A preselected transmission has three friction clutches and one synchronized mechanical clutch assembly to provide five forward speed ratios. An additional mechanical clutch permits the addition of a reverse ratio. The clutches are combined with a gearing arrangement such that sequential or skip-shifting can be accomplished.

BACKGROUND OF THE INVENTION 
This invention relates to preselected shifting transmissions and more 
particularly to such transmissions that permit both sequential and 
skip-shifting patterns. 
Prior art sequential and skip-shifting transmissions are disclosed in U.S. 
Pat. No. 4,513,631, issued to Koivunen on Apr. 30, 1985, and U.S. patent 
application Ser. No. 705,206, filed Feb. 25, 1985 now U.S. Pat. No. 
4,610,177. Both of these documents are assigned to the assignee of this 
application. 
SUMMARY OF THE INVENTION 
The present invention permits ratio skip-shifting without the use of 
duplicate ratio gearing. The present invention uses only one mechanically 
synchronized clutch assembly for the forward gear ratios. Also the number 
of forward gear ratios can be increased in pairs by the addition of a 
single friction clutch and the appropriate ratio gear elements. The number 
of mechanically synchronized clutches remains at one even with the 
addition of two forward ratios. 
It is therefore an object of this invention to provide an improved 
preselected multi-ratio transmission having three selectively engageable 
friction clutches, one mechanically synchronized clutch assembly and four 
pairs of ratio gears which are selectively operable in combination to 
provide five forward gear ratios. 
It is another object of this invention to provide an improved preselected 
multi-ratio transmission having three selectively engageable friction 
clutches, two mechanically synchronized clutch assemblies, four pairs of 
ratio gears and a reverse idler gear which are selectively operable in 
combination to provide five forward gear ratios and one reverse ratio. 
It is a further object of this invention to provide an improved preselected 
ratio transmission having a plurality of selectively engageable friction 
clutches, one mechanically synchronized clutch assembly and a plurality of 
pairs of ratio gears sufficient to provide forward ratios equal in number 
to one less than twice the friction clutches, wherein the components are 
selectively operable in combination to provide an odd number of forward 
gear ratios in a manner which permits shifting to and across the 
centermost forward ratio.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the drawings, wherein like characters represent the same or 
corresponding parts throughout the views, there is seen in FIG. 1 a 
transmission, generally designated 10, having an input shaft 12 and an 
output shaft 14. The input shaft 12 has operatively connected therewith 
three rotating clutches 16, 18 and 20. The clutch 16 has drivingly 
connected therewith a pair of gear members 22 and 24. The clutch 18 has 
connected therewith a gear member 26, and the clutch 20 has drivingly 
connected therewith a gear 28. 
The gear 22 meshes with a gear 30 rotatably disposed on the output shaft 14 
and drivingly connected with one portion 32 of a mechanical double-acting 
synchronizer clutch 34. Another portion 36 of the synchronizer clutch 34 
is connected to a pair of gears 38 and 40 meshing respectively with the 
gears 24 and 26. 
The output member 42 of the synchronizer clutch 34 is drivingly connected 
with the output shaft 14 and with a gear member 44 which meshes with gear 
member 28 and a reverse idler gear 46. The reverse idler gear 46 is 
operatively connected through a single-sided mechanical synchronized 
clutch 48 with another reverse idler gear 50 which meshes with gear 24. 
The reverse idler gears 46 and 50 are connected with respective idler 
shafts 52 and 54. 
The friction clutches 16, 18 and 20 may be constructed in accordance with 
any of the well-known selectively engageable friction type clutches which 
may be engaged hydraulically, electrically or mechanically. The 
synchronizer clutches 34 and 48 can be constructed in accordance with the 
known synchronizer type clutches and may be manipulated either 
mechanically, electrically or hydraulically. Controls for such devices are 
well known. 
The friction clutches 16, 18 and 20 and the synchronizer clutch 34 can be 
selectively engaged in combination to provide five forward driving speeds 
as follows. 
