Patent Publication Number: US-2011056717-A1

Title: Self-contained portable electrical appliance with lock-on electric power pack

Description:
The present invention concerns a self-contained portable electrical appliance, in particular a portable electric tool such as a screwdriver, bolter or drill, the appliance being of the type comprising:
         an electrical unit;   an electric power pack comprising accumulators or batteries adapted to electrically power the electrical unit independently;       

     the electrical unit comprising a shell provided with a handgrip that extends in a handgrip extension direction Y-Y, said handgrip including a distal end comprising first connecting means, 
     the electric power pack including second connecting means adapted to cooperate with the first connecting means of the handgrip so as to removably connect the electrical unit and the electric power pack in a coupling position, 
     the handgrip and the electric power pack also respectively including first and second locking means, the first locking means being able to move in relation to the second locking means between a rest position and an unlocked position, such that, when the first locking means is in its rest position, the locking means locks, by mutual engagement, the electric power pack in relation to the handgrip in the coupling position, and that, when the first locking means is in its unlocked position, the first and second locking means are released from their mutual engagement, 
     the first locking means being connected to an actuator adapted to bring the first locking means into its unlocked position. 
     It is known from GB-A-2 425 899 to equip a self-contained portable electrical tool with a removable electric power pack, the foot of a distal end of the tool&#39;s handgrip having an elongated locking lever provided with a pushing end and a locking end. The lever makes it possible to manually uncouple the electric power pack and the handgrip of the electrical tool. The lever is able to move rotatingly in relation to a trunnion arranged at the foot substantially perpendicularly to the handgrip, between a locking position in which the end of the lever opposite the pushing end is engaged with a notch arranged at a face of the electric power pack, and a release position in which the locking end is disengaged from the notch of the electric power pack via action on the pushing end of the lever. 
     However, the design of such a locking lever does not allow optimal compactness of the foot of the tool&#39;s handgrip. 
     It is also known in the field of manufacturing self-contained portable electrical appliances to equip the electric power packs with one or two locking device(s) arranged on the outer shell of the electric power pack. However, this configuration of the locking device(s) is not easily accessible by the hand maintaining the appliance. 
     The invention aims to design a self-contained portable electrical appliance whereof the locking device is compact and ergonomic. Another aim of the invention is to simplify and decrease the manufacturing cost of the appliance. 
     To do this, the invention concerns a self-contained portable electrical appliance of the aforementioned type, characterized in that the first locking means is able to move in rotation between its rest and unlocked positions about an axis of rotation Y′-Y′ substantially parallel to the handgrip extension direction Y-Y. 
     According to other features:
         the actuator includes a protruding gripping portion arranged through an opening formed in the handgrip;   the first locking means of the handgrip comprises a male portion and the second locking means of the electric power pack comprises a female portion, the male and female portions being mutually engaged in the locked coupling position;   the male portion comprises a retractable cam connected to a trunnion forming the axis of rotation Y′-Y′ of the first locking means, the cam protruding in relation to a recess of the handgrip, and the female portion comprises at least one notch arranged fixedly in a wall of the electric power pack complementary to the cam of the handgrip;   the distal end of the handgrip comprises a connecting base, and the electric power pack includes a receiving portion adapted to cooperate with the connecting base by sliding along a sliding direction X′-X′, the sliding direction X′-X′ being substantially perpendicular to the handgrip extension direction Y-Y;   the first and the second locking means respectively comprise a first and a second male portions cooperating one stopped against the other in the coupling position; and   the first male portion is able to move slidingly in a bowed blind cavity arranged inside the handgrip, and the second male portion is fixed protruding arranged outwardly from the electric power pack.       

     Other features are described in the dependent claims. 
    
    
     
       The invention and its advantages will be better understood upon reading the description that follows, provided solely as an example and done in reference to the appended drawings, in which: 
         FIG. 1  is a side view of the self-contained portable electrical appliance according to the invention; 
         FIG. 2  is a bottom view of the foot of the handgrip of the portable electrical appliance of  FIG. 1 ; 
         FIG. 3  is a transversal cross-sectional view of the foot of the handgrip of the electrical appliance along line III-III of  FIG. 1 ; 
         FIG. 4  is an enlarged longitudinal cross-sectional view of detail IV of  FIG. 1  showing the foot of the handgrip of the electrical appliance; 
         FIG. 5  is a cross-sectional view of the foot of the handgrip of the electrical appliance along line V-V of  FIG. 1 ; 
         FIG. 6  is a top view of the locking device of the electrical appliance of  FIG. 1 ; 
         FIG. 7  is a side view of the locking device of the electrical appliance of  FIG. 1 ; 
         FIGS. 8 to 10  are top views of the electrical appliance showing different coupling and locking configurations between an electric power pack and the handgrip of the tool of  FIG. 1 ; 
         FIG. 11  is a top view of the electrical appliance showing the unlocked configuration between an electric power pack and the handgrip of the tool of  FIG. 1 ; 
         FIG. 12  is a side view of another embodiment of the electrical appliance according to the invention; 
         FIG. 13  is a rear view of the electrical unit of the electrical appliance of  FIG. 12 ; 
         FIG. 14  is a transversal cross-sectional view along line XIV-XIV of  FIG. 12 ; 
         FIG. 14A  is a front view of the reversible locking device of the appliance of  FIG. 12 ; 
         FIG. 14B  is a transversal cross-sectional view along line XIVB-XIVB of  FIG. 14A ; 
         FIG. 15  is a rear view of the electric power pack of the electrical appliance of  FIG. 12 ; 
         FIG. 16A  is a transversal cross-sectional view similar to  FIG. 14  showing the locking configuration between the electric power pack and the handgrip of the appliance of  FIG. 12 ; 
         FIG. 16B  is a view similar to  FIG. 16A  showing the unlocked configuration between the electric power pack and the handgrip of the appliance of  FIG. 12 . 
