EP0150020B1 - Interlocking gear for ventilating shafts or the like - Google Patents

Abstract

1. Closing device for ventilation ducts or the like, with at leat one movable closing member (19), which can be moved by means of an electrically operable adjusting device from its closed position into its open position and back again, which is located on the housing (13) of the closing device and comprises an adjusting member (26) mechanically connected to the at least one closing member (19), which adjusting member (26) can be heated electrically for changing shape, characterized in that the adjusting member (26) consists of a memory alloy and that the mechanical connection between the adjusting member (26) and the at least one closing member (19) in one of the two final shapes of the adjusting member (26), in which the at least one closing member (19) is located predetermined final position, is disengaged in the direction of movement of the adjusting member (26).

Description

The invention relates to a closure device for ventilation ducts or the like. According to the preamble of patent claim 1.

Under "ventilation ducts or the like." understood that there are ventilation ducts or other ventilation openings that serve to supply or remove supply air or exhaust air for ventilation purposes. Closure devices of this type are used to open and close the ventilation of building rooms or the like. Serving ventilation ducts or other ventilation openings, such as wall openings, window openings or the like, whereby it is generally customary to unite the ventilation duct or ventilation opening in question Assign fan that blows and sucks the supply or exhaust air through this ventilation duct or the like. The ventilation duct can therefore also be an air duct or air outlet of an air handling device, for example a wall or window vent.

Such closure devices usually have a plurality of mutually parallel closure slats as closure members, which can be adjusted together from their closed position to their open position and back. However, other closure elements can also be provided, for example a single rotary flap, slide or the like.

It is known to open the closure lamellae of such a closure device by means of an actuating device which has a bimetal leaf spring and an electrical heater acting thereon, an end region of the bimetal leaf spring being immovably connected to the housing of the closure device and its free end connected to the closure member or members or whose adjustment is mechanically coupled (DE-A 2322769). This closure device adjusts the closure element or elements silently and gently, is subject to practically no wear and tear and is inexpensive. However, in the wake of maintaining the heater, it adjusts the closure element (s) only very slowly if, for low energy consumption, the electric heater is designed to be as weak as possible, so that from the start of switching on the heater until it reaches the relevant end position (max . Open position or closed position) of the time elapsing or of the closure members - hereinafter called the switch-on delay time - is relatively long. Even then, the energy consumption of the electric heater is still relatively large. If the energy consumption of the electric heater is made larger in order to shorten the switch-on delay time, the bimetal leaf spring is heated to even higher temperatures and its transition to the cold position, in which the closure device is opened and closed depending on the design, then takes correspondingly longer, which is undesirable is. It has therefore been provided that the heating of the bimetallic leaf spring can be switched to strong and weak, such that the heating can be automatically set to strong when switched on and the switchover to weak heating takes place automatically when the bimetallic leaf spring at least almost bends to adjust the closure member has reached (DE-A 2353367). However, this switching device makes the switching device for the electric heater more expensive. In both cases, the adjustment of the closure element (s) that can be effected when the bimetal leaf spring cools due to its resulting change in shape runs very slowly, since this adjustment takes place over a relatively large temperature difference of the bimetal leaf spring of, for example, 80-180 K. The switch-off delay time is therefore particularly long with this bimetal leaf spring, which is desirable in some cases, but not in many cases. The switch-off delay time is understood to mean the period of time that elapses from the start of switching off the heating until the closure element or elements have reached their end position (closed position or maximum open position) that can be achieved by switching off the heating.

It is therefore an object of the invention to provide a closure device of the type mentioned above, the actuating device of which, while still structurally simple, is also able to open and close the closure member or members without any noise or almost noiselessly and is subject to practically no wear and tear, but with considerably less electrical energy for the heating can make do and also enables shorter switch-on and switch-off delays of the closure element or elements with little circuit complexity, whereby it should also be possible to ensure that the intended closed position and / or the intended maximum open position of the at least one closure element is still established even after a long operating time leaves.

To achieve this object, a closure device according to claim 1 is provided according to the invention. A second inventive solution to this problem is specified in claim 2.

According to claim 3, the measure according to claims 1 and 2 can also be used simultaneously.

It is known from JP-A 58214737 to provide a coil spring made of a memory alloy for the oscillating adjustment of motion-coupled air steering flaps of an air outlet of an air conditioning system for motor vehicles, in that one end of this coil spring is constantly supported on a stationary stop and the other end constantly rests on a straight guided slide, a helical spring serving as a return spring, which does not consist of a memory alloy, constantly pressing on the other side of this slide. The slide through penetrates a guide slot of a housing accommodating the two coil springs and lies in its two end positions on the ends of the guide slot, so that these two ends of the guide slot form stops for the slides which are permanently connected to the coil springs by movement.

