TECHNICAL FIELD

[0001] The present subject matter relates, in general, to a gear shift system and, particularly but not exclusively, to a gear shift system in fanning vehicles.

BACKGROUND

[0002] Farming vehicles, such as tractors and harvesters, are required to have substantially high horsepower for the purposes of performing a variety of farming operations. Such requirements have been typically met by development of farming vehicles which have substantially powerful engines and substantially bigger transmission systems. A powerful farming vehicle may have a transmission system with a gear box having a large number of gears. One or more operating levers, coupled to the gear box, may be provided in the farming vehicle, which a driver may operate to selectively shift between the gears for controlling the speed of the farming vehicle.

[0003] The operating levers, in addition to other controls, such as a steering and brake pedals, are typically provided in a driver cabin of the farming vehicle. The substantially powerful engine and the substantially bigger transmission system may generate lot of vibrations and noise in the farming vehicle. The driver cabin is usually located on the top of the farming vehicles to facilitate the farming operations. Also, for the farming vehicles, such as the harvester, in which the harvesting equipment is mounted on top of vehicle, the transaxle is isolated from the driver cabin. Thus, in such type of farming vehicles, among other controls, the operating levers, which are coupled to the gear box of the transmission system, are at a place remote from the transmission system.

SUMMARY

[0004] This summary is provided to introduce concepts related to a gear shift system in farming vehicles and these concepts are further described below in the detailed description. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.

[0005] In accordance with an embodiment of the present subject matter a gear shift system in a farming vehicle is described. The gear shift system comprises a lever assembly with a main gear shift lever, a gear box with a main gear shift arm projecting upwardly from the gear box, and a plurality of push-pull cable to couple the main gear shift lever and the main gear shift arm for main gear shifting. The plurality of push-pull cable comprises a first push-pull cable and a second push-pull cable. The first push-pull cable is coupled to the main gear shift lever at one end by a first joint and to the main gear shift arm at other end by a second joint such that the main gear shift arm is movable along a first linear direction for gate selection. Further, the second push-pull cable is coupled to the main gear shift lever at one end by the first joint and to the main gear shift arm at other end by a third joint such that the main gear shift arm is movable along a second linear direction for the main gear shifting.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of the method(s) in accordance with the present subject matter are described, by way of example only, and with reference to the accompanying figures, in which:

[0007] Figure 1 illustrates a gear shift system, in accordance with an embodiment of the present subject matter.

[0008] Figure 2 illustrates coupling of push-pull cables to a gear box, in accordance with an embodiment of the present subject matter.

[0009] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of gear shift systems embodying the principles of the present subject matter.

DETAILED DESCRIPTION

[0010] The present subject matter relates to a gear shift system in a farming vehicle. The gear shift system of the present subject matter facilitates in substantially smooth and easy gear shifting in a farming vehicle where operating levers of the gear shift systems are provided in a driver cabin isolated from transaxle of the farming vehicle.

[0011] In a conventional gear shift system, operating levers provided in the driver cabin are coupled to a gear box of the farming vehicle through various mechanical linkages for shifting of gears of the gear box. For example, the operating levers may be coupled to the gears of the gear box by rods connected to each other through mechanical joints. The force applied on the operating levers is transmitted to the gear box through the rods for the gear shifting. With the mechanical linkages between the operating levers and the gear box, all the applied force is not transmitted to the gear box. A part of the applied force is lost during the operation of the mechanical linkages.

[0012] In the conventional gear shift system, the gear shifting is not smooth due to the mechanical linkages. With the mechanical linkages between the operating levers and the gear box, the driver may not feel the gear shifting completely. With this, the driver may not be able to confirm whether the gear shifting is complete or partial. In case the gear shifting is partial, gears in the gear box may get damaged.

[0013] Also, with the mechanical linkages, the conventional gear shift system experiences substantially large vibrations. Such vibrations are transferred to the joints, such as ball joints, used in the mechanical linkages, and components, such as forks, adjacent to the gear box, which cause substantial wear and tear, and energy loss in the gear shift system. Further, the mechanical linkages are complex in arrangement and typically incorporate a large number of components. The mechanical linkages may also require regular maintenance, such as continuous oiling of joints, which may increase cost of operating the farming vehicle over a long run.

