Vibration stabilized rearview mirror for vehicles

A vibration-stabilized rearview mirror assembly for vehicles includes a reflective mirror element pivotally mounted in a mirror housing with at least one vibration stabilizer slidably mounted on and biased outwardly beyond the perimeter edge of the mirror element to engage the inside of the housing and to dampen and reduce vibration of the mirror element. Preferably, two stabilizers are slidably mounted parallel to the mirror element at spaced locations and are engaged by a single spring which equalizes the spring force on both stabilizers. Stop surfaces limit extension of the stabilizers.

FIELD OF THE INVENTION 
This invention relates to rearview mirrors for vehicles and, more 
particularly, to a vehicular rearview mirror assembly, and especially an 
exterior rearview mirror assembly, including vibration 
dampeners/stabilizers which reduce the vibration of an adjustable mirror 
element within its housing caused by road shocks, vehicle operation and/or 
air turbulence. 
BACKGROUND OF THE INVENTION 
Rearview mirror assemblies used in motor vehicles, and especially exterior 
rearview mirror assemblies secured to the sides of a vehicle, typically 
include manual or electrical adjustment mechanisms allowing movement of 
the reflective mirror element to various positions suitable for viewing 
traffic and other conditions to the side and rear of the vehicle. As a 
consequence of such adjustable mounting, various sources of vibration 
affect the visibility of images reflected by the mirror element causing 
both annoyance and a safety hazard. Vibration results from road surface 
discontinuities over which the vehicle is driven, such as textured 
surfaces, bumps, potholes, uneven seams and/or rumble strips, as well as 
from various vehicle components including the engine, gear box, drive 
shaft and the like. In addition, vibration also results from air 
turbulence created by the air flow over the exterior mirror assembly in 
the vehicle slip stream, or from off axis wind striking the reflective 
mirror element. 
Until recently, the problem of vibration in exterior rearview mirror 
assemblies has not received significant attention, particularly in North 
America. However, as vehicle specifications have evolved, vehicle 
suspensions have become stiffer and minimum driving speeds have moved 
upwardly resulting in greater vibration affecting the rearview mirror as 
well as increased driver awareness of vibration affecting his or her 
vision. 
Many solutions to exterior mirror assembly vibration have been proposed. 
These include the use of significantly stiffer polymer resins to support 
the glass and/or actuator assemblies in such mirrors. In addition, 
radially mounted, anti-vibration members on the rear surface of the 
reflective element subassembly for engagement with the surrounding mirror 
have also been used. To date, such anti-vibration members have constituted 
one or more spring-loaded, contact members which are usually mounted on 
the axis of rotation of the reflective element or radially around its 
center of rotation. In one structure currently in use, a contact member is 
pivotally mounted to the edge of a mirror support behind the reflective 
mirror element and urged outwardly by a coil spring into engagement with a 
curved surface on the inside of the mirror housing. The curved contact 
surface follows a radius of the center of rotation of the mirror element. 
In other currently known structures, outwardly extending, metallic spring 
members are positioned adjacent the edge of the rear surface of the mirror 
element on a support member and are sufficiently resilient to be urged 
outwardly into contact with the inside surface of the mirror housing. 
Again, the inside surface of the housing in such structures is formed 
along a radius of the center of rotation of the mirror element such that 
the distance between the contact member and the engaged surface remains 
constant during all pivotal movement of the mirror element. 
In each of the currently known rearview mirrors incorporating 
anti-vibration structures, the individual contact points must have an 
essentially spherical mating surface to ensure constant force and 
continuous engagement with the mirror housing. However, this significantly 
limits the designs available for such mirror assemblies. For example, the 
mirror housing must be formed in a specific spherical shape or include an 
internal component, such as a bracket, which includes a spherical surface, 
for contact with the contact members. Further, each contact member must be 
formed from a spring material, or requires its own independent spring to 
insure substantially uniform loading. As such, the radially positioned 
surface requirement limits design freedom and increases component costs 
for the mirror housing and/or bracket. In addition, multiple components 
are required and the complexity of the assemblies is increased due to such 
requirements. Further, the cost and expense for manufacturing such 
assemblies is significantly increased because of increased tooling 
complexity. 
