Abstract:
A safety and/or control device for an electric cooking appliance, the appliance having a case defining a cooking enclosure and a component for heating the enclosure. The device includes: at least one switch arranged to close a circuit for supplying current to the heating component, this switch including a case and an actuating button, at least one sensing element which is movable between a safe position, corresponding to a predetermined configuration for placing the appliance into operation, and an unsafe position, corresponding to another configuration in which the appliance should not be placed into operation, and, optionally, a control unit accessible from outside the case and movable between an on position and an off position. The switch can be operated to close the current supply circuit in response to the sensing element and the control unit, or in response to two sensing elements, when the element and the control unit or both sensing elements are each in a defined position. Alternatively, the sensing element can have a transmission element which cooperates with the switch to close the current supply circuit in response to any of the conditions mentioned above.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to the general technical field of electric cooking appliances of the type having a cooking enclosure as well as a movable or removable element, such as for example a removable bowl, a lid, or even a door, and heating means. The present invention is more particularly, but not exclusively, directed to electric fryers. The invention concerns specifically safety and/or control devices for such appliances. 
     It is known to manufacture electric fryers with a removable bowl in which the heating means are mounted at the bottom of a case provided to receive the removable bowl. In order to prevent such an appliance from operating in the absence of a bowl or in the presence of an incorrectly positioned bowl, it is known to equip the appliance with a device for detecting the presence of the bowl, this device including a switch provided to interrupt the supply of current to the heating means if the bowl is not present, or is not correctly positioned, in the case. It is also known to provide electric cooking appliances with a main on-off switch. 
     The patent document GB 2 222 025 discloses a safety and/or control device for an electric appliance, the appliance having an enclosure associated with heating means mounted in a removable manner on a current supply base. The safety and/or control device includes at least one switch arranged to close the supply circuit of the heating means, this switch including a case and an actuating button, or actuator, a sensing element movable between a first, heating, position and a second, off, position, and a control means accessible from outside of the case and movable between an on position and an off position. The appliance also includes a bistable actuator cooperating with the switch. The actuator is controlled by the sensing element, the control means and a camming surface of the base. Such an arrangement is expensive to fabricate when it is desired to control a switch by two sensing elements or a control element. 
     BRIEF SUMMARY OF THE INVENTION 
     It is an object of the present invention to simplify the structure and reduce the cost of manufacture of electric cooking appliances of the type described above. 
     The above and other objects are achieved by a safety and/or control device for an electric cooking appliance, the appliance having a case defining a cooking enclosure and means for heating the enclosure, the device comprising: 
     at least one switch arranged to close a circuit for supplying current to the heating means, this switch including a case and an actuating button, 
     at least one sensing element which is movable between a first position, called a “safe” position, corresponding to a predetermined configuration for placing the appliance into operation, and a second position, called an “unsafe” position, corresponding to another configuration in which the appliance should not be placed into operation, and 
     if desired, a control means accessible from outside the case and movable between an on position and an off position, 
     wherein the case of the switch is movably mounted in such a manner as to be capable of being displaced, by the control means while the control means move into the on position, or by the sensing element, from a non-active position of the case of the switch in which the switch is in an open or closed state and an active position of the case of the switch in which the switch is pivoted into another one of the closed and open states by the sensing element as the sensing element moves into its safe position, or as the control means moves into its on position, or in response to another detection element moving into its safe position. 
     These arrangements particularly permit the use of a device for detecting the presence of a bowl also as a main on-off switch of the appliance, or even to utilize a common switch for a device for detecting the presence of the bowl and a device for detecting the closing of a lid. 
     According to one embodiment, the case of the switch is mounted to be free to rotate about an axis, the sensing element in its safety position is arranged to act on the case, or the actuator button, of the switch, the control means in its on position or the other sensing element in its safety position are then capable of acting on the actuator button, or the case of the switch. 
     Advantageously, then, the case of the appliance is made of a plastic material and the axis of rotation is defined by molding a pivot shaft on that case. 
