FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE LNVENTION ANTI-LOOSENING DEVICE
APPLICANT(S)
AMW MOTORS LTD
an Indian company
having its corporate office at
7th Floor, Tower 1, Equinox Business Park,
(Peninsula Techno Park), Off Bandra Kurla Road,
L. B. S. Marg, Kurla (West),
Mumbai-400 070
Maharashtra, India.

PREAMBLE TO THE DESCRIPTION
When an automobile vehicle is subjected to extreme vibrations (Hilly terrain with winding & bad roads) certain fastener joints get loosened and necessitate frequent retightening. Sometimes safety of occupants as well as other road users is seriously affected if nut loosening is not spotted in time,
FIELD OF INVENTION:
The invention relates to fastening systems using bolt and nuts that are subjected to severe vibrations and fluctuating / reversing loads.
BACKGROUND OF INVENTION:
In some applications due to severe vibration, nut loosening seriously affects the safety of occupants as well as other road users and requires frequent retightening. In those areas conventional nut locking principle are not useful (spring / serrated / tab washer, check nuts, castle nut, slotted nut with split pin and Nyloc nut) and requires some special mechanism to prevent loosening.
OBJECTIVES OF THE PRESENT INVENTION
Development of a mechanism to prevent loosening of fasteners even during adverse operating conditions.
BRIEF DESCRIPTION OF DRAWINGS:
Figure 1 - Elevation view of Anti-loosening Device. Figure 2 - Cross-section view of Anti-loosening Device.

DETAILED DESCRIPTION OF INVENTION:
The invention basically makes use of two opposite hand fasteners tightened in series preventing loosening. Below figure - 1 shows 'Anti-loosening Device'. The special bolt (1) has two different types of threads. Major portion has one hand thread (4) and end portion has opposite hand thread (5). Items (6). (7), (8), (9) and (10) are being integrated on major portion of special bolt (1). The master nut (2) is fitted on the above special bolt (1) and torque applied. The locking ring - nut (3) mounted on end portion of special bolt (1) having opposite hand thread (5), is tightened until it engages with master nut (2) surface. The figure -2 shows cross-sectional view of Anti-loosening Device.
When master nut (2) tends to get loosened for various reasons, the loosening direction results in tightening of the locking ring - nut (3), thus preventing loosening. This enables effective fastener retention.
The master nut (2) is subjected to number of forces and due to variety of factors such as vibration, joint-settling, miss-alignment, overheating, different thermal expansion, wrong application of torque, poor condition of master nuts, damaged threads and contaminated mating surface leading to master nut (2) loosening or complete separation or falling of master nut (2).
Looseness of master nut (2) reduces clamping force and when the clamping force reduces sufficiently, it allows microscopic movement of parts (6. 1, 8, 9 & 10) which results in axial loading and further loosening. If it is not spotted on time, leads to elongated holes in parent material, fatigue failure of bolt, cracks propagation in parts and bolt / nut separation. If it happens on moving part, it might result in fatal accident.

When master nut (2) try to loosen due to heavy vibrations, its axial displacement on special bolt (1) is being arrested by adjoining locking ring - nut (3) which has opposite threads. Thus this device functions as "Anti-loosening Device" and ensures effective nut retention in bolted joints.
Some of the typical applications include but not limited to:
• Spare wheel carrier mountings
• Suspension brackets mounting
• U-bolt mountings
• Engine mounting brackets and
• Cross member mountings
• Wheel nut mountings

We Claim the following:
1. Locking ring - Nut (3) profile so designed, to prevent loss of clamping force through anti-loosening qualities. Also its cost effective and simple construction ensures ease of manufacturing and service.
2. Special Bolt (1) design having a major portion as one hand thread which is adopted in suitable master nut (2) and a minor portion having opposite hand thread which is suitable to locking ring - nut (3).
3. Anti-loosening device assembly comprises of bolt (1), master nut (2) and Locking ring - Nut (3) for fastening system. Refer figure-1.