The present invention provides a lower cost, simplified vibration 
stabilized rearview mirror assembly for vehicles, and especially exterior 
mirrors which overcomes the above problems while providing greater design 
flexibility, requiring fewer components, and being less costly and complex 
to manufacture. 
SUMMARY OF THE INVENTION 
Accordingly, the present invention provides a vibration stabilized rearview 
mirror assembly for vehicles, and especially exterior rearview mirror 
assemblies, in which one or more vibration dampeners or stabilizers are 
mounted on the pivotally adjustable reflective mirror subassembly such 
that they are slidably extended and retracted by a spring member but 
without requiring the provision of a surface on the surrounding mirror 
housing which is at a fixed radial distance from the center of the 
rotation of the mirror element. Hence, rearview mirror housings of various 
designs which need not always include a spherical interior surface may be 
used, thereby providing greater design flexibility, lower costs and 
improved visibility in the mirror. 
In one form, the invention is a vibration stabilized rearview mirror 
assembly for vehicles including a mirror housing having an inside surface 
defining an interior space, a reflective mirror element having a perimeter 
edge and adjustably mounted for pivotal movement within the housing 
interior space and, a vibration stabilizer mounted for sliding movement on 
the mirror element, extending beyond the perimeter edge of the mirror 
element and engaging a first portion of the inside surface of the housing. 
A spring engages and biases the stabilizer outwardly of the mirror element 
perimeter edge such that the stabilizer continuously engages the inside 
housing surface to reduce vibration of the mirror element. The stabilizer 
is extended by and retracts against the spring to adjust for varying 
distances between the perimeter edge of the mirror element and the inside 
housing surface when the position of the mirror element within the housing 
is adjusted. 
In preferred aspects of the invention, the mirror assembly also includes a 
second vibration stabilizer mounted for sliding movement on the mirror 
element and also extending beyond the perimeter edge thereof at a position 
spaced from the first stabilizer. The second stabilizer engages a second 
portion of the inside housing surface while the spring simultaneously 
engages both the first and second stabilizers and simultaneously biases 
both the stabilizers into engagement with their respective inside housing 
surface portions. Thus, the need for separate springs for each stabilizer 
is eliminated. 
In other aspects, each stabilizer is preferably supported by a slide mount 
for sliding movement in a predetermined direction and generally parallel 
to the rear surface of the mirror element. Preferably, the stabilizers 
extend at right angles to one another, such as across the top or bottom 
edge of the mirror element and across one of the end edges. 
In addition, the stabilizers may be mounted on a support member or holder 
for the reflective mirror element and may be mounted either on the rear 
surface of the support member or the front surface intermediate the 
reflective mirror element and the support member. In either case, the 
stabilizers preferably include a shoulder which engages a stop surface 
which limits extension of the stabilizer such that each stabilizer 
constantly engages the spring and remains under load. Use of the single 
spring member provides generally equivalent loading of the stabilizers but 
without the need to match and support multiple spring members in the 
assembly. Preferably, an elongated spring extends around a spring support 
and has a pair of outwardly extending ends of generally equivalent length, 
one of the spring ends engaging the first stabilizer and the other of the 
spring ends engaging the second stabilizer. If desired, a second pair of 
stabilizers could also be included for additional vibration reduction. 
Such stabilizers would preferably extend beyond the perimeter edge of the 
mirror element at positions opposed to the positions of the first set of 
stabilizers. 
As will be understood from the various embodiments of the invention, the 
present vibration stabilized rearview mirror assembly for vehicles 
provides greater flexibility in design of the mirror housing since 
spherical surfaces which are positioned at a constant radial distance from 
the center of rotation of the mirror element in the housing are no longer 
required in order to provide proper vibration dampening or stabilization. 
The slidable mounting of the vibration stabilizers in the present 
invention enables varying distances between the edge of the adjustable 
mirror element and the inside mirror housing surface to be easily 
accommodated while contact is maintained. In addition, the complexity of 
the present invention is reduced as compared to prior known vibration 
stabilized rearview mirror assemblies which require separate springs for 
each contact member or require formation of the contact members from 
spring material. Rather, in the present invention, a single spring 
preferably operates a pair of vibration stabilizers while maintaining 
substantially equivalent loading on each regardless of the distance 
between the edge of the pivotal mirror element and the inside housing 
surface. As a consequence, mirror housings may be designed with a wider 
range of configurations while costs are reduced due to more simplified 
construction. 
