Abstract:
A lift mechanism for a cleaning device of a dry shaving apparatus includes a base plate with guides and a chassis plate mounting the chassis and arranged for displacement relative to the base plate. Coiled-strip springs arranged on the guides spring-load the chassis plate against the base plate. On actuation of the lift mechanism the coiled-strip springs are untensioned by coiling up along the guides, thereby lifting the chassis plate. The coiled-strip springs reduce the load on the construction and ensure an almost noiseless lift mechanism.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This is a continuation of PCT application Ser. No. PCT/EP02/12887, filed Nov. 18, 2002, which claims priority to German Patent Application No. 102 10 351.8, filed on Mar. 8, 2002, which is incorporated herein by reference in its entirety. 

   TECHNICAL FIELD 
   This invention relates to a cleaning device of a dry shaving apparatus, with a base plate and a chassis arranged for displacement relative to the base plate, and a spring adapted to be secured therebetween. 
   BACKGROUND 
   A cleaning device of this type is known from the appliance of the Braun company sold under the name “Clean &amp; Charge”. This cleaning device includes a housing into which the dry shaving apparatus is inserted for cleaning purposes. This involves receiving the shaving head of the shaving apparatus in a receptacle designed as a cleaning bath. The housing further accommodates a reservoir containing a cleaning fluid. To clean the shaving head the cleaning fluid is fed from this reservoir into the receptacle. In the receptacle the cleaning fluid is caused to contact the shaving head in order to remove the hair dust collected in the shaving head. From the receptacle the cleaning fluid flows back into the reservoir, entraining with it the removed hair dust. The principle of operation of such a cleaning device is known, for example, from DE 44 02 237 C2. Considering that the effect of the cleaning fluid weakens with the number of cleaning processes increasing, it is necessary to substitute fresh cleaning fluid after a certain number of cleaning cycles. For this reason, the reservoir for the cleaning fluid is of the replaceable type. To replace the cleaning fluid reservoir, the housing of the cleaning device is opened by means of a lift mechanism, enabling the previous reservoir to be removed and a reservoir containing fresh cleaning fluid to be substituted. For this purpose, the cleaning device is divided into a base plate and a chassis. 
   The chassis is comprised of a chassis plate and the chassis proper. The base plate has guides for the spiral springs, said spiral springs being biased towards the chassis plate with the cleaning device in closed condition. Through a button provided on the outside of the housing the locked relationship between chassis and base plate is canceled and the lift mechanism is activated. The three spiral springs are untensioned and lift the chassis, thereby releasing the cleaning fluid reservoir for replacement. After the reservoir is replaced, the chassis is pushed down against the base plate, locking onto it at the same time. With the downward movement of the chassis the spiral springs are tensioned. Owing to the long opening travel of the housing it is necessary for the spiral springs to have a long spring excursion. At the same time the spiral springs have to hold the chassis securely in open condition. This necessitates relatively high forces for closing the housing and simultaneously tensioning the spiral springs. Moreover, these forces have a particularly strong effect also in closed condition because the spiral springs have a progressive spring characteristic. This puts a considerable strain on the structure of the cleaning device. Furthermore, the abrupt beginning and the abrupt end of the opening movement at a stop is accompanied by loud noise. On account of the long spring excursion the spiral springs are guided. On actuation of the lift mechanism the spiral springs come into contact with the guides, which likewise leads to a not insubstantial noise level. 
   It is therefore an object of the present invention to provide a cleaning device with a lift mechanism that operates as smoothly as possible, develops minimum possible noise while being of straight-forward construction, and puts little strain on the structure of the cleaning device. 
   SUMMARY 
   According to the present invention this object is accomplished by providing the lift mechanism with at least one coiled-strip spring. The chassis is spring-loaded against the base plate by the coiled-strip spring. With the cleaning device in closed condition, the coiled-strip spring is uncoiled. Actuation of the lift mechanism releases the chassis, which is then moved by the relaxing coiled-strip spring coiling up in the process. An advantage of a coiled-strip spring made of strip steel is its nearly linear spring characteristic and its almost noiseless operation. In addition, owing to the coiling motion impact-type contact with other components or with itself is prevented from occurring during both coiling up and uncoiling, but rather, the chassis is lifted at a relativity constant speed through the entire stroke travel. The coiled-strip spring hence can enable a substantially quieter lift mechanism. Moreover, the coiled-strip spring can reduce the load on the chassis so that the construction has to withstand less severe stresses, strains and loads. The provision of a suitable arrangement can render the coiled-strip spring, which coils up when the cleaning device is opened, invisible to the user. Therefore an additional surface treatment or encapsulation of the coiled-strip spring to enhance its appearance can be avoided. 
   Preferably, the base plate has at least one guide that supports the movement of the chassis. Apart from one guide disposed centrally on the base plate, the arrangement of several guides on the circumference of the base plate may also be considered. Arranging the guides on the circumference has the advantage that sufficient space is available in the center of the base plate for the cleaning fluid reservoir and other built-in components. Canting of the chassis plate is avoided if guide bushings having a long guide length are provided on the chassis. 
