GB2331148A - Rotary actuator - Google Patents

Abstract

A rotary actuator arrangement, for example as illustrated in Figure 3, comprises an actuator member 12 mounted upon a housing 10. The member 12 includes at least one integral, resilient flexible part 20 biased by the inherent resilience of the actuator member 12 into engagement with the housing 10 to resist movement of the actuator member 12 relative to the housing 10. As a result, improved user feedback can be achieved and undesirable adjustment of the actuator arrangement can be resisted.

Description

ROTARY ACTUATOR This invention relates to a rotary actuator suitable for use in, for example, controlling the operation of an air vent in a vehicle ventilation system. It will be appreciated that the actuator is also suitable for use in other applications.

When such an actuator is used to control the operation of an air vent, it is known to transmit rotary motion of the actuator to the operating mechanism of the vent either by way of rotary motion or by way of the movement of a push rod. It is convenient for there to be a certain amount of resistance to movement of the actuator as this provides a positive feedback for the user and can also reduce undesirable adjustment of the vent resulting from, for example, vehicle vibration.

Such resistance to movement can be achieved using the inherent friction within the operating mechanism. However, a more consistent level of resistance can be achieved by modifying the actuator.

In a known arrangement, the actuator is mounted upon a vent housing in a rotary manner, for example by means of a screw. The actuator carries a separate, rigid, friction plate which is resiliently biased into engagement with the vent housing. In order to rotate the actuator relative to the vent housing, the friction plate must slide over the surface of part of the vent housing, and the friction therebetween acts to resist such movement of the actuator providing the positive feedback.

Although such an arrangement achieves a reasonably consistent level of resistance to movement, the arrangement is composed of several parts and is relatively time consuming to assemble and relatively expensive. It is an object of the invention to provide a rotary actuator of relatively simple form.

According to the present invention there is provided a rotary actuator arrangement comprising an actuator member rotatably mounted upon a housing, at least one integral, flexible part of the actuator member being biased, by the inherent resilience of the actuator member, into engagement with the housing, and means whereby movement of the actuator is transmitted to an operating mechanism.

It will be appreciated that the positive feedback is achieved, in this arrangement, by the engagement of the flexible part or parts of the rotary actuator with the housing. Clearly, the arrangement is advantageous in that a reduced number of components are present resulting in assembly of the arrangement being simplified. Further, it has been found that the feedback produced from this arrangement is more consistent than when a separate, rigid friction plate is used.

The actuator member is conveniently provided with a projection receivable, in a snap fit manner, in an opening provided in the housing to rotatably mount the actuator member upon the housing. Alternatively, a projection may be provided on the housing, the projection being received in an opening provided in the actuator member.

The housing conveniently comprises a vent housing of part of a vehicle ventilation system.

The invention further relates to an actuator member of the type described hereinbefore and suitable for use in such an actuator arrangement.

The invention will further be described, by way of example, with reference to the accompanying drawings, in which Figure 1 is a view of an actuator arrangement in accordance with an embodiment of the invention; Figure 2 is a sectional view along the line 2-2 of Figure 1 ; and Figure 3 is an isometric view of the section illustration in Figure 2.

Figure 1 illustrates part of a vent assembly for use in the ventilation system of a vehicle which comprises a vent housing 10 upon which a rotary actuator member 12 is rotatable mounted as described hereinafter.

The vent housing 10 conveniently includes a plurality of vanes which are adjustable in order to direct the flow of air through the vent housing 10 and, additionally, valve means operable under the control of an operating mechanism to control the rate of air flow through the vent housing.

The rotary actuator member 12 is of generally circular form, and is provided with a projection 14 which is arranged to extend through an opening 16 provided in a side wall of the vent housing 10. The projection 14 is provided, at its free end, with an outwardly extending flange 18 which is intended to engage the rear surface of the side wall, the projection 14 being split so as to permit the actuator member 12 to be secured to the vent housing in a snap-fit manner. It will be appreciated that, once mounted upon the vent housing 10, the engagement of the flange 18 with the rear surface of the side wall prevents or restricts removal of the actuator member 12.

The projection 14 defines a central hub of the actuator member 12, and integral with the hub are a pair of flexible regions 20 which are angled with respect to the plane of the remainder of the actuator member 12, and orientated such that, when mounted upon the vent housing 10 as described hereinbefore, the flexible regions 20 engage the outer surface of the side wall of the vent housing 10. The inherent resilience of the material forming the actuator member 12 is such as to ensure that when the actuator member 12 is secured to the vent housing 10, the flexible regions 20 remain in contact with the outer surface of the side wall of the vent housing 10 during subsequent movement of the actuator member 12, the friction between the regions 20 and the side wall of the vent housing 10 acting to resist angular movement of the actuator member 12 with respect to the vent housing 10.

