Patent Grant
10886085
This application claims priority from German Application No. 10 2018 203 099.5, filed Mar. 1, 2018, the contents of which are hereby incorporated herein in its entirety by reference.
The invention relates to a temperature-controlled device for switching off a heating device at a limit temperature, wherein the device has manual reactivation means as a type of reset, or for re-switching on after switching off.
A device of this type in a simple form as a limiter for being able to switch off a heating device at a limit temperature is known from DE 2246177 A1. Said switching off in the first aspect is then intended to be permanent in such a manner that no automatic re-switching on is performed when the temperature drops below the limit temperature. This thus serves for enhancing the safety of an operation of the heating device and not for regulating to a specific temperature which is to be adhered to as precisely as possible.
However, in order for the heating device in this instance to be able to continue to be operated, in the case of a refinement it is possible for an operator to push a button, or to generally move or activate a handle, so as to enable the re-switching on of the switching means, or the continuing operation of the heating device, respectively. This in mechanical or thermo-mechanical terms, respectively, quasi corresponds to the electric behavior of an electrical circuit-breaker which after having been tripped can be manually closed again by throwing a lever.
The invention is based on the object of achieving a temperature-controlled device mentioned at the outset, by way of which issues of the prior art can be solved and it is in particular possible for the reactivation means for reactivating, or re-switching on, respectively, once more the switching means to be embodied in a practicable and at the same time reliable manner.
Said object is achieved by a temperature-controlled device having the features of claim 1. Advantageous and preferred design embodiments of the invention are the subject matter of the further claims and will be explained in more detail hereunder. The wording of the claims by way of explicit reference is incorporated in the content of the description.
The temperature-controlled device has a thermo-mechanical temperature sensor device, a switch-off device, and manual reactivation means. The temperature sensor device has a thermo-mechanical temperature sensor such as is known above all from the prior art, and a trigger. The thermo-mechanical temperature sensor can be rod-shaped from elements having dissimilar coefficients of expansion, or be a hydraulic system having a line which has liquid or oil, respectively, having a specific coefficient of temperature pertaining to the expansion or volume, respectively. A specific expansion of the thermo-mechanical temperature sensor is performed as a function of a temperature detected, said specific expansion acting on the trigger. The trigger can then, specifically directly or indirectly, activate and switch switching means which are provided in the switch-off device. The heating device can thus be switched off at the limit temperature, wherein the limit temperature can be set by an operator as a settable temperature limit. Alternatively, said limit temperature can advantageously be predefined ex-works. The switching means are furthermore configured for installation, or incorporation, respectively, in the path of an energy supply to the heating device, and in practice are contained, conjointly with the device, in the energy supply to said heating device such that said switching means can now switch off the heating device, or can separate said heating device from the energy supply, respectively, when the limit temperature is reached.
The manual reactivation means have a movable handle for transmitting a force, a so-called operating force, of an operator, so as to be able to reactivate or re-switch on, respectively, the switching means after the switching-off of the heating device by the trigger. As has been mentioned at the outset, an operator, when present and upon identifying the switching-off of the heating device, should thus have the possibility of being able to perform a brief check of the state of the heating device, or of an apparatus comprising the heating device. In the absence of any obvious serious fault, the operator by way of the movable handle, or by moving or depressing the handle, respectively, can reactivate or re-switch on, respectively, the switching means such that the heating device can again heat. Transmission means between the handle and the switching means which are connected in a force-transmitting manner to the handle are furthermore provided. The handle acts in particular by way of the transmission means on the switching means.
It is provided according to the invention that the transmission means have a click spring which in the line of an operating force that acts thereon from the handle, up to a certain or predefined limit force, is in a basic position which is or forms a first position. This means that the click spring is in direct prolongation of the operating force, which runs in a direction through the click spring, or that the operating force directly acts upon the click spring.
