ACTUATOR

Abstract: There is described an actuator (10) for effecting a pivotal movement about two mutually perpendicular axes (6, 7), which actuator comprises one motor (14). A primary reduction step (20) is formed by a worm (21) and a worm wheel (22) which is coupled to a rotation-selective coupling (50) having two outputs. Each of those outputs is coupled to a secondary reduction step (30; 40), consisting of a worm (31; 41) and a worm wheel (32; 42). Via a pin/slot coupling (35; 36), each secondary worm wheel (32; 42) is coupled to a part (16) to be displaced.

Description: Title: Actuator The invention relates to an actuator having two outputs for effecting two different, mutually independent setting movements. The two outputs may be connected to two different objects for setting the positions of those two . objects independently of each other, but those two outputs may also be connected, at two different locations, with one object for effecting two different setting movements of that one object, for instance two pivotal movements about two different pivotal axes. More in particular, the present invention relates to such actuator having only one motor. Such actuator is in particular, but not exclusively, useful in a wing mirror for a motorcar, and will therefore hereinafter be described for such a practical example. Presently, various types of wing mirrors are known, in which a mirror plate is adjustably mounted in a mirror housing, the position of that mirror plate being adjustable by a pivotal movement about two substantially perpendicular pivotal axes, which pivotal movements can be remotely performed by the driver from the driver's seat by means of motors likewise mounted in that mirror housing. Conventionally, the mirror plate can be pivoted in four directions: up or down relative to a horizontal pivotal axis, and leftwards or rightwards relative to a vertical pivotal axis. More in particular, it is conventional that the mirror plate can be adjusted from any orientation in any of these four directions, which offers much ease of operation. However, a drawback of such actuators is that they require two motors, each capable of rotating in two directions, one motor operating the up/down displacements and the other motor operating the left/right displacements. Those two motors occupy relatively much space in the mirror housing, and render the actuator as a whole relatively expensive. Moreover, for operating those two motors, a likewise relatively expensive five-position switch is needed. There is a need for an actuator capable of setting a part such as a mirror plate in any position, both in horizontal direction and in vertical direction, but whose construction is considerably more inexpensive. To meet this need, actuators have already been proposed which have only one motor. Such one-motor actuators are based on a cyclic displacement in each of the two freedoms of movement, one freedom of movement (horizontal) being operated by causing the motor to rotate in one direction, while the other freedom of movement (vertical) is operated by causing the motor to rotate in the other direction. Hence, in such actuators, it is not possible to adjust a mirror plate from any orientation in any of the four directions mentioned. With regard to the horizontal freedom of movement, energization of the motor will result in a leftward pivotal movement until the leftmost position is reached; next, the mirror plate will perform a rightward pivotal movement until the rightmost position is reached, whereupon the direction of the pivotal movement is reversed again, and so on, which is referred to as a cyclic movement. Generally, a one-motor actuator therefore comprises first cyclic displacement means for effecting a cyclic movement of the part to be displaced in a first direction, second cyclic displacement means for effecting a cyclic movement of the part to be displaced in a second direction, and separation-transmission means which are coupled between the motor and the first and second cyclic displacement means for driving the first cyclic displacement means when the motor is rotated in one direction, and for driving the second cyclic displacement means when the motor is rotated in the other direction. German Offenlegungsschrift 4,321,847 describes a one- motor actuator in which a worm mounted on the output shaft of the motor drives two gear wheels. Via a one-direction coupling, each gear wheel drives a second worm. Each second worm drives a worm wheel coaxially coupled to a circular disk. A coupling rod to the mirror support plate is eccentrically mounted on that circular disk. This actuator has relatively many parts. Further, this actuator has the drawback that the motor must at all times drive two gear wheels which are both provided