FIELD OF INVENTION
This invention relates to an anti-loosing with effective locking U-bolt and nut
assembly for motor vehicle. The assembly can he .employed m
commercial/passenger vehicle such as truck, bus, SUV.
BACKGROUND/PRIOR ART
U-bolt is implemented for attachment ·of leaf spring with axle of vehicle which is
having more load carrying capacity.
.
According to a known art, U-bolt is provided with uniform threaded parts at the
.end of each of the legs as illustrated in fig 1. The threads of said threaded part
·include threads in one direction requiring a nut for assembly of leaf spring with
the axle.
However, the above provision involves the issue of loosening of the nut under
higher impact load particularly while travelling on potholed road.
In accordance with another prior art, an anti-Ioosing bolt and nut is known to
be ·available in which said boit is integrated with left and right hand threads at
one or both ends. thereof. This also includes a respective left hand/right hand
threaded nut. The left and right hand threads can be arranged in steps with
different thickness. The threads are located below the bolt cap wherein the
external diameters of the left and right hand threads can be smaller than or
larger than the external diameter of the bolt cap.
The aforesaid prior art does not serve the purpose, for which the present
invention has been devised. Hence, the instant application proposes an antiloosing
with effective locking U-bolt and nut assembly for motor vehicle.
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OBJECTS OF THE INVENTION
An object of this invention is to propose an anti-loosing with effective locking
U-bolt and nut assembly for motor vehicle which overcomes disadvantages
associated with the prior art (s).
Another object of this invention IS to propose an anti-loosing with effective
locking· U-bolt and nut assembly for motor vehicle to avoid loosening of the nut
under impact load.
Further object of this invention is to propose an anti-loosing with effective
locking U-bolt and nut assembly for motor vehicle which is cost effective.
SUMMARY OF INVENTION
According to this invention there is provided an anti-loosing with effective
locking U-bolt and nut assembly for motor vehicle comprising a U-bolt, each
leg of which is integrated to a variable diameter threaded part at the end
thereof, which includes larger diameter part with threads in a direction
opposite to that of smaller diameter part, wherein a nut is screwed onto the
larger diameter part, peripheral surface of which establishes full contact with a
nut screwed on to the smaller diameter part.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Further objects and advantages of this invention will be more apparent frorri
the ensuing description when read in conjunction with the accompanying·
drawings of exemplary embodiments of invention and wherein:
Fig. 1 shows: Conventional U-bolt.
Fig. lA shows: U-bolt according to present invention.
Fig. 2 shows: Threaded part of U-bolt of present invention.
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Fig. 3 shows: Assembly of nut screwed on bolt of variable diameter m
accordance w~th present invention.
F'ig. 4 shows: Torquing of nuts under impact)oad.
Fig. 5 shows: Nut & bolt assembly of present invention.
DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE.
ACCOMPANYING DRAWINGS
The present invention discloses a technology in respect of an anti-loosing with
effective locking U~bolt and nut assembly applicable to automobile industry.
In this regard, reference may be made to fig 1A, wherein the U~bolt, each leg
( 1 ,2) of which is integrated to a threaded part .(T) at the end thereof. The
threaded part (T) includes first threaded part (3) ·having a plurality of left
hand/right hand threads and second threaded part (4) having multitude of
·threads in opposite direction i.e. right hand/left hand threads respectively.
Ascan be observed from fig 2, first threaded part (3) has a larger diameter than
/
the second threaded part (4).
The difference in diameter between first and second threaded part is preferably
one size. The diameter of the first and second threaded part is for example M 14
and M 12respectively as illustrated in fig 2.
There is provision of a respective nut (5, 6) for each threaded part ·(3,4). The
. respective nut is having threads accordingly i.e. left hand threaded part is
screwed with left hand threaded nut and vice versa .
.....
Th.e larger diameter nut (5) can be any nut such as hexagonal, flange nui:.
