CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to Indian provisional patent application No.
201711002156, filed on January 19, 2017. The content of the above applications
are incorporated by reference in their entirety.
FIELD OF THE INVENTION
The present invention relates to devices that are designed to prevent the
inadvertent engagement of reverse speed gear, particularly for speed agricultural
vehicles, such as, for example, tractors. More particularly, this invention presents
an apparatus that prevents the engagement of reverse speed gear when an
agricultural vehicle is in a high range and also prevents the engagement of a
high range when the vehicle is in reverse speed gear.
BACKGROUND OF THE INVENTION
In agricultural and industrial practice it is common to operate the engine at a
generally constant speed and to vary the speed of the tractor by means of a
transmission having a large number of output speeds. If reverse high gear speed
is higher than the forward high gear speed, then the reverse high speed is
undesirable.
Further, it is undesirable for an operator to inadvertently engage reverse speed
gear at certain times. For instance, when an agricultural vehicle is travelling in a
forward direction at a significant velocity the engagement of reverse speed gear
may contribute to high wear or fatigue of the transmission and drive line
components. Also, it is felt that it may be more difficult to control a vehicle which
is travelling at high speed in reverse speed gear than it would be to control a
vehicle travelling at low speed in reverse speed gear. Moreover, in heavy haulage
3
application, agricultural vehicles such as tractors stall in reverse speed gear at
high speed range. Additionally, tractor running with no load if engaged at high
reverse speed gear speed may be undesirable to the operator of the tractor. Also
it is felt that it may be more difficult to control a vehicle which is travelling at
high speed in reverse speed gear than it would be to control a vehicle travelling
at low speed in reverse speed gear. In an example, if in the forward direction,
speed of the first gear when engaged in medium range is 3.47 km/hr, speed of
the reverse speed gear at medium reaches 11.2 km/hr leading to increase in the
speed of the reverse speed gear at high range to 37.5 km/hr. Further, if in the
forward the speed of the tractor in high speed gear in high range is 32.8 km/hr
and the reverse speed gear of the tractor in high range is 37.5 km/hr then
clearly, the speed of the reverse speed gear in the range as mentioned aforesaid
is highly detrimental.
Conventionally, the locking mechanisms for preventing high speed reverse
operation of an agricultural or industrial tractor is based on the placement of a
cog, pin or plate, occasionally spring loaded, to prevent the movement of a shift
lever into the reverse position. Other types of systems to prevent the inadvertent
engagement of reverse speed gear include the shift gate and the spring detent.
The shift gate is a simple open grid that allows movement of a shift lever in only
structured paths. The reverse position could only be reached after a shift lever
was moved through a path by the vehicle operator. The spring detent reverse
lockout device is equipped with a spring which will normally bias the shaft to the
forward gear position only. It is worth noting here that in the conventional
techniques the spring detent locks at the shift gate while and not inside the
transmission which is desirable with respect to developing solution for the
aforesaid problems.
4
In addition to the techniques discussed above, the art offers a variety of other
locking mechanisms. For example, Patent No. US 3987686A, discloses a locking
device configured for locking of high reverse speed with a hydrostatic
transmission having a forward and reverse control valve including a control valve
spool. A linkage leads from the forward-neutral-reverse control valve to the
dashboard of the vehicle. The linkage has one control link which operates the
control valve. A second linkage connects the speed range lever to a lockout
plate. When the speed range lever is positioned into the high position the lockout
plate is caused to swing into interference with the control link. This interference
between the lockout plate and the control link prevents simultaneous positioning
of the speed range lever in high position when the positioning of the forwardneutral-
reverse control valve is in the reverse position.
In another example, US4228879A to Woodburry discloses a hydro-mechanical
transmission shift control which allows single lever control of the range shift,
speed shift, and the high/low speed shift while providing automatic lockout of
reverse operation in predetermined ranges, lockout of operation at
predetermined speeds, and positive parking lockup.
Further, in US4666023A is disclosed a mechanical locking device for preventing
undesired shifting. More particularly, the aforesaid patent discloses a shifting
arrangement for a gear transmission constructed in sections to be used for
vehicles. With a common manual clutch a parking lock, a reversing transmission
and a range-change transmission are shifted. The movements of the manual
clutch in the shifting direction, respectively in the longitudinal direction of the
vehicle, actuate in a purely mechanical manner the shifting of the parking lock
and the reversing transmission. Movements of the manual clutch in selection
direction, respectively transversally to the longitudinal direction of the vehicle,
5
actuate mechanically and hydraulically the shifting of the range-change
transmission.
