Vehicle Mirror Assembly

This invention relates to mirror assemblies for vehicles, and more particularly, to an improved rearview mirror assembly for mounting within a vehicle. The assembly allows movement between a full light-reflectivity day position and a reduced light-reflectivity night position with a simplified, more reliable structure.

Rearview mirror assemblies allowing movement between day and night light-reflectivity positions have been used for many years. Governmental concern for strength, bending resistance, breakaway ability, and other safety requirements, as well as recent concern for weight and cost reduction in vehicles to provide energy savings, have dictated a reexamination of existing mirror assembly designs.

In the past, different day/night rearview mirror assemblies had been designed for different vehicles and the varying requirements of different countries in which automobiles or other vehicles are manufactured. In the United States, not only must the inside rearview mirror for a passenger car provide a predetermined field of view, but it must be mounted so that it is stably supported, is both horizontally and vertically adjustable, and can deflect, collapse or break away from its supported position without leaving sharp edges when subjected to a predetermined force in the forward direction within predetermined angular boundaries.

In the European Economic Community, motor vehicle regulations require that a rearview mirror assembly be able to withstand a static load test including the support of a 25 kilogram weight at one edge while any bracket support and the opposite edge are fixedly restrained for one minute. The assembly must pass the test without breaking or, if the assembly does break, without glass fragments being released. Alternately, the mirror may be made of safety glass.

Certain manufacturing difficulties have also been discovered with prior known assemblies. For instance, in the manufacture of certain rearview mirror assemblies it is necessary to heat and form a rectilinear lip on a molded case into a rounded edge covering the periphery of the mirror element after its insertion within a case. Difficulty has been experienced in consistently obtaining uniform mirror retaining lips in such assemblies. In addition, it was desired to more easily obtain positive control of the day/night pivoting action of the mirror assembly, especially in varying weather and climatic conditions.

With respect to assemblies which include a substantially rigid case with a pivot actuator including a flexible portion which provides resilience during pivoting, it was desired to obtain greater strength through the assembly area in which the pivot actuator was mounted.

Further, it is necessary that a mirror assembly meet minimum vibration standards so as to present a clear image when viewed by the driver of the vehicle, all while maintaining strength sufficient to meet the above-noted governmental regulations. A reduction in the complexity of prior assemblies was also desired to both decrease costs and simplify manufacturing requirements without sacrificing functional features.

The present invention was developed as a simplified, reliable, inside, day/night rearview mirror assembly for use in virtually all currently manufactured general use vehicles. The objective was to provide a mirror assembly useful in varying climatic conditions and which takes into account the governmental safety requirements for the major vehicular producing countries of the world. The present mirror assembly was thus designed and produced in recognition of the need for a simplified structure for retaining a mirror element within a case, the need to keep manufacturing rejection rates of the assemblies to a minimum, the need for simpler, more positive control of the day/night pivoting action while providing fewer overall parts, and the need to maintain strength, reduced weight, and resistance to vibration during use.

Accordingly, the present invention provides a simplified, reliable, inside day/night rearview mirror assembly for vehicles which is adapted to provide easier assembly and smaller manufacturing rejection rates, simplified retention of the mirror element within the case, proper resistance to vibration during use, fewer overall parts, more positive control of day/night positioning, and proper strength with reduced weight. In addition, the present invention provides the capability of use with a one-piece mirror support bracket as disclosed in copending, commonly assigned United States patent application Ser. No. 276,839, filed on even date herewith, entitled "REARVIEW MIRROR SUPPORT BRACKET," and invented by Denis Wood, John F. Thomas, Jr., Barry Dipper, Philip D. Stegenga, John H. Veldkamp, William L. Katsma, Robert L. Norton and Denis Rick. Together with such bracket, the present rearview mirror assembly takes into account the governmental vehicle safetly regulations in both the United States and the European Economic Community and provides easier, less costly manufacturing while maintaining the proper strength and vibration requirements, all with a minimal overall weight. The combination of the present rearview mirror assembly and the mirror support bracket is disclosed and claimed in copending, commonly assigned United States patent application Ser. No. 276,838, filed on even date herewith, entitled "VEHICLE MIRROR AND SUPPORT ASSEMBLY, and invented by Denis Wood, John F. Thomas, Jr., Barry Dipper, Philip D. Stegenga, John H. Veldkamp, William L. Katsma, Robert L. Norton and Denis Rick.

