GB1600425A

GB1600425A - Motor vehicle rear-view mirrors

Info

Publication number: GB1600425A
Application number: GB377678A
Authority: GB
Original assignee: Desmo Ltd
Current assignee: Desmo Ltd
Priority date: 1978-05-25
Filing date: 1978-05-25
Publication date: 1981-10-14

Description

(54) IMPROVEMENTS RELATING TO MOTOR VEHICLE REAR-VIEW MIRRORS (71) We, DESMO LIMITED, a British Company of North Court, Packington Park, near Meriden, Warwickshire, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to rear view mirrors for motor vehicles of the kind comprising a housing in relation to which the reflective element is adjustable to enable the driver to obtain the required rear view. The reflective element is mounted in the housing by a central ball or equivalent adjustable joint. The housing is often in the form of a cowl with a rim extending beyond the edge of the reflective element.

With rear view mirrors of the kind described vibration of the reflective element can be a problem and it is an object of the present invention to provide means of reducing this vibration.

The present invention consists in a rear view mirror for a motor vehicle having a housing adapted to be secured to the vehicle and a reflective element mounted within the housing by an adjustable joint which enables the reflective element to be adjusted in relation to the housing to alter the rear view wherein damping means comprises, angularly spaced around the adjustable joint, spring-loading arms anchored to the reflective element or the housing and each making slidable frictional engagement with an associated guide in unity with the housing or the reflective element respectively, the arrangement being such that the spring loaded arms and the guides are constrained to remain in interengagement and to relative arcuate movement about the adjustable joint in the direction of movement of the reflective element with respect to the housing which occurs during adjustment of the reflective element to alter the rear view.

The frictional - engagement of the springloaded arms with the guides assists in retaining the reflective element in an adjusted position and in damping vibration. The constraint imposed upon the spring-loaded arms not only maintains each arm in engagement with its associated guide but prevents angular movement of the reflective element about an axis normal to its reflective surface. This is of particular advantage in a rear view mirror which has a reflective element with an oblong or other non-circular shape since the reflective element is held in correct relation to the surrounding rim of the housing.

The invention is applicable to mirrors in which the reflective element is directly manually adjustable and to those in which remote control of the adjustment is provided.

The guides preferably have grooves in which the spring loaded arms slide, the grooves being curved around the adjustable joint. In the case of a rear-view mirror having an adjustable joint with a single centre, a ball joint for example, the arcuate grooves are preferably concentric with the adjustable joint so that no force is imposed by the spring loaded arms which tends to move the reflective element about the adjustable joint. The springloaded arms may conveniently be of spring strip and each anchored at one end to the back of the reflective element. The guides may be formed as part of a mounting plate, diecast in light alloy or moulded in plastics, secured to the housing and forming a support for the adjustable joint. The guides may be limbs extending towards the back of the reflective element, of part-spherical shape and concentric with the adjustable joint and having grooves on their inner, concave surfaces. The grooves may be slightly wider than the spring strip of the arms to allow the arms to assume positions somewhat oblique to the limbs in the course of adjustment of the reflective element. Because of the need for such oblique movements, in another form of the invention the spring arms are furnished with roundheaded rivets which engage guide grooves of complementary, part-circular cross-section.

In a further modification each spring-loaded arm is formed by a hairpin shaped wire spring, the prongs of which slidably engage the associated guide by which they are embraced.

The spring-loaded arm is anchored at the bend of its hairpin shape and the prongs of the hairpin shape are curved and parallel to one another at least at the portions which slidably engage the associated guide.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which, Figure 1 is an elevation of a vehicle rear view mirror according to the invention but with the reflective element removed; Figure 2 is a section on line 2-2 of Figure 1; Figure 3 is a section on line 3-3 of Figure 1; Figure 4 is a section on line 4-4 of Figure 2; Figure 5 is a fragmentary section similar to Figure 2 Of a modified rear view mirror; Figure 6 is an underside plan view of a spring-loaded arm component of the mirror of Figure 5; Figure 7 is a fragmentary section of a further modification; and Figure 8 is a fragmentary section of another modification.

The vehicle rear-view mirror of Figures 1 to 4 is a remote control mirror intended to be fitted to the outer panel of a car door. The mirror comprises a cowl shaped housing 10 mounted by a yieldable joint 11 on a plinth 12 to be secured to the vehicle body. A reflective element 13 in a carrier 14 is mounted by an adjustable joint 15 on a mounting plate 16 rigidly secured inside the cowl of the housing.

