Park lock and gear shift for a vehicle transmission

A cable and cam operated vehicle park lock and range shift mechanism whereby the linear movements operating the mechanism are transformed into a rotational movement for operating an eccentric cam and a shift fork for operating the park lock and range shift in the transmission.

This invention relates to a transmission and more particularly to a means 
whereby forces causing reciprocal movements are transformed into 
rotational movements to operate an eccentric cam for the park lock and a 
shift rail for selectively operating the range shift in a vehicle 
transmission. 
The conventional vehicle transmission is operated by a shift lever at the 
operator station. A suitable linkage is provided between the shift lever 
and the transmission for shifting of the gears to provide a desired speed 
ratio for the operator. When parking and shifting is accomplished with a 
single lever as is sometimes done in automobiles the gears cannot be 
shifted while the vehicle is in the park lock position. When the operator 
station is resiliently mounted relative to the vehicle chassis, there is 
relative movement between the operator and the controls at the operator 
station relative to the vehicle chassis. A linkage which accommodates the 
relative movement between the operator station and the vehicle chassis 
must be used to provide force and motion transmission from the shift lever 
at the operator station for shifting gears or operating the park lock. 
The modern tractor may employ a five speed main transmission preceded by a 
two or three speed power shift transmission which multiplies the range of 
the main transmission. Similarly, a range transmission may be positioned 
subsequent to the main transmission which also in turn multiplies the 
speed ratios of the main transmission. The provision of the power shift 
transmission and the range transmission provides a more versatile power 
transmission for the overall tractor power train. 
Generally, the range transmission is positioned rearwardly and remote of 
the operator station. Accordingly, some form of linkage must be provided 
to accommodate the relative movement between the operator station and the 
range transmission as well as allowing for the remote location of the 
range transmission relative to the operator. Accordingly, this invention 
provides such a vehicle park lock and range shift transmission in which 
the operator can control shifting of the range transmission and operating 
the park lock which locks the drive shaft of the vehicle and which can be 
accomplished from the operator station. 
Accordingly, it is an object of this invention to provide a cable operated 
vehicle park lock and range transmission shift mechanism. 
It is another object of this invention to provide a rotary eccentric cam 
operated park lock mechanism. 
It is further object of this invention to provide a rotary operated shaft 
for operating a shift rail and a shift fork in a vehicle range shift and a 
rotary operated shaft operating a park lock with an interlock connected 
between the rotary shafts for selectively and alternatively operating the 
range shift or the park lock mechanism. 
The objects of this invention are accomplished by providing a vehicle 
transmission having a cover plate for supporting two rotating shafts for 
operating the range shift and the park lock mechanisms. The rotating 
shafts are rotatably mounted on the cover plate for the transmission and 
can be operated by suitable reciprocating force transmission means from 
the operator station to the cover plate. One of the rotating shafts in 
turn operates a shift operating arm engaging a shift rail carrying a 
shifting fork for shifting a two speed range shift. The second of the 
rotating shafts operates an eccentric cam bearing against the cam follower 
arm operating a pawl arm of a lever pivotally mounted for selective 
engagement of the pawl with the drive shaft gear for locking the vehicle 
drive shaft. An interlock is provided to selectively operate either the 
park lock or the range shift mechanism and preventing operation of the 
other mechanism. The transmission can be remotely positioned relative to 
the operator station.

