GB2253094A

GB2253094A - Interlocking mechanism for an electrical appliance

Info

Publication number: GB2253094A
Application number: GB9200500A
Authority: GB
Inventors: Henry Greaves; Kenneth Henry Grange
Original assignee: Kenwood Marks Ltd
Current assignee: Kenwood Marks Ltd
Priority date: 1991-01-11
Filing date: 1992-01-10
Publication date: 1992-08-26
Anticipated expiration: 2012-01-10
Also published as: GB2253094B; GB9100587D0; GB9200500D0

Abstract

An interlocking mechanism for an electrical appliance 1, having a lid 2 with a projection 3, comprises interlocking means 8, 9 engaging with a rotary switch member 6 and for cooperating with the lid projection 3 to secure the lid 2 in its closed position. The interlocking means 8, 9 comprise two longitudinal members having detents 12, 13 which engage in slots 14, 15 respectively in the switch member 6, and one 8 of the interlocking members 8, 9 is pivotable to engage with the lid projection 3. By this arrangement, the interlocking members 8, 9 inhibit rotation of the switch member 6 unless the lid 2 is secured in its closed position by interlocking member 8. The switch member 6 is rotatable to connect power to the appliance 1 once the lid 2 is secured in its closed position and also to actuate the interlocking means 8, 9 to release the lid 2 after power to the appliance 1 has been disconnected. <IMAGE>

Description

INTERLOCKING MECHANISM FOR AN ELECTRICAL APPLIANCE This invention relates to an interlocking mechanism for an electrical appliance of the type having a lid, or other closure member, in which it is desirable to ensure that the lid is securely closed before power can be supplied to the appliance.

Such mechanisms are particularly applicable in domestic electrical appliances such as food processors and juice extractors, which can be dangerous if access to any moving parts is possible whilst the appliance is in operation.

Known food processors, having a lid which is closed and opened by rotation thereof, are generally provided with a mechanical interlocking mechanism in order to ensure that the lid is locked in its closed position before the food processor can be actuated. In this mechanism, a spring-loaded pivotable interlock member engages with a rotary switch actuator to inhibit rotation of the actuator, and the interlock is pivoted out of engagement with the actuator by rotation of the lid into its closed position.

The actuator can then be rotated to switch the appliance on and off. However, once the actuator has been returned to the off position after use of the food processor, the lid must then be manually rotated to release it and to reengage the interlock with the actuator. Additionally, as operation of this mechanism relies on rotation of the lid, it cannot be used in conjunction with vertically-fitted, non-rotatable lids, which may be used, for example, on juice extractors.

Interlocking mechanisms which can be used with vertically-fitted, non-rotatable lids are known. However, they generally require the provision of a microswitch which is triggered by closing of the lid to enable power to be supplied to the appliance.

It is therefore an object of the present invention to provide an interlocking mechanism, which can be operated more simply than known mechanisms of this kind and which can be used with vertically-fitted, non-rotatable lids without the need for a microswitch.

Thus, the present invention consists in an interlocking mechanism for an electrical appliance having a closure member, said mechanism comprising interlocking means engaging with a rotary switch member and for cooperating with the closure member to secure said closure member in its closed position, said interlocking means being arranged to inhibit rotation of said switch member unless the closure member is secured in its closed position by said interlocking means, said switch member being rotatable to connect power to the appliance once the closure member is secured in its closed position and also to actuate the interlocking means to release the closure member after power to the appliance has been disconnected.

In a preferred embodiment, the rotary switch member is provided with at least three operating positions, a first position to connect power to the appliance after the closure member is secured in its closed position, a second position to disconnect the power, and a third position to actuate the interlocking means to release the closure member. In order to ensure that the power is disconnected before the closure member is released, the switch member may be rotated in one direction to its first position and then rotated in the opposite direction to the second position and further rotated in the same direction to the third position. The switch member may have an additional position determined by further rotation of the switch member in said one direction so as to provide a two-speed operation of the appliance.

The interlocking means preferably comprises two longitudinal members. A first one of said longitudinal members is preferably pivotally mounted in a central region thereof and has an engaging member, for example a detent, located at one end thereof, which engages with the rotary switch member, and the other end of the first interlocking member is arranged to co-operate with the closure member.

The second longitudinal member is preferably constrained to move along its longitudinal axis and also has an engaging member, for example a detent, located at one end thereof which engages with said rotary switch member, and its other end is arranged to co-operate with said closure member.