     Then, according to another feature of the invention, the control means are mounted to rotate and include a cam capable, in the on position of the control means to actuate the actuating button, or the case, of the switch, when the sensing element is in its safe position. 
     According to another embodiment, the case of the switch is mounted on the control means, or on one of the sensing elements, the actuating button of the switch is capable of being actuated by the sensing element, or the control means, or the other sensing element. 
     Objects according to the invention are further achieved by a safety and/or control device for an electric cooking appliance, the appliance having a case defining a cooling enclosure and means for heating the enclosure, the device comprising: 
     at least one switch arranged to close a circuit for supplying current to the heating means, this switch including a case and an actuating button, 
     at least one sensing element which is movable between a first position, called a “safe” position, corresponding to a predetermined configuration for placing the appliance into operation, and a second position, called an “unsafe” position, corresponding to another configuration in which the appliance should not be placed into operation, and 
     if desired, a control means accessible from outside the case and movable between an on position and an off position, 
     wherein a transmission element mounted on the sensing element, or on the control means, has a movable part including a control zone, displaceable by the control means or another sensing element, or the first-mentioned sensing element, and an actuation zone capable of cooperating with the switch when, on the one hand, the sensing element is in the safe position and, on the other hand, the control means is in the on position or when the other sensing element is in its safe position, the transmission element then occupying an active position in which the switch is in an open or closed state, the switch being in its other state when the first-mentioned sensing element is in the unsafe position, or when the control means is in the stop position, or when the other sensing element is in the unsafe position, the actuation zone then being capable of cooperating with the switch. 
     These arrangements also permit use of a device for detecting the presence of a bowl also as a main switch for turning the appliance on and off, or even utilizing a common switch for a device for detecting the presence of a bowl and a device for detecting the closing of a lid. 
     Advantageously, the actuation zone includes a cam surface extending transversely to the direction of displacement of the actuation zone between the position occupied by the actuation zone when, on the one hand, the sensing element is in the unsafe position and, on the other hand, the control means is in the stop position, or when the other sensing element is in the unsafe position, and the position occupied by the actuation zone when, on the one hand, the sensing element is in the safe position and, on the other hand, the control means are in the on position or the other sensing element is in the safe position. 
     This arrangement allows the actuation of the switch to be facilitated regardless of the order of actuation of the sensing element, or of the control means, or of the second sensing element. 
     According to one form of construction, the case of the switch is mounted in a fixed position in the case of the appliance and the actuation zone cooperates with the actuating button of the switch when the transmission element occupies the active position. 
     According to another form of construction, the case of the switch is mounted to be movable in the case of the appliance and the actuation zone cooperates with the case of the switch in order to push the actuating button of the switch against an abutment of the appliance case when the transmission element occupies its active position. Advantageously, in this form of construction, the case of the switch is mounted to be movable in rotation around an axis fixed to the case of the appliance. 
     Advantageously, the control means are capable of occupying several on positions. 
     The control means are advantageously formed by a control button, or dial, of a thermostat for setting a desired temperature. This construction eliminates the need to provide specialized control means for the on-off switch. 
     Preferred embodiments of the invention will be described below with reference to the drawings, it being understood that the scope of this invention is not limited by the specific illustrations provided. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is a perspective, exploded, detail view illustrating one embodiment of a device according to the invention. 
     FIG. 2 is a cross-sectional detail view illustrating the upper part of the device shown in FIG.  1 . 
     FIGS. 3,  4  and  5  are elevational detail views showing three operating positions of the device shown in FIGS. 1 and 2. 
     FIG. 6 is a simplified, pictorial, elevational view of a second embodiment of a device according to the invention. 
     FIG. 7 is a view similar to that of FIG. 6 showing a third embodiment of a device according to the invention. 
     FIGS. 8 a - 8   d  are simplified pictorial views of a fourth embodiment of a device according to the invention, shown in four different operating positions. 
     FIGS. 9 a - 9   b  are views similar to those of FIG. 8 showing a fifth embodiment of a device according to the invention in two different operating positions. 
     FIG. 10 a  is a simplified pictorial elevational view showing a sixth embodiment of a device according to the invention. 