The housing 10 and plinth 12 are in this instance die-castings in light alloy but they could be made in other material, plastics for example. The yieldable joint 11 allows the housing to deflect if struck but normally holds the housing in a predetermined attitude with respect to the plinth and the vehicle. The joint has a bore which allows sheathed flexible cable 17 for the remote control of the reflective element to pass from the housing, through the plinth into the vehicle body to a manual control. The yieldable joint 11 and the remote control form no part of the present invention and will not be further described.

The cowl of the housing 10 has an oblong rim 18 which surrounds the similarly shaped periphery of the reflective element 13. The carrier 14 is a sheet metal pressing and the reflective element 13 is suitably secured to it, by adhesive for example. The adjustable joint 15 is a ball joint, and comprises a socket 19 secured by a rivet 20 to the carrier 14 and a ball 21 snap-engaging the socket, and riveted by its shank 22 to the centre of the mounting plate 16. The mounting plate 16 is rigidly mounted within the cowl on pillars 23 projecting from the back of the housing 10. The mounting plate is a light alloy die casting and includes sockets 24 for the ends of the sheaths of the control cables 17 and the carrier 14 has nipples 25 in which the ends of the inner cables are secured, for example by crimping and/or soldering.

Three equally angularly spaced limbs 26 extending from the centre of the mounting plate provide points of attachment of the mounting plate to the pillars 23. Beyond the pillars the limbs are curved back towards the reflective element in part-spherical guide portions 27 concentric with the ball. Grooves 28 are formed in the concave side of the guide portions 27 and are of uniform generally rectangular cross-section. Each groove 28 is symmetrical about a plane containing the axis of the shank 22 of the ball.

Each groove 28 is associated with a springloaded arm in the form of a blade spring 29 of generally L-shape anchored by one limb 30 to the back of the carrier 14. The other limb 31 extends away from the carrier and its free end is urged into frictional engagement with its associated groove 28. The grooves 28 are slightly wider than the spring strip from which the spring blade 29 is made, to allow some freedom for the free end to twist about its areas of contact with the groove during adjustment of the mirror in some directions. Engagement of the blade springs 29 and grooves 28, however, prevents significant rotation of the reflective element 13 about an axis normal to its surface and through the centre of the ball joint. This keeps the periphery of the reflective element 13 out of contact with the rim 18 of the housing cowl The frictional engagement of the blade springs 29 and grooves 28 damps vibration of the reflective element 13 and helps to hold it in its adjusted position.

In the modification of Figures 5 and 6 the blade springs 29 are all included in a single three-armed member 32 formed of sheet spring material and secured to the carrier 14 by the central rivet 20 which secures the socket 19.

To prevent the three-armed member 32 from rotating, the rivet 20 may have a shank of square cross-section to engage complementary square holes in the carrier 14 and the member 32.

Alternatively the member 32 may have portions to engage suitable formations in the carrier 14, for example, the raised portions supporting the nipples 25.

In Figure 7 the blade springs 29 do not engage the grooves 28 directly, but have a round-headed rivet 33 secured to the free end of each blade spring 29 for this purpose. The grooves 28 are of part-circular cross-section complementary to the shape of the head. The domed shape of the rivet head allows greater freedom for angular movement between the blade spring 29 and the associated arm 26 which can occur during some movements of the reflective element 13 about the adjustable joint, for example movement about an axis 34 in Figure 7 parallel to the central part of the mounting plate 16 and lying in the plane of the paper.

In Figure 8 the blade springs 29 are replaced by hairpin springs 35 each anchored by the bend 36 to the carrier 14. At their free ends prongs 37 of the hairpin are parallel to one another and bent in a curve concentric with the ball joint 15. A cleat 38 secured at the centre to the limb 26 by a rivet 39 straddles both prongs which are embraced by the cleat 38 and the limb 26. During adjustment of the reflective element the prongs 37 slide with respect to the cleat 38 and the limb 26 so that in effect the deat 38 slides along the limbs 37. If some angular movement occurs between the spring 35 and the limb 26 about an axis normal to the surface of the limb engaged by the limbs, the cleat 38 can turn about the axis of rivet 39. Other angular movement between the spring 35 and the limb 26 can be accommodated by twisting of the spring 35.

