FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION An Energy absorbing mechanism for seating system
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
Mahesh Mungi and Vinayak S Gogate
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
Prasad Yaligar
of Altair Engineering India Pvt Ltd,
Mercury 2B block, 5th Floor, Prestige Tech Park,
Sarjapur Marathahalli, Outer Ring Road,
Bangalore 560087, Karnataka, 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 is related to energy absorption unit in automobile and more particularly it relates to an energy absorbing mechanism for seating system to be fitted at the seat mountings.
Background of invention:
Generally the vehicle is exposed to higher deceleration levels in vertically upward direction when a vehicle experiences explosion from below or bottom. Such decelerations are not desirable for the vehicle occupants as it would result to internal injuries. The seat belt restraints are not adequate for energy absorption since the seat belt restraints are not subjected to tensile forces. In fact the seat belt restraints are subjected to compressive forces. Therefore the energy absorption systems are provided between the vehicle structure and the occupant seat to control the said decelerations transferred to the occupant. Typically the said energy absorbing systems are primarily of hydraulic piston / cylinder arrangement. The said energy absorbing system of hydraulic piston/ cylinder arrangement require special hydraulic fluids for maintaining the desired viscosity at higher temperatures produced in an explosion.
Objects of invention:
The main object of the present invention is to provide an energy absorbing mechanism for seating system provided at the seat mounting with the vehicle structure.
Another object of the present invention is to provide an energy absorbing mechanism for seating system which is reusable.
Yet another object of the present invention is to provide an energy absorbing mechanism for seating system which simple in construction and cost effective.
Statement of invention
An energy absorbing mechanism for seating system comprises; an outer member, a penetrating mandrel, said outer member having plurality of vertical slots to constitute plurality of flakes, said outer member is provided with a tapered

hole, said flakes having plurality of steps provided on inner side, said mandrel having plurality of extensions with shoulder which operably engage with the said steps provided on said flakes during penetration of said mandrel in said outer member.
An energy absorbing mechanism for seating system, in accordance with this invention, wherein the said outer member is made up from a tubular member.
An energy absorbing mechanism for seating system, in accordance with this invention, wherein the said outer member is made up from a rigid rod.
An energy absorbing mechanism for seating system, in accordance with this invention, wherein said steps are having entry chamfers for easy sliding of the said mandrel.
An energy absorbing mechanism for seating system, in accordance with this invention, wherein the numbers of said extensions on said mandrel are equal to the number of said slots provided on said outer member.
An energy absorbing mechanism for seating system, in accordance with this invention, wherein the width of the said extensions are equal to width of said slots provided on the said outer member.
An energy absorbing mechanism for seating system, in accordance with this invention, wherein said mandrel is connected to the vehicle structure and said outer member is connected to seat structure.
An energy absorbing mechanism for seating system, in accordance with this invention, wherein said mandrel is connected to the seat structure and said outer member is connected to vehicle structure.
An energy absorbing mechanism for seating system, in accordance with this invention, wherein said flakes or bending arms are operated within elastic limit of the material.

An energy absorbing mechanism for seating system, in accordance with this invention, wherein said tapered hole is blind at bottom end of said outer member.
A method of dismantling said mandrel from said outer member comprising the steps of; applying an opposite force to the assembly to disengage the said shoulder from said step on the outer member; rotating said mandrel till the said extensions are aligned with the said vertical slots on the outer member; reducing the force on the assembly gradually to facilitate safe disengagement of said mandrel and outer member.
Brief description of drawings:
Figure - 01 shows isometric view of seating system.
Figure - 02 shows an isometric view of the energy absorbing mechanism for
seating system in accordance with the present invention.
Figure - 03 show sectional side view and top view of an energy absorbing
mechanism for seating system.
Figure - 04 show the side & isometric views of the penetrating mandrel.
Figure - 05 show sectional side view and top view of the assembly of an energy
absorbing mechanism for seating system.
Figure - 06 shows isometric view of the energy absorbing unit during dismantling.
Brief description of invention:
In accordance with the present invention, an energy absorbing mechanism for seating system comprises; an outer member 2.2, a penetrating mandrel 2.1, said outer member having plurality of vertical slots 2.2.3 to constitute plurality of flakes 2.2.4. Said outer member is provided with a tapered hole 2.2.5 of adequate length for energy absorption. Said flakes 2.2.4 having plurality of steps 2.2.2 provided on inner side, said steps having entry chamfers 2.2.6 for easy sliding of the said mandrel 2.1. Said mandrel 2.1 having plurality of extensions 2.1.1 with shoulder 2.1.2 to operably engage with the said steps 2.2.2 provided on said flakes of outer member. The numbers of said extensions on said mandrel are equal to the number of said slots provided on said outer member.

