TILTING ANGLE CONTROL DEVICE FOR AUTOMOBILE OUTSIDE REARVIEW MIRROR

Abstract: An automatically or manually operated tilting angle control device for automobile outside rearview mirror is disclosed. The device causes neither operational noise nor malfunction of power transmission gear and thereby achieving smooth power transmission of the gear and providing reliable rear view for the driver. A pair of cylindrical reduction gears (26) are vertically placed in the mirror housing (18) such that the gears (26) are spaced apart from the pivot shaft (P) by a distance in a transverse axis and in a longitudinal axis of the mirror housing (18). The top of each reduction gear (26) has a tension part (T) provided with a tension nut (40). An outer threaded tilting shaft (36) jointed to a movable holder engages with the tension nut (40) of the reduction gear (26). The tilting shaft (36) is lifted or lowered by the rotating force of the reduction gear (26), thus to longitudinally and transversely tilt the mirror mount.

Description: TILTING ANGLE CONTROL DEVICE FOR AUTOMOBILE OUTSIDE REARVIEW MIRROR BACKGROUND OF THE INVENTION Field of the Invention The present invention relates in general to a motor operated device for control of tilting angle of automobile outside rearview mirror and, more particularly, to a structural improvement in such a tilting angle control device for causing neither operational noise nor malfunction of power transmission gear due to overload of the gear and thereby achieving smooth power transmission and desired solidity of the transmission gear and providing reliable rear view for the driver. Description of the Prior Art As well known to those skilled in the art, opposed rearview mirrors are mounted to opposed sides of an automobile body in order for providing rear views for the driver in steering the automobile and thereby letting the driver safely steer the automobile. As the desired tilting angles of the rearview mirrors differ from each other in accordance with intrinsic views of the drivers, the rearview mirrors should be tilted by tilting angle control devices and meet with the intrinsic views of the drivers. In an effort to achieve handling facility along with simple and smooth tilting motion of the mirrors, motor operated devices have been recently wide used in control of the tilting angles of the mirrors. Japanese U.M. Laid-open Publication No. Heisei. 1- 82951 discloses a motor operated device of the remote control type, which device is concerned with this invention, for controlling the rearview mirror tilting angle. This Japanese control device uses a reduction gear mechanism in order for adjusting the tilting angle of the rearview mirror. That is, the rotating force of a drive motor of the above control device is transmitted to an outer threaded vertical shaft, thus to tilt the rearview mirror as desired. The outer threaded shaft engages with an inner threaded member of a reciprocating arm pivoted to a mirror mount, thus to let the arm vertically reciprocate within a predetermined range and to tilt the mirror about a center pivot shaft when the outer threaded shaft is rotated by the rotating force of the drive motor. In this case, the bottom of the outer threaded shaft is seated on a flexible plate so that smooth tilting motion of the outer threaded shaft can be achieved by the flexible plate. In addition, Japanese U.M. Laid-open Publication No. Sho. 58-32038 discloses another type of rearview mirror tilting angle control device. In this control device, the rotating force of a drive motor is transmitted to a rotor through a reduction gear mechanism in the similar manner to that of the above-described Japanese device. The rotor engages with a nut of a retractable arm with interposition of a spring, thus to let the arm vertically reciprocate within a predetermined range and to tilt the mirror about a center pivot shaft when the rotor is transmitted with the rotating force of the drive motor. There have been also proposed several types of devices for control the rearview mirror tilting angle, which devices are partially changed in constructions of their power transmission mechanisms in order for allowing smooth tilting motions of the mechanisms in the similar manner to those described for the above Japanese devices. However, the typical control devices including the above two Japanese control devices fail in inducing smooth tilting motions of the mirror mounts from rectilinear motions of the power transmission mechanisms. Therefore, the above control devices have a problem that they cause operational noise and malfunction of the power transmission mechanisms. SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a tilting angle control device for automobile outside rearview mirror in which the above problems can be overcome and which is easily assembled due to a simple