with a one-direction coupling, as a consequence of which the known actuator has a relatively low efficiency. Further, in this known actuator, the one-direction couplings are loaded rather heavily. In particular when used in a wing mirror, it is desired that the mirror plate can also be adjusted manually by exerting an external force, for instance in the event of a defect to the electric operating mechanism. For that purpose, the coupling rod of the known actuator is of a two-piece construction, the first bar-shaped part being capable of pivoting telescopically in the second part, which is substantially constructed as a hollow cylinder. The first bar-shaped part has its outer surface provided with ribs, and the second hollow cylindrical part has its inner surface provided with springing projections cooperating these ribs. When an external force is exerted, these projections move across these ribs, causing the axial length of the coupling bar to change. Two major drawbacks are inherent in this construction. In the first place, it is not possible to retrieve the original position with certainty by exerting an external force in opposite direction. In the second place, it is not possible to undo the manual change, i.e. the changed axial length of the coupling bar, by a subsequent electric adjustment, which means that after a manual adjustment, the adjusting range of the actuator has changed . Another example of a one-motor actuator is described in US Patent 4,474,428. In that actuator, a speed-reducing mechanism is arranged, in alignment with the motor shaft. Two drive disks are eccentrically mounted concentrically with the driven shaft of that speed-reducing mechanism, each drive disk being coupled to an output of an axial two- way coupling. One of those drive disks is disposed without play in a fork construction which is bearing-mounted in the mirror housing for a linear movement, while the other one of those drive disks is surrounded without play by a ring* which is connected, via a curved bar, to the mirror support plate. This known construction, too, has a number of drawbacks. Important disadvantages of this known construction are that the construction is fairly complicated and requires much space, and that the mirror cannot be adjusted manually. It is an object of the invention to overcome the above-mentioned drawbacks of the prior art. It is a general object of the present invention to provide a one-motor actuator which is simpler and more inexpensive. More in particular, it is an object of the present invention to provide a one-motor actuator having a small number of parts, which parts can be manufactured and assembled in a relatively simple manner. It is a further object of the present invention to provide an actuator which can also be manually adjusted such that the electric adjusting range has not changed after the adjustment, while the actuator can manually be returned into the starting position again with certainty. These and other aspects, characteristics and advantages of the present invention will be clarified by the following specification of a preferred embodiment of an actuator according to the invention, with reference to the accompanying drawings . In these drawings : Fig. 1 schematically shows a section of a wing mirror; Fig. 2 is a schematic perspective view of the moving parts in an embodiment of the actuator according to the present invention; Fig. 3A is a schematic side elevation of a detail of an actuator housing; Fig. 3B schematically shows a section taken on the line B-B in Fig. 3A; Fig. 4A schematically shows a longitudinal section of an embodiment of a secondary worm wheel ; Fig. 4B schematically shows a longitudinal section of another embodiment of a secondary worm wheel ; Fig. 5 shows a section, comparable with Fig. 3B, of a structural variant; Fig. 6 schematically shows a cross section of an embodiment of a rotation-selective coupling; Fig. 7A is a schematic perspective view of a detail of a structural variant of a rotation-selective coupling; Fig. 7B is a schematic perspective view of the structural variant illustrated in Fig. 7A, viewed from a different direction; Fig. 8A schematically shows a cross section, comparable with Fig. 6 , of a preferred embodiment of a rotation- selective coupling; Fig. 8B schematically shows a section taken on the line B-B in Fig. 8A; Fig. 9A is a top plan view of a practical embodiment of the actuator according to the present invention; Fig. 9B is a side elevation of the actuator of Fig. 9A; and Fig. 9C shows a cross section of the actuator of Fig. 9A. In the Figures, identical or comparable parts are designated by identical reference numerals. Because mirror-adjusting instruments for wing mirrors, for pivoting a mirror plate in two mutually perpendicular