   This guide may be constructed at the same time as a guide for one or several coiled-strip springs. The use of two coiled-strip springs for each guide, referred to as twin coiled-strip springs, is advantageous in this connection. The arrangement of two coiled-strip springs allows the use of small springs, and also enables the symmetrical arrangement of the coiled-strip springs on a guide, which largely eliminates the risk of canting the chassis during the opening movement. 
   It is suitable to design two coiled-strip springs (twin coiled-strip springs) as a one-piece construction. In this design each end of a U-shaped length of strip steel is formed as a coiled-strip spring, with the two springs coiling up or uncoiling in outward direction. This enables both coiled-strip springs to be arranged on the guide with a single fastening. As a result, the number of single parts is reduced while at the same time the assembly is simplified. The coiled-strip springs may be fastened to the guide by frictional as well as positive engagement using, for example, screws, clips or rivets. 
   In another aspect the lift mechanism includes elements that slow down the movement of the chassis during opening of the cleaning device until the end position is reached. This can result in a noiseless opening movement, since the chassis is prevented from striking hard against a stop limiting the opening movement. Furthermore, decelerating the lift mechanism has a wear-reducing effect. 
   The elements for the decelerated lift mechanism can be elastic elements arranged either on the guide, the base plate or the chassis. The elastic elements may be spring, rubber, foam or other plastic parts which are moved against a stop. In this context, springs are advantageous because they allow slowing down of the lift mechanism through a relatively long travel. The stop may be arranged on the chassis as well as on the guides, preferably at the end remote from the base plate. Ease of assembly is accomplished by fastening the stop or the spring to the guide together with the coiled-strip spring. The use of spring clips is particularly suitable in this connection. These clips enable the fastening of the coiled-strip springs in addition to providing one or several springs for slowing down the opening movement of the chassis plate just before reaching the end position. 
   In another embodiment with the spring clips, the springs are bending springs cooperating each with a ramp disposed on the chassis. By suitably selecting the incline of the ramp a wide variety of different deceleration characteristics can be set. Thus a minor incline of the ramp results in a slow deceleration of the opening movement, while a major incline of the ramp produces a rapid deceleration. By varying the inclination over the distance to be covered it is possible to obtain combinations of the two decelerations. Thus it can be considered to provide the ramp initially with a small incline, which results in only a slow deceleration of the opening movement. As the chassis plate continues its approach to the end position, the ramp&#39;s incline increases, leading to a progressively increasing deceleration of the opening movement up to a complete stop. With suitable selection of the ramp design it is thus possible to set the end position in a defined manner. In this instance no additional stop for the lift mechanism is necessary. 
   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. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     An embodiment of the present invention will be described in the following. In the drawing, 
       FIG. 1  is a schematic view of a cleaning device; 
       FIG. 2  is an exploded view of the lift mechanism of the cleaning device; 
       FIG. 3  is a perspective view of the lift mechanism in retracted condition; 
       FIG. 4  is a side view of the lift mechanism in open condition; and 
       FIG. 5  is a side view of the guide of  FIG. 4 . 
   

   DETAILED DESCRIPTION 
   The cleaning device  1  shown in  FIG. 1  is comprised of a base plate  2  and a chassis  3 . The chassis  3  is composed of two housing parts  4 ,  5 . The shaving head of a dry shaving apparatus, not shown, is insertable into an opening  6 . Arranged underneath the chassis  3  are the devices needed for cleaning the dry shaving apparatus, such as the reservoir and the pump for the cleaning fluid and the lift mechanism. 
   The lift mechanism shown in greater detail in  FIG. 2  comprises the base plate  2  from which three guides  7   a - c  extend in upward direction. Slidably arranged along the guides  7   a - c  is a chassis plate  8 . To avoid canting of the chassis plate  8 , the chassis plate  8  includes three guide bushings  9 . The chassis plate  8  mounts the housing parts  4 ,  5  of the chassis  3 . Arranged on each of the guides  7   a ,  7   c  are two coiled-strip springs  10   a - d  which are able to coil up and uncoil along a guideway  11 . Each pair of coiled-strip springs  10   a, b;    10   c, d,  bent in a U-shaped configuration, are integrally connected with each other and fastened to the upper end of the respective guide  7   a ,  7   c  together with a respective spring clip  12  by two screws  15 . The spring clips  12  have two laterally arranged cantilevered portions  13  with inwardly bent tongues  14  supporting each other. For this purpose the guides  7   a,    7   c  have a respective recess  26  at the appropriate level. The tongues  14  may also be supported by corresponding surfaces of the guides  7   a,    7   c.  Arranged on the base plate  2  on a bridge are two detent hooks  16  which cooperate with a detent slide  17  to lock the chassis  3  onto the base plate  8  when the lift mechanism is in a retracted condition. The detent slide  17  has several detent bars  18  for engagement with the detent hooks  16 . To connect the detent slide  17  to the chassis plate  8 , hooks  20  are provided on the chassis plate&#39;s upper side. Shaped elements  21  disposed between the hooks  20  provide a guide for the detent slide  17 . A return spring  22  ( FIG. 3 ), likewise secured to the chassis plate  8 , effects movement of the detent slide  17  into a predetermined initial position. 