In one aspect, the present invention provides a day/night rearview mirror assembly for vehicles including a mirror case formed in one piece from resinous material and having flexible, resilient portions, and a rigid actuator means for moving the case between day and night positions. The case has a back, a continuous peripheral side wall adapted to outline the peripheral edge of a mirror element, retaining means for returning the mirror element in the case, and support means for supporting the actuator means within the case. The actuator means includes mounting means for mounting a bracket for securing the assembly on a support and pivot means for pivoting the actuator and case between the said positions. The case biases the actuator toward one or the other of the said positions such that a predetermined force is required to pivot the actuator and case with the pivot means.

In other aspects of the invention, the molded, mirror case includes a preformed lip on the continuous peripheral side wall which retains and allows snap-in insertion of the mirror element within the case. The pivot actuator is a substantially rigid toggle member. The case includes portions which are sufficiently flexible and resilient to bias the toggle member toward one or the other of the toggle member positions. The lip extends inwardly a distance sufficient such that, when a mirror element is received with the case, and the toggle member is pivoted with the pivot means, the lip will continue to cover the edge of the mirror element and a predetermined portion of the mirror element spaced inwardly from the edge thereof regardless of the flexing action of the case and the lip during pivoting.

In yet other aspects of the invention, the back of the case curves outwardly to an area of maximum overall case depth to facilitate flexing of the case during pivoting of the pivot means. Multi-faceted pivot limiting stop tabs are provided on the pivot actuator for positive control of the pivotal case movement between day and night positions and to allow easier insertion of the actuator within the case. In addition, the mounting means on the pivot actuator may be either a socket for receiving a ball member from a support bracket or an outwardly extending ball member to be secured in a suitable support bracket.

The snap-in retention of the mirror element within the case provides simplified assembly. Even during case flexure when the pivot actuator is moved between its positions, the retention lip provides sufficient coverage of the peripheral edge of the mirror element to hide minor chips, scratches or edge deviations so that fewer mirror assemblies need be rejected after manufacture. In addition, the multi-faceted stop tabs on the pivot actuator allow easier insertion of the actuator within the case than with prior known actuators and provide more positive control of day/night pivoting after assembly. The present assembly incorporates fewer overall parts while maintaining strength, vibration resistance and minimal weight. In addition, the assembly is fully compatible with a support bracket such as that shown in copending application Ser. No. 276,838 to allow proper use and operation in a wide range of vehicles as well as proper safety breakaway and adjustability features when so combined.

These and other objects, advantages, purposes and features of the invention will become more apparent from a study of the following description taken in conjunction with the drawings.

FIG. 1 is a front perspective view of the rearview mirror assembly of the present invention together with a suitable, breakaway-type, mirror mounting bracket;

FIG. 2 is a rear view of the rearview mirror assembly of the present invention together with the mirror mounting bracket shown in FIG. 1;

FIG. 3 is a front plan view of the molded mirror case of the present invention;

FIG. 4 is a top sectional view of the mirror case of FIG. 3 illustrating a glass mirror element mounted therein and taken along plane IV--IV of FIG. 3;

FIG. 5 is a side sectional view taken along plane V--V of FIG. 4;

FIG. 6 is a side sectional view of the mirror case and mirror element together with the pivot actuator mounted therein similar to FIG. 5;

FIG. 7 is a rear view of a first embodiment of the pivot actuator of the present invention;

FIG. 8 is a front view of the pivot actuator shown in FIG. 7;

FIG. 9 is a side sectional view of the pivot actuator taken along plane IX--IX of FIG. 8;

FIG. 10 is sectional view of the mirror case showing the mirror element as supported at the end of the case taken along plane X--X of FIG. 12;

FIG. 11 is a side sectional view of the case during insertion of the pivot actuator of FIGS. 7-9 into the case;

FIG. 12 is a front plan view of the case with the pivot actuator of FIGS. 7-9 mounted therein;

FIG. 13 is a front view of a second embodiment of the pivot actuator of the present invention;

FIG. 14 is a rear view of the pivot actuator as shown in FIG. 13;

FIG. 15 is a side view of the pivot actuator shown in FIGS. 13 and 14;

FIG. 16 is a side sectional view of the pivot actuator taken along plane XVI--XVI of FIG. 14; and

FIG. 17 is a side sectional view of the actuator taken along plane XVII--XVII of FIG. 13.