     
    
    
       FIG. 1  shows a self-contained portable electrical appliance  10  such as a bolter or an impact wrench according to a first embodiment. The appliance  10  comprises an electrical unit  12  extending along a longitudinal axis X-X oriented from right to left in FIG.  1 . The electrical unit  12  is adapted to be connected to an electric power pack  14  and to operate independently in relation to the electric network owing to accumulators or rechargeable batteries  15 . The latter are housed inside a housing  16  of the electric power pack  14 . 
     In  FIG. 1 , the housing  16  is shown in solid lines in a detached position in relation to the electrical unit  12  and in broken lines in a coupled position in relation to the electrical unit  12 . The latter position is obtained by a relative movement of the electric power pack  14  in relation to the electrical unit  12  along a direction illustrated by arrow F in  FIG. 1 . 
     When the electric power pack  14  is in the detached position in relation to the electrical unit  12 , the appliance  10  is not in operating condition. 
     When the electric power pack  14  is coupled to the electrical unit  12  in a locked position, the appliance  10  is in operating condition. For this, the electrical unit  12  comprises a first locking means  36  (see below) adapted to cooperate with a second locking means  77  (see below) arranged on the electric power pack  14  in order to obtain coupling in the locked position. 
     The first locking means  36  is able to move between a so-called rest position when the electrical unit  12  and the electric power pack  14  are coupled in the locked position or when they are detached, and a so-called unlocked position when the user wishes to detach the electrical unit  12  and the electric power pack  14  from their locked coupling position. 
     The electrical unit  12  also comprises a working head  17  that has a male profile with a square transversal cross-section making it possible to drive a tool  18  such as a bush. The working head  17  is arranged outwardly in relation to an outer shell  20  of the electrical unit  12 , the shell  20  forming a hollow envelope. 
     According to a traditional orientation of the appliance  10  as shown in  FIG. 1 , the front of the appliance  10  is situated on the side of the tool  18 . In contrast, the rear of the appliance  10  is situated on the side opposite the tool  18  along the longitudinal axis X-X of the electrical unit  12 , the axis X-X thus being oriented from back to front. 
     The terms “front” and “back” that will be used in the continuation of the description are understood according to that orientation. The terms “upper” and “lower” that will be used in the continuation of the description are understood according to the illustration of  FIG. 1 . 
     The electrical unit  12  also comprises a single-piece cap  23  fastened on the shell  20  so as to define a closed inner volume. 
     An electric motor  24  is housed inside the shell  20 , the motor  24  being coupled to a transmission  25 , itself housed inside the cap  23 . The working head  17  protrudes in relation to the cap  23  and coupled to the transmission  25 . 
     The electrical unit  12  is thus a driving part electrically controlled using a trigger  26  arranged at a connecting area between the shell  20  and a handgrip  28 . The latter extends along a direction Y-Y substantially perpendicular to the longitudinal axis X-X of the electrical unit  12 , the axis X-X and the direction Y-Y forming an angle α between 75° and 81°. 
     The handgrip  28  comprises a proximal end  28 A connected to the shell  20 , in particular in one piece therewith, and a distal free end  28 B that is distant from the shell  20 . A front portion  28 C of the distal end  28 B of the handgrip  28  is facing the trigger  26 . The distal end  28 B comprises a connecting base  30  having a flared shape allowing mechanical and electrical coupling between the electrical unit  12  and the electric power pack  14  for electrical powering of the motor  24 . 
     The base  30  has a terminal face  32  substantially perpendicular to the direction Y-Y of the handgrip  28 . 
     An opening  34 , defined by two side walls  34 A and  34 B, is arranged at the front portion  28 C of the distal end  28 B of the handgrip  28  facing the trigger  26 . 
     A reversible locking member  36  passes through the opening  34 , the manual activation of the reversible locking member  36  making it possible, from its rest position, to detach the electrical unit  12  in relation to the electric power pack  14  when they are coupled in the locked position. 
     The housing  16  is symmetrical in relation to a median plane S ( FIG. 3 ) and outwardly has a generally parallelepiped shape. It comprises an upper face  40 A and a lower face  40 B opposite the upper face  40 A. The upper face  40 A is oriented toward the working head  17  when the unit  12  and the power pack  14  are assembled. The lower face  40 B serves as a base for the power pack  14  to be placed on a plane. The lower face  40 B also serves as a base for the appliance  10  to vertically stand on a placement plane when the electrical unit  12  and the electric power pack  14  are assembled. 
