Automatic safety-belt reeling device

An automatic passenger seat safety belt reeling device, has a steel frame (31, 32, 33) and a reel rotatable in the frame about an axis (39) which is angularly moveable about a second axis (40) offset from the first axis to effect locking of the belt, the first axis being coupled by connecting links (48) to a pivot (46) of a clamping member (47), the clamping member being thereby moveable with the angular movement of the axis (46) of the reel about yet a further axis (45) displaced from the pivot (46), the clamping member having a curved clamping surface (47a) which thereby moves towards a paying-out seat belt (61) to lockingly clamp it against a clamping plate (50) located in the frame.

The invention relates to an automatic safety-belt reeling device more 
especially a device having a frame having a back and two side parts within 
which a belt reel is carried rotatable about a first axis and being 
effective to permit pay-our or reel-in of the belt, a multifunction sensor 
mechanism operable to effect locking of the reel rotation during pay-out 
from said reel between said side parts of said frame and said first axis 
being displaceable about a second axis parallel thereto to initiate 
locking of the belt. 
An automatic safety-belt reeling device which is known for example from DE 
37 18 877 A1, has a clamping member which is arranged on the frame to 
swivel towards a counterclamping surface in the frame, the blocking 
mechanism and the sensor mechanism executing a linear lifting movement. 
In a further automatic safety-belt reeling device known from EP 0185 367 
A2, a clamping action is effected by a one-sided lifting action, about a 
point of rotation, of the reel axis. 
In each of the prior arrangements the device is relatively frictional and 
the present invention seeks to provide an improved automatic safety-belt 
reeling device, of simple construction whilst providing rigidity of 
operation and synchronised actuation of a clamping member with low 
friction and accurate symmetry of operation. 
In accordance with the present invention there is provided an automatic 
safety belt reeling device having a frame with a back and two side parts 
within which a belt reel is carried rotatable about a first axis, rotation 
about said axis being effective to permit pay-out or reel-in of the belt, 
a multi-function sensor mechanism operable to effect blocking of the reel 
rotation during pay-out from said reel between said side parts of said 
frame, said first axis being displaceable about a second axis parallel 
thereto to initiate locking of the belt characterised in that for said 
locking of the belt there is provided a moveable belt clamping member 
guided for movement in the frame about a third axis parallel to the first 
axis, said clamping member having a first clamping surface and said belt 
passing between said first clamping surface and a second opposing clamping 
surface carried by the frame, and a link directly pivotally linking the 
first axis of the reel to a further axis of the clamping member at a point 
which is nearer to said first surface than is the third axis whereby 
movement of the reel about said second axis during pay-out of the belt 
results in angular movement of the clamping member about the third axis 
moving said clamping surface into engagement with the belt to effect 
clamping thereof between said surfaces. 
In the case of this automatic safety-belt reeling device, during the 
lifting movement of the clamping member exact parallel guidance of the 
reel axis with regard to its swivel axis is ensured together with rigid 
parallel actuation of the clamping member when actuated. 
Guiding of the third axis of the clamping member can be effected by arcuate 
guide slots in the side parts of the frame or by providing a separate 
supporting spindle for the clamping member. 
The necessary movement of the reel axis can preferably be effected by way 
of two parallel links, mounted on the reel axis, and on the two bearing 
pivots to which the clamping member is rotatably located and defining a 
fourth axis.

The safety belt reeling mechanism of FIG. 1 shows a reel 9 to pay out and 
reel in a safety belt 12 under tension of a clock spring (not shown). The 
safety belt 12 is wound onto reel 9 in known manner and the reel is 
rotatable about a first axis 8. The reel has flanges 16 and 17 at 
respective ends and is arranged in a frame having a back and parallel 
sides 1 and 2 and which is fastenable to a vehicle chassis or door pillar. 
The mechanism also has a sensor mechanism, FIGS. 4-7, which responds to 
the vehicle rate of change of speed or belt rate of change of speed to 
initiate a lock up action. 