Furthermore, US4068540A proposes a transmission control useable with a
transmission of the type having a first change gear mechanism for establishing a
plurality of drive speeds and a second change gear mechanism for establishing
either a forward or reverse drive for each of said plurality of drive gears, the
transmission control including stop means capable of preventing the transmission
from operating in one or more selected reverse speeds to prevent high speed
reverse operation of a vehicle employing the transmission.
However, the invention disclosed herein presents a new apparatus and method
thereof for restricting the engagement of reverse speed gear when an
agricultural vehicle is in a high range and also for restricting the engagement of
the high speed range when the agricultural vehicle is in reverse speed gear. The
present invention performs the said intended functions through an inventive
arrangement of components that makes the intended function particularly
reliable, simpler and effective.
OBJECTS OF THE INVENTION
An object of the invention is to overcome the aforementioned and other
drawbacks existing in prior art systems and methods.
More particularly, it is an object of the invention is to develop a locking
mechanism to restrict engagement of reverse speed gear when high range is
engaged or alternatively to restrict engagement of high range when reverse
speed gear is engaged in an agricultural vehicle (tractor).
6
Still another object of the invention is to develop a locking mechanism to restrict
engagement of reverse speed gear in one range.
Yet another object of the invention is to develop a locking mechanism to restrict
engagement of reverse speed gear when high range is engaged or alternatively
to restrict engagement of high range when reverse speed gear is engaged in an
agricultural vehicle (tractor) in a manner as to improve the safety of the
agricultural vehicle operator.
Further object of the invention is to develop a reliable locking mechanism to
restrict engagement of reverse speed gear when high range is engaged or
alternatively to restrict engagement of high range when reverse speed gear is
engaged in an agricultural vehicle (tractor) in a manner as to improve.
Still another object of the invention is to develop a locking mechanism to restrict
engagement of reverse speed gear when high range is engaged or alternatively
to restrict engagement of high range when reverse speed gear is engaged in an
agricultural vehicle (tractor) in a manner as to simplify the construction of the
locking systems as existing in the conventional art.
These and other objects and advantages of the present invention will be
apparent to those skilled in the art after a consideration of the following detailed
description taken in conjunction with the accompanying drawings in which a
preferred form of the present invention is illustrated.
SUMMARY OF THE INVENTION:
The present application discloses a locking system configured to restrict
engagement of a reverse speed gear at a high range including restricting
7
engagement of the high range when the reverse speed gear is engaged. Further,
the system includes, in an embodiment, a cross rod speed (7) having a reduced
diameter area (7a) which further mounts a shifter lever speed (9), whereby said
shifter lever speed (9) being operably connected to a plurality of shifter bushes
(17a, 17b, 17c). Further, in another aspect, shifter bushes (17a, 17b, 17c) which
are connected to a shifter rod (12), a shifter rod (13) and a shifter rod (14)
respectively. In another embodiment, the shifter rod (12), the shifter rod (13)
and the shifter rod (14) is controlled to engage a 1st and a 2nd speed gear, a
3rd and a 4th speed gear and a reverse speed gear respectively. Further, in an
aspect, the system includes a cross rod range (6) which further mounts a shifter
lever range (8) having a protrusion (8a), whereby said shifter lever range (8)
being operably connected to shifter bushes (17d, 17e). In another embodiment,
the shifter bushes (17d, 17e) are further connected to a shifter rod low range
(15) and a shifter rod medium and high range (16) respectively. In an aspect,
the system further includes a top cover (5) having a horizontal though hole (26)
which slideably mounts a sliding pin (10) having a helical spring (28), wound on
a surface of the sliding pin (10). In an embodiment, the surface is facing the
shifter lever range (8) In another embodiment, the sliding pin (10) further has a
reduced diameter area (10a) and a non-reduced diameter area (10b) on its
surface. In an aspect, the surface is opposite to the surface facing the shifter
lever range (8). In another aspect, the horizontal through hole (26) is further
adapted to move the sliding pin (10) along X-axis (as mentioned in fig 4) in at
least one of forward and backward direction in a neutral condition. Further, top
cover has a vertical through hole (27) (not shown) which slideably mounts a
locking pin (11) and is further adapted to move the locking pin (11) along Z-axis
(as mentioned in fig 4) in at least one of forward and backward direction
between the reduced diameter area (10a) located on the sliding pin (10) and the
8
reduced diameter area (7a) located on the cross rod speed (7) in the neutral
condition.