     The housing  16  is made up of an upper shell  42  defining the upper face  40 A and a lower shell  44  defining the lower face  40 B, the shells  42  and  44  being assembled using suitable means. 
     The lower shell  44  has housings  46  intended to receive the accumulators or batteries  15 , for example using Lithium ion (Li-Ion) technology, these being arranged substantially parallel to the lower face  40 B. 
     In reference to  FIG. 2 , the connecting base  30  extends over a length l along a longitudinal axis X′-X′ oriented from back to front (from right to left in  FIG. 2 ) and perpendicular to the axis Y′-Y′ of the handgrip  28 . The axis X′-X′ is, consequently, substantially parallel to the axis X-X of the unit  12 . The base  30  comprises, from back to front, a slightly convex back wall  50  defining the terminal face  32  that extends longitudinally over about forty percent of the length l. A left side wing  52  (shown in the upper portion of  FIG. 2 ) and a right side wing  54  (shown in the lower portion of  FIG. 2 ) extend the terminal face  32  and extend longitudinally beyond it over about thirty percent of the length l. A frontal wall  55  substantially in the form of an arc of circle having a radius equal to about thirty percent of the length l defines the connecting base  30  in the front portion. 
     A generally rectangular recess  56  open at the front is arranged between the side wings  52  and  54 . A surface  57  substantially parallel to the terminal face  32  and offset in relation thereto toward the proximal end  28 A of the handgrip  28  extends from a bottom wall  58  of the recess  56  perpendicular to the axis X′-X′ to the frontal wall  55  of the connecting base  30 . 
     Two pins  59 A and  59 B are arranged protruding from the bottom wall  58  of the recess  56  toward the frontal wall  55 . The pins  59 A and  59 B extend parallel to the axis X′-X′ on both sides thereof, on the side wings  52  and  54  sides, respectively. They are adapted to electrically connect the electrical unit  12  and the electric power pack  14 . 
     The reversible locking member  36 , the operation of which will be described later, is shown in  FIG. 2  in the rest position corresponding to the configuration in which the electrical unit  12  and the electric power pack  14  are detached. 
     The reversible locking member  36  comprises a cam  60  arranged protruding in the recess  56  in front of the pins  59 A and  59 B. The cam  60  is connected to a cylindrical trunnion  61  having a circular transversal cross-section that extends along an axis Y′-Y′ parallel to the axis Y-Y. The cam  60  extends radially in relation to the trunnion  61  along a median axis Z′-Z′ ( FIGS. 2 and 6 ) forming an angle γ of about 132° with the axis X′-X′ in the rest position of the reversible locking member  36 . 
     The cam  60  is oriented toward the wing  52  of the connecting base  30 . An actuator  62  connected to the trunnion  61  extends radially in relation thereto in a direction substantially opposite that of the cam  60 . 
     The cam  60  has a transversal profile whereof the general flared shape includes a plurality of faces connected to each other ( FIG. 6 ). A first planar face  60 A connects the cam  60  to the trunnion  61  while diverging outwardly from the trunnion  61 . A second elongated planar face  60 B, substantially parallel to the axis Z′-Z′, extends the face  60 A, the faces  60 A and  60 B forming an angle θ of about 42°. A third bowed face  60 C with a radius centered on the axis Y′-Y′ extends substantially transversely to the face  60 B and cuts the axis Z′-Z′. A fourth elongated planar face  60 D connects the curved face  60 C to the trunnion  61 . An upper face  60 E and a lower face  60 F ( FIG. 7 ) define the cam  60  along the axis Y′-Y′. 
     The trunnion  61  includes an upper end  61 A and a lower end  61 B between which is arranged an intermediate portion  61 C ( FIG. 7 ). The cam  60  is connected to the lower end  61 B of the trunnion  61 , preferably in one piece therewith. 
     The actuator  62  is connected to the intermediate portion  61 C of the trunnion  61  at the upper half of the latter. The actuator  62  is preferably made in a single piece with the trunnion  61 . 
     In side view ( FIG. 7 ), the actuator  62  assumes a generally planar form defined by an upper face  62 A, a lower face  62 B and an inclined face  62 C with a slightly concave profile, connecting the upper  62 A and lower  62 B faces. The inclined face  62 C and the axis Y′-Y′ converge toward the upper end  61 A of the trunnion  61 . 
     In top view ( FIG. 6 ), the actuator  62  is shown in its rest position in relation to the axis X′-X′. The actuator  62  generally assumes the shape of an angle sector defined by two straight radial walls  62 D and  62 E forming an angle β of about 130° between them, the face  62 E angularly closest to the cam  60  and the axis X′-X′ forming an angle ψ of about 40°. An arc of circle shape defines the inclined face  62 C. 
     A gripping protrusion  63  extends substantially radially and outwardly from the inclined face  62 C of the actuator  62 , in the extension of the upper  62 A and lower  62 B faces. The gripping protrusion  63  is arranged radially substantially on the right bisector of the angle β. 
     The face  62 E of the actuator  62  also includes a receiving recess  64  ( FIGS. 4 and 5 ) whereof the function will be described later. 