Mounted between the frame sides but separately to the belt reel 9 is a 
clamping mechanism which has a clamping jaw 3 with coaxial bearings 4, 5 
at respective ends formed by protruding ends of a bearing pin 13 which is 
inserted into a bore of the clamping jaw 3. The clamping jaw 3 is mounted 
so as to be freely swingable on the bearing pin 13, the protruding ends, 
forming the bearings 4, 5, being guided in clamping-jaw guides in the form 
of arcuate slots 6 and 7 in the frame sides 1, 2. These slots curve 
circularly about an axis 27 as shown which lies outside the frame limbs 1 
and 2 but alternative curve shapes may be chosen if desired for such 
slots. 
The clamping jaw 3 has teeth 30 on its clamping surface arranged in rows 
which extend across the direction of movement of the safety belt 12, on 
the clamping surface of the clamping jaw 3. The design of these teeth 30 
is chosen to suit the weave and material of the safety belt 12, so that 
they can suitably lock into one side of the fabric. 
On the other side of the safety belt 12 is a member 11 which is mounted on 
the central or back part 19 of the frame. Integrally formed into the back 
part 19 of the frame are ascending wedge surfaces 20, 21 and 22 against 
which the counter-clamping bearing 11 butts. The angle at which these 
wedge surfaces form with the direction of movement of the safety belt 12 
is preferably between 2.degree. up to 10.degree.. 
The first winding axis 8 of reel 9 is mounted to be able to swing about a 
parallel second axis 10 on two levers 28, 29, of identical length, the 
axis 10 being fixed on the two frame limbs 1 and 2. This second axis 10, 
the first axis 8 and the axis of the bearing pin 13 are held all parallel 
to one another. The axis 8 and the two levers 28 and 29 as well as the 
swivel axis 10 can be provided as described in greater detail in the 
Specification of European Patent Application Number 88302921.7. The reel 
axis 8 and the swivel axis as well as one of the two levers 28 and 29 can 
be formed by a U-shaped bearing needle member and the other of the two 
levers 28 and 29 is provided by appropriate design of a multi-function 
deceleration sensing assembly. The two levers 28 and 29 are designed to be 
of identical length, so that an exact simultaneous and parallel guidance 
of the winding axis 8 about the swivel axis 10 upon a lifting movement, to 
be described in more detail below, into a locking position is ensured. 
As shown by FIG. 1, the first axis 8 is connected by way of a lifting 
linkage in the form of two parallel link member 14 and 15 to the 
protruding ends of the bearing pin 13 to form the bearings 4 and 5 of the 
clamping jaw 3 on the frame limbs 1 and 2. Moreover, the clamping jaw 
possesses supporting feet 31 and 32 which are supported, at least during 
lift movement, into the clamping position, against the end flanges 16 and 
17 of the winding reel. In this way control of engagement of the teeth 30 
with the belt can be achieved. The teeth lying furthest from reel can 
thereby be arranged first to engage the safety belt during locking 
operation. The control may however, be arranged if desired that the rows 
of teeth lying nearest to the reel are the first to enter into engagement 
with the safety belt 12. 
Referring now to FIG. 2, guide projections 23, 24 can be provided if 
required on the jaw 3 which protrude on each side of the belt 12 in the 
exemplified embodiment shown, into aligning apertures 25 and 26 of the 
counter-clamping bearing plate 11. 
In operation of the device shown in FIG. 1 the counter-clamping plate 11 
forms a fixed smooth guide surface for the safety belt 12. During free 
running action of the reel 9, the reel runs freely about its axis relative 
to levers 28 and 29. In the event of response of the sensor mechanism, to 
an accelerated belt-strap extraction movement or to abrupt vehicle 
deceleration, the reel 9 is locked to the levers 28 and 29 by the action 
of the mechanism and the winding axis 8 of the winding shaft of the belt 
reeling mechanism 9 is therefore swivelled about the second axis 10, by 
the force of the belt 12 pay-out of which is abruptly interrupted. This 
swivel movement is indicated by arrow A and results in the spindle 13 
carrying jaw 3 in a direction defined by guide slots 6 and 7 by virtue of 
link member 14 and 15. 
