FIELD OF INVENTION
The present invention relates to a system of deformable hood switch and hood
lock member in a vehicle for reduction in head injury criteria. The application ·
introduces the system for enhanced pedestrian protection during a collision
between pedestrian and motor vehicle.
BACKGROUND/PRIOR ART
Hood switch is normally Installed in the vehicle. Referring to fig 1, the hood
switch (1) is placed between hood (2) and hood lock member (3). The switch
mounted on the hood lock member (3) is located in proximity to front bumper
(4).
The provision of the hood switch at the upper front portion of the vehicle is
made so as to absorb energy in the course of a collision between a pedestrian
and a vehicle.
Regarding an existing hood switch, reference may be made to fig 2. Said hood
switch comprises a bracket (lA) accommodating a spring loaded plunger (2A)
through a through hole in its upper (3A) and lower mounting plate (4A) to guide
the plunger. The bracket is integrated to an anti rotation feature (5A), which is
bolted to underlying hood lock member (6A).
A cable (7 A) is connected to bottom of the plunger by means of a plate with two
pointed contacts for establishing contact with the lower mounting plate of the
bracket in ·order. to forward signal to the central lock system for notifying hood
status to user. There are three slots in the hood lock member for the plunger,
anti rotation feature and bolt (B).
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During pedestrian ·collision with motor vehicle .. the bracket o( hood sw1t.ch
produces the rigidity under impact energy, thereby transferring the impact
energy to the undenieath hood lock member. Thus at the time of impact,
plunger transfers the impact energy to· the bottom mounting plate of the
bracket which acts as rigid plane thereby not allowing any deformation during
the impact of head with hood and thus behaves as a hard point. Here, the
bottom mounting plate transfers the load directly on hood lock member.· This
leads to an increase in HIC value.
The aforesaid provision is associated with several drawbacks which can be
listed hereinbelow:
Increased value of HIC compromising with pedestrian safety.
Less deformation of hood switch.
High cost owing to higher thickness of bracket .
. in view of the. above, there is a requirement to devise a system of deformable
hood switch and hood lock member in a vehicle for reduction in head mJUry
criteria, which has been proposed by this application.
OBJECTS OF THE INVENTION
An objecl of this invention is to propose a system of deformable hood switch
and hood lock member in a vehicle for reduction in head injury criteria.
Another object of this invention is to propose a system of deformable hood
switch and hood lock member in a vehicle for reduction in head injury criteria
which obviates shortcomings of prior art.
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Further object of this invention IS to propose a system of deformable hood
switch and hood lock member iq. a vehicle for reduction in head injury criteria
which is cost effective.
Yet another object of this invention is to propose a system of deformable hood
switch·and hood lock member in a vehicle for reduc~ion in head injury criteria
which is light in weight comparatively.
SUMMARY OF INVENTION
According to this invention there is provided a system of deformable hood
switch and hood lock pi.ember in a vehicle for reduction in .head injury criteria
compnsmg a hood switch mounted on hood lock member by means of a
fastener in which the hood switch includes a ];>racket with an anti rotation
feature accommodating a spring loaded plunger, wherein bottom mounting
plate of bracket is provided with a bead between the plunger and fastener.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Further objects arid advantages of this invention will be more apparent from
the ensuing description when read in conjunction with the accompanymg
drawings of exemplary embodiments of invention and wherein:
Fig. 1 shows: Placement of the hood switch with respect to the peripheral parts
of vehicle.
Fig. 2 shows: Conventional system of hood switch and hood lock member in a
vehicle.
Fig. 3 shows: A system of d~formable hood switch and hood lock member in a
vehicle for reduction in head injury criteria according to the present invention.
Fig. 4shows: Hood switch of the present invention under deformation.
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UETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE
ACCOMPANYING DRAWINGS
The invention imparts teaching m respect of a system of deformable hood
switch and hood lock member in a vehicle for reduction in head injury criteria,
thereby increasing pedestrian safety in case of a collision with a vehicle.
In accordance with present invention, a novel bracket of the hood switch has
been devised to absorb the impact energy efficiently which increases the
deformability of the hood switch. The deformed hood switch is allowed to pass
·through an opening in the hood lock ·member thereby providing mrunmum
deformation. This meets the design criteria of the instant invention.
Referring to fig 3, wherein the hood switch includes a bracket (18) of lesser
thickness as compared tO the existing one. The bracket guides a spring loaded
plunger (2B). through a through hole in its upper (3B) and lower mounting plate
(4B). The bracket is integrated to an anti rotation feature (SB), which is secured
to underlying hood lock member (6B).
