GB2109535A

GB2109535A - A control knob

Info

Publication number: GB2109535A
Application number: GB08133494A
Authority: GB
Inventors: Dennis James Chambers
Original assignee: THORN GAS APPLIANCES Ltd
Current assignee: THORN GAS APPLIANCES Ltd
Priority date: 1981-11-06
Filing date: 1981-11-06
Publication date: 1983-06-02
Also published as: DE8229358U1; FR2516277B3; FR2516277A3; GB2109535B

Abstract

A control knob 3 is provided on a gas fire or other appliance having an external wall 2. The knob 3 has a finger grip portion 7 affixed to a control spindle 5 which regulates the amount of gas fed to a gas burner of the fire. A cover portion 6 is spring mounted on finger grip portion 7 by a spring 8 and can be depressed exposing end 7b of grip portion 7. Portion 6 has to be depressed so that end 7b can be gripped and turned to rotate spindle 5. <IMAGE>

Description

SPECIFICATION A control knob and an appliance including such a control knob This invention relates to a control knob and more particularly but not exclusively to a control knob for a gas-fired appliance, for example a gas fire or gas cooker.

In gas fires control knobs are usually located on and project outwardly from an external wall. Such knobs tend to be easy to grip and turn to actuate control means in the form of a gas supply regulator to the burner of the gas fire. Such knobs tend to be relatively easy for children to operate and also there is a possibility that such knobs may be turned on inadvertently. In particular once the fire is turned on such knobs tend to be all too readily accessible to either increase or decrease the gas supply to the burner. Many projecting knobs look unsightly and are located so that they may be dangerous since a person who happens to inadvertently knock the knob may sustain damage.

Additionally, such knobs may be hazardous if it is possible for a child to turn the knob on without the burner lighting, thus allowing gas to escape into the space surrounding the fire.

It is an object of the present invention to provide a control knob in which one or more of the aforementioned drawbacks are alleviated.

According to a first aspect of the present invention there is provided a control knob adapted for mounting between a control means and an opening in an external wall of an appliance, for instance a gas fire, the knob comprising a finger grip portion rotatable about its axis and a co-operable cover portion having an aperture to receive the finger grip portion, and, in use on the appliance, the cover portion is movable relative to and along the axis of the finger grip portion from a first position to a second position against resilient means; in the first position the finger grip portion does not extend through the aperture beyond the cover portion and the external wall of the appliance to an extent which would enable the finger grip portion to be gripped and axially rotated without displacing the cover portion along said axis from the first position, in the second position the finger grip portion is exposed through the aperture and capable of being gripped and rotated on its axis to actuate the control means of the appliance.

Further according to the first aspect of the present invention there is provided an appliance including at least one control knob as described in the immediately preceding paragraph. Preferably, the cover portion is rotatable about said axis as the finger grip portion is gripped and rotated, and may be provided with a skirt in sliding engagement with the finger grip portion.

The cover portion covers part of the finger grip portion from view and preferably, on the appliance, extends across the opening to substantially cover the opening in the external wall. Preferably, the cover portion is arranged not to extend beyond the external wall and also so that in the first position, the cover portion, finger grip portion and external wall are flush and therefore appeal more readily to the eye.

Conveniently, where the appliance is a gas fire the control knob may be fitted in an opening in a top wall. Positioning the control knob on a top wall of a gas fire may render the knob less accessible to children than if positioned on the lower portion of a side wall.

Preferably, the knob comprises resilient means which may be in the form of a helically coiled compression spring, the finger grip portion and the cover portion each being of one piece construction, and at least one of the cover portion and finger grip portion being provided with an annular recess in which the spring is located.

Means such as a flange, may be provided on the finger grip portion to limit the axial movement of the cover portion as the cover portion is moved from the first to the second position. Alternatively such means could be provided on the appliance.

Similarly, means may be provided on the finger grip portion and/or on the appliance to limit the axial movement of the cover portion from the second to the first position.

The cover portion and finger grip portion are preferably made from plastics.

According to a second aspect of the present invention there is provided a control knob adapted for mounting between a control means and an opening in an external wall of an appliance, for instance a gas fire, the control knob comprising a cover portion mountable on and co-operable with a finger grip portion, the cover portion having an aperture to receive the finger grip portion and movable along the axis of the finger grip portion, resilient means mountable between the cover portion and the finger grip portion so that the cover portion is movable from a first position relative to the finger grip portion against resistance provided by the resilient means to a second position relative to the finger grip portion, means on at least one of the finger grip portion and cover portion to seat the resilient means against motion transverse to said axis; in the first position the finger grip portion does not extend beyond the aperture in a direction away from the resilient means and in the second position the finger grip portion is exposed through the aperture in said direction.

