FIELD OF THE INVENTION
The present invention generally relates to a gear shift assembly, and more
particularly to a twin rod gear shift assembly for manual transmission.
5 BACKGROUND OF THE INVENTION
Transmission shifters are well-known and are among the most important
components of automobile. Generally, there are three types of shifters which are
used in the vehicles i.e. Direct Shifters, Semi-remote Shifters and Remote
Shifters.
10
Typically, in direct shifters, a shift lever is directly connected on top of the
transmission with a detent lever and the movement of shift lever actuated by a
driver is directly transferred to the detent lever. Since, the shift lever is located
directly on top of the transmission, a precise gear shifting is achieved and this
15 improves the performance of the vehicle.
However, over the years there has been a lot of development in designing
of the vehicles. Most of the new age vehicles provides shift lever at a distance
from the transmission in order to provide usage of smaller engines and
20 transmission and packaging of the same away from the driver seat. Therefore,
such design requires linkage means such as a cable, a long and metallic curved
linkage bar, etc. in order to translate the movement of the shift lever to the detent
lever at the transmission. Usually, semi-remote shifter uses linkage (metal) bars
and remote shifter uses cables to connect the shift lever to the detent lever. The
25 challenge involved in such type of shifters is to provide precise and smooth gear
shifting operations, as many a times the shifting load is imprecise. Also, the
looseness feeling at knob is high due to multiple joints and the performance of the
vehicle is degraded by such imprecision, as well as it leads to undesired driving
conditions for the driver.
5
Figure 1 illustrates a gear shift assembly (100) employing a typical
semi-remote shifter, wherein a shift lever (102) is connected to a linkage rod (104).
Further, the linkage rod (104) is connected with a detent lever (not shown). In the
assembly, when a driver pushes the shift lever (102) in order to shift a gear, the
10 shift lever (102) translates the force to the linkage rod (104) which eventually
transfers the movement to the detent lever. However, in such a case the accurate
transfer of movement from shift lever (102) to the detent lever cannot be achieved
as substantive amount of the force has been observed at various joints in the
assembly.
15
The automobile industry has for many years searched for a reliable gear
shift system to replace the cumbersome maintenance of prone rod linkages
commonly used in remote and semi-remote shifters for translating shift lever
movement to the transmissionldetent lever.
20
It is thus desirable in many cases that some means are provided for
improving the location and operation of the shift stick mechanism. Fore, aft and
lateral movements of the gear actuating lever cause changes in the drive ratio of
the transmission when the shift stick is pivoted.
25
3
Furthermore, the mechanical characteristics of the apparatus are fixed
and the operational function may have a looseness or stiffness which is not
appropriate for all the drivers. Although some presently available apparatus
improve shift stick positioning, its feel and functionality are not universally
5 optimized by all due to primarily variations in driver strength and anatomical
characteristics. In high performance and racing vehicles it is known that shift stick
position and shift stick length have an influence on driver comfort, vehicle control
and shift time, and therefore directly affect driver endurance, lap times and safety.
10 The above-mentioned document and similar other prior arts talk about
gear shifter assemblies which translate movement of the shift lever to the detent
lever. However, the existing prior arts still do not provide a solution to the problem
of inaccurate transfer of movement, imprecision in gear shifting and poor
performance of the vehicle due to the looseness in the linkage rodslbars.
15
Therefore, it is desirable to have a gear shift assembly which overcomes
the aforesaid problems and shortcomings of the prior arts.
It is thus desirable that the tension or stiffness of the link between shift
20 stick and transmission suit the "feel" and control feedback requirements of the
driver. There is also a need for an improved remote shifter apparatus that is
selectively adjustable in various respects and can be easily retrofitted to an
automobile.
OBJECT OF THE INVENTION
Accordingly, it is an object of the present invention to provide a gear shift
assembly for manual transmission which precisely transfers the movement of the
shift lever to the detent lever. Further, the disclosed gear shift assembly for
5 manual transmission is easily removable, requires less maintenance and
enhances performance of the vehicle by improving "feel" and control feedback
requirements of the driver.
