Description:TECHNICAL FIELD
[001] The embodiments herein generally relate to transmission shift mechanisms in vehicles and more, particularly to a system for centralizing a gear shift lever in a power transmission unit of the vehicle.
BACKGROUND
[002] Generally, a gear shift mechanism is used in a manual transmission of a vehicle for selecting respective gears which are required for various driving conditions of the vehicle. Typically, the gear shift mechanism includes a gear shift assembly, a plurality of shift rails, a plurality of shift forks, a plurality of shift bushes and a plurality of shift sleeves/ synchronizers. The gear shift assembly permits a vehicle operator to selectively shift between various forward ratio gears and a reverse gear. The gear shift assembly includes a tower housing secured to an exterior surface of the transmission casing and a gear shift lever that is operably coupled to a socket and shift rail in the transmission. Typically, the gear shift assembly has a standard shift pattern such that the gear shift lever is movable along a neutral cross-over path to a plurality of preselected gate positions. Each gate position defines a linear shift plane for a pair of ratio gears. Most commonly, the gate position located at one end of the neutral cross-over path defines the linear shift plane between the first and second forward gears, or the 1-2 shift plane, the gate position located in the center of the neutral cross-over path defines the shift plane between the third and fourth forward gears, or the 3-4 shift plane, and the gate position at the opposite end of the neutral cross-over path defines a shift plane between the fifth forward ratio gear and the reverse gear position, or the 5-R shift plane.
[003] Gear shift levers incorporate various mechanisms to positively position the shift lever in a desired position. For example, a spring member may be operably connected to the gear shift lever of the gear shift tower assembly to bias the shift lever. As such, the spring mechanism generates a return force that acts directly on the shift lever for biasing the shift lever to a center position. However, gear shift assemblies of this type have proven to be difficult to provide a smoothly operating mechanism or to provide a substantially constant centering force.
[004] Therefore, there exists a need for a system for centralizing a gear shift lever in the power transmission unit of the vehicle, which obviates the aforementioned drawbacks.
OBJECTS
[005] The principal object of embodiments herein is to provide a system for centralizing a gear shift lever in a power transmission unit of the vehicle.
[006] Another object of embodiments herein is to provide the system that consumes less packaging space and allows easier serviceability of the power transmission unit.
[007] Another object of embodiments herein is to provide the system that is adapted for automatically centralizing the gear shift lever in a 3 gate gear shift plane configuration.
[008] Another object of embodiments herein is to provide a shift lever centralizing pin which facilitates multiple functions thereby eliminating need of sperate parts.
[009] Another object of embodiments herein is to provide the system which provides constant centering force to a gear shift lever in center position (neutral).
[0010] Another object of embodiments herein is to provide the system which is reliable and inexpensive.
[0011] These and other objects of embodiments herein will be better appreciated and understood when considered in conjunction with following description and accompanying drawings. It should be understood, however, that the following descriptions, while indicating embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF DRAWINGS
[0012] The embodiments are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0013] Fig. 1 depicts a cross-sectional view showing a system for centralizing a gear shift lever in a power transmission unit of a vehicle, where the gear shift lever is in a neutral position, according to embodiments as disclosed herein;
[0014] Fig. 2 depicts an exploded view showing the system for centralizing the gear shift lever, according to embodiments as disclosed herein;
[0015] Fig. 3 depicts a cross-sectional view showing the gear shift lever in a first and reverse gate engaged position, according to embodiments as disclosed herein; and
[0016] Fig. 4 depicts a cross-sectional view showing the gear shift lever in a fourth gate engaged position, according to embodiments as disclosed herein.
DETAILED DESCRIPTION
[0017] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0018] The embodiments herein achieve a system for centralizing a gear shift lever in a power transmission unit of the vehicle. Referring now to the Figs. 1 through 4, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0019] Fig. 1 depicts a cross-sectional view showing a system (100) for centralizing a gear shift lever (10) in a power transmission unit of a vehicle, where the gear shift lever (10) is in a neutral position, according to embodiments as disclosed herein. In an embodiment, the system (100) includes a plurality of centralizing poppet pins (102), a plurality of centralizing springs (104), a plurality of spring retainers (106) and a shift lever centralizing pin (108). For the purpose of this description and ease of understanding, the system (100) is explained herein with below reference to centralizing a gear shift lever (10) in a power transmission unit of an agricultural vehicle such as a tractor. However, it is also within the scope of the invention to use/practice the system (100) for centralizing the gear shift lever in any other power transmission unit of any other agricultural machines or any other off-road vehicles or any other vehicles without otherwise deterring the intended function of the system (100) as can be deduced from the description and corresponding drawings.
[0020] Each centralizing spring (104) is disposed between corresponding spring retainer (106) and corresponding centralizing poppet pin (102). One end of each centralizing spring (104) is engaged with corresponding spring retainer (106) and another end of each centralizing spring (104) is engaged with a retaining collar (102C) (as shown in fig. 1) defined on corresponding centralizing poppet pin (102). The plurality of spring retainers (106) are connected to a transmission structure (20). For the purpose of this description and ease of understanding, the transmission structure (20) is considered to be a transmission top cover. Each spring retainer (106) defines a spring receiving portion (106S) (as shown in fig. 2) adapted to receive at least a portion of corresponding centralizing spring (104) therein. For the purpose of this description and ease of understanding, the spring receiving portion (106S) is considered to be a cavity. The transmission structure (20) defines a plurality of openings (20P) (as shown in fig. 1). Each opening (20P) is adapted to receive corresponding centralizing spring (104) and corresponding centralizing poppet pin (102) therein. A portion of each spring retainer (106) is removably connected to corresponding opening (20P) of the transmission structure (20) therein to retain corresponding the centralizing spring (104) and the corresponding centralizing poppet pin (102) thereon. Each spring retainer (106) is considered to be a bolt.
