FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
Latching Mechanism For Fully Automatic Fifth Wheel Coupling Assembly
APPLICANTS


TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTORS
Surajit Roy, Vivek Dwivedi and Rakesh Nikam
All Indian Nationals
of TATA MOTORS LIMITED,
an Indian company having its registered office
at Bombay House, 24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India

PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed.



FIELD OF INVENTION
The present invention relates to a latch releasing mechanism for a fifth wheel coupling assembly, which hitches the trailer to a vehicle.
BACKGROUND OF INVENTION
A fifth wheel coupling assembly is a device, which hitches the trailer with the tractor or prime mover. The coupling arrangement consists of a latching mechanism, the principle of which is standardized world over and commercially being used by different manufacturers. The typical coupling arrangements require manual intervention for the unlatching / unhitching of the trailer unit. There also exist specific classes of couplings where the release of the latching mechanism is hydraulically or pneumatically operated and does not require any manual intervention and commonly termed as automatic fifth wheel coupling.
The invention of air-released fifth wheel coupling assembly is disclosed in United
+ ■■■
States Patent number 6520527 wherein an automatic operation of latching and unlatching was explained. The present document claims to propose a specific latching mechanism, which can be used for the automatic fifth wheel couplings and also a retrofit kit to convert the manual fifth wheel couplings to automatic fifth wheel couplings.
Generally the commercially available fifth wheel couplings require the manual intervention of releasing the latching mechanism for uncoupling / unhitching the trailer unit. The effort required for manual intervention of heavy-duty couplings is usually quite high because of the high stiffness of the retaining springs used in the mechanism. The air released fifth wheel coupling assembly assists the truck / fleet owners in uncoupling the trailer unit wherein the release of the latching mechanism is operated through air actuated piston cylinder. The actuation of the piston is controlled by the switches provided in the driver's cabin. The fifth wheel
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coupling assemblies also consist of a safety latch which is mandatory by regulation so as to prevent the accidental release / opening of the latching mechanism. Various solutions for uncoupling the trailer unit without any manual intervention yet having all the safety features had been proposed but the problem of cost effective solutions still exist which inhibits the popularity and wide usage of automatic fifth wheel couplings. The proposed latching mechanism in this document offers one of such cost effective solutions for increasing the usage and acceptability of the automatic fifth wheel coupling assemblies in conjunction with the trailers having automatic landing legs.
SUMMARY OF INVENTION
The present invention discloses a latch releasing mechanism for a fifth wheel coupling assembly used in coupling trailer and a vehicle unit.
A latching mechanism for the automatic fifth wheel couplings of the present invention can be used as a retro-fit kit on the manual fifth wheel couplings yet having all the safety features as required by the regulation.
The mechanism according to the present invention will ensure functionality even when the automatic drives are deactivated which will be helpful in case of power-off condition
A secondary handle in the latching mechanism is provided to lift the safety latch from it's locked state to un-locked state without any manual intervention and thereby releasing the trailer unit.
A coupling flange in the latching mechanism of the present invention holds the actuator rod and also providing sliding motion to it.
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Mounting provisions of various parts of the latching mechanism are provided keeping in view the serviceability, maintainability and operability of the mechanism.
Accordingly, the present invention provides a latch mechanism for a fifth wheel coupling assembly for coupling a trailer unit and a vehicle unit said fifth wheel coupling assembly comprising: a top plate assembly being pivotally mountable on a frame member of said vehicle unit and having a V-shaped groove for coupling with a coupling member of said trailer unit; a handle assembly extending from the side of the fifth wheel coupling assembly; a safety latch member resiliently pivoted to the top plate assembly and proximal to said handle assembly; wherein bottom surface of said top plate assembly of said latch mechanism comprises: a lock bar pivotally connected to a latching lever mechanism; a handle bar and a secondary handle member; a piston-cylinder assembly coupled to an actuator rod, said piston driven actuator rod being slidingly connected to said secondary handle member and is configured to release the.resiliently pivoted safety latch member upon receiving the drive from the piston-cylinder assembly; and a pivot bracket connected to the handle bar, said pivot bracket being configured to receive the actuator rod upon release of said safety latch member 'and configured to unlock the lock bar upon further continual drive provided by the piston-cylinder assembly.
In a preferred embodiment, said cylinder of the piston-cylinder assembly is air actuated.
In a preferred embodiment, said piston-cylinder assembly is coupled to the actuator rod by means of a coupling flange and suitable coupling adaptors. The first slot is provided on the handle bar for sliding movement of the actuator rod to release the resiliently pivoted safety latch member and a second slot is provided on said handle bar for guiding movement of said secondary handle member. Also, a notch is provided on said handle bar.