With memory alloys, however, there is a risk that the final shape of the actuator will change due to the effect degradation. In the case of closure devices to which the invention relates, it can then occur that at least one closure member can no longer be completely moved into its closed position and / or into its maximum open position by the actuating member. In the case of such locking devices, however, it is important that at least one end position of the at least one locking element can be set in an operationally reliable manner even after a long operating time. In particular, it is important in many cases that the closed position of the at least one closure member is set securely so that the closure device can reliably close the ventilation duct or the like in question in the desired manner even after a long period of operation. In other cases or parallel to this, it can also be important that the achievable maximum open position of the at least one closure element does not change even after a long period of operation, in particular if the maximum open position is intended to ensure a certain minimum flow resistance of the at least one closure element which should not change in the course of the operating time.

The invention now makes it possible to prevent the effect degradation of the memory alloy of the actuating element from having an effect on at least one of the two end positions of the at least one closure element, or even to prevent the effect degradation of this memory alloy from occurring. This is explained in more detail below using the exemplary embodiments.

Memory alloys are known, see e.g. TAUTZENBERGER / STÖCKEL “Memory Effect and Technically Applicable Alloys”, Journal for Economic Manufacturing (ZwF) 78 (1983), 10, pp. 486-488. They have the property of taking a different shape at a higher temperature than at a lower temperature. As a memory alloy such. B. NiTi, Cu-Zn-AI or Cu-AI-Ni alloys in question. A Cu-Zn-Al alloy can preferably be provided since it is particularly inexpensive.

The temperature transition threshold of the memory alloy can be set specifically by varying the alloy composition, for example between -150 ° C and + 150 ° C. This temperature transition threshold is hereinafter called shape change temperature or shape change temperature range, the z. B. can be about 10 to 20 K. Provision can preferably be made for the shape change temperature or the shape change temperature range of the memory alloy for the actuator to be within a temperature zone of approximately 50-90 ° C., particularly expediently of approximately 65-85 ° C. The shape change temperature range can preferably be approximately 10 K and range from approximately 70-80 ° C. Taking the practical requirements into account, these temperature values are particularly favorable for low heating energy and for short switch-on and switch-off delays of the closure element or elements.

If, for example, the shape change temperature range extends from approx. 70 ° to approx. 80 °, this means that the closure element or elements at a temperature of the adjustment element of above approx. 80 ° C are in one end position, preferably the max. Open position, and at a temperature of the actuator below about 70 ° C in the other end position, preferably the closed position. This shape change temperature range is within the temperature zone of 60 to 85 ° C. indicated as preferred above. The term temperature zone denotes a temperature zone within which the shape change temperature or the shape change temperature range can lie, the respective shape change temperature range being smaller than the temperature zone in which it can suitably lie, or can correspond to it.

The actuator made of a memory alloy results in the closure devices according to the invention compared to a bimetal leaf spring, among other things. also the following advantages. Even if the electric heater only has a single heating power - i.e. it can only be switched on and off and, when switched on, always has the same electrical power consumption - short switch-on delays can be achieved, as is not the case with a bimetal leaf spring causing the same adjustment, at least with a single heating power are achievable. The switch-off delay times of the actuator made of a memory alloy according to the invention can be considerably shorter than that of a bimetallic leaf spring, since the actuator, due to the memory alloy, already has its "final shape" - hereinafter referred to as the cold final shape - which can be achieved by switching off the heating - in contrast to a bimetallic leaf spring reached at a relatively high intrinsic temperature, in the above example at approx. 70 ° C and not only at room temperature (approx. 20 ° C) like a bimetal leaf spring. The volume of the actuator and thus its heat capacity can advantageously be considerably smaller than that of the bimetallic leaf spring which has the same actuating path and the same actuating forces.

In general, it is more important to open the closure device quickly than to close it quickly. Since the heating of the control element can always take place faster than its cooling, it is advantageous to provide that the locking element or elements is opened and closed by switching on the electrical heating of the control element be closed again by switching them off.

In addition, the actuator consists of a memory alloy, among other things. The following further advantages: Surprisingly, because of the smaller volume, its costs can even be lower than that of a bimetallic leaf spring which has a comparable travel range and comparable actuating forces, so that the costs of the actuator can even be reduced relative to the costs for a bimetallic leaf spring. The electric heater also requires considerably less power consumption than the electric heater of a bimetallic leaf spring used for adjusting the same or the same locking members. The electrical energy consumption can thus be reduced by the invention and the costs of the electrical heating can also be reduced. Furthermore, one can manage with lower temperatures of the actuator achieved by the heating, which among other things. also has the advantage that the electrical heating of the actuator with heated adjacent parts made of plastic or the like can be made of less temperature-resistant material than in the case of a heated bimetal leaf spring. The relatively small space required by the actuator even in the case of a bimetallic leaf spring is further reduced considerably by the invention. The actuator made of a memory alloy also allows greater actuating forces with a smaller design than a bimetal leaf spring. The two final shapes of the actuator are also defined much more precisely than in the case of a bimetallic leaf spring, since the latter bends depending on the temperature over the entire intrinsic temperature range that occurs due to heating and non-heating, whereas the shape change of the actuator made of a memory alloy only the shape change temperature or in the shape change temperature range occurs, which in any case is significantly smaller than the temperature range to which the heated bimetal leaf spring must be exposed.

