Abstract:
The invention is directed to an electrical appliance, in particular an appliance for hair removal or hair care, with at least one electric power unit, an electric circuit connected thereto and including an On/Off switch, and a fluid circuit feeding a fluid from a reservoir to an application site which is open to atmosphere and where fluid is withdrawn from the fluid circuit, wherein the On/Off switch, in overcoming an actuator travel, is switchable between two end positions and is coupled to an actuator of a shutoff valve of the fluid circuit.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This is a continuation of PCT Application No. PCT/EP02/14276, filed on Dec. 14, 2002, which claims priority to German Patent Application No. 102 17 987.5, filed on Apr. 22, 2002, which is incorporated herein by reference in its entirety. 

   TECHNICAL FIELD 
   This invention relates to an electrical appliance, in particular an appliance for hair removal and/or hair care, with at least one electric power unit, an electric circuit connected thereto and including an On/Off switch, and a fluid circuit feeding a fluid from a reservoir to an application site which is open to atmosphere and where fluid is withdrawn from the fluid circuit. 
   BACKGROUND 
   An electrical appliance of this type in the form of an electric shaving apparatus is known from DE 199 07 025 A1. The known appliance has an electric motor arranged in a housing and driving both the shaving unit of the shaving apparatus and a pump device. This pump device supplies a shaving and/or care fluid to an applicator element adapted to apply the fluid to the skin to be shaved or the hair. When the shaving unit is turned off, the pump device is also stopped, so that no more fluid is conveyed from the reservoir. However, it is still possible for fluid to leak out of the supply pipe connecting the fluid reservoir directly with the applicator, at least when the shaving apparatus is maintained in an inverted position for a prolonged time. It is also possible for fluid to escape undesirably through the throttle leading from the fluid reservoir to atmosphere. 
   It is therefore an object of the present invention to provide an electrical appliance which absolutely reliably prevents any inadvertent escape of fluid from the fluid circuit in particularly straightforward manner, with particularly low constructional effort, and with a minimum number of components. 
   According to an aspect of the present invention, this object is accomplished by providing for the On/Off switch to be switchable between two end positions, in particular between two stable end positions, in overcoming an actuator travel and to be coupled to an actuator of a shutoff valve of the fluid circuit. 
   The present invention may find application in a wide variety of electrical appliances which have a fluid circuit in addition to the electric circuit. These include, among other appliances, electric shavers affording the possibility of fluid application, epilators having such a fluid application possibility, steam irons, coffee or espresso makers or fluid-applying hair dryers or curling irons. 
   SUMMARY 
   A bistable pressure switch which has a cam control for controlling the actuator travel is preferably used as the On/Off switch. These pressure switches with cam controls of the type known, for example, from ball-point refills for generating their advancing movement, afford the advantage of creating an appreciable actuator travel in spite of compact construction, which can then be used effectively for actuation of the shutoff valve. 
   According to an embodiment of the invention which is of particularly straightforward construction and insusceptible to failure, the shutoff valve is realized as a clamping element capable of clamping together or releasing a hose section of the fluid circuit in dependence upon the position of the switch. 
   In another preferred embodiment of the invention, the shutoff valve is constructed as a seat valve or as a slide valve, in particular as a 2/2 directional control valve. The advantage of this embodiment is that it exhibits a particularly accurate control and switching characteristic and that the opening and closing behavior of such valves has no hysteresis and/or aging effects. 
   The On/Off switch may be manufactured particularly easily and with a very low number of components when it is acted upon by an interrupter spring which itself is part of an electric switching contact of the switch. Advantageously, the switching contact itself is then fabricated from an elastic material such as, for example, spring bronze. 
   Advantageously, the On/Off switch is coupled to an actuating rod one end of which forms the shutoff element of the shutoff valve. In order to ensure particularly reliable operation, it is an advantage for the actuating rod to be loaded by a spring element. When the spring element acts upon the shutoff valve in the closing direction, this reliably prevents fluid from escaping even in cases when components of the switching chain are defective. This additional spring element relieves the interrupter spring and enables the use of a two-part actuating rod whose manufacturing tolerances can be absorbed by the additional spring. 
   Further objects, features, advantages and application possibilities of the present invention will become apparent from the subsequent description of the embodiments. It will be understood that any single feature or any combination of single features described or represented by illustration form the subject-matter of the present invention, irrespective of their summary in the claims or their back-references. 

   
     DESCRIPTION OF DRAWINGS 
       FIG. 1  is a view of a dry shaver with a fluid applicator embodying the invention; 
       FIG. 2  is a greatly simplified, schematic view of the structural design of this embodiment; 
       FIG. 3  is a detailed view of another embodiment of the invention; and 
       FIG. 4  is a sectional view of a seat valve. 
