A no-frost refrigerator having an opening in a separating wall for the through passage of air between a storage chamber and an evaporation chamber. A control element is arranged in the opening and can be displaced or shifted between positions in which the control element covers the opening to different extents. The control element can be rotated about an axis substantially perpendicular to an axis or plane of the air passage opening.

The present invention relates to a no-frost refrigerator. Such a refrigerator conventionally comprises in a heat-insulating housing a storage chamber for accommodating cool goods and an evaporation chamber, in which an evaporator is arranged and which is connected to the storage chamber via an air passage. Air is circulated between both chambers to cool the storage space via the air passage. The separation of storage chamber and evaporation chamber enables the evaporator to defrost when required, without this necessarily leading to heating of the storage chamber.

For the purposes of regulating the strength of the air exchange between evaporation chamber and storage chamber and to prevent this air exchange as fully as possible when the evaporator defrosts, a control body, which can be shifted between different positions, is usually provided in the air passage of such a unit, in which it covers the free cross-section of an air passage opening in the air passage to different extents. There are diverse constructions of such control bodies in use, e.g. flaps pivotable about an axis, slides displaceable in the plane of the air passage opening etc. In the case of a slide there is the risk that it will freeze solid on the wall surfaces limiting the air passage opening and accordingly cannot fulfil its task at least temporarily.

The problem of freezing solid can be reduced in a suitably constructed flap, though the disadvantage here is that to swing out it requires considerable spatial depth, which adds up to lost useable volume for the storage space. It would be conceivable to reduce this space requirement, where a plurality of narrow flaps is used in place of a single wide flap, yet this detracts from the robustness of the refrigerator and adds costs to its manufacture.

The aim of the invention is to provide a no-frost refrigerator with a robust regulating mechanism for air exchange between both chambers, in which both the risk of freezing solid and space requirement are minimised.

This task is solved according to the present invention by a refrigerator having the features of Claim1.

Through rotatability of the control body about an axis vertical to the plane of the air passage opening a minimal structural depth of the respective position of the control body independent of the regulating mechanism is achieved, which also enables the rotatable suspension of the control body, to avoid any contact between the control body and parts bearing it downstream of the axis. But possible freezing solid in the immediate vicinity of the axis does not give rise to any serious problems, since the control body can break lose with minimal expenditure of force.

The air passage opening is preferably formed directly in a partition between storage chamber and evaporation chamber; alternatively it could also be formed in a wall of a channel connecting the two chambers.

The passage opening extends with respect to the axis of revolution through an angle of less than 180°, so that a recess congruent with the air passage opening of the control body can constantly be brought into a position, in which air passages and recesses do not securely overlap.

The control body is preferably formed as a circular disc. This facilitates its arrangement in a cylindrical housing, and the edge of such a control body can also be easily embodied as a cam disk, which can be used for controlling a drive motor in particular for the control body by means of a switch.

The axis is preferably formed by a shaft of a drive motor of the control body, taken up in a sleeve of the control body. To anchor the control body solidly on the shaft, though still easily detachable, a locking element can be provided which crosses slots of the sleeve and of the shaft oriented in a common plane and formed obliquely to the axis and thus blocks axial shift of both against one another.

The locking element is preferably held at one end on the control body and has an elastically mobile second end. Through displacement of the locking element out of one of the slots the axial coupling of the control body can be lifted on the shaft.

And to protect the locking element or to prevent interlocking of foreign bodies, the locking element is preferably set in between the control body and a wall, on which the control body is swivel-mounted, in particular the partition, and its capacity for actuation and detachability is guaranteed, in that in the control body a hole is made, through which the free end of the locking element can be activated, if required by means of a tool.

It is also preferred that the air passage opening is formed in a substantially cylindrical shell element, inserted into a wall such as the partition. This shell element can be pre-mounted along with the control body as an assembly and then set into a recess of the wall provided for this purpose, through which assembly of the refrigerator is facilitated.

A heating unit can be provided on the periphery of the shell element, to securely exclude freezing solid of the control body in the vicinity of its peripheral surface.

The abovementioned drive motor for the control body is preferably likewise pre-mounted on the shell element, to be placed in the refrigerator jointly with the latter.

To prevent flow-obstructing turbulence and the penetration of moisture between the control body on the one hand and the partition or respectively the shell element on the other hand as extensively as possible, a support facing the control element is preferably formed on the air passage opening.

To prevent moisture adhering to the support from reaching the shaft, the walls of the support above the shaft are preferably convex in an upwards direction.

FIGS. 1 and 2are in each case perspective exploded views of an assembly, provided to be mounted on a passage or in a passage52of a partition54between the storage chamber56and the evaporation chamber58of a no-frost refrigerator50, as shown inFIG. 8, preferably directly below the cover of the storage chamber, to form an air passage opening with an adjustable cross-section.FIG. 1shows the assembly more from the front side andFIG. 2more from the rear. The descriptions front and rear sides are selected at random. The assembly can be mounted in the partition with the front side facing the evaporation chamber and the rear side facing the storage chamber, or vice versa, whereby however the arrangement of the rear side facing the storage chamber is preferred for the configuration shown here.

