This invention relates to a power transmitting apparatus for use in a vehicle and, more particularly, to an apparatus capable of transmitting power from a motor to a plurality of operating shafts and specifically suitable for application to an apparatus for adjusting the height or angle of a seat for use in a vehicle.
Various types of power transmitting apparatus have been heretofore proposed.
In a power transmitting apparatus which moves a predetermined object to a predetermined position on an X-Y table by transmitting power to two shafts perpendicular to each other, independent motors which are adapted for operations with respect to X- and Y-axes are used to move the object.
For adjustment of a seat for use in a vehicle, an apparatus has been proposed which is capable of adjusting the reclining angle of the seat, moving the seat toward the front or rear of the vehicle, and moving the front end of the seat in the vertical direction all in electrically driving manners.
To provide such three moving means in the conventional type of apparatus for moving the vehicle seat, however, three motors each capable of rotating in normal and reverse directions are used to adjust the seat by moving it in a predetermined direction by a predetermined angle or to a predetermined height.
For a rear-view mirror attached to a door of a latest type of vehicle, an apparatus for adjusting the angle of the rear-view mirror by using a motor is provided. It is necessary for this type of apparatus to adjust angles of the rear-view mirror in the vertical and horizontal directions. A pair of apparatuses of this type are used to move two rear-view mirrors which are disposed on the right- and left-hand sides of the driver's seat. Therefore, four motors each capable of rotating in normal and reverse directions and adpated for adjusting the mirrors are needed for one vehicle.
Various power transmitting apparatuses heretofore used thus need a number of motors that corresponds to a predetermined number of operations which need to be performed, resulting in increases in the size and weight of the apparatus as well as the probability of malfunctions.
In a conventional apparatus designed in consideration of this problem, a plurality of operating shafts are selectively rotated by using only one motor.
An example of this type of apparatus is constructed such that a plurality of gears are successively connected to a gear which is fixed to an output shaft of a motor; an operating shaft is connected to each of the plurality of gears; and a clutch is interposed between each of corresponding pairs of the gears and operating shafts. In this apparatus, one of the operating shafts to be rotated is selected by operating the clutches.
This arrangement makes it possible to perform desired operation by using only one motor, but it uses an increased number of clutches and increases the size and weight of the apparatus as well as the probability of malfunctions. Also there is a problem of power loss between the plurality of gears.
In another example, a motor or an intermediate gear which is connected to an output shaft of the motor is moved by manual operation so as to select one of the plurality of operating shafts and enable the power to be transmitted.
However, such a means necessitates the troublesome operation of manually selecting the operating shafts, and therefore increases the possibility of selection errors. Moreover, the use of the intermediate gear creates a direction in which the motor or the output shaft of the motor moves more difficult, depending upon the direction in which the motor rotates, or it causes power loss.