In another aspect, the present application discloses a locking method for
restricting engagement of a reverse speed gear at a high range including
restricting engagement of the high range when the reverse speed gear is
engaged.
The method, when a high range is engaged involves rotating a cross rod range
(6) and a shifter lever range (8) in a counter-clockwise direction along a X-axis,
thereby engaging a shifter bush (17e) and a shifter rod (16). Further, in an
aspect, the rotating the cross rod range (6) and the shifter lever range (8) in the
counter-clockwise direction along X-axis leads to a protrusion (8a) located on the
shifter lever range (8) coming in contact with a sliding pin (10), a contact force
thereby generated further moving the sliding pin (10) towards a horizontal
through hole (26) housed in a top cover (5), whereby, in a preferred
embodiment, the moving the sliding pin (10) further moves a locking pin (11) in
an upward direction along Z-axis towards a vertical through hole (27) housed in
the top cover (5) from a reduced diameter area (10a) on a surface of the sliding
pin (10) to a non-reduced diameter area (10b) on the surface of the sliding pin
(10).
Further, the method, when a reverse speed gear is engaged involves switching a
cross rod speed (7) and a shifter lever speed (9) towards negative direction
along X-axis for engaging a shifter bush (17c) and a shifter rod (14). Further, the
method includes moving the locking pin (11) which is slideably mounted in a
vertical through hole (27) housed in the top cover (5) downwards along Z-axis,
9
thereby pushing the locking pin (11) outwards of a reduced diameter area (7a)
located on the cross rod speed (7).
The above and additional advantages of the present invention will become
apparent to those skilled in the art from a reading of the following detailed
description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The drawings refer to embodiments of the invention in which:
Fig.1A illustrates a condition of range being shifted from neutral to high by
actuating a Range Lever while speed is shifted from neutral to reverse by
actuating a Speed Lever.
Fig.1B illustrates a condition of speed being shifted from neutral to reverse by
actuating a speed lever while range is shifted from neutral to high by actuating a
Range Lever.
Fig.1C illustrates that in the instance of range being shifted from neutral to high,
shifting of speed from neutral to reverse is restricted.
Fig.1D illustrates that in the instance of speed being shifted from neutral to high,
shifting of range from neutral to reverse is restricted.
Fig.2 illustrates an internal shifting mechanism of an embodiment of the present
invention implemented for locking out high range for reverse and reverse for
high range in a tractor.
Fig. 3 illustrates a front-sectional view of said locking system according to an
embodiment of the present invention.
10
Fig.4 is a detailed view of the components of Fig. 2 showing speed lever, range
lever, cross rod link housing (speed and range), top cover (5), cross rod range,
cross rod speed, shifter lever range, shifter lever speed, sliding pin and locking
pin.
Fig.5 is a detailed view of the components of Fig. 2 showing cross rod links
speed and cross rod links range among other components.
Fig.6 is a detailed view of the components of Fig. 2 showing shifter bushes and
shifter forks.
Fig.7 is a detailed view of the components of Fig. 2 showing range areas and
speed areas among other components.
Fig.8 is a detailed view of the components of Fig. 2 showing sliding areas among
other components.
Fig.9 is a detailed view of the components of Fig. 2 showing protrusion provided
on shifter lever, spring, reduced diameter area provided on cross rod speed,
reduced diameter area and non-reduced diameter area provided on the sliding
pin among other components.
Fig. 10A illustrates working of said locking mechanism in neutral condition before
high gear is engaged according to an embodiment of the present invention.
Fig. 10B illustrates working of said locking mechanism when high gear is
engaged according to an embodiment of the present invention.
11
Fig. 10C illustrates working of said locking mechanism of locking out reverse
speed gear when high gear is engaged according to an embodiment of the
present invention.
Fig. 11 illustrates placement of the components in a reverse gear locked
condition according to an embodiment of the present invention.
Fig. 12A illustrates working of said locking mechanism in neutral condition before
reverse speed gear is engaged according to an embodiment of the present
invention.
Fig. 12B illustrates working of said locking mechanism when reverse speed gear
is engaged according to an embodiment of the present invention.