[0021] The shift lever centralizing pin (108) is transversely inserted into a shift lever fulcrum ball (30) and the gear shift lever (10) in which the shift lever centralizing pin (108) extends out from both sides of the shift lever fulcrum ball (30). The shift lever centralizing pin (108) is adapted to facilitate centralizing of the gear shift lever (10) and restricts rotation of the gear shift lever (10) about its axis. Further, the shift lever centralizing pin (108) is adapted to connect the gear shift lever (10) with the shift lever fulcrum ball (30). Each centralizing spring (104) is adapted to push corresponding centralizing poppet pin (102) against corresponding end of the shift lever centralizing pin (108) thereby automatically moving (self-centering) the gear shift lever (10) to center position (neutral) in a neutral shift plane upon moving the gear shift lever (10) away from the neutral position and also while releasing/dis-engaging the gear shift lever (10) from any gear position by the operator (driver) of the vehicle for the purpose of bringing the vehicle to neutral. For the purpose of this description and ease of understanding, each centralizing spring (104) is considered to be a helical spring. However, it is also within the scope of the invention to use any other types of springs as centralizing spring (104) without otherwise deterring the intended function of the centralizing spring (104) as can be deduced from the description and corresponding drawings. Each centralizing poppet pin (102) is transverse to said shift lever centralizing pin (108) when the gear shift lever (10) is in the center position (neutral position).
[0022] The technical advantages of the system (100) are as follows. The system (100) consumes less packaging space and allows easier serviceability of the power transmission unit. The system is adapted for automatically centralizing the gear shift lever in a 3 gate gear shift plane configuration. The shift lever centralizing pin facilitates multiple functions such as centralization of the gear shift lever, holding of the gear shift lever and the shift lever fulcrum ball, and restricts rotation of the gear shift lever about its axis, thus eliminating need of sperate parts to perform the multiple functions of the shift lever centralizing pin. The system is reliable and inexpensive. The system provides constant centering force to a gear shift lever in center position (neutral).
[0023] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modifications within the spirit and scope of the embodiments as described herein.
, Claims:We claim:
1. A system (100) for centralizing a gear shift lever (10) in a power transmission unit of a vehicle, said system (100) comprising:
a plurality of spring retainers (106) connected to a transmission structure (20);
a plurality of centralizing poppet pins (102);
a plurality of centralizing springs (104), wherein each of said centralizing spring (104) is disposed between corresponding said spring retainer (106) and corresponding said centralizing poppet pin (102); and
a shift lever centralizing pin (108) transversely inserted into a shift lever fulcrum ball (30) and said gear shift lever (10) in which said shift lever centralizing pin (108) extends out from both sides of said shift lever fulcrum ball (30).
2. The system (100) as claimed in claim 1, wherein each of said centralizing spring (104) is adapted to push corresponding said centralizing poppet pin (102) against corresponding end of said shift lever centralizing pin (30) thereby automatically moving said gear shift lever (10) to a center position (neutral).
3. The system (100) as claimed in claim 1, wherein one end of each of said centralizing spring (104) is engaged with corresponding said spring retainer (106) and another end of each of said centralizing spring (104) is engaged with a retaining collar (102C) defined on corresponding said centralizing poppet pin (102).
4. The system (100) as claimed in claim 3, wherein each of said spring retainer (106) defines a spring receiving portion (106S) adapted to receive at least a portion of corresponding said centralizing spring (104) therein; and
said spring receiving portion (106S) is at least a cavity.
5. The system (100) as claimed in claim 4, wherein said transmission structure (20) defines a plurality of openings (20P), wherein each of said opening (20P) is adapted to receive corresponding said centralizing spring (104) and said corresponding said centralizing poppet pin (102) therein.
6. The system (100) as claimed in claim 5, wherein a portion of each of said spring retainer (106) is removably connected to corresponding opening (20P) of said transmission structure (20) therein to retain corresponding said centralizing spring (104) and said corresponding said centralizing poppet pin (102) thereon;
each of said spring retainer (106) is a bolt; and
said transmission structure (20) is a transmission top cover.
7. The system (100) as claimed in claim 2, wherein each of said centralizing poppet pins (102) is transverse to said shift lever centralizing pin (108) when said gear shift lever (10) is in the center position (neutral position).
8. The system (100) as claimed in claim 1, said shift lever centralizing pin (108) is adapted to connect said gear shift lever (10) with said shift lever fulcrum ball (30) and restricts rotation of said gear shift lever (10) about its axis; and
said shift lever centralizing pin (108) is adapted to facilitate centralizing of said gear shift lever (10).
9. The system (100) as claimed in claim 1, wherein each of said centralizing spring (104) is at least a helical spring.