However, the smaller diameter nut (6) is preferably flange nut as shown in fig
3. So that it provides sufficient surface so as to support the peripheral surface
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of the larger diameter nut thereabove. Both the nuts of invention· are intact
with each other.
In addition to the above, the larger diameter nut (5) is devised such that, it
covers a part (B) of .second threaded part adjoining with the first threaded part
maintaining a gap from the second threaded part as shown. This requires
longer height ofthe nut (5).
The aforesaid provision leads to effective locking. In this exemplary
embodiment, the length of the second threaded part (4) is longer than that of
Lhe first threaded part (3) without restricting scope of the invention to the
same.
Now reference may be made to fig 4: In dynamic condition of vehicle under the
impact load, the larger diameter. nut (5) gets loose. with usage and as a result
moves downward by torquing down (D).
This downward movement of the nut ·compresses ·the smaller diameter . mit
(6).As the smaller diameter nut is in full surface contact with the larger
diameter nut by means of flange (F), therefore rotational movement of the larger
diameter nut leads to rotational movement of the smaller diameter nut in the
same direction. As the threads are placed in opposite direction, therefore
torquing down of the larger diameter nut cases torquing up (U) of the smaller
diameter nut in this particular case thereby further tightening the smaller·
diameter nut .under impact load.
Thus loosening of larger diameter nut results m tightenil).g of the smaller
diameter nut.
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Thus the provision of longer larger diameter nut for coverage of a portion (B) of
smaller diameter threaded part in conjunction with the provision of smaller
diameter flange nut give rise to the above phenomena, which prevents removal
of the nut unlike prior art.
The aforementioned provision does not require torquing of the nut as it was
required at every 1 OOOkm. This in turn Fesults in less maintenance cost.
Advantageous Features:
Effective locking between nut and bolt.
No need of special tool.
Avoids loosening of. the nut.
'
No requirement of torquing . during maintenance leading to less
maintenance cost.
It is to be noted that the present invention is susceptible to modifications,
adaptations and changes by those skilled in the art. Such variant embodiments
employing the concepts and features of this invention are intended to be within
. the scope of the present invention, which is further set forth under the
following claims:-

WE CLAIM:
1. An anti-loosing with effective locking U-bolt and nut assembly for motor
vehicle comprising aU-bolt, each leg of which is integrated to a variable
diameter threaded part at the end thereof, which includes larger
tliauu::ler part with threadg in a direction nppnsit.e to 'that of smaller
diameter part, wherein a nut is screwed onto the larger diameter part,
peripheral surface of which establishes full contact with·?. nut screwed
on to the smaller diameter part.
2. Ar.i anti-loosing with effective locking U-bolt and nut .assembly for motor
vehicle as claimed in claim 1 wherein the nut ori the larger diameter
threaded part is any nut including flange nut and .the nut onto the
smaller diameter threaded part is preferably flange nut to support the
nut on the larger diameter threaded part.
3. An anti-loosing with effective locking U-bolt and nut assembly for motor
vehicle.as claimed in claim 1 or·2 wherein the larger diameter nut covers
a portion of smaller diameter threaded part adjoining with the larger
diameter threaded· part maintaining a gap from the same.
4. An anti-loosing with effective locking U-bolt and nut assembly for motor
vehicle as claimed in any of the proceeding claims wherein the larger
diameter nut is longer comparatively.
5. An anti-loosing with effective locking U-bolt and nut assembly for motor·
vehicle· as claimed in any of the proceeding claims wherein under the
impact load the larger diameter nut compresses the smaller diameter nut
by torquing in a dir:ection to be loose thereby torquing the smaller
diameter nut in the same direction for further tightening.
6. An anti-loosing with effective locking U-bolt and nut assembly for motor
vehicle as claimed in any of the preceding claims is associated with the
advantageous features such as herein described.
7. An anti~loosing with eff~ctive locking U-bolt and nut assembly for motor
vehicle substantially as herein described with reference to the
accompanying drawings.