When the operating force acting on said click spring exceeds the limit force, or is larger than said limit force, respectively, the click spring clicks from the basic position to a deflected position which is a second position of the click spring. The click spring preferably has only these two positions, thus at all times attempts to return from the deflected position back to the basic position, such that said click spring is quasi monostable. The restoring force by way of which the click spring attempts to return from the deflected position back to the basic position herein can be lower than the limit force which is required for pushing the click spring from the basic position to the deflected position, thus for making the click spring click. The limit force is advantageously greater by 20% to 500%, particularly advantageously greater by 75% to 200%, than the restoring force.
The click spring in the basic position reactivates the switching means, or re-switches on said switching means, respectively, or enables said switching means to be re-switched on. This is performed above all by way of a direct force transmission. The click spring in the deflected position releases so much movement path on the transmission means for the switching means that the switching means by the temperature sensor device and by the switch-off device at a temperature above the limit temperature are activatable and can again be switched by the trigger. Renewed switching-off of the heating device can be performed on account thereof. It can in particular be achieved that the transmission means for such switching-off of the heating device do not block or prevent switching even in the case of a depressed handle. To this end, it can be advantageously provided that a type of path limiter or detent is provided on the handle in such a manner that the handle therefor by way of detent means can only be moved relative to the device for a maximum movement path. This can be a compression detent which acts in particular against the housing of the device or against an aperture behind which the housing of the device can be assembled. Detent means of this type can be configured, for example, so as to be sleeve-like or in the manner of protrusions, and proceed from the handle towards the housing of the device, wherein said detent means can at least partially engage across the transmission means.
It is thus possible that any malfunction in which an operator by means of the handle reactivates or re-switches on, respectively, the switching means, and by way of permanently activating or depressing the handle then applies so much operating force that the trigger cannot overcome said operating force by way of a trigger force is prevented. Switching-off by way of the temperature sensor device would then no longer be possible, and a substantial safety function would be put out of operation. The click spring in the transmission means between the handle and the switching means can prevent this, in particular when the own limit force of said click spring for clicking lies below the trigger force. In the instance when the handle has been activated or depressed, respectively, by the operator, the transmission means can no longer block the switching of the switching device, or above all the switching-off by the trigger, respectively.
In an advantageous design embodiment of the invention the click spring can be configured so as to be planar and curved. Said click spring is advantageously curved in one direction, particularly advantageously uniformly curved, for example having a curvature height which is between 3% and 25% of the maximum or minimum diameter. Click springs of this type are in principle known to a person skilled in the art, for example also as a so-called clicker. Alternatively, a click spring can also be configured so as to be in an elongate shape, for example having one or two spring legs.
A click spring can particularly advantageously be composed of sheet metal, in particular suitable spring steel. The diameter of a planar click spring can be between 1 cm and 4 cm; a thickness can be between 0.01 mm and 1 mm.
The transmission means can be configured such that said transmission means have a pressure arm and a rocker. The rocker in turn has a bearing point about which said rocker can be pivoted. Said bearing point is advantageously disposed so as to be eccentric. The pressure arm is movably configured and fastened, said pressure arm in particular being movable or pivotable about a bearing at one end. The fastening of the pressure arm should advantageously be such that the handle by way of the operating force acts on said pressure arm so as to move the latter. The pressure arm, in particular by way of a free end which is opposite to the other end fastened to the device, can then push against the rocker on a first side of the bearing point of said rocker, when the device is to be reactivated, or the switching means are to be switched on again, respectively. The rocker on another, second side of the bearing point, by way of the movement of said rocker, or by the pivoting, respectively, then releases a movement path for the switching means such that the switching means can close again, this advantageously being performed in a self-acting manner as soon as the movement path has been released. The device can then enable the continuing operation of the heating device or the renewed operation of the heating device until the temperature sensor device, upon again reaching the limit temperature, again switches off the switching means by way of the trigger.
The rocker mentioned is advantageously configured so as to be bistable. Said rocker has a free position as a first position in which the switching means are not activated, or are not influenced by the rocker, respectively. There is advantageously no direct contact. By contrast, the switching means in a second position as a blocking position of the rocker are forcibly opened by the rocker such that the rocker keeps the switching means opened. This may be performed counter to a spring force mentioned, or a closing force of the switching means. The switching means advantageously have a sprung arm having a contact head which, on account of a spring force formed by said contact head itself, pushes against a counter contact when the switching means are closed. The contact head, counter to the spring force thereof, is pushed away from said counter contact when the rocker quasi forcibly opens the switching means.
