Gear selector mechanism

A sleeve is splined to but axially slidable on a shaft between two gears rotatable relative to said shaft and having fixed lugs on their inner faces. A clutch ring is journalled on each end of the sleeve and provided with clutch dogs engageable with the lugs of one gear when the sleeve and ring are moved toward that one gear. A selector ring slides axially on the sleeve and when moved in one axial direction toward one of the gears it first positively clutches the advancing clutch ring to the sleeve then moves the sleeve and clutch ring toward that one gear to engage the clutch dogs of the advancing ring with the lugs on the one gear. Thereafter, when the selector ring is moved in the other direction, it first releases the clutched ring from the sleeve then repeats the above described clutching in the other direction.

BACKGROUND OF THE INVENTION 
This invention is in the field of gear selector mechanisms of particular 
utility in automobile transmissions but also useful in other environments. 
The invention disclosed herein constitutes an improvement of my prior U.S. 
Pat. No. 3,780,840. In my prior patent, a somewhat similar gear selector 
mechanism is dislcosed but it was found that difficulty was encountered in 
shifting to a lower ratio gear. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, a mechanism is provided wherein 
either of two adjacent members rotatably mounted relative to a shaft, may 
be selectively connected to that shaft in driving engagement by means of a 
first clutch ring movable into driving engagement with one member and a 
second clutching arrangement between that clutch ring and the shaft. In 
this way, a clutch ring drivingly engaged with one of the members may be 
disengaged from the shaft prior to its disengagement from the member, thus 
rendering this disengagement from the member easy and requiring little 
force irrespective of any tendency of that member and shaft to rotate at 
different speeds.

DESCRIPTION OF A PREFERRED EMBODIMENT 
Referring first to FIG. 1, an input shaft 2 is shown having a driving gear 
4 keyed thereon. An output shaft 6 is arranged coaxial to the shaft 2 but 
rotatable relative to the shaft 2 by means of the pilot bearing 8. An 
output gear 10 is journalled on the shaft 6, by means of any suitable 
bearing such as shown at 12, for rotation on the shaft 6. Gears 14 and 16 
keyed on countershaft 18 are in mesh with gears 4 and 10, respectively. 
Thus, if gear 4 is clutched to the shaft 6, a direct drive through the 
transmission is established with gear 10 free to rotate relative to shaft 
6. However, if gear 10 is clutched to shaft 6, instead of gear 4, a 
reduced speed drive from gear 4 through gear 14, shaft 18, gear 16 and 
gear 10 to shaft 6 is established. 
The structure to be described may be employed to selectively clutch either 
gear 4 or 10 to the shaft 6 and while a single such selective clutching 
mechanism is shown, it is to be understood that other similar devices may 
be provided on either shafts 6 or 18 to establish further gear ratios 
through the mechanism. As shown, the gear 4 is provided with a circular 
series of spaced lugs 20 extending from its inner face, that is, the face 
nearest the gear 10. Those lugs may be integral with the gear or 
separately secured thereto. In like manner, the gear 10 is provided with a 
circular series of spaced lugs 22 on its inner face. 
A selector sleeve 24 is slidably mounted on the shaft 6 by means of 
interengaging splines and grooves 26-27 whereby the sleeve is nonrotatable 
relative to shaft 6 but is capable of axial sliding movement thereon. The 
sleeve 24 is provided with a large diameter central portion 22 and reduced 
diameter end portions 30 separated by axially facing shoulders 32. On each 
of the reduced diameter portions 30, a clutch ring 34 is mounted for 
rotation relative to the sleeve 24. Each end of the sleeve 24 and each of 
the clutch rings 34 is identical so only one will be described in detail. 