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.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawings in greater detail, FIG. 1 illustrates a first 
embodiment 10 of a vibration stabilized exterior rearview mirror assembly 
for motor vehicles incorporating the present invention. Assembly 10 
includes an aerodynamically shaped mirror housing 12 connected to a 
support structure conventionally known as a "sail" 14 by a hollow, 
connecting neck 16. Mirror housing 12, along with support 14 and connector 
16, are preferably integrally molded as a unit from a resinous plastic 
material, such as CAPRON.TM. nylon, available from Allied-Signal 
Engineered Plastics of Morristown, N.J. or VYDINE.TM. nylon from Monsanto 
Plastics of St. Louis, Mo. As shown in FIGS. 1-3, mirror housing 12 
preferably includes a solid or imperforate aerodynamically shaped rear 
wall 18 and a continuous peripheral wall 20 including top 20a, bottom 20b, 
and left and right end walls 20c, 20d, respectively. Wall 20 terminates in 
a peripheral edge 22 which defines a rearwardly facing opening 24 to the 
interior space 26 within housing 12 in which a pivotally adjustable 
reflective mirror unit is mounted. 
As is best seen in FIGS. 2 and 3, the interior of housing 12 includes a 
series of upstanding supports or posts 28 on which is mounted an actuator 
unit 30 on the inside surface of rear wall 18. Actuator 30 provides a 
pivot support for pivotal adjustment of a mirror element subassembly or 
unit 40 which is adapted for either manual or electrical actuation from a 
remote location. As shown in FIGS. 2 and 3, mirror assembly 10 includes a 
manually adjustable actuator including a three cable, Bowden-wire unit 42 
including cables 42a, 42b and 42c leading to a joy stick controller 44 
which extends through connecter 16 and support 14 into the interior of the 
vehicle adjacent the driver's position for actuation by a driver of the 
vehicle. Actuator 30 includes a pivot 46 (FIG. 3) providing a center of 
rotation for mirror unit 40 with respect to the actuator regardless of 
whether the actuator is manually or electrically operable. As will be 
understood, various types of electrical actuators may be used in mirror 
assembly 10 as substitutes for the manual actuator unit 30. Generally, 
such electrical actuators include one or a pair of electrical motors which 
operate extendible/retractable drive posts engaging the rear of the mirror 
unit at a pair of spaced locations to provide universal pivotal adjustment 
of the mirror unit about pivot center 46. Such actuators are connected 
electrically by wiring extending through hollow connector 16 and support 
14 to the vehicle electrical system and an appropriate switch or 
electrical controller mounted on the instrument panel or door of the 
vehicle. 
As is best seen in FIGS. 2, 3, 5 and 6, mirror unit 40 preferably includes 
a planar or curved reflective mirror element formed from an optically 
clear, planar or bent glass or plastic sheet having either a first or 
second surface reflective layer thereon. In the preferred embodiment, a 
metallic reflective layer containing chrome and other metals as is 
conventionally known is provided on the second or rear surface 52 of the 
mirror element 50 while the first surface 54 of the mirror element is 
uncoated. 
Alternately, variable reflectance, electro-optic mirror elements could be 
used as mirror element 50, such as an electrochromic cell of either the 
solid-state type or electrochemichromic type. Such an element is an 
electrochromic mirror cell which includes a transparent, front glass sheet 
and a transparent, rear glass sheet having a reflective coating applied to 
its rear surface. The front glass and reflective rear glass are slightly 
offset relative to one another such that the upper and lower edges project 
for connection to appropriate metal connection strips. A variable light 
transmittance, electrochromic layer is sandwiched in the space between the 
front glass and rear glass. The front surface of the rear glass and rear 
surface of the front glass each have a transparent electroconductive 
coating, such as indium tin oxide or doped tin oxide or the like, to 
conduct electricity across the full contact extent of the electrochromic 
layer from the connection strips secured at the offset top and bottom of 
the front and rear glass sheets. When controlled by a suitable electrical 
circuit, electrical voltage is applied across electro-optic cell between 
the front glass and the rear glass causing a variation in the 
transmittance of the electrochromic layer such as darkening or opacity to 
reduce the light reflected by the reflective rear glass. The 
electrochromic layer may, for example, be an electrochromic layer such as 
is described in commonly-assigned U.S. Pat. Nos. 5,140,455 and 5,151,816 
or in the following publications: N. R. Lynam, "Electrochromic Automotive 
Day/Night Mirrors", SAE Technical Paper Series, 870636 (1987); N. R. 