Referring now to the drawings in greater detail, FIGS. 1-6 illustrate a first embodiment of the inside rearview mirror assembly 10 including a molded, resinous mirror case 12 receiving a mirror element 14 and a rigid pivot actuator or toggle member 50 or 50'. Actuator 50 or 50' is pivotally mounted in the case and preferably molded from resinous material as will be described more fully hereinafter. Mirror element 14 is a prism of transparent glass, plexiglass, plastic or other transparent, rigid material having a layer of reflective material 16 (FIG. 5) placed on its rear surface. Preferably, element 14 is a glass prism having a taper of 3.degree. 35'.+-.0.degree. 10' and a maximum thickness of 0.218.+-.0.015 inches. The overall element is 9.27.+-.0.015 inches by 2.265.+-.0.015 inches with rounded corners, slightly curved edges, and a frosted non-glare edge all around. Such reflective layer may be coated with a protective primer paint layer followed by a flexible resilient polyvinyl chloride plastisol layer 18 or a covering of tape for safety reasons to prevent scattering of glass fragments should the mirror be broken.

In the preferred embodiment, layer 18 has a thickness of approximately 0.015 to 0.045 inches which thickness tapers and becomes less adjacent the edges of the mirror element 14 (see FIGS. 5 and 6). The reflective layer 16 is normally covered with a protective layer of primer paint over which the plastisol layer 18 is applied. The primer paint is preferably a heat sensitive adhesive and includes a pigment for hiding the reflective layer on the mirror. Acceptable products include Daubond DC-8660 by Daubert Chemical Co. of Oakbrook, Ill. or product No. A 1103 B, by B. F. Goodrich Chemical Company, of Cleveland, Ohio. Both have adhesive bonding qualities when heated.

After application of these various layers, the mirror element and layers are cured by heating to a temperature of approximately 175.degree.-200.degree. F. At this approximate temperature, the PVC plastisol 18 is chemically converted to polyvinyl chloride. Sufficient plastisizer is originally included in the plastisol to leave the cured layer 18 inherently resilient, flexible and impressionable at all temperatures to which vehicles including such mirrors are normally subjected, namely, a range of -40.degree. F. to 190.degree. F.

Although application of the PVC layer 18 is preferably done in plastisol form, the PVC in non-plastisol form may be injection molded onto the back of the mirror. When PVC is injection molded on the mirror back, it has been found that an additional layer of bonding agent or adhesive beneath the plastisol layer, which securely bonds the plastisol layer to the mirror element, is preferred. Such suitable heat sensitive adhesive is product No. J 1199-B, produced by Armstrong Cork Company, of Cincinnati, Ohio. Other materials having the above characteristics of resiliency and flexibility over a wide temperature range, which may also be used for layer 18, include polyvinyl acetate, polyurethane and silicone sealants.

As shown in FIGS. 5 and 6, the planar front surface and planar rear surface of mirror element 14 are not parallel thereby defining the prism and enabling adjustment of the mirror assembly for day and night use to reduce the overall intensity of the light reflected from the mirror. Thus, when the assembly is pivoted (FIG. 6) such that the case positions the mirror element with incident light reflected off the coated rear surface 16, substantially all, approximately 88 percent of the light hitting that surface will be reflected. However, when the case is pivoted such that light is reflected off the front, uncoated surface, only approximately 4 percent of the incident light will be reflected. Glare in the eyes of the driver viewing the mirror is thereby reduced.

As noted above, the rearview mirror assembly 10 is designed to be used with a support bracket 15 of the type disclosed in either copending application Ser. Nos. 276,839 or 276,838. Bracket 15 enables the mounting and adjustment of assembly 10 on a support which is typically secured on a windshield of a vehicle to provide proper adjustment for all sizes of drivers for such a vehicle. Bracket 15, which forms no part of the present invention, is also described and claimed in combination with the present rearview mirror assembly in application Ser. No. 276,838 noted above.