     In  FIG. 2 , the connecting base  30  also comprises a protuberance  65  with a generally parallelepiped shape protruding from the surface  57 . The protuberance  65  includes two elongated side faces  65 A and  65 B parallel to the axis X′-X′, arranged on the side wings  52  and  54  side, respectively. The protuberance  65  also includes a rear face  65 C and a front face  65 D perpendicular to the axis X′-X′, as well as a lower face  65 E ( FIG. 4 ). The latter is arranged substantially in the same plane as the terminal face  32 . 
     The protuberance  65  inwardly comprises a cylindrical bore  66  extending along the axis X′-X′ and including a rear stop  66 A and a front stop  66 B ( FIG. 4 ). A first compression spring  67 A is housed in the bore  66 . The rear end  67 A′ of the first spring  67 A bears against the rear stop  66 A. The front end  67 A″ of the first spring  67 A bears against a pusher  67 B able to move longitudinally along the axis X′-X′. Under the effect of the bias from the first slightly compressed spring  67 A, the pusher  67 B bears against the front stop  66 B. 
     The protuberance  65  also comprises a first slot  68  arranged in the lower face  65 E, which extends along the axis X′-X′ over the forward half of the protuberance  65 . A second slot  69  is arranged in the front face  65 D of the protuberance  65  in the extension of the slot  68  and extends perpendicularly to the axis X′-X′. The slots  68  and  69  open in the bore  66 . 
     Under the effect of a force tending to push the pusher  67 B from the front toward the back, the latter is able to move from a rest position corresponding to its position bearing against the front stop  66 B of the bore  66  to a position in which it moves toward the rear stop  66 A of the bore  66  against the stress of the first spring  67 A. 
     In  FIG. 3 , the upper face  40 A of the electric power pack  14  comprises a receiving portion  70  extending over about the rear two thirds of the upper face  40 A of the housing  16  measured along the length L ( FIG. 8 ). The receiving portion  70  is adapted to receive, in a complementary manner, the connecting base  30  of the electrical unit  12 . 
     The receiving portion  70  comprises a support surface  71  adapted to cooperate with the terminal face  32  of the connecting base  30  of the electrical unit  12  when the electrical unit  12  and the electric power pack  14  are coupled ( FIGS. 8 to 10 ). The face  32  and the support surface  71  define a general assembly plane P between the electrical unit  12  and the electric power pack  14 . 
     Guide grooves  71 A and  71 B are arranged respectively on side walls  72 A and  72 B of the receiving portion  70  of the electric power pack  14 . The guide grooves  71 A and  71 B are adapted to cooperate with guide ribs  73 A and  73 B of conjugated shape arranged on the side wings  52  and  54 , respectively, of the connecting base  30  of the electrical unit  12 . 
     A middle guide plane P′, i.e. a guide plane situated midway between an upper guide face  72 C and a lower guide face  72 D of each guide groove  72 , is thus arranged substantially parallel to the general assembly plane P, slightly offset in relation to the general assembly plane P toward the upper face  40 A of the housing  16 . 
     The receiving portion  70  comprises, in front of the support surface  71 , a first and a second protuberances  74 A and  74 B ( FIG. 8 ) arranged on both sides of the plane of symmetry of the housing  16  on the side walls  72 A and  72 B sides, respectively. The protuberances  74 A and  74 B are adapted to cooperate with the recess  56  of the connecting base  30 . The protuberances  74 A and  74 B comprise a female electrical connector  75 A with positive polarity and a female electrical connector  75 B with negative polarity, respectively. The connectors  75 A and  75 B are adapted to be connected respectively to the pins  59 A and  59 B of the connecting base  30  in order to electrically power the electrical unit  12  from the electric power pack  14 . 
     The receiving portion  70  also comprises a middle groove  76  ( FIG. 8 ) that extends longitudinally and symmetrically on both sides of the middle plane of symmetry S of the receiving portion  70 , the plane S coinciding with the axis X′-X′ when the receiving portion  70  and the connecting base  30  are assembled. The middle groove  76  separates the protuberances  74 A and  74 B. 
     The middle groove  76  is rearwardly opened facing the support surface  71  of the receiving portion  70 . The middle groove  76  has dimensions adapted to allow, during coupling of the electric power pack  14  and the handgrip  28 , the passage of the protuberance  65  of the connecting base  30  with sufficient clearance so as not to interfere with the guiding of the grooves  71 A and  71 B and the respective guide ribs  73 A and  73 B of the receiving portion  70  and the connecting base  30 . The middle groove  76  comprises side walls  76 A and  76 B ( FIGS. 8 to 11 ) extending parallel to the plane of symmetry S of the receiving portion  70  and a forward wall  76 C substantially perpendicular to the plane of symmetry S of the receiving portion  70 . The side walls  76 A and  76 B are arranged respectively on the protuberances  74 A and  74 B side. 
     A notch  77  ( FIG. 8 ) is arranged in the side wall  76 A. The notch  77  is positioned longitudinally at about mid-length of the middle groove  76  such that the cam  60  and the notch  77  cooperate during locking of the coupling of the electric power pack  14  and the handgrip  28 , as will be described later. For this, the notch  77  has a partially bowed profile  77 A with a shape complementary to the third face  60 C of the cam  60 . 
