EP2469551B1

EP2469551B1 - Cooking appliance having pop-out type control knob assembly

Info

Publication number: EP2469551B1
Application number: EP11194038.3A
Authority: EP
Inventors: Metin Erbay; Gurkan Gundogdu; Emrah Torun; Ramazan Uygun
Original assignee: BSH Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2010-12-22
Filing date: 2011-12-16
Publication date: 2019-02-20
Anticipated expiration: 2031-12-16
Also published as: TR201010712A1; EP2469551A3; EP2469551A2

Description

Field of the Invention

The present invention relates to a cooking appliance comprising at least one pop-out control knob assembly, and particularly relates to a gas cooking appliance having at least one push-push pop-out type knob assembly permitting two-step operation of a gas valve mechanism of the cooking appliance.

Background of the Invention

Pop-out knobs, operated by way of activation and deactivation steps are well known with their unique structure that enables an operation mode when extended, and provides hidden view with passive mode when retracted. Said extension and retraction of the knob is conducted by way of a simple finger tip depression applied onto the external flat surface of the knob. These classical assemblies find application areas in wide variety of household appliances and electronic devices. However, the control knobs of this type, in extended position, are generally not suitable for operation of the conventional gas valves of the cooking appliances. This is because, due to the safety regulations, a control knob needs to be operated by way of sequential bidirectional movement, namely; pushing in a first direction perpendicular to the knob in order to start up the flame, and then rotating said knob axially in order to adjust the gas flow rate through burners.
The classical pop-out knobs, as disclosed for instance in DE-19801300-A1 , comprise a spring inbetween a knob housing and a heart shaped guiding body having corresponding channels thereon, wherein a guiding element may move along said channels for selectively locking the knob assembly in a certain position. This position ensures the knob assembly to stay in the retracted position against the spring forces. This effect is achieved by snagging of a guiding element in a detent of the heart shaped guiding body. However, this configuration provides one step locking, namely only for keeping the knob retracted in passive mode. Those skilled in the art will appreciate that the arrangement as alluded above is not suitable for use in the gas cooking appliances which require an additional locking step for starting up the flame.
To solve this problem, a control knob assembly for a cooking appliance comprising a number of guiding bodies each having two opposite detents in order to ensure two-step locking is provided in the U.S. Patent No. 5,384,442 . According to this arrangement, the guiding elements (i.e. guide followers) are releasibly secured in two opposite notches (detents) contained in the tracks enabling two-step operation of the gas valve. Moreover, the assembly as disclosed comprises plurality of tracks (e.g. four tracks around the periphery of the cylindrical track body; see col. 4 - lines 13-16) to provide robust knob engagement. The arrangement further needs bosses and serrated edges (see col. 5 - lines 9-12) for prohibiting disengagement of guide followers from the detents.
In the patent application numbered CA 2 112 761 A1 , a control knob assembly includes a control knob and a track body disposed in the control knob. A cam arm mounted at one end thereof to the control knob contains on the other end a cam follower which rides in a track disposed within a top surface of the track body. The control knob is slidable over the track body, and is alternatively locatable in extended and retracted positions. When the control knob is located in a retracted position, the cam follower is releasably secured in a notch contained in the track. A pushbutton stop located in the control knob is springloaded to move to a radially extended position when the control knob is extended, thereby aligning the pushbutton stop with an extended portion of the track body, permitting actuation by the user of a two-step gas valve by sequentially depressing and rotating the control knob.
In the patent application numbered EP 0 173 820 A1 , a retractable rotary-knob unit for adjusting the switching or control devices disposed behind a switch panel in domestic appliances such as cookers, washing machines or the like, which comprises a rotary knob , a compression spring acting in the axial direction on the rotary knob, a sleeve-like sliding member formed on the rotary knob, a guide sleeve fitted into the sliding member and having a central socket insert, and a closed channel proved at one wall side of the guide sleeve and having a detent position for a sliding pin, characterised by the following features : the sliding pin is part of a movably mounted separate holder, the holder is provided with a pivot pin, the pivot pin is guided for pivoting in a bearing provided in the rotary knob, associated with the top of the holder is a spring element which is supported against the inner wall of the sliding member and holds the sliding pin in engagement with the channel, the spring element is coupled to the pivot pin of the holder.
The quality of the engagement of the control knob assembly as elaborated above still needs to be improved while eliminating exhaustive amount of details tailored for better engagement.
It is therefore an objective of the present invention to provide a cooking appliance having a control knob assembly which eliminates the need for exhaustive list of details (e.g. plurality of tracks, bosses, serrated edges etc.). A further object of the present invention is to provide a gas cooking appliance comprising a specially designed frontal notch having a purposive protrusion that eliminates unintentional disengagement of a guiding element by way of a perpendicular obstruction during rotation of the knob assembly. These and other objects that may be apparent to those skilled in the art after reviewing the following description are achieved through a cooking appliance as disclosed in claim 1.

