FIELD

The present invention relates to the field of automated gauging. More specifically, it relates to automated gauging in a synchromesh gearbox.

DEFINITIONS

As used in the present disclosure, the following term is generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicate otherwise.
The expression 'centring' used hereinafter in this specification refers to, but is not limited to, the act of bringing a shifter fork in a synchromesh gearbox at equal distance from adjacent gears on the main shaft is termed as centring.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
In a synchromesh gearbox, a shifting element is formed by a shifter fork together with a sleeve sliding on a hub which is fixed on the main shaft. This shifting element can be slid in either direction to firstly mesh with a synchronizer ring, which goes ahead to press its cone surface on a complementary cone surface formed on a gear to synchronize speeds of the hub and the gear. Further, the sleeve meshes with the tooth formed on a side surface of the gear, thus completing a 'gear-shift'.
Before a synchromesh gearbox is mounted onto a vehicle, 'centring' of each of the shifting elements is done. Since each sleeve is utilized for engaging with a gear on its either lateral side, it is required that the shifter fork is placed on the sleeve equidistantly between two adjacent gears with a high degree of accuracy. Otherwise, due to the equal length of throw of a gear shifter handle for each speed ratio, after shifting is performed, more force will be applied on the cone of one of the gears leading to wear and tear, and an inadequate frictional force will be

applied on the one opposite to it. In either case, this will cause slippage of gears during shifting and power loss during power transmission.
One of the ways of ensuring centring of the shifting element in a synchromesh gearbox is performing manual gauging of the error in centring using a precision measurement device such as Vernier calliper and thereafter, centring the shifting element. This is a tedious, time-consuming process involving a number of calculations per centring operation. Therefore, manual measurement of error in centring is prone to human errors. It is found that the tolerance level achieved through this process is not within the acceptable range. Another method of ensuring proper centring of the shifting element in the synchromesh gearbox is by using a set of graded spacers. Any additional element incurs additional material and manufacturing cost, which is sought to be avoided on a mass production scale.
Therefore, a setup is required, which implements automation of the gauging of centring error and allows performing centring thereafter, of shifting elements in a synchromesh gearbox, thereby eliminating the abovementioned drawbacks.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of the present invention is to provide an apparatus for automated gauging of centring error of a shifting element in a synchromesh gearbox.
Another object of the present invention is to minimize centring error of a shifting element by eliminating human intervention in gauging.
Yet another object of the present invention is to eliminate wearing out of friction plates and power loss at power transmission in a synchromesh gearbox.

Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure envisages an apparatus for automated gauging of centring error of a shifting element in a synchromesh gearbox. The apparatus comprises a support structure, a shifting mechanism, a gauging unit, a repository, a movement control unit and a computational unit.
The shifting mechanism is mounted on the support structure. In an embodiment, the shifting mechanism is configured to facilitate a first movement of the shifting element between a first predetermined position and a second predetermined position and between a first predetermined position and a third predetermined position, wherein the second predetermined position and the third predetermined position are adjacent to the shifting element. The shifting mechanism is further configured to facilitate a second movement of the gauging unit from a datum position to one of the first position, the second position and the third position of the shifting element. In another embodiment, the shifting mechanism exerts a first force for facilitating the first movement of the shifting element and a second force for facilitating the second movement of the gauging unit. In yet one another embodiment, the first force is within a range of 372 N to 412 N and the second force is within a range of 78 N to 118 N. In still another embodiment, the shifting mechanism includes a pneumatic cylinder. In another embodiment, the first predetermined position is a neutral gear position.
The gauging unit is also mounted on the support structure. In an embodiment, the gauging unit is configured to measure displacements of the shifting element from a datum position to the predetermined first, second and third positions. The gauging unit is further configured to generate a plurality of displacement signals corresponding to the measured displacements. In an embodiment, the gauging unit includes a contact-type probe and a mechanism configured to facilitate forward

