface 
               
               
                  52 
                 Inner space 
               
               
                  54 
                 Projection 
               
               
                  56 
                 Lateral surface 
               
               
                  58 
                 Edge 
               
               
                  60 
                 Recess 
               
               
                  62 
                 Segment 
               
               
                  64 
                 Section 
               
               
                  66 
                 Loop 
               
               
                  68 
                 Loop 
               
               
                  70 
                 Power supply unit 
               
               
                  72 
                 Spring-loaded element 
               
               
                  76 
                 Locking device 
               
               
                  78 
                 Arresting projection 
               
               
                  80 
                 Battery unit 
               
               
                  82 
                 Rechargeable battery housing 
               
               
                  84 
                 Lower part 
               
               
                  86 
                 Opening 
               
               
                  88 
                 Bolt 
               
               
                  90 
                 Recess 
               
               
                  92 
                 Spring 
               
               
                  94 
                 Lateral surface 
               
               
                  96 
                 Lateral surface 
               
               
                 100 
                 Housing 
               
               
                 102 
                 Receiving region 
               
               
                 104 
                 Power supply unit 
               
               
                 106 
                 Rechargeable battery housing 
               
               
                 108 
                 Rechargeable battery cell 
               
               
                 110 
                 Guide rail 
               
               
                 112 
                 Guide groove 
               
               
                 114 
                 Locking device 
               
               
                 116 
                 Groove 
               
               
                 118 
                 Spring-loaded element 
               
               
                 120 
                 Arresting projection 
               
               
                 122 
                 Arresting means 
               
               
                 124 
                 Arresting means 
               
               
                 126 
                 Lateral surface 
               
               
                 128 
                 Lateral surface 
               
               
                 130 
                 Housing 
               
               
                 132 
                 Receiving region 
               
               
                 134 
                 Locking device 
               
               
                 136 
                 Recess 
               
               
                 138 
                 Spring-loaded element 
               
               
                 140 
                 Arresting projection 
               
               
                 142 
                 Housing 
               
               
                 144 
                 Receiving region 
               
               
                 146 
                 Locking device 
               
               
                 148 
                 Spring-loaded element 
               
               
                 150 
                 Arresting projection 
               
               
                 152 
                 Spring-loaded element 
               
               
                 154 
                 Locking device 
               
               
                 156 
                 Receiving region 
               
               
                 158 
                 Arresting projection 
               
               
                 W 
                 Displacement 
               
               
                 X 
                 Spring displacement