Summary of the Invention

A cooking appliance comprising at least one gas valve and a pop-out type control knob assembly coupled to said gas valve is disclosed. The knob assembly as referred in the present invention comprises a guiding body residing in a knob, a guiding element adapted to travel on a surface of said guiding body, and a spring (not shown) located in between the guiding body and the knob. Said guiding body comprises a number of track grooves forming a loop for travel of the guiding element, and a central ridge having at least two notches located oppositely to each other. In further aspects of the invention the control knob assembly is adapted to stay in a first locking position by retraction of the knob and engagement of the guiding element into a backward notch, and to stay in a second locking position by extension of the knob and engagement of the guiding element into a frontal notch.
Therefore, by way of the two-step locking, the pop-out control knob is suitable for operation of the cooking appliances having conventional gas valves. The frontal notch of the ridge advantageously comprises a recession adapted to engage with the guiding element, and further comprises a protrusion bordering side of which is protruding preferably parallel to the longitudinal axis of the guiding body. The groove having said protrusion on one side includes, at its other side, at least one confronting point opposite to the frontal notch. One of the missions of said confronting point is preventing unintentional evasion of the guiding element through the previous recession. There is the predetermined distance of y inbetween the end point of protrusion of the invention and projection of the confronting point to the perpendicular lateral axis of the control knob assembly. This special arrangement of the notch preferably provides a perpendicular detention when the guiding element abuts to the end point of the bordering side of said protrusion. Therefore, a solution for one of the objectives of the invention is attained by prevention of the unintentional disengagement of the guiding element by the control knob assembly as identified above.
The cooking appliance of the present invention involves a passive mode when the pop-out type control knob is not used, and an activation mode when said knob is operated. The guiding element is permitted to engage into the rear notch so that the entire knob is kept in retracted position in passive mode. On the other hand, in the activation mode, the guiding element is freed from the rear notch and and forced through the first recession under spring forces so that the knob may moves outside of the cooking appliance, and thereafter said guiding element which is moved through the control knob assembly track grooves into the first recession is enforced for abutting to the second recession at the utmost opened position outside front panel of the appliance. For ensuring that the guiding element may move from the second recession through the frontal notch in a position where radial rotation of the knob is not hindered in operation, a continuous pushing in the horizontal axis is applied onto the knob and said guiding element is permitted to engage with the frontal notch such that it may be shifted to activate the gas valve during start up of the flame.
After providing the flame, the knob in utmost extended position is pushed so that it may return to a mode where flame is interrupted but gas flow is active, and the guiding element is allowed to lean against a third recession under spring forces after hitting the confronting point opposite to the frontal notch of the guiding body. Allowing the gas flow in the position of this recession is ensured by way of pushing the knob again and allowing the guiding element to move through the second track groove into a fourth recession, and subsequently, in the utmost retracted position through rearward side of the front panel, the guiding element is enabled to engage into the rear notch by way of spring forces after removing depression on the knob to provide the retracted position.