and backward movement of the probe. In another embodiment, the contact-type probe is an LVDT.
The repository is configured to store a predetermined sequence of operations of the shifting mechanism.
The movement control unit is configured to control the movements of the shifting mechanism using the predetermined sequence of operations. In an embodiment, the movement control unit cooperates with the shifting mechanism, the gauging unit, the repository, the computational unit and the repository. The movement control unit is configured to control the first movement of the shifting element and the second movement of the gauging unit using the predetermined sequence of operations of the shifting mechanism.
The computational unit cooperates with the gauging unit and the predetermined sequence of operations of the shifting mechanism for computing the centring error. In an embodiment, the computational unit comprises an averaging unit and a subtraction unit. The averaging unit is configured to compute a first average value of displacement signals corresponding to the first predetermined position. The averaging unit is configured to compute a second average value of displacement signals corresponding to the second predetermined position, and a third average value of displacement signals corresponding to the third predetermined position. The subtraction unit is configured to compute a first difference value between the first average value and the second average value, a second difference between the third average value and the first average value, and a third difference value between the second difference value and the first difference value, wherein the third difference value is centring error of shifting element in the synchromesh gearbox.
In another embodiment, the apparatus includes a mounting pallet which is configured for mounting the synchromesh gearbox and for traversing along a worktable.

In yet another embodiment, the apparatus includes a stopper device for facilitating measurement in the neutral gear position. In still another embodiment, the stopper device is a pneumatically actuated stopper cylinder.
The present disclosure also envisages a method for automated gauging of centring 5 error of a shifting element in a synchromesh gearbox, the method comprising following steps:
• performing movement of the shifting element using a shifting
mechanism controlled by a movement control unit as per a
predetermined sequence of operations stored in a repository;
10 • measuring movement of the shifting element using a gauging unit; and
• computing the centring error using a computational unit cooperating
with the gauging unit and the predetermined sequence of operations of
the shifting mechanism.
DESCRIPTION OF RELATED DRAWING
15 Figure 1A is a front view of an automated apparatus for gauging centring error of a shifting element in a synchromesh gearbox in accordance with the present disclosure;
Figure 1B is an isometric view of the apparatus shown in Figure 1A;
Figure 2 is a block diagram showing the various components of the apparatus in 20 accordance with an embodiment of the present disclosure;
Figure 3 is an isometric view depicting various elements of a shifting mechanism and a gauging unit in accordance with an embodiment of the present disclosure;
Figure 4 is a schematic diagram showing the various predetermined positions of a shifting element as well as the datum position of a gauging unit in accordance 25 with an embodiment of the present disclosure;
6

Figure 5A is a side view of a shifting mechanism and a gauging unit in operative configuration with a synchromesh gearbox in accordance with an embodiment of the present disclosure;
Figure 5B is a rear view of a shifting mechanism and a gauging unit in operative
5 configuration with a synchromesh gearbox in accordance with an embodiment of
the present disclosure;
Figure 6 is an isometric view of a mounting pallet in accordance with the present disclosure in accordance with an embodiment of the present disclosure;
Figure 7 is a schematic diagram of a synchromesh gearbox in accordance with an
10 embodiment of the present disclosure; and
Figure 8 illustrates a method for automated gauging of centring error of a shifting element in a synchromesh gearbox in accordance with an embodiment of the present disclosure.
LIST OF REFERENCE NUMERALS

1000 - apparatus
10 - synchromesh gearbox
12 - shifting element
14 - shifter fork
16 - sleeve
20 - support structure
22 - knob
24 - handle
26 - locating pins
30 - shifting mechanism
7

32 - shifting cylinder
34 - probe cylinder
36 - stopper device
40 - gauging unit
5 42 - contact type probe
50 - repository
60 - movement control unit
70 - computational unit
72 - averaging unit
10 74 - subtracting unit
80 - datum position
82 - a first predetermined position
84 - a second predetermined position
86 - a third predetermined position
15 90 - mounting pallet
91 - pre-guiding supports
92 - resting face
93 - clamping fork
94 - toggle clamp
20 95 - side handle
96 - position locking pin
8

100 - worktable
102 - loading station
104 - gauging station
DETAILED DESCRIPTION
5 Embodiments, of the present disclosure, will now be described with reference to
the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the
present disclosure to the person skilled in the art. Numerous details are set forth,
relating to specific components, and methods, to provide a complete
10 understanding of embodiments of the present disclosure. It will be apparent to the
person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
15 The terminology used, in the present disclosure, is only for the purpose of
explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms “a”, “an”, and “the” may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms “comprises”,
20 “comprising”, “including” and “having” are open ended transitional phrases and
therefore specify the presence of stated features, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, elements, components, and/or groups thereof.
When an element is referred to as being “mounted on”, “engaged to”, “connected
25 to” or “coupled to” another element, it may be directly on, engaged, connected or
coupled to the other element. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed elements.
9

