Note: Descriptions are shown in the official language in which they were submitted.
~37~3~ :
The present invention relates to a vehicle carriecl device for
sensing whether the duration and the magnitude of deceleration occurring
within the vehicle will exceed predetermined values.
In safety harnesses that are used for passengers in vehicles there
is often a certain slack in one or more of the bands of *he safety harness.
Different arrangements have been suggested to eliminate said slack by ;-
tightening the bands at the moment of collision. A completely reliable
arrangement to actuate the band tightening means has, however, not yet been
suggested. ~`
Thus, the o~ject of the present invention is to achieve a device
that is able to sense in a reliable way whether an occurring collision is
powerful or just trivial, said device thus making it possible to tighten the
bands of the harness only during collisions of a certain magnitude.
According to the invention there is provided a vehicle carried device
for sensing and providing an indication when the duration and magnitude of
vehicle deceleration cxceed predetermined values comprising: a first mass
body arranged to be displaced in a first direction as the result of an ;
occurring deceleration of a certain magnitude of the vehicle; a second mass `~
body with the ability to be dïsplaced in said direction as the result of an
occurring deceleration of the vehicle; blocking member means movable into a
predetermined stable first position for preventing displacement of said ;
second mass body in said direction, said blocking member means comprising a
cup spring with a cup part having an inner periphery and locking tongues
disposed around the inner per;phery to lock the second mass body when said
blocking member means is in said predetermined stable position; actuating
member means operatively associated with said first mass body for trans-
ferring the blocking member means from said first position into a second
position as a result of the first mass body being displaced a predetermined
distance by deceleration of the vehiclel said actuating member means trans-
ferring said blocking member means by moving said cup part from a first to
~'
~ lD87~
a second position thereby freeing said locking tongues from said second ~
mass body, the second mass ~ody being displaceable in said direction by ;:
deceleration of the vehicle when said blocking member means is in said
second position, the di.splacement of said second mass body providing an -
indication that the duration and magnitude of the deceleration of the ~; :
vehicle exceed pre~etermined values; rectilinear guide means for guiding ~:
the movement of said first mass body and said second mass body; a first ;~:
spring operatively associated with said first mass body~ sai.d first mass
body being displaceable in said direction against the action of said first
spring only when ~he vehicle is given a deceleration. of a predetermined
magnitude; and a second spring operatively associated with said second mass
hody, said second mass body being displaceable in said directi.on against the `action of said second spring.
The invention is based on the knowledge that the deceleration :Eorce
is of different magnitude and duration in different types of collisions.
Thus, in minor collisions, such as parking collisions or the like, the
deceleration forces are small and short, while with more powerful collisions
the deceleration forces are allowed to act upon the shock-absorbing and
deformable parts of the vehicle during a relatively longer period of time.
By sensing the duration and magnitude of the deceleration a measure is
consequently obtained of how serious the collision is.
The invention will now be described in more detail with reference
to the attached drawing showing a preferred embodiment oE the invention.
~igures 1 and 2 are sectional views of an embodiment oE the device
according to the invention, Figure 1 showing said device in rest position
and Figure 2 showing said device when it is subjected to deceleration
forces that are exceeding a predetermined value. Figure 3 is a vertical
view of a cup spring being part of the device of Figures 1 and 2. Figure 4
is a sectional view taken along the line IV - IV of Figure 3 and illustrates
in more detail said cup spring in a first position. Figure 5 shows the cup
~-2-
:"` ~D87~D3~
spring according to Figure 4 in a second pos~itian.
The device according to Figures 1 and 2 shows a cylindrical ~ousing
1 rigidly connected to a vehicle ~not shown), said housing includ;ng a cyl- :~
inder 2. A mass body in the form of a piston 3 provided with a piston rod 4 ;-.:
is, against the action of a soft spring 5, movable downwards in said housing .
1 from the position s~own ;n Figure 1 to the position shown in Figure 2
Said piston rod 4 is dlsplaceable through an opening in the housing 1 and
is ~in a
. ~ -2a-
~87~3~
way not shown here) connectable to means affeeting the tightening of the
bands of the safety harness.
A mass body in the form of a piston 6 concentrically arranged
around the cylinder 2 is, against the action of a rigid spring 7, movable
downwards in the housing 1 from the position shown in figure 1 to t~eposition
shown in figure 2. The spring 7 is so dimensioned that the piston is able to
move only if the vehicle is given a deceleration of a predetermined
magnitude.
A cup spring 8 with locking tongues 8a extends through an opening
in the cylinder wall 2 in such a way that the locking tongues 8a in the one
position of the cup spring can be brought into engagement with an annular flange9 of the piston 3 which, because of this, is prevented from moving inside
the cylinder 2. The cup part 8b of the spring 8 extends into an annular
recess 10 of length d disposed in the piston 6. The recess 10 is provided
with an annular rim 11 which acts upon the cup part 8b upon movement of the -
piston 3.
The cup spring 8 is shown in more detail in figures 3-5. The
spring consists of an annular, arched cup part 8b, which in a known way can
be made to take two different positions. The inner periphery of the cup
part is provided with six locking tongues 8a forming a suitable angle, for
instance about 90 degrees, with the arched surface of the cup part. The
locking tongues and the cup part are preferably, but not necessarily, made
in one piece.
Figures 4 and S illustrate in more detail theeappearance of the CUp
spring in the two different positions said spring can take. In the position
shown in figure ~, see also figure 1, the locking tongues 8a are bearing
against the flange 9 of the piston 3. In the position shown in figure S,
see also figure 2, the cup part 8b has been brought to snap over into its
second position~ and as a consequence of this the locking tongues are bent
-- 3 --
~1~87(33~
outwards in the direction away from the centre of the cup spring.
The deceleration direction of the device has been indicated in the
figures with an arrow 12.
When deceleration forces of a predetermined magnitude do occur,
the mass body 6 will move downwards. If however, theedeceleration forces are
of short durat~on, the mass body 6 will not have time to move downwards far
engugh to affect the cup part 8b of the cup spring 8. Thus, when the
deceleration forces stop~ the spring 7 will return the mass body 6 to the
position shown in figure l without the cup part 8b being affect@d. Upon
prolonged deceleration of a certain magnitud~, however, the mass body 6 will
have time to move downwards, mainly corresponding to the distance d, until
the upper rim 11 of the recess 10 will push the cup part 8b down, causing
said part to snap down into the position shown in figures 2 and 5 so that -
the locking tongues 8a will be brought out of engagement with the mass body
3. If the deceleration is continued after this, the mass body 3 can now
mo~e in the deceleration direction 12 against the action of the spring 5
as is shown in figure 2. The movementoof the piston rod 4 can, as haseb~en
indicated above, in known manner be used to affect means for tightening
the bands of the safety harness.
:
