Motion transmitting and timing mechanism

A motion transmitting and timing mechanism including an input gear 36, a timing gear 44 rotatable about an axis 50 and meshed with the input gear 36, and an output gear 64 rotatable about the axis 50 and shiftable along the axis into positions in and out of a plane including the input gear 36. The output gear 64 has a toothed sector 66 and an untoothed sector and a spring 76 and detent 72 arrangement normally maintain the untoothed sector in axial alignment with the input gear 36. A threaded connection 46, 70 between the timing gear 44 and the output gear 64 effects axial movement of the output gear 64 upon relative rotation between the two and a jaw 82 carried by the timing gear 44 is engageable with the output gear 64 for moving the toothed sector 66 into mesh with the input gear 36.

FIELD OF THE INVENTION 
This invention relates to a motion transmitting mechanism which 
additionally incorporates a timing function. 
BACKGROUND OF THE INVENTION 
In a number of mechanical systems, as, for example, door actuating systems, 
there is a need for some sort of a drive to provide a motion input to part 
of the system to cause some sort of predetermined movement which must be 
precisely followed by some differing form of movement. For example, in a 
door actuation system as mentioned previously, a drive unit may be 
utilized to first move the door from an opened position to a closed 
position at which time a hook or a latch is operated to latch the door in 
the closed position. 
Subsequently, when the door is to be opened, the drive unit is operated to 
first release the latch and then move the door from the closed position to 
the open position. 
While these sequential functions can be performed by any of a variety of 
means including electrical or electronic control circuits, in some 
instances, it is desirable to accomplish them mechanically with a simple 
and reliable mechanism which provides for both the transmission of motion 
from a drive unit to a work piece such as a door latching system and the 
timing of the motion transmission, that is, the transmission of the motion 
only at a predetermined time during an operational cycle of the system in 
which the mechanism is utilized. 
The present invention is directed to the provision of such a mechanism. 
SUMMARY OF THE INVENTION 
It is the principal object of the invention to provide a new and improved 
motion transmitting and timing mechanism. More specifically, it is an 
object of the invention to provide such a mechanism which is simple and 
reliable. 
An exemplary embodiment of the invention achieves the foregoing object in a 
mechanism including an input gear. A timing gear is rotatable about an 
axis and is meshed with the input gear. An output gear is rotatable about 
the axis and is shiftable along the axis into positions in and out of a 
plane including the input gear. The output gear has a toothed sector and 
an untoothed sector. Means are provided for normally maintaining the 
untoothed sector in axial alignment with the input gear and there are 
means responsive to rotation of the timing gear for axially moving the 
output gear between its positions. The mechanism includes means operated 
by the timing gear and engageable with the output gear when the output 
gear is in the previously mentioned plane for moving the toothed sector 
into mesh with the input gear. Upon such occurrence, the output gear will 
be driven to effect motion transmission. At the same time, timing is 
accomplished in that a certain amount of rotation of the timing gear is 
required before the output gear is moved into the plane whereat it can be 
engaged with the input gear. 
In a preferred embodiment, the input gear is a worm and the output gear is 
a sector gear. 
The invention contemplates that the responsive means comprise a threaded 
connection between the timing gear and the output gear. 
The invention also contemplates the provision of an output lever pivoted 
about the rotational axis of the timing gear and the output gear, with the 
output gear having a splined connection to the lever. 
In a highly preferred embodiment, a spring and a stop cooperate together to 
normally maintain the untoothed sector in axial alignment with the input 
gear and the spring additionally serves to resist rotation of the output 
gear. Thus, when a threaded connection interconnects the output gear and 
the timing gear, rotation of the timing gear relative to the output gear 
will normally occur due to the resistance to rotation of the output gear 
provided by the spring to consequently effect the axial movement of the 
output gear. 
The invention also contemplates that the mechanism be utilized in a closure 
system including a door moveable between open and closed positions and 
having latch means for latching the door in the closed position as well as 
a motor for moving the door between the positions. In such a system, the 
motor is coupled to the worm and the output gear is coupled to the 
latching means. 
Other objects and advantages will become apparent from the following 
specification taken in connection with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
One environment of intended use of a motion transmitting and timing 
mechanism made according to the invention is illustrated in FIG. 1 in the 
form of a door actuation system. In particular, there is provided a door 
10 which may be moved between open and closed positions as indicated by an 
arrow 12. To move the door 10 between such positions, there is provided a 
door opener 14 connected by any suitable linkage such as shown 
schematically at 16 to the door 10. A bi-directional motor 18 is adapted 
to drive the door operator 14. Depending upon which direction the motor 18 
is operated, the door 10 will either open or close. 
The system also includes one or more latches 20 that are mounted for 
movement to latch the door 10 in a closed position. To drive the latches 
20, the timing and motion transmitting mechanism of the invention is 
employed as a latch operator 22. The same is driven by the output of the 
door operator 14 or, if desired, by the motor 18 itself. In either event, 
in the system illustrated, the mechanism of the invention is adapted to 
time the operation of the latches 20 and cause their operation through 
motion transmission at predetermined points in an operational cycle. 
For example, if the door 10 is in an opened position, the motor 18 may be 
energized in one direction to initiate operation of the door operator 14 
which will in turn cause the door 10 to begin to move towards a closed 
position. This actuation will also be applied to the latch operator 22 
which will be in a timing mode of operation but not a motion transmitting 
mode of operation. 
At some predetermined point in the operation of the system, the door 10 
will be in a closed position and the latch operator will enter its motion 
transmission mode to cause the latches 20 to latch the door 10. 