The terms first, second, third, etc., should not be construed to limit the scope of
the present disclosure as the aforementioned terms may be only used to
distinguish one element, component, region, layer or section from another
component, region, layer or section. Terms such as first, second, third etc., when
5 used herein do not imply a specific sequence or order unless clearly suggested by
the present disclosure.
Terms such as “inner,” “outer,” “beneath”, “below”, “lower”, “above”, “upper”, and the like, may be used in the present disclosure to describe relationships between different elements as depicted from the figures.
10 Referring to the accompanying drawing, Figure 2 is a block diagram showing
various components of the apparatus (1000) in accordance with an embodiment of the present disclosure. The apparatus (1000) includes a shifting mechanism (30), a gauging unit (40), a movement control unit (60), a repository (50), and a computational unit (70). In an embodiment, the computational unit (70) includes
15 an averaging unit (72), and a subtracting unit (74).
Figure 7 illustrates a schematic diagram of a synchromesh gearbox (10) in accordance with an embodiment of the present disclosure. The synchromesh gearbox (10) includes a main shaft (also called an output shaft), a lay shaft and a clutch shaft (also called an input shaft). The input shaft is connected with a prime
20 mover such as an IC engine and is collinear to the main shaft. Gears on the main
shaft are free and are always in mesh with the corresponding gears mounted on and rigidly connected to the lay shaft. A clutch gear on the clutch shaft connects with a corresponding gear on the lay shaft when the clutch pedal is not pressed (i.e. in the „clutched‟ state). Each of the gears on the main shaft has a
25 „synchronizer cone teeth‟ arrangement on its lateral face. „Hubs‟ are splined on
the main shaft between two gears. A „sleeve‟ (16) is mounted on each hub and is free to slide over the hub. A „synchronizer ring‟ which is free to slide on the shaft but which can rotate along with the hub is mounted between the hub and the each
10

of the main shaft gears. The synchronizer ring has a cone surface corresponding to the cone on the cone teeth arrangement on the gears.
After declutching in order to cut power input through the input shaft, through
„forks‟ connected to the gear shifter handled by the vehicle operator, one of the
5 sleeves is made to slide in towards the corresponding gear, thereby meshing the
teeth on the sleeve with those on the synchronizer ring in that direction. When
adequate force is applied, the sleeve presses the synchronizer ring against the cone
on the gear. Due to friction between the cone surfaces, the speed of the gear
becomes same as that of the shaft, thereby „synchronizing‟ the gear with the shaft.
10 Thereafter, the sleeve slides in further over the gear and the sleeve gets locked
with the gear.
Since each sleeve is utilized for engaging with a gear on its either lateral side, it is required that the fork is placed equidistantly between two adjacent gears with a high degree of accuracy. Otherwise, due to the equal length of throw of the gear
15 shifter handle for each speed ratio, after shifting is performed, more force will be
applied on the cone on one of the gears leading to wear and tear, while an inadequate frictional force will be applied on the gear on the opposite side. In either case, this will cause slippage of gears during shifting and power loss during power transmission. Therefore, before a synchromesh gearbox is assembled onto a
20 vehicle, „centring‟ of each of the forks is required to be done.
The apparatus (1000) according to the present disclosure is configured to automate the process of gauging of error in centring of a shifter fork (14) in a synchromesh gearbox (10).
Figure 1A is a front view of an automated apparatus for gauging centring error of
25 a shifting element (12) in a synchromesh gearbox in accordance with the present
disclosure and Figure 1B is an isometric view of the apparatus shown in Figure 1A. The apparatus (1000) comprises a worktable (100), which is one of the subassembly areas in a vehicle assembly line. The worktable (100) includes a loading station (102) and a gauging station (104). In an embodiment, the loading
11