Advantageously, both interlocking members are resiliently mounted.

The engaging members may engage, and be movable, in respective slots formed in the rotary switch member, the slots being shaped to provide abutment surfaces against which the engagement members engage in order to inhibit rotation of the switch member.

The first interlocking member may be provided with a flange arranged to co-operate with another flange provided on a projection of the closure member in order to secure the closure member in its closed position. The flanges may have generally parallel oblique end surfaces which slide relative to each other to effect pivotal movement of the first interlocking member and thus movement of the engaging member of said first interlocking member in the slot of the switch member in which it is engaged.

The second interlocking member may be arranged to be moved along its longitudinal axis by abutment with the projection of the closure member, thereby causing the engaging member of the second interlocking member to move in the slot of the switch member in which it is engaged.

In order that the present invention may be more readily understood, reference will now be made by way of example to the accompanying drawings, in which: Fig. 1 is a diagrammatic view of an interlocking mechanism according to one embodiment of the invention; and Figures 2 to 6 show various different positions of the mechanism of Figure 1.

Referring firstly to Figure 1, an electrical appliance 1 has a lid 2 having a projection 3 terminating in a flange 4 having an oblique end surface 5. A switch member 6 is pivotally mounted for rotation about an axis 7, by means of, for example, a rotary control (not shown) located on the outside of the appliance to switch power to the appliance. Interlocking means consist of two longitudinal interlocking members 8 and 9. Interlocking member 9 is constrained to move along its longitudinal axis and is resiliently biased towards the lid projection 3. Interlocking member 8 is mounted for pivotal movement about an axis 11 and is resiliently biassed in an anti-clockwise direction as shown. Adjacent ends 8a,9a of the interlocking members 8,9 have detents 12,13 which respectively engage in slots 14,15 in the switch member 6.The other end 8b of the interlocking member 8 has a flange 16 extending generally perpendicular to the longitudinal axis of the interlocking member 8 and terminating in an oblique end surface 17, which is generally parallel to the end surface 5 of flange 4. The slots 14,15 of the switch member 6 are shaped so as to provide a plurality of abutment surfaces for the detents 12,13 as will be described hereinbelow.

Various stages of operation of the interlocking mechanism are shown in Figures 1 to 6.

In Figure 1, the lid 2 is in an open position above the appliance and the detent 13 abuts against abutment surface 15a of slot 15 in order to inhibit rotation of the switch member 6 in a clockwise direction to switch power to the appliance. As the lid 2 is moved closer to the appliance, as shown in Figure 2, oblique end surface 5 slides along oblique end surface 17 which pivots the interlocking member 8 against its bias, thereby moving the detent 12 into engagement with abutment surface 14a of slot 14. At the same time, the lid projection 3 pushes the interlocking member 9 against its bias towards the pivot axis 7 of the switch member 6 and out of engagement with abutment surface 15a.Thus, although the detent 13 is now out of engagement with an abutment surface, the detent 12 engages with the abutment surface 14a, so that rotation of the switch member 6 in a clockwise direction to switch power to the appliance is still inhibited.

In Figure 3, the lid 2 is now in a closed position on the appliance, in which the oblique end surface 5 has moved past the end surface 17 and the interlocking member 8 pivots back to its initial position under the action of its resilient bias. The flange 16 thus overlies the flange 4, thereby securely retaining the lid 2 in its closed position. In this position, neither detent 12 nor 13 is engaged with an abutment surface, and the switch member 6 can be rotated. In Figure 3, in order to switch power to the appliance, the switch member 6 is rotated through about 300 clockwise to activate the motor (not shown) of the appliance to operate at a predetermined speed and the detents are located in the middle regions of the slots 14,15.

In Figure 4, the switch member 6 has been rotated through a further 300 clockwise to a second motor speed position. Both detents 12,13 are now engaged with abutment surfaces 14b,15b, which inhibits any further clockwise rotation of the switch member 6.