     FIG. 10 b  is a simplified pictorial elevational detail view showing a part of a seventh embodiment of a device according to the invention which is a modification of the sixth embodiment. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a control and safety device according to the invention in an electric cooking appliance which has a case  1  that forms a housing provided to receive a removable bowl  2 , only a portion of case  1  and the upper edge of the lateral wall of bowl  2  being shown. 
     It would be understood that a complete bowl  2  will extend downwardly from the portion shown and will include a closed bottom. Case  1  is composed of an inner wall  10  delimiting the housing for receiving bowl  2 , and an outer wall  11 . Elements such as a thermostat or a thermal fuse will be installed in the space provided between walls  10  and  11 . 
     The control and safety device according to the invention includes a sensing element  4  which senses, or responds to, the presence of bowl  2  in a manner which will be described below. Sensing element  4  is disposed in case  1  between walls  10  and  11  and includes a shaft  12  slidably mounted in case  1 . Shaft  12  carries a lug  13  provided to cooperate with a folded-over a lip, or edge,  3  of the bowl  2  and a foot  9  provided to cooperate with a switch  6 . Lug  13  thus provides a zone for sensing the presence of bowl  2  and foot  9  provides a zone for actuating switch  6 . FIG. 2 shows sensing element  4  movably mounted against the restoring action of a restoring, or bias, means  5 , such as a spring. 
     When bowl  2  is present, and properly positioned, in the housing provided by case  1 , sensing element  4  is caused to descend into a first position in which switch  6  is able to close a circuit which supplies electric current to heating means  14  of the appliance. 
     If bowl  2  is not present or if it is not properly positioned in case  1 , sensing element  4  occupies a second, elevated, position corresponding to the position produced when means  5  alone acts on sensing element  4 . When sensing element  4  is in this second position, switch  6  will be in a position to open the circuit which supplies current to the heating means. 
     Switch  6  is associated with a control means  15  accessible from outside case  1 , control means  15  being positionable to occupy either an on position, in which switch  6  is able to be acted upon by the actuation zone of sensing element  4  when bowl  2  is properly seated in the housing in order to close the current supply circuit for the heating means, or an off position in which switch  6  opens the current supply circuit. 
     As shown in FIG. 1, control means  15  includes a wheel which carries a cam  16  mounted to be movable in rotation in case  1  about an axis defined by a shaft  14 . Shaft  14  carries, at one end, a button  7  which is rotatable by a user from the exterior of the appliance. Switch  6  is advantageously mounted to be rotatable about an axis defined by a shaft  8  which is fastened to, and extends from, wall  10 . Foot  9  is arranged to pivot switch  6  between first and second positions. Preferably, case  1  is made of a plastic material and shaft  8  is formed as an integral part of wall  10  when the latter is molded. 
     As better shown in FIGS. 3-5, switch  6  has a switch case  20  and an actuating button  17  arranged to cooperate with cam  16 . 
     According to one variation (not shown), actuating button  17  could cooperate with foot  9  of sensing element  4 , while case  20  of switch  6  then cooperates with cam  16 . According to another variation (not shown), control means  15  could be movable in translation and could control, for example, shaft  14  by the intermediary of a rack. 
     In the state shown in FIG. 3, sensing element  4  occupies its depressed position in that bowl  2  is properly installed in the housing defined by case  1 , and control means  15  occupies the off position. Case  20  of switch  6  comes to bear against foot  9  and actuating button  17  assumes a released position in which the circuit for supplying current to the heating means is open circuited. 
     In the condition shown in FIG. 4, sensing element  4  occupies the same position as in the state shown in FIG. 3, but control means  15  occupy the on position. Case  20  of switch  6  comes bear against foot  9  and actuating button  17  is pushed down by cam  16  to occupy a depressed position in which the current supply circuit is close circuited so as to supply heating current to the heating means. It will be noted that the raised surface portion of cam  16  has a substantial peripheral extent to permit control means  15  to have several on positions. This control means could, for example, be associated with a control button, or dial, for setting a thermostat to an adjustable temperature. 