Lynam, "Smart Windows for Automobiles", SAE Technical Paper Series, 900419 
(1990); N. R. Lynam and A. Agrawal, "Automotive Applications of 
Chromogenic Materials", Large Area Chromogenics: Materials and Devices for 
Transmittance Control, C. M. Lampert and C. G. Granquist, EDS., Optical 
Engineering Press, Washington (1990), the disclosures of which are each 
hereby incorporated by reference herein. 
Mirror element 50 is preferably retained and held in a mirror support or 
backing plate 56 including a solid or imperforate rear wall 58 and a 
peripheral, upstanding side wall or rim 58 which extends generally 
perpendicularly outwardly from rear wall 58. Peripheral side wall or rim 
60 terminates in a generally bulbous or rounded peripheral edge 62 which 
is formed over and extends inwardly along the front surface 54 of mirror 
element 50 a predetermined distance to hold mirror element 50 against a 
series of upstanding supports or posts 64 extending toward the mirror 
glass from the inside surface of rear wall 58. Thus, mirror support 56, 
which is preferably molded from ABS resinous plastic, provides a hollow 
interior space 66 between the inside surface of rear wall 58 and the rear 
surface 52 of reflective mirror element 50. As shown in FIGS. 2 and 3, 
when pivotally mounted on pivot 46 in actuator unit 30, mirror unit 40 may 
be pivotally adjusted via the adjustment cables 42 and controller 44 to 
the left or right and upwardly or downwardly, the extremes of such pivotal 
movement being shown in broken lines in those drawings figures. As shown 
therein, during such pivotal movement, the outside surface of peripheral 
side wall 60 and perimeter 62 define a variable distance with the inside 
surface 19 of mirror housing 12 depending on the position of the mirror 
unit. For example, as shown in FIG. 2, the left end of mirror unit 40 is 
closer to the inside surface 19 of mirror housing 12 when pivoted toward 
the left than when it is pivoted fully to the right when the left end 
extends slightly outwardly of the housing. Similarly, the upper and lower 
edges of the mirror unit 40 are at varying distances with respect to the 
inside surface 19 of housing 12 depending on the specific pivotal 
position. 
As shown in FIGS. 1, 2, 4 and 6, mirror assembly 10 preferably includes a 
pair of vibration dampeners or stabilizers 70, 72 which are each mounted 
for sliding movement with respect to rear surface 59 of rear wall 58 of 
mirror support 56 and extend outwardly preferably along the axes of 
rotation of pivot center 46. As is best seen in FIGS. 4 and 6, each 
vibration dampener or stabilizer 70, 72, which may have differing overall 
lengths as shown in FIG. 4, is preferably formed from a relatively thin 
sheet of low friction coefficient resinous plastic such as MAGNUMTM ABS 
plastic available from Dow Chemical Company of Midland, Michigan, and 
includes opposed, generally parallel side edges 70a, 70b and 72a, 72b, a 
front mirror housing engaging edge 70c, 72c and a rear spring engaging 
edge 70d, 72d. Preferably, stabilizers 70, 72 comprise elongated resinous 
plastic fingers having a reduced width front portion 70e, 72e terminating 
in housing engaging edge 70c, 72c. The reduced width portions 70e, 72e 
define shoulders 70f, 72f on either side, which shoulders extend outwardly 
to the generally parallel side edges to provide stop engaging surfaces to 
limit extension of the stabilizer fingers beyond the peripheral side edge 
of the mirror support 56 as explained more fully below. 