[0014] The present subject matter discloses a gear shift system in a farming vehicle. The farming vehicle may be a tractor, a harvester, a combined harvester, and the like, in which the driver cabin is isolated from transaxle of the vehicle. The gear shift system with eight forward gears and eight reverse gears is described, in accordance with an implementation of the present subject matter. The gear shift system may be also implemented in gear boxes with different number of gears without deviating from scope of the invention.

[0015] The gear shift system of the present subject matter includes a lever assembly, a gear box, and push-pull cables to couple the lever assembly and the gear box for the shifting of gears of the gear box. The lever assembly is installed in the driver cabin of the farming vehicle and may include a main gear shift lever, a high-low speed gear shift lever, and a forward-reverse direction gear shift lever.

[0016] The main gear shift lever is used for main gear shifting. For example, the main gear shift lever may be used for the gear shifting to one of first gear, second gear, third gear, and fourth gear. For the purpose of gear shifting, a gate selection is performed with the help of the main gear shift lever depending on the gear number being selected. For the gate selection, the driver may move the main gear shift lever either to the left or to the right. In an example, for shifting the gear to the first or the second gear, the driver may move the main gear shift lever to the left, and for shifting the gear to the third or the fourth gear, the driver may move the main gear shift lever to the right. After the gate selection, the desired gear may be selected by moving the main gear shift lever either to the forward direction or to the backward direction.

[0017] Similarly, the high-low speed gear shift lever is used for high-low speed gear shifting, i.e., the gear shifting to the high speed gear or to the low speed gear, in the farming vehicle. In an example, for shifting the gear to the low speed gear, the high-low speed gear shift lever is moved in the backward direction, and for shifting the gear to the high speed gear, the high-low speed gear shift lever is moved in the forward direction.

[0018] Similarly, the forward-reverse direction gear shift lever is used for forward-reverse direction gear shifting, i.e., the gear shifting to the forward direction gear or to the reverse direction gear, in the farming vehicle. In forward direction gear, the farming vehicle will move in a forward direction, and in reverse direction gear, the farming vehicle will move in a reverse direction. In an example, for shifting the gear to the forward direction gear, the forward-reverse speed gear shift lever is moved in the forward direction, and for shifting the gear to the reverse direction gear, the forward-reverse gear shift lever is moved in the backward direction.

[0019] In one implementation, the gear box used in the present subject matter may be a synchromesh gear box. The synchromesh gear box is well known in the art, therefore not described in the description. The gear box may include a main gear shift arm, a high-low speed arm, and a forward-reverse direction arm. In an implementation, all the arms may project upwardly from the gear box. The main gear shift arm is configured for moving main gear shift rails for engaging either of the main gears, from the first, the second, the third, and the fourth gear. Similarly, the high-low speed arm is configured for moving a high-low speed shift rail for engaging either the high speed gear or the low speed gear, and the forward-reverse direction gear arm is configured for moving a forward-reverse direction shift rail for engaging either the forward direction gear or the reverse direction gear.

[0020] Further, the push-pull cables are used for coupling the main gear shift lever, the high-low gear shift lever, and the forward-reverse gear shift lever of the lever assembly to the main gear shift arm, high-low speed gear shift arm, and the forward-reverse direction gear shift arm, respectively, of the gear box. With the push-pull cables coupled between the lever assembly and the gear box, vibrations on the operating levers and the force needed for gear shifting reduce substantially.

[0021] In one implementation, the main gear shift arm is coupled to the main gear shift lever of the lever assembly by a plurality of push-cables. The plurality of push-pull cables includes a first push cable and a second push-pull cable. Depending on the operation of the main gear shift lever by the driver, the first push-pull cable is configured to perform a push-pull action on the main gear shift arm such that the main gear shift arm moves along a first linear direction. The first linear direction may be a direction in which movement of the main gear shift arm is responsible for the gate selection. The first push-pull cable, at one end, is coupled to the main gear shift lever by a first joint and at other end, is coupled to the main gear shift arm of the gear box by a second joint. In an implementation, the first push-pull cable may be coupled to the main gear shift lever by a spider joint, and to the main gear shift arm by a guided pin joint.

