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Title:
MIRROR HOUSING PIVOTING MECHANISM FOR A VEHICLE REAR VIEW MIRROR
Document Type and Number:
WIPO Patent Application WO/1991/004172
Kind Code:
A1
Abstract:
An electrically operable pivoting mechanism for the mirror housing of a rearview mirror comprises a carrier member (7) to be fixedly connected to a vehicle, an instrument housing (16, 17) mounted for rotation on said carrier member (7), and fixedly connected to the mirror housing by means of attachment eyes (19). Mounted in the instrument housing (16, 17) is a motor (13) and a speed reductor (14). The power output shaft (12) of the speed reductor (14) is connected through a spring-biased friction clutch (26, 27) to the carrier member (7). The pivot axis (6) of the pivoting mechanism coincides with the axis of the speed reductor (14). Arranged between carrier member (7) and instrument housing (16, 17) is a friction damper (9, 10, 20) to provide a vibration-free arrangement or connection.

Inventors:
Oskam
Aane
Adriaan
Application Number:
PCT/NL1990/000133
Publication Date:
April 04, 1991
Filing Date:
September 14, 1990
Export Citation:
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Assignee:
Iku, Holding Montfoort B.
Oskam, Aane Adriaan
International Classes:
B60R1/074; (IPC1-7): B60R1/06
Foreign References:
GB2157387A
DE3820578A1
EP0209666A2
Other References:
PATENT ABSTRACTS OF JAPAN vol. 9, no. 313 (M-437)(2036) 10 December 1985, & JP-A-60 148737 (ICHIKOH KOGYO K.K.) 06 August 1985, see the whole document
PATENT ABSTRACTS OF JAPAN vol. 9, no. 294 (M-431)(2017) 20 November 1985, & JP-A-60 131344 (ICHIKOH KOGYO K.K.) 13 July 1985, see the whole document
PATENT ABSTRACTS OF JAPAN vol. 9, no. 313 (M-437)(2036) 10 December 1985, & JP-A-60 148736 (ICHIKOH KOGYO K.K.) 06 August 1985, see the whole document
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Claims:
CLAIMS
1. A mirror housing pivoting mechanism for a vehicle rear view mirror, comprising a carrier member to be fixedly connected to a vehicle; an instrument housing mounted for rotation on said carrier member and adapted to be connected to the mirror housing; a motor with a speed reductor, mounted in said instrument housing and having an output shaft connected by means of a friction clutch with said carrier member, characterized in that the pivoting axis of the pivoting mechanism (5) coincides with the axis of the reductor unit (14) .
2. A pivoting mechanism as claimed in claim 1, characterized in that the carrier member (7; 107) is provided at the top with a raised cylindrical rim (9; 109) to form a laterally projecting collar (10; 110), which rim (9; 109) can be received with a sliding fit in a cylindrical hole at the bottom of the instrument housing (15; 115), whose lower edge (20; 120) is springbiased into contact with said projecting collar (10; 110) .
3. A pivoting mechanism as claimed in claims 12, characterized in that the output shaft (112) of the speed reductor extends through a central aperture (111) of the carrier member (107) , the part projecting outside the carrier member being surrounded by a friction clutch built up from discs, one part (165) of which clutch is coupled with a keyway (125) provided to extend axially in said projecting part, and the other part (166) of which is coupled with a keyway provided in said carrier member (107) said clutch being 5 springbiased by means of a Belleville washer (163) .
4. A pivoting mechanism as claimed in claims 12, characterized in that the carrier member (7) is provided at its bottom surface with radially extending projections (3) , and a ring (26) provided with complementary projections is 0 springbiased into surfacetosurface contact with said bottom surface under the influence of a compression spring (27), the output shaft (12) of the speed reductor (14) extending through a central hole (22) of the carrier member (7), and its part extending outside the carrier member (7) being surrounded a 15 compression spring (27) enclosed between said ring (26) provided with projections and a retaining disc (28) mounted on the end of said output shaft (12) , said ring (26) being connected to the output shaft (12) of the speed reductor (14) so as to be restrained from rotation relative to it. 20 5.
5. A pivoting mechanism as claimed in any one of claims 14, characterized in that the output shaft (12) of the speed reductor (14) has an internally toothed cup (24) supported through an axial/radial bearing (23) on a partition (21) of the instrument housing (15), which housing, when the motor 25 (13) is energized, can rotate about the stationary output shaft (12) of the speed reductor (14) and the raised cylindrical edge (9) of the carrier member (7) .
6. A pivoting mechanism as claimed in any one of claims 15, characterized in that the drive mechanism (13, 14; 113, 114) is arranged to be blocked, in the event the mirror housing is subjected to mechanical impact, at at least three points (P, Q ,R) within the speed reductor (14, 114), said speed reductor being formed as a planetary transmission.
7. A pivoting mechanism as claimed in any one of claims 16, characterized by two microswitches (45, 46) accommodated in the wall of the instrument housing (15) , each said switches having a switch pin (47, 48), whose free end can project into a control groove (49, 50) formed in the raised edge (9) of the carrier member (7) .
8. A pivoting mechanism as claimed in claim 7, characterized in that the control grooves (40, 50) of the two switch pins (47, 48) are spaced apart both circumferentially and axially of the pivoting mechanism (5) .
9. A pivoting mechanism as claimed in claims 78, characterized in that the control grooves are formed so that in the normal position of the mirror housing (1) the first microswitch is in the "off" position and the second microswitch is in the "on" position, whereas in the pivoted position the second microswitch (46) is in the "off" position and the first (45) is in the "on" position.
Description:
Title: Mirror housing pivoting mechanism for a vehicle rear view mirror