As shown in FIGS. 4-7, each stabilizer finger 70, 72 is preferably mounted 
to extend in a different direction at a different location on the rear 
surface 59 of mirror support 56 such that it is slidably mounted generally 
parallel to the rear surface 59 but extends beyond the peripheral edge 60, 
62 for engagement with the inside surface of the mirror housing. The 
stabilizer fingers are respectively, slidably mounted in slide mounts 74, 
76, each slide mount including a pair of spaced slide flanges 74a, 74b and 
76a, 76b. Each slide mount includes a pair of rectilinear grooves 78, one 
on the inside surface of each slide flange 74a, 74b, 76a, 76b, as shown in 
FIG. 7. The side edges of the stabilizer fingers 70, 72 are fitted within 
grooves 78 for sliding movement generally parallel to rear surface 59. In 
addition, each slide flange includes an inwardly extending stop or limit 
surface 80a, 80b, 82a, 82b, as shown in FIG. 4. Stop surfaces 80, 82 
engage shoulders 70f, 72f to limit the sliding extension of stabilizer 
fingers 70, 72 and to maintain contact with the biasing spring as 
explained more fully below. When housing engaging edges 70c, 72c are 
engaged with inside housing surface 19, shoulders 70f, 72f are spaced from 
stop surfaces 80, 82 to provide space for additional extension of fingers 
70, 72 in the event the gap between the edge 60, 62 and housing surface 19 
increases as the mirror unit 40 is pivoted. 
As is best seen in FIGS. 4 and 6, stabilizing fingers 70, 72 are biased 
outwardly in slide mounts 74, 76 by means of a single hairpin-type spring 
90 preferably formed from spring steel. Spring 90 simultaneously engages 
the rear edges 70d, 72d of each stabilizing finger to provide 
substantially equal force and loading, urging the fingers 70, 72 
outwardly. Hairpin-type spring 90 includes a central circular section 92 
from which a pair of elongated spring ends extend outwardly at generally 
at an angle of about 90.degree. to one another when not under load. Spring 
ends 94, 96, which have generally the same length, are adapted to engage 
the rear edges of stabilizing fingers 70d, 72d and push or bias the spring 
fingers slidably outwardly until housing engaging edges 70c, 72c engage 
spaced portions of the inside surface 19 of the housing 12. One or more 
types of mounting structures for supporting spring 90 may be used. 
Preferably, as shown in FIGS. 4 and 6, a cylindrical mounting post or 
spring support 98 is molded to extend outwardly from the rear surface 59 
of mirror support 56 and includes a reduced diameter section near its 
outer end over which the center section 92 of spring 90 is placed and 
retained by a threaded fastener 100. Preferably, slide mounts 74, 76 and 
fingers 70, 72 are spaced approximately equidistantly from the center of 
axis of post 98 and on the axes of rotation of pivot center 46 as shown in 
FIG. 4. Spring ends 92, 94 may be retained against the rear edge 70d, 72d 
of stabilizing fingers 70, 72 by means of rearwardly extending, U-clamp 
flanges 71 which are formed on or attached to rear edges 70d, 72d defining 
a spring end receiving space therebetween. Alternately, the end or rear 
edges 70d, 72d of stabilizers 70, 72 may be widened or thickened to 
provide a secure contact surface for spring ends 92, 94. 
As will now be understood from FIGS. 4 and 6, when mirror unit 40 is 
pivotally mounted within mirror housing 12 on actuator unit 30 on pivot 
center 46, stabilizer fingers 70, 72 are slidably mounted in slide mounts 
74, 76 such that the front, housing surface engaging edges 70c, 72c extend 
beyond the peripheral side edge of mirror support 56 for engagement with 
the interior surface 19 of housing 12. Spring 90 is mounted on post 98 via 
fastener 100 such that spring ends 94, 96 are held by flanges 71 and 
engage the rear edges 70d, 72d of stabilizer fingers 70, 72 to urge them 
outwardly. The length of each stabilizer finger 70, 72 is predetermined 
such that, when mounted in slide mounts 74, 76, the housing engaging edge 
70c, 70d will extend a sufficient distance to engage the inner housing 
surface at all times, regardless of the pivotal position of mirror unit 40 
as shown in FIGS. 2 and 3. When the gap between the peripheral edge of 
mirror unit 40 and the inside surface 19 of housing 12 becomes smaller as 
the mirror unit is pivoted, the stabilizing fingers 70, 72 slide along the 
housing surface and are forced inwardly against the biasing force of 
spring 90, which force is generally equivalent on each of the stabilizing 
fingers because each engages approximately the same length spring end. 
Likewise, when the gap increases as the mirror unit is pivoted, spring 
ends 94, 96 urge fingers 70, 72 outwardly to maintain edges 70c, 70d in 
contact with inside housing surface 19. 