[0022] Further, depending on the operation of the main gear shift lever by the driver, the second push-pull is configured to perform a push-pull action on the main gear shift arm such that the main gear shift arm moves along a second linear direction. The second linear direction may be a direction in which movement of the main gear shift arm is responsible for the main gear shifting, i.e., for the gear shifting to one of the main gears from the first to fourth gears of the gear box. In one implementation, the first linear direction and the second linear direction are substantially perpendicular to each other. The second push-pull cable, at one end, is coupled to the main gear shift lever by the first joint and to the main gear shift arm at other end by a third joint. In an implementation, the second push-pull cable may be coupled to the main gear shift lever by the spider joint and to the main gear shift arm by a ball joint.

[0023] Further, the high-low speed arm is coupled to the high-low speed gear shift lever by a third push-pull cable, and the forward-reverse direction gear arm is coupled to the forward-reverse direction arm of the gear box a fourth push-pull cable. Depending on the operation of the high-low speed gear shift lever by the driver, the third push-pull cable is configured to perform a push-pull action on the high-low speed gear shift arm such that the high-low speed gear shift arm moves for the high-low speed gear shifting, i.e., for the gear shifting to either the high speed gear or the low speed gear. Similarly, depending on the operation of the forward-reverse direction gear shift lever by the driver, the fourth push-pull cable is configured to perform a push-pull action on the forward-reverse direction gear shift arm such that the forward-reverse direction gear shift arm moves for the forward-reverse direction gear shifting, i.e., for the gear shifting to either the forward direction gear or the reverse direction gear.

[0024] The third push-pull cable is coupled to the high-low speed gear shift lever at one end by a fourth joint, and to the high-low speed gear arm at other end by a first clevis joint. In an implementation, the fourth joint may be a clevis joint or a ball joint. The fourth push-pull cable is coupled to the forward-reverse direction gear shift lever at one end by a fifth joint and to the high-low speed gear arm at other end by a second clevis joint. In an implementation, the fifth joint may be a clevis joint or a ball joint.

[0025] Use of the push-pull cables in the coupling between the lever assembly and the gear box of the type described herein facilitates in achieving a substantially smooth gear shifting with substantially reduced vibrations on the operating levers of the lever assembly. Also, with the gear shift system of the present subject matter, the driver of the farming vehicle can feel the gear shifting to substantially avoiding a possibility of partial gear shifting. Further, substantially less effort is required by the driver for the gear shifting, which provides comfort to the driver while shifting between various gears in the farming vehicle. This facilitates in substantially reducing the fatigue related problems that are typically caused to the driver. Furthermore, with the push-pull cables in the gear shift system, the loss of energy during the gear shifting and the wearing of the joints in the gear shift system are substantially less.

[0026] Although, the gear shift system of the present subject matter is described for a farming vehicle; however, in an implementation, the gear shift system of the present subject matter may be implemented in any vehicle in which the driver cabin is isolated from transaxle of the vehicle, albeit a few variations as understood to a person skilled in the art.

[0027] These and other advantages of the present subject matter would be described in a greater detail in conjunction with the following figures. It should be noted that the description and figures merely illustrate the principles of the present subject matter.

[0028] Figure 1 illustrates a gear shift system 100, in accordance with an embodiment of the present subject matter. Figure 1 shows the gear shift system 100 for gear shifting of eight forward and eight reverse gears. The gear shift system 100 includes a lever assembly with three levers, i.e., a main gear shift lever 102-1, a high-low speed gear shift lever 102-2, and a forward-reverse direction gear shift lever 102-3. Hereinafter, the main gear shift lever 102-1, the high-low speed gear shift lever 102-2, and the forward-reverse direction gear shift lever 102-3 may be collectively referred to as the operating levers 102, and individually referred to as the operating lever 102. Each of the operating levers 102 may have a knob on the top end, as shown in Figure 1, which the driver may grip to operate the operating levers 102 for the gear shifting.

[0029] In an implementation, the knobs may have gear shift patterns inscribed on them to assist the driver about the gear shifting. The gear shift patterns depict movements of the operating levers 102 for the gear shifting. For example, the knob on the main gear shift lever 102-1 may have an H pattern for the main gear shifting. The driver can move the main gear shift lever 102-1 in directions depicted by the H pattern for the main gear shifting.

[0030] The main gear shift lever 102-1 is used for main gear shifting in the farming vehicle. For example, the main gear shifting may include shifting to one of the first gear, the second gear, the third gear, and the fourth gear. Initially, the driver may move the main gear shift lever 102-1 in a direction indicated on the knob for the gate selection. In an example, if the main gear shift lever 102-1 is moved to the left side from a neutral position of the main gear shift lever 102-1, the gate selection is for the first gear and the second gear. Similarly, if the main gear shift lever 102-1 is moved to the right side from the neutral position of the
main gear shift lever 102-1, the gate selection happens for the third gear and the fourth gear.