SUMMARY OF THE INVENTION
I 0 Embodiments of the present invention aim to provide a twin rod gear shift
assembly for manual transmission of a vehicle. The present invention eliminates
the need of complicated linkage rods to be installed between at least one shift
lever and at least one detent lever in case of remote andlor semi-remote gear
shifters. Further, performance of the vehicle has been enhanced by limiting the
15 looseness of the gear shift assembly by eliminating the need of the linkage rods
and their complicated child parts. Also, the proposed invention employs twin rods.
where each of the twin rods is connected with at least one shift lever and at least
one detent lever and precisely transfers the lateral and longitudinal movement of
at least one shift lever to at least one detent lever. Accurate transfer of the lateral
20 and longitudinal movement of at least one shift lever to at least one detent lever
provides the 'feel' of direct shifter to the driver, hence enhances the performance
of the driver. The twin rod gear shift assembly for manual transmission is provided
with the features of claim 1, however the invention may additionally reside in any
5
combination of features of claim 1
In accordance with an embodiment of the present invention, the twin rod
gear shift assembly for manual transmission comprises a housing having a distal
5 end and a proximal end, at least one shift lever mounted on the distal end of the
housing, at least one detent lever mounted on the proximal end of the housing, at
least two connecting rods, a plurality of arm lever guide configured to connect at
least two connecting rods with at least one shifl lever and at least one detent lever.
Further, at least two connecting rods are connected in parallel and configured to
10 transfer a shift load from at least one shift lever to at least one detent lever.
In accordance with an embodiment of the present invention, the housing
is configured to attach with a vehicle chassis at a distance from a transmission of
the vehicle.
15
In accordance with an embodiment of the present invention, at least one
shift lever is configured to rotate in lateral and longitudinal directions. In other
words, at least one shift lever is rotatable in all gear positions.
20 In accordance with an embodiment of the present invention, at least one
detent lever is configured to act as an actuating lever of the said transmission.
Preferably, the detent lever is mounted above the transmission.
In accordance with an embodiment of the present invention, at least two
6
connecting rods are configured to transfer the lateral and the longitudinal
movement from at least one shift lever precisely to at least one detent lever.
In accordance with an embodiment of the present invention, at least two
5 connecting rods are configured to work independently of each other. In other
words, in case one of the two connecting rods malfunctions then the other
connecting rod keeps working in a normal fashion.
In accordance with an embodiment of the present invention, at least two
10 connecting rods facilitates working of at least one shift lever and at least one
detent lever in tandem.
In accordance with an embodiment of the present invention, at least two
connecting rods are removably connected with at least one shift lever and at least
15 one detent lever. Further, replacement of malfunctioned rod is easy and it does
not require dismantling of the whole gear shift assembly.
In accordance with an embodiment of the present invention, the plurality
of arm lever guide further comprises removable parts. Preferably, the removable
20 parts are, but not limited to, bolts, nuts, washers and bush.
While the present invention is described herein by way of example using
embodiments and illustrative drawings, those skilled in the art will recognize that
the invention is not limited to the embodiments of drawing or drawings described,
and are not intended to represent the scale of the various components. Further,
some components that may form a part of the invention may not be illustrated in
certain figures, for ease of illustration, and such omissions do not limit the
embodiments outlined in any way. It should be understood that the drawings and
5 detailed description thereto are not intended to limit the invention to the particular
form disclosed, but on the contrary, the invention is to cover all modificationls,
equivalent/s and alternativels falling within the scope of the present invention as
defined by the appended claim. The headings used herein are for organizational
purposes only and are not meant to be used to limit the scope of the description or
10 the claim. As used throughout this description, the word "may" is used in a
permissive sense (i.e. meaning having the potential to), rather than the mandatory
sense (i.e. meaning must). Further, the words "a" or "an" means "at least one"
unless othetwise mentioned. Furthermore, the terminology and phraseology used
herein are solely used for descriptive purposes and should not be construed as
15 limiting in scope. Language such as "including", "comprising", "having",
"containing", or "involving" and variations thereof, is intended to be broad and
encompass the subject matter listed thereafter, equivalents, and additional subject
matter not recited, and is not intended to exclude other additives, components,
integers or steps. Likewise, the term "comprising" is considered synonymous with
20 the terms "including" or "containing" for applicable legal purposes. Any discussion
of documents, acts, materials, devices, articles and the likes are included in the
specification solely for the purpose of providing a context for the present invention
8
It is not suggested or represented that any or all of these matters form a part of the
prior art base or were common general knowledge in the field relevant to the
present invention.