Brief Description of the Drawings

The attached drawings are solely given for illustrating an embodiment of the invention, wherein;

Figure 1 shows a planar view of a knob assembly according the present invention.
Figure 2a and 2b are frontal and backward perspective views of the knob assembly according to the present invention.
Figure 3 is a partly exploded view of the knob assembly according to the present invention wherein the knob, inner housing and guiding body of the assembly are shown separately.
Figures 4 is a planar view a guiding body according to an embodiment of the present invention.
Figure 5a and 5b show different perspective views of the guiding body according to Figure 4.
Figure 6 is a planar view a guiding body according to another embodiment of the present invention.
Figure 7a and 7b show different perspective views of the guiding body according to Figure 6.

Detailed Description of the Invention

The present invention provides a cooking appliance (not shown) having one or plurality of pop-out type knob assemblies dedicated to solve the aforementioned problems of the prior art. The general structure of the knob assembly (1) in accordance with the present invention is represented in Figures 1, 2a, 2b and 3.
With reference to these figures, there is provided a knob assembly (1) comprising a knob (10), an inner body (20) and a guiding body (30) which are sequentially nested in each other. The knob (10), which is preferably of cylindrical nature, comprises a backward flush surface (11) upon which the users may readily apply a perpendicular thrust in order to activate and deactivate the entire knob assembly (1). The knob assembly of the invention is designed to be activated by the first push of the user and then starting up the flame with a second push, and further to be deactivated with a third push of the user. During this loop, the knob carries out two locking steps at locking positions of deactivation (retraction) and gas start up. With the term "deactivation" it is to be construed that the knob (10) is kept in retracted position such that it is projection from the front panel of the appliance (not shown) is reduced.
The knob (10) as referred above preferably comprises a number of longitudinal grooves (12) along which the corresponding projections (25) of the inner body (20) slidably engage such that said inner body (20) is fixed inside said knob (10). In this preferred form, said projections (25) may be formed on a ring shaped ratchet (21) attached to said inner body (20). The inner body (20) as shown in detail with Figure 3 comprises a central opening (22) having longitudinal channels (23) adapted to receive corresponding projections (44) of the guiding body (30). The assembly (1) of the invention further comprises a guiding element (24), preferably in the form of a pin, adapted to move through the corresponding track grooves on the guiding body (30).
The guiding body (30) as referred supra comprises an opening (31) so as to receive corresponding shaft of a gas valve (not shown) assembled to the cooking appliance. In a preferred embodiment of the present invention, the upper surface of said guiding body (30) comprises a number of track grooves (32, 33) forming a loop, and a central ridge (41) having two notches (37, 42) located oppositely to each other. Referring now to Figures 5a and 7a, the backward notch (42) located in the furthest end of the ridge (41) is adapted to provide a first locking position, and when guiding element (24) resides in this notch (42), entire knob (10) is kept in the retracted position (passive mode). When the user wants the knob (10) to be extended (activated) outside the front panel of the cooking appliance, he/she may simply push the depressible surface (11) of the knob (10) so that the guiding element (24) would be freed from the notch (42) and move through the first recess (43) and first track groove (32) until abutting to the second recess (34) with the help of the spring forces. Thereby, a first move for "activation" of the knob assembly (1) becomes completed. The guiding element (24) continues to remain in said recess (34) until the user makes another push through the knob (10).
Following activation of the control knob (10) by way of the above manner, it becomes ready for controlling the gas valve associated thereto. For this purpose, a second notch (37) is provided in the front end of the ridge (41) so that, when the user applies a thrust for a second time, the guiding element (24) may move from the recent recess (34) through the second notch (37). This frontal notch (37) of the ridge (41) advantageously comprises a recess for engaging with the guiding element (24), and also a protrusion (38) one side of which is preferably protruding parallel to the longitudinal axis of the guiding body (30). Said protrusion (38) provides hindrance when the guiding element (24) abuts to its bordering side. In different embodiments of the invention, said protrusion may have the angles intercepting the longitudinal axis of the guiding body with various angles for hindering unintentional movement of the guiding element (24).
