FORM 2
THE PATENT ACT, 1970,
(39 OF 1970)
&
THE PATENTS RULE, 2003
COMPLETE SPECIFICATION
(SEE SECTION 10; RULE 13)
"SWIVEL SOCKET WITH RESTRICTED SWIVEL"
MAHINDRA & MAHINDRA LIMITED A COMPANY REGISTERED UNDER THE PROVISIONS OF COMPANIES ACT, 1956 HAVING ADDRESS AT R & D CENTER, AUTOMOTIVE SECTOR, 89, M.I.D.C, SATPUR, NASHIK - 422 007, MAHARASHTRA, INDIA
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

FIELD OF INVENTION:-
The present invention is related to swivel socket during the assembly of the engine on assembly line. More particularly, the present invention is related to swivel socket with restricted degree of swivel required for the purpose.
Background of the Invention:
On the engine assembly line, the engine is mounted on the vehicle body with the help of engine mounting bracket (10) as shown in Fig. 1. The said engine mounting bracket has four bolting holes (12) to get the engine bolted to this bracket and a body mounting hole (11). The bolting of the engine block with this engine mounting bracket is done by the nut runner (13). But the said nut runner fouls with the bracket at 14 as shown in Fig. 2. Because of this fouling, the nut runner (13) cannotimpart the desired torque to the bolt and therefore the torque remains incomplete. Further, this fouling imparts the reaction/jerk to the hand of the operator during working which leads to the unsafe working condition and also may lead to the accident on the assembly line.
To address this fouling and jerking issue, conventionally crowfoot sockets (15) as shown in Fig. 1, in conjunction with the nut runner (13) is used. But the drawback of this crowfoot socket is that it requires the ample space to work at the torqueing station. Further, it imparts additional weight to the nut runner and therefore the torqueing activity becomes tedious / cumbersome to the operator at the station. The change over time required for the crowfoot socket is also more that affects on the overall productivity. The maintenance cost of the crowfoot socket is very high as it is an imported componentand service facilities are not available in the country. Further, the cost of this crowfoot socket is very high (approx. 20 lakhs plus),
Therefore, there is an unmet meet to address this problem of undesired torqueing, fouling and providing safe and efficient working environment at the torqueing station on the engine assembly line.
OBJECTIVES OF THE INVENTION:-
The main objective of the present invention is to provide a swivel socket with restricted degree of swivel during the engine assembly operation.

Another object of the present invention isto provide a swivel socket with restricted degree of swivelthat ensures the complete torque requiredto the bolt of engine mounting bracket.
Still another object of the present invention is toprovide a swivel socket with restricted degree of swivel that eliminates the fouling of engine mounting bracket.
Further object of the present invention is to provide a swivel socket with restricted degree of swivel that imparts safe and efficient working environment at the workstation on engine assembly line.
Description of the Figures:
The description of the present invention and its technical advantages will be better understood when the said description is read in conjunction with the following figures wherein,
Figure 1 discloses the engine mounting bracket with its mounting points at the engine end and the vehicle body end.
Figure 2 shows the nut runner and the engine mounting bracket with the fouling point that imparts jerk during the operation.
Figure 3 shows line diagram of swivel socket unit with the restricted swivel in accordance with the present invention.
Figure 4 shows perspective view of the swivel socket unit in accordance with the present invention.
Figure 5 describes the layout oftrigonometric relationship between swivel angle and gap for achieving the restricted swivel.
Figure 6 shows the swivel socket unit fitted to the nut runner at the torqueing station on the engine assembly line.
DESCRIPTION OF THE INVENTION:-
Toaddress above stated technical issues of undesired torqueing, fouling and unsafe and inefficient working environment, a swivel socket with restricted swivel was designed and

developed which is fitted at the front end of nut runner. The swivel socket of the invention ensures the desired torqueing of the bolts, totally eliminate the jerks and provides safe work station for the operator.
Referring to Fig. 3, the swivel socket (20) of the present invention comprises of driver (22), socket (21) and locking pins (23). The driver (22) is fitted to the shaft of the nut runner. This driver is having a spherical ball shaped portion (26) with at least a pair of grooves(24) wherein the said grooves are 180 degree with each other. The socket (21) has a across flat (25) which communicate with the bolt to be torqued. Further, it has at least a pair of holes (27) with each hole spaced from each other by 180 degrees and overlaps with the grooves of the ball shaped portion of the driver.The locking pins (23) when inserted through the holes of the socket and resting in the grooves of the ball shaped portion of the drives forms the complete assemblyof the swivel socket as shown in Fig. 4. The complete swivel socket unit with the restricted swivel fitted to the nut runner shaft at the torqueing station is shown in Fig. 6.
Working of the swivel socket Unit:
At the torqueing station on the engine assembly line, an engine is fitted with the engine mounting bracket with the help of bolts and at this point the swivel socket comes into the picture for work in the following sequence of actions.
- The swivel socket unit is fitted to the nut runner with the help of the extension bar.
- The entire unit with the swivel socket is placed on the head of the bolt for torqueing purpose.
- Then the nut runner is actuated and it runs in clock wise direction for torqueing the bolt so as to firmly attach the engine mounting bracket with the engine block.
- While torqueing, the gap defined between the ball shaped portion of the driver and socket helps for swiveling the socket unit.
- This swiveling of the socket unit permits the operator to deliver the desired torque to the bolt without any fouling and creating any jerk to the operator.
- Thus, the swivel socket unit provides safe and efficient environment at the work station.