When the motor 18 is operated in the reverse direction to move the door 10 
from the closed position to the open position, initially the latch 
operator will be in a motion transmitting mode causing the latches 20 to 
release from the door 10. After that has occurred, the latch operator 22 
will revert to a timing mode which essentially acts to reset the mechanism 
to an initialized position when the door reaches its fully opened 
position. 
Turning now to FIGS. 2 and 3, the mechanism of the invention will be 
described in greater detail. The same may include a mounting bracket 30 
having feet 32 securable to a wall or the like. At the upper end of the 
mounting bracket 30, bearings 34 are provided to journal a worm 36 of 
conventional construction which serves as an input gear. The worm 36 is 
thus to be coupled to the motor 18, either directly or via the door 
operator 14, as desired. 
As best seen in FIG. 2, the bracket 30 includes a central opening 38 which 
receives a bearing 40. The bearing 40, in turn, journals the hub 42 of a 
timing gear 44 which is meshed with the worm 36. For purposes to be seen, 
the interior of the hub 42 is threaded as at 46. 
A cap-like element or cover plate 48 acts in conjunction with the bracket 
30 to define a housing for the mechanism component and, in addition, 
stationarily mounts a shaft 50 which is on the axis of rotation of the 
timing gear 44. By means of bearings 52, the shaft 50 journals the hollow 
shaft 54 forming one end of an output lever 56. The output lever 56 may be 
connected by any suitable linkage (not shown) to the hooks 20. 
The shaft 54 of the lever 56 has exterior splines 58 which slidably mate 
with interior splines 60 in the hub 62 of a sector gear 64. As seen in 
FIG. 3, the sector gear 64 includes a toothed segment 66 of approximately 
30.degree., the remaining 330.degree. about the sector gear 64 being 
untoothed. However, depending upon the actual application and the timing 
sequence required, the toothed sector 66 could occupy a greater or a 
lesser number of degrees. 
On the exterior of the hub 62, and pinned thereto by means of a pin 67, is 
an externally threaded sleeve 68 having threads 70 engaged with the 
threads 46 on the interior of the timing gear hub 42. 
As a result of this configuration as well as the presence of the 
interengaging splines 58 and 60, it will be appreciated that when the 
timing gear 44 is rotated, if the sector gear 64 does not rotate 
therewith, it will slide on the splines axially along the lever shaft 54 
as the threads 70 advance into or out of the threads 46. 
The cover plate 48 includes a generally axially extending finger 72 which, 
as seen in FIG. 3, is adapted to abut the sector gear 64 on a side 74 
thereof. A coil spring 76 has one end 78 affixed to the stationary shaft 
50 and its opposite end 80 secured to the lever arm 56. The arrangement is 
such that a spring bias is applied to the lever arm 56, and thus to the 
lever shaft 54 and the sector gear 64 engaged therewith to bias the sector 
gear 64 into engagement with the finger 72 which then serves as a detent. 
By thus biasing sector gear 64, the spring 76 cooperates with the finger 
72 to resist rotation of the sector gear 64 and to normally place the 
untoothed sector of the gear 64 in axial alignment with the worm 36. As a 
consequence of such resistance, the aforementioned axial movement of the 
sector gear 64 toward or away from the timing gear 44 will occur. 
As seen in FIGS. 2 and 3, near its periphery, at one location thereon, the 
timing gear 44 carries a lateral projection or jaw 82. As can be 
appreciated from FIG. 2, the jaw 82 normally will be in no position to 
engage the sector gear 64, being axially spaced therefrom. However, when 
relative rotation between the timing gear 44 and the sector gear 64 has 
occurred to a sufficient extent as to cause the sector gear 64 to be 
advanced to the right as viewed in FIG. 2 so as to be within a plane 
nominally defined by the worm 36 and the timing gear 44, the jaw 82 will 
be in a position as to be engageable, under continued rotation of the 
timing gear 44, with the side 74 of the sector gear 64. When such 
engagement incurs, continued rotation of the timing gear 44 will drive the 
sector gear 64 into engagement with the worm 36 and the latter will then 
drive the former. Such motion of the sector gear 64 will be, of course, be 
transmitted to the lever 56 by reason of the splined connection between 
the two. Thus, such movement may be utilized to engage the latches 20 as 
mentioned previously. 
Once the latches 20 are fully engaged, the drive or motor 18 will typically 
stall or can be turned off by other means such as limit switches. In any 
event, at such time, the sector gear 64 will be engaged with the worm 36. 
When it is desired to reverse operation of the system, the motor 18 is 
driven in the opposite direction resulting in the worm 36 driving the 
sector gear 64 in a clockwise direction as viewed in FIG. 3. Ultimately, 
sector gear 64 will disengage from the worms 36 and, under the bias of the 
spring 76, revert to the position illustrated in FIG. 3. Continued 
operation of the motor 18 will result in the sector gear 64 moving axially 
to the left as viewed in FIG. 2 until the original starting position is 
achieved. 
It is to be noted that the location of the jaw 82 is such that the gear 
The mechanism, in its timing mode, consumes very little energy since all 
that is occurring is idle rotation of the timing gear 44 and relatively 
slow axial movement of the sector gear 64. However, when the mechanism has 
timed out, a high torque is provided to the lever 56 which ideally suits 
the mechanism for utilization in a door actuation system where large 
forces may be required to operate the latches. 
The mechanism is of simple construction and, as a consequence, highly 
reliable.