The bistable configuration of the rocker can advantageously be achieved in that, in a manner known per se, a rocker spring bears on the rocker. The rocker is thus mounted in a quasi bistable manner having the two afore-mentioned positions between which said rocker, by virtue of the rocker spring bearing thereon, abruptly clicks. The rocker spring herein advantageously bears against the second side, or on the second side, respectively, of the rocker. A transition point up to which the rocker is in the first free position can be configured, and said rocker clicking to the second blocking position when said rocker has been moved beyond said transition point. This also progresses in the same manner in the opposite direction. Moving or triggering, respectively, of the rocker is advantageously either performed by the pressure arm, specifically preferably in the direction from the blocking position to the free position. The movement in the opposite direction is particularly advantageously caused by the trigger which in this instance acts on the other side of the bearing point of the rocker as the pressure arm, and moves the rocker from the free-position to the blocking position. The trigger can thus cause the opening, or the switching-off, respectively, of the switching means by the rocker.
The trigger can act directly on the rocker; in particular, said trigger can push said rocker from the free position to the blocking position, as has been described above. However, for a movement that is capable of improved control, a trigger lever on which the trigger acts in such a manner that an increasing deflection of the trigger lever is caused by the trigger as the temperature increases at the temperature sensor can also be provided. The trigger lever can above all be disposed between the trigger and the switching means. Said trigger lever can also cause a certain positive gearing of the path of the trigger with a view to a longer path, and alternatively a negative gearing with a view to a shorter path having a higher force. In a further advantageous design embodiment of the invention it is possible for the trigger lever to also be disposed between the trigger and the afore-mentioned rocker.
The bistable design embodiment of the rocker by way of triggering the switching means while activating the switching means has the advantage that the abrupt clicking of the rocker from the free position to the blocking position abruptly activates or opens, respectively, the switching means, in particular in the afore-described configuration. No sparking or contact fire can thus arise. This, however, is known per se from devices of this type for delimitation.
When, as has been described above, both the pressure arm, on which the operating force from the handle can act, as well as the trigger, by way of the triggering force exerted thereby, act on the rocker, it can be provided that a force path having a force transmission exists between the trigger and the handle. The click spring according to the invention can in this instance be disposed in said force path, or in said force transmission of the transmission means, respectively. Said force path, or the force transmission, respectively, can be directly form-fitting, with the exception of the click spring, or the movement path thereof between the basic position and the deflected position, respectively. This should apply at least when the afore-mentioned rocker is in the free position and the handle is activated in such a manner that the afore-mentioned pressure arm pushes against the rocker and the click spring is however still in the basic position.
The click spring is preferably configured in such a manner that the afore-mentioned limit force is less than the triggering force which has been generated by the trigger at a temperature increase, advantageously at a temperature increase beyond the limit temperature, in particular when the trigger by virtue of the temperature increase has traveled a path between 0.5 mm and 3 mm, in particular approximately 1 mm. It can thus be provided, for example, that the trigger has a force generation between 20 N/mm and 60 N/mm. A limit force in this instance can be approximately 50 N. This means that when the click spring is in the basic position, an operator by way of approx. 50 N as the operating force pushes onto the handle and thus against the click spring and the pressure arm, wherein said force pushes onto the first side of the afore-mentioned rocker. The trigger pushes against the second side of the rocker, specifically at an increasing force at an increasing temperature. As soon as the limit force on the click spring has been exceeded, for example at the afore-mentioned 50 N, the click spring clicks on account of being pushed by the trigger, and releases a specific additional path, specifically the path or the path differential by way of which said click spring has clicked. Said path differential between the basic position and the deflected position of the click spring can be so large that the rocker by the trigger is moved such that said rocker switches off the switching means. When an operator continues to keep the handle depressed while applying the operating force or else an even higher force, it is precisely advantageously provided herein that the afore-mentioned detent means for the handle prevent that the operator quasi pushes the handle onwards also further by the mentioned path differential by way of an operating force which exceeds the triggering force exerted at this point in time by the trigger. By way of an exact configuration, or adjustment, respectively, of the detent means it can be achieved precisely that the rocker is moved, in particular is moved beyond the transition point thereof, and thus opens the switching means again.