The synchronizer clutch 34 is manipulated to provide a drive relationship 
between portion 32 and output shaft 14 thereby connecting gear 30 to the 
output shaft 14. Selective engagement of clutch 16 will transmit driving 
torque from the input shaft 12 through gears 22 and 30 to the output shaft 
14. This provides the first and lowest drive ratio of the transmission. 
For second ratio operation, the friction clutches 16 and 18 are 
interchanged using any of the well-known clutch control mechanisms such 
that drive torque from the input shaft 12 will be transmitted through 
gears 26 and 40, gears 38 and 24, and gears 22 and 30 to the output shaft 
14. 
The third and centermost drive ratio is accomplished by interchanging 
clutches 18 and 20 such that the input torque at shaft 12 is delivered 
through gears 28 and 44 to the output shaft 14. During third gear 
operation, the synchronizer clutch 34 is torque unloaded such that free 
manipulation thereof is possible. During third gear operation, the 
synchronizer clutch 34 provides disengagement between portion 32 and 
output shaft 14 and is moved into engagement to provide driving connection 
between portion 36 and the output shaft 14. 
After manipulation of the synchronizer clutch 34, the fourth ratio drive is 
established by simultaneously interchanging clutches 16 and 20. With 
clutch 16 engaged, input torque is delivered through gears 24 and 38 to 
the output shaft 14. The fifth and highest gear ratio is provided by 
interchanging clutches 16 and 18. With clutch 18 engaged, the input torque 
on input shaft 12 will be directed through gears 26 and 40 to the output 
shaft 14. 
Reverse gear is engaged with the vehicle stationary and the synchronizer 
clutch 34 in neutral by engaging the synchronizer clutch 48 and thereafter 
controllably engaging clutch 16 such that forwardly directed input torque 
on the shaft 12 is connected through gears 24 and 50, and gears 46 and 44 
of the output shaft 14. The reverse idler gears 50 and 46 provide for a 
rotation reversal between the input shaft 12 and the output shaft 14. 
From the above description, it will be appreciated that sequential shifting 
of the forward gear ratios, first through fifth, is easily accomplished. 
This is a conventional shifting pattern. However, with the present 
invention, it is also possible to provide skip-shifting from first gear to 
third gear to fifth gear in the following manner. Synchronizer clutch 34 
is manipulated to engage portion 32 and thereafter the clutch 16 is 
engaged to provide first gear operation. Selective interchange of clutches 
16 and 20 will permit a ratio change from first to third. During third 
gear operation, the synchronizer clutch 34 can be manipulated to engage 
the portion 36 after which the clutches 20 and 18 are interchanged to 
provide a ratio change from third to fifth. Downshifting from fifth to 
third to first can be accomplished by reversing the clutch interchanges. 
In some instances, it may be desirable to provide additional forward speed 
ranges. Additional forward speed ranges can be provided in pairs through 
the addition of a single friction clutch and gear member and an additional 
gear member being made drivingly connected with the synchronizer portion 
36. The additional gear ratios are provided by selective engagement of the 
added friction clutch and depending upon the condition of synchronizer 
clutch 34, the additional ratio will be either lower or higher than the 
centermost or central ratio provided by clutch 20 and the gears 28 and 44. 
The addition of a friction clutch will not inhibit the skip-shifting from 
a ratio below the central ratio to the central ratio and then skip-shifted 
above the central ratio. For example, in a 7-speed transmission, 
skip-shifting from first to fourth to sixth or seventh could be 
accomplished as could skip-shifting from second to fourth to sixth or 
seventh. 
From the above description, it should be evident that the 5-speed ratio 
transmission described is a basic element in providing a preselected 
skip-shifting transmission. The addition of gear ratios to the 
transmission is readily accomplished such that the overall transmission 
ratios can be expanded from five to seven to nine, etc. The limiting 
factor of adding transmission ratios is, of course, a physical one and is 
determined by the volume required for the transmission to fit in the 
vehicle. It should therefore be recognized that a family of transmissions 
can be provided by expanding the basic 5-speed transmission described 
herein. 
Obviously, many modifications and variations of the present invention are 
possible in light of the above teaching. It is therefore to be understood, 
that within the scope of the appended claims, the invention may be 
practiced otherwise than as specifically described.