5 In this disclosure, whenever an element or a group of elements is
preceded with the transitional phrase "comprising", it is understood that we also
contemplate the same composition, element or group of elements with transitional
phrases "consisting of', "consisting", "selected from the group of consisting of',
"including", or "is" preceding the recitation of the composition, element or group of
10 elements and vice versa.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above recited features of the present
invention can be understood in detail, a more particular description of the
15 invention, briefly summarized above, may be had by reference to the
embodiments, some of which are illustrated in the appended drawings. It is to be
noted, however, that the appended drawings illustrate only typical embodiments of
this invention and are therefore not to be considered limiting of its scope, for the
invention may admit to other equally effective embodiments.
20
These and other features, benefits and advantages of the present
invention will become apparent by reference to the following text figure, with like
9
reference numbers referring to like structures across the views, wherein:
Fig. 1 illustrates a gear shift assembly employing a typical semi-remote
shifier (prior art).
5 Fig. 2 illustrates an isometric view of a twin rod gear shift assembly for
manual transmission in accordance with one of the preferred embodiments of the
present invention.
Fig. 3 illustrates an exploded view of the twin rod gear shifi assembly for
manual transmission as shown in fig. 2.
10 Fig. 4a illustrates a top view of a housing as shown in fig. 2.
Fig. 4b illustrates a bottom view of the housing as shown in fig. 2.
Fig. 4c illustrates an isometric view of the housing as shown in fig. 2.
Fig. 5 illustrates a front view of a shift lever as shown in fig. 2.
Fig. 6 illustrates a front view of a detent lever as shown in fig. 2.
15 Fig. 7a illustrates a front view of a connecting rod as shown in fig. 2.
Fig. 7b illustrates a top view of the connecting rod as shown in fig. 2.
Fig. 7c illustrates an isometric view of the connecting rod as shown in fig.
L.
Fig. 8a illustrates a top view of an arm lever guide as shown in fig. 2.
20 Fig. 8b illustrates a front view of the arm lever guide as shown in fig. 2
Fig. 8c illustrates an isometric view of the arm lever guide as shown in fig.
Fig. 9 is a sectional diagram illustrating controlling looseness of the twin
rod gear shift assembly for manual transmission as shown in fig. 2.
25 Fig. 10 illustrates H-Pattern of the gear shift assembly employing the
10
typical semi-remote shifter as shown in fig. 1 (prior art).
Fig. 11 illustrates H-Pattern of the twin rod gear shift assembly for manual
transmission as shown in fig. 2.
5 DETAILED DESCRIPTION OF THE DRAWINGS
The present invention is described hereinafter by various embodiments
with reference to the accompanying drawing, wherein reference numerals used in
the accompanying drawing correspond to the like elements throughout the
description. This invention may, however, be embodied in many different forms
10 and should not be construed as limited to the embodiment set forth herein. Rather,
the embodiment is provided so that this disclosure will be thorough and complete
and will fully convey the scope of the invention to those skilled in the art. In the
following detailed description, numeric values and ranges are provided for various
aspects of the implementations described. These values and ranges are to be
15 treated as examples only, and are not intended to limit the scope of the claims. In
addition, a number of materials are identified as suitable for various facets of the
implementations. These materials are to be treated as exemplary, and are not
intended to limit the scope of the invention.
20 Figure 2 illustrates an isometric view of the twin rod gear shift assembly
(200) for manual transmission in accordance with one of the preferred
embodiments of the present invention.
The assembly (200) comprises a housing (202), at least one shift lever
(204), at least one detent lever (206), at least two connecting rods (208, 208') and
a plurality of arm lever guide (210).