     A tab  78  ( FIG. 8 ) is arranged longitudinally along the plane of symmetry S of the receiving portion  70  from the forward wall  76 C of the groove  76  toward the notch  77 . The dimensions of the tab  78  are adapted to cooperate with the slots  68  and  69  of the protuberance  65  of the connecting base  30  so as to come into contact with the pusher  67 B biased by the first spring  67 A of the connecting base  30  during coupling of the electric power pack  14  and the handgrip  28 , as will be described later. 
     In  FIG. 4 , the front portion  28 C of the distal end  28 B of the handgrip  28  inwardly includes an upper bearing  80 A and a lower bearing  80 B. The upper end  61 A of the trunnion  61  is in contact with the upper bearing  80 A while the intermediate portion  61 C of the trunnion  61  is in contact with the lower bearing  80 B. The bearings  80 A and  80 B are preferably made in a single piece with the handgrip  28 . The trunnion  61  is thus able to move rotatingly around its axis Y′-Y′. 
     The gripping protrusion  63  is arranged through the opening  34  formed in the front portion  28 C of the distal end  28 B of the handgrip  28 . The gripping protrusion  63  is adapted to be handled by one finger chosen from the index, middle, ring or little finger of the hand surrounding the handgrip  28 . 
     In  FIG. 5 , the actuator  62  is biased by a second compression spring  90  including a front end  90 A and a rear end  90 B. The front end  90 A bears in the recess  64  arranged in the face  62 E of the actuator  62 . The rear end  90 B bears against a transversal inner wall  92  of the handgrip  28 . 
     The second spring  90  biases the actuator  62  in the stable rest position of the reversible locking member  36 . The second spring  90  is weakly compressed and the gripping protrusion  63  of the actuator  62  abuts against the side wall  34 B of the opening  34  arranged in the front portion  28 C of the handgrip  28  ( FIG. 5 ) on the side wing  54  side of the connecting base  30 . The actuator  62  being in its rest position, the first face  60 A of the cam  60  is facing the rear face  65 C of the protuberance  65  ( FIGS. 2 and 8 ), distant therefrom with a small assembly clearance. As will be described later, under certain conditions, these two faces are brought into contact with each other. 
     The operation of the lock-on coupling of the electric power pack  14  and the handgrip  28  will now be described as well as the unlocking operation. 
       FIGS. 8 and 9  show the electric power pack  14  and the handgrip  28  in their coupled configuration corresponding to the transition between their detached position and their lock-on coupling position. 
     In reference to  FIG. 8 , the connecting base  30  is slidingly mounted in the receiving portion  70  along the direction shown by arrow F 1 . 
     The grooves  71 A and  71 B slidingly guide the conjugated ribs  73 A and  73 B. The protuberance  65  of the connecting base  30  is positioned inside the middle groove  76 . The cam  60  is in its rest position. 
     The pins  59 A and  59 B are aligned with the connectors  75 A and  75 B, respectively. Likewise, the pusher  67 B is aligned with the tab  78 . 
     In reference to  FIG. 9 , the relative sliding movement between the electric power pack  14  and the handgrip  28  along the direction illustrated by arrow F 1  is continued. 
     The protuberance  65  continues its travel inside the middle groove  76  toward the tab  78 . The second face  60 B of the cam  60  is in contact with the wall  76 B of the groove  76 , while the first face  60 A is no longer facing the rear face  65 C of the protuberance  65  of the base  30  in relation to the configuration of  FIG. 8 . The cam  60  is retracted in the groove  76  by counterclockwise rotation around the axis Y′-Y′ along arrow R 1  against the stress of the second spring  90 , which is compressed. 
     The pins  59 A and  59 B are in contact with the connectors  75 A and  75 B, respectively. The pusher  67 B is facing the tab  78  at a small distance therefrom. 
       FIG. 10  illustrates the electric power pack  14  and the handgrip  28  in the configuration corresponding to their lock-on coupling position. 
     In reference to  FIG. 10 , the relative sliding movement between the electric power pack  14  and the handgrip  28  is finished. 
     The protuberance  65  of the connecting base  30  is abutting against the forward wall  76 C of the receiving portion  70 . Under the detent effect of the second spring  90 , the third face  60 C of the cam  60  is engaged with the conjugated partially bowed profile  77 A of the notch  77 . The cam  60  has returned to its rest position by clockwise rotation around the axis Y′-Y′ along arrow R 2 . The first face  60 A of the cam  60  is again facing the rear face  65 C of the protuberance  65  of the connecting base  30 . 
     The pins  59 A and  59 B are fully engaged with the connectors  75 A and  75 B, respectively. 
     In the lock-on coupling configuration of the electrical unit  12  and the electric power pack  14 , the tab  78  is completely introduced into the slots  68  and  69 . During the coupling movement, the tab  78  acts on the pusher  67 B such that it moves longitudinally in the bore  66  toward the rear stop  66 A of the bore  66 . The relative movement between the pusher  67 B and the tab  78  results in compressing the first compression spring  67 A. 
     In response, the latter tends to detend and exerts a stress tending to separate the connecting base  30  and the receiving portion  70 . The cam  60  being engaged with the notch  77 , this separation is prevented. The connecting base  30  and the electric power pack  14  are coupled in relation to each other in the locked position. 