Fig. 12C illustrates working of said locking mechanism of locking out high range
when reverse speed gear is engaged according to an embodiment of the present
invention.
Fig. 13 illustrates placement of the components in a high range locked condition
according to an embodiment of the present invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
Although the disclosure hereof is detailed and exact to enable those skilled in the
art to practice the invention, the physical embodiments herein disclosed merely
exemplify the invention which may be embodied in other specific structure. While
12
the preferred embodiment has been described, the details may be changed
without departing from the invention, which is defined by the claims.
It will be apparent, however, to one of ordinary skill in the art that the present
invention may be practiced without specific details of the well known
components and techniques. In other instances, well known components or
methods have not been described in detail but rather in Figures in order to avoid
unnecessarily obscuring the present invention. Further specific numeric
references should not be interpreted as a literal sequential order. Thus, the
specific details set forth are merely exemplary. The specific details may be varied
from and still be contemplated to be within the scope of the present invention.
The features discussed in an embodiment may be implemented in another
embodiment.
Moreover occasional references to the conventional locking techniques are made
in order to better distinguish the present inventive disclosure discussed later in
greater detail. Few of the details pertaining to the locking mechanism are wellknown
in the art, and therefore, are described herein only in the detail required
to fully disclose the present invention.
Improving upon the conventional techniques discussed at length above
(background), in the present disclosure the inventive arrangement of the
components as shown in Fig. 2-13 clearly makes the locking system as disclosed
in the present application advantageous over the existing arts as would also
become clearer to the knowledgeable in the art with the particulars of the
aforesaid techniques being described below in greater detail.
13
Turning now to Figures, Fig. 1A shows a condition of range being shifted from
neutral to high by actuating a Range Lever 2 while speed is shifted from neutral
to reverse by actuating a Speed Lever 1. Further, Fig. 1B illustrates a condition of
speed being shifted from neutral to reverse by actuating a speed lever 1 while
range is shifted from neutral to high by actuating a Range Lever 2. Furthermore,
Fig.1C illustrates that in the instance of range being shifted from neutral to high,
shifting of speed from neutral to reverse is restricted. In addition, Fig.1D
illustrates that in the instance of speed being shifted from neutral to high,
shifting of range from neutral to reverse is restricted.
Fig.2 illustrates an internal shifting mechanism of an embodiment of the present
invention implemented for locking out high range for reverse and reverse for
high range in an agricultural vehicle which in one aspect is a tractor. The details
of the components as shown in Fig. 2 are explained and illustrated in further
details between Figures 4-9. Further, Fig. 3 illustrates a front-sectional view of
said locking system according to an exemplary embodiment of the present
invention.
As shown in Figs. 4-9, in an aspect a speed lever 1 is connected to cross rod
links speed 3a which is housed inside the cross rod link housing 3. Further, in
another aspect, areas 21, 22, 23, 24 & 25 are provided within the cross rod link
housing 3, to engage 1st, 2nd, 4th, 3rd and reverse speed gear respectively. The
cross rod links speed 3(a) is connected to the cross rod speed 7, and a shifter
lever speed (9) mounted on the cross rod speed 7.
In another embodiment, the shifter lever speed (9) is connected to shifter
bushes 17a, 17b & 17c which are connected to shifter rods 12, 13 and 14
respectively. Further, in order to engage first (rotated clock wise along x-axis)
and second gear (rotated counter clock wise), shifter lever speed 9 moves
14
towards positive direction on X-axis (axis as illustrated in Figs. 3-9) engages with
shifter bush 17a and respective shifter rod 12. Furthermore, in order to engage
third (rotated clockwise along x-axis) and fourth gear (rotated counter clockwise
along x-axis) the shifter lever speed 9 engages with shifter bush 17(b) and
respective shifter rod 13. Moreover, to engage reverse gear, the shifter lever
speed 9 is moved towards negative direction along the X-axis and rotated in
counter clock wise along x-axis to engage with shifter bush 17c and respective
shifter rod 14.
Further, in an embodiment, the cross rod speed 7 is provided with a reduced
diameter area 7a, where in a preferred embodiment, the diameter of the 7a is
less than the diameter of cross rod speed 7 and further the reduced diameter is
chosen so as to restrict the movement of cross rod 7 towards negative direction
along x-axis towards (reverse gear direction).