Further according to the second aspect of the invention there is provided an appliance including at least one control knob as described in the immediately preceding paragraph.

An embodiment of a control knob in accordance with the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows a diagrammatic perspective view of a gas fire including the control knob; Figure 2 shows an axial cross-sectional view of the control knob mounted between an opening in an external wall and a control spindle of the gas fire shown in Figure 1 , the control knob being in an 'Off' position; Figure 3 shows a view similar to Figure 2 in which the control knob has been rotated through 900 and is in an 'on' position; Figure 4 shows an enlarged view looking in the direction of arrow A in Figure 3, and Figure 5 shows an axial cross-sectional view of a modified control knob and which is similar to Figure 2.

Figure 1 shows a domestic gas fire 1 having a top external wall 2. A control knob 3 is located in a circular opening 4 (see Figure 2) at the right-hand end of the top wall 2.

Figures 2 and 3 show the control knob 1 in 'on' and 'off' positions respectively. The knob 1 is mounted between the top wall 2 and control means in the form of a control spindle 5, the knob being rotatable about the spindle axis Il-Il. In this instance the knob has been adapted for mounting between the opening 4 and control spindle 5 by the provision of an annular collar 6a on a circular cover portion 6 and by the provision of an axial bore 7a in a finger grip portion 7. The collar 6a is engageable with an inwardly directed skirt portion 2a on wall 2 which defines the opening 4 and the spindle 5 is shown fully inserted into the bore 7a.

Engagement of the collar 6a with skirt 2a limits the axially outward extent to which the cover portion is movable relative to the finger grip portion 7.

The cover portion 6 is top-hat shaped (the brim of the hat being constituted by collar 6a) and has a co-axial cylindrical internal skirt 6b extending axially inwardly of external wall 2 below the collar 6a.

As shown in Figures 1 to 3 the cover portion 6 substantially covers opening 4 and finger grip portion 7 and, as shown more clearly in Figure 1, is provided with a diametral slot to receive a flat elongate end 7b of the finger grip portion 7. The elongate end 7b is integral with a cylindrical middle portion 7c provided with a flange 7d and a generally semi-cylindrical axial extension 7e of substantially lesser diameter (see Figure 4). The bore 7a extends through extension 7e and into the cylindrical middle portion 7c. The diameter of portion 7c matches the internal diameter of skirt 6b, and skirt 6b is in sliding engagement with portion 7c.

The control knob 3 includes resilient means in the form of a helically coiled compression spring 8 arranged co-axially with the cover portion 6 and finger grip portion 7. One end of the spring is seated on flange 7d of the finger grip portion and the other end of the spring is seated in annular recess 9 in the cover portion 6 partially defined by skirt 6b. Recess 9 restrains movement of the spring transvers to axis Il-Il.

In operation the cover portion 6 is depressed axially from a first position shown in Figures 1 and 2 to a second position in which the end 7b of finger grip portion 7 is exposed. The end 7b is capable of being gripped substantially as the cover portion is depressed against resistance provided by the spring 8. The spring can be compressed until skirt 6b engages flange 7d which is substantially simultaneously as the cover portion 6 engages abutment face 7f of middle portion 7c.

The abutment face 7f and flange 7d limit the inward axial movement of the cover portion relative to the finger grip portion 7. The finger grip portion 7 may then be depressed slightly and rotated about axis Il-Il with the cover portion 6, to turn the control spindle and supply gas to a burner (not shown) of the gas fire 1. It is usual for the control spindle 5 to be prevented from rotating until it has been depressed slightly, for example, by 1 to 2 mm. On release of the finger grip portion 7 the cover portion is returned to its initial axial position relative to the cover portion by the spring 8.

The end 7b could be of any convenient shape. It could be cylindrical and the aperture in the cover portion 6 circular in which case it may be preferable for the cover portion to be nonrotatable with the finger grip portion. In the described embodiment the external wall 2, cover portion 6 and finger grip portion 7 present a flush appearance. If desired where the cover portion 6 is non-rotatable it could project outwardly from the external wall and may be of any suitable cross section, for example, of square cross section.

Means could be provided on the finger grip portion to limit the outward extent to which the cover portion is movable relative to the finger grip portion, for example, end 7b may be T-shaped and received in a T-shaped slot in the cover portion eliminating the need for skirt portion 2a.

