GB2186346A

GB2186346A - Rotary switch assembly for gas flow control in a gas-burning appliance

Info

Publication number: GB2186346A
Application number: GB08629671A
Authority: GB
Inventors: Franz A Herrmann
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-12-17
Filing date: 1986-12-11
Publication date: 1987-08-12
Also published as: IT1199752B; FR2591720A1; FR2591720B1; DE3544583C2; IT8624014V0; DE3544583A1; IT8622663A0; GB8629671D0; GB2186346B

Abstract

A rotary switch assembly for the control of gas flow to a burner in a gas cooker comprises a rotary knob (2) which is axially displaceable between an operative position in which it protrudes from a housing (12) of the assembly and a rest setting in which it is retracted into the housing. The knob is arranged to be axially displaceable on an axle member (6). Detent elements (10, 11, 14, 15), extending in the direction of axial displacement, are arranged on the knob (2), the axle member (6) and the housing (12), in a zero angular setting of the knob (2) and outside the operative position of the knob (2) interengage to secure the knob against rotation. The detent elements permit axial displacement of the knob relative to the axle member when the knob is in its zero setting, but in any other rotational setting of the knob the detent elements cause the axle member to be entrained by and displaced with the knob in order to open a gas flow control valve which is further controlled by a thermo-electric ignition protection at the burner. <IMAGE>

Description

SPECIFICATION Rotary Switch Assembly for Gas Flow Control in a Gas-burning Appliance The present invention relates to a rotary switch for gas flow control in a gas-burning appliance, especially for the control of gas flow to a burner of a gas cooker or gas hob.

Rotary switches with rotary knobs axially retractible into an appliance front are known in the context of electrical power control in electric cookers (DE-OS 33 45 312, DE-OS 27 01 017). A rotary switch of that kind can, for example, be constructed in such a way that the rotary knob is associated with a scale ring carrying marking symbols. In the operative position, the rotary knob together with this scale projects out of the appliance front side and can be turned by hand into the appropriate settings for heating power steps. For retraction into a rest setting, the knob is axially pushable into the appliance front until the end face of the knob is flush with the appliance front.

Through axial pressure on the end face of the knob, an appropriately functioning detent mechanism is released and the knob together with the scale ring is pushed through spring effect out of the front of the appliance and back into the operative, i.e. rotary actuation, setting. To enhance the visibility of the marking symbols on the scale ring, the ring can consist of transparent or translucent material and illuminating equipment can be arranged in the interior of the appliance housing to brighten the ring.

It would be desirable to structure rotary switches of this kind so that they can be employed for the use in gas cookers or hobs, i.e. for the control of gas flow to gas burners. I n the case of both rotary electrical switches and rotary gas switches (valves) for heating power control, the switches are movable into different rotational settings associated with respectively different heating powers. Gas controls, however, additionally require a setting criterion for influencing thermo-electric ignition protection. This ignition protection is usually actuated by way of the rotary switch, namely through a short-stroke axial inward movement of the knob by hand against a spring force. If the flame burns in the region of a thermal element, then the gas feed channel opened by this inward movement continues to be held in this open setting.Otherwise, the gas feed to the burner is interrupted on release of the rotary knob.

According to the present invention there is provided a rotary switch assembly for gas flow control in a gas-burning appliance, the assembly comprising a housing, a rotary knob which is mounted in the housing to be axially displaceable relative thereto from an operative position in which it protrudes from the housing to a rest position in which it is at least partially retracted into the housing and which in the operative position is rotatable relative to the housing for a first control function, means selectably actuable by said axial displacement of the knob for a second control function, and detent elements so interengageable in the direction of said axial displacement that the knob is secured against rotation relative to the housing in any axial position other than the operative position, that in a predetermined rotational setting of the knob relative to the housing the knob is axially displaceable from the operative to the rest position without actuation of said means and that in any other such rotational setting the knob is axially displaceable from the operative to the rest position with actuation of said means.

In a preferred embodiment, the knob in the rest setting is retracted into the front of an appliance and is arranged to be axially displaceable, but rotationally secure on an axle member. Detect gates, which are aligned axially, are arranged at the knob and in the housing and stand opposite each other at a gap in that setting of the knob which is associated with the zero setting. Outside the operative position of the knob the detent gates interengage as rotational securing for the knob, and a gate, the actuating range of which stands opposite switch means for a thermo-electric ignition protection, which outside the zero setting of the knob in axial direction are actuable in this direction, is arranged at the knob. A rotary switch equipped with these features can be retracted into the appliance front when it is in its zero setting, i.e.

when the burner is not alight, and can also be employed as an actuating device for a thermo electric ignition protection, wherein outside the zero setting, a stop/passage valve for the gas flow to the burner is opened through axial pressure on the knob against spring force until this setting is held through this valve by way of the thermo-electric ignition protection through the heat flame in the region of the gas burner.

Preferably, the knob is rotatably and axially slidably mounted on an axle member and the detent elements comprise first and second elements provided in a ring which is rotatably mounted on the knob to be secure against axial displacement relative thereto, a third element arranged on the housing to be in sliding engagement with the first element in any axial position of the knob and a fourth element arranged on the axle member to be in relative sliding engagement with the second element when the knob is in the predetermined rotational setting and in any axial position other than the operative position and to be so engaged by the ring when the knob is in any other rotational setting and is displaced from the operative to the rest setting as to cause the axle member to move with the knob for actuation of said means. Thus, the ring can have guide gates aligned to be extending axially and be secured against axial displacement on the knob and a gate piece, which extends axially over the adjustment range of the ring, can be fixedly arranged in the housing. A gate counterpiece, which extends axially aligned over the displacement range of the ring outside that region of the gate ring which is associated with the operative position of the knob, can be arranged on the axle member. Consequently, outside that setting of the knob which is associated with the zero setting the mutually displaced gate parts transmit an axial movement exerted on the rotary knob to switch means, for the thermo-electric

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

SPECIFICATION Rotary Switch Assembly for Gas Flow Control in a Gas-burning Appliance The present invention relates to a rotary switch for gas flow control in a gas-burning appliance, especially for the control of gas flow to a burner of a gas cooker or gas hob.