Further, in an embodiment, the range lever 2, connected to cross rod links range
4(a), housed inside the cross rod link housing (4). In another embodiment, the
areas 18, 19 & 20 are provided within the cross rod link housing 4, to engage
high, low and medium range respectively. In another embodiment, the cross rod
link 4(a) is connected to the cross rod range 6, and a shifter lever range 8
mounted on the cross rod range 6. Further, in another aspect, in a neutral
position, the shifter lever range (8) is provided with a protrusion 8a, the
protrusion 8a comes into contact with sliding pin 10, only when the range lever 2
is switched to high range. The shifter lever range (8) is connected to two shifter
bushes 17d, 17e and further connected to the shifter rod low range 15 and
shifter rod medium/high range 16 respectively. Further, in order to engage low
range, the shifter lever range (8) moves towards positive direction rotated in
counter clock wise direction along x-axis engaging the shifter bush 17d moving
the shifter rod low range 15 in negative direction along y-axis. Furthermore, in
15
order to engage medium range, the shifter lever range 8 is rotated clock wise
direction along x-axis engaged to the shifter bush 17e moving the shifter rod
range 16 in positive direction along y-axis. Moreover, in order to engage high
range, the shifter lever range 8 rotated counter clock wise along x-axis engages
with shifter bush 17e, moving the shifter rod range 16 in negative direction along
y-axis.
Further, in an embodiment, Top cover 5, accommodates the cross rod range 6,
cross rod speed 7, shifter lever range 8, shifter lever speed 9, the sliding pin 10
and locking pin 11 within the cover.
In a preferred embodiment, the sliding pin 10 is provided with a helical spring 28
partially compressed on the face facing towards shifter lever range 8 and
towards the other side its provided with a reduced diameter area 10a and a nonreduced
diameter area 10b both present on the surface of the sliding pin. The
sliding pin 10 is slidebaly mounted in a horizontal through hole 26 inside the top
cover 5, allowing the sliding pin to move along the X-axis back and forth to the
original position. The sliding pin 10 is provided with an external circlip on the
groove provided on the non-reduced diameter area 10b; to avoid the movement
of the sliding pin beyond the original position along x-axis in positive direction
and also to maintain its original position.
In another preferred embodiment, the locking pin 11, is slidebaly mounted in a
vertical through hole 27 inside the top cover 5 movable along Z-axis, back and
forth between the reduced diameter area 10a on the sliding ping (10) and the
reduced diameter 7a on the cross rod speed (7) in the neutral condition.
The foregoing discloses the working of the components of said ingenious locking
mechanism in a neutral condition. Turning to Figs. 10 (10A, 10B, 10C), 11, 12
(12A, 12B, 12C), and 13 which discloses the working of the locking mechanism in
16
order to achieve (1) restricting engagement of reverse speed gear when range is
shifted to high range and (2) restricting engagement of high range when reverse
gear is engaged. The details working mechanism is disclosed below.
Restricting engagement of reverse speed gear when range is shifted to
high range
In an embodiment, the range lever 2 is operated to engage high range, whereby
the crossrod link (singular) 4(a) is moved into the high range area 18 on
crossrod link (singular) housing 4. Thus, as a result the cross rod range 6 and
shifter lever range 8 is rotated counter clock wise along X-Axis to engage with
the shifter bush 17e and shifter rod 16. As the shifter lever range 8 is rotated
counter clock wise along X-Axis, in a preferred embodiment, the protrusion 8a
provided on the shifter lever range (8) comes into contact with the sliding pin
(10), whereby the force would make the sliding pin 10 move towards its negative
direction along x-axis in the horizontal through hole 26 provided in the top cover
5. Thus by this movement of sliding pin 10, the locking pin 11 is shifted upward
in Z-axis direction in the vertical through hole 27 provided on the top cover 5
from a reduced diameter area 10a to the surface diameter of the sliding pin (10).
Thus, the movement of locking pin 11 is restricted between the reduced
diameter area 7a provided on the cross rod speed 7 and the sliding pin (10).