station (102) is provided on one said of the worktable (100) for loading the bulky gearboxes and a gauging station (104) is on the other side on which gauging of the centring error is performed.
Figure 6 is an isometric view of a mounting pallet (90) in accordance with the
5 present disclosure in accordance with an embodiment of the present disclosure.
The slidable mounting pallet (90) is configured to move along the worktable (100). In an embodiment, the worktable (100) is provided with sliding rails along which the mounting pallet (90) is free to slide. The mounting pallet (90) is essentially a fixture which is equipped with a set of pre-guiding supports (91) to
10 guide the placement of the gearbox (10) on the mounting pallet (90), a resting face
(92) for resting the gearbox (10), a clamping fork (93) for clamping the gearbox (10) from moving in longitudinal as well as lateral direction and a toggle clamp (94) for locking/ unlocking the clamping fork. A side handle (95) is provided on the mounting pallet (90) for facilitating forward/backward sliding of the mounting
15 pallet (90). Further, a position locking pin (96) is provided for locking position of
the mounting pallet (90) along the longitudinal direction.
Figure 3 is an isometric view depicting various elements of a shifting mechanism and a gauging unit in accordance with an embodiment of the present disclosure. The apparatus (1000) for automated gauging includes the shifting mechanism (30)
20 and the gauging unit (40) mounted on a support structure (20). The shifting
mechanism (30) is equipped with a shifting cylinder (32). In an embodiment, the shifting cylinder is a pneumatic cylinder. The gauging unit (40) is equipped with a contact-type probe (42). In an embodiment, the contact-type probe (42) is an LVDT. A predetermined sequence of operations of the shifting mechanism (30)
25 and the gauging unit (40) is stored in the repository (50). The movement control
unit (60) is provided to control the movement of the shifting mechanism (30), using the predetermined sequence of operations stored in the repository (50).
The support structure (20) shown in Figure 3 is guided along a vertical direction with a suitable guiding mechanism configured on the worktable (100) which is
12

shown be seen in Figures 1A and 1B. The support structure (20) further comprises a pair of knobs (22), a handle (24) and a pair of locating pins (26).
Figure 4 is a schematic diagram showing the various predetermined positions of a
shifting element (12) as well as the datum position of a gauging unit in accordance
5 with an embodiment of the present disclosure. The sequence of operation starts
with loading a synchromesh gearbox (10) on the mounting pallet (90) on the worktable (100). It is to be ensured that the gearbox (10) is in neutral condition, i.e., shifting element (12) should be at a first predetermined position (82) depicted in Figure 4. The mounting pallet (90) is slid towards the gauging station (104)
10 manually. Once the pallet is brought to a predetermined position, the pallet
locating pin is released in a locating block to lock position of the mounting pallet (90). Thereafter, the support structure (20) is pulled downwards from a safe upward location. The support structure (20) is located on the gearbox (10) using the locating pins (26) and then fixed using rotating knobs (22). Hereafter, a switch
15 configured to start the cycle for automated error gauging is operated.
Through the automated error gauging cycle, centring is performed for forks for
each of the gear pairs. A typical gearbox (10) has a first gear, a second gear, a
third gear, a fourth gear, a fifth gear and a reverse gear. Usually first, third and
fifth gears (adjacent to predetermined positions (84a), (84b) and (84c) respectively
20 in Figure 4) are located on one side of the neutral position of the shifting fork (the
neutral position denoted by a first predetermined position (82)), and second,
fourth and reverse gears (adjacent to predetermined positions (86a), (86b) and
(86c) respectively in Figure 4) are located on their opposite side. The gearbox (10)
includes forks. A first fork from the forks is configured to shift through first-
25 neutral-second gear positions; a second fork from the forks is configured to shift
through third-neutral-fourth gear positions; and a third fork is configured to shift
through fifth-neutral-reverse gear positions. The movement control unit (60) is
configured to control the shifting mechanism (30) as per the predetermined
sequence of operations stored in the repository (50). Particularly the movement
30 control unit (60) is configured to control forward and backward movement of the
13