A split ring retainer 36 holds each clutch ring 34 in close proximity to 
its adjacent shoulder 32 while permitting rotation between each clutch 
ring and the sleeve 24. Each of the clutch rings 34 is provided with a 
circular series of openings 38 therethrough and in each of which a clutch 
dog 40 is slidably mounted. The clutch dogs 40 are of the general shape 
best seen in FIG. 7, each being provided with an oblique end surface 42, 
for a purpose to be described. As best seen in FIG. 3, the slidable clutch 
dogs 40 are spring urged toward the adjacent gear by means of leaf springs 
42 bearing against the inner ends thereof. From FIG. 7 it will be apparent 
that opposed sides of each pair of clutch dogs 40 are spaced apart a 
distance substantially equal to the space between adjacent lugs 20 or 22 
on the gears. When clutch dogs 40 engage the lugs 20 in the manner shown 
in FIG. 7, the oblique surfaces 42 face obliquely inwardly in the space 
between the adjacent lugs 20. 
On its inner periphery, each clutch ring 34 is provided with an inwardly 
facing channel 44 (see also FIG. 2), the bottom or outer periphery of 
which is formed to define a multiplicity of curved sockets 46. It is to be 
noted that the number of sockets 46 in the channel 44 is much greater than 
the number of clutch dogs 40 or gear lugs 20 or 22. 
The reduced diameter portions 30 of the sleeve 24 are provided with a 
plurality of guide passages 48 aligned with the respective channels 44 and 
clutch pins 50 are radially slidable therein. Each radial passage 48 
communicates with an axial passage 52 in which a cam member 54 is 
slidable, the cam member 54 and pins 50 being provided with matching cam 
or wedge surfaces at 56. In like manner, matching cam or wedge surfaces 58 
between cam member 54 and radial member 60 are arranged as shown. Each of 
the radial members 60 slides in an opening 62 extending from passage 62 to 
the outer periphery of the central portion 28 of sleeve 24. The upper or 
outer ends of the radial members 60 are bevelled as shown at 64 and 
cooperate with a bevelled or cam surface 66 on a selector ring 68 axially 
slidable on the outer peripheral surface of the central portion of sleeve 
24. The selector ring 68 has an outer peripheral central rib 70 and a 
shift fork device 72 is provided with spaced flanges 74 on opposite sides 
of the ribs 70 with substantial space between those flanges and the rib. 
Each of those spaces is occupied by an undulating flat spring 76 and a 
retainer ring 78. Since the shift fork and its flanges 74 embrace only the 
upper half of the ring 68, the retainer rings 78 hold the springs 76 
against rib 70 around the lower half of ring 68. The springs 76 normally 
hold the shift fork 72 in centralized relation to the rib 70. As also 
shown in FIG. 1, a spring urged ball detent 80 is mounted in shaft 60 in 
position to engage any one of three recesses 82 in an aligned spline on 
the sleeve 24. The ball detent is of conventional construction and serves 
to releasbly hold the sleeve 24 in a selected one of three different 
positions. 
As shown in FIG. 1, the parts are in "neutral" position, that is, no torque 
can be transmitted from shaft 2 to shaft 6 since neither gear 4 or 10 is 
clutched to shaft 6. If it is desired to establish direct drive between 
the shafts 2 and 6, the shift fork 72 is moved to the left as shown in 
FIG. 4. This compresses one of the undulating springs 76 and applies the 
resilient pressure to a side of rib 70. This pressure is not sufficient to 
overcome the restraint provided by ball detent 80 but is sufficient to 
cause the left hand cam surface 66 of member 68 to depress radial members 
60 and thereby effect camming of the associated clutch pins 50 outwardly 
into the channel of clutch ring 34. The pins 50 are forced outwardly 
sufficiently far to seat their correspondingly shaped outer ends in the 
recesses 46 and thereby effect a positive clutching of the left hand 
clutch ring 34 to the sleeve 24. It is to be understood that the 
illustrated camming and clutching elements 50-60 are duplicated around the 
sleeve 24, as best shown in FIG. 2, to thus provide secured clutching for 
the transmission of substantial torque. It is also to be noted that the 
selector ring 68 is so shaped and dimensioned that, when it is in the 
position of FIG. 4, its right hand end still overlies the radial members 
60 at that end to sleeve 24 to prevent their leaving their respective 
openings 62. After the parts have been moved to the position of FIG. 4 as 
thus described, further force applied toward the left by shift fork 72 and 
spring 76 will move ring 68 into abutment with left hand ring 34 and thus 
urge sleeve 24 to the left and overcome the restraint of ball detent 80 
and, particularly the resilient force of spring 76, will cause the sleeve 
24 to snap to the left and thereby engage clutch dogs 40 in the spaces 
between lugs 20 of gear 4, the parts then being in the position shown in 
FIG. 5 with the gear 4 being clutched to the shaft 6 for direct drive. 