construction including a few elements and causes neither operational noise nor malfunction of power transmission gear due to overload and thereby achieving smooth power transmission of the gear and providing reliable rear view for driver. It is another object of the present invention to provide a tilting angle control device for automobile outside rearview mirror which is automatically or manually operated. In order to accomplish the above object, the present invention provides a tilting angle control device for automobile outside rearview mirror comprising: a mirror mounted to a mirror mount, the mirror mount being pivoted to a pivot shaft such that the mirror mount is longitudinally transversely tilted about the pivot shaft; a mirror housing mounted to a base plate of an automobile body and having a top case and a bottom case, wherein the improvement comprises: a pair of cylindrical reduction gears placed in the mirror housing such that they are spaced apart from the pivot shaft by a distance in a transverse axis and in a longitudinal axis of the mirror housing, each of the reduction gears being vertically placed and rotatably retained between the top and bottom cases by contacting the top of each reduction gear with a guide surface of an associated fixing ring of the top case and by keeping the bottom of each reduction gear in a stepped annular seat of an associated support cup of the bottom case, the top of each reduction gear having a tension part provided with a tension nut; and a pair of outer threaded tilting shafts jointed to a movable holder and vertically placed in the reduction gears respectively, the threads of each tilting shaft engaging with the tension nut of an associated reduction gear, whereby the tilting shafts are lifted or lowered by rotating force of the reduction gears, thus to longitudinally transversely tilt the mirror mount. BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: Fig. 1 is a partially sectioned view of a rearview mirror assembly provided with a tilting angle control device of the present invention; Fig. 2 is an enlarged and partially broken perspective view of the control device of Fig. 1; Fig. 3 is a partially broken plan view of the control device of Fig. 1; Fig. 4 is a sectional view of the control device taken along the section line A-A of Fig. 3; and Fig. 5 is a schematic view showing a tilting motion of an outer threaded shaft relative to a tension nut in the control device of the invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to the drawings. Figs. 1 to 5, there is shown a rearview mirror tilting angle control device in accordance with a preferred embodiment of the invention. As shown in Fig. 1, a rearview mirror assembly having the control device of this invention includes a mirror 10, which mirror 10 is a plate mirror, a concave mirror or a convex mirror and mounted to a mirror mount 12. The bottom center of the mirror mount 12 with the mirror 10 is pivoted to a center pivot shaft P such that the mount 12 can be longitudinally and transversely tilted about the center pivot shaft P. The mirror assembly also includes a mirror housing 18 mounted to a base plate 20, which plate 20 in turn will be mounted to a side of the automobile body (not shown). The mirror housing 18 includes two cases, that is a top case 14 and a bottom case 16, and a pair of outer threaded tilting shafts 36 vertically retained between the two cases 14 and 16. The vertically placed tilting shafts 36 which are elements of the control device of this invention are spaced apart from the center pivot shaft P by a predetermined distance in the transverse axis Y and in the longitudinal axis X of the mirror housing 18 respectively. In the mirror assembly, the transverse axis is represented by the Y-axis, while the longitudinal axis is represented by the X-axis as shown in Fig. 3. A top fixing ring 22 is fitted in the top case 14 such that the ring 22 surrounds the top section of the tilting shaft 36. The bottom of the ring 22 is provided with a rounded guide surface 24. The control device also includes a cylindrical reduction gear 26 which surrounds the tilting shaft 36 and whose top is rolled inwardly, thus to form a tension part T provided with a tension nut 40, which tension nut 40 engages with the threads 38 of the shaft 36. The rounded top of the reduction gear 26 comes into close contact with the guide surface 24 of the ring 22. The annular bottom of the reduction gear 26 is sized such that it is received in a stepped annular seat 30 of a support cup 28 of the bottom case 16. A ball seat 34 is provided on the bottom of a movable holder 42. The ball seat 34 receives a ball of the tilting shaft 36 so that the movable holder 42 is pivoted to the shaft 36 through the ball joint. As the outer threaded tilting shaft 36 engages with the tension nut 40 of the reduction gear 26 