It can be provided that the actuator has the shape of a leaf spring, is preferably approximately straight in its one bending position and works in a two-way effect. This results in relatively large actuating forces with rapid adjustment of the closure element or elements. However, other designs of the actuating element can also be provided, for example as a rod, which can preferably be approximately straight in a bending position and acts according to the two-way effect, or the shape of a spiral spring curved in opposite directions in both bending positions or the like, which in particular according to the general Round effect can have. If particularly large adjustment paths of the actuator are desired, it can also have the shape of a helical or spiral spring or have a U-shaped or V-shaped shape. Other designs are also possible. The actuator can preferably be tongue-shaped. Memory alloys generally also have elastic properties. For this reason alone, the actuator, if it has the shape of a spring, can also be referred to as a spring, for example as a bending, leaf, screw, spiral spring or the like.

The electrical heating of the actuator can be carried out by a separate electrical heating device or its memory alloy itself can serve as a heating resistor. The electric heater can be arranged on the actuator. It then requires a particularly low heating output. It is sufficient here that memory alloys are metallic and therefore conduct heat quite well if they only extend over a relatively small part of the length of the actuator, preferably less than a quarter of the length of the actuator. This heater can be a PTC element, for example. H. an electrical resistor with a positive temperature coefficient, which reduces the electrical power consumption with increasing warming. Other training courses are also possible, e.g. those that have approximately constant electrical power consumption. For example, the heating can also be designed as an electrical heating development, as an electrical resistance layer or the like. Often it can also be expediently provided that the heater is not arranged on the actuator, but stationary on the housing of the closure device, preferably next to the actuator, so that it is then heated in particular by heat radiation and possibly also by convection from the heater.

The length of the actuator can be relatively small. If the closure device is provided with closure lamellae as closure elements, it can preferably be provided that the length of the actuating element is less than half the length of the closure lamella. This means that the space required for the actuator is particularly small and it can be accommodated particularly easily in the housing.

The actuating member can be supported on the housing of the closure device in order to exert its actuating force. A region of the actuator can be connected immovably to the housing in a particularly expedient manner.

• Fig. 1 eine Rückansicht einer Verschlusseinrichtung gemäss einem Ausführungsbeispiel der Erfindung, wobei an der Verschlusseinrichtung ein Axialventilator angeordnet ist,
• Fig. eine Draufsicht auf das Stellorgan der Verschlusseinrichtung nach Fig. 1,
• Fig.3 ein elektrisches Schaltbild der Verschlusseinrichtung mit Ventilator nach Fig. 1,
• Fig.4 eine gebrochene, ausschnittsweise und teilweise geschnittene Rückansicht einer Verschlusseinrichtung ohne Ventilator in geöffnetem Zustand, gemäss einem weiteren Ausführungsbeispiel der Erfindung,
• Fig. 5 die Verschlusseinrichtung nach Fig. 4, jedoch in ihrer Geschlossenstellung,
• Fig. 6 ein weiteres Schaltbild einer Verschlusseinrichtung gemäss einem Ausführungsbeispiel.

Exemplary embodiments of the invention are shown in the drawing. Show it:

• 1 is a rear view of a closure device according to an embodiment of the invention, an axial fan being arranged on the closure device,
• 1 shows a plan view of the actuator of the closure device according to FIG. 1,
• 3 shows an electrical circuit diagram of the closure device with fan according to FIG. 1,
• 4 shows a broken, partial and partially sectioned rear view of a closure device without a fan in the open state, according to a further exemplary embodiment of the invention,
• 5 shows the closure device according to FIG. 4, but in its closed position,
• 6 shows a further circuit diagram of a closure device according to an exemplary embodiment.

The closure device 10 with fan 11 shown in FIG. 1 can in practice also be referred to as a built-in wall fan with an integrated closure device. This combined ventilation device, designated as a whole by 12, has a housing 13 which has a circular pipe socket 14, at one end of which a front part which is approximately square in outline and which forms the closure device 10 is connected.