The said mandrel having a shank 2.1.3, a tapered end 2.1.4 portion comprises plurality of extensions 2.1.1 and shoulder 2.1.2. The width of the said extensions 2.1.1 is equal to the width of the said slots provided on the said outer member.
Detailed description of invention
Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same.
In accordance with the present invention, an energy absorbing mechanism for seating system comprises; an outer member 2.2, a penetrating mandrel 2.1, said outer member having plurality of vertical slots 2.2.3 to constitute plurality of flakes 2.2.4. Said outer member is provided with a tapered hole 2.2.5 of adequate length for the energy absorption. Said flakes 2.2.4 having plurality of steps 2.2.2 provided on inner side of said flakes and said steps having entry chamfers 2.2.6 for easy sliding of the said mandrel 2.1. Said mandrel 2.1 having plurality of extensions 2.1.1 with shoulder 2.1.2 to operably engage with the said steps 2.2.2 provided on said flakes of outer member. The numbers of said extensions on said mandrel are equal to the number of said slots provided on said outer member. The said mandrel having a shank 2.1.3, a tapered end 2.1.4 portion comprises plurality of extensions 2.1.1 and shoulder 2.1.2. The width of the said extensions 2.1.1 is equal to the width of the said slots provided on the said outer member.
Now referring to figure-01 which shows a seat 1 attached to the vehicle structure 3 through energy absorbing system - EA system 2. Each seat having at least two attachment points and each said attachement point comprises of said EA system 2.
Now referring to figure -02, which show energy absorbing system for seating system in accordance with this invention. The said energy absorbing mechanism comprises an outer member 2.2 and a penetrating mandrel 2.1. During attachment of the seat to the vehicle structure, the said outer member 2.2 is connected to the seat structure and the said mandrel 2.1 is connected to the vehicle structure. However based on the application, the same arrangement can

be reversed. The said outer member 2.2 is having plurality of vertical slots 2.2.3 to constitute plurality of flakes a 2.2.4. The said mandrel 2.1 comprises plurality of extensions 2.1.1 with shoulder 2.1.2 to operably engage with the said steps 2.2.2 provided on said flakes 2.2.4 of said outer member 2.2. The numbers of said extensions 2.1.1 on said mandrel 2.1 are equal to the number of said slots provided on said outer member 2.2.
Referring to figure-03 which shows cross sectional side view and top view of the said outer member. The outer member 2.2 is provided with a tapered hole 2.2.5. The length of the said tapered hole 2.2.5 is adequate for required energy absorption. The plurality of steps 2.2.2 are provided on inner side of said flakes 2.2.4 of said outer member 2.2. The said steps 2.2.2 comprise entry chamfers 2.2.6 for easy sliding of the said mandrel 2.1. The said outer member is having plurality of vertical slots 2.2.3 to constitute plurality of flakes 2.2.4 which acts as plurality of bending arms. The said outer member 2.2 is manufactured either from a tubular member or a rigid rod. Said tapered hole 2.2.5 is blind at the bottom end of said outer member 2.2 when said outer member is manufactured from a rigid rod.
Referring to figure-04 which shows side view and isometric view of the geometry of said penetrating mandrel 2.1. The said mandrel 2.1 comprises a shank portion 2.1.3, a tapered end 2.1.4 having plurality of extensions 2.1.1 and shoulder 2.1.2. The number of extensions 2.1.1 provided on said mandrel 2.1 is equal to the number of slots 2.2.3 provided on the said outer member 2.2. The width of the said extensions 2.1.1 are equal to the width of the said slots 2.2.3 on the said outer member 2.2 such that the said mandrel 2.1 slides easily in to said outer member 2.2 during operation.
Referring to figure-05 which shows the cross sectional and top view of assembly of the said outer member 2.2 with the said penetrating mandrel 2.1. The penetration of the said mandrel 2.1 pushes the said flakes or bending arms 2.2.4 outwards. The said steps 2.2.2 engage with the shoulder 2.1.2 of the said penetrating mandrel 2.1 which enables to retain the penetrated position of the said penetrating mandrel.