directions, are generally known, the construction thereof will hereinbelow be discussed only very schematically, with reference to Fig. 1, which schematically shows a horizontal section of a wing mirror 1. The wing mirror 1 comprises a bowl -shaped mirror housing 2, mounted via a base 3 on a vehicle, not shown. A mirror plate 4 is mounted on a mirror support plate 5 capable of pivoting relative to the mirror housing 2 about a vertical pivotal axis 6 and about a horizontal pivotal axis 7. The intersection S of the pivotal axes 6 and 7 is preferably located as close as possible to the surface of the mirror plate 4. Disposed in the mirror housing 2 is an actuator 10. The actuator 10 comprises an actuator housing 11 having a bottom part 12 and a cover part 13. The bottom part 12 of the actuator housing 11 is attached, for instance by screws, to the mirror housing 2, while the cover part 13 of the actuator housing 11 is attached, for instance likewise by screws, to the mirror support plate 5. The mirror support plate 5 may also form an integral part of the cover part 13 of the actuator housing 11. The cover part 13 connects to the bottom part 12 so as to be substantially dustproof, to protect the actuator components disposed in the actuator housing 11. Arranged in the actuator housing 11 and fixed relative to the bottom part 12 is a single electromotor 14, driving coupling means 17 to be described hereinbelow, which coupling means 17 engage, at an engagement point P, the cover part 13 of the actuator housing 11 in order to impart a movement to that cover part 13 in the direction designated by the arrow A, causing the mirror plate 5 and the mirror 4 mounted thereon to make a pivotal movement about the pivotal axis 6. In a comparable manner, coupling means are present which engage another point of the cover part for effecting a pivotal movement about the other pivotal axis 7, as will be appreciated by anyone skilled in the art and which is not shown in Fig. 1 for the sake of simplicity. Fig. 2 is a schematic perspective view of some important parts of the actuator 10, in their spatial orientation relative to each other. These parts are arranged in the actuator housing 11, not shown in Fig. 2 for the sake of clarity. The actuator 10 comprises a single motor 14, symmetrically disposed in the actuator housing. The motor 14 has electric connecting points which are not shown in Fig. 2 for the sake of simplicity, and can rotate clockwise or anticlockwise, depending on the voltage presented. The motor 14 has a driven shaft 15 mounting a primary worm 21. The primary worm 21 drives a primary worm wheel 22, which is also symmetrically arranged in the actuator housing 11. The combination of the primary worm 21 and the primary worm wheel 22 forms a first reduction step 20 of the actuator 10. Arranged on either side of the primary worm wheel 22 are two secondary worms 31, 41. The axes of rotation of the secondary worms 31, 41 are in line, substantially at right angles to the axis of rotation of the primary worm 21, and each drive a secondary worm wheel 32, 42. The combination of the first secondary worm 31 and the first secondary worm wheel 32 forms a second reduction step 30 of the actuator 10 with regard to a pivotal movement about one pivotal axis, while the combination of the second secondary worm 41 and the second secondary worm wheel 42 forms a second reduction step 40 of the actuator 10 with regard to a pivotal movement about the other pivotal axis. In principle, the two reduction steps 30, 40 are identical yet mirrored relative to each other, and symmetrically arranged relative to each other, for which reason only the reduction step 30 will be further discussed hereinbelow. Fig. 3A is a schematic side elevation of a portion of the actuator housing 11 at the location of the engagement point P, and Fig. 3B schematically shows a cross section of the first secondary worm wheel 32 at the location of the engagement point P. Coaxially mounted on the first secondary worm wheel 32 is a disk 33 whose circumferential face serves as bearing face for the first secondary worm wheel 32. Eccentrically mounted on the axial end face 34 of the disk 33 facing away from the first secondary worm wheel 32 is a pin 35. The cover part 13 of the actuator housing 11 comprises a wall portion 16 which is arranged at an angle to the mirror support plate 5 and which is provided with a slot 36 directed substantially parallel to the mirror support plate 5. The pin 35 engages in this slot 36. Preferably, the worm wheel 32 and the disk 33 form an integral part, while the pin 35 may also be manufactured integrally with the disk 33, so that the combination of worm wheel 32, disk 33 and pin 35 may form a single part which can readily be manufactured by, for