Vehicle floor mounted transmission shift lever with steering column backdrive linkage

A floor mounted transmission shift lever is connected to the steering column backdrive and locking mechanism. A separate linkage is connected between the steering column backdrive and the transmission shift control mechanism.

This invention relates to transmission shift controls and more particularly 
to floor mounted, manually operated, automatic transmission shift controls 
with a backdrive connection to the steering column. 
Prior art floor mounted transmission shift controls for automatic 
transmissions generally have a linkage or flexible cable connected 
directly between the shift lever and the transmission mounted shift 
control mechanism. In some instances, these transmission shift controls 
also include a linkage or flexible cable connection from the transmission 
mounted control to the steering column backdrive. These shift control 
systems, wherein the locking mechanism of the steering column is used to 
prevent shifting from the "Park" mode, are not always sufficiently rigid 
to prevent the shift lever from being forcibly moved from the "Park" 
location even though the steering column lock mechanism has been actuated. 
The present invention prevents excessive loads from being transmitted 
between the floor mounted shift lever and the transmission mounted shift 
control by interposing the steering column mounted locking mechanism 
between these two structures. Manual force applied to the transmission 
shift lever is absorbed by the steering column backdrive system and cannot 
be directly imposed upon the transmission mounted shift control mechanism. 
When the steering column locking mechanism is operated to permit normal 
vehicle operation, the normal loads imposed on the shift lever will then 
be transmitted to the shift control mechanism. 
It is an object of this invention to provide an improved floor mounted, 
manually operated shift control mechanism for a vehicle having an 
automatic transmission. 
It is another object of this invention to provide an improved floor 
mounted, manually operated shift control mechanism in a vehicle having an 
automatic transmission wherein the shift lever is drivingly connected to 
the steering column backdrive mechanism which in turn is connected to the 
transmission shift control mechanism. 
A further object of this invention is to provide an improved floor mounted, 
manually operated shift control mechanism for an automatic transmission 
wherein the shift lever is drivingly connected to the transmission 
backdrive mechanism through a flexible cable and wherein the backdrive 
mechanism is drivingly connected to the transmission shift control through 
a linkage mechanism.

There is seen in FIG. 1, a conventional floor mounted shift control lever 
assembly generally designated 10, which is drivingly connected to a 
conventional steering column mounted backdrive generally designated 12 by 
a flexible cable 14. The steering column backdrive mechanism 12 is 
connected by a linkage system generally designated 16 which is connected 
to operate a conventional manual shift valve S.V. which is disposed within 
a transmission 18. The flexible cable 14 may be constructed in accordance 
with the teaching of U.S. Pat. No. 3,752,008 so as to be adjustable 
between its connections at ends 20 and 22. The internal cable member of 
the flexible cable, designated 24, is connected to a pivotally mounted 
manual transmission lever 26. The lever 26 is pivotally mounted on a 
bracket 28 which is secured to the vehicle floor pan, not shown, in a 
conventional manner. The cable 24 is also connected to a lever 30 which is 
a component in the steering column backdrive 12. The lever 30 is connected 
to a conventional transmission shift control tube 32 which extends 
concentric with a conventional steering column mast jacket 34. 
The transmission shift control tube 32 is connected to a steering column 
locking mechanism which may be constructed in accordance with U.S. Pat. 
No. 3,490,255 issued Jan. 20, 1970, and assigned to the assignee of the 
present application. Such steering column locking mechanisms are 
well-known so that a description of the mechanism is not considered 
necessary since those familiar with the art will be well aware of their 
operation and structure. It is sufficient to note that these steering 
column locking mechanisms are operable to prevent rotation of the shift 
tube 32 when the vehicle ignition key is moved to the "Lock" position. 
Also connected to the lever 30 is one end of a link 36 which has the other 
end thereof connected to a bell crank 38. The bellcrank 38 is secured to a 
rod 40 which has one end 42 rotatably mounted in a bracket 44 secured to a 
vehicle frame 46. The other end of rod 40 is connected to a bracket 48 
which is rotatably mounted in the transmission 18 and is operatively 
connected in a well-known manner to the transmission manual shift control 
valve S.V. 
When the steering column backdrive mechanism 12 is locked, any manual force 
exerted on the shift lever 26 will be transmitted through cable 24 to the 
lever 30. The lever 30 will, in most instances, rotate slightly to 
accommodate the production tolerances which are present. However, this 
rotation will not permit the linkage 16 to move an amount sufficient to 
permit the transmission control to be moved from the "Park" position. It 
should also be noted that the manual forces exerted on the manual lever 26 
and therefore cable 24, cannot be transmitted directly to the transmission 
shift linkage 16 as they will be absorbed by the steering column backdrive 
and locking mechanism. Therefore, it should be apparent that the above 
described control mechanism prevents the transmission control from being 
forcibly removed from the "Park" position when the steering column locking 
mechanism has been actuated.