     In the state shown in FIG. 5, sensing element  4  occupies the position in which bowl  2  is absent or is not properly positioned and control means  15  is in an on position. Case  20  of switch  6  comes to bear against a beveled edge  19  of foot  9  and actuating button  17  is in the released position in which the current supply circuit is open circuited. 
     The device shown in FIGS. 1-5 operates and is employed in the following manner. During displacement of control means  15  from the off position to an on position, cam  16  is in a position to tend to depress actuating button  17 . If bowl  2  is properly seated in the housing provided by case  1 , foot  9  pivots switch  6  toward cam  16  so that actuating button  17  is depressed and the circuit supplying electric current to the heating means is close circuited. 
     If bowl  2  is not present or is not properly positioned, bias means  5  push sensing element  4  upwardly into its second position. Switch then comes to bear on beveled edge  19  of foot  9 , so that cam  16  can no longer depress actuating button  17 . The current supply circuit for the heating means thus remains open circuited. 
     If bowl  2  is properly positioned in the housing provided by case  1 , sensing element  4  is depressed into its first position against the restoring force provided by bias means  5  and foot  9  pushes switch  6  against cam  16 . Actuating button  17  is then depressed and the current supply circuit is closed so that the appliance is placed into operation. 
     FIG. 6 shows an embodiment which includes a sensing element  4 ′ mounted for rotation about an axis defined by a shaft  18  extending from either wall  10  or  11  of case  1 . Sensing element  4 ′ is pivotable in opposition to a restoring force provided by a suitable bias means (not shown). A control means  15 ′ is movable in translation, in the direction indicated by the double headed arrow, between an on position and an off position, the latter position being shown in FIG. 6. A case  20 ′ of a switch  6 ′ is fixed to control means  15 ′. The current supply circuit for the heating means is close circuited when actuating button  17 ′ of switch  6 ′ is depressed and is open circuited when actuating button  17  is released. 
     The operation of the embodiment shown in FIG. 6 is comparable to that of the previously described embodiments. When bowl  2  is properly positioned in the housing defined by case  1  and the control means  15 ′ occupy an on position, which is to the left of the position shown in FIG. 6, bowl  2  pivots sensing element  4 ′ in a direction to depress actuating button  17  so that electric current is supplied to the heating means. If bowl  2  is not present or is not properly positioned, or if control means  15 ′ occupy the off position, actuating button  17 ′ will not contact sensing element  4 ′. Therefore, actuating button  17 ′ is released and electric current is not supplied to the heating means. 
     In the embodiment shown in FIG. 7, there is provided a detection element  4 ″ which is vertically movable against the restoring force of a bias spring (not shown) and control means  15 ′ are movable vertically between on and off positions. A case  20 ″ of a switch  6 ″ is fixed to sensing element  4 ″ and includes an actuating button  17 ″. In this embodiment, the circuit for supplying electric current to the heating means is closed when actuating button  17  is in its released position, as shown. The current supply circuit is open circuited when actuating button  17  is depressed. Control means  15 ″ are capable of occupying an off position in which actuating button  17 ″ contacts control means  15 ″ at or above the level of a line  22 , and is thus depressed. Control means  15 ″ can also be moved to an on position, which is the position illustrated in FIG.  7 . In this position, when bowl  2  is properly positioned in case  1 , actuating button  17  will contact control means  15 ″ at the level of line  21 . Therefore, actuating button  17 ″ will be released and electric current will be supplied to the heating means. When control means  15 ″ are in the on position and bowl  2  is absent from, or not properly positioned in, case  1 , sensing element  4 ″ and case  6 ″ will be displaced upwardly, so that actuating button  17 ″ will contact control means  15 ″ at, for example, the level of line  22 , and actuating button  17 ″ will therefore be depressed, opening the current supply circuit for the heating means. 
     The operation of a device according to the embodiment of FIG. 7 will be essentially the same as that for the preceding embodiments, from the point of view of the user. When bowl  2  is properly seated in case  1  and control means  15 ″ occupy the on position, actuating button  17 ″ is released and the heating means are supplied with electric current. If bowl  2  is not present or if control means  15 ″ occupy their off position, actuating button  17 ″ will be depressed by control means  15 ″ so that the heating means will not be supplied with electric current. 