shifting cylinder (32). For each movement of the shifting mechanism (30), a movement of the gauging unit (40) is performed by the movement control unit (60) for measuring the corresponding displacement.
An exemplary subset of movements in accordance with the predetermined
5 sequence shall be explained below. In an instance, the movement control unit (60)
shifts the shifting element (12), which comprises a shifter fork (14) and a sleeve
(16) as shown in Figure 7, from a first predetermined position (82) to a second
predetermined position (84) by operating the shifting cylinder (32), thus
performing a first movement. Thereafter, the movement control unit (60) performs
10 a second movement by operating a probe cylinder (34). The probe cylinder (34)
slides a sliding part of the contact-type probe (42) from a datum position (80) to the second predetermined position (84), to measure the displacement thereof of the shifting element (12), and thereby generate a corresponding displacement signal.
15 In this manner, the movement control unit (60) performs a first and a second
movement repeatedly for each position – a first, a second and a third predetermined position. The gauging unit (40) generates and communicates to the computational unit (70), multiple displacement signals for each of first, second and third predetermined positions.
20 The computational unit (70) comprises the averaging unit (72) and the subtraction
unit (74). The averaging unit (72) computes an average value of measured displacement for each predetermined position of the shifting element (12) – a first average value, a second average value and a third average value corresponding to the first, second and the third predetermined positions respectively, of the shifting
25 element (12). Hence, the subtraction unit (74) computes a first difference value
(difference between the first average value and the second average value) and a second difference value (difference between the third average value and the first average value). Finally, the subtraction unit (74) computes a third difference value – difference between second difference value and the first difference value. The
14

third difference value combined with its sign gives the centring error of the shifting element (12) upon which the movements have been performed by the movement control unit (60) using the shifting mechanism (30).
The apparatus (1000) also comprises a comparator unit (not shown in Figures) in
5 communication with the computational unit (70). The comparator unit compares
the computed third difference value with a predetermined tolerance value stored in the repository (50). If the absolute value of the third difference value exceeds the tolerance value, the operator is alerted, for example, by flashing on a display screen, that the centring is not achieved. Hence, the operator manually operates on
10 the corresponding shifting element (12) as guided by the value and the sign of the
third difference value displayed on the display screen. Once again, the automated cycle for gauging centring error as described above is made to run. If the error value falls within the predetermined tolerance limits, the centring is achieved. Hence, the movement control unit (60) now shifts the shifting mechanism (30) on
15 the next shifting element (12), by sliding the support structure (20) in a transverse
direction, along the neutral axis defined by the set of first predetermined positions (82). The automated cycle for gauging centring error, combined with manual correction, is performed thereon. In this manner, centring is performed on all the shifting elements (12) in a gearbox (10). Finally, the gearbox (10) is unloaded
20 from gauging station (104).
Figure 8 illustrates a method (2000) for automated gauging of centring error of a shifting element in a synchromesh gearbox in accordance with an embodiment of the present disclosure.
At block (2002), the method includes a step of performing movement of the
25 shifting element (12) using a shifting mechanism (30) controlled by a movement
control unit (60) as per a predetermined sequence of operations stored in a repository (50).
At block (2004), the method includes a step of measuring movement of the shifting element (12) using a gauging unit (40).
15

At block (2006), the method includes a step of computing the centring error using a computational unit (70) cooperating with the gauging unit (40) and the predetermined sequence of operations of the shifting mechanism (30).
The computation of centring error performed by the computational unit (70), as 5 disclosed in the present disclosure, is illustrated using a test conducted on a synchromesh gearbox to be fitted in a tractor. The measured displacement values for 1st gear position were 10.462 mm and 8.0380 mm. The second average value computed by the averaging unit (74) was 9.2500 mm. The measured displacement values for corresponding neutral position were 18.318 mm and 19.024 mm; thus
10 the first average value was 18.671 mm. Similarly, the measured displacement values for 2nd gear were 27.316 mm and 28.097 mm. Thus, the third average value computed was 27.097 mm. Therefore, from the corresponding neutral position, 1st and 2nd gear positions (indicated by a first difference value and a second difference value computed by the subtraction unit) were measured to be at 9.4210
15 mm (say, on operator‟s right side) and 9.0355 mm (on operator‟s left side). The finally computed value by the computational unit (70), of centring correction required, was -0.385 mm. Since this error value was within a predetermined tolerance band of +/-0.5mm, a message „Report 1 OK‟ was displayed on a display unit. Hence, the operator was not required to carry out any corrective
20 displacement of the 1st shifter fork.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a 25 departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
TECHNICAL ADVANCEMENTS
16

The present disclosure described herein above has several technical advantages including, but not limited to, the realization of an apparatus for automated gauging of centring error of a shifting element in a synchromesh gearbox that:
• minimizes centring error of a shifting element by eliminating human
5 intervention in gauging; and
• eliminates wearing out of friction plates and power loss at power
transmission in a synchromesh gearbox.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following
10 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
15 should not be construed as limiting the scope of the embodiments herein.
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
20 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 preferred embodiments, those skilled in the
25 art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated
17

element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission 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 disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.

