GB2365626A

GB2365626A - Switch operating mechanism

Info

Publication number: GB2365626A
Application number: GB0019401A
Authority: GB
Inventors: Peter Hallam Wright; Mark Richard Farlam
Original assignee: Otter Controls Ltd
Current assignee: Otter Controls Ltd
Priority date: 2000-08-07
Filing date: 2000-08-07
Publication date: 2002-02-20
Anticipated expiration: 2020-08-07
Also published as: AU2001276527A1; GB0019401D0; GB2365626B; WO2002013217A2; WO2002013217A3

Abstract

An operating mechanism comprises an operating member 4 which is coupled to the trip lever 3 of a steam sensor switch 2 and an actuator 10 for moving the operating member 4. The actuator 10 is movable transversely to the operating member and has an end portion which, when the actuator is depressed, moves into an aperture 6 in the operating member 4 where cams on the actuator co-operate with cam follower surfaces of the aperture 6. On one side of the aperture the cam on the actuator 10 is a simple inclined surface 13 for moving the operating member 4 in a first direction and on the other side of the actuator the cam is a pivotally mounted member 14 which is compliant for accommodating movement of the operating member 4 in the first direction but has only limited pivotal movement in the opposite direction. A first depression of the actuator 10 brings one of the cams into play to move the operating member 4 in a first direction and a second depression causes the other cam to come into play to move the operating member 4 back in the opposite direction.

Description

2365626 SWITCH OPERATING MECHANISMS

Field of the Invention:

This invention relates to a switch operating mechanism and will be described in the following by reference to operation of a steam control in or for a water boiling vessel, for switching of for reducing the power supply to a heating element of the vessel when water boils in the vessel, though the invention is capable of wider application.

Background of the Invention:

Steam controls as abovementioned are commonly provided in domestic kettles and hot water jugs and an exemplary steam control is described in GB-A-2 331 848, this being the steam control which we manufacture and sell as our Z5 steam control. We have identified a need to operate the Z5 steam control from a single push-button in the manner of a ballpoint pen, namely push for on and push again for off, but with the requirement that the Z5 must be able to operate in response to boiling of water in a kettle or jug without any interference ftom the push-button mechanism.

This latter requirement arises because the mechanism may be operated fTom 2 some distance, ic may be a remote operating mechanism, and may be heavy or stiff which might inhibit the action of the Z5 control.

SummM of the Invention;

The Z5 steam control has a trip lever forming part of an overcentre mechanism which is arranged to be moved between on and off positions by the response of a bimetallic actuator to exposure to hot steam. According to the present invention a push-button type mechanism for operating the trip lever of a Z5 control comprises a reciprocally movable operating member for engagement with the Z5 trip lever for moving the same in directions corresponding to its operational movements and an actuator reciprocally movable generally transversely to the direction of movement of the operating member for moving the same, the operating member and the actuator having first and second co-operating cam and cam follower means for moving the operating member in respective opposite directions in response to successive operations of the actuator in the same direction, and one of said cam and cam follower means being compliant so as to accommodate the operation of the other.

Described hereinafter is an exemplary embodiment of the present invention in which the operating member is arranged to slide in a plane generally parallel to the motion of the trip lever and is designed to be attached 3 to the trip lever. The operating member has an aperture defining earn follower faces which are spaced apart from each other in the direction of movement of the operating member so as to co-operate with cam means provided on the actuator for moving the operating member in respective opposite directions.

The actuator is mounted for movement transversely to the operating member and is designed to move into the aperture of the operating member when it (the actuator) is operated. Cam surfaces on opposite sides of the actuator co-operate with respective ones of the cam follower faces on the aperture in the operating member and one of these cam surfaces is a simple inclined surface such as to engage and drive the operating member in a first direction when the actuator is depressed. The other cam surface is defined by a earn member which is movably mounted on the actuator so that, as the first-mentioned cam surface (the simple inclined surface) drives the operating member across the path of the actuator, the movably mounted earn member moves so as to accommodate this movement. When, after completion of this operating phase, the actuator is released and returns under spring loading to its original position, the movable cam member also returns to its original position. When the actuator is next depressed, with the operating member in the position to which it has been moved by the first-abovementioned cam surface (the simple inclined surface), the movable cam member now is in a position to engage with and move the operating member in an opposite direction.