[0031] After the gate selection, the driver may further move the main gear shift lever 102-1 in a direction depending on the selection of gear in the main gear shifting. In one implementation, after the gate selection, the driver may move the main gear shift lever 102-1 in a forward (front) direction or in a backward (rear) direction for the gear shifting to the desired gear. For example, after the gate selection, the main gear shift lever 102-1 may be moved to the forward direction for the selection of the first gear, and the main gear shift lever 102-1 may be moved to the backward direction for the selection of the second gear. Similarly, the gear main shifting of the third and the fourth gear may be performed after the gate selection.

[0032] Further, the high-low speed gear shift lever 102-2 is used for selection between high speed gear and low speed gear depending on the operating speed of the farming vehicle. The low speed gear is configured such that, with the low speed gear engaged, the farming vehicle can attain up to a predefined speed. To attain speed above the predefined speed, the high speed gear may be engaged. It may be understood that with either of the low speed or the high speed gear engaged, the main gears, from the first, the second, the third, and the fourth gear, can be selected for further controlling the speeds of the farming vehicle below and above the predefined speed. In one implementation, the driver may move the high-low speed gear shift lever 102-2 in a forward (front) direction and in a backward (rear) direction for the gear shifting to the high speed gear and the low speed gear, respectively.

[0033] Further, the forward-reverse direction gear shift lever 102-3 is used for driving the farming vehicle in a forward direction or in a reverse direction. In one implementation, the driver may move the forward-reverse direction gear shift lever 102-3 in a forward (front) direction or in a backward (rear) direction for the gear shifting to the forward direction gear and the reverse direction gear, respectively.

[0034] The main gear shift lever 102-1, the high-low speed gear shift lever 102-2, and the forward-reverse direction gear shift 102-3 collectively allow the driver to perform the gear shifting and drive the farming vehicle in eight forward gears and eight reverse gears. The eight forward gears and the eight reverse gears are summarized as:

Forward gears 4 main gears Low speed gear —>
(first, second, third, fourth gear)

4 main gears High speed gear —►
(first, second, third, fourth gear)

Reverse gears 4 main gears Low speed gear —►
(first, second, third, fourth gear)

4 main gears High speed gear —»
(first, second, third, fourth gear)

[0035] In one implementation, the gear shift system 100 further comprises a gear box 104 coupled to the operating levers 102 of the lever assembly. In one implementation, the gear box 104 may be a synchromesh gear box with the eight forward gears and eight reverse gears, as described above. The gear box 104 includes a main gear shift arm 104-1, a high-low speed gear shift 104-2, and a forward-reverse direction gear shift arm 104-3. The main gear shift arm 104-1 is movable along a first linear direction and a second linear direction for the engagement of one of the four main gears. The first linear direction and the second linear direction are substantially perpendicular to each other. The main gear shift arm 104-1 is further coupled to main gear shift rails onto which various gears, including the four main gears, are mounted. When one of the main gear shift rails is moved in a particular direction by the main gear shift arm 104-1, the main gear shifting is performed. The main gear shifting is further described in detail later in the description.

[0036] Similarly, the high-low speed gear shift arm 104-2 is movable such that it may engage one of the low speed and the high speed gears mounted on a high-low speed gear shift rail. This allows the driver to drive the farming vehicle in different speeds below and above a predefined speed. Further, the forward-reverse direction gear shift arm 104-3 is movable such that it may engage one of the forward direction and the reverse direction gears mounted on a forward-reverse direction gear shift rail. With this, the farming vehicle can move in the forward direction and the reverse direction.

[0037] Further, as shown Figure 1, the main gear shift lever 102-1 is coupled to the gear box 104 by a plurality of cables comprising a first push-pull cable 106-1 and a second push-pull cable 106-2. The high-low speed gear shift lever 102-2 is coupled to the gear box 104 by a third push cable 106-3, and the forward-reverse direction gear shift lever 102-3 lever is coupled to the gear box 104 by a fourth push-pull cable 106-4. The first push-pull cable 106-1, the second push-pull cable 106-2, the third push-pull cable 106-3, and the fourth push-pull cable 106-4 hereinafter collectively may be referred to as the push-pull cables 106 and individual referred to as the push-pull cable 106.