     FIG. 3  shows the chassis plate  8  in its retracted condition in which it is locked onto the base plate  2 . In this condition the detent bars  18  engage behind the detent hooks  16 . Together with the spring clips  12  the coiled-strip springs  10  are snap-locked on the guides  7   a,    7   c  or secured thereto by screws. With the chassis plate  8  locked in place, the coiled-strip springs  10  are tensioned due to uncoiling. The ends of the coiled-strip springs  10  are arranged within the guide bushings  9 . Operation of the actuating element  23  causes the detent slide  17  to be displaced along the shaped elements  21  in opposition to the return spring  22 . As this displacement occurs, the detent bars  18  are no longer in engagement with the detent hooks  16 , and the lift mechanism operates to cause the chassis plate  8  to be moved upwards along the guides  7   a - c.  After the actuating element  23  is released, the detent slide  17  is moved back to its initial position by the return spring  22 . The upward movement of the chassis plate  8  is effected by the coiled-strip springs  10 . The cleaning device  1  is thus open. To close the cleaning device  1 , the chassis  3  and chassis plate  8  are together moved downwards manually. During the downward movement of the chassis plate  8  the detent bars  18  of the detent slide  17  engage the detent hooks  16 . Lateral chamfers  19  on the upper side of the detent hooks  16  effect displacement of the detent slide  17  against the return spring  22  as the chassis plate  8  continues its downward movement. Once the chassis plate  8  is displaced downwards such a distance that the detent bars  18  are underneath the detent hooks  16 , the return spring  22  moves the detent slide  17  back into its initial position whereby the detent bars  18  engage behind the detent hooks  16 . The chassis plate  8  is thus again locked onto the base plate  2 , and the cleaning device  1  is closed. The audible locking action as the result of return spring  22  causing the detent bars  18  to strike against the detent hooks  16  is at the same time an audible signal informing the user of the cleaning device  1  that the lift mechanism is locked in place and the cleaning device closed. 
   The open cleaning device  1  is shown in  FIG. 4 . Guide bushings  9  formed on the chassis plate  8  receive the guides  7  of the base plate  2 . By means of suitable snap-locks and/or screws  15 , a spring clip  12  and the coiled-strip springs  10   c,    10   d  are fastened to the guide  7   c.  The two coiled-strip springs  10   c,    10   d  are bent in a U-shaped configuration and embrace the guide  7   c . The coiled up ends of the coiled-strip springs  10   c,    10   d  rest each against a respective stop  24  of the guide bushing  9 , thus spring-loading the chassis plate  8  against the base plate  2 . In the end position shown, the coiled-strip springs  10  are not completely untensioned, but possess sufficient bias to reliably hold the chassis plate  8  in the end position. The guide bushing has two masking plates  25  arranged in front of the coiled up ends of the coiled-strip springs  10 . These masking plates  25  protect the coiled-strip springs in addition to providing a sightproof guard so that that the coiled-strip springs  10  are not visible to the user when the cleaning device  1  is open. For closing the cleaning device  1 , the coiled up ends of the coiled-strip springs  10  are urged downwardly by the stops  24 , causing the ends to uncoil. The coiled-strip springs  10  are thereby tensioned. The coiled-strip springs  10  are constructed in such a way that the ends are coiled up in closed condition, that is, as shown in  FIG. 3 , in order to ensure reliable contact with the stops  24 . On actuation of the lift mechanism the guide bushings  9  slide with sliding surfaces  30  against the coiled-strip springs  10 . 
     FIG. 5  is a sectional view of the guide in its closed condition. In this view the chassis plate  8  is locked onto the base plate  2 . The spring clip  12  connected with the guide  7   c  has two lateral cantilevered portions  13  with inwardly bent ends  14  which extend into the recess  26  in the guide  7   c.  Arranged in the guide bushing  9  is a ramp  27 . The ramp  27  is arranged in such a manner that its distance to the guide  7   c  is progressively reduced from top to bottom. Opposite the ramp  27 , the guide bushing  9  has a limit stop  28  extending parallel to the guide  7   c.  At the lower end the limit stop  28  has an inwardly extending shoulder  29 . The attenuation of the lift mechanism just before reaching the end position will be described below. 
   As the chassis plate  8  is moved upwards, the ramp  27  strikes the cantilevered portion  13 . In continuation of this movement, the cantilevered portion  13  is bent inwardly. The end  14  is also deflected inwardly until it meets the opposite end  14 , urging it against the limit stop  28  of the guide bushing  9 . On account of this elastic deformation of the spring clip  12  the upward movement of the lift mechanism is slowed down. With an appropriate design of the ramp and the spring clip  12  deceleration of the lift mechanism and the end position of the chassis plate  8  can be set arbitrarily within wide limits. Thus, it can be considered to design the limit stop  28  likewise as a ramp. In the present case the end position is produced by positive engagement when the shoulder  29  formed in the guide  9  meets the right-hand cantilevered portion  13  of the spring clip  12 .