This invention relates to a mirror housing pivoting mechanism for a vehicle rear view mirror, said mechanism comprising a carrier member to be fixedly connected to a vehicle, an instrument housing mounted for rotation on said carrier member and adapted to be connected to the mirror housing, and a motor with a speed reductor, mounted in said instrument housing and having an output shaft connected by means of a friction clutch with said carrier member.

Rear view mirrors for vehicles are often provided with mirror adjusting instruments housed within the mirror housing, and capable of adjusting the mirror about two mutually perpendicular axes in order that the mirror may thus be adapted to the size and sitting position of the driver of the vehicle. For safety reasons, the mirror housing itself is usually pivotable about an axis located close to the vehicle, so that upon an impact on the mirror housing, the housing can fold down about the pivoting axis and may continue to occupy such folded-down position approximately parallel to the vehicle, or return to its original normal position under the influence of re-set springs.

In accordance with the increasing need for the use of electrically operated instruments in vehicles, the wish has arisen that the mirror housing can be made to fold down by the driver from the position behind the wheel, i.e. without leaving the vehicle. This offers the advantage that the

overall width of the vehicle can be reduced and, for example, when parking the vehicle, less space is occupied, or the vehicle can be placed closer to the wall of a garage. An electrically operable fold-down mechanism for a mirror housing is disclosed, for example, in United States patent specification 4,786,156.

It is an object of the present invention to provide a mirror housing pivoting mechanism of the above type which satisfies the following requirements: - the pivoting mechanism must not involve an increase in size of the mirror housing, and should accordingly be of very compact construction; - in the "normal" position of the mirror housing, a vibration-free suspension must be ensured; and - the pivoting mechanism must be capable of placing the mirror housing electrically both in a "normal" service position and in a folded-down position, while the pivoting mechanism must not experience any adverse effect upon the occurrence of mechanical impact on the mirror housing.

The pivoting mechanism according to the present invention is characterized in that its pivoting axis coincides with the axis of the reductor unit . In this way the most compact form imaginable of the pivoting mechanism is obtained. During the pivoting movement cf the mirror housing by electrical means, as contemplated, the housing can pivot about the stationary output shaft of the speed reductor, which in

that case is "fixedly" connected to the carrier member. During this movement the instrument housing is rotated relative to the carrier member. To provide a vibration-free arrangement, a friction damper is provided between the instrument housing and the carrier member, which friction damper preferably consists of a raised cylindrical rim provided at the top of the carrier member to form a laterally projecting collar, which rim can be received with a sliding fit in a cylindrical hole at the bottom of the instrument housing, whose lower edge is spring- biased into contact with said projecting collar.

In the case of mechanical impact forces exerted on the mirror housing, the mirror housing must also be able to pivot about the stationary carrier member when the drive system is blocked. This movement is possible by means of the friction clutch provided between the output shaft and the carrier member, which friction clutch preferably consists of radially extending projections provided on the bottom surface of the carrier member and a ring provided with complementary projections, which is spring-biased into surface-to-surface contact with said bottom surface under the influence of a compression spring, the output shaft of the speed reductor extending through a central hole of the carrier member, and its part extending outside the carrier member being surrounded by a compression spring enclosed between said ring provided with projections and a confining disc mounted on the end of the output shaft, said ring being connected to the output

shaft of the speed reductor so as to be restrained from rotation relative to it .