instance, injection molding. It will be understood by anyone skilled in the art that a rotation of the worm wheel 32 via the coupling between pin 35 and slot 36 results in a reciprocating movement of the cover part 13 of the actuator housing 11 in the direction A, i.e. a reciprocating pivotal movement of the mirror support plate 5. The actuator 10 can be of such design that the secondary worm wheel 32 is at all times coupled via the pin 35 and the slot 36 to the wall portion 16 of the cover part 13 of the actuator housing 11, if the possibility of a manual adjustment of the mirror plate 4 is dispensed with. However, the invention provides in a relatively simple manner a force-limited coupling between the pin 35 and the slot 36, by which it is meant that when an external force in excess of a given threshold level occurs, the pin 35 will leave the slot 36. That threshold level is chosen so that during normal operation, the frictional forces occurring will remain below that threshold level, but that on the other hand that threshold level can without excessive effort be overcome through the manual exertion of a pressure force on the mirror plate 4. The present invention provides several variants for realizing such force-limited coupling between the pin 35 and the slot 36. In a first variant, the wall portion 16 is slightly flexible, as a result of which that wall portion 16 will bent slightly outwards during the occurrence of an external force, causing the distance between that wall portion 16 and the disk 33 to increase. In a second variant, the axial position of the pin 35 relative to the worm wheel 32 is variable. Examples of this second variant are illustrated in Figs. 4A and 4B, each showing a longitudinal section of a worm wheel 32. In the exemplary embodiment illustrated in Fig. 4A, the worm wheel 32 is provided with an eccentrically positioned, axially directed bore 130, in which a pin 35 is arranged so as to be axially slidable. Arranged between the pin 35 and the bottom of the bore 130 is a resilient member 131 which presses the pin 35 outwards, i.e. leftwards in Fig. 4A. Preferably, the pin 35 is replaced by a ball. In the exemplary embodiment illustrated in Fig. 4B, the worm wheel 32 comprises a flexible -shaped 132, having one end thereof attached at an edge portion of the disk 33, while the other end of that L-shaped lip 132 defines the pin 35. An advantage of this last exemplary embodiment is that the combination of worm wheel 32, disk 33 and L-shaped lip 132 with pin 35 can be manufactured as a single, integral part. In order to facilitate the uncoupling of the pin 35 and the slot 36, the edge portions of the slot 36 are preferably slightly bevelled or rounded, and the pin 35 preferably has a convex or frusto-conical end. If the mirror plate 4 is indeed adjusted manually and the pin 35 has left the slot 36, the position of the pin 35 remains unchanged. In accordance with an important aspect of the present invention, the original position of the mirror plate 4 can subsequently be found back again in a simple manner, because when the mirror plate 4 and the pin 35 are manually pivoted back, the pin 35 and the slot 36 will meet each other again, with the pin 35 slipping into the slot 36. In accordance with another important aspect of the present invention, it is also possible to adjust the mirror plate 4 through operation of the motor 14 again after a manual adjustment of the mirror plate 4, because upon rotation of the worm wheel 32, the pin 35 will first move along the wall portion 16 until it meets the slot 36, involving the pin 35 slipping into the slot 36. It will be understood that the adjusting range of the mirror plate 4 will not have been affected by the earlier manual adjustment . In principle, the wall portion 16 may be a flat wall portion. However, the wall portion preferably has the shape of a portion of a spherical surface, with the center of that sphere substantially coinciding with the intersection S of the pivotal axes 6 and 7. In that case, the end face 34 of the disk 33 preferably has the shape of a portion of a spherical surface as well, with the center of that spherical surface likewise substantially coinciding with the intersection S of the pivotal axes 6 and 7, while the axis of rotation of the worm wheel 32 then preferably extends through this intersection S. This implies that the two axes of rotation of the two secondary worm wheels 32, 42 will intersect at the point S. Accordingly, the two axes of rotation of the two secondary worm wheels 32, 42 are in that case oblique relative to the respective axes of rotation of the respective secondary worms 31, 41, for which reason the secondary worm wheels 32, 42 then have an axial length greater than the diameter of the corresponding worms 31, 