Spigot type break-away mirror

Abstract: A spigot type breakaway mirror (10) for automobile exterior use includes both a supporting base (11) and a mirror subassembly (16), the base (11) having an upstanding spigot (12) which has a curved constraining surface (13), and the mirror subassembly (16) is provided with a locating surface (17) engageable over constraining surface (13) which constrains pivotal movement of the mirror subassembly to be about the spigot, but there are provided a cam pad (23) and recess surface (24) on the base and mirror subassembly respectively, and a spring (20) which cooperates between the base and mirror subassembly to retain the cam and recess surfaces in engagement, but the cam pad (23) and recess (24) surfaces cause the mirror subassembly (16) to cam outwardly away from the supporting base (11) if the mirror subassembly is caused to deflect upon striking an obstruction.

Description: This invention relates to a breakaway mirror for automobile exterior use comprising a base having a mounting portion adapted to abut against a vehicle body and a support platform projecting laterally from the mounting portion, a spigot upstanding on the support platform and having a curved constraining surface extending for at least some of its length, and a mirror subassembly having a locating surface engageable with the spigot constraining surface thereby constraining pivotal movement of the mirror subassembly to be about a pivotal axis of the spigot, cam and recess surfaces on the base and mirror subassembly located to one side of and spaced from said spigot, and spring means exerting a force between the spigot and the mirror subassembly in a direction at right angles to the pivot axis of the spigot to retain the cam and recess surfaces in engagement, but upon said pivotal movement occurring, relative movement of said cam and recess surfaces effects movement against said force exerted by the spring means, of the locating surface over the spigot and of the mirror subassembly outwardly away from the mounting portion of the base. A mirror of this type is disclosed in JP-A-59195449 in which said cam and recess surfaces provide the only radial abutment. WO-A-8900518 discloses a breakaway mirror for automobile exterior use of the type comprising a base having a mounting portion adapted to abut against a vehicle body and a support platform projecting laterally from the mounting portion, a spigot upstanding on the support platform and a mirror subassembly having a concave cylindrical locating surface which is a sliding fit on a convex surface of the spigot. No radial movement of the mirror subassembly relative to the spigot is possible. Consequently, it is difficult to provide sufficient clearance between the mounting base and the adjacent face of the mirror subassembly to avoid damage during breakaway, it of course being necessary for both appearance and avoidance of wind noise that the clearance between those two portions should be small. According to the invention, abutment pads co-act between the base and mirror subassembly and located to the opposite side of said spigot to the cam and recess surfaces, the abutment pads being retained in abutment by said spring means when said cam and recess surfaces are in engagement, but moving out of abutment upon said outward movement of the mirror subassembly. In this way a stable outboard 'in use' condition is provided for the mirror subassembly, while the clearance between the mirror subassembly and the base is increased upon the first stages of pivotal movement about the spigot so that the face of the mirror subassembly is clear of the base under normal breakaway conditions. An embodiment of the invention is described hereunder in some detail and is illustrated in the accompanying drawings in which: Fig. 1 is a plan view of two orthographic views of a spigot type breakaway mirror showing the base, the mirror subassembly and the breakaway mechanism therefor; Fig. 2 is a rear elevation of Fig. 1; and Fig. 3 is a fragmentary perspective view of the base showing the upstanding spigot. In this embodiment a spigot type breakaway mirror 10 is an assembly which comprises a base 11 (shown in perspective in Fig. 3), the base 11 being provided with fastening means (not shown) for fastening to the exterior of a vehicle. The base 11 has an upstanding spigot 12 which has a cylindrically curved surface 13 surrounding a pivotal axis 'A' extending for some of its length. The curved surface 13 functions more as a constraining surface than as a bearing surface, as described