Patent Publication Number: US-8529001-B2

Title: Refrigerator with height-adjustable shelf for refrigerated goods

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a refrigeration appliance, in particular a household refrigeration appliance, having a housing and a shelf for refrigerated goods, the height of which can be adjusted in the housing. 
     Refrigeration appliances with horizontal guide grooves positioned at different heights on the side walls of the interior, into which guide grooves shelves for refrigerated goods can be introduced, are widely available on the market. Such a design allows the height of the compartments bounded by the shelves to be varied in each instance but only in discrete steps corresponding to the distance between the grooves. Height adjustment is laborious and time-consuming, since a shelf that is to be moved has to be emptied before it is pulled out and then refilled once it has been repositioned. 
     The refrigeration appliance described in the unprepublished German patent application DE 10 2007 029 176 A1 was designed to permit easy height-adjustment of a shelf for refrigerated goods without having to empty it beforehand. In this refrigeration appliance a shelf for refrigerated goods is supported by way of screws disposed at its corners on toothed profiles, which are permanently attached to an interior wall of the refrigeration appliance. The rotating bodies can be driven rotationally by way of a handle attached to the front edge of the shelf for refrigerated goods to adjust the height of the shelf for refrigerated goods. 
     The four rotating bodies of such a shelf for refrigerated goods have to be coupled to one another to ensure that all four corners of the shelf for refrigerated goods are displaced in the same manner and that the shelf for refrigerated goods does not tilt. The space required to integrate such a coupling is no longer available for the accommodation of refrigerated goods. To implement the height adjustment, a large number of different components are required, the manufacture and assembly of which increase the manufacturing costs of the refrigeration appliance. 
     BRIEF SUMMARY OF THE INVENTION 
     The object of the invention is to create a refrigeration appliance with an infinitely height-adjustable shelf for refrigerated goods, with which the space requirement and the complexity of a drive mechanism for height adjustment purposes are reduced. 
     The object is achieved in that with a refrigeration appliance having a housing and a shelf for refrigerated goods, the height of which can be adjusted in the housing, wherein at least one rotationally drivable screw of the shelf for refrigerated goods engages with at least one toothed profile fixed to the housing, the shelf for refrigerated goods is supported by way of a total of two screws on the housing in such a manner that its storage surface is disposed at least approximately horizontally. 
     The screws can be positioned on the shelf for refrigerated goods in such a manner that a vertical plane running through the axes of the screws contains the center of gravity of the support for refrigerated goods. To keep stable an arrangement of the center of gravity that is offset in respect of this plane, the support for refrigerated goods is preferably held in such a manner that it can be adjusted vertically in at least one guide rail that is fixed to the housing. 
     The guide rail can take on the guide function of one or more of the screws of the structure described in DE 10 2007 029 176 A1, so that the remaining screws can have the same positions as the screws shown there, at corners of the support for refrigerated goods. The maximum number of toothed profiles is 2 to correspond to the reduced number of screws. 
     These two toothed profiles are preferably disposed adjacent to an identical edge of the shelf for refrigerated goods. A significant torque occurs at the shelf for refrigerated goods, when it is supported vertically only by the two toothed profiles, due to its inherent weight and the weight of any refrigerated goods positioned thereon, but this torque can be absorbed with the aid of the guide rail so that the shelf for refrigerated goods still remains stable. 
     The positioning of the two toothed profiles adjacent to an identical edge of the shelf for refrigerated goods allows a transmission housing for a transmission coupling the screws to one another to be accommodated in a housing that extends in a space-saving manner just along this edge. 
     Said edge is expediently the rear edge of the shelf for refrigerated goods, both from a static point of view and in respect of the capacity for use of the interior of the housing. 
     In order to be able to drive the screws, a pivot arm preferably extends below a plate of the shelf for refrigerated goods up to its front edge, where it is easily accessible for a user. 
     The pivot arm is preferably coupled to the screws by way of a ratchet mechanism, so that the shelf for refrigerated goods can be moved over a large distance in a single, selectable direction by means of several to and fro movements of the pivot arm. 
     This ratchet mechanism can be directionally adjustable; this allows all the freedom of movement of the pivot arm to be utilized to drive a height adjustment in a single direction. 
     Alternatively the pivot arm can be able to be deflected out of a rest position in opposing directions, with the movement of the pivot arm on a first side of the rest position driving an upward movement of the support for refrigerated goods and the movement of the pivot arm on an opposite, second side of the rest position driving a downward movement of the support for refrigerated goods. 
     The two toothed profiles are preferably introduced in a space-saving manner into edges of the interior, between the rear wall and side walls of the housing. 
     Instead of projections projecting into the interior, such a toothed profile can expediently have cutouts to receive a turn of the screw in each instance in a flat outer surface facing the shelf for refrigerated goods. 
     To stabilize the support for refrigerated goods and in particular to absorb a torque acting thereon and at the same time to keep the friction to be overcome during the height adjustment low, the guide rail preferably has at least one surface opposite the toothed profile, on which at least one roller of the support for refrigerated goods rests. The roller permits the transmission of a considerable force in a horizontal direction, to compensate for the torque, without the height adjustment of the support for refrigerated goods being blocked by excessive friction between the support for refrigerated goods and the guide rail. 