41. In the embodiments described hereinabove, the axis of rotation of the secondary worm wheel 32 is substantially perpendicular to the wall portion 16. In an alternative embodiment, the axis of rotation of the secondary worm wheel 32 is substantially perpendicular to the mirror support plate 5, and the disk 33 is in engagement with the wall portion 16 via its face 37, as illustrated in Fig. 5. The axis of rotation of the secondary worm wheel 32 is then substantially perpendicular to the axis of rotation of the corresponding secondary worm 31. In this case, the disk 33 has a greater axial length, while the diameter of the disk 33 is preferably a function of the axial position, adapted to the contour of the wall portion 16. In the example illustrated in Fig. 5, a projecting ridge 38, closed in itself, is formed on the face 37 of the disk 33, which ridge engages in a recessed portion or groove 36 of the wall portion 16. The function of that ridge 38 is comparable with the function of the pin 35 described first: upon rotation of the worm wheel 32, the axial position of that portion of the ridge 38 which faces the wall portion 16 changes, and the groove 36 of the wall portion 16 follows that changing axial position in a cyclic manner. Alternatively, the ridge 38 may be replaced by a groove closed in itself, with the wall portion 16 having a projecting pin instead of a slot 36, which pin engages in the groove mentioned. An advantage of such embodiment, not separately shown for simplicity's sake, is that in that case, a play-free contact between the disk 33 and the wall portion 16 can be guaranteed more easily at all angular positions of the worm wheel 32. An advantage of the use of a ridge or groove on the face 37 of the disk 33 is that it is possible to adjust the relation which describes the position of the wall portion 16 as function of the angle of rotation of the worm wheel 32, within certain limits. As will be understood by anyone skilled in the art, the position of the wall portion 16 of the embodiment illustrated in Figs. 3A-B can be described as a sinus of the angle of rotation of the worm wheel 32; this implies that at a constant rotational speed of the worm wheel 32, the displacement speed of the wall portion 16 can be described as a cosine of the angle of rotation of the worm wheel 32, i.e., adjacent the extreme positions the displacement speed is fairly low, and adjacent the central position the displacement speed is fairly high. 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Ω Φ Φ Hi CQ rt tr 3 3 3 tr Pi O 3 Ω r to 3 Φ μ j 3 rt o 3 3 ft ) Φ Φ LQ Pi rt μ- μ- tr S - 3 3 CQ rt tr tr rt 3 •<; rt μ- 3 rt rt μ- Ω ι ^ O ft) ft) ft ) ft ) Φ O CQ TJ Φ φ ≤ O tr ft ) 3 ft ) tr Hi > rr 3 D 3 H| CQ tr ti Φ Φ TJ i o CQ 3 ft ) Φ Φ φ μ- 3 tr μ- μ) ft ) μ- Φ rt 3 Hi rt μ- rt 3 X rt 3 Pi rt μ- rt Ω rt Φ 3 3 o X TJ ; IT & o tr Hi Q tr 3 O μ- μ- tr rt μ- Φ rt CQ tr ft ) Φ LQ Hi μ- Φ φ Hi - φ < Φ Φ Ω μ- rt rt S3T CQ Ω Φ O Hi Hi tr Φ P< μ- CQ ft) CO 3 μ- cn μ- Hh 0 3 Ω $. tr μ- ft) r Φ rt φ Hi Ω rt rt 3 ft ) ι & tr φ P. CQ tr tr Φ cn TJ O Ω tr ft ) o Ω CQ μ- ft ) cn CO tr TJ tr ft ) X φ φ Hi CQ Φ Hi μ rt (D 3 li ¬ tr TJ 3 LΠ rt Φ o Φ cn CQ μ- O Pi Φ Φ Ω Φφ Ω ft ) CQ μ- SD ft ) μ- rt i μ- ft ) SD Hi Hi i-i Φ CQ Hi μ- 3 φ i ft ) TJ 0 rt TJ CD O 3 r P μ- ft) 3 rt rt o Ω ft ) Ω Ω 3 3 Φ 3 tr cn HJ (D TJ CD 3 O pi Φ ft ) 3 tr TJ 3 Ω μ- rr O O TJ rt Hi ft ) Φ rt IT Hi *> 3 rt Φ rf^ μ- Hi 3 rt ft ) μ- Pi Ω LQ Φ Hj P r o O tr Hi o 3 o tr 0 I— ' Φ tr CQ t rt tr 3 SD 3 O tr Ω 3 rt μ- 3 3 Φ Pi Hi Φ 3 rt € Hi Φ TJ Φ Φ O ft ) ω H| Φ Hi Φ Ω IP μ- Φ tr TJ 3 n Hi tr Hi 3 rr 3 CD 0 μ- Φ Φ Hi ft 3 CQ 0 O CO 3 Hi ft ) Hi LQ oo ft ) Φ cn tr tr μ- tr P. T μ- Ω Ω uo Hi ti tr o 3 ft ) rt Hi μ- < μ- Φ μ- Φ 0 Φ H| 3 O rt to o Φ Φ cn 3 tr Φ (X O rt CQ μ- 3 tr 3 Ω tr 3 rt μ- μ- ft) 3 μ- P p LΠ 3 CQ φ 3 μ- Hi tr rt 3 ft ) tr ft ) Ω O Pi tr Φ μ- tr 3 LQ rt tr < Ω φ HJ - 3 3 φ μ- LQ Hi μ- < ft ) ft ) Φ Ω cn Ω Φ LQ tr 0 μ- Φ Φ < o μ- rt ft ) TJ IP r Ω Ω φ Hi I- i i μ- ,— ■ ft ) φ <! Pi ft ) 3 < tr tr o tr Pi O μ- rt O CD ft ) Φ σ, Hi Φ < O 3 Φ φ oo Φ SD rt HI ; Φ μ- rt 3 tr ft ) CQ tr t 0 X 3 Φ μ- Hi rt Φ rt φ Ω Hi tr Φ o tr Φ 3 TJ φ Hi Hi to CQ Hi μ- i Hi φ Hi o rt s: Hi tr rt Φ ft> ft) Φ rt Hi μ- μ- TJ TJ CQ CD o μ- Φ CQ Hi tr μ- ft ) tr rt Ω rt Φ 3 CQ 3 μ- CD ft X SD Hi rt P 3 rt Hi Φ Φ to X i ft ) O rt 3 3 φ CD φ 3 μ- tr μ- TJ cn S - o Φ Ω rt to μ- μ- rt rt μ- μ- £ μ- rt Ω P i 3 Φ 3 0 ι μ- Hi Pi O tr Hi CD ft ) S3- CQ ft O Hi tr rt tr o ≤ LQ LQ Hi X- ft ) < 3 o Φ Ω 3 Φ CD 3 rt Φ CQ TJ Φ 3 μ- rt rt rt Φ I-' Φ ft ) tr Pi CQ O φ TJ μ- Φ rt tr Φ cn PJ rt O tr cn cn μ- C CQQ Hi Hi ft ) Φ Φ ft ) 3 X rr ≤ μ- TJ 3 O tr Φ Ω ft ) rt LΠ tr Φ oo LΠ 0 o rt 0 0 Φ μ- Hi < Φ Φ Φ μ- Hi P, Hi Φ Hi φ Ω CD rt 3 tr Hi ft ) φ rt Φ ft ) TJ 3 Hi 3 ft ) Hi Φ to 3 Φ o ft ) Φ ft ) tr CQ μ- rt CQ ft ) Φ tr Φ 3 rt tr 3 3 O Ω & φ rt rt o o to rt P- 3 Ω Φ Φ CQ μ- Hi Φ 3 rt ft ) Φ Pi rt ft ) Hi Φ ft ) μ- Φ tr rt Hi Hi CQ Pi O rt Ω CQ rt cn φ Hi Ω μ- o CQ Hi 3 .3 μ- ft ) 3 Φ tr ft ) σ Φ 3 μ- TJ O TJ Φ CQ μ- Pi Φ O Hi Hi CQ O rt IP Q rt Pi Φ h- 1 ^ TJ cn & LQ Hi 3 ti Ω 3 Hi μ- Hi Φ 3 -J φ 3 tr i CD μ- TJ o SD 00 ft) S3- μ- P 0 O 0 CQ CQ rt o o Ω 3 Φ 3 Hi <! rr μ- 3 TJ ft ) H; rt 3 <J 3 μ- cn rt rt Ω 0 rt Hi Φ ιϋ 0 Si H| o O Φ O rt 3 O ft ) ft ) ^ ft ) CQ μ- Pi rt 3 tr <i 3 Φ μ- Hi rt Ω 3 Pi Hi CD rt Hi Hi Hi Φ Pi ft ) tr CD ! Φ ft ) cn Pi rt 3 3 ft ) rt ft ) tr i rt μ- Φ Φ μ- Ω Φ Hi 0 CQ μ- 3 -j ft ) tr P LQ rr rt 0 CQ ft ) μ- 3 o rt 0 pi * ; ft ) Hi Φ LQ Hi CQ rt ) μ > Φ CD tr Φ CQ o O Hj O LQ H| 3 i • Φ H £ ^ ft) rt 3 Hi Hi O 3 j 3 3 o Pi rt rt Ω μ- cn rt tr 3 Φ Hi ft ) o μ- tr n CQ O ft ) 3 3 Hi Hi LQ Φ rt 3 -> rt (X tr P rt secondary worms 31, 41, but are freely rotatable around those axis portions 63, 64. The helical springs 65, 68 are slightly elastically compressed relative to their rest conditions, i.e. a compressive stress condition prevails in the helical springs 65, 68, while their ends 67, 70 axially press against flanges 71, 72 respectively provided on the-- axes 63, 64. For simplicity's sake, Fig. 7A only shows the axis 63 of the first secondary worm 31 with the associated end 67 of the helical spring 65. Formed on the flange 71 is a cam 73 having a wedge-shaped outward appearance, as appears more clearly from the schematic perspective view of Fig. 7B, which shows the flange 71 viewed from a different direction. It will be understood by anyone skilled in that art that the end 67 of the helical spring 65 will take along that cam 73 formed on the worm 31 if the primary worm wheel 22 rotates in the direction as indicated by the arrow PI in Fig. 7A, and that the end 67 of the helical spring 65 will not be able to take along that cam 73 formed on the worm 31 but will be axially compressed by that cam 73, if the primary worm wheel 22 rotates in the opposite direction as indicated by the arrow P2 in Fig. 7A. Fig. 8A schematically shows a longitudinal section taken on the axis of rotation 57 of the primary worm wheel 22 of a third embodiment of the rotation-selective coupling 50, and Fig. 8B shows a cross section taken on the line B-B in Fig. 8A. The axis portion 63 of the first secondary worm 31 extends into the central opening 62 of the primary worm wheel 22. The axis portion 63 comprises a cam 81 having an radially directed side face 82, while the other side face of the cam 81 has a gradually decreasing diameter, so that the cam 81, in section, generally has the shape of the figure 6. Instead of one cam 81, the axis 63 may comprise several cams, displaced relative to each other in circumferential direction. Formed on the inner wall of the central opening 62 of the primary worm wheel 22 is a coupling finger 91, pointing UJ UJ to to P 1 P 1 o o o 0 Si μ- rt Hi 0 Hi Hi rt Hi 3 0 CD t s: TJ TJ Hi tr rt ^ Hi oo rt rt TJ Ω s- rt CD ft) μ- Hi φ tr φ TJ Φ Φ tr ft ) 0 Hi ? t μ- Hi to 0 Φ 0 μ- 0 P 1 tr 0 H{ Φ 0 tr μ-" 3 3 g Φ Hi Φ ft ) S- ft ) rt μ- μ- rt O rt 3 LQ rt ft ) O 3 Hi Φ μ- LQ : > ft 0 3 Φ HJ CO Φ rt rt CQ rt T tr < μ- ft ) rt rr . ft ) Hi ft Φ <! rt 3 LQ ft) tr 3 CD ft ) P ft ) 0 i-i H Φ tr H| P- 3 tt ft ) rr 0 ft ) μ- Hi μ- tr Φ P Φ CQ rt Ω φ rt 3 μ- μ- Φ φ φ rt Φ 0 r - oo Φ ti ft Ω Pi ft ) $, 3 π rt H rt 3 μ- H • rt 3 φ > i Hh tr Φ ^ CQ 3 φ d CD 3 tr tr φ tr 3 ≤ O ft ) Hi ft ) 3 Ω 0 3 rt ft ) LQ CQ CD 3 Φ Φ Pi tr μ- rt - Φ Φ rt Φ Φ ^ μ- Ω ft ) rt ft ) Φ 3 tr Hi μ- CQ TJ TJ Hi Φ iQ μ- £ ft ) μ- Pi o 0 Φ HJ rr Hi ft ft Φ rt rt Φ rr CQ 3 - Hi ft ) Φ ft ) CD s: • 3 ft ) 1— ' ft ) 3 Ω £ rt s: TJ - 1 Hi tr H 3 Φ Pi 0 rt 0 tr O 0 μ- Hi tr φ P- TJ Hi 0 3 O 0 μ- tr μ- Φ Z μ- 1 0 ft) Hi 0 Hi φ rt CQ μ- $, 3 <! CQ Ω rt Hi 00 rt Pi 3 P rt 3 3 Φ rt 3 to ft) φ ft ) 3 rt ft μ- 3 ^ ft) μ- CQ tr IP ft ) O ^ o tr μ- t tr CD LQ S3- TJ Hi tr μ- to X 0 tr 3 ft ) CQ ft SD μ- 3 g φ Φ 3 3 3 g • Φ rt Φ r 3 . 1— ' μ- Hi rt P ft ) Ω Ω S3- tr Hj TJ . Hi Φ rt tr i 0 ft) tr rt tr tr μ- tr μ- CQ IP tr SD tr rt ^ Ω tr Φ 0 Pi Φ 3 ft ) Φ 3 Hi 0 tr ft ) Φ 3 φ 3 Φ M O P 1 P ft ) tr μ- 0 Φ <! μ- Φ > ft ) LQ μ- CQ Φ •<; TJ ft ) rt μ- I < cn 3 Hi φ μ- ft 0 rt iQ Hi 3 TJ Φ Φ CQ 3 CQ Φ 3 φ TJ rt rt H ≤ 3 Ω Φ to CQ •• ft> 3 tr CD Pi ft ) Hi rt 0 IP Ω 0 ≤ o tr rt Φ 0 Hi 3 μ- i-i ft rt μ- CQ Φ • μ- rt Φ a rt O ft) rt <! 