WE CLAIM:

An apparatus (1000) for automated gauging of centring error of a shifting element (12) in a synchromesh gearbox (10), said apparatus (1000) comprising:
• a support structure (20);
• a shifting mechanism (30) and a gauging unit (40) mounted on said support structure (20);
• a repository (50) configured to store a predetermined sequence of operations of the shifting mechanism (30);
• a movement control unit (60) configured to control the movements of the shifting mechanism (30) using the predetermined sequence of operations; and
• a computational unit (70) cooperating with the gauging unit (40) and the predetermined sequence of operations of the shifting mechanism (30) for computing the centring error.
The apparatus (1000) as claimed in claim 1, wherein:
• the shifting mechanism (30) is configured to facilitate:
o a first movement of the shifting element (12) between a first predetermined position (82) and a second predetermined position (84) and between a first predetermined position (82) and a third predetermined position (86), wherein the second predetermined position (84) and the third predetermined position (86) are adjacent to the shifting element (12), and
o a second movement of the gauging unit (40) from a datum position (80) to one of the first predetermined position (82), the second

predetermined position (84) and the third predetermined position (86) of the shifting element (12);
• the gauging unit (40) is configured to measure displacements of the shifting element (12) from a datum position (80) to the predetermined first (82), second (84) and third (86) positions, and generate a plurality of displacement signals corresponding to the measured displacements;
• the movement control unit (60) cooperating with the shifting mechanism (30), the gauging unit (40), the repository (50) and the computational unit (70), and configured to control the first movement of the shifting element (12) and the second movement of the gauging unit (40) using the predetermined sequence of operations of the shifting mechanism (30); and
• the computational unit (70) comprises:
o an averaging unit (72) configured to compute a first average value of displacement signals corresponding to the first predetermined position (82), said averaging unit (72) is configured to compute a second average value of displacement signals corresponding to the second predetermined position (84), and a third average value of displacement signals corresponding to the third predetermined position (86);
o a subtraction unit (74) configured to compute a first difference value between the first average value and the second average value, a second difference between the third average value and the first average value, and a third difference value between the second difference value and the first difference value, wherein the third difference value is centring error of shifting element (12) in the synchromesh gearbox (10).

The apparatus (1000) as claimed in claim 1, wherein the apparatus includes a mounting pallet (90) which is configured for mounting the synchromesh gearbox (10) and for traversing along a worktable (100).
The apparatus (1000) as claimed in claim 2, wherein the shifting mechanism (30) is configured to facilitate to exert a first force to facilitate the first movement of the shifting element (12) and a second force for facilitating the second movement of the gauging unit (40).
The apparatus (1000) as claimed in claim 4, wherein the first force is within a range of 372 N to 412 N and the second force is within a range of 78Ntoll8N.
The apparatus (1000) as claimed in claim 1, wherein the shifting mechanism (30) includes a pneumatic cylinder (32) and a probe cylinder (34).
The apparatus (1000) as claimed in claim 1, wherein the gauging unit (40) includes a contact-type probe (42).
The apparatus (1000) as claimed in claim 7, wherein the contact-type probe (42) is an LVDT.
The apparatus (1000) as claimed in claim 1, wherein the first predetermined position (82) is a neutral gear position.
). The apparatus (1000) as claimed in claim 9, wherein the apparatus includes a stopper device (36) for facilitating measurement in the neutral gear position.
. The apparatus (1000) as claimed in claim 10, wherein the stopper device (36) is a pneumatically actuated stopper cylinder.

A method (2000) for automated gauging of centring error of a shifting element (12) in a synchromesh gearbox (10), the method comprising following steps:
• performing movement (2002) of the shifting element (12) using a shifting mechanism (30) controlled by a movement control unit (60) as per a predetermined sequence of operations stored in a repository (50);
• measuring movement (2004) of the shifting element (12) using a gauging unit (40); and
• computing the centring error (2006) using a computational unit (70) cooperating with the gauging unit (40) and the predetermined sequence of operations of the shifting mechanism (30).