[0038] In one implementation, the push-pull cables 106 may be also referred to Bowden cables. The push-pull cables 106 are helical wires covered with an outer sheath for protection purposes. The push-pull cables 106 enable in transferring a force, from one end to the other end, to cause a pull or a push action.

[0039] In one implementation, the main gear shift lever 102-1 is coupled to the main gear shift arm 104-1 of the gear box 104 by the first push-pull cable 106-1 and the second push-pull cable 106-2. The first push-pull cable 106-1, at one end, is coupled to the main gear shift lever 102-1 by a first joint 108 and to the main gear shift arm 104-1 by a second joint 110 such that the main gear shift arm 104-1 is movable along the first linear direction. The first push-pull cable 106-1 is configured to move the main gear shift arm 104-1 in the first linear direction for the gate selection in the gear box 104, as described earlier. Further, the second push-pull cable 106-2 is configured to move the main gear shift arm 104-1 for engaging one of the four main gears, as described earlier. The second push-pull cable 106-2, at one end, is coupled to the main gear shift lever 102-1 by the first joint 108 and to the main gear shift arm 104-1 at other end by a third joint 112 such that the main gear shift arm 104-1 is movable along the second linear direction for the main gear shifting. In an implementation, the first joint 108 may be a spider joint, the second joint 110 may be guided pin joint, and the third joint 112 may be ball joint. Couplings of the push-pull cables 106 at the main gear shift arm 104-1 and the operation of the main gear shift arm 104-1 by the push-pull cables 106 are explained in more details later in the description with reference to Figure 2.

[0040] In one implementation, the high-low speed gear shift lever 102-2 is coupled to the high-low speed gear arm 104-2 by the third push-pull cable 106-3. One end of the third push-pull cable 106-3 is coupled to the high-low speed gear shift lever 102-2 by a fourth joint 114 and other end of the third push-pull cable 106-3 is coupled to the high-low speed gear shift arm 104-2 by a first clevis joint 116. In an example, the fourth joint 114 may be a clevis joint or a ball joint. The operation of the high-low speed gear shift arm 104-2 by the push-pull cable 106 is explained in more detail later in the description with reference to Figure 2.

[0041] In one implementation, the forward-reverse direction gear shift lever 102-3 is coupled to the forward-reverse direction shift gear arm 104-3 by the fourth push-pull cable 106-4. The fourth push-pull cable 106-4 is coupled to the forward-reverse direction gear shift lever 102-3 at one end by a fifth joint 118 and to the forward-reverse direction gear shift arm 104-3 at other end by a second clevis joint 120. In an example, the fifth joint 118 may be a clevis joint or a ball joint. The operation of the forward-reverse direction gear shift arm 104-3 by the push-pull cable 106 is explained in more detail later in the description with reference to Figure 2.

[0042] Figure 2 illustrates coupling of the push-pull cables 106 to the gear box 104, in accordance with an embodiment of the present subject matter. Figure 2 shows mounting brackets 202-1 and 202-2 supporting the push-pull cables 106 which are coupled to the gear box 104. The first push-pull cable 106-1 is coupled to the main gear shift arm 104-1 by the second joint 110 through an L-bracket 204. In one implementation, for the main gear shifting to one of the four main gears, for example, the first gear or the second gear, the main gear shift lever 102-1 (not shown in Figure 2) is moved, by the driver, to the left side from the neutral position of the main gear shift lever 102-1. This movement of the main gear shift lever 102-1 causes a pull action on the first push-pull cable 106-1. The pull action on the first push-pull cable 106-1 moves (pulls) the main gear shift arm 104-1 along the first linear direction to perform the gate selection for the engagement of the first gear or the second gear. After this, the main gear shift lever 102-1 may be moved either to the forward direction or to the backward direction, depending on whether to engage the first gear or the second gear, respectively. The movement of the main gear shift lever 102-1 in the forward direction causes a push action on the second push-pull cable 106-2. This push action pushes the main gear shift arm 104-1 along the second linear direction for engaging the first gear mounted on the main gear shift rail (not shown) coupled to the main gear shift arm 104-1. On the other hand, the movement of the main gear shift lever 102-1 in the backward direction causes a pull action on the second push-pull cable 106-2, which in turn pulls the main gear shift arm 104-1 along the second linear direction for engaging the second gear mounted on the main gear shift rail.