     It is particularly preferable for the guide rail to feature two mutually opposing surfaces, with at least one roller of the support for refrigerated goods resting on each. This allows the support for refrigerated goods to be guided in a largely play-free, low-friction manner. 
     If the rollers that rest on different surfaces of the guide rail are also offset in relation to one another in respect of height, the rollers also permit relief for the screws and guide rails in respect of horizontal forces, thereby reducing the friction occurring during the height adjustment. 
     The guide rail is preferably a rib or groove that extends along a side wall of the housing. The opposing surfaces of the guide rail are then expediently side faces of the rib or groove. 
     A support profile featuring the guide rail and toothed profile can expediently be fitted on an edge between the rear wall and a side wall of the housing. This permits horizontal forces, which act between the shelf for refrigerated goods on the one hand and the guide rail or its toothed profile on the other hand, to be absorbed in the support profile and be compensated for, so that more stringent requirements do not have to be set for the bearing capacity of the housing walls. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further features and advantages of the invention will emerge from the description which follows of exemplary embodiments with reference to the accompanying figures, in which: 
         FIG. 1  shows a perspective, partially sectional view of a refrigeration appliance carcass with a height-adjustable shelf for refrigerated goods according to the invention; 
         FIG. 2  shows a partial side view of the shelf for refrigerated goods according to a first development of the invention; 
         FIG. 3  shows a horizontal partial section through the transmission housing and a support profile according to a second development; 
         FIG. 4  shows a section like the one in  FIG. 3  according to a third development; 
         FIG. 5  shows a horizontal section through a refrigeration appliance according to a second embodiment of the invention; 
         FIG. 6  shows a section along the plane marked VI-VI in  FIG. 5 ; 
         FIG. 7  shows a section like the one in  FIG. 1  according to a third embodiment; and 
         FIG. 8  shows an enlarged detail of the third embodiment in cross section. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE PRESENT INVENTION 
       FIG. 1  shows a perspective view of a section through a carcass  1  of a refrigeration appliance according to a first embodiment of the invention. It shows a base  2  and the lower halves of side walls  3 ,  4  and a rear wall  5  of the carcass  1 . The top of the carcass  1  is not shown, nor is a door, which is generally hinged to the carcass  1  to close off its open front face. 
     Shown in the interior  6  of the carcass  1  is a single height-adjustable shelf for refrigerated goods  7  but it is evident that a number of shelves for refrigerated goods  7  can be provided one above the other. The shelf for refrigerated goods  7  is supported by two support profiles  8 , only one of which is visible in  FIG. 1  and which are disposed opposite one another with mirror symmetry, each on an edge of the interior  6  between the rear wall  5  and the side walls  3  and  4 . The support profile  8  comprises a toothed profile  9 , which fills the edge of the housing, with a longitudinally extended planar surface  10 , which is at an angle of approx. 135° in each instance to the two adjacent walls  1  of the carcass, and a plurality of cutouts  11  let into the planar surface  10 . A vertical rib  12  is formed on a limb of the support profile  8  extending along the side wall  3 . 
     Screws—not visible in FIG.  1 —that engage in the cutouts  11  of the two support profiles  8  and can be rotated in each instance coupled into a vertical axis are accommodated in a housing  13 , which extends along a rear edge of the shelf for refrigerated goods  7  between the opposing support profiles  8 . Two narrow arms  14 , which extend forward from the housing  13  each narrowly adjacent and parallel to a side wall  3  or  4 , support a glass plate  15  of the shelf for refrigerated goods  7 . 
     A pivot arm  16 , which drives the screws by way of a ratchet mechanism accommodated in the housing  13  extends forward below the glass plate  15 . The direction of the ratchet mechanism can be adjusted in the known manner so that optionally for example a rotation of the pivot arm  16  in the clockwise direction drives an upward movement of the support for refrigerated goods  7  and a rotation of the pivot arm  16  leaves the support for refrigerated goods  7  unmoved, or the rotation in the counterclockwise direction leaves the support for refrigerated goods  7  unmoved, while the rotation in the counterclockwise direction drives a downward movement of the support for refrigerated goods. The length of the pivot arm  16  is dimensioned so that its front tip projects beyond the front edge of the glass plate  15  in any position it can assume, without however—at least in a position widely out to the side as shown in FIG.  1 —preventing the door closing. The pivot arm  16  can be guided in a horizontal rail in proximity to the front edge of the glass plate  15  for stabilization, e.g. in a slot in a web (not shown in  FIG. 1 ) connecting the front tips of the arms  14  together. 