Preferably, spring 90 provides a force within the range of between about 3 
and 15 Newtons acting against each of the stabilizing fingers in 
directions generally parallel to the mirror element and surface 59 via 
spring ends 94, 96. Prior to mounting of the mirror unit 40 in the mirror 
housing, however, stabilizing fingers 70, 72 are maintained in engagement 
with spring ends 94, 96 by shoulders 70f, 72f engaging stops 80, 82 in the 
slide mounts to prevent the spring from forcing the stabilizing fingers 
out of slide mounts 74, 76. As will also be apparent, the stabilizing 
fingers can slide inwardly different distances at the same time against 
spring ends 94, 96 such that the gap between the top, bottom or end edges 
of the mirror unit and the inside surface of the mirror housing need not 
be uniform or equivalent at the positions of the stabilizing fingers. Use 
of the stabilizing fingers of the present invention provides a reduction 
in vibration of the mirror element within the housing such that visibility 
of images in the mirror is substantially improved. 
With reference to FIGS. 8 and 9, the vibration dampeners or stabilizers may 
be mounted on the mirror support in space 66 between the reflective mirror 
element and the inside surface 61 of the mirror support 56. As shown in 
FIG. 8, mirror unit 110 of the alternative embodiment of the present 
invention preferably includes a plurality of stiffening ribs 112, 114, 
116, 118, 120, 122 and 124 which extend at 90.degree. to one another and 
also serve as slide mounts or guides for stabilizing fingers 130, 132. 
Each stabilizing finger 130, 132, like stabilizers 70, 72, is preferably 
formed from a thin sheet of resinous, polymeric material, such as ABS 
plastic and includes a pair of generally parallel side edges 130a, 130b, 
132a, 132b, a front mirror housing engaging edge 130c, 132c and a rear 
edge 130d, 132d. Mirror housing engaging edge 130c, 132c is formed on a 
reduced width section 130e, 132e which define shoulders 130f, 132f 
extending at 90.degree. to the side edges and are adapted to engage stop 
or limit surfaces on the mirror support 56'. 
Stabilizing fingers 130, 132 are preferably slidably mounted between 
parallel ribs or slide guides 10, 122 and 116, 118 such that they extend 
in directions which are perpendicular to one another while extending 
beyond the peripheral edge of mirror support 56'. Mirror support 56' is 
also provided with a rectangular projection 134 having a stop surface 134a 
adapted to engage shoulder 130f to limit the outward extension of the 
stabilizer finger 130. Reduced width portion 130e of finger 130 projects 
through an aperture 136 (FIG. 8) in the upstanding side wall or rim 60' of 
mirror support 56'. Likewise, reduced width portion 132e of finger 132 
extends through a similar aperture 138 (FIGS. 8 and 9) in the upstanding 
side wall 60' of mirror support 56' at a spaced location along the side 
wall. Shoulder 132f engages the inside surface of the peripheral side wall 
60' adjacent aperture 138 to form a stop surface limiting extension of 
stabilizer finger 132 within guides 116, 118. 
As is best seen in FIG. 8, a hairpin-like spring 140 similar to spring 90 
engages both stabilizers 130, 132 to urge them outwardly such that edges 
130c, 132c engage spaced inside surface portions of the mirror housing for 
dampening vibration of the mirror unit 110. Spring 140 includes a 
coil-like circular center section 142 and outwardly extending end portions 
144, 146, each of which has approximately the same length and is inserted 
in a corresponding aperture 145, 147 in stabilizer 130, 132, respectively, 
for receiving the spring ends. Apertures 145, 147 open through sides 130b, 
132a adjacent openings or recesses 148, 150 in ribs 122, 116, 
respectively, allowing the spring ends 144, 146 to project through the 
ribs or guides for access and loading of stabilizers 130, 132. Like 
cylindrical post 98 in embodiment 10, mirror unit 110 includes an 
upstanding circular projection or spring support 152 about which center 
section 142 of spring 140 is wrapped for mounting and location 
intermediate the stabilizers. Although somewhat offset from the axes of 
rotation of mirror unit 110 when mounted in a mirror housing, stabilizers 
130, 132 are preferably spaced approximately equidistantly from the center 
or axis of spring support 152. Since projection 152 is formed on the 
inside surface of mirror support 56', and reflective mirror element 50' is 
secured within the inwardly projecting lip of perimeter rim 62', after 
mounting of the spring 140 and stabilizers 130, 132, no separate fastener 
is required to hold the spring in place after mirror element 50' is 
secured on the mirror support. As in embodiment 10, spring 140 in mirror 
unit 110 provides generally equivalent loading simultaneously of 
stabilizers 130, 132 such that each projects beyond the perimeter edge of 
the mirror unit into engagement with the mirror housing inside surface as 
limited by shoulders 130f, 132f engaging projection surface 134a and the 
inside of peripheral rim 60' adjacent aperture 138. As the gap or space 
between the edge of the mirror unit and the inside housing surface changes 
during pivotal adjustment of the mirror unit in the housing, the 
stabilizers 130, 132 independently retract against the force of the spring 
ends which provide constant force urging them outwardly to maintain the 
vibration dampening. As in embodiment 10, spring ends 144, 146 of spring 
140 are adapted to provide a force generally within the range of the 
between about 3 and 15 Newtons urging each of the stabilizers outwardly 
until as limited by the shoulders and stop surfaces. 