   

   DETAILED DESCRIPTION 
     FIG. 1  is a perspective view of a dry shaving apparatus showing the rear side of the housing  1  and one of the two narrow sides  2  of the housing  1 . Provided at the upper end of the housing  1  is a shaving head  3  on which a fluid dispensing device  4  is provided. Attached to the narrow side  2  of the housing is a fluid reservoir  5 . This fluid reservoir may be fixedly or detachably connected to the housing. According to the invention, it is also possible for the fluid reservoir to be arranged in the interior of the housing in a fixed or replaceable manner. The fluid dispensing device  4  enables the metered application of a suitable shaving fluid and/or lubricant during the shave, regardless of the shaver position, whereby the shaving comfort can be enhanced appreciably. 
   In a manner known in the art, the shaving head  3  is comprised of a centrally located intermediate cutter  6  for shaving longer hairs. The intermediate cutter is disposed between two arched shaving foils  7  which cooperate with undercutters, not shown in the drawing, for shaving short hairs. The shaving foils  7  and the intermediate cutter  6  are mounted in a removable frame  8 . The fluid dispensing device  4  is secured to this removable frame  8  to ensure that the application of fluid takes place in direct proximity to the area to be shaved. In addition to receiving the fluid reservoir  5 , the housing  1  also accommodates an electric motor  10  which serves to drive the undercutters of the shaving head in an oscillatory manner as well as to drive a pump  11 . The pump can be driven either directly or indirectly. According to the invention, it is furthermore possible for the pump  11  to be driven by an electric motor assigned to it separately. The pump  11  is part of a fluid system communicating with the fluid dispensing device  4 , as shown in  FIG. 2  and explained in greater detail with reference to that Figure. 
   The pump  11  serves to operate the fluid circuit, conveying fluid from the fluid reservoir  5  to the fluid dispensing device  4 . For this purpose, the pump  11  has an inlet  12  and an outlet  13  with an integrated throttle. This throttle limits the operating pressure in the fluid system. Through a first fluid conduit  14 , the inlet  12  is connected to the applicator pocket  15  of the fluid dispensing device  4 . The pocket is constructed as an elongate recess in an applicator housing  16 . This first fluid conduit  14  is connected to the applicator pocket  15  in the pocket&#39;s left-hand end section when viewing the drawing. 
   Advantageously, the pump  11  is arranged in the interior of the fluid reservoir  5  which is constructed as a replaceable cartridge and is exchanged for a new one when the fluid is spent. 
   Depending on the amount of fluid consumed, the fluid reservoir  5  is filled with fluid  18  up to a specified level  17 , and the region below the maximum fluid level may be filled with a storage material for improved binding of the fluid. Open-cell sinter materials are particularly suitable for this purpose. Terminating in close proximity to and above the bottom  19  of the fluid reservoir  5  is a riser  20  which presents part of a second fluid conduit  21 . The fluid conduit  21  leads to the applicator pocket  15  to which it is connected in the pocket&#39;s right-hand end section when viewing the drawing. 
   The applicator element  22  is arranged in a firm press-fit in the applicator pocket  15  such that the upper region on which an applicator surface  23  is provided protrudes over and beyond the applicator housing  16 . The press fit between the applicator element  22  and the applicator housing  16  is only interrupted by at least one secondary-air duct  24  having an accurately defined flow cross-section. The applicator element  22  may be fabricated from a wick-type material or from a metal or plastics sinter material. Owing to its open-cell structure, it possesses a capillary effect for liquids leading to complete wetting. For operation of the fluid system, it is important for the cross-section of the secondary-air duct  24  to be matched exactly to the throttle in the pump outlet  13 . 
   In  FIG. 2 , the On/Off switch  25  is shown in the Off position. Accordingly, it can be seen that, in this position, the contact lug  26  is spaced from the contact element  27 . Through interposition of the electric motor  10 , the contact element  27  is connected to the negative terminal of a source of current, while the contact lug  26  is connected to its positive terminal. The interrupter spring  28  loads the pushbutton  29  of the On/Off switch  25  into the Off position. The contact lug  26  and the interrupter spring  28  are integrally formed and fabricated from an elastic material. At its end remote from the pushbutton  29 , the interrupter spring  28  is held with bias in a clamping device  34  formed fast with the housing. When the pushbutton  29  is actuated in the On direction (that is, towards the right in  FIG. 2 ), the interrupter spring is moved in opposition to its biasing direction. This movement is simultaneously transferred to the contact lug  26 , which moves in the direction of the contact element  27 , contacting it in electrically conducting fashion. This completes the electric circuit, turning the motor on. 