/\. cable (7B) is connected to bottom of the plunger by means of a plate (P) with
two pointed contacts (P1) for establishing contact with the lower mounting plate
of the bracket in order to forward signal to the central lock for notifying hood
status to user. There are a plurality of slots in the hood lock member for the
hood switch, anti rotation feature and fastening means such as bolt (B').
The provision of thinner bracket is made to weaken the . same which would
eventually facilitate deformation of the hood switch under impact energy during ·
colli"sion.
In order to prevent bending of the hood switch under hood closing load, each of
. . .
the bending lines (B 1, B2) of said bracket is provided with atleast one dart bead
(D). so as to
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maintain b_oth top and bottom plates ( 3B and 4B) of bracket m original
position i.e. in parallel to each other.
In addition to the above, there is provision of a bead (8) integrated. to bottom
mounting plate (4B) of said bracket for initiation of deformation of the switch
under head impact. The bead is placed between the plunger and bolt as best
seen in the figure 3. This is because top plate, one side surface of the bottom
plate and other side surface of the bottom plate are occupied with plunger,
cable and bolt respectively.
·The bead constitutes a curved section which forms a weaker. zone. Under
pedestrian's head impact load, the deformation of the switch initiates from ·a
line (L) adjacent to the ·bolt. To allow passage. of the deformed hood switch
downwards, a bigger slot (S) is provided in the hood lock member (68) under
the switch as illustrated in fig 4.
Thus, the provision of the bead allows movement of the deformable part of the
hood switch downwards during the pedestrian head impact thereby allowing
efficient absorption of energy, which leads to overall reduction in HIC value.
The system ·of invention· increases the deformability of bracket hood switch
during the head impact by reducing the rigidity of bracket hood switch and
allowing the partially deformed hood switch to travel freely through r.t r.ut-out
given on Hood Lock Member.
At the time of pedestrian head -impact on the top surface of hood, plunger of
hood switch pushes the bottom plate of bracket. As a result, bracket gets bent
down and passes thro·ugh the hole of hood lock member. This bending imparts
required amount of deformability to the bracket for the absorption of impact
energy which reduces th.e HIC value.
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Thus under impact of pedestrian head as per regulation, deformation of the
switch takes place for passage of the deformable part thereof through the slot
in hood member
Advantageous Features:
Improved value of HIC thereby addressing safety of pedestrian during
collision with vehicle.
Maximum deformation of hood switch.
Cost effective.
Ease in manufacturing.
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. A system of deformable hood switch and hood lock member in a vehicle
for reduction in head injury criteria comprising a hood switch mounted
on hood lock member by means of a fastener in which the hood switch
mcludes a bracket with an anti rotation- feature accommodating a spring
loaded plunger, wherein bottom mounting plate of bracket is provided
with a bead between the plunger and fastener.
2. A system of deformable hood switch and hood lock member in a vehicle
for reduction in head. injury criteria as claimed in claim 1 wherein the
bead constitutes a . curved section, which · is provided to initiate
deformation of the hood switch under head impact during collision.
3. A system of deformable hood switch and hood lock member in a vehicle
for reduction in head injury criteria as claimed in claim. 1 or 2 wherein
the bracket is having lesser thickness forming a thinner section.
4 . .A system of deformable hood switch and hood lock member in a vehicle
for reduction in head injury criteria as claimed in any of the proce.eding
claims wherein each of the bending lines of said bracket is provided with
atleast one dart bead so as to maintain hoth top and bottom plates of
bracket parallel to each otp.~r.
5. A system of deformable hood switch and hood lock member in a vehicle
for reduction in head injury criteria as claimed in any of the proceeding
claims wherein the deformation of said switch initiates from a line
adjacent to the fastener.
6. A system of deformable hood switch and hood lock member in a vehicle
for reduction in head injury criteria as claimed in any of the proceeding
claims. wherein the hood lock member comprising a bigger slot to allow
downward movement of the deformable part of switch therethrough.
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7. A system of deformable hood switch and hood lock member in a vehicle
for reduction in head injury criteria as claimed in any of the preceding
claims· is associated with the advantageous features such as herein
described.
8. A system of deformable hood switch and hood lock member in a vehicle
for reduction in head injury criteria substantially as herein described
with reference to the accompanying drawings.