The protrusion (38) is preferably provided at a frontal end of the track groove (32, 33) on the guiding body (30), whereas there exists a confronting point (391) opposite to the frontal notch (37) at the other side of the groove (32, 33) for preventing said guiding element (24) unintentionally to retreat to the previous recession (34). On the other hand, there is provided a distance (a) having a predetermined length between the end point (381) of the protrusion (38) and perpendicular projection of the confronting point (391) to the lateral axis (y_k) of the control knob assembly. Said distance is, at maximum, equal to the width of the groove (32, 33) in lateral axis (y_k), and preferably is less than width of the groove (32, 33) at lateral axis (y_k). This special arrangement of the said notch (37) preferably provides a perpendicular detention when guiding element (24) leans against the end point (381) of the protrusion (38). Thus, unintentional detachment of the guiding element (24) is prevented by way of the control knob assembly (1) as defined above.
As the user continues to apply the thrust on the knob (10), the guiding element (24) is snagged in the notch (37) causing the guiding body (30) to be pushed along the longitudinal horizontal axis (x_h) which enables activation of the gas valve in starting up the flame. In this position, the knob (10) may also be moved in the radial direction in order to adjust the gas flame as very well known in gas cooking appliances.
This step, however, involves various problems especially when bidirectional movement is simultaneously applied on the knob assembly (1). As explained in the background art the guiding body (30) is subject to a rotation force which may render the guiding element (24) freed from said notch (37).
Therefore, it is one of the objects of the present invention to improve this notch (37) and adapting it for prevention of unintentional disengagement of the guiding element (24). This objective is achieved through providing one edge of the frontal notch (37) with a protrusion (38) parallel to the longitudinal axis (x_h) such that, when guiding element (24) abuts to the bordering side of the protrusion (38), said bordering side responses with a perpendicular force against the guiding element (24), thereby its unintentional disengagement is prevented. The notch (37) may further comprise an inclination part (35) opposite to said protrusion (38) in order to facilitate sliding of the guiding element (24) through the notch (37).
In accordance with a preferred embodiment of the present invention, the frontal notch (37) designed to prevent unintentional disengagement of the guiding element (24) is configured with an angled "U" shaped recess wherein one bordering side of the recess is formed by said protrusion (38) as shown in Figures 6, 7a and 7b.
In another preferred embodiment of the invention, said notch (37) is configured with an angled "V" shaped recess wherein one bordering side of the recess merges with the perpendicular protrusion (38) as shown in Figures 4, 5a and 5b.
After carrying out the second locking step as disclosed above and activating the gas flame in the cooking appliance the guiding element (24) moves to a third recess (39) with effect of the spring forces until the user decides to deactivate the gas valve and applies a further push to retract the knob assembly (1) into the original position (passive mode). For this purpose, the guiding body (30) comprises a second track groove (33) by way of which the guiding element (24) moves through a fourth recess (40). Then the user may leave the knob (10) permitting the guiding element (24) to sit on the backward notch (42), thereby return to its first locking position (retraction).
Said backward notch (42) may be of a classical parabolic nature widely applied in the technical field of the invention. Although not essential for the present invention, its shape may be optimized depending on the shape and position of the details (e.g. ridge, track grooves, recesses etc.) of the guiding body (30).
The frontal notch (37) which constitutes essence of the present invention may have a shape other than the angled "U" and "V" recesses such as a semi-circular or semi-parabolic recession as long as the protrusion (38) is arranged in parallel to the longitudinal axis (x_h) and perpendicularly confronted with the guiding element (24) so that unintentional disengagement of said guiding element (24) may completely be eliminated.
Besides these benefits, it is immediately clear from the above description that, with the strong engagement of guiding element (24) and frontal notch (37), most of the additional components of the conventional knob assemblies, such as plurality of tracks, bosses and serrated edges for strengthening the overall structure are substantially eliminated. Further aspects and advantages of the present invention shall be apparent for those skilled in the art with the above explanations and appended drawings.