A third embodiment of the mirror unit subassembly including another form of 
vibration dampener/stabilizer is shown at 170 in FIGS. 10-14. In this 
embodiment, modified slide mounts 172, 173 are molded on mirror support 
171 from ABS plastic. Each slide mount 172, 173 includes a pair of spaced, 
slide guides or flanges 174, 176, and 175, 177 each of which is generally 
L-shaped in cross section and includes a vertical wall 174a, 176a or 175a, 
177a and a laterally extending top wall 174b, 176b or 175b, 177b. Top 
walls 174b, 176b, and 175a, 177a extend inwardly toward one another to 
define an interior space 179 in which is fitted a generally rectangular 
stabilizer 190. An upstanding, triangularly shaped projection 178 extends 
upwardly within the interior space and includes an inclined surface 180 
and a vertical face 182. 
As is best seen in FIGS. 11 and 12, stabilizers 190 are each generally 
rectangular and molded from a resinous plastic material, such as ABS 
plastic, and have a main body portion 191 with a generally U-shaped, 
downardly opening, cross section formed by downwardly extending side 
flanges 192, 194 which extend rearwardly from a forward, bulbous mirror 
housing engaging surface 196. Body portions 191 may be of different 
lengths to fit in different length slide mounts 172, 173, but still extend 
beyond the edge of mirror support 171 while extending inwardly beyond the 
inner ends of slide flanges 174,176 or 175, 177 to engage spring ends 216, 
218 as explained below. Surface 196 extends transversely across the front 
of the stabilizer body and has a rounded outer surface for sliding 
engagement with the mirror housing. A triangular projection 198 extends 
downwardly in the center of the U-shaped opening and has a vertical face 
200 and an inclined surface 202. Surface 198 is adapted to engage surface 
182 on projection 178 when stabilizer 190 is mounted within guide flanges 
174, 176 to limit extension of the housing engaging edge 196 in the same 
manner as do shoulders 70f, 72f, 130f, and 132f in embodiments 10 and 110. 
Inclined surfaces 180, 202 are adapted to ride over another in cam-like 
fashion when stabilizer 190 is slidably inserted in the opening 179 from 
adjacent the perimeter edge of mirror unit 170 during installation. Once 
projection 200 is cammed over projection 178, vertical faces 182, 198 
engage one another to prevent removal of the stabilizer from the slide 
mount and limit extension. 
As in embodiments 10, 110, a single hair-pin like spring 210 similar to 
springs 90, 140 has a coil-like center section 214 mounted about 
cylindrical projection or spring support 212 with spring ends 216, 218 of 
generally the same length respectively engaging the rear edges of 
stabilizers 190 to urge them simultaneously outwardly as limited by 
surfaces 182, 198. Stabilizers 190 and slide mounts 172, 173 are 
preferably spaced approximately equidistantly from the axis of spring 
support 212, preferably on the axes of rotation or pivotal movement of 
mirror support 171 when mounted in a mirror housing. Otherwise, 
stabilizers 190 may be substituted for any of the stabilizers or dampeners 
70, 72, 130, or 132 in either embodiment 10 or 110. 
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 of the invention shown in the drawing 
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.