Referring to the drawings, FIG. 1 shows a cross section view through an 
opening 2 on the vehicle transmission 1. The cover plate 3 is bolted to 
the transmission housing by a plurality of bolts 4. The cover plate 3 
forms a bearing casing 5 for the range shift operating shaft 6 and the 
park lock operating shaft 7. The bearing casing 5 supports the bearing 8 
and bearing 9 which rotatably support the gear shift operating shaft 6. 
The gear shift operating shaft 6 extends through the gear shift arm 10 for 
pivotally moving the gear shift arm for slideably moving the shifting fork 
11 on the shift rail 12. The gear shift operating arm 13 is connected to 
the outer end of the gear shift operating shaft 6 and is firmly fastened 
by the lock washer 14 and the nut 18 on the threaded end of the gear shift 
operating shaft 6. The shift fork 11 slides with the shift rail 12 to 
shift the clutch collar and drive gear 45. 
The park lock operating shaft 7 is rotatably mounted on the bearings 19 and 
20. The park lock operating shaft carries the oil seal 21 which is locked 
in by the lever 22 on the outer end of the park lock operating shaft 7. 
The other end of the park lock operating shaft is formed with a spline 23 
which engages a mating spline of the eccentric roller 24. The eccentric 
roller forming the cam surface 25 is locked into position by a retainer 
ring 26. The eccentric roller 24 defining the cam 25 bears against a 
follower surface 28 on the actuator arm 29 of the pawl lever 30. The pawl 
lever 30 is pivotally mounted on a shaft 31 mounted in supporting 
structure of the cover plate 3. The pawl lever 30 defines a gear segment 
32 on the pawl arm 130 to engage the gear teeth 33 of the clutch collar 
and drive gear 45. The clutch collar and drive gear 45 are connected 
through the spline to the drive shaft 40 of the vehicle. 
The actuator arm 29 of pawl lever 30 is biased to a release position of the 
pawl arm 130 by the spring 34. The spring 34 is mounted on the spring seat 
35 in the spring support 36. 
Integral with the cover plate 3 are the supporting flanges 136 and 37 which 
slideably support the shift rail 12. These flanges also form the supports 
38 and 39 which carry the shaft 31 pivotally mounting the pawl lever 30. 
The structure is shown in FIGS. 1 and 2 as well as FIG. 8 which shows a 
plan view of the cover plate and the supporting flanges carrying the shaft 
31 supporting the pawl lever 30 and shift. The gear shift operating shaft 
6 and the park lock operating shaft 7 are shown in FIG. 8. The mounting of 
the eccentric roller 24 is shown on the end of the shaft 7. 
Referring to FIG. 3, the drive shaft 40 is shown supporting the gears 41 
and 42. Each of the gears 41 and 42 carry clutch teeth 43 and 44 as 
indicated. The clutch collar 45 is splined at its internal periphery and 
slideably engages the clutch teeth 43 and 44 of the gears 41 and 42, 
respectively, when the shift fork 11 is shifted. The drive gears 46 and 47 
are carried on the input shaft 48 for selectively driving either gear 41 
or 42. The gears are in constant engagement with each other except the 
drive may go through gear 46 and gear 41 or gear 47 and gear 42 
selectively and alternatively depending upon the position of the clutch 
collar 45. 
FIG. 4 illustrates the operation of the eccentric roller 24 which defines 
the cam surface 25. As the park lock operating lever 22 is rotated, the 
cam rotates about the axial center 49 of the park lock operating shaft 7. 
This in turn moves the eccentric roller 24 from the position 50 to the 
position 51. The position 50 shows the release position of the cam and 
position 51 shows the actuated position in which the park lock is engaged. 
FIG. 5 shows an interlock pin 52. The interlock pin 52 is moved to the 
position shown in FIG. 5 when the park lock actuating shaft 7 is rotated. 
The recess 53 rotates beyond the end of the interlock pin 52 and the 
periphery of the shaft 7 presses the pin into the recess 54 of the gear 
shift operating shaft 6. Conversely, when the gear shift operating shaft 6 
is rotated, the recess 54 rotates beyond the end of the pin and the 
periphery of the shaft forces the pin 52 into the recess 53 on the park 
lock operating shaft 7. Accordingly, the park lock cannot be engaged while 
the range shift is operating in either the high or the low gear range 
position. When the park lock is engaged, the transmission cannot be 
shifted in either of the high or low ranges. 
The shift rail 12 carries the gear shift fork 11 which is nonrotatably 
mounted on the shift rail 12. The shift fork is fastened to the shift rail 
by the bolts 56 and 57. The slot 160 slideably receives the pin 55 mounted 
in flange 136. 
The high, low and neutral positions of the shift rail are provided. The 
detent element 58 seats in the high, neutral and low detent positions 59, 
60 and 61. The detent element 58 is biased to engaged position by the 
spring 62. The end view of the shift rail is shown in FIG. 7. 
Referring to FIGS. 9, 10, 11 and 12, the control console 64 is shown. The 
lever 65 is pivotally mounted on the sleeve 66. The spring 67 normally 
biases the lever 65 against the shift segment 71. The shift lever 65 is 
shown in the park lock position with the lever 65 abutting against the tab 
68 as shown in FIG. 11. When the lever is moved to the left against the 
biasing force of spring 67, it can be moved forwardly to the slot 168 
showing the neutral position for the lever 65. The range shift segment 69 
can also be shifted forward or reverse to operate the range shift segment. 
The range shift transmission can be shifted from high to low by movement 
of the shift segment 69. 
The park lock and range shift mechanism operates in the following described 
manner. The lever 65 is pivotally mounted on the sleeve 66 which is 
supported on the shaft 70. The lever can be shifted by selectively 
engaging the range shift segment 71 or the park lock segment 72. This is 
accomplished by moving the lever left or right as viewed in FIG. 9. The 
range shift segment 71 is in the gear shifting segment and the shift lever 
can be pivotally moved between the high, low and neutral positions as 
shown in FIG. 10. Movement of the cables by the segments operate the 
levers for shifting the range transmission or the park lock. As the park 
lock segment 72 is moved clockwise as viewed in FIG. 10, the cable 73 
pivots the lever 22 in a counterclockwise direction which in turn operates 
the cam 24. The cam is rotated in a counterclockwise direction which 
depresses the actuator arm 29 of the pawl lever 30 as the cam bears 
against the surface 28. The park lock lever is in the fully actuated 
position as shown in FIGS. 1 and 2. The lever then is moved to the 
position shown in FIG. 11 in which the lever is locked to prevent it from 
counterclockwise rotation while the park lock is engaged. 
Simultaneously, the interlock pin 52 will move to the position as shown in 
FIG. 5 in which the pin is received in the recess 54 locking the gear 
shift operating shaft 6 from moving while the park lock is engaged. 
Similarly, when the park lock mechanism is released, the lever is moved to 
the left as viewed in FIG. 9 and rotated in a counterclockwise direction 
as viewed in FIG. 10. This releases the park lock as the cam rotates in a 
clockwise direction as viewed in FIG. 2. The lever 65 is then returned to 
the neutral position as shown in FIG. 12. In this position, the lever 65 
can then be rotated clockwise or counterclockwise to shift the range shift 
to a low position or a high position as shown in FIG. 10. Movement of the 
lever 65 rotates the range shift segment 69 and also transmits motion 
through the cable 76 whereby a clockwise rotation of the lever 65 will 
cause a counterclockwise rotation of the shift lever 13 and moves the 
shift arm 10. This, in turn, moves the shifting fork 11 as shown in FIG. 
2. Accordingly, shifting in the opposite direction will carry the range 
shift segment 69 and shift the arm 13 and gear shift arm 10 in the 
opposite direction and move the shifting fork to shift the gears into high 
range. Likewise, the interlock pin 52 will move into the recess 53 as the 
gear shift operating shaft 6 is rotated and thereby prevent any movement 
of the park lock to lock the drive shaft when the gears are shifted.