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[Refer section 10; rule 13] COMPLETE SPECIFICATION


1 TITLE OF THE INVENTION

2 APPLICANTS


M/S MAHINDRA & MAHINDRA LTD GATEWAY BUILDING, APOLLO BUNDER, FORT, MUMBAI400001. MAHARASHTRA. INDIA A Company registered under the Indian Companies Act, 1913 NATIONALITY: INDIA

he following specification particularly describes the nature of the invention and the manner in which it is to be performed:-

*Field Of Invention:
The present invention relates to provide a simpler, compact, flexible and mechanically operated Forward / Reverse changeover assembly unit in a transmission system of an off-highway vehicle(s) like tractor(s) or similar vehicle(s), which will enable the transmission system to produce equal number of vehicle output speeds both in forward and reverse direction of a vehicle(s).
Background Of the Invention :
The off-highway vehicle(s) like tractor(s) or similar vehicle(s) (hereafter mentioned as vehicle) is used in the field of agricultural, construction and material handling for different operations and / or purposes. The nature of work being carried out by these types of vehicles requires the vehicles to be operated freqliently in both forward and reverse direction having equal speed range.
The vehicle manufacturers have addressed the requirement of equal speeds both in forward and reverse direction. To overcame the above requirement a feature of forward / reverse shuttle mechanism is being adopted as a part of conventional transmission system of a vehicle. The above mentioned requirement has been fulfilled by using this mechanism, whereas following are the limitations;
- Implementation and / or adaptation of this mechanism in a conventional transmission
system (without forward / reverse shuttle mechanism and hereafter mentioned as existing
transmission system) requires re-designing of whole existing transmission system
(including housing(s) and transmission system layout), leading to losses in terms of time
and development cost.
- At the same time changes in said existing transmitting system for accommodating
forward / reverse shuttle mechanism, again requires re-design and / or modification in
related vehicle components, which further leads to losses in terms of time and
development cost.
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- If the old customer (having vehicle with existing transmission system) wants to changeover for equal speeds both in forward and reverse direction will face more difficulties to go for forward / reverse shuttle mechanism.
US Patent 4484,488 uses a forward / reverse changeover apparatus for achieving equal number of vehicle output speeds in both forward and reverse direction. An apparatus is comprising of first and second hydraulically operated multiplate clutches, input and output shaft, in which one of the multiplate clutch is directly connected to the said output shaft whereas another is through the free rotational reverse gear. The said first and second multiplate clutches are actuated by means of hydraulics system.
Thus the Invented apparatus is completely hydraulically operated which makes the transmission system more complex in terms of adaptation / installation & maintenance of this apparatus. The system requires high skilled person in case of any failures, also creates problem for the fimctioning even in case of small failure in the system. Apart from above things the apparatus is costlier, which ultimately reflecting to increase product cost.
Therefore it's a long standing need of the vehicle manufactures to have a simpler, compact, flexible and mechanically operated forward / reverse changeover assembly unit, which will help to produce equal number of reverse speeds that of available forward speeds. The said assembly unit can be easily adopted and / or implemented in the said existing transmission system with least modification. Therefore reduces necessity to design new transmission system and related vehicle components for achieving equal number of vehicle output speeds both in forward and reverse direction, minimize development time and cost. Also changeover for the equal number of reverse speed that of available forward speeds at old customer end will be cost effective.
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Summary of the Invention :
The prime objective of this Invention is to provide a simpler, compact, flexible and mechanically operated Forward / Reverse changeover assembly unit, which can be easily installed and / or adapted at suitable location in the transmission system of a vehicle(s) like tractor(s) or similar vehicle(s), thereby increases serviceability.
Another objective of this Invention is to provide a means of a Forward / Reverse changeover assembly unit in the existing transmission system of a vehicle for producing equal number of reverse speeds that of available forward speeds, thereby minimizing development time and cost by avoiding re-designing of existing transmission system.
Another aspect of this invention is to provide a modular design, which will be added advantage to old customer, who wants to changeover for equal number of forward and reverse vehicle output speeds.
Brief description Of the Drawings :
Figure 1 shows one of the transmission system layout for achieving equal number of forward and reverse speeds with neutral position by using means of forward / reverse changeover assembly unit.
Figure 2 shows the detail view of the forward / reverse changeover assembly unit along with the shifting mechanism.
Detailed descriptions of the preferred embodiments :
As shown in figure 1 and 2 a forward / reverse changeover assembly unit is provided at suitable location in the transmission system of an off-highway vehicle(s) like tractor(s) or similar vehicle(s) to achieve equal number of vehicle output speeds both in forward and reverse direction with neutral position, wherein
a housing (6) covering whole forward / reverse changeover mechanism is positioned in between engine (1) & main speed changeover mechanism (16) or in between main speed
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changeover mechanism (16) & auxiliary speed changeover mechanism (not shown) or alike location in a transmission system of a vehicle. The power from the engine (1) through clutch assembly (4) mounted on the engine Flywheel (3) is supplied to the input shaft (5). The said input shaft (5) is journalized in a said housing (6) of forward / reverse assembly unit and interlocked with the coupling (8). The said coupling (8) transversally meshes either with the input gear (7), which is rotating freely on said input shaft (5) or output gear (9), which is interlocked with output shaft (14) or remains in a neutral position on input shaft (5). The input gear (7) in turn meshes with a free rotating idler gear (10) rotatably mounted on reverse gear train idler shaft (12). The idler gear (10) in turn meshes with cluster gear (11 or 13), mounted on another shaft (15) of said reverse gear train. The other cluster gear (11 or 13) meshes with the output gear (9). The shifting of the coupling (8) is done through the direction control lever (21), provided near by operator's seat (18). The directional control lever (21) is linked to the coupling (8) by means of mechanical shifting components like fork (19), rail (20).