In order to switch off the motor and release the lid, the switch member 6 is rotated through 900 anti-clockwise to the position in Figure 5. In this position, neither detent 12, 13 is engaged against an abutment surface, but the flange 16 still slightly overlies the flange 4 to hinder removal of the lid 2. However, as the switch is rotated anti-clockwise by a further 300, as shown in Figure 6, the detent 12 moves along slot surface 14c, which pivots the interlocking member 8 away from the flange 4, until the detent 12 engages with end abutment surface 14d of the slot 14. The lid 2 is then free to be lifted from the appliance, so that interlocking member 9 moves away from the switch pivot axis 7 under the action of its bias, which causes the detent 13 to engage with an abutment surface 15c of the slot 15.In this position, the switch member 6 is hindered from rotating any further in the anti-clockwise direction. The switch member 6 can then rotate back clockwise to its initial position, thereby pivoting the interlocking member 8 also to its initial position and returning the detent 13 to abut with the slot surface 15a, as shown in Figure 1.

The interlocking mechanism may be utilised in any electrical appliance for which it is desirable, particularly for safety purposes, to ensure that a closure member or lid of the appliance is secured in its closed position before power is supplied to the appliance. However, it is particularly suitable for use in a small domestic electrical appliance, such as a juice extractor or food processor.

It can thus readily be envisaged that the mechanism, in accordance with the described embodiment of the present invention, uses a single rotary switch to connect and disconnect power to the appliance and also to release the lid, thus avoiding the need for a microswitch, as well as also simplifying operation of the mechanism. The construction of the mechanism is also simple and completely mechanical, which makes it easier and cheaper to manufacture and assemble in the appliance.

Whilst one embodiment of the invention has been described, it will be appreciated that modifications may be made without departing from the scope of the invention.

Claims

1. An interlocking mechanism for an electrical appliance having a closure member, said mechanism comprising interlocking means engaging with a rotary switch member and for co-operating with the closure member to secure said closure member in its closed position, said interlocking means being arranged to inhibit rotation of said switch member unless the closure member is secured in its closed position by said interlocking means, said switch member being rotatable to connect power to the appliance once the closure member is secured in its closed position and also to actuate the interlocking means to release the closure member after power to the appliance has been disconnected.

2. An interlocking mechanism as claimed in claim 1, wherein the rotary switch member is provided with a first operating position to connect power to the appliance after the closure member is secured in its closed position, a second operating position to disconnect the power, and a third operating position to actuate the interlocking means to release the closure member.

3. An interlocking mechanism as claimed in claim 2, wherein the switch member is rotatable in one direction to the first operating position and then rotatable in the opposite direction to the second operating position and further rotatable in the same direction to the third operating position, thereby ensuring that the power is disconnected before the closure member is released.

4. An interlocking mechanism as claimed in claim 3, wherein the switch member has an additional operating position determined by further rotation of the switch member in said one direction so as to provide a two-speed operation of the appliance.

5. An interlocking mechanism as claimed in any preceding claim, wherein the interlocking means comprises a first longitudinal interlocking member pivotally mounted in a central region thereof and having an engaging member, located at one end thereof, which engages with the rotary switch member, and the other end of the first interlocking member is arranged to co-operate with the closure member.

6. An interlocking mechanism as claimed in claim 5, wherein the interlocking means comprises a second longitudinal interlocking member constrained to move along its longitudinal axis and having an engaging member, located at one end thereof, which engages with said rotary switch member, and its other end is arranged to co-operate with said closure member.

7. An interlocking mechanism as claimed in claims 5 and 6, wherein both interlocking members are resiliently mounted.

8. An interlocking mechanism as claimed in claim 5,6 or 7, wherein the or each engaging member engages, and is movable, in a slot formed in the rotary switch member, the or each slot being shaped to provide abutment surfaces against which the engaging member abuts in order to inhibit rotation of the switch member.

9. An interlocking mechanism as claimed in any one of claims 5 to 8, wherein the first interlocking member is provided with a flange arranged to co-operate with another flange provided on the closure member in order to secure the closure member in its closed position.

10. An interlocking mechanism as claimed in claim 9, wherein the flanges have generally parallel oblique end surfaces which slide relative to each other to effect pivotal movement of the first interlocking member and thus movement of the engaging member of said first interlocking member in the slot of the switch member in which it is engaged.

11. An interlocking mechanism as claimed in any one of claims 6 to 10, wherein the second interlocking member is arranged to be moved along its longitudinal axis by abutment with the closure member, thereby causing the engaging member of the second interlocking member to move in the slot of the switch member in which it is engaged.

12. An interlocking mechanism substantially as herein described with reference to the accompanying drawings.

13. An electrical appliance having a closure member and including an interlocking mechanism as claimed in any preceding claim.