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A pre-tensioned spring is provided to revert the secondary handle member to its original position. The pre-tensioned spring is connected to a spring hangar bracket fixed to the handle bar. A retainer spring is provided at the distal end of the handle bar sard retainer spring being pivoted to a reinforcement member of said top plate assembly. A first aperture is provided on said' distal end of handle bar for mounting said retainer spring. A second aperture is provided in said handle bar for flushing out foreign particles, which may clog the second slot.
A first protrusion is provided on said secondary handle for mounting said pre-tensioned spring between the spring hangar bracket fixed to the handle bar and second protrusion provided on said secondary handle.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1 shows the fifth wheel coupling assembly and a trailer, which could be
mounted onto the vehicle by means of the fifth wheel coupling assembly.
Figure 2 and 3 shows the latch releasing mechanism of the fifth wheel coupling
assembly according to this invention.
Figure 4 shows the coupling flange used in the latch mechanism
Figure 5 shows the lockjaw of the latch mechanism
Figure 6 shows an actuator rod used in the latch releasing mechanism of the
present invention.
Figure 7 and 8 shows the main handle assembly of the latch mechanism of the
**■»■* present invention
Figure 9 shows the pivot component used in the latch mechanism of the present
invention.
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DETAILED DESCRIPTION OF INVENTION
Fig. 1 represents the fifth wheel coupling assembly where the top plate assembly 1 is pivoted over pedestal legs 2 on both sides that are mounted on the frame assembly. The top plate 1 has a V-shaped groove la for the entry and exit of the kingpin 4 of the trailer unit 5. The handle assembly 3 is depicted in fig. 1, which can be actuated manually or without any manual intervention as is the case for automatic fifth wheel couplings.
Figures 2 and 3 depict the underside surface of the top plate assembly 1 which consists of welded ribs lb for the reinforcement of the top plate. Lockjaw 6 is pivoted through a pivot pin 8 and secured through a pre-tension spring 9 for automatic release of the kingpin of the trailer. Lockjaw 6 slides over a set of parallel aligned welded cross members lc of the top plate. Pivot pin 8 is secured on a groove Id of the top plate assembly and groove le on one of the welded cross member lc.
Figure 6 illustrates the lockjaw 6. The lockjaw side surface 6a has a sliding connection over the surface of the lock bar 7. The slot 6b in the lockjaw 6 is used to mount the pre-tension spring 9 whereas the slot 6c is used for the pivot pin 8. Lock bar 7 is pivoted through a pivot pin 10 to the latching lever 11 and slides on the guide-ways If of the top plate assembly The latching lever 11 rests on a spacer 12 over the lock bar. One end of the latching lever 11 is placed inside a slot formed by the welding of a slotted plate lg on the top plate. The other end of the latching lever 11 is secured with a pin joint 14 to the main handle assembly 15. Main handle assembly is connected to a retainer spring 16, which is pivoted to a welded reinforcement lh of the top plate assembly. Air actuated cylinder 17 is secured by means of fasteners 18 to the top plate by means of two cylinder mounting brackets 19 which are welded to the top plate assembly Piston 20 from
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air actuated cylinder 17 is coupled to a coupling flange 21 (Fig 4) by means of suitable coupling adapters 22.
Figure 4 illustrates the coupling flange 21 that holds the actuator rod 23 and provides a sliding fit to the actuator rod 23 by means of suitable projections 21a in the coupling flange 21. The actuator rod is illustrated in Figure 5.
Returning to figures 2 and 3, the secondary handle 24 slides'over the handle bar 25, working on the principle of slotted lever mechanism. The secondary handle 24 gets the drive from air-actuated cylinder 17. The secondary handle 24 while moving out of the slot 1k of the top plate assembly 1 lifts the safety latch 26, which is pivoted to the top plate assembly 1 by means of a torsional spring 32. As the safety latch 26 (shown in fig.l) is raised completely over the secondary handle 24, the actuator rod 23 hits the pivot bracket 27 welded to the handle, bar 25 and gives the drive to the main handle assembly 15. The main handle assembly 15 has a sliding motion over the slot 1k of the top plate assembly 1 as well as rotational movement about the pin joint 14. The notch 25a of the handle bar is positioned so as to clear the slot 1k during it's outward motion. The main handle assembly 15 also transfer it's motion to the latching lever 11 which in turn moves the lock bar 7 to it's unlocked position. The drive from the air actuated cylinder 17 is continued till the notch 25b of the handle bar 25 reaches it's unlocked position and rests over the wall lj of the top plate assembly 1 (shown in fig. 1), where a electromagnetic switch/position sensor will be activated, giving the signal to the control unit of the cylinder actuation. The air from the cylinder 17 is released once the main handle assembly 15 reaches it's desired intended position. The secondary handle 24 goes back to it's original position by the help of pre-tension spring 31 • which is connected to the spring hanger bracket 29 welded to the handle bar 25 and projection 24b of the secondary handle 24. The release/latching mechanism of the coupling is similar to the operation of any standard fifth wheel couplings.