   Connected to the pushbutton  29  is an actuating rod  30  whose end remote from the pushbutton  29  is constructed as a clamp wedge  31 . The second fluid conduit  21  is passed between this clamp wedge  31  and its abutment  32 . The second fluid conduit  21  is of a hose-type configuration at least in the region of the clamp wedge  31 . This hose-type configuration is obtained using an elastic hose material compressible with low forces. The actuating rod  30  is loaded by a spring  33  taking support from the housing to which it is joined firmly. 
   In the Off position shown in  FIG. 2 , the electric motor  10  is turned off and the fluid conduit  21 , compressed by the clamp wedge  31 , is pressed against the abutment  32  in such a manner that fluid is not allowed to pass this point. Only when the pushbutton  29  is depressed does the pushbutton move to the right together with the actuating rod  30 . This motion causes the electric contact between the contact lug  26  and the contact element  27  to be closed and also displaces the clamp wedge  31  in opposition to the force of the spring  33  opening the flow cross-section between the wedge and the abutment  32 . 
   This arrangement ensures that fluid is not allowed to escape from the fluid reservoir  5  even when the electric shaver is in an inverted position. Because the throttle of the fluid system is disposed in the pump outlet  13 , that is, within the fluid circuit, thereby obviating the need to provide a pressure-relief valve towards atmosphere, the fluid circuit is completely sealed against atmosphere when the appliance is deactivated. In this condition, the turned-off pump  11  prevents any fluid from escaping through the first fluid conduit  14 . 
   When the motor  10  of the electric shaver is turned on by the On/Off switch  25 , it drives both the undercutters of the shaving head  3  and the pump  11 . Through the first fluid conduit  14 , the pump  11  initially draws air from the applicator pocket  15 . Like the applicator element  22 , the applicator pocket  15  contains no fluid initially. This enables aspirated air to be further supplied through both the pores of the applicator element and the secondary-air duct. This air is forced into the fluid reservoir  5  through the outlet  13  of the pump  11  and the throttle arranged in the outlet. The resulting pressure rise causes fluid  18  to be transferred via the riser  20  or the second fluid conduit  21  to the applicator pocket  15 . 
   Once the fluid has reached the applicator pocket  15 , a fluid stream develops in the lower region of this pocket, that is, between the mouths of the first and second fluid conduits. By virtue of its capillary effect, the arriving fluid is distributed in the entire applicator element  22  and transferred to the applicator surface  23 . Any excess fluid that the applicator element  22  is unable to take up is extracted by the pump  11  through the first fluid conduit  14  and returned to the fluid container  5 . 
   As long as the applicator element is still relatively dry and its pores mainly open, a very large volume of air is drawn by the pump  11 , which results in a very rapid pressure increase in the fluid reservoir  5 . This leads to a very rapid transfer of the fluid  18  to the applicator pocket  15 . With the fluid volume fed to the applicator element  22  increasing, its pores are gradually filled with fluid, and the secondary-air duct  24  is gradually closed by fluid. From this moment on, an operating state prevails in which initially no additional air can be aspirated into the fluid system. The applicator pocket  15  is prevented from overflowing and only a fluid circuit is maintained in circulation. Not until a certain amount of fluid has been dispensed through the applicator surface  23  is air again allowed to be supplied to the system through correspondingly evacuated pores or a released secondary-air duct  24 . This aspirated air volume then replaces the dispensed amount of fluid. The circulation system thus ensures that, during operation, the applicator element  22  is at all times sufficiently wetted, receiving an adequate supply of fluid  18 . 
     FIG. 3  shows another embodiment of the On/Off switch  25  and the shutoff element, coupled thereto, for the fluid conduit  21 . The On/Off switch is comprised of a pushbutton  29  coupled to a first camming element  35 . This first camming element  35  is situated in a stationary guideway  36  as is a second camming element  37  which is arranged between the first camming element  35  and an end piece  38  of the On/Off switch  25 . The end piece  38  is guided in the teeth of the guideway  36  in a non-rotating relationship thereto and has an actuating rod  30  integrally formed thereon at its end facing away from the pushbutton  29 . The camming elements  35  and  37  have facing spur teeth extending annularly around the circumference and having tips and roots. The second camming element  37  is rotatable relative to the first camming element  35  and the end piece  38  about the symmetry axis. Depending on whether the respective tips of the two gears stand end to end or whether the gears are in meshing engagement, a respective distance defining the actuator travel between the first camming element  35  and the end piece  38  will be set. Such camming elements are known in the art, for example, from the actuation of ballpoint refills to produce the advancing movement of these refills. 
     FIG. 3  shows the Off position of the On/Off switch  25 . In this position, the distance between the first camming element  35  and the end piece  38  is the minimum possible distance because the teeth of the first and second camming element are in meshing engagement. In this state, the contact between the contact lug  26  and the contact element  27  is open. The pushbutton  29  is surrounded by a membrane  39  connected to both the pushbutton and the housing  1  in a sealed relationship. The end piece  38  is elastically biased towards the pushbutton  29  by the interrupter spring  28 . 