As is best seen in FIGS. 3-6, molded mirror case 12 includes a contoured, curved back 20 and a continuous peripheral side wall 22 which extends around the entirety of the case outlining the periphery of mirror element 14 when received therein. Side wall 22 defines top 22a, bottom 22b, and ends 22c and 22d. As shown in FIGS. 5 and 6, the thickness of the case back 20 is substantially uniform and preferably 2.5 mm while peripheral side wall 22 tapers outwardly to an increased thickness, preferably 3.0 mm, toward the front of the case where it merges with a continuous, inwardly extending mirror element retaining lip 24. Lip 24 extends around the entirety of side walls 22 and has a curved outer shape ending at inner edge 26 and an inclined under surface 28 adapted to face the mirror element 14. Inclined surface 28 prevents the lip from catching on the corner of the glass when the case flexes. The curved outer surface of the lip 24 cooperates with the bevel 19 on the rear surface of mirror element 14 when the mirror element is snapped into the case 12 by camming the lip and peripheral side wall combination outwardly in the manner shown in FIG. 10. Lip 24 extends inwardly over the entire peripheral edge of the mirror element a predetermined distance, 2.5 mm in the preferred embodiment, and is calculated to mask any edge defects in the glass or other mirror element and also to retain the mirror element in place even when the case flexes during pivoting of the day/night pivot actuator as set forth below.

As shown in FIGS. 2 and 5, the case back curves outwardly to an area of maximum thickness approximately at the central portion of the case as defined by a contour line 30 which extends from points 32, 33 adjacent the upper corners at either end of the case downwardly in a gentle curve toward the middle of the case intermediate upper and lower corner apertures 34 and 36 but immediately adjacent the bottom portion of the uppermost aperture 34. Contour line 30 not only defines an increased depth for the overall case, but also facilitates flexure of side walls 22 when the pivot actuator is pivoted within the case and/or the mirror element 14 is snapped in place during assembly of the mirror assembly. Along with ribs 50, 52, the contour of the case also increases longitudinal bending resistance or stiffness helping to meet governmental regulations. This contour provides a somewhat bulbous shape to the mirror assembly as shown in FIGS. 4-6, 10 and 11.

As shown in FIGS. 3 and 4, mirror case 12 also includes pairs of aligned, parallel, upstanding mirror supports 38, 40 on the interior of opposite ends 22c, 22d of the case. As shown in FIG. 5, these upstanding supports extend different distances to support the varying thickness of the prismatic mirror element 14 when retained in case 12 beneath inclined surface 28 of lip 24. When snapped in place, lip 24 tightly retains the mirror element against only supports 38, 40 to prevent any vibration or movement of the mirror element within the case. The mirror element is not supported by any other portions of the case.

As is best seen in FIGS. 3-6, the central, interior portion of case 12 includes a support area for pivot actuator or toggle member 60. The support area includes rectilinear, parallel, support walls 42, 44 each of which includes a free, rectilinear top edge which is spaced behind layer 18 of mirror element 14 when received in case 12, and is generally parallel to coated rear surface 16 as shown in FIG. 5. Each of the support walls 42, 44 includes a cutout or opening 46, 48, respectively, having nonparallel top and bottom edge surfaces which converge toward top wall 22a. Openings 46, 48 are bounded by an area of increased thickness 47, 49 on the interior surface of each wall 42, 44, respectively, to strengthen the wall around the opening. Openings 46, 48 are designed to receive the pivot limiting stop tabs from pivot actuator 50 as described hereinafter. In order to strengthen the support area and case in its central section, a pair of upstanding, molded support ribs 50, 52 extend generally rectilinearly and parallel to one another but are spaced slightly apart across the area between walls 42, 44. Rib 50 is generally aligned with the contour line 30 defining the area of maximum depth of the case in the area between walls 42, 44 immediately under aperture 34.

Molded integrally and extending inwardly from the inside surfaces of support walls 42, 44 are aligned pairs of pivot supports 54a, 54b and 56a, 56b which support the top and bottom pivot axles of the pivot actuator or toggle member 60 respectively. Pivot supports 54a, 54b each include an axle support wall 55 (FIG. 5) having an inside surface contour including cylindrical surfaces of two different radii joined by a planar surface 53 designed to match the exterior contour of the upper pivot axles stubs on the pivot actuator 60. Axle support walls 55 are, in turn, supported by ribs 57 extending between the upper sides of the walls 55 and the upper side wall 22a of the case.