Referring to figure-06 which shows the assembly of the said mandrel 2.1 with the said outer member 2.2 wherein said the said mandrel 2.1 is rotated appropriately such that the said extensions 2.1.1 on the said mandrel aligns with the said slots 2.2.3 on the said outer member 2.2 thereby facilitating the easy removal of penetrated mandrel 2.1 from the said outer member 2.2.
During vertical deceleration, the vehicle structure moves upwards whereas the seat occupied by an occupant tends to retain its position in space. Thus in totality the seat moves relatively downwards compared to the vehicle structure. In this movement, force is generated between the vehicle structure and the seat structure. This force is applied on the energy absorbing mechanism of the present invention resulting in penetration of the said mandrel 2.1 inside the said outer member 2.1. The penetration of said mandrel 2.1 in said outer member 2.2 forces the said flakes or bending arms 2.2.4 to bent outwards resulting in energy absorption. Since the outer member 2.2 is having tapered hole 2.2.5, the said mandrel 2.1 experiences a continuously increasing force with its penetration depth. The said mandrel 2.1 is penetrated against the assembly force of the said energy absorbing mechanism which absorbs the energy during the penetration. The amount of energy absorbed increases with the penetration of mandrel in said outer member.
As the said mandrel 2.1 is being pushed against the outer member 2.2, the said mandrel 2.1 also experiences a reaction to move in opposite direction. However due to the engagement of the said shoulder 2.1.2 with the said steps 2.2.2, such reverse movement is prevented and energy is stored in the mechanism.
During dismantling of the said mandrel 2.1 and the said outer member 2.2, an opposite force is applied to the assembly to disengage the said shoulder with the said step on the outer member. The said mandrel 2.1 is rotated till the said extensions 2.1.1 are aligned with the said vertical slot 2.2.3 on the outer member 2.2. The force on the assembly is reduced gradually to facilitate safe disengagement. After the disengagement of the said mandrel 2.1 from the said outer member 2.2, the said energy absorbing mechanism is reusable.

In accordance with this invention, A method of dismantling said mandrel from said outer member comprising the steps of; applying an opposite force to the assembly to disengage the said shoulder from said step on the outer member; rotating said mandrel till the said extensions are aligned with the said vertical slots on the outer member; reducing the force on the assembly gradually to facilitate safe disengagement of said mandrel and outer member.
The said flakes or bending arms 2.2.4 of said outer member 2.2 are designed in such a way that the material of said outer member 2.2 remains within its elastic limit with the highest penetration of the said mandrel enabling to reuse the said energy absorbing mechanism after disengaging said mandrel from said outer member.
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included as they come within the scope of the invention as claimed or the equivalents thereof.

We claim
1. An energy absorbing mechanism for seating system comprises; an outer member, a penetrating mandrel, said outer member having plurality of vertical slots to constitute plurality of flakes, said outer member is provided with a tapered hole, said flakes having plurality of steps provided on inner side, said mandrel having plurality of extensions with shoulder which operably engage with the said steps provided on said flakes during penetration of said mandrel in said outer member.
2. An energy absorption mechanism for seating system as claimed in claim 1, wherein said outer member is made up from a tubular member.
3. An energy absorption mechanism for seating system as claimed in claim 1, wherein the said outer member is made up from a rigid rod.
4. An energy absorbing mechanism for seating system as claimed in claim 1, wherein said steps are having entry chamfers for easy sliding of the said mandrel.
5. An energy absorbing mechanism for seating system as claimed in claim 1, wherein the numbers of said extensions on said mandrel are equal to the number of said slots provided on said outer member.
6. An energy absorbing mechanism for seating system as claimed in claim 1,
wherein the width of the said extensions are equal to width of said slots
provided on the said outer member.
7. An energy absorbing mechanism for seating system as claimed in claim 1, wherein said mandrel is connected to the vehicle structure and said outer member is connected to seat structure.
8. An energy absorbing mechanism for seating system as claimed in claim 1, wherein said mandrel is connected to the seat structure and said outer member is connected to vehicle structure.
9. An energy absorbing mechanism for seating system as claimed in claim 1, wherein said flakes or bending arms are operated within elastic limit of the material.
10. A method of dismantling said mandrel from said outer member comprising the steps of; applying an opposite force to the assembly to disengage the said shoulder from said step on the outer member; rotating said mandrel till the said

extensions are aligned with the said vertical slots on the outer member; reducing the force on the assembly gradually to facilitate safe disengagement of said mandrel and outer member. 11. An energy absorbing mechanism for seating system and a method of dismantling said mandrel from said outer member, as herein described with accompanying drawings.