0 0 Hi 0 CQ Φ Ω tr Ω Hi μ- & Hj ft ) O Φ tr ft ) 3 μ- 3 μ- CQ Φ 0 tr i tr Φ H CQ 3 H{ μ- ft ) Φ rt 3 3 Φ Ω H ft) Φ 3 P 3 3 tr VO LQ Ω Φ CO Pi φ TJ < Φ Hi l-d 3 g rt Ω g μ- LQ Hi 3 & μ- Φ Q o 3 Ω μ- i-i Hi ft) rt 3 ft ) o Φ SD Ω 0 UJ Φ CD 3 Ω rt Ω HJ p. rt 1 rt rt Hf g φ 0 3 0 rt tr 3 Hi Hi s; 3 oo 0 3 P 1 Hi rt Hi O tr 0 Φ Ω φ rt o 0 Hi μ- Φ Hi i rt rt tr φ φ ^ Φ tr SOi P 1 3 O Φ 3 φ Hi 3 ft ) Ω ≤ 0 ft ) μ- TJ 3 0 3 ft) tr Φ rt Φ μ- oo TJ ft ) μ- LO O Hi TJ ft 3 ft ft ) 3 rt $, 3 rt rt Hi Ω LQ Φ Hi Hi : > Ω Φ Hi P 1 Hi CO Hi μ 1 fX Φ TJ O Hi μ- ft ) t-3 tr μ- <! μ- φ Φ Φ Hi 3 μ- μ- 0 O Φ - 0 μ- 3 P- Hi 3 ft ) tr 0 Hi TJ tr Φ 3 Φ o μ- 0 μ. Ω H{ 3 Ω Hi 3 μ- rt ≤ tr rt 3 μ- φ h- 1 Φ 3 Φ ft ) Φ LQ 3 3 CO g ft ) 0 rt 3 CQ ft ) 3 TJ to rt μ- 3 LQ 3 tr tr " μ- LQ 3 3 μ- Hi CQ TJ CO rt - o 3 Hi J > 1 rt - 1 to μ- Hl Φ sx φ μ- ft> ft ) Ω 0 P 3 μ- rt Φ Hi • μ- TJ Hi Pi 0 Pi ^ μ- 0 Pi Hi μ- Ω ft ) Hi Hi O TJ 3 Φ 0 rt Hi φ rt Hi Φ P 1 3 μ- 3 r μ- Ω TJ S3- 3 μ- •<; 3 φ ft ) tr ft ) rt μ> ^ CQ > 3 tr Φ ft) tr φ μ- 3 ft ) - IP co tr 0 3 SD Hi ^ 3 TJ 3 3 φ Φ to μ- Φ Φ Hi μ- CQ Φ g <! o CO ft ) Φ 3 LQ rt μ- c 0 P- LQ ≤ h- μ- P Hi ιp 3 TJ ft) Φ 3 CQ 6* φ 0 ft Hi μ- CQ Φ Φ 3 μ- 3 Hi φ 0 μ- 3 Ω μ- Ω ft ) 3 rt Hi Hi Ω Hi φ Φ rt o 3 ≤ tr μ- 3 TJ rt P S- ft) h- 1 φ Φ Hi Hi 3 LQ O 0 Hi O 3 Hi ft) φ o Hi X 3 tr Pi μ- μ- Φ 3 μ- Hi tr Hi Ω CQ 3 LQ Hi 3 φ 3 Φ μ- Ω 3 Φ TJ tr μ- μ- ft ) 3 IP ft ) 3 μ- φ LD tr CD ft ~ cn TJ Ω 3 CQ 3 rt φ CQ Φ μ j HS g X Φ TJ Φ g *< rt r μ- ≤ Hi to TJ h- 1 rt Φ rt < μ- X rt 3 Φ Pi Φ μ- 3 i-i P Ω μ- ft ) s; ft ) μ- 0 Pi tr μ- μ- μ- μ- Ω tr Ω Φ Ω TJ Hi CD - 3 CD rt tr μ- CQ 0 Ω H| 0 ≤ rt 0 ? 3 μ- Φ 3 O <<" 3 0 rt Φ 3 ft ) h- 1 3 μ- Φ rt φ 3 f ) g CO μ- μ- ft ) ≤ T 3 ft ) ^ Hi μ- S3- Hi φ co Φ LQ Hi 0 LQ 3 Φ φ rt ft ) Ω <! t J ft 3 Φ 3 φ TJ Φ rt Ω ft) μ- μ- rt φ 3 " CQ CQ 3 Hi tr ft ) Φ s: P ft) P ft Hi Ξ 0 H 0 Φ 3 μ- - (X 0 TJ 3 ^ μ- Hi 0 ω ft ) ≤ ft) to S3" Hi μ- tr ft ) <! 3 Φ 0 H{ < rt Pi Ω ft ) Hi P 1 3 H S3- 0 μ- Ω to <£> Φ Φ 3 μ- rt φ ^ 3 Hi rr μ- 0 μ- tr Φ £ tr tr tr g O Hi Φ 3 3 φ LQ Ω i-i μ- 0 0 3" 3 Pi Hi ft ) H{ 0 μ- 1 *< tr rt 0 Φ IP i 3 ~ TJ ft ) Φ tr SD Q s % ft) Hi ft ) φ 3 rt rr CD p. Ω φ ≤ 3 £ P- 1 rt ft) Hj rt Hi TJ μ- μ- 3 rt 3 Ω 3 rt 3 o rt tr rt tr rt tr H{ ^ rt μ- μ- 3 Ω ft ) g rt rt Φ ft ) CQ 0 3 3 tr Φ φ T to tr ft ) Φ tr 3 < v > ft ) Φ Hi Φ tr tr μ- μ- ■ 0 S. TJ ft ) Φ Φ ≤ to Φ rt μ- 1 tr Φ ft) Φ μ> tr 3 rt 3 μ- CQ μ- ft ) μ- Pi tr 1— ' 3 μ- ft ) ft) Φ Hi Φ rt rt Ω CQ ^ J Φ Φ 3 ft ) μ- 1 tr μ- Ω ft ) rt ^ rt μ- CD Hi μ> tr tr TJ tr Φ Φ Hi to 3 ft ) Hi μ- 0 CQ ft ) UJ 0 ft ) μ- < Hi Hi to φ 3 rt < SD h- 1 Hi CQ 3 0 tr Φ 3 LQ ft ) φ point by a ball joint 18, acting as common pivot point for the horizontal pivotal movement and the vertical pivotal movement . It will be readily understood by anyone skilled in the art that it is possible to change or modify the embodiment shown of the apparatus according to the invention without departing from the inventive concept or the protective scope as defined in the claims. For instance, in respect of the embodiment illustrated in Figs. 8A-B, it is possible that the helical spring 65 does not engage an outer surface of an axis portion 63, but an inner surface of an axial bore formed in the worm wheel 31. It is also possible that the helically wound helical springs 65, 68 are fixedly mounted on the axis portions 63; 64 of the secondary worms 31; 41 and are coupled with slip or via a ratchet coupling to the primary worm wheel 22. Further, with respect to the embodiment illustrated in Figs. 8A-B, it is for instance possible that the inner wall of the central opening 62 of the primary worm wheel 22 is provided with asymmetrical cams, while the axis portion 63, 64 extending into that central opening 62 is provided with flexible coupling fingers. In the foregoing, it is described that the bottom portion 12 of the actuator housing 11 is attached to the mirror housing 2, and that the cover portion 13 is attached to the mirror support plate 5. However, it will be understood that the actuator housing 11 may also be mounted the other way round. In the foregoing, the particular advantages of the present invention are described in connection with an actuator which comprises only one motor and which is intended for effecting four different movements. An important aspect of the present invention is a coupling member capable of converting a rotational movement into a LΠ

Claims: CLAIMS 1. A one-motor actuator (10), comprising: a first reduction step (20) formed by a primary worm (21) and a primary worm wheel (22) ; a second reduction step (30) formed by a first secondary worm (31) and a first secondary worm wheel (32) ; a third reduction step (40) formed by a second secondary worm (41) and a second secondary worm wheel (42); a rotation-selective coupling (50) coupled between on one side the primary worm wheel (22) and on the other side the first secondary worm (31) and the second secondary worm (41) ; an actuator housing (11) , comprising a housing bottom (12) and a housing cover (13) capable of pivoting relative to the housing bottom (11) about two different pivotal axes (6 and 7), said reduction steps (20; 30; 40) being bearing- mounted relative to said housing bottom (12) ; wherein each of said secondary worm wheels (32; 42) is detachably coupled to mutually different portions of said housing cover (13) for converting a rotation of a worm wheel (32; 42) into a cyclic pivotal movement of said housing cover (13) about a respective one of said pivotal axes (6 ; 7) . 