       FIG. 2  shows a side view of the shelf for refrigerated goods  7  according to a first development of the embodiment in  FIG. 1 . A vertical hatched bar in  FIG. 2  is the rib  12  of the support profile  8  shown in cross section in this figure. One of the abovementioned two screws, here marked  19 , the turns  20  of which engage in the cutouts  11  of the toothed profile, can be seen in a window  17  in an angled wall  18  of the housing  13  facing the planar surface  10 . The engagement of the screws  19  permits the two support profiles  8  to absorb the weight of the shelf for refrigerated goods  7  but the shelf for refrigerated goods  7  is supported some distance away from its center of gravity so that the resulting torque has to be absorbed. In the simplest instance a projection of the housing  13  could be used for this, resting on a side  21  of the rib  12  facing the planar surface  10  above the screw  19 . 
     Because the projection and the screw  19  each transmit horizontal forces of opposing orientations to the rib  12  or the toothed profile  9 , it is possible to compensate for the torque but at the price of considerable friction between the surfaces of the projection and rib  12  or screw  19  and toothed profile  9  that are moved toward one another. 
     Such friction can largely be prevented on the part of the rib  12  in that a roller  22  presses against the side  21  rather than a rigid projection, as shown in  FIG. 2 . 
     In order also to relieve excessive friction on the screw  19  and toothed profile  9 , according to one expedient development a second roller  23  is disposed on the housing  13  below the first roller  22 , which presses the side  24  of the rib  12  opposite the side  21 . 
     A development illustrated in  FIG. 3  based on a horizontal section through the housing  13  functions mechanically in the same manner as the one in  FIG. 2 . As with this latter rollers  22 ,  23  with a height offset rest on opposing sides  21 ,  24  of the rib  12 , such that they are also offset from one another with regard to their vertical centerlines such that the two rollers do not substantially overlap one another when viewed from a vertical direction. The difference from  FIG. 2  is that instead of being positioned on one side in a floating manner on the outside of the housing  13 , the rollers  22 ,  23  are accommodated inside the housing  13  with axes fixed on two sides and the rib  12  engages through a vertical slot housing between the rollers  23 ,  24 . 
     Two engaging bevel wheels  41  connect the screw  19  to the ratchet mechanism disposed in the center of the housing  13 . 
     As also shown in  FIG. 3  the support profile is in two parts, having a basic profile  25  that is extrusion molded in a simple and low cost manner and has a cross section that remains the same and the toothed profile  9 , which is manufactured separately from the basic profile  25  and is introduced into its grooves  26 . 
       FIG. 4  shows an alternative development of the embodiment in  FIG. 1 , in which the mutually height-offset rollers  22 ,  23  of the shelf for refrigerated goods  7  rest on opposing sides  21 ,  24  of a groove  27  of the support profile  8 . 
     A second embodiment, which uses a single support profile  8  positioned centrally on the rear wall  5  of the carcass  1 , is shown in  FIG. 5  based on a horizontal section through a refrigeration appliance carcass. Since in this embodiment only a single screw  19  is present, no space is required for a coupling mechanism. The housing  13  must only provide space for the screw  19  and the ratchet mechanism driven by the pivot arm  16  and therefore does not extend from one side wall  3  to the other  4 . 
     A vertical guide rail is formed here by two ribs  28  that widen the toothed profile  9  and grooves  29  bounded between these and the rear wall  5  and open to the side in each instance. Rollers  30  supported by side walls of the housing  13  engage in these grooves  29 . Rollers  31  concealed in the interior of the housing  13  rest—with a height offset in respect of the rollers  30  as shown in the vertical section in FIG.  6 —on a front face of the ribs  28 . The roller pairs  30 ,  31  thus compensate for the torque of the shelf for refrigerated goods  7  and the screw  19  can be rotated with little friction. 
     A third embodiment shown in  FIG. 7  differs essentially from the one in  FIG. 1  only in the ratchet mechanism and the pivot lever driving it. While in  FIG. 1  the pivot lever can be moved continuously between two stops and over this entire movement, depending on the direction, either operates without load or drives an adjusting movement of the support for refrigerated goods in a uniform direction, the pivot lever  16  according to the third embodiment has a rest position, in which it projects forward from the housing  13  in a perpendicular manner and from which it can be deflected to the left or right against a reset spring, e.g. as far as the stop position shown in  FIG. 7 . Each rotation of the pivot lever out of the rest position drives a height adjustment of the support for refrigerated goods  7 , up or down depending on the rotation direction, while a reset movement of the pivot lever  16  back to the rest position drives the height of the pivot lever out of the rest position or leaves a height adjustment of the support for refrigerated goods unchanged. 
     In order to be able to close the door of the refrigeration appliance in the rest position, but on the other hand also to be able to grip the tip of the pivot lever  16  in the stop position, the length of said pivot lever  16  can be adjusted, as shown in the longitudinal section of the lever in  FIG. 8 , due to a telescopic structure of the level with a rod-type base segment  32  connected rigidly to the ratchet mechanism and a handle shaft  33  pushed onto it. The handle shaft  33  crosses a horizontally extended slot  35  in a stirrup  34  connecting the front ends of the support arms  14  and features contours, in the form of two grooves  36  here, in which the edges of the slot  35  engage to control the displacement of the handle shaft  33  along the base segment  32  according to the rotation of the lever  16 .