The axial fan 11 consisting of an electric motor 15 and an impeller 16 fastened to its rotor shaft is inserted in the pipe socket 14 which forms a ventilation duct for unheated supply air or exhaust air and which can be closed by means of the closure device 10. The motor 15 is held on the tube 14 by means of struts, not shown.

Subsequently, a rectangular, short passage 17 for the air conveyed by the fan 11 is let into the closure device 10, which forms an extension of the ventilation duct formed by the pipe socket 14. This passage 17 can be closed by five closure lamellae 19, which are pivotably mounted about parallel axes of rotation by means of pivots 20 which engage in bores of two opposite walls of the passage 17. A short arm 21, which projects vertically from it, is molded onto each closure lamella 19 and carries a driving pin 22 integral with it. These pins 22 are arranged parallel to the axes of rotation of the closure slats 19 and at a distance from their axes of rotation.

These pins 20 penetrate with plain bearing play bores of a straight coupling rod 23, which is arranged in a rear recess in the housing 13 and extends perpendicular to the axes of rotation of the closure slats 19. By moving the coupling rod 23 up and down, the locking slats 19 can be closed and opened synchronously. At the upper end of this coupling rod 23 engages a tension spring 24 forming a return spring, the upper end of which is suspended in an abutment on the housing 13 and which pulls the coupling rod 23 in the upward direction.

At the lower end of the coupling rod 23, which is injection molded from electrically insulating plastic, an arm 25, which struts vertically from it, is integrally molded on, which engages under a tongue-shaped actuating element 26 designed in the manner of a leaf spring, which pulls the coupling rod 23 out of the fully extended uppermost position, in which the Closure device 10 is closed, ie their closure slats 19 are in the closed positions shown, can be moved against the force of the return spring 24 into the bottom position shown in dash-dot lines, in which the closure slats 19 are in their intended maximum open positions. The pivoting angle of the closure slats 19 between the closed position and the maximum open position can be, for example, 75 to 85.

The actuator 26 in this embodiment consists of a rectangular, elongated, approximately straight metal strip of constant thickness in the fully extended position made of a memory alloy, the left end of which is held immovably in an electrically insulating, housing-fixed holder 27 with reference to FIG. 1 . The actuator 26 assumes two different shapes (bending states) in a two-way effect, depending on its temperature being above or below a shape change temperature or shape change temperature range determined by its memory alloy. These two different bending states are referred to below as the “cold final shape” and the “warm final shape”. The cold final shape is the fully drawn shape and the warm final shape is shown in broken lines. In the warm final shape, the actuating element 26 presses the coupling rod 23 into the lowest position, the actuating element 26 also being bent somewhat elastically in order to securely set this lowest position, in which the pins 22 rest against the housing-fixed stops determining the maximum open position of the closure slats 19 .

It should also be mentioned that the uppermost position of the coupling rod 23 shown is determined by the fact that the driving pins 22 also abut on stops fixed to the housing, the actuator 26 being able to be lifted somewhat from the arm 25 of the coupling rod 23, since the return spring 24 the coupling rod 23 pulls into this uppermost position. Due to the fact that the actuator 26 in its cold final shape is slightly raised from the arm 25, for example by a distance of 1-2 mm from it, this “play” of the mechanical connection between the actuator 26 and the locking slats 19 allows the cold final shape to change the actuator 26 by effect degradation, d. H. due to material fatigue without disadvantage.

FIG. 2 shows a top view of the actuating element 26 of the closure device 10 according to FIG. 1, this actuating element 26 being shown removed from this closure device 10.

The cold final shape of the actuator 26 can be, for example, below approximately 70 ° C. and the warm final shape above approximately 80 ° C. It is therefore sufficient to transfer the coupling rod 23 by means of this actuator 26 from the fully drawn position to the dash-dotted position to raise the temperature of the actuator 26 to over 80 ° C. When cooling again to below 70 ° C, the actuator 26 has then returned to its fully extended position, in which the return spring 24 has then pulled the coupling rod 23 up to the fully drawn position, in which the closure slats 19 are closed again.

A heating resistor 29, which here is a PTC resistor, is used to heat the actuator made of a memory alloy, which is placed approximately in the longitudinal center of the actuator 26 in metallic contact and on it by means of a short sleeve 30 made of electrically insulating material is held. The leaf spring-like elastic actuator 26 penetrates this sleeve 30. An electrical lead wire 31 is further soldered to the actuator 26 and another electrical lead wire 32 to the heating resistor. These two wires 31, 32 form the electrical connecting lines of the heating resistor, the actuator 26 also being connected to the Conducting the electrical heating current from the wire 31 to the heating resistor 29 takes part.

FIG. 3 shows a preferred circuit diagram of the device 12 according to FIG. 1. The electric motor 15 of the axial fan 11 and the heating resistor 29 are connected in parallel to one another and can be connected together to the electrical AC network 34 via a switch 33.