While the rocker is advantageously configured so as to be bistable in such a manner that said rocker after clicking is stable in each of the two positions, thus in the free position and in the blocking position, such that said rocker can in each case be moved to the other position only by an external force acting thereon, the click spring should be configured in such a manner that said click spring is stable only in the basic position. This means, that said click spring clicks back on its own or when an operating force of the handle is absent from the deflection position, respectively, in a self-acting manner to the basic position. In this case, said click spring can push by way of restoring force. Said click spring, in the case of an afore-mentioned blocking of the trigger, on the one hand, and the handle, on the other hand, can in this instance quasi again release the path differential mentioned. Said click spring in this instance is configured so as to be monostable.
In a design embodiment of the invention, the pressure arm can have a main body which is configured for the force transmission of the operating force, in particular to the mentioned rocker. Said force transmission is advantageously a compressive force, such that the pressure arm can be precisely configured specifically for transmitting a pressure force. To this end, said pressure arm can be provided with embossed features or the like, and/or a sufficient material thickness. A mounting of the pressure arm in the device can be resilient, and does not have to be performed about a rotary bearing, knife-edge bearing, or the like.
The pressure arm, or the main body thereof, respectively, is advantageously configured as a double bridge having two longitudinal arms which both extend in a rectilinear manner from a mounting, or fastening, respectively, at one end of the pressure arm at which said longitudinal arms are connected in a planar manner to the device, or extend in the longitudinal direction thereof, respectively. The longitudinal arms have at least one transverse arm which connects said longitudinal arms to one another. Said transverse arm can also be so wide that said transverse arm forms a type of transverse face or central face. Two transverse arms can advantageously connect the two longitudinal arms to one another, wherein a spacing of said transverse arms is of such type that a free intermediate space is formed between said transverse arms. The click spring can be fastened to or by way of said intermediate space, or be connected to the main body in such a manner that said click spring is fixedly disposed on said intermediate space, respectively. Said click spring can be to the main body connected in a form-fitting or materially integral manner, said click spring preferably being welded to the latter. The click spring in the deflected position can in this instance optionally engage in the intermediate space.
A mentioned path differential between the basic position and the deflected position can be between 0.5 mm and 4 mm, advantageously between 1 mm and 3 mm.
A bend on the main body, or on the longitudinal arms, respectively, can be provided behind a second transverse arm, or behind the click spring, respectively. Said bend can be between 70° and 110°, advantageously between 80° and 100°. That part of the main body that lies behind said bend can point approximately towards the afore-mentioned rocker, this being considered to be very advantageous for the transmission of a compressive force.
Alternatively, the click spring can also be integrated directly in the transmission means, or in the main body, respectively, such that said click spring is configured in one part and so as to be integral therewith. The main body, conjointly with the click spring, can thus be configured from a sheet metal by a production procedure, wherein the click spring as a curved face can be produced by embossing, for example. In this instance it is considered very advantageous for that region of the main body that is contiguous to the region having the click spring or the click effect, respectively, to be configured in a stable manner, in particular by way of an increased material thickness, material doubling, or bending or folding.
In an advantageous design embodiment of the invention the handle can act directly against the click spring on the transmission means and bear on the latter. Said handle can bear on said click spring, above all when a click spring is configured so as to be planar and curved as described above, so as to be advantageously approximately centric. To this end, a corresponding tappet or the like which can be connected to the handle can be provided.
In a further design embodiment of the invention it can yet be provided for the trigger lever that said trigger lever by way of a spring is at all times pushed against the trigger. Alternatively, said trigger lever, by way of the configuration or fastening, or mounting thereof, respectively, can push in a self-acting manner against the trigger. Any slack which could potentially disturb the mentioned rocker or adversely affect the latter can thus be prevented.