[0043] Similarly, for the main gear shifting to the third gear or the fourth gear, the main gear shift lever 102-1 is moved, by the driver, to the right side from the neutral position of the main gear shift lever 102-1. This movement of the main gear shift lever 102-1 causes a push action on the first push-pull cable 106-1. The push action on the first push-pull cable 106-1 moves (pushes) the main gear shift arm 104-1 along the first linear direction to perform the gate selection for the engagement of the third gear or the fourth gear. After this, the main gear shift lever 102-1 may be moved either to the forward direction or to the backward direction, depending on whether to engage the third gear or the fourth gear, respectively. The movement of the main gear shift lever 102-1 in the forward direction causes a push action on the second push-pull cable 106-2 which pushes the main gear shift arm 104-1 along the second linear direction for engaging the third gear mounted on the main gear shift rail coupled to the main gear shift arm 104-1. On the other hand, the movement of the main gear shift lever 102-1 in the backward direction causes a pull action on the second push-pull cable 106-2, which in turn pulls the main gear shift arm 104-1 along the
second linear direction for engaging the fourth gear mounted on the main gear shift rail.

[0044] Further, for the high-low speed gear shifting to a low speed gear or to a high speed gear, the high-low speed gear shift lever 102-2 (not shown in Figure 2) may be moved, by the driver, in the forward direction or in the backward direction from the neutral position for selecting the high speed gear or the low speed gear, respectively. For example, if the high-low speed gear shift lever 102-2 is moved to the forward direction, the third push-pull cable 106-3 is pushed, which in turn pushes the high-low speed gear shift arm 102-2 for engaging the high speed gear mounted on the high-low speed gear shift rail (not shown). On the other hand, if the high-low speed gear shift lever 102-2 is moved to the backward direction, the third push-pull cable 106-3 is pulled, which in turn pulls the high-low speed gear shift arm 102-2 for engaging the low speed gear mounted on the high-low speed gear shift rail.

[0045] Similarly, for the forward-reverse direction gear shifting to a forward direction gear or to a reverse direction gear, the forward-reverse direction gear shift lever 102-3 (not shown in Figure 2) may be moved, by the driver, in the forward direction or in the reverse direction from the neutral position for engaging the forward direction gear or the reverse direction gear, respectively. For example, if the forward-reverse direction gear shift lever 102-3 is moved to the forward direction, the fourth push-pull cable 106-4 is pushed, which in turn pushes the forward-reverse direction gear shift arm 102-2 for engaging the forward direction gear mounted on the forward-reverse direction gear shift rail (not shown) for driving the farming vehicle in the forward direction. On the other hand, if the forward-reverse direction gear shift lever 102-3 is moved to the backward direction, the fourth push-pull cable 106-4 is pulled, which in turn pulls the forward-reverse direction gear shift arm 102-2 for engaging the reverse direction gear mounted on the forward-reverse direction gear shift rail for driving the farming vehicle in the reverse direction.

[0046] Therefore, the gear shift system 100 facilitates the gear shifting of eight forward and eight reverse gears, i.e., four main gears in high speed gear and four main gears in low speed gear in the forward direction gear; and four main gears in high speed gear and four main gears in low speed gear in the reverse direction gear.

[0047] Although the figures and description herein is provided for the gear shift system 100 for eight forward gears and eight reverse gears with three levers, i.e., the main gear shift lever 102-1, the high-low speed gear shift lever 102-2, and the forward-reverse direction shift gear lever; the gear shift system 100 may have different number of levers for the gear shifting depending upon type of the gear box 104, albeit with a few variations, as will be understood by a person skilled in the art. In one embodiment of the present subject matter, the gear shift system 100 may have the main gear shift lever 102-1 and the forward-reverse direction gear shift lever 102-3 coupled to the main gear shift arm 104-1 and the forward-reverse direction gear shift arm 104-3 of a gear box, respectively, by one or more push-pull cables 106 for the gear shifting of four main gears in the forward direction and four main gears in the reverse direction, by the push-pull cables 106.