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Figures 7 and 8 represents the main handle assembly 15 along with handle bar 25, pivot bracket 27, secondary handle 24, pre-tension spring 31 and handle grip extension 30. The handle bar 25 in fig. 3 has two slots 25a and 25b. Slot 25a is used for the movement of the actuator rod 23 and slot 25b is used to guide the secondary handle 24. The hole 25c is used for mounting the retainer spring 16 and the hole 25d will be used as a passage for the flushing out foreign particles which may clog the slot 25b and may restrict the movement of secondary handle 24. The secondary handle 24 consists of a hole 24a for the connection with actuator rod and a small projection 24b for mounting the pre-tension spring 31 between the spring hanger bracket 29 welded to the handle bar 25 and projection 24b of the secondary handle 24. Fig. 4 represents the pivot bracket 27 (Figure 9), which is welded to the handle bar 25.
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WE CLAIM
1. A latch mechanism for a fifth wheel coupling assembly for coupling a
trailer unit and a' vehicle unit said fifth wheel coupling assembly
comprising:
a top plate assembly being pivotally mountable on a frame member of said vehicle unit and having a V-shaped groove for coupling with a coupling member of said trailer unit;
a handle assembly extending from the side of the fifth wheel coupling assembly;
a safety latch member resiliency pivoted to the top plate assembly
and locking said handle assembly; .
wherein bottom surface of said top plate assembly of said latch mechanism comprises:
a lock bar pivotally connected to a latching lever mechanism;
a handle bar and a secondary handle member;
a piston-cylinder assembly coupled to an actuator rod, said piston driven actuator rod being slidingly connected to said secondary handle member and is configured to release the iesiliently pivoted safety latch member upon receiving the drive from the piston-cylinder assembly; and
a pivot bracket connected to the handle bar, said pivot bracket being configured to receive the actuator rod upon release of said safety latch member and configured to unlock the lock bar upon further continual drive provided by the piston-cylinder assembly.
2. The latch mechanism as claimed in claim 1, wherein said cylinder of the
piston-cylinder assembly is air actuated.
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3. The latch mechanism as claimed in claim 1, wherein said piston-cylinder assembly is coupled to the actuator rod by means of a coupling flange and suitable coupling adaptors.
4. The latch mechanism as claimed in claim 1, wherein a first slot is provided on the handle bar for sliding movement of the actuator rod to release the resiliently pivoted safety latch member and a 'second slot is provided on said handle bar for guiding movement of said secondary handle member.
5. The latch mechanism as claimed in claim 1, wherein a notch is provided on said handle bar.
6. The latch mechanism as claimed in claim 1, wherein a pre-tensioned spring is provided to revert the secondary handle member to its original position.
7. The latch mechanism as claimed in claim 6, wherein said pre-tensioned spring is connected to a spring hangar bracket fixed to the handle bar.
8. The latch mechanism as claimed in claim 1, wherein a retainer spring is provided at the distal end of the handle bar said retainer spring being pivoted to a reinforcement member of said top plate assembly.
9. The latch mechanism as claimed in claim 8, wherein a first aperture is provided on said distal end of handle bar for mounting said retainer spring.
10. The latch mechanism as claimed in-claim 1 and 4, wherein a second aperture is provided in said handle bar for flushing out foreign particles, which may clog the second slot.
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11. The latch mechanism as claimed in claim 1 and 6, wherein a first protrusion is provided on said secondary handle for mounting said pre-tensioned spring between the spring hangar, bracket fixed to the handle bar and second protrusion provided on said secondary handle.
12. The latch mechanism as claimed any one of the preceding claims, wherein said latch mechanism is capable of being retrofitted onto an existing fifth wheel coupling.
13. The latch mechanism as claimed any one of the preceding claims, wherein said latch mechanism is fully automatic or fully manual.
14. The latch mechanism as hereinabove described with reference to the accompanying drawings.
15. A fifth wheel coupling assembly having the latch mechanism as claimed in
any one the preceding claims.
Dated this 8th day of October 2008
TATA MOTORS LIMITED
By their Agent and Attorney

(KARUNA GOLERIA) of DePENNING & DePENNING
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