Figure 5 shows a modified control knob 3 in which the outward extent to which the cover portion 6 is movable relative to the finger grip portion 7 is limited by screw heads 1 OA of screws 10 engaging flange 7d. The screws 10 have screw thread portions 1 Ob engaging a thickened skirt portion 6'b. The screws 10 may also act as an adjustment means to ensure correct positioning of the cover portion 6 with respect to the finger grip portion 7.

The control knob could be employed on other appliances, for example, a gas cooker and need not be adapted to be located on a central control spindle. The control knob may be adapted to any control means to control the flow of energy to an appliance.

Claims

1. A control knob adapted for mounting between a control means and an opening in an external wall of an appliance, for instance a gas fire, the knob comprising a finger grip portion rotatable about its axis and a co-operable cover portion having an aperture to receive the finger grip portion, and, in use on the appliance, the cover portion is movable relative to and along the axis of the finger grip portion from a first position to a second position against resilient means; in the first position the finger grip portion does not extend through the aperture beyond the cover portion and the external wall of the appliance to an extent which would enable the finger grip portion to be gripped and axially rotated without displacing the cover portion along said axis from the first position, in the second position the finger grip portion is exposed through the aperture and capable of being gripped and rotated on its axis to actuate the control means of the appliance.

2. A knob as claimed in Claim 1 in which, in use on an appliance, the cover portion is rotatable with the finger grip portion about said axis.

3. A knob as claimed in Claim 2 in which the aperture in the cover portion comprises a diametral slot which receives a flat end of the finger grip portion.

4. A knob as claimed in any one of the preceding claims in which the cover portion is provided with a skirt in sliding engagement with the finger grip portion.

5. A knob as claimed in one of the preceding claims which comprises resilient means in the form of a helically coiled compression spring, the finger grip portion and the cover portion each being of one piece construction and an annular recess in at least one of the cover portion and finger grip portion to seat the spring.

6. A knob as claimed in any one of the preceding claims in which means is provided on the finger grip portion to limit the axial inward movement of the cover portion as the cover portion is moved from the first to the second position.

7. A knob as claimed in Claim 6 in which the limiting means is a flange on the finger grip portion.

8. A knob as claimed in any one of the preceding claims in which means is provided on the finger grip portion to limit the axial movement of the cover portion from the second to the first position.

9. A knob as claimed in any one of the preceding claims in which the finger grip portion and cover portion are made from plastics.

10. A knob as claimed in Claim 1 and substantially as herein described with reference to Figures 1 to 4 of the accompanying drawings.

11. A knob as claimed in Claim 9 and modified substantially as herein described with reference to Figure 5 of the accompanying drawings.

12. A control knob adapted for mounting between a control means and an opening in an external wall of an appliance, for instance a gas fire, the control knob comprising a cover portion mountable on and co-operable with a finger grip portion, the cover portion having an aperture to receive the finger grip portion and movable along the axis of the finger grip portion, resilient means mountable between the cover portion and the finger grip portion so that the cover portion is movable from a first position relative to the finger grip portion against resistance provided by the resilient means to a second position relative to the finger grip portion, means on at least one of the finger grip portion and cover portion to seat the resilient means against motion transverse to said axis; a in the first position the finger grip portion does not extend beyond the aperture in a direction away from the resilient means and in the second position the finger grip portion is exposed through the aperture in said direction.

13. A knob as claimed in Claim 12 and substantially as herein described with reference to Figures 1 to 4 of the accompanying drawings.

14. A knob as claimed in Claim 13 and modified substantially as herein described with reference to Figure 5 of the accompanying drawings.

1 5. An appliance comprising at least one knob as claimed in any one of the preceding claims in which the knob is mounted between control means and an opening in an external wall of the appliance.

16. An appliance as claimed in Claim 15 in which the external wall, cover portion and finger grip portion exhibit a substantially flush appearance when the cover portion is in the first position.

17. An appliance as claimed in Claim 1 5 or Claim 16 in which the external wall is a top wall of the appliance.

18. An appliance as claimed in any one of Claims 1 5 to 1 7 in which the appliance is gas fired and has control means in the form of a control spindle operatively connected to said at least one control knob, the appliance being provided with means to limit axially outward movement of the cover portion relative to the finger grip portion as the cover portion is moved from the second to the first position.

1 9. An appliance as claimed in Claim 1 8 in which said axially outward limiting means comprises an inwardly directed skirt portion defining the aperture.

20. An appliance as claimed in Claim 13 and substantially as herein described with reference to Figures 1 to 4 of the accompanying drawings.

21. An appliance as claimed in Claim 19 and modified substantially as herein described with reference to Figure 5 of the accompanying drawings.