In a variant embodiment, the friction clutch is built up from discs. In order that the drive mechanism may be protected from damage when loaded in the blocking direction, blocking is preferably effected at at least three points within the speed reductor, which takes the form of a planetary transmission. By virtue of this arrangement, the blocking points may be spaced a relatively large distance from the axis of the reductor unit while retaining a compact construction. Furthermore, blocking at three points makes it possible to use gear wheels of plastics material. In a one-point blocking arrangement, as used in the mechanism of US-A-4,786, 156, metal gear wheels must be used to avoid the breakage of teeth.

Some embodiments of the pivoting mechanism according to the invention will now be described, by way of example, with reference to the accompanying drawings. In said drawings,

Fig. 1 illustrates a top plan view of a rear view mirror mounted in a mirror housing, and showing the position of the pivoting mechanism within the mirror housing;

Fig. 2 is a front elevational view of the instrument shown in Fig. 1;

Fig. 3 is a top plan view of the pivoting mechanism; Fig. 4 is a cross-sectional view of the mechanism, taken on the line IV-IV of Fig. 3;

Fig. 5 shows a side-elevational view of the mechanism of Fig. 4;

Fig. 6 shows a cross-sectional view, taken on the line VI-VI of Fig. 4; Fig. 7 shows a cross-sectional view, taken on the line VII-VII of Fig. 4;

Fig. 8 shows a cross-sectional view, taken on the line VIII-VIII of Fig. 4;

Fig. 9 shows a cross-sectional view, taken on the line IX-IX of Fig. 4;

Fig. 10 shows a cross-sectional view, taken on the line X-X of Fig. 4;

Fig. 11 shows a bottom view of the showing of Fig. 4;

Fig. 12 shows a simplified electrical block diagram; Fig. 13 shows a printed-wiring mounting plate to be mounted within the instrument;

Fig. 14 shows a cross-sectional view similar to Fig. 4, and showing a variant of the pivoting mechanism;

Fig. 15 shows a cross-sectional view, taken on the line XV-XV of Fig. 14; and

Fig. 16 shows a perspective elevational view of a mirror housing with a pivoting mechanism as illustrated in Figs. 14-15.

Figs. 1-2 illustrate a mirror housing 1 with a rear view mirror 2 mounted therein. Mirror housing 1 is connected in one way or another to a vehicle body by means of a support 4. Shown schematically behind mirror 2 is a mirror adjusting

instrument 3, which with the mirror housing being stationary, is capable of pivoting mirror 2 about two mutually perpendicular axes X, Y. Shown within the mirror housing is a pivoting mechanism 5 with a pivot axis 6, about which the mirror housing can be pivoted or folded down relative to support 4, which can be connected to a vehicle.

The pivoting mechanism (Fig. 4) comprises a carrier member 7, which in one way or another is fixedly connected to support 4 mounting mirror housing 1. For this purpose, three tapped holes 8 are formed in the bottom edge of the carrier member 7 for receiving screws (see Fig. 2) . At the top, the carrier member is provided with a raised cylindrical rim 9 which relative to the circumference of carrier member 7 is off-set radially inwardly to form a collar 10. In the centre of the carrier member there is a central hole 11 to permit the passage of output shaft 12 of the drive unit of the mechanism, which comprises a motor 13 and a speed reductor 14. Drive unit 13, 14 is accommodated in an instrument housing 15 which consists of a bottom section 16 and a top section or cap 17. Housing sections 16, 17 are interconnected by means of bolts

18 (Fig. 3) . Section 16 is provided at one side with two pairs of connecting eyes 19 for mounting mirror housing 1 thereon.

The raised cylindrical rim 9 of the carrier member 7 extends into the cylindrical hole of the bottom section 16 of the housing, with the bottom edge 20 of section 16 being in contact with collar 10 of carrier member 7. Rims 9 and 10 are a sliding fit one within the other, so that the instrument

housing 15 is rotatable relative to carrier member 7. Provided in the bottom section 16 of instrument housing 15 is a partition 21 with a central aperture 22 to permit the passage of the power output shaft 12 of speed reductor 14. Mounted in aperture 22 is an axial/radial bearing 23 for supporting the cup-shaped end 24 of the power output shaft 12 of the two-step speed reductor 14, to be described more fully hereinafter. The bottom part of output shaft 12 is provided with one or more keyways 25, over which a ring 26 is axially slidable, which ring 26 is provided with lands which can slide in keyways 25. The ring 26 is biased into contact with the bottom surface of the carrier member 7 by means of a compression spring 27, the lower end of which is in abutment with a hold-down plate 28, which rests on a retaining ring 29 provided at the end of output shaft 12.