The assembly is composed substantially of a flat cylindrical shell1, open on a front side, which forms an outer limit of the assembly, and whereof the cylindrical outer wall2in the mounted state is built into the circular passage of the partition. The shell1and the partition thus form a partition between evaporation chamber and storage chamber, which is closed up to an air passage opening3formed in the shell1itself. The fitting position of the assembly is selected such that the air passage opening3is as high as possible.

A short support4with a sickle-shaped cross-section is formed on the inside of the floor of the shell1and extends in its inner space. An outer wall section of the support4extends at a short distance to the outer wall2of the shell1concentric thereto. An inner wall section of the support4is likewise curved like the arc of a circle, with a lesser radius of bending than the outer wall section.

The outer wall2is pierced at a point on its periphery to form a mounting for a key button5, from which a stylus6projects into the interior of the shell1when in the mounted state.

An electromotor7, preferably a synchronous geared motor or a stepped motor, is provided for mounting on an outer face of the floor of the shell1. Two hollow trunnions8, provided to take up the thread of screws9for fastening the electromotor7, extend from the floor of the shell1into its inner space. A shaft10of the motor engages through a central bore11of the shell1into its inner space. As shown inFIG. 1the shaft10is fitted with a slot12oriented obliquely to the axis.

A control body13, provided for mounting in the interior of the shell1, has a form similar to that of a wheel, with a wheel disc15stiffened by spokes14and a peripheral surface16enclosing the wheel disc15. The peripheral surface16is circular on its front side, as evident inFIG. 1; towards the rear it is formed as a cam disk, with two sections17,18of differing radius, which extend in each case over approximately half the periphery of the control body13. At the same time the radii of the sections17,18are selected such that at least the section17with the greater radius, when it lies before the key button5, presses its stylus6in and thus holds an electrical contact of the key button5open (or closed), which is closed (or open) is when the section18with the lesser radius is opposite the key button5.

Formed on the inside of the wheel disc15facing the floor of the shell1(see alsoFIG. 4) are a central support19, a shaft20shown inFIG. 5in enlarged plan view and a leg21. The support19is provided to take up the shaft10of the electromotor7positively and non-positively. Formed laterally in the support19is a slot22, which, when the shaft10is guided correctly into the support19, lies in a plane with its slot12. The shaft20and the leg21serve as mounting for a locking element23(seeFIG. 1,2) in the form of an L-shaped bent flexible wire, as shown inFIG. 9. The position of the support19, the shaft20, the leg21and the locking element23are evident in particular inFIG. 6, which shows a partially cut-away plan view of the inventive assembly. A shorter leg23A of this locking element23is inserted into the bore24of the shaft20; its longer section, which is longer leg23B, runs through a channel25at the free end of the shaft20and is held by a projection26formed on the shaft20under flexural loading, which holds the longer leg23B inserted in the slots12,22. The free end23C of the longer leg23B lies on the free edge of the leg21and crosses a hole27, formed in the wheel disc15. By introducing a tool through the hole27and shifting the longer leg23B of the locking element23downwards inFIG. 6, the longer leg23B can be pulled out of the slots12,22, and the control body13can be removed from the shell1.

In the configuration of the assembly shown inFIG. 6a window28of the control body13and the support4are covered congruently on the air passage opening of the shell1. The key button5lies opposite the peripheral surface16in the direct vicinity of a transition between the sections17,18. In order to close the air passage opening3, a drive circuit drives the electromotor7(not illustrated) connected to the key button5to a revolution in a fixed direction, until it recognises a change in the contact state of the key button5, from conductive to non-conductive or vice versa. Whenever this is the case, the control body13has performed a revolution of 180°, the air passage opening3is blocked, and the key button5is again located in the immediate vicinity of a transition between the sections17,18. To reopen the air passage opening3, it is also sufficient to drive the electromotor7until a change in the contact state of the key button5is detected.

A heating unit in the form of a resistance wire29is mounted on the outside of the shell1. It is fixed between a plurality of claws30, extending from the fore edge of the shell1outwards, and the tips of legs31formed on the peripheral surface of the shell1facing these claws30. The resistance wire30prevents freezing of incoming water drops between the peripheral surface16of the control body3and the opposite outer wall2of the shell1, which might lead to freezing solid of the control body13. Heating of other regions of the assembly is not necessary, and in any case there is still corporeal proximity adequate for freezing solid between mobile and non-mobile parts of the assembly, on which ice could build up, in the immediate vicinity of the shaft10. The shaft10is protected from moisture flowing down from above by the projecting support4and in particular by its cross-sectional form, which optionally deflects water drops present on it or the shell1in a lateral direction, away from the shaft10. Also, there is high torque of the motor7available in the immediate vicinity of the shaft10to break up a frozen-solid site. Because the motor7is attached in direct contact with the shell1, as shown inFIG. 7, if the motor is supplied with operating voltage by the drive circuit for a longer time, corresponding rotation of the control body can also be detected without the key button5and the motor again switched off, and the operating heat of the motor7results in a frozen-solid site in the region of the shaft10defrosting again and the control body can be rotated again.