The hub of the actuator 12 is further integral with a pair of spokes 22 which connect an outer rim 24 to the hub. The outer rim includes a region which, in use, extends to the front of the vent housing and is intended to be moved by a user, in use, in order to adjust the operation of the vent. This part of the rim 24 is conveniently composed of a material which is soft to the touch, and is conveniently formed with a plurality of grooves or other formations in order to assist a user in gripping the actuator member 12.

The actuator member 12 further comprises a pair of formations 26 which are arranged to receive, in a snap-fit manner, a push rod (not shown) which interconnects the actuator member 12 with the operating mechanism of the valve of the vent to transmit movement of the actuator member 12 to the operating mechanism. The rim 24 further carries a stop member 28 which is arranged to engage formations formed, for example, on the side wall of the vent housing 10 in order to limit the maximum range of angular movement of the actuator member 12 which is permitted. The stop member 28 and the location of the formations on the side wall of the vent housing 10 are intended to define fully open and fully closed positions of the vent.

As shown most clearly in Figures 2 and 3, the outer surface of the side wall of the vent housing 10 is provided with an annular wall 30, a similar annular wall 32 being formed on the side of the rim 24 which faces the side wall of the vent housing 10, the annular walls 30, 32 being arranged to cooperate with one another to assist in maintaining the location of the actuator member 12 with respect to the side wall of the vent housing 10, in use.

In use, in order to adjust the operation of the vent, the user adjusts the angle of the actuator member 12, this movement being transmitted through the pushrod to the operating mechanism. It will be appreciated that adjustment of the position of the actuator member 12 causes the flexible regions 20 to slide over the outer surface of the side wall of the vent housing 10 and, additionally, the flange 18 slides over part of the rear surface of the side wall. The friction between the side wall and the parts of the actuator member 12 in engagement therewith opposes such movement and provides a positive feedback to the user.

The vent housing 10 and actuator member 12 are conveniently formed using appropriate injection moulding processes, the vent housing 10 and actuator member 12 conveniently being composed of suitable plastics materials. Although the actuator member 12 is a single component, it may be appropriate to form the actuator member 12 using an injection moulding process of the type in which different materials are injected into different parts of the mould to form a unitary product with different parts of the product being formed of different materials and hence having different properties.

It will be appreciated that assembly of the actuator member described hereinbefore is simple as all that is required is for the actuator member 12 to be secured to the vent housing 10 by means of introducing the projection 14 into the opening 16, and pushing the actuator member 12 fully home, the actuator member 12 being secured in position by means of the snap-fit arrangement. Once the actuator member 12 is secured in position, the actuator member 12 can be connected to the operating mechanism by connecting the pushrod to one of the formations 26.

As the actuator member 12 takes the form of a single component, it will be appreciated that the assembly process is simplified significantly compared to the assembly process required for the multi-part construction of the prior art arrangements. Further, as the actuator member 12 includes flexible parts 20 rather than a rigid friction plate as in the prior art constructions, a more consistent level of feedback is achieved than in the known constructions.

Although the description hereinbefore is of an arrangement including two flexible regions, it will be appreciated that a single such region could be provided. Also, arrangements are possible which include more than two such regions. In another modification, the projection 14 may be an integral part of the side wall of the vent housing 10, the actuator member 12 including a central opening through which the projection extends to secure the actuator member 12 to the vent housing 10. In a further alternative, the projection 14 may be omitted and the actuator member 12 secured to the vent housing 10 using an alternative technique, for example using a screw.

Claims (10)

1. CLAIMS 1. A rotary actuator arrangement comprising an actuator member rotatably mounted upon a housing, at least one integral, flexible part of the actuator member being biased, by the inherent resilience of the actuator member, into engagement with the housing, and means whereby movement of the actuator is transmitted to an operating mechanism.
2. 2. An arrangement as claimed in Claim 1, wherein the actuator member includes two such flexible parts.
3. 3. An arrangement as claimed in Claim 1 or Claim 2, wherein the actuator member is provided with a projection receivable, in a snap-fit manner, within an opening provided in the housing to rotatably mount the actuator member upon the housing.
4. 4. An arrangement as claimed in Claim 1 or Claim 2, wherein the actuator member is provided with an opening arranged to receive a projection provided on the housing to rotatably mount the actuator member upon the housing.
5. 5. An arrangement as claimed in any one of the preceding claims, wherein the actuator member and the housing are shaped to define annular walls which are arranged to cooperate with one another to assist in maintaining the actuator member in the correct location relative to the housing.
6. 6. An arrangement as claimed in any one of the preceding claims, wherein the housing comprises a vent housing forming part of the ventilation system of a vehicle.
7. 7. An arrangement as claimed in any one of the preceding claims, wherein the actuator member takes the form of a plastics injection moulding.
8. 8. An arrangement as claimed in Claim 7, wherein the injection moulding process involves constructing at least two regions of the actuator member from different materials.
9. 9. An actuator member adapted for use in the actuator arrangement of any of the preceding claims.
10. 10. A rotary actuator arrangement substantially as hereinbefore described with reference to the accompanying drawings.