The bottom surface of the carrier member 7 (see Fig. 10) is provided with radially extending projections 30 which are trapezium-shaped in cross section. The top surface of ring 26 is provided with complementarily shaped radially extending projections, which projections are pressed by spring 27 into the valleys of the bottom surface of the carrier member 7. In this way, ring 27 can only slide in the circumferential direction relative to carrier member 7 if relatively large forces are exercised on it, for example, impact forces exerted on the mirror housing 1 connected to the connecting members 19. In that case, ring 26 will move over one or more projections 30 and may possibly continue to occupy an

intermediate position. In such intermediate position, the projections 30 of carrier member 7 and the complementary projections of ring 26 will no longer be in mesh with each other. Provided between the bottom surface of carrier member 7 and the top surface of ring 26 is a metal liner 31, whose shape is adapted to the shape of the bottom surface of the carrier member 7.

The electrical adjustment of the mirror housing from the "normal" position to the parking position, or the other way round, is effected by means of the drive unit consisting of motor 13 and speed reductor 1 . Speed reductor 14 consists of a two-step planatary reduction system best shown in Figs. 4, 6 and 7. The first stage 32 of the speed reductor 14 comprises two planet wheels 33 meshing with a gear wheel 34 mounted on the power output shaft of motor 13 and, on the other hand with a toothed ring 35 mounted on the inner wall of a cup-shaped disc 35a confined within the top housing section 17. Planet wheels 33 are mounted on a planet carrier 36 which is provided with a gear wheel 37, which forms the sun wheel for the second stage 38 of the speed reductor 14. This sun wheel 37 meshes with three loose gear wheels 39 which are provided in axial direction with two different gears 40, 41 differing by a small number of teeth from each other, for example, one tooth. The top gear 40 is in engagement with teeth 42 provided on the inside of a bushing 16a provided within the bottom housing section 16, and the bottom gear 41 of each gear wheel 39

meshes with a gear 43 provided within the cup-shaped part 24 of the power output shaft 12.

The first stage 32 of the speed reductor 14 has a reduction of 16 to 1, and the second stage 38 of speed reductor 14 has a reduction of about 180 to 1, so that the total reduction of the speed reductor 14 is about 3000. This high reduction has the advantage that a small motor 13 can be chosen, which is capable of providing a relatively large torque at the power output shaft 12. In addition, the two- stage speed reductor 14 has the important advantage of providing a drive free from play, which at the three points P-Q-R (Fig. 7) is coupled with the cup 24 of the power output shaft 12, which points P-Q-R are in addition located a relatively large distance from the axis 6 of the mechanism. Operation: a. Normal adjustment

When motor 13 is energized, power output shaft 12 would begin to rotate with a reduction of about 3000 to 1, if it were not blocked by the meshing projections 30 of carrier member 7 and the complementary projections of ring 26.

Accordingly, power output shaft 12 is stationary, and motor 13, speed reductor 14 and the mirror housing 1 connected therewith through connecting members 19 rotate from the "normal" position (see Fig. 1 and Fig. 9) to the "parking position", in which mirror housing 1 is approximately parallel to the vehicle side wall. When motor 13 is energized in the reverse direction, mirror housing.1 is pivoted from the

"parking position" to the "normal" position shown in Fig. 9. During this pivoting movement of the mirror housing, the bottom rim 20 of the bottom housing section 19 rotates relative to the stationary collar 10 of carrier member 7. The "parking position" and the "normal" position of the mirror housing are set by means of two microswitches 45, 46, shown in Figs. 4 and 9. The switching pins 47, 48 of these microswitches 45, 46 run in control grooves formed on the cylindrical rim 9 of the carrier member 7. The switching pin 47 of microswitch 45 runs in control groove 49 and can run outside the control groove 49 over the outer wall of the cylindrical rim 9 of carrier member 7. The switching pin 48 of microswitch 46 normally runs over the outer wall of the cylindrical wall 9 of carrier member 7 and can move radially in control groove 50 shown dotted in Fig. 9. In the circumferential direction and in the axial direction, control grooves 49, 50 are spaced apart from each other. In the "normal" position of the mirror housing, microswitch 45 has just been switched off, and pin 47 of this microswitch 45 is located in the beginning of control groove 49. In this position, motor 13 can only be energized clockwise (see Fig. 12) whereby mirror housing 1 and hence the bottom housing section 16 are moved clockwise to the parking position, and the motor 13 is stopped as soon as switching pin 48 enters control groove 50. Pin 47 is in that case in abutment with the outer surface of the cylindrical rim 9 of carrier member 7, so that from the parking position, mirror housing 1 can only be

moved anti-clockwise to the normal position illustrated in Fig. 9.