While not illustrated in the drawings, the final rapid movement of sleeve 
24 toward gear 4 may result in the ends of some of the clutch dogs 40 
impinging on the axially inner faces of lugs 20 rather than entering 
directly into the spaces between those lugs. Obviously, if that occurs, 
only alternate clutch dogs 40 will hit the tops of the lugs 20 and the 
intermediate clutch dogs will enter the space between lugs 20. However, 
that will not prevent sleeve 24 from moving to the position shown in FIG. 
5 since the leaf springs 42 permit those dogs that engage the tops of the 
lugs to slide inwardly in their corresponding channels 38. Any tendency of 
the gear 4 and shaft 6 to rotate at different speeds under these 
conditions will result in the clutch dogs seeking alignment with the 
spaces between lugs 20 and when that occurs the deflected springs 42 will 
force the retracted clutch dogs into the space between lugs on the gear. 
The angled or oblique ends 42 on the clutch dogs result in the capability 
of the clutch dog, which initially entered a space between lugs 20, to be 
cammed out of that space and over one of the lugs 20 in the event that 
relative rotation beteen the gear 4 and shaft 6 moves that particular lug 
in the required direction. If relative rotation is in the other direction, 
the retracted lug will merely moved into engagement with a side face of 
one of the lugs 20 and its adjacent clutch dog will then be in a position 
to be spring urged inwardly to the position of FIG. 7. Clearly, in this 
position, direct drive will be maintained. The engaging faces between 
clutch dogs 40 and lugs 20 are in radial planes and there is, therefore, 
no resultant force urging the parts to separate. After the parts have been 
moved to the position of FIG. 5 and force on the shift fork 72 is 
released, ball detent 80 holds the sleeve 24 in this position and springs 
76 return the shift fork to centralized relation to rib 70, all as shown 
in FIG. 5. 
To effect disengagement of the parts from the FIG. 5 position, to 
"down-shift" by clutching gear 10 to shaft 6, the shift fork 72 is moved 
to the position shown in FIG. 6. This energizes one of the springs 76 and 
applies lateral pressure to the selector ring 68 to move the same to the 
position of FIG. 6 wherein the clutch pins 50 previously engaged with the 
left hand clutch ring 34 are released and the clutch elements 50, on the 
right hand side of the figures are forced outwardly into clutching 
engagement with the right hand clutch ring 34. The recesses 46 and the 
ends of clutch pins 50 are correspondingly shaped such that, with the 
parts in the position of FIG. 6, any torque between gear 4 and ring 34 
will cause the pins 50 to cam inwardly free of the recesses 46. This 
selective declutching of one clutch ring and clutching of the other to the 
sleeve 24 is accomplished without axial movement of that sleeve, the 
sleeve being retained in its positive drive position by ball detent 80. In 
this condition, it is to be noted that the clutch ring 34 is no longer in 
clutched engagement with the sleeve 24 but is free to rotate thereon. 
Thus, the application of further force to the shift fork 72, toward the 
right, as seen in FIG. 6, will overcome the restraint of ball detent 80 
and permit the sleeve 24 to move completely to the right to engage the 
right hand clutch ring and its clutch dogs 40 with gear 10 and its lugs 
22. No torque of any substantial magnitude is being applied to the left 
hand clutch ring 34 and the same may, therefore, be readily and easily 
withdrawn from gear 4 and the engagement of the right hand clutch dogs 40 
with lugs 22 of gear 10 occurs exactly as previously described in the 
description of the initial manipulation of the apparatus and thus a 
reduced speed drive is established from shaft 2 to shaft 6. 
While a single specific embodiment of the invention has been shown and 
described, it is to be understood that many modifications may be made 
within the scope of the appended claims. For example, other means than the 
elements 50, 54, 60 may be employed to effect selective clutching of the 
rings 34 to the sleeve 24, or its equivalent, in response to axial 
movement of shift fork 72.