FORM 2
THE PATENT ACT, 1970,
(39 OF 1970)
&
THE PATENTS RULE, 2003
COMPLETE SPECIFICATION
(SEE SECTION 10; RULE 13)
"POSITIVE LOCKING SYSTEM WITH SPRING LOADED AUTO RETURN MECHANISM FOR THE TAILGATE OF UTILITY VEHICLES"
MAHINDRA & MAHINDRA LIMITED
AN INDIAN COMPANY,
R&D CENTER, AUTOMOTIVE SECTOR,
89, M.I.D.C, SATPUR,
NASHIK-422 007,
MAHARASHTRA, INDIA.
THE FOLLOWING SPECIFICATION PATICULARLY DESCRIBES THE NATURE OF THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

FIELD OF INVENTION
The present invention is related to the auto return lock for the tailgate of utility vehicle. More particularly the present invention is related to positive locking system with spring loaded auto return mechanism for the tailgate of utility vehicles
BACKGROUND OF THE PRESENT INVENTION
It is a common problem observed in Indian scenario that after certain kilometers of vehicle running, the locking mechanism of tailgate handle get loosen and remain in open / in hanging condition on many utility Vehicles. This situation alarms a safety concern to the human being. The tailgate handle in its open / hanging condition is projecting out and can act like a sharp knife edge. This may cause serious accident and injury to the human being if the tailgate opens out in running vehicle.
Therefore there is a need to provide spring loaded auto return mechanism that ensures positive locking at all the time and does not allow handle to open in the running condition of the vehicle.
OBJECTIVES OF THE PRESENT INVENTION
The main object of the present invention is to provide spring loaded auto return handle locking mechanism in commercial vehicles.
Another object of the present invention is to provide positive locking system with spring loaded auto return mechanism for the tailgate of utility vehicles.

STATEMENT OF INVENTION
Accordingly invention provides a positive locking system with spring loaded auto return mechanism for the tailgate of utility vehicles comprising an outer body consisting a pair of parallel side walls with a top length wise partially closed near about half length at one side and other side slanting open top; a slot parallel to the bottom of the said parallel walls provided to the said at one side near to the end; a hole provided to the said parallel walls near to the covered top at central part located in the said other side ; a handle member of inverted U-section, with width equal to the gap between said vertical sides of said outer body, having curved end with a slit at one end with a pair of holes at distant on vertical sides, engaged to the said hole of the said body member of the parallel walls by a rivet pin aligning with the first hole of the said pair of holes of the handle near to the said curved end; a torsion spring mounted over the said rivet with one leg engaged to the said slit of handle other leg fixed to the stationery pin on the said outer body vertical sides; a rectangular shape hook mounted engaging to the said slot in the parallel walls the said outer body and second hole of the said handle; a pair of vertical support formed on the tailgate to hinge ably support the said riveted pin; a holding hook formed on the vehicle body to engage the said rectangular hook for locking; and arrangement is such that incorporating the torsion spring and a stationary pin, with optimized slot profile of outer body and slit in the handle profile positive locking of the tailgate assembly is achieved.
DESCRIPTION OF THE FIGURES
Figure 1 shows location of the spring loaded positive locking system on the tailgate of the utility vehicle.
Figure 2A and 2B shows perspective of spring loaded positive locking system front and back view respectively according to invention;

Figure 3A shows the perspective view of the positive locking system with showing mounting of handle to outer body vvith spring loaded hook in accordance with the present invention; . Figure 3B shows torsion spring engaged to stationery pin; Figure 4A shows optimized handle slit profile;
Figure 4B shows optimized slot profile to Achieve positive locking in accordance with the present invention.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
Referring to figure 1 to 4 positive locking system (1) in accordance with the present invention comprises of outer body,1 handle lock, 2 hook outer body,3 sprinp,7 riveted ,pin,4 stationary,pin,6 slot.profile,9 slit 8 in the handle Jock for spring resting and reinforcement closure outer body. Outer body 1 and handle 2 is pivoted through the riveted pin 4 while hook 3 with circular cross-section rotates in the handle and simultaneously slides on the outer body 1. Reinforcement 5 closure outer body gets welded to outer body to provide stiffness. Torsion spring takes the support of the pin and rotates with the outer handle slit. Other end of torsion spring gets rested (locked) on the stationary pin.
Referring to figure 2 positive locking system with spring loaded auto return mechanism(1) for the tailgate of utility vehicles Comprising an outer body 1 consisting a pair of parallel side walls with a top length wise partially closed near about half length at one side. The other side outer body 1 slanting with open top. A slot 9 parallel to the bottom of the said parallel walls provided to the said at one side near to the end. A hole provided to the said parallel walls near to the covered top at central part located in the said other side ; a handle member 2 of inverted U-section, with width equal to the gap between said vertical sides of said outer body, having curved end with a slit 8 at one end with a pair of holes at distant on vertical sides, engaged to the said hole of the said body member of the parallel walls by a rivet pin 4 aligning with the first hole of the said pair of holes of the handle