   As already explained with reference to  FIG. 2 , the interrupter spring  28  and the contact lug  26  are integrally made of one piece and secured to the housing. Adjoining the actuating rod  30  is an intermediate member  40  which is biased towards the actuating rod  30  by means of the spring  33 . In its end region facing away from the actuating rod  30 , the intermediate member  40  has a clamp wedge  31  reaching behind the hose-shaped elastic section of the second fluid conduit  21 . Owing to the bias of the spring  33 , this clamp wedge  31  is urged to the left onto the fluid conduit  21  with such a high force that it compresses the fluid conduit, closing the fluid passage. As this occurs, the clamp wedge  31  forces the fluid conduit  21  against the abutment  32  constructed as hose guideway. Both the actuating rod  30  and the intermediate member  40  are mounted for longitudinal displacement in the housing  1 . 
   When the pushbutton  29  is depressed for a first time, the second camming element  37  rotates relative to the first camming element  35  through a predetermined angle, causing the respective tips of the two gears to lie end to end. As a result, an additional distance defining the actuator travel is set between the pushbutton  29  and the end piece  38 . Due to the displacement of the end piece  38  in the guideway  36  against the force of the interrupter spring  28 , electrical contact between the contact lug  26  and the contact element  27  is closed. In addition, the actuating rod  30  is displaced to the right. The rod then displaces the intermediate member  40  and the clamp wedge  31  to the right against the force of the spring  33 , thus canceling the clamping action on the second fluid conduit  21 . When the pushbutton is pressed a second time, the off-state shown in  FIG. 3 , in which the electric contact is open and the fluid conduit  21  is closed by being clamped together, is resumed. 
   In an alternative embodiment of the invention, the switching valve  45  shown in  FIG. 4  is integrated into the second fluid conduit  21 . The free end  46  of the arcuate connecting pipe  47  connects the switching valve  45  with the reservoir, while the free end  48  of the substantially tubular valve closure element  49  communicates with the applicator pocket  15  of the fluid dispensing device  4  through the second fluid conduit  21 . The valve closure element  49  is guided in the valve housing  50  in a through-bore  51  out of which it protrudes with its end  48 . The end of the through-bore  51  opposite the valve closure element  49  is closed by an elastomeric sealing seat  52 . The central bore  53  of the valve closure element can be closed by engagement of the valve closure element  49  with the sealing seat  52 . In this state, the connection between the fluid reservoir  5  and the fluid dispensing device  4  is interrupted. 
   Provided on the outer contour of the valve closure element  49  in the area of the end  48  is a circumferential groove  54  which is engaged by a coupling yoke  55  constructed as part of an actuating head  56 . The actuating head  56  in turn is connected to the actuating rod  30 —see  FIG. 2 . 
   A leg spring  57  is held on a bar-type projection  58  of the valve housing  50 , with the coil-type center portion of said leg spring  57  embracing the projection  58 . In this arrangement, the first leg  59  of the leg spring  57  elastically biases the actuating head  56  in a direction effecting closing of the valve closure element  49  coupled thereto. To this effect, the end of the second leg  60  takes support upon a stop  61  of the valve housing  50 . In the representation of  FIG. 4 , the switching valve  45  is open. When the pushbutton  29  was depressed, the actuating head  56  was displaced by the actuating rod  30  in opposition to the force of the leg spring  57 . As a result of which, the valve closure element  49  was caused to move into a direction away from the sealing seat  52 . The first leg  59  or the actuating head  56  then rests in an end position against a stop  63 . When switching off with the pushbutton  29 , the pressure force exerted by the actuating rod  30  is no longer present. The actuating head  56 , driven by the pressure force of the leg spring  57 , is moved back and the valve closure element  49  is urged into engagement with the valve seat  52 . Communication between the fluid reservoir  5  and the fluid dispensing device  4  is thus closed again. 
   In contrast to the hose clamping according to  FIGS. 2 and 3 , the switching valve  45  of  FIG. 4  dispenses with the sealing function obtained by deformation of the elastomeric hose section, resulting in an increased switching accuracy with active opening of the valve  45 . The use of the leg spring  57  enables a large actuator travel of the valve, which is necessary when the actuation is to take place with a considerable extra stroke by a cam control with a camming element according to FIG.  3 —see in this Figure the first camming element  35 , the guideway  36 , the second camming element  37  and the end piece  38 . 
   The section of the valve closure element  49  extending out of the valve housing  50  up to the groove  54  is encapsulated by an elastomeric bellows  62 . This bellows  62  also serves as a valve spring acting in opening direction—though with a low spring force. As a result, the switching valve  54  operates in particularly clearance-free manner, enabling extremely short actuator travels to be realized.