     In case of fall of the appliance  10 , the electrical unit  12  and the electric power pack  14  being coupled in the locked position, the energy of the shock must not be completely dissipated by the trunnion  61 . For this, because the first face  60 A of the cam  60  is facing the rear face  65 C of the protuberance  65  at a very small distance, the cam  60  is adapted, in case of shock, to abut against the protuberance  65  of the connecting base  30 . Thus, in case of shock, the trunnion  61  does not undergo significant stresses. 
       FIG. 11  shows the electric power pack  14  and the handgrip  28  in the configuration corresponding to their lock-on coupling position. 
     In reference to  FIG. 11 , the user wishes to detach the electric power pack  14  and the handgrip  28  of the electrical unit  12  in relation to each other. 
     To do this, the user voluntarily and manually moves the actuator  62  from a first so-called rest position corresponding to the configuration in which the cam  60 , shown in solid lines, is engaged in the notch  77  toward a second so-called unlocked position corresponding to the configuration in which the cam  60 , shown in broken lines, is disengaged in relation to the notch  77  and retracted into the middle groove  76  at the rear of the protuberance  65 . 
     To do this, the user grasps the gripping protrusion  63  of the actuator  62  and acts on it with a rotational movement in the counterclockwise direction in  FIG. 11  in relation to the axis Y′-Y′ by an angular value in the vicinity of 37° along arrow R 3 . This operation is done against the stress of the second compression spring  90 . 
     In the configuration corresponding to the so-called unlocked position in which the cam  60  is disengaged in relation the notch  77  and retracted in the middle groove  76 , the first spring  67 A detends and tends to separate the connecting base  30  and the receiving portion  70  along a longitudinal sliding movement shown by arrow F 2 . 
     This ejection movement of the electric power pack  14  in relation to the handgrip  28  continues until the pusher  67  resumes its rest position bearing against the front stop  66 B. 
     Once the first spring  90  is detended and the relative separation movement is obtained, the cam  60  is no longer facing the notch  77 , which allows the user to release the gripping protrusion  63 . When the cam  60  is no longer in contact with the middle groove  76 , the second spring  90  detends and the actuator  62  resumes its initial so-called rest position corresponding to the configuration in which the cam  60  is in its rest position. 
     The user manually uncouples the electrical unit  12  and the electric power pack  14  for a new coupling cycle with locking and detachment. 
       FIGS. 12 to 16B  show a second embodiment. In this embodiment, the elements having the same functions as in the first embodiment illustrated in  FIGS. 1 to 11  use the same numerical references as the first embodiment increased by 100. 
     The second embodiment differs from the first embodiment in that the electric power pack  114  is partially inserted in the handgrip  128  of a bolter or impact wrench  110  when the electric power pack  114  and the electrical unit  112  are in the coupling position. 
     When the electric power pack  114  is in the detached position in relation to the electrical unit  112 , the appliance  110  is not in operating condition. 
     When the electric power pack  114  is coupled to the electrical unit  112  in a locked position, the appliance  110  is in operating condition. For this, the electrical unit  112  comprises a first locking means  136  (see below) adapted to cooperate with a second locking means  200  (see below) arranged on the electric power pack  114  in order to obtain coupling in the locked position. 
     The first locking means  136  is able to move between a first so-called rest position when the electrical unit  112  and the electric power pack  114  are coupled in the locked position or when they are detached, and a second so-called unlocking position when the user wishes to detach the electrical unit  112  and the electric power pack  114  from their locked coupling position. 
     In reference to  FIG. 12 , the sliding movement between the locking position of the electric power pack  114  in relation to the handgrip  128  and the detachment position of these two elements is substantially parallel to the axis Y-Y of the handgrip  128 . 
     The handgrip  128  of the electrical unit  112  comprises a rear portion  128 D arranged at the distal end  128 B on the side opposite the trigger  126  in relation to the axis Y-Y. 
     The handgrip  128  also comprises a recess  195  adapted to partially receive the housing  116  of the electric power pack  114  with a shape adjustment of the housing  116  in relation to the recess  195 . The recess  195  has a transversal cross-section and a length complementary to those of the housing  116  in which the accumulators or batteries  115  are housed ( FIGS. 16A and 16B ). 
     The recess  195  extends along a direction substantially parallel to the axis Y-Y of the handgrip  128 . The recess  195  comprises a back wall  195 A arranged near the proximal end  128 A of the handgrip  128  and opens, opposite the back wall  195 A, in the terminal face  132  of the distal end  128 B of the handgrip  128 . 
     A first compression spring  167 A is connected to the back wall  195 A and comprises a free end  167 A′ ( FIG. 13 ). The first spring  167 A is adapted to be compressed in a direction substantially parallel to the axis Y-Y of the handgrip  128  when the electric power pack  114  and the handgrip  128  of the electrical unit  112  are in the lock-on coupled position. 
     The first spring  167 A, in the compressed state, tends to eject the electric power pack  112  outside the recess  195 . A reversible locking member  136  passes through a quadrilateral radial opening  134  ( FIG. 13 ) arranged outwardly in the rear portion  128 D of the distal end  128 B of the handgrip  128 . The reversible locking member  136  prevents the ejection by locking the electric power pack  114  in the coupling position inside the recess  195 . 