When the switch 33 is open, the electric motor 15 and the heating resistor 29 are switched off. It is then in the stationary state that the “cold final shape” of the actuator 26 and thus the closed position of the closure slats 19 are present. When the switch 33 is closed, the electric motor 15 starts immediately and the heating resistor 29 is heated and in turn heats the actuator 26. This actuator 26 is relatively short, as shown. E.g. its length can be 3 to 5 cm and preferably less than half the length of the closure slats 19. As a result, despite the heating resistor 29 contacting only a short central area of the control element 26, the control element, which has metallic and thus good thermal conductivity, is heated so quickly that it begins to move the coupling rod 23 downward within a few drops after switching on the heating resistor 29, and thus the Opening slats 19 to open. The full opening of these closure slats was achieved in a test model which had the design shown in FIG. 1 within about 10-15 seconds. This time can be kept even shorter by increasing the heating or extending the heating resistor 29.

When the heating resistor 29 is switched off again, the actuator 26 cools down again and the shape change temperature range is traversed in the downward direction again, so that the actuator 26, thanks to the two-way effect of its memory alloy, returns to the fully drawn position, in which the Sealing slats 19 are closed. In the case of the test model mentioned, the time from the start of switching off the heating resistor 29 to the complete closing of the closure slats was approximately 2-3 minutes. This time period can also be shorter or longer if desired. It can be extended, for example, by selecting a higher temperature for the actuator 26 when the heating resistor is switched on, or a lower temperature range, or by providing the actuator 26 with a heat-insulating coating or coating that slows down or cools it down. The delay time with which the closing slats 19 fully close after the heating resistor 29 is switched off can be shortened by weaker heating of the actuator 26 or by stationary arrangement of the electric heater at a distance from the actuator 26. In this exemplary embodiment, the thermal capacity of the heating resistor slows down 29 the cooling of the actuator 26, so that one can accelerate its cooling by arranging the heating resistor at a distance from the actuator 26. The actuating device having the actuating element 26, the heating resistor 29 and the coupling rod 23 for opening and closing the closure slats 19 is structurally simple, requires little space and is very reliable. It also opens and closes the closing slats 19 silently and gently. The energy requirement of the heater 29 is only low and it has short switch-on delay times and also relatively short switch-off delay times. It also has larger reserves of power with more defined start and end positions of the actuator 26 than a bimetallic leaf spring. The closure direction 10 'shown in detail in FIGS. 3 and 4 in rear view has an essentially square frame-like housing 13, in which a square air passage opening 17 is arranged, which can be opened and closed again by means of closure lamellae 19, which are as 35, the housing 13 rotatably mounted pivot pin 20 are rotatable about horizontal axes of rotation in the operating position and can be rotated by means of an adjusting device 48. For this purpose, driver pins 22 are fixedly arranged on these closure plates, such as 19, which engage in guide slots of an axially movable coupling rod 23 'which serves to rotate the closure plates, this coupling rod 23' in its uppermost axial position shown in FIG. 4 Locking slats 19 in their maximum open positions, which are determined by a housing-fixed, not shown stop for the coupling rod 23 'holds. In the operating position of this locking device 10 ', this coupling rod 23' is directed approximately vertically and is spring-loaded on the upper side by a compression spring 24 'serving as a return spring, which is supported on the uppermost frame wall 36 of the housing 13.

This coupling rod 23 'has a strip-like shape above an annular collar 37, and below the annular collar 37 it has a pin 39 which is circular in cross section and which projects into a bore in a coupling member 41 having a plate 40, which guides it with plain bearing play. This is based on one depression on the upper side of the plate 40 from a helical compression spring 42 on which the annular collar 37 of the coupling rod 23 'rests. This spring 42 forms a balancing spring for a reserve stroke of the coupling member 41 relative to the LAD ₅ pelstange 23 ', the purpose of which will be explained below. This compensating spring 42 is harder than the spring 24 _' , so that it is not yet fully compressed ₁₀ in the upper stop position of the coupling rod 23' according to FIG. 4.

In this exemplary embodiment, the actuator 26 forms a helix, ie its wire made of a memory alloy has a helical course. Instead of the ₁₅ shape of the adjusting member 26 as a cylindrical helical spring, it can also have other suitable shape which can cause the vertical lifting movements of the connecting rod 23 ', the shape is preferably a conical ₂₀ helical spring as conical spring, conical spring, double-cone spring, etc.