These and further features will emerge not only from the claims but also from the description and from the drawings, wherein the individual features may be realized in each case individually or severally in the form of sub-combinations in an embodiment of the invention and in other fields, and may constitute advantageous and independently protectable embodiments for which protection is claimed here. The division of the application into individual sub-sections and sub-headings does not restrict the statements made here in terms of their general applicability.
Exemplary embodiments of the invention are schematically illustrated in the drawings and will be explained in more detail hereunder. In the drawings:
A deep fryer 11 as an appliance, or an electrical appliance, respectively, as has been described at the outset is illustrated in
The afore-mentioned switch-off device 31 per se is composed mainly of switching means 38 in the form of an elongate and elastic switch spring 39 which is fastened at the right end thereof. Said switch spring 39 is advantageously also electrically contacted at said right end. The switch spring 39 at the left free end supports a contact head 40 by way of which said switch spring 39, on account of the pretensioning thereof, bears so as to push on a counter contact head 41 and closes the contact or the switching means 38, respectively. Since the switching means 38 here are very simple, but a switching procedure by way of the spring-elastic switch spring 39 is to be performed rapidly or abruptly, respectively, a transmission pin 37 is mounted so as to be longitudinally movable in the housing 21, on the one hand. Said transmission pin 37 bears on the switch spring 39 and in some circumstances can also be fastened thereto. The switching means 38 can be opened by means of said transmission pin 37. To this end, the switch-off device 31 has a rocker 33 which by means of a rocker rotation point 36 is mounted in the housing 21, wherein the mounting can be a so-called knife-edge mounting which is known per se. A left rocker arm 33a protrudes beyond the transmission pin 37. A rocker spring 35 which is flexed upwards under compressive stress is brought to bear against the end side of said rocker arm 33a that points to the left, said end side being notched. Said rocker spring 35 by way of the left end thereof is supported on a mount in the housing 21.
A right rocker arm 33b of the rocker 33 is significantly shorter and supports an adjustment screw 34 screwed thereinto. The deflection of the rocker 33 in the position illustrated here, but above all also the activation thereof according to
Rockers 33 of this type, or the entire switch-off device 31, respectively, for this purpose are also known from the prior art. The rocker 33 is obviously configured so as to be bistable. Said rocker 33 in the free position as a first position illustrated in
In order for this movement of the rocker 33 now to be caused, a trigger lever 64 which at the left end thereof is pivotally mounted, for example also by way of an afore-mentioned knife-edge mounting, is provided between the rocker 33 and the diaphragm box 28. A downwards-pointing trigger protrusion 65, for example as a tab bent out in a downwards manner, is provided in the trigger lever 64. This trigger protrusion 65 in a movement of the trigger lever 64, or in the downwards pivoting of said trigger lever 64, respectively, pushes on the rocker 33, as described above. To this end reference is also made to
The trigger lever 64 at the right end has in elongate and screw-fittable trigger detent 67. By way of the latter it can optionally be set how far the trigger lever 64 strikes from below on a part of the housing 21 where the afore-mentioned adjustment screw 34 can also impact in a downwards manner. The trigger lever 64, for example by way of a spring (not illustrated here), can furthermore be pulled upwards, or pivoted in a counter-clockwise manner, respectively, in such a manner that said trigger lever 64 at all times bears on the pressure protrusion 29 of the diaphragm box 28. Said trigger lever 64 can thus not push downwards against the rocker 33 in a self-acting manner and cannot undesirably influence said rocker 33.