4 It is ensured that the thus described trip lever operating mechanism does not interfere with normal operation of the steam sensor simply by arranging that the aperture in the operating member is such that when the actuator is in its return (not depressed) position the operating member has no contact with the actuator throughout the full range of movement of the trip lever.

The above and further features of the present invention are set forth in the appended claims and will be well understood from consideration of the following detailed description of an exemplary embodiment which is illustrated in the accompanying drawings.

Description of the Drawings:

Figure 1 is a schematic diagram illustrating the hereinafter described embodiment in rest condition with the accompanying Z5 control in switched off condition; Figure 2 shows a first stage in the depression of the push-button of the Figure 1 embodiment; Figure 3 shows the Figure 1 embodiment with the push-button fully depressed and the Z5 control switched on; Figure 4 shows the condition of the embodiment when the push-button is released fTom the Figure 3 condition; Figure 5 shows the push-button again being depressed; and Figure 6 shows the push-button again released and the Z5 again in off condition.

Detailed Description of the Embodiment:

Referring to the drawings, it is first to be understood that the arrangement shown is schematic rather than representing a commercial product. However, the arrangement shown is considered sufficient to enable a full and complete understanding of the invention.

Figure 1 shows the operating mechanism 1 associated with a Z5 steam control 2 having a trip lever 3. An operating member 4 is coupled to the trip lever and is slidable in a plane parallel to the general operating movement of the trip lever as is indicated by the double-headed arrow 5. An aperture 6 is provided in the operating member 4 and defines spaced-apart cam follower surfaces 7 and 8. Note also the formation 9 in the upper surface of the operating member 4; the purpose of this will become clear from the following.

A push-button actuator 20 is mounted to be reciprocally movable transverse to the plane of movement of the operating member 4 in the direction of the double-headed arrow 11, and has associated therewith a return spring 12. The lower end of the actuator 10 is arranged to penetrate the aperture 6 in the operating member 4 when the actuator is depressed.

6 On one side (the lefthand side as viewed in the drawings) of the lower end of the actuator 10 there is provided an inclined cam surface 13 which is designed to co-operate with the left-hand edge of the aperture 6 in the operating member 4, namely with the cam follower surface 7, for the purpose of driving the operating member leftwardly as the actuator is depressed. On the other (right-hand) side of the lower end of the actuator 10 there is provided a compliant cam arrangement 14 which is designed to accommodate leftwards movement of the operating member 4 on a first depression of the actuator 10 and to drive the operating member 4 rightwardly on a succeeding depression of the push-button actuator 10. In the illustrated embodiment, the compliant cam arrangement 14 comprises a shaped cam member which is pivotally mounted to the actuator 10 at the point 15 and is shaped to co-operate with various of the surfaces of the arrangement as will be described hereinafter and otherwise to find its own position gravitationally. The cam member 14 is capable of a substantial amount of clockwise rotation, but its anti- clockwise rotation is limited by engagement of a nose portion 16 of the cam member with a stop 17 provided at the bottom end of the push-button actuator 10.

Figure 1 shows the arrangement with the push-button actuator 10 at the top of its upwards movement, the operating member 4 at the furthest extent of its rightwards movement and the trip lever 3 in the off position of the Z5 steam switch 2. Note that in this position the actuator 10 does not 7 inhibit free movement of the operating member 3 or correspondingly of the trip lever 3.

Figure 2 shows how as the push-button actuator 10 is depressed, its lower end enters the aperture 6 in the operating member 4 and the cam surface 13 of the actuator contacts cam follower surface 7 of the operating member 4 so as to drive it (the operating member) to the left as the actuator is further depressed. Note that the position of the cam member 14 does not prevent depression of the actuator 10.