WHAT WE CLAIM IS: 1. A rear view mirror for a motor vehicle having a housing adapted to be secured to the vehicle and a reflective element mounted within the housing by an adjustable joint which enables the reflective element to be adjusted in relation to the housing to alter the rear view wherein damping means comprises, angularly spaced around the adjustable joint, spring-loading arms anchored to the reflective element our the housing and each making slidable frictional engagement with an associated guide in unity with the housing or the reflective element respectively, the arrangement being such that the spring loaded arms and the guides are constrained to remain in interengagement and to relative arcuate movement about the adjustable joint in the direction of movement of the reflective element with respect to the housing which occurs during adjustment of the reflective element to alter the rear view.

2. A rear view mirror according to claim 1 wherein the guides have grooves in which the spring-loaded arms slide, the grooves being curved around the adjustable joint.

3. A rear view mirror according to claim 2 wherein the grooves are concentric with the adjustable joint.

4. A rear-view mirror according to claim 2 or claim 3 wherein the grooves are wider than the portions of the spring loaded arms which engage the grooves.

5. A rear view mirror according to any preceding claim wherein the spring-loaded arms are of spring strip, anchored at one end of each arm to the back of the reflective element.

6. A rear view mirror according to any preceding claim wherein the guides are formed as part of a mounting plate, secured to the housing and forming a support for the adjustable joint.

7. A rear-view mirror according to any preceding claim wherein the guide are limbs rigid with the housing and extending towards the back of the reflective element, the limbs being of part-spherical shape and concentric with the adjustable joint and having grooves on their inner, concave surfaces.

8. A rear-view mirror according to any of preceding claims 1 to 3 wherein the springloaded arms are furnished with round headed rivets which engage guide grooves of complementary, part-circular cross-section.

9. A rear-view mirror according to any of preceding claims 1 to 4 wherein each springloaded arm is formed by a hairpin shaped wire spring the prongs of which slidably engage the associated guide by which they are embraced, the spring-loaded arm being anchored at the bend of its hairpin shape and the prongs of the hairpin shape being curved and parallel to one another at least at the portions which slidably engage the associated guide.

10. A rear-view mirror according to claim 9 wherein a cleat secured to the arms straddles the portions of the prongs which slidably engage the associated guide.

11. A rear-view mirror substantially as described herein with reference to and as illustrated by Figures 1 to 4 of the accompanying drawings.

12. A rear-view mirror substantially as described herein with reference to and as illustrated by Figures 5 and 6 of the accompanying drawings.

13. A rear-view mirror substantially as described herein with reference to and as illustrated by Figure 7 of the accompanying drawings.

14. A rear-view mirror substantially as described herein with reference to and as illustrated by Figure 8 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. In Figure 8 the blade springs 29 are replaced by hairpin springs 35 each anchored by the bend 36 to the carrier 14. At their free ends prongs 37 of the hairpin are parallel to one another and bent in a curve concentric with the ball joint 15. A cleat 38 secured at the centre to the limb 26 by a rivet 39 straddles both prongs which are embraced by the cleat 38 and the limb 26. During adjustment of the reflective element the prongs 37 slide with respect to the cleat 38 and the limb 26 so that in effect the deat 38 slides along the limbs 37. If some angular movement occurs between the spring 35 and the limb 26 about an axis normal to the surface of the limb engaged by the limbs, the cleat 38 can turn about the axis of rivet 39. Other angular movement between the spring 35 and the limb 26 can be accommodated by twisting of the spring 35. WHAT WE CLAIM IS:

1. A rear view mirror for a motor vehicle having a housing adapted to be secured to the vehicle and a reflective element mounted within the housing by an adjustable joint which enables the reflective element to be adjusted in relation to the housing to alter the rear view wherein damping means comprises, angularly spaced around the adjustable joint, spring-loading arms anchored to the reflective element our the housing and each making slidable frictional engagement with an associated guide in unity with the housing or the reflective element respectively, the arrangement being such that the spring loaded arms and the guides are constrained to remain in interengagement and to relative arcuate movement about the adjustable joint in the direction of movement of the reflective element with respect to the housing which occurs during adjustment of the reflective element to alter the rear view.