5 The housing (202) is adapted to mount on to the vehicle chassis at a
distance from the transmission of the vehicle as in the case of semi-remote or
remote shifters. Further, the housing (202) has a distal end (D) and a proximal end
(P). At least one shift lever (204) is configured to mount on the distal end (D) of the
housing (202) and the at least one detent lever (206) is mounted on the proximal
10 end (P) of the housing (202). At least two connecting rods (208, 208') are
connected, by virtue of plurality of arm lever guide (210) with at least one shift
lever (204) and at least one detent lever (206). Further, at least two connecting
rods (208, 208') are connected in parallel to each other.
15 As shown in figure 2, the twin rod gear shift assembly (200) for manual
transmission enables translation of shift load imposed by the driver on at least one
shift lever (204) during gear shifting operation. In the assembly (200), as soon as
the driver applies a force on at least one shift lever (204) to change the gear
position then the force applied by the driver is transferred to at least one detent
20 lever (206) via the plurality of arm lever guide (210) and at least two connecting
rods (208, 208'). The arrangement of the plurality of arm lever guide (210) and at
least two connecting rods (208, 208') translate the force precisely to at least one
detent lever (206) which in turn completes the gear shift operation. The precise
transfer of the force from at least one shift lever (204) to at least one detent lever
25 (206) happens due to the seamless coupling arrangement of at least one shift
12
lever (204) and at least one detent lever (206) by at least two connecting rods
(208, 208').
Figure 3 illustrates an exploded view of the twin rod gear shift assembly
5 (200) for manual transmission as shown in figure 2.
In accordance with an embodiment of the present invention, the housing
(202), as shown in figure 3, comprises a front mounting bracket (302) in order to
attach the housing (202) with the vehicle chassis. Further, the housing (202)
10 comprises a seat (304) at the distal end (D) of the housing (202) which holds at
least one shift lever (204) onto the housing (202). Further, the housing (202)
comprises a seat (304') at the proximal end (P) of the housing (202) which holds
the detent lever (206) with the housing (202). Also, the housing (202) comprises
other child parts, which are known in the art and the same have not been
15 described here for sake of brevity.
In accordance with an embodiment of the present invention, figure 4a
illustrates a top view of the housing (202), figure 4b illustrates a bottom view of the
housing (202) and figure 4c illustrates an isometric view of the housing (202).
20
In accordance with an embodiment of the present invention, the housing
(202) is made of, but not limited to, a polymeric material or alloy (Al or Zn alloys).
In accordance with an embodiment of the present invention, at least one
25 shift lever (204), as shown in figure 3, is inserted into a cover (306) and fastened
13
by a bolt (308) with the cover (306). Preferably, the cover (306) is made of, but not
limited to, a polymeric material and the bolt (308) is, but not limited to, a Bolt M6.
Thereafter, the fastened at least one shift lever (204) is placed onto the seat (304)
provided on the housing (202).
5
In accordance with an embodiment of the present invention, the shift lever
(204), as shown in figure 5, comprises a shift knob (2042), a shift shaft (2044)
and a pivot ball sub assembly (2046).
10 The shift knob (2042) is placed on top of the shift shaft (2044) by means
of a snap-fit mechanism. Preferably, the shift knob (2042) is made of, but not
limited to, a metal or polymeric material. Further, the shift knob (2042) may be of
any desired shape, say for example, circular, rectangular with round edges, oval,
etc.
15
In accordance with one of the preferred embodiments of the present
invention, the pivot ball sub assembly (2046) is being retained by a socket liner
(not shown). Preferably, the pivot ball sub assembly (2046) is made up of, but not
limited to, polymeric material. The pivot ball sub assembly (2046) enables at least
20 one shift lever (204) to rotate in lateral and longitudinal directions thereby
facilitating gear shifting operation.
Further, the pivot ball sub assembly (2046) is placed at the bottom end of
at least one shift lever (204). The pivot ball sub assembly (2046) is molded onto
25 the shin lever (204).
In accordance with one of the preferred embodiments of the present
invention, at least one shift lever (204), as shown in figure 5, is made up of, but not
limited to, metals or alloys.
5
In accordance with an embodiment of the present invention, at least one
detent lever (206), as shown in figure 3, is inserted into a cover (306') and
fastened by a bolt (308') with the cover (306'). Preferably, the cover (306') is made
of, but not limited to, a polymeric material and the bolt (308') is, but not limited to,
10 a Bolt M6. Thereafter, the fastened at least one detent lever (206) is placed onto
the seat (304') provided on the housing (202). Further, at least one detent lever
(206) is axially, slid-ably and rotatably mounted on the housing (202) in order to
facilitate gear shifting operations.