Similarly, lower pivot supports 56a, 56b include axle support walls 58 supported by additional rib 59 extending between the axle support and bottom side wall portion 22b. Axle support 58 includes an inner, partially cylindrical uniform radius support opening generally toward an opposed, aligned one of the upper pivot supports 54a, 54b. As will be more fully described below, pivot actuator 60 is designed to be snapped in place between the sets of pivot supports 54, 56 and between support walls 42, 44 after molding of the case and prior to insertion of the mirror element 14. Referring now to FIGS. 7-9, a first embodiment 60 of the pivot actuator or toggle member is shown. Actuator 60 includes a pair of spaced pivot axles 62, 64 designed to be received in supports 54a and b, 56a and b, respectively, a rigid body 66 including a series of strengthening ribs or braces 67, a pair of opposed pivot limiting stop tabs 68a, 68b on opposite sides of the body 66, a mounting socket 70 extending outwardly from the upper pivot axle 62, and a pivot member including lower pivot axle 64 adapted to enable pivotal movement of the actuator between at least two positions, i.e., the forward or day and the rearward or night position when mounted within the case.

Upper pivot axle 62 includes a pair of stub axles 62a, 62b extending parallel to one another and in opposite directions from the upper side edges of the body 66 of actuator 60. Stub axles 62a, 62b have cylindrical surfaces of different radii joined by a planar surface in the same fashion as the inside surfaces of axle supports 55 on pivot supports 54a and b in case 12. The larger cylindrical surface extends approximately one third to one quarter of the way around the pivot axle, the increased radii providing the stub axle with greater strength. However, the smaller cylindrical radius portion enables the actuator to be more easily fitted in pivot supports 54a and b. Rigid body portion 66 includes a pair of diverging legs which are channel-shaped in section extending between the pivot axles. These legs provide a general V-shape for the body section as best seen in FIG. 8. The channel-shape provides weight reduction while the cross braces, such as those shown at 67 in FIGS. 7 and 9, both within the side wall of each diverging leg and between the legs themselves, provide significantly increased strength and rigidity for the body portion without adding significant weight. The front surfaces 65 of the diverging legs 66 lie in a common plane slightly offset from the center lines of the pivot axles 62, 64.

At the lower edges of the legs of the actuator pivot axle 64 is joined by a flexible, integrally molded living hinge 72. Projecting downwardly from the bottom of pivot axle 64 is a pivot or finger tab 74 having integral ribs molded thereon for ease in gripping. Living hinge 72, tab 74 and pivot axle 64 together form an over-center hinge assembly in combination with the rigid body 66 which operates as more fully described hereinafter.

Pivot limiting stop tabs 68a, 68b, which extend from the opposite side surfaces of the rigid body 66, each include multiple facets or planar surfaces intersecting one another as shown in FIGS. 6-8 and 11. The front surfaces 76 of stop tabs 68 are designed to engage the upper edge of cutout apertures 46, 48 in support walls 42, 44 to limit the pivotal movement of the actuator to its day position (FIG. 11). On the opposite side of each stop member, facets 78 provide a stop surface limiting pivotal movement of the actuator 60 to its night position (FIG. 11). Inclined facets 80 provide camming surfaces helping insertion of the actuator between the support walls 42, 44 when it is assembled within the case.

As shown in FIG. 9, the molded socket 70 has a central axis "A" which extends outwardly at an obtuse angle with respect to the plane of front surfaces 65 of legs 66. Socket 70 has a slightly elongated or egg shape and is not perfectly spherical such that a ball member from a support bracket does not touch socket wall 71 at all places (FIG. 9). Socket wall 71 has a substantially uniform thickness adapted to provide sufficient support for a ball member but allow insertion of such a ball without fracturing. Wall 71 is strengthened by braces 69. Inclined, conical lead-in surface 82 facilitates snap-in insertion of a spherical ball member from a mounting bracket or the like to be received in the socket as described in copending application Serial No. 276,838 incorporated above. Aperture 84 results from removal of a mold pin during manufacture. When received in case 12, socket 70 is adapted to project through upper corner aperture 34, while pivot tab 74 extends through lower corner aperture 36 as shown in FIG. 6.