[0048] The push-pull cables 106 used for coupling the operating levers 102 and the gear box 104 of the gear shift system 100 facilitates a substantially smooth gear shifting in the farming vehicle with substantially reduced vibrations on the operating lever 102. The driver may experience less fatigue related problems while driving the farming vehicle which has the gear shift system 100 of the present subject matter. The gear shift system 100 allows the driver to feel the gear shifting which avoids the gear shifting related issues. For example, the driver can easily judge based on the gear shifting whether the gear shifting is partial or not. Further, energy to be transmitted to the gear box 104 is substantially fully
transmitted and there is substantially less or no loss of energy in the gear shift system 100 because of the push-pull cables 106. Further, with the gear shift system 100 of the preset subject matter, wear and tear of joints used in the gear shifting system 100 and in components adjacent to the gear box 104, such as a fork, is less. Also, with the push-pull cables 106 in the gear shift system 100, the joints may require a substantially less maintenance, which is beneficial in reducing the cost of running the farming vehicle.

[0049] Although embodiments for the gear shift system have been described in the language specific to structural features, it is to be understood that the invention is not necessarily limited to the specific features described. Rather, the specific features are disclosed and explained in the context of a few embodiments of the gear shift system.

[0050] Other advantages of the gear shift system will become better understood from the description and claim of an exemplary embodiment of the gear shift system. The gear shift system of the present subject matter is not restricted to the embodiments that are mentioned above in the description.

[0051] Although the subject matter has been described with reference to the specific embodiments, this description is not meant to be construed in limiting sense. Various modifications of the disclosed embodiments, as well as alternate embodiments of the subject matter, will become apparent to person skilled in the art upon reference to the description of the subject matter. It is therefore contemplated that such modifications can be made without departing from the spirit or the scope of the present subject matter as defined.

I/We claim:

1. A gear shift system (100) in a farming vehicle, the gear shift system (100) comprising:

a lever assembly comprising a main gear shift lever (102-1);

a gear box (104) comprising a main gear shift arm (104-1) projecting upwardly from the gear box (104); and

a plurality of push-pull cables to couple the main gear shift lever (102-1) to the main gear shift arm (104-1) for main gear shifting, wherein the plurality of push-pull cables comprises a first push-pull cable (106-1) and a second push-pull cable (106-2), and wherein

the first push-pull cable (106-1) is coupled to the main gear shift lever (102-1) at one end by a first joint (108) and to the main gear shift arm (104-1) by a second joint (110) such that the main gear shift arm (104-1) is movable along a first linear direction for gate selection; and

the second push-pull cable (106-2) is coupled to the main gear shift lever (102-1) at one end by the first joint (108) and to the main gear shift arm (104-1) at other end by a third joint (112) such that the main gear shift arm (104-1) is movable along a second linear direction for the main gear shifting.

2. The gear shift system (100) as claimed in claim 1, wherein the first linear direction and the second linear direction are substantially perpendicular to each other.

3. The gear shift system (100) as claimed in claim 1, wherein the first joint (108) is a spider joint.

4. The gear shift system (100) as claimed in claim 1, wherein the second joint (110) is a guided pin joint.

5. The gear shift system (100) as claimed in claim 1, wherein the third joint (112) is a ball joint.

6. The gear shift system (100) as claimed in claim 1, wherein the lever assembly further comprises a high-low speed gear shift lever (102-2);

the gear box (104) further comprises a high-low speed gear shift arm (104-2); and

the gear shift system (100) comprises a third push-pull cable (106-3) to couple the high-low speed gear shift lever (102-2) to the high-low speed gear shift arm (104-2) for high-low speed gear shifting.

7. The gear shift system (100) as claimed in claim 6, wherein the third push-pull cable (106-3) is coupled to the high-low speed gear shift lever (102-2) by a fourth joint (114) at one end and to the high/low speed gear shift arm (104-2) by a first clevis joint (116) at other end.

8. The gear shift system (100) as claimed in claim 1, wherein

the lever assembly further comprises a forward-reverse direction gear shift lever (102-3);

the gear box (104) further comprises a forward-reverse direction gear shift arm (104-3); and

the gear shift system (100) comprises a fourth push-pull cable (106-4) to couple the forward-reverse direction gear shift lever (102-3) to the forward-reverse direction gear shift arm (104-3) for forward-reverse gear shifting.

9. The gear shift system (100) as claimed in claim 8, wherein the fourth push-pull cable (106-4) is coupled to the forward-reverse direction gear shift lever (102-3) by a fifth joint (118) at one end and to the forward-reverse direction gear shift arm (104-3) by a second clevis joint (120) at other end.