     The electric power pack  114 , illustrated vertically in  FIG. 15 , extends along a longitudinal axis T-T oriented from bottom to top. The housing  116  includes an upper face  140 A from which two protuberances  174 A and  174 B protrude longitudinally housing electrical connectors  175 A and  175 B, respectively. 
     The housing  116  also comprises a shoulder  171  successively defining, toward the bottom, a gripping portion  140 C extended by a lower face  140 B. The shoulder  171  is arranged radially protruding in relation to the longitudinal axis T-T in the lower third of the housing  116  measured in relation to the height t along the axis T-T of the electric power pack  114 . 
     In the lock-on coupling configuration of the electrical unit  112  and the electric power pack  114 , the shoulder  171  is adapted to bear against the terminal face  132  of the handgrip  128  and the gripping portion  140 C and the lower face  140 B are arranged outwardly in relation to the handgrip  128 . 
     A boss  200  extends outwardly protruding transversely in relation to the longitudinal axis T-T in the lower half of the housing  116  measured in relation to the height t of the housing  116 . 
     The boss  200  is arranged above the shoulder  171  radially in relation to an accumulator or a battery  115  having a circular transversal cross-section arranged longitudinally in relation to the axis T-T. 
     The boss  200  comprises an elongated planar side face  202  substantially parallel to the longitudinal axis T-T, an elongated lower planar face  204  substantially perpendicular to the longitudinal axis T-T and an elongated inclined planar face  206  connecting the side face  202  and the lower face  204 . The faces  202 ,  204 ,  206  form a protrusion having the general shape of a right-angled triangle. 
     When the electric power pack  114  is coupled in the locked position in relation the electrical unit  112 , the reversible locking member  136  is arranged between the terminal face  132  of the distal end  128 B of the handgrip  128  and the lower face  204  of the boss  200  of the electric power pack  114 . 
     In reference to  FIG. 14 , the recess  195  of the handgrip  128  comprises a transversal cross-section made up of three concave arc of circle lobes. One of the lobes  195 B is centered on an axis Y′-Y′ parallel to the axis Y-Y of the handgrip  128  and offset on the side of the rear portion  128 D of the handgrip  128 . The lobe  195 B comprises a circular profile whereof the radius r 1  is centered on the axis Y′-Y′. 
     The rear portion  128 D of the handgrip  128  comprises, facing the radial opening  134  of the distal end  128 B, a bowed inner blind cavity  210  arranged in the wall of the lobe  195 B. The inner blind cavity  210  extends over a height along the axis Y-Y substantially corresponding to that of the radial opening  134  and communicates therewith. 
     A longitudinal groove  220  ( FIG. 13 ) extends, from the terminal face  132 , substantially parallel to the axis Y-Y along the sliding direction of the electric power pack  114  in relation to the recess  195 . The longitudinal groove  220  opens in the inner blind cavity  210  and extends longitudinally along the axis Y-Y beyond the radial opening  134  ( FIG. 13 ). The longitudinal groove  220  is adapted to slidingly receive the boss  200  of the housing  116  of the electric power pack  114 . The longitudinal groove  220  includes two radial walls  230  and  232  in relation to the axis Y-Y′ that form an angle φ 1  of about 30° between them. 
     The outer opening  134  is defined by a left radial wall  134 A and a right radial wall  134 B and a circular wall  222  whereof the radius r 2  is centered on the axis Y′-Y′, the radius r 2  being greater than the radius r 1 . 
     The bowed inner blind cavity  210  is defined by a first inner wall  224  whereof the radius r 3  is centered on the axis Y′-Y′ and a second inner wall  226  whereof the radius r 4  is also centered on the axis Y′-Y′. The radius r 4  is larger than the radii r 2  and r 3 . The radius r 2  is larger than the radius r 3 , the latter being larger than the radius r 1 . The bowed inner blind cavity  210  is defined by a bottom wall  228  arranged radially in relation to the axis Y′-Y′. 
     In reference to  FIG. 14A , the reversible locking member  136  comprises an upper face  240  and a lower face  242 . 
     In reference to  FIG. 14B , the transversal cross-section of the reversible locking member  136  comprises a profile adapted to slide in relation to the respective profiles of the outer radial opening  134  and the bowed inner blind cavity  210  so as to selectively cover the longitudinal groove  220 . 
     For this, the reversible locking member  136  extends along an angle sector with apex ◯ and about 75°. It comprises a gripping protrusion  163  outwardly radial in relation to the apex ◯ and defined by two radial walls  163 A and  163 B. A locking block  250  is arranged opposite the gripping protrusion  163  and extends inwardly radially in relation to the apex ◯. 
     An intermediate actuator  252  connects the gripping protrusion  163  and the locking block  250 . A right radial planar face  254  and a left radial planar face  256  radially define the locking block  250  and form an angle φ 2  between them, the latter being slightly larger than the angle φ 1  formed by the radial walls  230  and  232  of the inner longitudinal groove  220 . A bowed face  258  centered in ◯ and the radius of which is equal to the radius r 3 , connects the radial faces  254  and  256  of the locking block  250 . Two bowed faces  260  and  262  inwardly and outwardly, respectively, define the intermediate actuator  252  of the reversible locking member  136  in relation to the apex ◯. The face  260  is centered in ◯ and has a radius equal to the radius r 2 . The face  262  is centered in ◯ and has a radius equal to the radius r 4 . 