To achieving forward speeds of the vehicle, operator moves the direction control lever (21) towards front with respect to the operator's seat (18) causing the coupling (8) to engage with the output gear (9). In this condition the power coming from engine (1) through input drive shaft (5) is transmitted directly through the coupling (8) to the output gear (9). Since the output gear (9) is interlocked with output drive shaft (14), which fiirther transmits the drive to the rear and / or front wheels of the vehicle through further vehicle transmission system (Speed changeover mechanism (16), auxiliary changeover mechanism (not shown), differential mechanism (17) and like transmitting mechanisms), thus resulting forward movement of the. vehicle.
To achieve reverse speeds of the vehicle, operator moves the direction control level (21) towards rear with respect to the operator's seat (18) causing the coupling (8) to engage with the input gear (7). In this condition the power coming from the engine (1) through the input drive shaft (5) is transmitted through the coupling (8) to the input gear (7). The input gear (7) in turn drives the free rotating idler gear (10), which in turn drives the cluster gear (11 or 13) mounted on shaft (15) of reverse gear train. The cluster gear (11 or 13) fiirther transmits
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drive to the output gear (9), which is interlocked on output shaft (14). The drive from output drive shaft (14), is further transmitted to the rear and / or front wheels of a vehicle through fiirther transmission system (Speed changeover mechanism (16), auxiliary changeover mechanism (not shown), differential mechanism (17) and alike transmitting mechanisms) , thus resulting reverse movement of the vehicle.
When the operator maintains the direction control lever (21) in neutral (centre) position, the coupling (8) also remains in neutral position causing power neither transmits to input gear (7) nor output gear (9), thus keeping the vehicle in neutral position.
Hence the forward and reverse speeds of the vehicle with neutral position is achieved by providing a forward / reverse changeover assembly unit at a suitable location in the transmission system of an off-highway vehicle like tractor(s) or similar vehicle(s).
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We Claim:
1. A forward / reverse changeover assembly unit for a transmission system of off-
highway vehiclefs] like tractor[s] or similar vehicle[s] comprising of:
- a means of housing [6] covering shafts, gears, bearings, coupling and / or similar transmission system components;
- an input shaft [5] journalized in a said housing [6] to transmit power from input source to output shaft [14];.
- an input gear [7] rotatably mounted on said input shaft [5] and in turn meshes with a free rotating idler gear [10] of reverse gear train;
- said reverse gear train is a part of said assembly unit and located in said housing on either side of said input and output gear [9];
- said output gear [9] of said assembly unit is interlocked with said output shaft and in turn meshes with one of the cluster gear [11 or 13] of said reverse gear train;
- a means of coupling [8] is interlocked with said input shaft and either engages with said input / output gear or remains in a neutral position.
2. The assembly unit as claimed in claim 1 wherein reverse gear train of said assembly
unit comprises of:
- free rotating idler gear [10 ] rotatably mounted on a idler shaft [12 ] of said reverse gear train & connects said input gear [7] and one of the cluster gear [11 or 13];
- said idler shaft [12 ] is located at it's both the ends in a said housing [6];
- said cluster gear [11 or 13] rotatably mounted on another shaft [15] of a said reverse
gear train and one of it's gear driven by said free rotating idler gear [10 ];
- said another shaft [15 ] of said reverse gear train is also located at it's both the ends
in a said housing [6 ].
3. The assembly unit as claimed in claim 1 wherein, said forward / reserve changeover
assembly unit is positioned in between engine [1] & main speed changeover
mechanism [16] or in between said main speed changeover mechanism & auxiliary
speed changeover mechanism or alike location in a transmission system of a
vehicle(s) like tractor(s) or similar vehicle(s) to produce equal number of speeds both
in forward and reverse direction with neutral position.
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4. A forward / reverse changeover assembly unit as claimed in claim 1 , wherein forward direction of said output shaft [14 ] is achieved by transversally engaging said coupling [8] with said output gear [9 ] of said assembly unit, therefore power from said input shaft [5] is transferred to said output shaft [14] in forward direction while flowing from said input shaft [5] through said coupling [8] and said output gear [9] to said output shaft [14].
5. A forward / reverse changeover assembly unit as claimed in claim 1 , wherein reverse direction of said output shaft [14] is achieved by transversally engaging said coupling [8] to said input gear [7] of said assembly unit, therefore power from said input shaft [5] is transferred to said output shaft [14] in reverse direction while flowing from said input shaft [5] through said coupling[8], said input gear[7], said reverse gear train and said output gear [9]to said output shaft [14].
6. A forward / reverse changeover assembly unit as claimed in claim 1, wherein neutral position of said output shaft [14] in achieved without shifting said coupling [8] either towards said input gear [7] or said output gear [9] of said assembly unit.
7. A forward / reverse changeover unit wherein the shifting of the coupling [8] as claimed in claim 1, 4 and 5 is done by means of a direction control lever[21] provided near the operator's seat [18] wherein direction control lever [21], operating at three different positions, is linked to the coupling [8] by means of mechanical shifting components like fork [19], rail [20] thereby achieving forward, reverse direction and neutral position.
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8. A forward / reverse changeover assembly unit as claimed in claim 1, wherein said output shaft [14] is operatively connected to rear and / or front wheels through the further transmission mechanisms [16, 17] of said vehicle transmitting system to achieve equal number of forward / reverse vehicle output speeds with neutral position.
Dated this 16th day of June 2004


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SHY^M^UNDER IYER PATENT AGENT
TO,
THE CONTROLLER OF PATENTS, THE PATENT OFFICE AT MUMBAI.