     The embodiment shown in FIGS. 8 a  to  8   d  is associated with an appliance having a case  101  and a removable bowl  102 . A sensing element  104  is mounted to be movable in translation in case  101 . Sensing element  104  includes a shaft  112  mounted for sliding movement within case  101  against a return, or biasing, means  105 , such as a spring. Sensing element  104  is movable between a raised position, into which it is urged by return means  105 , which position is shown in FIGS. 8 a  and  8   c , and a lowered position which exists when bowl  102  is properly positioned in the case, the latter position being shown in FIGS. 8 b  and  8   d . When bowl  102  is properly positioned in case  101 , bowl  102  pushes sensing element  104  downwardly against the restoring action of return means  105 . The raised position of sensing element  104  corresponds to the unsafe position and the lowered position of sensing element  104  corresponds to the safe position. 
     Control means  115  are mounted in case  101  to be rotatable about an axis that is fixed to case  101  between an off position shown in FIGS. 8 a  and  8   b  and an on position, shown in FIGS. 8 c  and  8   d . Control means  115  include a disk having a circular peripheral portion  25  and a flat portion  26 . Control means  115  can occupy several on positions in addition to those shown in FIGS. 8 c  and  8   d . The periphery of the disk forming part of control means  115  is circular outside of flat portion  26 , and it is for this reason that the control means can have several on positions which can be associated, for example, with a control for the temperature setting of a thermostat. 
     The embodiment shown in FIGS. 8 a - 8   d  further includes a transmission element  31  connected to sensing element  104 . Transmission element  31  is formed by a piece having a certain degree of flexibility and having a part  32  that is fixed to shaft  112  and a part  33  which extends from shaft  112  and is movable laterally of the direction of movement of sensing element  104 . Movable part  33  includes a control zone  34  arranged to cooperate with the disk forming part of control means  115  and an actuating zone  35  arranged to cooperate with a switch  106  mounted in case  101 . 
     Switch  106  includes a switch case  120  fixed to case  101  and an actuating button  117  disposed to cooperate with actuating zone  35 . Actuating zone  35  has a camming surface  36  which extends in a direction transverse to the direction of displacement of actuating zone  35  between, on the one hand, the position occupied when sensing element is in the unsafe position and control means  115  are in the off position, represented in FIG. 8 a , and, on the other hand, the position occupied when sensing element  104  is in the safe position and control means  115  are in the on position, as shown in FIG. 8 d , in order to facilitate actuation of actuating button  117 . 
     The operation of this embodiment is the following. Sensing element  104  displaces transmission element  31  in a first direction which is substantially vertical and control means  115  displace transmission element  31  in a second direction which is substantially horizontal. 
     Transmission element  31  is in a raised position when detection element  104  is in a raised position, such as shown in FIGS. 8 a  and  8   c , and in a lowered position when sensing element is in a lowered position in the presence of bowl  102 , shown in FIGS. 8 b  and  8   d.    
     Transmission element  31  is in an undeformed condition when flat portion  26  engages control zone  34 , as shown in FIGS. 8 a  and  8   b , and in a horizontally deformed position when circular periphery  25  engages control zone  34 , as shown in FIGS. 8 c  and  8   d.    
     Transmission element  31  cooperates with actuating button  117  when sensing element  104  is in the safe position and control means  115  are in the on position, as shown in FIG. 8 d . Transmission element  31  is then in an active position. 
     Transmission element  31  does not depress actuating button  117  when detection element  104  is in its unsafe position or when control means  115  are in the off position, as shown in FIGS. 8 a  and  8   c.    
     The embodiment shown in FIGS. 9 a  and  9   b  differs from the embodiment of FIGS. 8 a - 8   d  in that the embodiment of FIGS. 9 a  and  9   b  includes a switch  106 ′ having a case  120 ′ which is mounted in case  101  to be pivotable about an axis defined by a pin  38  that is fixed to case  101 . Switch  106 ′ further includes an actuating button  117 ′ arranged to cooperate with an abutment  37  that is also fixed to case  101 . Actuating zone  35  of transmission element  31  is arranged to cooperate with case  120 ′ of switch  106 ′. 