2. An actuator according to claim 1, wherein a worm wheel (32) has an end face (34) provided with an axially directed, but eccentrically positioned pin (35) engaging in a recess or slot (36) formed in a wall portion (16) of the housing cover (13) . 3. An actuator according to claim 2, wherein said wall portion (16) is of slightly flexible design, so that during the occurrence of an external force, said pin (35) can leave said slot (36) by bending said wall portion (16) . 4. An actuator according to claim 2, wherein said pin (35) is axially displaceable relative to said worm wheel (32) . 5. An actuator according to claim 4, wherein said pin (35) is accommodated in a substantially axially directed bore (130) in said worm wheel (32) , while further disposed in said bore (130) is a resilient member (131) . 6. An actuator according to claim 4, wherein said pin (35) is defined by a substantially L-shaped lip (132) which is bendably and/or pivotally attached to said worm wheel (32) . 7. An actuator according to claim 6, wherein said L-shaped lip (132) and said worm wheel (32) are integrally formed as one single member. 8. An actuator according to claim 1, wherein a worm wheel (32) comprises a disk (33) which is coaxially formed thereon and which has its face (37) provided with a ridge (38), closed in itself, engaging in a recess or slot (36) formed in a wall portion (16) of the housing cover (13) . 9. An actuator according to claim 8, wherein said wall portion (16) is of slightly flexible design, so that, during the occurrence of an external force, said ridge (38) can leave said slot (36) by bending said wall portion (16) . 10. An actuator according to claim 8 or 9, wherein the ridge (38) is replaced by a groove and the slot (36) is replaced by a projection. 11. A worm wheel (32) provided, at its end face (34), with an axially directed, but eccentrically positioned pin (35) . 12. A worm wheel according to claim 11, wherein said pin (35) is axially displaceable relative to said worm wheel (32) . 13. A worm wheel according to claim 12, wherein said pin (35) is accommodated in a substantially axially directed bore (130) in said worm wheel (32) , while further disposed in said bore (130) is a resilient member (131) . 14. A worm wheel according to claim 12, wherein said pin (35) is defined by a substantially L-shaped lip (132) which is bendably and/or pivotally attached to said worm wheel (32) , wherein said L-shaped lip (132) and said worm wheel (32) are preferably integrally formed as a single member. 15. An actuator according to any one of claims 1-10, wherein said rotation-selective coupling (50) comprises a first helically wound helical spring (65) which is on one side rigidly attached to the primary worm wheel (22) and on the other side coupled to the first secondary worm (31) , and a second helically wound helical spring (68) which is on one side rigidly attached to the primary worm wheel (22) and on the other side coupled to the second secondary worm (41) . 16. An actuator according to claim 15, wherein the coupling between a helical spring (65; 68) and a secondary worm (31; 41) is designed as a wrap spring coupling. 17. An actuator according to claim 15, wherein each secondary worm (31; 41) is provided with a one-sidedly acting cam (73) cooperating with the end of the relevant helical spring (65; 68). 18. An actuator according to any one of claims 1-10, wherein said rotation-selective coupling (50) is defined in that each secondary worm (31; 41) has an axis portion (63; 64) extending into an axial opening (62) in the primary worm wheel (22), wherein projecting cams or fingers (81; 91) are provided on the outer surface of said axis portions (63; 64) and on the inner surface of said opening (62), which cooperate for transmitting a rotation in only one direction. 19. An actuator (10), comprising at least one motor (14) and a reduction transmission mechanism (20, 30) driven by said motor (14) , the final link of said mechanism comprising a worm wheel (32) according to any one of claims 11-14. 20. A wing mirror (1) for a vehicle, comprising a mirror housing (2) and a mirror plate (4) pivotable relative to said mirror housing (2) , and an actuator (10) according to any one of claims 1-10 or 15-19.

Inventors: BROUWER STEFAN FRITZ, BROUWER, STEFAN, FRITZ
Applicants: BROUWER STEFAN FRITZ, IKU HOLDING MONTFOORT BV, BROUWER, STEFAN, FRITZ, IKU HOLDING MONTFOORT B.V.
Application year: 1998
Main classification: B60R1
IPC codes: B60R1, F16H1