15 In accordance with an embodiment of the present invention, at least one
detent lever (206), as shown in figure 6, primarily comprises a shaft (2062) and a
pivot ball sub assembly (2064). Further, at least one detent lever (206), is made
up of, but not limited to, metals or alloys.
20 In accordance with an embodiment of the present invention, at least two
connecting rods (208, 208'), as shown in figure 3, are connected with at least one
shift lever (204) at one end and connected with at least one detent lever (206) at
the other end. Further, both the connecting rods (208, 208') are connected in
parallel to each other and have identical material as well as functional properties.
25 Also, at least two connecting rods (208, 208') can work independently from each
15
In accordance with an embodiment of the present invention, at least two
connecting rods (208, 208') are made up of, but not limited to, a metal or steel
5 alloys, etc. Further, both the connecting rods (208, 208') are single pieces of rods
having a straight or curved shape and do not have any joints therein.
In accordance with an embodiment of the present invention, figure 7a
illustrates a front view of the connecting rod (208), figure 7b illustrates a top view
10 of the connecting rod (208) and figure 7c illustrates an isometric view of the
connecting rod (208).
In accordance with an embodiment of the present invention, the plurality
of arm lever guide (210), as shown in figure 3, comprises a shoulder lever (322)
15 and a coupling means (310). The shoulder lever (322) at the distal end (D) of the
housing (202) is configured to hold at least one shift lever (204) and the shoulder
lever (322) at the proximal end (P) of the housing (202) is configured to hold the
detent lever (206). Further, the coupling means (310) is configured to attach one
end of at least two connecting rods (208, 208') with at least one shift lever (204)
20 and to attach other end of at least two connecting rods (208, 208') with at least
one detent lever (206).
In accordance with an embodiment of the present invention, the coupling
means (310) is a bolt such as, but not limited to, a Bolt M10. Further, the coupling
25 means (310) comprises, but not limited to, a nut (312), a washer support (314)
16
and a bush (316). The bush (316) further comprises an outer bush (318) and an
inner bush (320). Preferably, the nut (312) is, but not limited to, a Nyloc Nut and
the bush (316) is, but not limited to, a plastic bush.
5 In accordance with an embodiment of the present invention, figure 8a
illustrates a top view of the arm lever guide (210), figure 8b illustrates a front view
of the arm lever guide (210) and figure 8c illustrates an isometric view of arm lever
guide (210).
10 Figure 9 is a sectional diagram (400) illustrating controlling looseness of
the twin rod gear shift assembly (200) for manual transmission as shown in figure
2. As shown in figure 9, the connecting rod (208) is coupled with the arm lever
guide (210) by means of the bush (316), the washer support (314) and the nut
(312). Further, the arm lever guide (210) is connected with at least one shift lever
15 (204) by means of a forged joint (402). The aforesaid arrangements control the
overall looseness of the assembly (200) and enable precise performance of at
least one shift lever (204) and at least one detent lever (206). Further, the
disclosed arrangement is easy to maintain as the same comprise of easily
removable parts.
20
H-Pattern Study
Figure 10 illustrates H-Pattern (500) of the gear shift assembly employing
the typical semi-remote shifter as shown in figure. 1 (prior art). As can be seen
from figure 10, in the conventional gear shift assembly there is no sufficient gap
25 between different gear positions and due to the overlap the driver is not able to
17
transfer the shift load precisely from the shift lever to the detent lever. Further, the
driver does not get the feel and comfort as in the case of the direct shifter.
Figure 11 illustrates H-Pattern (600) of the twin rod gear shift assembly for
5 manual transmission as shown in figure. 2. As can be seen from the figure 11, in
the disclosed twin rod gear shift assembly the gear conditions are equally spaced
and facilitates precise transfer of shift load from the shift lever to the detent lever.
Further, during gear change operation the driver get the feel and comfort as in the
case of direct shifter.