Alternately, as shown in FIGS. 13-17, a revised form 60' of the pivot actuator is shown wherein like numerals indicate like parts to those shown in embodiment 60. Actuator 60' includes an outwardly extending ball member 86 in place of socket 70. Ball member 86 is molded into support area 85 at the apex of the diverging legs which form body 66 such that it extends outwardly from upper pivot axle 62. Ball member 86 preferably includes a zinc die cast or other metallic, spherical ball 87, neck 88, and a base including parallel circular members 89 and 90 about which is molded support area 85. Ball portion 87 is designed for receipt in a spherical cup or other receiving member in a mounting bracket extending between the pivot actuator and a support such as a metallic button on the windshield of a vehicle. The central axis of ball member 86 extends at the same angle as does the axis "A" of socket 70 with respect to the planar surfaces of diverging legs 65, and thus extends through upper corner aperture 34 when received in case 12. Accordingly, depending on whether actuator 60 or 60' is chosen, the assembled rearview mirror may be used with varying support brackets while continuing to provide complete adjustability for viewing by varying sizes of drivers.

Preferably, both case 12 and actuators 60 or 60' are molded in one piece from resinous, thermoplastic material such as a homopolymer or copolymer of polypropylene. Such material has been found to have the necessary strength and rigidity for forming the actuators 60, 60'. Yet in the configuration of the case 12, these materials have the necessary flexibility and resiliency to function as intended. Preferably, actuators 60, 60' are molded from a homopolymer of polypropylene such as Hercules 6523 made by Hercules, Inc. of Wilmington, Del. or equivalent. Hercules 6523 has the following properties:

Flexural modulus (ASTM D790B): 250,000 psi;

Hardness (ASTM D 785A): 99 (Rockwell R scale);

Deflection temperature (ASTM D648): 212.degree. F. (66 psi;

Notched Izod impact strength (ASTM D 256A): 0.8 ft.-lbs./in (at 73.degree. F.)

A preferred polypropylene copolymer for case 12 is Hercules 7523 or equivalent. Hercules 7523 has the following properties:

Flexural modulus (ASTM D790B): 185,000 psi;

Hardness (ASTM D785A): 80 (Rockwell R scale);

Deflection temperature (ASTM D648): 81.degree. F. (at 66 psi);

Notched Izod impact strength (ASTM D256A): 2.5 ft.-lbs./in (at 73.degree. F.)

It has been found that the actuator, mirror element and case can be best assembled within a predetermined time period after completion of the molding of the case so as to utilize the case while its temperature remains above a predetermined level at which the case has a greater flexibility and lesser resiliency which facilitates assembly. Initially, the cylindrical surfaces of pivot supports 56a, 56b are coated with a suitable lubricant such as a grease sold as Lubriplate 930-2 by Firske Bros. Refinery, Newark, N.J. The grease provides consistency in the pivot torque for movement between day and night positions. One of the actuators 60 or 60' is then inserted as shown in FIG. 11 such that socket 70 or ball member 86 projects through aperture 34 while pivot tab 74 and pivot axle 64 are rotated such that pivot tab 74 extends through lower corner aperture 36. Inclined surfaces 80 of pivot limiting stop tabs 68a, 68b are brought into engagement with the rectilinear upper edge surfaces of support walls 42, 44 while pivot stub axles 62a, 62b are being pushed into and seated within the cylindrical surfaces of pivot supports 54a, 54b all as shown in FIG. 11. Thereafter, sufficient force is applied in the direction of the arrow in FIG. 11 to force actuator 60 downwardly between support walls 42, 44 such that inclined camming surfaces 80 on the pivot limiting stop tabs 68a, 68b force walls 42, 44 to bulge outwardly allowing the pivot stop tabs to pass between them and into apertures 46, 48. Since case 12 is at an elevated temperature, the support walls 42, 44 have a greater degree of flexibility and lesser resiliency than after a longer period of cooling, thereby facilitating the above insertion process. When stop tabs 68a, 68b are received within apertures 46, 48, the lower pivot axle 64 is seated in pivot supports 56a, 56b as shown in FIG. 6.

