Power door-lock actuator with pivoting rocker and connecting gears

A power door-lock actuator has a housing adjacent the lock, a reversible electric motor in the housing having an output shaft extending along a motor axis, and an input gear fixed on the output shaft and rotatable thereby about the motor axis. A threaded spindle extending in the housing along a spindle axis adjacent the motor axis carries an output gear and a nut threaded on the spindle is movable along the spindle axis on rotation of the spindle between a pair of axially offset positions. A link connected between the nut and the lock can move the lock between its locked and unlocked positions on displacement of the nut between its end positions. A manual actuator, for instance an inside door-lock button, is coupled to the nut for manually displacing the nut between its end positions. A rocker pivotal about the shaft axia at the input gear carries a pair of connecting gears flanking and meshing with the input gear. This rocker is pivotal between angled positions in each of which a respective one of the connecting gears meshes with the output gear and through a central position with neither of the connecting gears meshing with the output gear. A spring urges the rocker into the central position so that torque transmitted to the rocker on rotation of the input gear pivots the rocker depending on input-gear rotation direction into one of its angled positions to couple the input gear to the output gear.

FIELD OF THE INVENTION 
The present invention relates to an actuator for a power door lock. More 
particularly this invention concerns such an actuator used in a 
motor-vehicle door lock and having a manual override. 
BACKGROUND OF THE INVENTION 
As described in commonly owned U.S. Pat. No. 5,056,343 issued Oct. 15, 1991 
a motor-vehicle latch has an actuating lever displaceable between a 
position in which a respective door of the vehicle is locked and a 
position in which the respective door is unlocked. A locking knob 
connected to the lever is accessible from inside the vehicle to displace 
the lever between its positions. The actuator has a housing mounted 
directly on the door latch and formed with at least one longitudinally 
directed abutment face, a motor in the housing, a nut longitudinally 
displaceable in the housing by the motor between unlocked, locked, and 
antitheft positions, and a slide in the housing movable by the nut between 
locked and unlocked positions and formed with a recess receiving a portion 
projecting from the lever. At least one flexible arm extends 
longitudinally from the slide and has a head formed with a face directed 
longitudinally opposite the abutment face of the housing. These faces 
longitudinally confront but are out of longitudinal line with each other 
in the locked positions of the slide and nut. An actuating formation on 
the nut is engageable with the arm for laterally elastically deflecting 
the arm on displacement of the nut from the respective locked to the 
antitheft position. Thus the faces are longitudinally aligned and prevent 
displacement of the slide into the unlocked position with the nut in th 
antitheft position. 
Such a lock has a manual override so that in the locked and unlocked 
positions the slide can be shifted manually. While this system is fairly 
effective, manually overriding the power actuation upsets the timing of 
the assembly. Thus once, for instance, a door that has been locked by the 
power actuator has been unlocked manually, it is necessary to cycle the 
power actuator through the locked position to set the parts back in the 
right positions relative to each other. 
OBJECTS OF THE INVENTION 
It is therefore object of the present invention to provide an improved 
vehicle power-lock actuator. 
Another object is the provision of such an improved vehicle power-lock 
actuator which overcomes the above-given disadvantages, that is which does 
not need to be reset after manual actuation. 
SUMMARY OF THE INVENTION 
The instant invention is used in combination with a door lock movable 
between an locked position and an unlocked position. It is an actuator 
having a housing adjacent the lock, a reversible electric motor in the 
housing having an output shaft extending along a motor axis, and an input 
gear fixed on the output shaft and rotatable thereby about the motor axis. 
A threaded spindle extending in the housing along a spindle axis adjacent 
the motor axis carries an output gear and a nut threaded on the spindle is 
movable along the spindle axis on rotation of the spindle between a pair 
of axially offset positions. A link connected between the nut and the lock 
can move the lock between its locked and unlocked positions on 
displacement of the nut between its end positions. A manual actuator, for 
instance an inside door-lock button, is coupled to the nut for manually 
displacing the nut between its end positions. A rocker pivotal about the 
shaft axis at the input gear carries a pair of connecting gears centered 
on axes parallel to the shaft axis and both flanking and meshing with the 
input gear. This rocker is pivotal between one angled position with one of 
the connecting gears meshing with the output gear and another angled 
position with the other of the connecting gears meshing with the output 
gear and through a central position with neither of the connecting gears 
meshing with the output gear. A spring urges the rocker into the central 
position so that torque transmitted to the rocker on rotation of the input 
gear pivots the rocker depending on input-gear rotation direction into one 
of its angled positions to couple the input gear to the output gear. 
Thus with this system operation of the motor automatically couples one of 
the connecting gears to the output gear, but when the motor is not 
energized and rotating the input gear neither of these connecting gears is 
in mesh with the output gear, and the input gear never meshes with the 
output gear. Thus the manual-actuation element can shift the nut but the 
motor can take over displacing it in any position, without having to 
resynchronize the positions of the parts. 
According to another feature of the invention the rocker is of U-section 
and has a pair of longitudinally extending sides through which the output 
shaft extends and flanking the input and connecting gears. Furthermore the 
motor axis and spindle axis are parallel and define a plane and the spring 
is a compression spring braced between the rocker and the housing and 
generally centered on the plane. 
The link of this invention is a lever pivoted on the housing and having one 
end connected to the nut.