This actuator 26 is placed on a fixed piece on the lower bottom wall 43 of the housing 13, as shown, _{25 so} that a short pin 45 of this molded piece 44 projects into this actuator 26 with little radial play and this actuator 26 on one Ring collar 51 of this fitting 44 is seated on the housing 13 for axial support. _30th

The one-piece, rotationally symmetrical coupling member 41 has a circular annular collar 46 and a hollow pin 47 that struts downward from it, the latter protruding somewhat into the helix forming the actuator 26, as shown, ₃₅ with radial play, so that the longitudinal axis of the actuator 26 operates is always approximately aligned with the longitudinal axes of the coupling member 41 and the coupling rod 23 'which are aligned with one another. Wall ₄₀ at the lower floor 43 further includes two narrow rib-shaped holders 49 are arranged to hold a cylindrical tube 50th This tube 50 is held by these two holders 49 at a distance above the lower bottom wall 43 so that its 45 longitudinal axis is aligned with the longitudinal axes of the coupling member 41 and the coupling rod 23 '. The lower end face of this tube 50 is at the height or slightly below the height of the annular collar 51 of the fitting 44. The upper end face _{50 of} this tube 50 is located somewhat higher than the upper end of the actuator 26 in its extended, ie here its warm Final shape (FIG. 4), so that the actuator 26 for uniform heating is always inside the interior _{55 of} the tube 50. The plate 40 forms a closure which closes the tube 50 in the cold final shape of the actuator 26 on the top. This pipe 50 has, as shown, a practically over its length ER to ₆₀ stretching cylindrical, circular ring 52 is embedded in an electrical heating coil 29 _'of resistance wire, which is located near the inner wall surface of this thin ring 52nd If necessary. this heating coil 52 may be disposed adjacent or an electrically resistive layer be arranged as a heating on this inner wall surface at DIE ₆₅ ser inner wall surface of the ring. This ring 52 is made of elec- trically insulating material _5, for example. From ceramics, heat-resistant plastic or the like. In order to improve the heat insulating effect of this ring 52 is of yet it comprises a heat-insulating insulation 55, preferably a silicone rubber tube 10. This ring 50 comprises the actuator 26 as shown at a distance. The lead wires to the heating winding 29 'are not shown. This adjusting device 48 works as follows:

15 In the cold state, the actuator 26 has the shape shown in Fig., In which its turns practically abut each other. The plate 40 of the coupling member 41 then sits on the tube 50, the interior of which closes at the top, 20 with the annular collar 46 of this coupling member being at a short distance, for example 1-2 mm, above the actuator 26, so that there is axial play here between this collar 46 and the actuator 26 to compensate for tolerances and ₂₅ because of possible degradation of the actuator 26 is present. For this purpose, the pin 47 also grips into the helix, ie the actuator 26, with circumferential play. In this cold final shape of the adjusting member 26 are _30, the shutter blades 19 in their closed positions, which means that this closing device 10 is closed. '

To transfer the closure slats 19 into their open positions, the electric heating winding 29 'is switched on, ie supplied with current, and this now heats the actuator 26 practically uniformly and rapidly over its entire circumference both by heat radiation and by rapid heating of the ₄₀ the plate 40 closed interior 56 of the tube 50 air. As a result of the warming of this air, it tends to rise. However, initially it cannot yet escape ₄₅ from the pipe 50 because of the plate 40 in its closed position. The memory alloy of the actuator 26 has a two-way effect and can, for example, advantageously be a Zn-Cu-Al alloy. The Formänderungstemperaturbe- rich ₅₀ of the actuator 26 for the transition from the cold end shape in the warm end shape may be 65-85 ° C and for resetting from the warm end shape in the cold final shape preferably about 70-55 ° C, preferably approx. ₅₅ Of course, other shape change temperature ranges are also possible, depending on the memory alloy.

Since the heating of the actuating element 26 takes place very quickly after the heating winding 29 'has been switched on due to the interior 56 of the tube 50, which is still vertically upright, up to the opening of the plate 40, the plate 40 begins accordingly very quickly Turn on the ₆ 5 heating coil 29 'to open, and because of the shape Change temperature range is only relatively small, the heating winding 29 'causes rapid further change in shape of the actuator 26 even after opening the plate 40 and thus rapid transition to its warm final shape shown in Fig. 4, in which the closure slats 19 are open. To close the closure slats 19, the electrical heating winding 29 'is switched off. Since the plate 40 is still at a distance above the tube 50 in the shape shown in FIG. 4, the thermal upward flow (arrows 58) of this air in the tube 50 caused by the heating of the air in the interior of the tube 50 leads rapidly Cooling of the actuator 26 by inflowing cold, now no longer heated air from below into the tube 50. The result is that the temperature change range from the warm to the cold final shape of the actuating element 26 is passed through correspondingly quickly, and the actuating element 26 has reached its cold final shape after a short time, in which the closure device 10 is closed again.