Thus, now if the tractor operator wishes to engage reverse gear speed, he has to
engage the speed lever 1, and thus by moving the cross rod link speed 3(a) into
the area 25 provided on the cross link housing speed (3), leading to shifting of
the cross rod speed 7 and the associated shifter lever speed (9) to its negative
direction along the X-axis. However, since the locking pin 11 movement is
restricted between the sliding pin 10 and the reduced diameter area 7a provided
on the cross rod speed 7, the shifting of the cross rod speed 7 and the shifter
17
lever speed 9 to its negative direction along the X-axis is restricted, thereby
engagement of reverse gear is restricted when the shifter lever range 8 is
engaged in a high range position. Thus, a person skilled in the art would
appreciate that no free space for the movement of locking pin 11 in upward and
downward direction is provided with the implementation of aforesaid locking
mechanism.
Restricting engagement of high range when reverse speed gear is
engaged
In an embodiment, to engage reverse speed gear the tractor operator operates
the speed lever 1, and the cross rod link speed 3a is moved into the area 25
provided on the cross rod link housing 3 thus switching the cross rod speed 7
and the shifter lever speed 9 to its negative direction rotated counter clock wise
along the X-axis to engage with the shifter bush 17c and the shifter rod reverse
speed 14 moves the shifter fork 14a and the connected coupling sleeve (not
shown) in the negative direction along y- axis. Thus, in a preferred embodiment,
upon said shift of cross rod speed 7 to its negative direction along the x-axis, the
locking pin 11 slideably mounted in the vertical through hole 27 provided in the
top cover 5 is moved downwards along the z-axis pushing it outside the reduced
diameter area 7a provided on the cross rod speed 7. Thus, the movement of the
locking pin 11 is restricted along the Z-axis between the reduced diameter area
10a provided on the sliding pin 10 and the cross rod speed 7.
Now post engaging reverse speed gear, if the operator wishes to engage high
range selection, then he has to operate the range lever 2, whereby the crossrod
link (singular) 4a is moved into the high range area 18 on cross rod link housing
4. Thus, the cross rod range 6 and shifter lever range 8 and the corresponding
protrusion area 8a are to be rotated counter-clock wise along X-Axis to engage
18
with the shifter bush and shifter rod 16 moves the shifter fork high-medium (not
shown) and the connected coupling sleeve (not shown) in the negative direction
along y- axis. . However, since movement of the locking pin 11 is restricted
between the reduced diameter area 10a provided on sliding pin 10 and the cross
rod speed 7, movement of the sliding pin 10 along X-axis is restricted in the
sliding horizontal through hole 26 provided on the top cover 5. Thus, there is no
free space left for the movement of locking pin 11 in upward direction results in
sliding pin 10 being unable to slide, thereby locking the position of the sliding pin
10 as is provided with the implementation of aforesaid locking mechanism.
Thereby, counter-clock wise rotation of the range shifter lever 8 along x-axis to
engage high range is restricted because the protrusion 8A on the range shifter
lever 8 is prevented from rotation.
Fig 11, illustrates the engaged position of high range and the locked position of
locking pin 11 in the reduced diameter area (7a).
Fig 13, illustrates the engaged position of reverse speed gear and the locked
position of locking pin 11 in the reduced diameter area (10a).
The foregoing is considered as illustrative only of the principles of the invention.
Furthermore, since numerous modifications and changes will readily occur to
those skilled in the art, it is not desired to limit the invention to the exact
construction and operation shown and described. While the preferred
embodiment has been described, the details may be changed without departing
from the invention, which is defined by the claims.

WE CLAIM:
1. A Locking System configured to restrict engagement of a reverse speed
gear at a high range including restricting engagement of the high range
when the reverse speed gear is engaged, the system comprising:
a cross rod speed (7) having a reduced diameter area (7a) which further
mounts a shifter lever speed (9), whereby said shifter lever speed (9)
being operably connected to a plurality of shifter bushes (17a, 17b, 17c)
which are connected to a shifter rod (12), a shifter rod (13) and a shifter
rod (14) respectively, wherein the shifter rod (12), the shifter rod (13) and
the shifter rod (14) is controlled to engage a 1st and a 2nd speed gear, a
3rd and a 4th speed gear and a reverse speed gear respectively;
a cross rod range (6) which further mounts a shifter lever range (8)
having a protrusion (8a), whereby said shifter lever range (8) being
operably connected to shifter bushes (17d, 17e) which are further
connected to a shifter rod low range (15) and a shifter rod medium and
high range (16) respectively;
a top cover (5) having a horizontal through hole (26) which slideably
mounts a sliding pin (10) having a spring (28) wound on a surface of the
sliding pin (10), wherein the surface is facing the shifter lever range (8),
said sliding pin (10) further having a reduced diameter area (10a) and a
non-reduced diameter area (10b) on a surface of the sliding pin (10),
wherein the surface is opposite to the surface facing the shifter lever
range (8) and the horizontal through hole (26) further adapted to move
the sliding pin (10) along X-axis in at least one of positive and negative
direction in a neutral condition, said top cover (5) further having a vertical
20
through hole (27) which slideably mounts a locking pin (11) and further
adapted to move the locking pin (11) along Z-axis in at least one of positive
and negative direction between the reduced diameter area (10a) located on
the sliding pin (10) and the reduced diameter area (7A) located on the cross
rod speed (7) in the neutral condition.