Claims

A cooking appliance comprising at least one gas valve and a pop-out type control knob assembly (1) coupled to said gas valve, said knob assembly (1) comprising a guiding body (30) residing in a knob (10), a guiding element (24) adapted to travel on a surface of said guiding body (30), and a spring located in between the guiding body (30) and the knob (10); said guiding body (30) comprising a number of track grooves (32, 33) forming a loop for travel of the guiding element (24), and a central ridge (41) having at least two notches (37, 42) located oppositely to each other; the control knob assembly (1) being adapted to stay in a first locking position by retraction of the knob (10) and engagement of the guiding element (24) into a backward notch (42), and to stay in a second locking position by extension of the knob (10) and engagement of the guiding element (24) into a frontal notch (37),
characterized in that;
said frontal notch (37) comprises a recession adapted to engage with the guiding element (24), and further comprises a protrusion (38) that is adapted to detent the guiding element (24) and wherein said protrusion (38) protrudes parallel to a longitudinal axis (x_h) of the guiding body (30) for applying a perpendicular detention when said guiding element (24) abuts to the bordering side of said protrusion (38).
A cooking appliance according to claim 1, wherein the knob assembly (1) comprises at least one confronting point (391) between a second recess (34), which is located at the other side of the groove (32, 33) having the protrusion (38) on one side, and third recess (39) opposite to said point (391).
A cooking appliance according to claim 1, wherein the knob assembly (1) comprises an intermediary distance (a) having a predetermined length inbetween the end point (381) of said protrusion (38) and perpendicular projection of the confronting point (391) to the lateral axis of the knob (10).
A cooking appliance according to claim 1, wherein the knob assembly (1) further comprises an inner body (20) having an opening (22) for receiving and nesting the guiding body (30).
A cooking appliance according to claim 1, wherein the guiding element (24) is configured as a pin.
A cooking appliance according to claims claim 1, wherein the knob (10) is configured with a cylindrical body having a depressible surface (11).
A cooking appliance according to claim 1, wherein the recession of the frontal notch (37) is formed in an angled "U" shape.
A cooking appliance according to claims claim 1, wherein the recession of the frontal notch (37) is formed in an angled "V" shape.
A method for operating a pop-out type control knob assembly (1) involving a passive mode when a gas cooking appliance is not operated, and an activation mode when said appliance is operated, the method comprising the steps of;
- enabling a guiding element (24) to attach to a backward notch (42) for keeping an entire knob in retracted position in passive mode,

- releaving said guiding element (24) from the backward notch (42) and moving the same into a first recession (43) under spring forces for moving the knob (10) outside of the front panel of cooking appliance in activation mode,

- bringing the guiding element (24), which is permitted to get into a groove (32) of the control knob assembly (1) by enforcing it into the first recession (43), into a second recession (34), thereby bringing the same into an utmost extended position,

- continuing to push onto the knob (10) along a longitudinal axis (x_h) so that the guiding element (24) may move from the second recession (34) through the frontal notch (37) at a position where radial rotation of the knob is not hindered,

- bringing the guiding element (24) for engagement with the frontal notch (37) by moving and activating gas valve during start up of flame,

- bringing the guiding element (24) again at the utmost extended position outward of front panel allowing the gas flow by way of hitting it to the confronting point (391) opposite to the frontal notch (37) of the guiding body (30) under influence of the spring and permitting it to lean against a third recession (39) by applying push on the knob (10) for interrupting the flame after the course of flaming,

- bringing the guiding element (24) into a fourth recession (43) through movement in the second groove (33) by pushing the knob (10) for returning the passive mode,

- removing the depression on the knob and engaging the guiding element (24) to the backward notch (42) for providing retracted position towards back side of front panel in utmost retracted form.