The resilient axial relative adjustment possible by the compensating spring 42, i.e. Axial buffering, between the coupling rod 23 'and the coupling member 41 has the following purpose: First of all, it should be mentioned that the compensating spring 42 is always stronger in the presence of the warm final shape (FIG. 4) of the actuator 26 than in the presence of the cold final shape of the actuator (FIG 5) is compressed, in the latter case the size of the compression is determined by the warm final shape of the actuator 26 and the uppermost position of the coupling rod 23 'limited by a stop fixed to the housing.

In the case of particularly inexpensive memory alloys, such as, for example, Zn-Cu-Al alloys, an effect reduction can occur in the course of the operating time, i.e. that at least one of the two final shapes of the actuator 26 changes somewhat in the course of the operating time. This can lead to a lengthening or shortening of the warm and / or cold final shape of the actuator 26. The change in the warm final shape can be automatically compensated for by the compensating or buffer spring 42 in its effect on the adjustment of the coupling rod 23 '. If there is a shortening of the warm final shape of the actuator 26, the compensating spring 42 causes the coupling rod 23 'nevertheless to the uppermost position, which brings about the full open position of the closure slats 19, due to the changed warm final shape of the locking element 19, that is to say that it bears against the housing stop assigned to this position is pressed. The same thing takes place thanks to the compensating spring 42 if the warm final shape of the actuator 26 should lengthen (which should not normally occur), in this case then with a correspondingly stronger compression of the compensating spring 42 in the uppermost position of the coupling rod 23 '.

The above-mentioned axial effort between the collar 46 and the actuator 26 in its cold final shape can also serve to render the effect of the extension of the cold final shape of the actuator 26 ineffective on the closed position of the plate 40, so that this closed position when cold Final shape of the actuator 26 is always reached. The annular collar 46 of the coupling member 41 also has the task of forming a throttle member which throttles the thermal air flow through the tube 50 which takes place when the heating winding 29 'is switched on and the plate 40 is open, from bottom to top. The outer diameter of this collar 46 is matched to the inner diameter of the tube 50 so that when the heating is switched on, the warm final shape is always reliably maintained even when the plate 40 is fully open. By means of a suitable diameter of the annular collar 46, this can be achieved with minimal heating power of the electrical heating winding 29 '.

The actuator 26 is advantageously still in its warm final shape completely or essentially within the tube 50, so that it is not only washed by heated air, but also heated to its full length by the heat radiation caused by the heating of the tube 50 becomes what reduces the heating power required to maintain the warm final shape of the actuator 26.

• Das Stellorgan hat bei gegebenem Raumbedarf grösseres Arbeitsvermögen als bei Ausbildung in Gestalt einer Blattfeder. Auch die mit geringem Aufwand erreichbare gleichmässige Beheizung ist von Vorteil für die Funktion und Lebensdauer der Memory-Legierung. Der Raumbedarf ist sehr gering und die Herstellung des Stellorganes einfach. Es besteht ferner auch die Möglichkeit, die Wendel 26 nicht nur von aussen, sondern auch von ihrem Innenraum aus zu beheizen, indem bspw. dies durch einen in ihrem Innenraum angeordneten oder ihren Innenraum durchdringenden, stationären Heizstab bewirkt wird.

The formation of the actuator 26 in the form of a coil spring or helix also has the following advantages:

• The actuator has a larger work capacity for a given space than when training in the form of a leaf spring. Even heating that can be achieved with little effort is advantageous for the function and service life of the memory alloy. The space requirement is very small and the manufacture of the actuator is simple. There is also the possibility of heating the filament 26 not only from the outside, but also from the inside thereof, for example by means of a stationary heating element arranged in the inside or penetrating its inside.

There is also the possibility of heating the actuator 26 directly by electric current flowing through it, be it alone or in addition to a separate heater. In this case, memory alloy not only serves to change the shape of the actuator 26, but at the same time serves as a heating resistor that is used for heating itself. It is understood that in this case the electrical resistance of the memory alloy must be sufficiently large. Memory alloys suitable for this purpose can preferably be Ni-Ti alloys. FIG. 1 shows an electrical circuit diagram of this type, in which the control element 26 can be connected in series with an ohmic series resistor 53 via an on-off switch 33 to a current source 34 for its own heating, which serves to change the shape. In this case, the turns of the Stellor 5 in the cold final shape do not lie against one another.

Claims (21)

1. Closing device for ventilation ducts or the like, with at least one movable closing member (19), which can be moved by means of an electrically operable adjusting device from its closed position into its open position and back again, which is located on the housing (13) of the closing device and comprises an adjusting member (26) mechanically connected to the at least one closing member (19), which adjusting member (26) can be heated electrically for changing shape, characterised in that the adjusting member (26) consists of a memory alloy and that the mechanical connection between the adjusting member (26) and the at least one closing member (19) in one of the two final shapes of the adjusting member (26), in which the at least one closing member (19) is located in a predetermined final position, is disengaged in the direction of movement of the adjusting member (26).