     When transmission element  31  is in the active position, as shown in FIG. 9 b , actuating zone  35  pushes case  120 ′ downwardly to push actuating button  117 ′ against abutment  37  in order to depress actuating button  117 . When transmission element  131  is not in the active position, as shown in FIG. 9 a , actuating zone  35  no longer presses on case  120 ′ and case  120 ′ can pivot, under the action of the restoring force of a spring associated with actuating button  117 ′, so that actuating button  117 ′ is no longer depressed and assumes its extended, or released, position. 
     Actuating zone  35  includes a camming surface  36  which extends transverse to the direction of displacement of actuating zone  35  between, on the one hand, the position occupied when sensing element  104  is in the unsafe position and control means  115  are in the off position, shown in FIG. 9 a , and, on the other hand, the position occupied when sensing element  104  is in the safe position and control means  115  are in the on position, as shown in FIG. 9 b , in a manner to facilitate pivoting of case  120 ′ around the axis of pin  38  in order to cause actuating button  117 ′ to interact with, and be depressed by, abutment  37 . 
     Numerous improvements can be provided to the devices disclosed herein without departing from the framework of the invention. 
     The control means and the sensing element can be movable between two positions with a movement different from a rotational movement or a translational movement. 
     According to other embodiments of the invention, the control means can be replaced by a second sensing element. Two such embodiments are shown in FIGS. 10 a  and  10   b.    
     FIG. 10 a  shows one such embodiment which includes a sensing element  204  that responds to the presence of a bowl  202  in the housing formed by case  201 . When bowl  202  is properly positioned in the housing, sensing element  204  is displaced downwardly against the restoring force produced by a restoring means  205 . A second sensing element  204 ′, which is mounted for movement in the same manner element  204 , is disposed to be displaced downwardly, against the restoring force produced by a restoring means  205 ′, in response to or closing of a lid  241  of the appliance. Lid  241  carries a finger  240  which is positioned to engage sensing element  204 ′ in order to move element  204 ′ downwardly when lid  241  is moved to its closed position. 
     A switch  206  has a case  220  which is fixed to case  201  of the appliance. Switch  206  further has an actuating button  217  which faces upwardly and is normally in a released, or raised, position. 
     A bar-shaped actuating member  242  extends between sensing elements  204  and  204 ′. Actuating member  242  has two opposed ends, each of which is pivotally connected to a respective one of sensing elements  204  and  204 ′. 
     If either sensing element  204  or  204 ′ is in its raised position, which is the position shown for element  204 ′, actuating member  242  can not engage button  217 . Only if both sensing elements  204  and  204 ′ are in their depressed position will actuating member  242  bear against actuating button at  217  in order to move that button to its depressed position. When button  217  is moved to its depressed position, switch  206  acts to close the circuits for supplying current to the heating means of the appliance. 
     For FIG. 10 a  further shows, for the sake of completeness, a seal  250  that will engage the upper edge of bowl  202  when lid  241  is in its closed position. 
     FIG. 10 b  shows a variation which is identical to the embodiment of FIG. 10 a , except for the following differences. In the embodiment of FIG. 10 b , case  220  of switch  206  is fixed to actuating member  242 , actuating button  217  is directed downwardly, and case  201  is provided with a part  201  ′ having a surface against which actuating button  217  will come to bear, and which will move button  217  to its depressed position, only when both sensing elements  204  and  204 ′ are in their respective depressed positions. In the case of each of the embodiments of FIGS. 10 a  and  10   b , actuating button  217  of switch  206  will not be moved to its depressed position if bowl  202  is not correctly positioned in the housing defined by case  201 , or if lid  241  is not in its closed position. 
     This application relates to subject matter disclosed in French Application number 99 02260, filed on Feb. 19, 1999, the disclosure of which is incorporated herein by reference. 
     While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention. 
     The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.