Inasmuch as actuators 60, 60' include rigid bodies 66 which maintain a predetermined spacing between axles 62, 64, an interference fit is provided between the pivot axles of the actuator and the pivot supports of case 12 by making the distance Y (FIG. 7) between the outside surfaces of the pivot axles slightly greater than the distance X (FIG. 5), the greatest distance between the cylindrical surfaces of the pivot supports. Accordingly, when actuator 60, 60' is snapped into place as described above, this interference, which is 0.030 inches in the preferred embodiment, flexes the side walls 22 and a portion of the case back 20 outwardly in the manner shown in phantom in FIG. 11. This provides a prestressed condition which causes the lower axle 64 to bow slightly intermediate the supports 56a, 56b as shown in FIG. 12. After the assembled case and actuator have cooled sufficiently to ambient, normal temperatures, the resiliency of the resinous, thermoplastic material at those temperatures constantly biases the over-center pivot assembly on the actuator into one or the other of its two positions as limited by the stop tabs within apertures 46, 48. Accordingly, the case itself acts as a spring member urging the pivot actuator to either its day or night position and maintaining the actuator in that position. The preferred flip angle of movement between the day and night positions of actuator 60 or 60' is 5.degree. 29'.+-.0.degree. 30' using the pivot limiting stop tabs 68 and apertures 46, 48.

Before the case has cooled to ambient temperatures, however, the increased flexibility and reduced resiliency of the continuous side walls 22 of the case 12 facilitates insertion of the prism mirror element 14 by snapping it into position as shown in FIG. 10. Such insertion is facilitated by bevel 19 on the rear edge corner of the mirror element camming against the rounded surface of lip 24 adjacent edge 26 such that the top, bottom and end surfaces of the case are flexed outwardly (FIG. 10). This allows inward movement of the mirror element to a position under lip 24 and against supports 38, 40. Thereafter, the continuous lip flexes inwardly from its expanded position to retain the edge of the mirror element under the lip 24.

It has been found that, with the preferred materials noted above, the insertion of both the actuator 60 or 60' and the mirror element 14 is best achieved within one to three minutes after removal of the case from the mold so as to take advantage of the greater flexibility and lesser resiliency of the case at an elevated temperature. Thereafter, the case cools to retain mirror element and actuators in position and to provide the prestressed, biasing force described above.

During use of the mirror assembly described above, it will be noted that, as shown in FIG. 6, pivotal movement of the tab 74 between its day and night position increases the distance between axles 62, 64 when tab 74 and hinges 72 are generally parallel to the front surface 65 of rigid body 66 and until the actuator is over-center toward one position or the other. Such increased distance flexes the continuous side walls and a portion of case back 20 outwardly (FIGS. 10 and 11) against the natural resiliency of the case providing a predetermined force level which must be overcome by a pivoting torque or force applied against pivot tab 74. Once such force is applied and the pivot tab is moved over center, the biasing force of the case will snap the actuator into its opposite position as limited by the surfaces on pivot limiting stop tabs 68 within apertures 46, 48. Depending on the magnitude of the interference fit between actuator 60 or 60' and supports 54, 56, and the stiffness and resiliency of the case and actuator, which can be varied by the amount of case set or cooling allowed before actuator insertion, such pivoting force will preferably be between about one and three pounds. This is sufficient to allow movement between day and night positions while providing good feel and keeping the actuator in one of its positions after movement in accord with desired design objectives. In addition, pivot limiting stop tabs 68 provide positive assurance against premature removal of the pivot actuator or toggle assembly from pivot supports 54, 56 such as could occur by a sharp force applied against the mirror assembly tending to move the pivot actuator forwardly towards the mirror element when mounted in a vehicle. The closed apertures 46, 48 which limit movement of the pivot stop tabs 68 effectively prevent such removal of the actuator after assembly.

Accordingly, the present invention provides a simplified, highly reliable rearview mirror assembly which provides requisite strength with lightness, fewer overall parts compared to prior known mirror assemblies, simplified assembly procedures coupled with consequent reduction in rejection rates for the assemblies, and more positive control of the day/night pivoting action. In addition, the assembly is adapted to meet safety requirements for major vehicle producing countries.

While several forms of the invention have been shown and described, other forms will now be apparent to those skilled in the art. Therefore, it will be understood that the embodiments shown in the drawings and described above are merely for illustrative purposes, and are not intended to limit the scope of the invention which is defined by the claims which follow.