below. The spigot 12 is reinforced at its lower end by a boss 14 carried on a support platform 15 of the base 11. A mirror subassembly 16 has a locating surface 17 which defines an elongate aperture surrounding spigot 12 so that the mirror subassembly 16 is pivotable generally about the spigot axis 'A'. The mirror subassembly also has a housing 18 which houses a spring box 19 and at the other end against a pressure pad 21, the pressure pad 21 pressing against portion of the curved surface 13 of the spigot 12. This urges the housing 18, and thereby the mirror subassembly 16, in an inboard direction by the distance marked 'D' in Fig. 1. Base 11 is provided with a cam pad 23 projecting from a convexly curved surface of support platform 15. The cam pad 23 engages in a complementary recess 24 in a surface of the mirror subassembly 16, which is circularly curved about axis 'A'. It also lies in a plane Pr, which is a radial plane of the axis 'A' of spigot 12 (and vertical as drawn in Figs 1 and 2). In the curved surface of spigot 12 there is a central recess 25 and two peripheral recesses 26 and 27, recess 26 spaced from central recess 25 in a clockwise direction and recess 27 in a counter-clockwise direction. The drawings show the mirror subassembly 16 in its normal outboard position and in that position, the central recess 25 receives a projection 28 which extends radially inwardly from locating surface 17. Pivotal breakaway movement can only occur when the mirror subassembly 16 moves out of central recess 25 by the distance 'D', compressing spring 20 upon pivotal breakaway movement, so that the projection 28 can traverse the curved surface 13. This movement is provided by cam pad 23, but is limited by abutment of a central rib 29 after about 60° of movement, against one or other of ribs 30 upstanding from base platform 15. In either one of those positions, the projection 28 engages in a respective one of recesses 26 or 27, and retains the mirror "park" position until it is reset. The central recess 25 does not necessarily provide a cam action, but provides a space to receive the projection 28 when the mirror is in its outboard "in use" position. When cam pad 24 is in recess 23, two abutment pads 32 on the mirror subassembly 16 lie in face to face abutment with two abutment pads 33 on base 11. The abutment pads 32 and 33 are in a second horizontal plane P2, the cam pad 23 and recess 24 in a first horizontal plane P1, and the spring 20 in an intermediate horizontal plane Pi mid way between planes P1 and P2. Thus the pressure exerted by the spring provides a stable three point outboard condition for the mirror subassembly 16 when viewed in the front elevation of Fig 2. The abutment pads 32 and 33 are equally spaced on opposite sides of the radial plane Pr as viewed in Fig 1, so that the stable condition occurs also in plan. The mirror subassembly is thereby substantially free of vibration when in its outboard position. The inboard upper edge of the spigot 12 is provided with a pair of opposite retention lips 34, each having a lead in chamfer 35 and the pressure pad 21 is also provided with a chamfer at 36 which rises over the chamfer 35 upon assembly, and this greatly facilitates assembly since the spring box 19 can most conveniently be first assembled to the mirror subassembly 16 and the entire assembly then positioned over the spigot 12 by positioning substantially at right angles to its outboard in-use position, and subsequently rotating to that position, where it is retained by the lips 34. Once in position, the lips 34 on the upper end of spigot 12 will retain the assembly (see Fig. 1), but disassembly is easily effected by rotating the mirror subassembly 16 from its outboard position (past ribs 30), compressing spring 20 and then releasing the spring box from the spigot 12 by an axial movement. In place of the lips 34, a single lip may be provided on the radial Pr plane and assembly effected with the mirror subassembly 16 in its outboard position. Use of two lips 34 (as shown) is preferred because this reduces danger of dislodgement which can conceivably occur if only a single lip is used. Clearly the locations of the abutment pads and cam pad and recess can be reversed, cam pads and recesses lying in plane P1 and abutment pads in plane P2. If the distance between the plane P1 and the location 37 (where the upper surface of the mirror subassembly 16 meets the upper surface of the base 11) is smaller than illustrated, planes P1 and P2 will be closer to each other and the boss 14 will be shorter or non-existent.