2. The system of claim 1, wherein when the shifter lever range (8) is engaged
at the high range, the protrusion (8a) moves the sliding pin (10) in
the negative direction along the x-axis in the horizontal through hole (26)
located in the top cover (5), wherein said movement of the sliding pin
(10) shifts the locking pin (11) upward in the z-axis direction in the
vertical through hole (27) from the reduced diameter area (10a) to the
non-reduced diameter area (10b), thereby restricting movement of the
locking pin (11) between the sliding pin (10) and the reduced diameter
area (7a) located on the cross rod speed (7).
3. The system of claim 1, wherein when the shifter lever speed (9) engages
the reverse speed gear, the cross rod speed (7) shifts in the negative
direction along the x-axis and pushes the locking pin (11) slideably
mounted in the vertical through hole (27) outside the reduced diameter
area (7a) provided on the cross rod speed 7 while moving downwards
along the z-axis, thereby restricting movement of the locking pin (11)
along the z-axis between the reduced diameter area (10a) located on the
sliding pin (10) and the cross rod speed (7).
4. The system of claim 1, wherein to engage the 1st and the 2nd speed gear,
the shifter lever speed (9) moves in positive direction along X-axis and
further engages the shifter bush (17a) and the shifter rod (12).
21
5. The system of claim 1, wherein to engage the 3rd and the 4th speed gear,
the shifter lever speed (9) moves in the positive direction along X-axis and
further engages the shifter bush (17b) and the shifter rod (13).
6. The system of claim 1, claim 1, wherein to engage the reverse speed
gear, the shifter lever speed (9) moves in negative direction along X-axis
and further engages the shifter bush (17c) and the shifter rod (14).
7. The system of claim 1, wherein diameter of the reduced diameter area
(7a) is less than the diameter of the cross rod speed (7).
8. The system of claim 1, wherein to engage the low range, the shifter lever
range (8) moves in the positive direction along X-axis and further engages
the shifter bush (17d) which moves the shifter rod low range (15) in
positive direction along Y-axis.
9. The system of claim 1, wherein to engage the medium range, the shifter
lever range (8) moves towards right along the X-axis and further engages
the shifter bush (17e) which moves the shifter rod medium and high
range (16) in negative direction along the Y-axis.
10. The system of claim 1, wherein the top cover (5) further houses the cross
rod range (6), the cross rod speed (7), the shifter lever range (8), and the
shifter lever speed (9).
22
11. A Locking method for restricting engagement of a reverse speed gear at a
high range including restricting engagement of the high range when the
reverse speed gear is engaged, the method comprising:
when a high range is engaged:
rotating a cross rod range (6) and a shifter lever range (8) counterclockwise
along X-axis, thereby engaging a shifter bush (17e) and a
shifter rod (16), wherein the rotating the cross rod range (6) and the
shifter lever range (8) counter-clockwise along X-axis leads to a protrusion
(8a) located on the shifter lever range (8) coming in contact with a sliding
pin (10), a contact force thereby generated further moving the sliding pin
(10) towards a horizontal through hole (26) housed in a top cover (5),
whereby the moving the sliding pin (10) further moves a locking pin (11)
in an upward direction along Z-axis towards a vertical through hole (27)
housed in the top cover (5) from a reduced diameter area (10a) on a
surface of the sliding pin (10) to a non-reduced diameter area (10b) on
the surface of the sliding pin (10), thereby restricting the movement of
the locking pin (11) between the reduced diameter area (7a) provided on
the crossrod speed (7) and the sliding pin (10);
when a reverse speed gear is engaged:
switching a cross rod speed (7) and a shifter lever speed (9) in negative
direction along X-axis for engaging a shifter bush (17c) and a shifter rod
(14);