near to the said curved end; a torsion spring 7 mounted over the said rivet 4 with one leg engaged to the said slit 8 of handle other leg fixed to the stationery pin 6 on the said outer body vertical sides; a rectangular shape hook 3 mounted engaging to the said slot 9 in the parallel walls the said outer body and second hole of the said handle. A pair vertical support formed on the tailgate (TG) hinge ably supports the said riveted pin. A holding hook formed on the vehicle body (VB) to engage the said rectangular hook for locking. The arrangement is such that by incorporating the torsion spring 7 and a stationary pin, 6 with optimized slot profile 9 of outer body 1 and slit 8 in the handle profile positive locking of the tailgate assembly fs achieved.
This ensure that tailgate of the utility vehicle always remain in the locked position in running condition the vehicle due to the auto return spring arrangement in the handle.
The optimized slot profile acts as an auto-stopper for the hook outer body at the defined angle for unlatching the tail-gate outer through outer handle. Torsion spring helps in positive locking and auto return of handle mechanism. For spring support, one leg is rested in the slot provided on the handle lock and other leg is locked in the pin provided on the handle lock.
In this mechanism the customer has to apply little effort for removing the hook out from the outer body slot and due to spring action the handle will come at its original locking position automatically.
The system provides safety to the user as in running condition of the vehicle there is no possibility of opening the tailgate because of auto return mechanism. It also reduces the closing effort of tailgate handle assembly and acts as a customer delight. It gives a smooth feel of auto return system during the operation.

ADVANTAGES OF THE PRESENT INVENTION
• Improved safety thorough user view point
• Less effort is required to lock the tailgate of utility vehicle.
• Very easy for operation.
• Low cost mechanism
• Deployable in all types of utility vehicles.

WE CLAIM:-
1. A positive locking system with spring loaded auto return mechanism for the tailgate of utility vehicles comprising an outer body consisting a pair of parallel side walls with a top length wise partially closed near about half length at one side and other side slanting open top; a slot parallel to the bottom of the said parallel walls provided to the said at one side near to the end; a hole provided to the said parallel walls near to the covered top at central part located in the said other side ; a handle member of inverted U-section, with width equal to the gap between said vertical sides of said outer body, having curved end with a slit at one end with a pair of holes at distant on vertical sides, engaged to the said hole of the said body member of the parallel walls by a rivet pin aligning with the first hole of the said pair of holes of the handle near to the said curved end; a torsion spring mounted over the said rivet with one leg engaged to the said slit of handle other leg fixed to the stationery pin on the said outer body vertical sides; a rectangular shape hook mounted engaging to the said slot in the parallel walls the said outer body and second hole of the said handle; a pair of vertical support formed on the tailgate to hinge ably support the said riveted pin; a holding hook formed on the vehicle body to engage the said rectangular hook for locking; and arrangement is such that incorporating the torsion spring and a stationary pin, with optimized slot profile of outer body and slit in the handle profile positive locking of the tailgate assembly is achieved.
2. A positive locking system as claimed in claim 1 wherein the said top is curved profile.
3. A positive locking system as claimed in claims 1 and 2 wherein the said longitudinal slot having profile with short vertical slot near to end of the said body.
4. A positive locking system as claimed in claims 1 to 3 wherein the said rivet holding the spring is tubular type.

5. A positive locking system as claimed in claim 4 wherein the said rivet is hinged to said tailgate support member by a pin passing through the said hollow rivet.
6. A positive locking system as claimed in claims 1 to 5 wherein reinforcement welded below the outer body top cover to have stiffness.