2. Closing device for ventilation ducts or the like, with at least one movable closing member (19), which can be moved by means of an electrically operable adjusting device from its closed position into its open position and back again, which adjusting device is located on the housing (13) of the closing device and comprises an adjusting member (26) mechanically connected to the at least one closing member (19), which can be heated electrically for changing shape, characterised in that the adjusting member (26) consists of a memory alloy and that the mechanical connection between the at least one closing member (19) and the adjusting member (26) comprises a resilient buffer (42), which serves for compensating for deformations at least of one final shape of the adjusting member occurring due to a reduction of effect.

3. Closing device according to Claim 1, characterised in that the mechanical connection between the at least one closing member (19) and the adjusting member (26) comprises a resilient buffer (42), which serves for compensating for deformations in the other final shape of the adjusting member occurring due to a reduction of effect.

4. Closing device according to Claim 1 or 3, characterised in that the final shape of the adjusting member (26), in which the mechanical connection between the adjusting member (26) and the at least one closing member (19) is disengaged in the direction of movement of the adjusting member (26), is its cold final shape, the at least one closing member (19) in this cold final shape of the adjusting member (26), preferably being located in its closed position.

5. Closing device according to one of the preceding Claims, characterised in that it is part of a fan (12), the heating system (29) of the adjusting member (26) preferably being connected electrically in parallel with the drive (11) of the fan.

6. Closing device according to one of the preceding Claims, characterised in that the adjusting member (26) is spring-loaded by a restoring spring (24; 24') in the direction of its one final position, preferably in the direction of its final shape adopted when the heating system is switched off until reaching this final shape or until shortly before reaching this final shape.

7. Closing device according to one of the preceding Claims, characterised in that the adjusting member (26) is in the form of a leaf spring, whereof one final shape is preferably substantially straight.

8. Closing device according to one of the preceding Claims, characterised in that the adjusting member (26) consists of a strip or wire, whereof one end region is mechanically connected to the closing member or members (19) for its or their displacement, the mechanical connection preferably comprising a connecting rod (23; 23').

9. Closing device according to one of the preceding Claims, characterised in that one region, preferably an end region of the adjusting member (26) is fixed to the housing of the closing device.

10. Closing device according to one of the preceding Claims, characterised in that the adjusting member (26) is constructed in the form of a rod.

11. Closing device according to one of Claims 1 to 9, characterised in that the adjusting member (26) is in the form of a helical spring.

12. Closing device according to Claim 11, characterised in that the helical spring is a cylindrical or conical helical spring.

13. Closing device according to one of the preceding Claims, characterised in that an electrical heating system (29) serving for heating the adjusting member (26) is located on the adjusting member (26) and/or that the heated state of the adjusting member (26) serves_' for opening and keeping open the closing member or members (19).

14. Closing device with closing vanes as closing members, according to one of the preceding Claims, characterised in that the length of the adjusting member (26) is less than half the length of the closing vane (19).

15. Closing device according to one of the preceding Claims, characterised in that the adjusting member (26) operates according to the two-way effect or the all-round effect.

16. Closing device according to one of the preceding Claims, characterised in that the deformation temperature or the deformation temperature region of the adjusting member (26) lies within a temperature range of approximately 50-90°C, preferably of approximately 65-85°C.

17. Closing device according to one of the preceding Claims, characterised in that the adjusting member (26) consists of a Cu-Zn-Al-alloy or an NiTi-alloy or a Cu-AI-Ni-alloy.

18. Closing device according to one of the preceding Claims, characterised in that the adjusting member (26) is located in the interior of a tube (50) arranged in a stationary manner on the housing (13), preferably with all-round clearance from this tube.

19. Closing device according to Claim 18, characterised in that the electrical heating system (29') associated with the adjusting member is located on or in the tube wall and/or is surrounded by the adjusting member and/or that the mechanical connection (23', 42, 40) between the adjusting member (26) and the at least one closing member (19) comprises a stopper (40), which in one final shape of the adjusting member (26) preferably in its cold final shape, closes off one end face of the tube (50).

20. Closing device according to Claim 19, characterised in that in the operating position of the closing device, the tube (50) is arranged upright and its upper opening can be closed by the stopper (40) and that the lower end face of the tube is permanently at least partly open and/or that at least one permanently open air passage is provided in the tube wall on or close to this lower end face.

21. Closing device according to one of the preceding Claims, characterised in that the adjusting member can be heated exclusively or additionally due to the fact that it forms an electrical resistor serving for its own heating, which resistor can be connected to a current source.

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