When the temperature in the fry pot 13 in the operation of the deep fryer 11 now rises, and the frying fat situated in the interior 14 of said fry pot 13 potentially reaches an excessive temperature, which can become very dangerous for reasons of spontaneous combustion, the temperature sensor device 22 intervenes. The expansion fluid in the sensor 25 and in the pipeline 26 expands specifically by virtue of the increasing temperature and herein in a known manner causes a downwards expansion of the diaphragm box 28 (i.e., the trigger). The pressure protrusion 29 pushes the trigger lever 64 downwards, or pivots the latter in the clockwise manner, respectively. At a specific point herein the trigger protrusion 65 comes to bear on the rocker 33 and pushes said rocker 33 downwards as the diaphragm box 28 increasingly expands. When a transition point as has been previously described of the bistable rocker 33 is exceeded herein, said rocker 33 clicks from the free position to the blocking position which is precisely illustrated in
Since the heating device 16 is now switched off, the temperature in the fry pot 13 drops again, this being registered by the temperature sensor device 22. The expansion fluid increasingly contracts, the diaphragm box 28 consequently also being increasingly contracted towards the top. This can be seen in
However, the rocker 33, by virtue of the bistable design embodiment thereof, remains so as to be pushed downwards in the blocking position according to
The operator for renewed switching-on of the heating can now activate reactivation means 44 and to this end push a pushbutton 46 (i.e., a movable handle), as is visualized in
As can be seen from the comparison of
The pressure arm 52 at the left end has a spring region 54. The spring region 54 pushes the pressure arm 52 upwards, or causes a rotation in a counter-clockwise manner, respectively. This is achieved by the inherent material elasticity; the pressure arm 52 is advantageously composed of spring-elastic sheet metal.
It can be seen from
As is, a purposeful and safe state could have now been re-established, and the deep fryer 11 could continue to safely operate again, respectively. However, a look at
As can be seen from
In this downwards clicking of the click spring 57 a path of approximately 1 mm to at most 4 mm is traveled as soon as the click spring 57 after exceeding the transition point thereof clicks downwards to the deflected position. The diaphragm box 28 can now continue to expand, or by way of the pressure protrusion 29 move downwards without having to be pushed counter to a strong force. The click spring 57, configured so as to be monostable, by way of the restoring force thereof does indeed attempt once more to return to the original shape thereof according to
The restoring force of the click spring 57 can even be so minor that said restoring force, in the case of the chosen lever ratios and the design embodiment of the rocker spring 35, is not sufficient for the right rocker arm 33b to be pushed downwards counter to the force of the rocker spring 35. The rocker 33, after the left rocker arm 33a has been pushed downwards by the trigger protrusion 65 of the trigger lever 64 by virtue of the expansion of the diaphragm box 28, thus remains in the position according to
As can also be seen from
It is only when an operator releases the pushbutton 46 that the latter can jump out to the position illustrated in dashed lines, specifically because the monostable click spring 57, by way of a central region 58 on which the lower side of the tappet 50 bears, then jumps upwards in a self-acting manner. The state of
The click spring 57 on the pressure arm 52 can be better seen in
The click spring 57 is placed on top of the main body 56, or is fastened thereabove. The click spring 57 has a curved central region 58 and four peripheral concavities 60a to 60d which therebetween have in each case one bearing foot 62a to 62d. The click spring 57 by means of said bearing feet 62a to 62d is fastened, advantageously welded, to the pressure arm 52 in the region of the main body 56.
The side views of
When a force F as aforementioned operating force, illustrated in
A modification of a pressure arm 152 which also has two pressure arm ends 153a and 153b which point downwards towards the right and which are brought together in a main body 156 is illustrated in
The design embodiment of such an integration of the pressure arm 152 and the click spring 157 in terms of construction and production is not that simple, but has the great advantage of greater integration. The welding of the click spring 57 to the main body 56, or to the pressure arm 52, respectively, according to
The object of a permanent blockage of the switching-off of the heating device 16 in the deep fryer 11, potentially desired by an operator, being suppressed even when the pushbutton 46 for reactivating the switching means 38 is permanently depressed, or is held up to the detent, respectively, can thus be achieved by way of the invention. Appliance safety is thus maintained at all times.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2018 203 099 | Mar 2018 | DE | national |
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|---|---|---|
| 1915583 | May 1965 | DE |
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| European Patent Office, Search Report for European Patent Application No. 19154600.1, dated Jul. 8, 2019, 8 pages, Munchen, Germany. |
| Number | Date | Country | |
|---|---|---|---|
| 20190272964 A1 | Sep 2019 | US |