10
The above-mentioned novel twin rod gear shift assembly for manual
transmission besides providing accurate transfer of movement from the shift lever
to the detent lever provides continuous operation even when one of the
connecting rod malfunctions. Further, the disclosed twin rod gear shift assembly
15 for manual transmission comprises easily removable parts, therefore, repair and
replacement of the same is easier and the overall cost of the maintenance
reduces as compared with existing technologies.
The exemplary implementation described above is illustrated with specific
20 shapes, dimensions and other characteristics, but the scope of the invention
includes various other shapes, dimensions, and characteristics. For example, the
particular shape of the housing, shift lever, detent lever, twin rods, arm lever guide
and bolt could be of appropriate sizes for any particular combination of various
parts of the twin rod gear shift assembly for manual transmission. Also, rather than
25 disclosed materials, the housing, shift knob, connecting rod, arm lever guide, nut,
18
bush, etc. may be made of other material having similar and/or enhanced
properties. Also, the components as described above could be manufactured in
various other ways and could include various other materials, including various
other plastics and also various metals.
5
Similarly, the exemplary implementations described above include
specific examples of shift lever, detent lever, housing, connecting rod, arm lever
guide, nut, bolt, bush, etc. but also any other appropriate parts, alone or in
combination, could be employed.
10
Various modifications to these embodiments are apparent to those skilled
in the art from the description and the accompanying drawings. The principles
associated with the various embodiments described herein may be applied to
other embodiments. Therefore, the description is not intended to be limited to the
15 embodiments shown along with the accompanying drawings but is to be provided
broadest scope consistent with the principles and the novel and inventive features
disclosed or suggested herein. Accordingly, the invention is anticipated to hold on
to all other such alternatives, modifications and variations that fall within the spirit
and scope of the present invention and appended claims.
20
We claim:
1. A twin rod gear shift assembly (200) for manual transmission
comprises:
5 a housing (202) having a distal end (D) and a proximal end (P)
at least one shift lever (204) mounted at said distal end (D) of said
housing (202)
at least one detent lever (206) mounted at said proximal end (P)
of said housing (202)
10 at least two connecting rods (208,208')
a plurality of arm lever guide (210) configured to connect said at
least two connecting rods (208,208') with said at least one shift lever (204) and
said at least one detent lever (206)
wherein said at least two connecting rods (208,208') are
15 connected in parallel and configured to transfer a shift load from said at least one
shift lever (204) to said at least one detent lever (206).
2. The twin rod gear shift assembly (200) for manual transmission
as claimed in claim 1, wherein said housing (202) is configured to attach with a
20 vehicle chassis at a distance from a transmission of said vehicle.
3. The twin rod gear shift assembly (200) for manual transmission
as claimed in claim 1, wherein said at least one shift lever (204) is configured to
rotate in lateral and longitudinal directions.
25
4. The twin rod gear shift assembly (200) for manual transmission
as claimed in claim 1, wherein said at least one detent lever (206) is configured to
act as an actuating lever of said transmission.
5 5. The twin rod gear shift assembly (200) for manual transmission
as claimed in claim I , wherein said at least two connecting rods (208,208') are
configured to transfer lateral and longitudinal movement of said at least one shift
lever (204) precisely to said at least one detent lever (206).
10 6. The twin rod gear shift assembly (200) for manual transmission
as claimed in claim 5, wherein said at least two connecting rods (208,208') are
configured to work independently from each other.
7. The twin rod gear shift assembly (200) for manual transmission
15 as claimed in claim 5, wherein said at least two connecting rods (208,208') are
removably connected with said at least one shift lever (204) and said at least one
detent lever (206).
8. The twin rod gear shift assembly (200) for manual transmission
20 as claimed in claim 5, wherein said at least two connecting rods (208, 208')
facilitate working of said at least one shift lever (204) and said at least one detent
lever (206) in tandem.
9. The twin rod gear shift assembly (200) for manual transmission
25 as claimed in claim 1, wherein said plurality of arm lever guide (210) further
21
comprises removable parts.
10. The twin rod gear shift assembly (200) for manual transmission
as claimed in claim 9, wherein said removable parts are bolts (308, 310), nut (312),
5 washer (314) and bush (316, 318,320).