To achieve the smooth working as stated above it was needed to give certain degree of swivel to socket itself. This swivel was to be optimized so as to avoid fouling as well as to avoid reaction jerk (extra Swivel will cause reaction jerk). By using existing universal socket fouling was avoided but it was giving immense jerk as torque is quite high 51 Nm. So it was required to restrict swivel of socket to an optimum degree.The degree of swivel also depend on the radial gap between the drive part and socket. So by adjusting the gap one can actually control the swivel. A closer look at the trigonometric relationship between swivel angle and this gap (as shown in Fig. 5) clearly shows that with certain numerical inputs one can actually find out the diameter of drive part for a particular degree of swivel as shown in Figure 3.
z: Inner radius of socket
y: Radius of drive part
x: Horizontal distance from swivel center.
a: Ball radius
b: Edge distance
D1: Zero Swivel angle
D2: Max swivel Angle
D2 - D1 :Net swivel angle
Z: Assuming flat of bolt head to be tightened. From this outer diameter of socket is found
out. Standard wall thickness is generally kept 3mm (for maximum strength-minimum
material.) From these data the value of 'z' is derived as under.
In this case A/F = 14mm, outer dia = 23mm
So z= {(23/2)-3}= 8.5mm
a: This ball fits inside the socket part & allows rotation. Keeping radial tolerance of
0.25mm for this rotation, we get value of 'a'= z-0.25
So, a= 8.5-0.25=8.25mm
b: Value of 'b' depends upon the overall length of socket. For better dynamic performance
of socket it should be at least 0.6 times the radius of ball.
So, b= 0.6*8.25= 5mm.
X: From figure 2 it is quite evident that 'x'= a+b
So, x= 8.25+5=13.25.
Required swivel is -
From OAB, tan = y/x.
From OAC, tan = z/x.

Therefore, required Swivel = -= {tan-1(z/x)} -{tan-1(y/x)}
For our purpose required Swivel is 5°,
5 '= {tan-1 (8.5/13.25)} -{tan-1(y/13.25)}
solving this equation we get y (Drive part radius) = 6.95 «7mm.
Diameter = 7mm.
The technical advantages derived by this invention are as under:
- Fouling with engine mounting bracket at the torqueing station is totally eliminated.
- Jerks during the work are totally eliminated.
- Desired torqueing to the bolt is easily achieved by the operator withing the specified time.
- It provides safe and efficient working environment at the work station.
- It is light in weight and therefore drudgery at the workstation is eliminated.
- It is a low cost and compact solution to address the issues of fouling and jerking at the work station.

We claim:
1. The swivel socket (20) with the restricted swivel comprising of driver (22), socket (21) and locking pins (23) wherein the said driver is having a spherical ball shaped portion (26) with at least a pair of grooves (24) wherein the said grooves are 180 degree with each other; the socket (21) has a across flat (25) which communicate with the bolt to be torqued wherein the said socket has at least a pair of holes (27) with each hole spaced from each other by 180 degrees and overlaps with the grooves of the ball shaped portion of the driver; a locking pins (23) when inserted through the holes of the socket and resting in the grooves of the ball shaped portion of the drives forms the complete assembly of the swivel socket.
2. The swivel socket (20) with the restricted swivel as claimed in claim 1 wherein the socket provides the restricted swivel and works in the following sequence,

- The swivel socket unit is fitted to the nut runner with the help of the extension bar;
- The entire unit with the swivel socket is placed on the head of the bolt for torqueing purpose;
- Then the nut runner is actuated and it runs in clock wise direction for torqueing the bolt so as to firmly attach the engine mounting bracket with the engine block;
- While torqueing, the gap defined between the ball shaped portion of the driver and socket helps for swiveling the socket unit;
- This swiveling of the socket unit permits the operator to deliver the desired torque to the bolt without any fouling and creating any jerk to the operator;
- Thus, the swivel socket unit provides safe and efficient environment at the work station.