Figure 3 shows the push-button actuator 10 fully depressed, the operating member 4 at its most leftwards position and the trip lever 3 of the Z5 control 2 tripped to its opposite switching condition. Note that the cam member 14 rotates clockwise to accommodate the leftwards movement of the operating member 4.

Figure 4 shows the condition of the arrangement after the actuator 10 has been released and returns to its uppermost position under action of the spring 12. Note that the cam member 14 has rotated anti-clockwise to its original (Figure 1) position either under the action of gravity or by the action of a return spring (not shown).

Figure 5 shows what happens when the push-button actuator 10 is again depressed. The moving cam member 14 having rotated anti-clockwise until its nose portion 16 encounters the stop 17, depression of the actuator 10 causes the cam member 14 to engage cam follower surface 8 of the operating 8 member 4 and drive it rightwards. However, the extent to which it is moved during downwards travel of the actuator 10 is limited by engagement of a hook formation 18 on the cam member 14 (see Figure 4) with the formation 9 that is provided on the operating member 4. This arrangement ensures that any excessive force applied to the push-button actuator 10 is resisted by the cam member 14 and the engagement of its nose portion 16 with the stop 17, these parts being made as robust as may be necessary to withstand the forces to which they are subjected. The limited movement afforded to the operating mechanism 4 is sufficient to move the trip lever 3 overcentre, but then holds it at this position until, as shown in Figure 6, the actuator 10 is released and the arrangement returns to its Figure 1 condition.

If the trip lever 3 were to be in its Figure 3 position when the actuation is first depressed, the operations described in the foregoing with reference to Figures 4, 5 and 6 would set the trip lever into its alternative condition.

The invention having thus been described in the foregoing by reference to a particular embodiment, it is to be well understood that the embodiment is in all respects exemplary and that modifications and variations thereto could be made without departure from the spirit and scope of the invention. For example, the invention is not limited to the use of a Z5 steam control or even to a steam control, the mechanism of the invention being seen as having wider application. Also, for applications requiring operation of a switch from two different positions, it being appreciated that the actuator 10 in 9 the described embodiment could be remotely operated (for example by means of a Bowden cable), there could be provided two operating members associated with the switch with each operating member having its own actuator located at a specific location. The switch could of course also be locally operable, for example in the embodiment described by provision of a rocker knob coupled with the Z5 trip lever.

Claims

Claims:

1. An operating mechanism comprising an operating member which is reciprocally movable in a first direction and an actuator which is reciprocally movable in a direction transverse to said first direction, the operating member and the actuator having first and second co-operating cam and cam follower means for moving the operating member in respective opposite directions in response to successive operations of the actuator in the same direction, and one of said cam and cam follower means being compliant so as to accommodate the operation of the other.

2. A mechanism as claimed in claim 1 wherein the actuator is spring loaded so that when released it returns to a position whereat it does not interfere with movement of the operating member.

3. A mechanism as claimed in claim 1 or 2 wherein the operating member has a part defining first and second spaced-apart cam follower surfaces and the actuator has a portion arranged to move between said cam follower surfaces when the actuator is operated, such portion having first and second cam means thereon for co-operation with respective ones of said cam follower surfaces.

11

4. A mechanism as claimed in any preceding claim wherein the compliant means comprises a cam member which is pivotally mounted on the actuator, the cam member being capable of substantial pivotal movement in a first direction corresponding to the direction of movement caused to the operating member by the action of a second cam means provided on the actuator and being limited as regards its pivotal movement in the opposite direction, the cam member thus being compliant to accommodate movement of the operating member in said first direction and serving to drive the operating member in said opposite direction.

5. A mechanism substantially as herein described with reference to the accompanying drawings.

6. A mechanism as claimed in any of the preceding claims in operative combination with a switch, the operating member of the mechanism being coupled to an operating member of the switch whereby the switch can be operated by means of said actuator.

7. A combination as claimed in claim 6 wherein the switch is a steam sensor switch in or for a water boiling vessel.