SPECIFIC DESCRIPTION 
As seen in the drawing a power actuator has a housing 8 in which is mounted 
a motor 1 having an output shaft 2 extending along a shaft axis 2A. The 
motor 1 is a reversible electric motor operated by a standard central lock 
system 16 and serving to shift a door lock shown schematically at 15 
between a locked and unlocked position and, if desired, into an 
unillustrated antitheft position. 
The shaft 2 carries a small-diameter input gear or pinion 3. An output gear 
4 that is spaced from and out of mesh with this gear 3 is carried on a 
threaded spindle 5 rotatable in the housing 8 about an axis 5A parallel to 
the axis 2A and carrying a nut 6 constrained against rotating and coupled 
to the upper end of an operating link or lever 7. The door lock 15 is 
coupled to an unillustrated shaft fitted to the center of the lever 7 at 
its pivot axis 7A and a manual-actuation button or element 14 is coupled 
to the lower end of this lever 7. Movement of the nut 6 between its end 
positions, one of which is shown in FIG. 1 in solid lines and the other in 
dot-dash lines, pivots the lever 7 and moves the lock 15 between its 
locked and unlocked positions. Similarly manual actuation of the lever 7 
by the element 14 can lock and unlock the door controlled by the lock 15. 
According to the invention a rocker 9 is pivotal about the axis 2A. It has 
two longitudinally extending sides or flanks 12 that are traversed by the 
shaft 2 and a rear wall or web 13 connecting the sides 12. Journaled in 
these sides 12 to both sides of the input gear 3 are identical connecting 
pinions or gears 10 in permanent mesh with the gear 3. A compression 
spring 11 centered on a plane P defined by the axes 2A and 5A is 
compressed between the housing 8 and the rear wall 13 so as to normally 
urge the rocker 9 into the central solid-line position of FIG. 2. 
This rocker 9 can therefore move from the solid-line illustrated central 
position into two angled positions, one of which is shown in FIG. 2 in 
dot-dash lines. When in either of these angled positions the respective 
gear 10 meshes with the gear 4 and forms a torque-transmitting coupling 
between the gears 3 and 4. When in the solid-line central position there 
is no significant connection between the gears 3 and 4; that is the gear 4 
can rotate freely relative to the gear 3. 
Thus for power actuation of the nut 5 the motor shaft 2 rotates, for 
instance, in the clockwise direction. Due to the unavoidable friction 
between the parts on the rocker 9, this will have the effect of pushing 
down the right-hand side of the rocker 9 and lifting its left-hand side as 
seen in FIG. 2, thereby bringing the right-hand connecting gear 10, which 
will be rotating counterclockwise, into mesh with the gear 4. The result 
will therefore be clockwise rotation of the gear 4 and spindle 5. As soon 
as the motor 1 stops, the spring 11 will return the rocker 9 to the 
central solid-line position and decouple the right-hand gear 10 from the 
wheel 4. Opposite rotation of the gear 3 will oppositely tip the rocker 9 
and bring the left-hand gear 10 into mesh with the gear 4, thereby 
oppositely rotating same. 
When the motor 1 is not operating and, therefore, the rocker 9 is in the 
central position with the gears 10 and 4 decoupled, manual actuation of 
the lock 15 is possible simply by pivoting the lever 7 to force over the 
nut 6 and rotate the shaft 5. No matter what the position of the nut 6 on 
the shaft 5, power actuation, which is controlled by end-limit switches on 
the various lock parts, can take over at any time without having to 
resynchronize the positions of the device.