Claims: A breakaway mirror for automobile exterior use comprising a base (11) having a mounting portion adapted to abut against a vehicle body and a support platform (15) projecting laterally from the mounting portion, a spigot (12) upstanding on the support platform (15) and having a curved constraining surface (13) extending for at least some of its length, and a mirror subassembly (16) having a locating surface (17) engageable with the spigot constraining surface (13) thereby constraining pivotal movement of the mirror subassembly (16) to be about a pivotal axis (A) of the spigot (12), cam and recess surfaces (23, 24) on the base (11) and mirror subassembly (16) located to one side of and spaced from said spigot (12), and spring means (19, 20) exerting a force between the spigot (12) and the mirror subassembly (16) in a direction at right angles to the pivot axis of the spigot to retain the cam and recess surfaces (23, 24) in engagement, but upon said pivotal movement occurring, relative movement of said cam and recess surfaces (23, 24) effects movement against said force exerted by the spring means (19, 20), of the locating surface (17) over the spigot (12) and of the mirror subassembly (16) outwardly away from the mounting portion of the base (11), characterised by abutment pads (33, 32) co-acting between the base (11) and mirror subassembly (16) and located to the opposite side of said spigot (12) to the cam and recess surfaces (23, 24), the abutment pads (33, 32) being retained in abutment by said spring means (19, 20) when said cam and recess surfaces (23, 24) are in engagement, but moving out of abutment upon said outward movement of the mirror subassembly (16). A mirror according to claim 1, wherein said cam surface is a surface of a cam pad (23) which extends in a radially outboard direction from the base (11), said recess surface (24) is a complementary surface of the mirror subassembly (16), and said abutment pads (33, 32) includes two pads circumferentially spaced from one another inboard of the spigot. A mirror according to claim 1 or 2, wherein said cam and recess surfaces (23, 24) lie in a first plane (P1) at right angles to said spigot axis (A), and said abutment pads (33, 32) lie in a second plane (P2) parallel to said first plane (P1), said spring means (19, 20) exerting said force between said spigot (12) and mirror subassembly (16) at a location between said first and second planes (P1, P2). A mirror according to claim 3, wherein said cam and recess surfaces (23, 24) lie in a radial plane (Pr) which is at right angles to the first plane (P1) and which contains said spigot axis (A), said spring means (19, 20) applying said force between said spigot (12) and mirror subassembly (16) in the radial plane (Pr), and said abutment pads comprising two abutment pads (33, 32) on opposite sides of the radial plane (Pr). A mirror according to claim 4, wherein said cam surface comprises a single cam pad (23) which extends radially outwardly from the base in said radial plane (Pr). A mirror according to any preceding claim, wherein said spring means (19, 20) comprise a spring box (19) carried by the mirror subassembly (16) and housing a spring (20) and pressure pad (21), said pressure pad (21) bearing against said spigot constraining surface (13) in an intermediate plane (Pi) between said first and second planes (P1, P2) releasably retaining a said cam surface (23) in engagement with a said recess surface (24). A mirror according to claim 5, wherein an upper end of said spigot (12) has at least one radially extending retaining lip (34) and a chamfer lead-in surface (35), said chamfer surface (35) facilitating assembly of the spring box (19) to said spigot (12), and said lip (34) retaining said locating surface (17) in engagement with said spigot constraining surface (13). A mirror according to any preceding claim, wherein the base (11) comprises an outwardly projecting platform (15) carrying the spigot (12), a cylindrical surface (13) circularly curved about an axis (A) of said spigot contains axially extending surfaces which define three circumferentially spaced recesses (25, 26, 27), each extending at least part way along the spigot (12), and the mirror subassembly comprises a radially inward projection (28) which selectively enters said recess surfaces (25, 26, 27).

Inventors: FRANCIS NEIL JAMES, GILBERT ROBERT WILLIAM, FRANCIS, NEIL JAMES, GILBERT, ROBERT WILLIAM
Applicants: BRITAX RAINSFORDS PTY LTD, BRITAX RAINSFORDS PTY. LIMITED
Application year: 1991
Main classification: B60R1
IPC codes: B60R1