retained between the top and bottom cases 14 and 16, the ball seat 34 of the holder 42 is lifted or lowered in accordance with vertical reciprocation of the shaft 36 relative to the reduction gear 26. The reduction gear 26 can not vertically move but is simply rotated by the rotating force of the drive motor. In the drawings, the reference numeral 44 denotes the drive motor, 46 denotes an output worm of the drive motor, 48 denotes a worm wheel circumferentially formed on the reduction gear 26 and gearing into the worm 46, and β and β' denote left and right tilting angles of the shaft 36 respectively. In operation of the above tilting angle control device, the rotating force of the reversible motor 44 is transmitted to the reduction gear 26 due to engagement between the output worm 46 and the worm wheel 48 of the reduction gear 26, which reduction gear 26 is supported at its opposed ends by the top fixing ring 22 of the top case 14 and the stepped annular seat 30 of the bottom case 16. As the semi-hollow ring type tension nut 40 provided in the top of the reduction gear 26 gears into the outer threaded tilting shaft 36 as described above, the shaft 36 vertically rectilinearly reciprocates by rotation of the reduction gear 26. When the movable pivot shaft c of Fig. 4 is moved between the positions "a" and "b", the outer threaded shaft 36 is tilted relative to the tension nut 40 of the gear 26 at the tilting angles β and β' as shown in Fig. 5. Even when the shaft 36 is tilted as described above, the rotating force of the drive motor 44 can be reliably transmitted to the shaft 36 through the tension nut 40 of the reduction gear 26. In the control device of the invention, the above- described operation is orderly carried out using the rotating force of the two drive motors of Fig. 3, thus to tilt the rearview mirrors 10. Therefore, the rearview mirrors are transversely or longitudinally tilted by the control device of the invention. On the other hand, the control device of the invention may be manually controlled. When manually tilting the mirror 10, the mirror 10 is manually pushed at a portion in the transverse or longitudinal direction so that the manual pushing force is transmitted to the engagement portion between the shaft 36 and the reduction gear 26. When the pushing force is larger than the frictional force between the shaft 36 and the tension nut 40, the shaft 36 moves relative to the nut 40 and vertical reciprocates so that the mirror 10 is tilted about the center pivot shaft at a tilting angle α or α* . Therefore, the control device of the invention may be automatically controlled through the remote-control operation or manually controlled when tilting the mirror 10. As described above, the tilting angle control device of the invention can automatically tilt the rearview mirror through the remote-control operation or manually tilt the mirror, thus to provide reliable rear view for driver and to let the driver safely steer the automobile. In addition, the control device is easily assembled due to a simple construction including a few elements and causes neither operational noise nor malfunction of the power transmission gear and thereby achieving smooth power transmission during the mirror tilting operation.

Claims: WHAT IS CLAIMED IS: 1. A tilting angle control device for automobile outside rearview mirror comprising: a mirror mounted to a mirror mount, said mirror mount being pivoted to a pivot shaft such that the mirror mount is longitudinally transversely tilted about the pivot shaft; and a mirror housing mounted to a base plate of an automobile body and having a top case and a bottom case, wherein the improvement comprises: a pair of cylindrical reduction gears placed in said mirror housing such that they are spaced apart from said pivot shaft by a distance in a transverse axis and in a longitudinal axis of the mirror housing, each of said reduction gears being vertically placed and rotatably retained between said top and bottom cases by contacting the top of each reduction gear with a guide surface of an associated fixing ring of said top case and by keeping the bottom of each reduction gear in a stepped annular seat of an associated support cup of said bottom case, the top of each reduction gear having a tension nut; and a pair of outer threaded tilting shafts jointed to a movable holder and vertically placed in the reduction gears respectively, the threads of each tilting shaft engaging with the tension nut of an associated reduction gear, whereby said tilting shafts are lifted or lowered by rotating force of the reduction gears, thus to longitudinally transversely tilt the mirror mount.

Inventors: LEE GUN HWAN, LEE, GUN, HWAN
Applicants: LEE GUN HWAN, POONG JEONG IND CO LTD, LEE, GUN, HWAN, POONG JEONG IND. CO., LTD.
Application year: 1995
Main classification: B60R1
IPC codes: B60R1