Rotary switches with rotary knobs axially retractible into an appliance front are known in the context of electrical power control in electric cookers (DE-OS 33 45 312, DE-OS 27 01 017). A rotary switch of that kind can, for example, be constructed in such a way that the rotary knob is associated with a scale ring carrying marking symbols. In the operative position, the rotary knob together with this scale projects out of the appliance front side and can be turned by hand into the appropriate settings for heating power steps. For retraction into a rest setting, the knob is axially pushable into the appliance front until the end face of the knob is flush with the appliance front.

Through axial pressure on the end face of the knob, an appropriately functioning detent mechanism is released and the knob together with the scale ring is pushed through spring effect out of the front of the appliance and back into the operative, i.e. rotary actuation, setting. To enhance the visibility of the marking symbols on the scale ring, the ring can consist of transparent or translucent material and illuminating equipment can be arranged in the interior of the appliance housing to brighten the ring.

It would be desirable to structure rotary switches of this kind so that they can be employed for the use in gas cookers or hobs, i.e. for the control of gas flow to gas burners. I n the case of both rotary electrical switches and rotary gas switches (valves) for heating power control, the switches are movable into different rotational settings associated with respectively different heating powers. Gas controls, however, additionally require a setting criterion for influencing thermo-electric ignition protection. This ignition protection is usually actuated by way of the rotary switch, namely through a short-stroke axial inward movement of the knob by hand against a spring force. If the flame burns in the region of a thermal element, then the gas feed channel opened by this inward movement continues to be held in this open setting.Otherwise, the gas feed to the burner is interrupted on release of the rotary knob.

According to the present invention there is provided a rotary switch assembly for gas flow control in a gas-burning appliance, the assembly comprising a housing, a rotary knob which is mounted in the housing to be axially displaceable relative thereto from an operative position in which it protrudes from the housing to a rest position in which it is at least partially retracted into the housing and which in the operative position is rotatable relative to the housing for a first control function, means selectably actuable by said axial displacement of the knob for a second control function, and detent elements so interengageable in the direction of said axial displacement that the knob is secured against rotation relative to the housing in any axial position other than the operative position, that in a predetermined rotational setting of the knob relative to the housing the knob is axially displaceable from the operative to the rest position without actuation of said means and that in any other such rotational setting the knob is axially displaceable from the operative to the rest position with actuation of said means.

In a preferred embodiment, the knob in the rest setting is retracted into the front of an appliance and is arranged to be axially displaceable, but rotationally secure on an axle member. Detect gates, which are aligned axially, are arranged at the knob and in the housing and stand opposite each other at a gap in that setting of the knob which is associated with the zero setting. Outside the operative position of the knob the detent gates interengage as rotational securing for the knob, and a gate, the actuating range of which stands opposite switch means for a thermo-electric ignition protection, which outside the zero setting of the knob in axial direction are actuable in this direction, is arranged at the knob. A rotary switch equipped with these features can be retracted into the appliance front when it is in its zero setting, i.e.

when the burner is not alight, and can also be employed as an actuating device for a thermo electric ignition protection, wherein outside the zero setting, a stop/passage valve for the gas flow to the burner is opened through axial pressure on the knob against spring force until this setting is held through this valve by way of the thermo-electric ignition protection through the heat flame in the region of the gas burner.

Preferably, the knob is rotatably and axially slidably mounted on an axle member and the detent elements comprise first and second elements provided in a ring which is rotatably mounted on the knob to be secure against axial displacement relative thereto, a third element arranged on the housing to be in sliding engagement with the first element in any axial position of the knob and a fourth element arranged on the axle member to be in relative sliding engagement with the second element when the knob is in the predetermined rotational setting and in any axial position other than the operative position and to be so engaged by the ring when the knob is in any other rotational setting and is displaced from the operative to the rest setting as to cause the axle member to move with the knob for actuation of said means.Thus, the ring can have guide gates aligned to be extending axially and be secured against axial displacement on the knob and a gate piece, which extends axially over the adjustment range of the ring, can be fixedly arranged in the housing. A gate counterpiece, which extends axially aligned over the displacement range of the ring outside that region of the gate ring which is associated with the operative position of the knob, can be arranged on the axle member. Consequently, outside that setting of the knob which is associated with the zero setting the mutually displaced gate parts transmit an axial movement exerted on the rotary knob to switch means, for the thermo-electric ignition protection, by way of the axle member.

Alternatively, the detent elements comprise a first element fixedly arranged on the knob and a second element movably arranged at the housing to be in relative sliding engagement with the first element when the knob is in the predetermined rotational setting and in any axial position other than the operative position and to be so engaged bythefirst element when the knob is in any other rotational setting and is displaced from the operative to the rest setting as to move with the knob for actuation of said means. Thus, a guide gate, which extends axially aligned, can be arranged locally fixed on the knob and a countergate, which in that setting of the rotary knob, which is associated with the zero setting, is in alignment at a gap with the knob, can be mounted in the housing to be longitudinally displaceable over the adjustment range of the guide gate of the knob outside the region, associated with the operative position, of the guide gate which transmits a press-in movement exerted axially on the knob, outside its setting associated with the zero setting, onto switching means of the thermo-electric ignition protection.