     Preferably, the reversible locking member  136  is formed in a single piece. 
     The walls  222 ,  224 , and  226  arranged in the rear portion  128 D of the handgrip  128  are adapted to slidingly guide the faces  260 ,  258  and  262 , respectively, of the reversible locking member  136  along an arc of circle centered on the axis Y′-Y′. The reversible locking member  136  thus moves in rotation in relation to the axis Y′-Y′. 
     In reference to  FIGS. 16A and 16B , the bowed inner blind cavity  210  houses a second compression spring  190  whereof the front end  190 A bears against the outer radial face  254  of the locking block  250  of the reversible locking member  136  and whereof the rear end  190 B bears against the radial bottom face  228  of the bowed inner blind cavity  210  of the handgrip  128 . 
     In reference to  FIG. 16A , the reversible locking member  136  is in its rest position. The second spring  190  is detended and biases the reversible locking member  136  such that the gripping protrusion  163  abuts against the left radial wall  134 A of the outer radial opening  134  of the handgrip  128  farthest from the bottom radial face  228  and the locking block  250  covers the inner longitudinal groove  220 . 
     This configuration corresponds to that in which the electrical unit  112  and the power pack  114  are detached or coupled in the locking position. 
     When the electrical unit  112  and the power pack  114  are detached and the user wishes to couple them, the user introduces the electric power pack  114  into the recess  195  of the handgrip  28  through a relative sliding movement along axis Y-Y. 
     The boss  200  is dimensioned so that it slides longitudinally in the inner groove  220  when the user introduces the electric power pack  114  into the recess  195 . The side planar face  202  of the boss  200  is adapted to be longitudinally aligned with the radial face  230  of the inner longitudinal groove  220  farthest from the radial bottom face  228 . 
     When the user continues the introduction of the electric power pack  114 , the inclined face  206  of the boss  200  comes into contact with the locking block  250  of the reversible locking member  136 . When the introduction continues, the reversible locking member  136  is moved inside the bowed inner blind cavity  210  against the stress of the second compression spring  190 , the face  206  forming a cam for the boss  200 . The reversible locking member  136  is moved in rotation around the axis Y′-Y′ in the counterclockwise direction shown by arrow R 1  of  FIG. 16A . 
     When the boss  200  is arranged longitudinally along the axis Y-Y such that the lower face  204  is facing the upper face  240  of the reversible locking member  136 , the second spring  190  detends and biases the reversible locking member  136  such that the reversible locking member  136  moves in rotation in relation to the axis Y′-Y′ in a clockwise direction illustrated by the arrow R 2  of  FIG. 16A  and returns to its rest position. The locking block  250  again covers the inner longitudinal groove  220 . The electrical unit  112  and the electric power pack  114  are coupled in the locking position. 
     In the lock-on coupling configuration, the boss  200  of the electric power pack  114  is blocked in the longitudinal position along axis Y-Y. The electric power pack  114  abuts axially in the recess  195  and the upper face  140 C of the housing  116  compresses the first compression spring  167 A. The pins  159 A and  159 B are in contact respectively with the connectors  175 A and  175 B in order to electrically power the electrical unit  112 . 
     When the user wishes to detach the electric power pack  114  in relation to the electrical unit  112  from their locking coupling configuration, the user uses the gripping protrusion  163  that is arranged through the outer radial opening  134  arranged in the rear portion  128 D of the handgrip  128 . The gripping protrusion  163  is adapted to be handled by the thumb of the hand whereof the palm surrounds the handgrip  128 . 
     The user manually and voluntarily moves the reversible locking member  136  in rotation around the axis Y′-Y′ in the counterclockwise direction illustrated by the arrow R 3  shown in  FIG. 16B . 
     For this, the user grasps the gripping protrusion  163  and moves it toward the right radial wall  134 B of the outer opening  134 , the wall  134 B being closest to the bottom wall  228  of the inner blind cavity  210 . The locking block  250  slides inside the bowed inner blind cavity  210  against the stress of the second spring  190 . The locking block  250  releases the inner longitudinal groove  220 . 
     The user maintains the stress on the gripping protrusion  163  along the arrow R 3 . The first compression spring  167 A that is compressed, biases the electric power pack  114  so as to separate it from the electrical unit  112  by an ejection effect. Under the detent effect of the first spring  167 A, the boss  200  slides along the inner longitudinal groove  220 . When the electric power pack  114  is sufficiently removed from the handgrip  128 , the boss  200  is positioned outside the inner longitudinal groove  220 . The user relaxes the stress on the gripping protrusion  163  such that the reversible locking member  136  returns to its rest position for a new coupling cycle with locking and detachment. 
     In the preceding, the appliance was described in the form of a bolter or impact wrench. However, the present invention applies to other types of appliances such as a screwdriver or drill. 
     Owing to the invention, the self-contained portable electrical appliance has a compact and ergonomic locking device, inserted in the handgrip. The manufacture thereof is simple and economical.