It follows from the above-described "normal" adjustment of mirror housing 1 that there should be at least two different friction levels in the drive system: a high friction level between carrier member 7 and ring 26 to block output shaft 12. This high friction level is obtained by the trapezium-shaped run-on projections 30. - a lower "normal" friction level between the rim 20 of housing section 16 and collar 10 of the carrier member 7. This "normal" friction between rim 20 and rim 9/collar 10, which is always present, provides for the damping of any vibrations which may occur as a result of any play in the drive. b. Derangement as a result of impart forces on the mirror housing

Impact forces exerted on mirror housing 1 are passed through connecting eyes 19 to housing section 16, which at points P, Q, R (Fig. 7) is coupled to the two-stage speed reductor 14, which can only be driven in the direction motor 13 - output shaft 12 and is blocked in the opposite direction. Accordingly, housing section 16 cannot be displaced relative to carrier member 7. Through the drive blocked at points P, Q, R the output shaft 12 thereof is rotated through a given angle, thereby compressing spring 27, and causing the complementary run-on projections 30 in carrier member 7, on

the one hand, and ring 26, on the other, to slide over each other.

As a result of an impact load exerted on mirror housing 1, ring 26 can move into two different final positions relative to carrier member 7, namely

- a final position in which the complementary projections

30 in ring 26 and carrier member 7 are again in mesh with each other. Ring 26 has then shifted over a whole number of projections 30, and the same high friction level is present between parts 7, 26 as before the device was subjected to the impact load. In that case, mirror housing 1 can be returned into its normal or "parking position" in the above-described manner ("normal" adjustment) . - a final position in which the complementary projections 30 are not located within, but upon each other. Ring 26 has then shifted over a non-integral number of projections 30. In the case of electrical adjustment from this position, it must be ensured that first the power output shaft 12 is rotated with housing section 16 being stationary until the complementary projections 30 of parts 7, 26 are again in mesh, and subsequently, with continued energization of motor 13, housing section 16 is rotated relative to carrier member 7. Consequently, the frictional resistance between parts 7, 26 when projections 30 are on top of each other must be less than

the frictional resistance between rim 20 of housing section 16 and collar 10 of carrier member 7. At the bottom of carrier member 7, a multi-core electric cable 51 is passed into the instrument. Two cores serve to provide supply voltage to motor 13, and a multi-core cable 52 leaves the instrument to provide supply voltage and signals to the mirror adjusting instrument 3 for adjusting mirror 2 about two mutually perpendicular axes .

Fig. 12 illustrates a simplified wiring diagram for motor 13 by means of two end switches 45, 46. Provided parallel to each end switch 45, 46 is a diode 53, which diode blocks the supply of current to motor 13 when end switch 45 or 46 is in the open position. Motor 13 is switched on by means of a switch 45 provided within the vehicle. Fig. 13 shows a mounting plate 55 for mounting end switches 45, 46 thereon with the pertinent diodes, anti¬ jamming elements, etc. This mounting plate 55 is mounted in housing section 17 (see Fig. 4) .

The variant shown in Figs. 14-16 differs from the embodiment described above mainly in having a lower overall height as a result of the fact that the motor shaft is turned through 90°. The first stage of the speed reductor 132 is now a worm wheel transmission comprising a worm 161 mounted on the sdhaft of motor 113, which is in mesh with a worm wheel 160 mounted on a pin 162 in the modified cap 117. Provided on worm wheel 160 is a gear wheel 137, which forms the sun wheel for

the second stage 138 of the speed reductor, which is identical to that shown in Figs . 4 and 7.

Cap 117 is connected to the bottom housing section 116, whose rim 120 is rotatably in contact with the collar 110 of carrier member 107. Collar 110 is constituted by an L-section liner with a raised rim 109, in which switching tracks for microswitches are provided in the manner shown in Fig. 9.

The friction clutch shown in this variant also differs somewhat from that shown in Fig. 4. In this case the friction clutch consists of a series of discs 165, 166, one group 165 of which is coupled by means of a keyway 125 to the power output shaft 112, while discs 166 of the second group are connected by means of a keyway to the carrier member 107.

Discs 165, 166 are pressed together by means of a Belleville washer 163, which can be given a suitable bias by means of a hold-down bolt 164.