The clamping surface of the clamping jaw 3 with the teeth 30 therefore 
approaches the counter-clamping bearing 11 and brings the teeth firmly 
into engagement with the belt-strap part 18, lying between the 
counter-bearing 11 and the clamping jaws 3. 
In this way the run of the belt from the frame is halted and payout of belt 
12 from the locked winding shaft, (on which the belt can be wound 
relatively loosely), is prevented. 
Referring now to the preferred embodiment of the invention as shown in 
FIGS. 3-7, the automatic safety belt reeling device comprises a main frame 
having a back portion 31 provided with a substantial fixing boss 32 for 
fixing the frame to the door pillar of a vehicle body. The frame has two 
side parts denoted by references 33 and 34 provided with large apertures 
35 and 36 for accommodating the ends of a safety belt reel 37. The safety 
belt reel 37 is located on splines carried by a multi-function sensing 
device which is seen in the side views of FIGS. 4-7. The reel 37 and the 
multi-function sensing device are carried on a U-shaped supporting pivot 
needle denoted by reference 38. The limb 39 of the needle provides a pivot 
for rotation of the central splines of the multi-function sensing device 
and the limb 40 provides for pivotting of the multi-function sensing 
device and the reel 37. Thus the limb 39 defines a first axis of rotation 
of the reel and the limb 40 defines a second axis about which the reel 
axis 39 is able to angularly move whilst remaining parellel to 40. Thus in 
the assembled device, the limb 40 of the U-shaped member 38 is rotatable 
carried in apertures 41 and 42 of the side parts of the frame. Carried on 
a further spindle denoted by reference 43 carried in apertures 44 and 45 
of the frame, there is a clamping member 47 which has a through-bore 45 to 
receive spindle 43. The clamping member 47 is also provided with apertures 
such as 46 on each side which are located nearer a clamping surface 47a of 
the clamping member than the aperture 45 about which the clamping member 
rotates. The apertures 46 provide for location of upper pivotal ends of 
respective links 48, the lower ends of which are rotatably carried on 
respective spigots such as respective concentric spigot 49 on each end of 
the belt reel 37. 
The surface 47a of the clamping member 47 is provided with moulded-in 
serrations which extend along the surface thereof transverse to the 
direction of pay-out of the seat belt as seen in FIGS. 4-7 and fixed 
within the back part 31 of the frame there is a moulded clamping plate 
denoted by reference 50 in FIG. 3. This clamping plate is provided with 
moulded-in recesses to receive two inwardly projecting ridges 51 as seen 
in the back part of the frame thereby acting to positively locate the 
clamping plate 15 against movement in the direction of travel of the seat 
belt. 
Referring to FIG. 4, a side view of the assembled belt reeling device is 
shown with the outer cover of the multi-function sensing device partially 
cut away to reveal the interior of the cam-operated belt acceleration 
sensing device denoted generally by reference 51 and also the device 
denoted generally by reference 52 which senses excessive deceleration of a 
vehicle on which the reeling device is carried, in any direction. As seen, 
the latter comprises a pawl which is displaceable by an inertial mass 
comprising a ball 54. 
The assembly of the multi-function sensing device is held in its unoperated 
condition by a spring denoted by reference 53 one end of which bears 
against the housing of the multi-function sensing device and the other end 
of which is located in a fixed position to the frame. 
The multi-function sensing device is substantially as described in the 
Specification of European Patent Application 88302921.7 which describes 
the use of a U-shaped support needle member such as 38. Further details of 
deceleration and or belt acceleration sensing means are given in the 
Specification of European Patent Application Number 83302158.7 and U.K. 
Patent Application Number 8628148. In each case, the mechanism is designed 
to effect lock-up of the belt reel in an emergency condition. 
It will be appreciated that in the present instance, lock-up of the belt 
reel 37 is effected by the multi-function sensing device whereby the 
sensing device and the belt reel are locked together to cause the axis of 
the belt reel defined by the limb 39 of the U-shaped support member to 
rotate about the second axis defined by the limb 40. Such movement is thus 
transmitted via the respective links 48 to the pivot point 46 of the 
clamping member 47 whereby the curved clamping face 47a of the clamping 
member 47 is rotated about the pivot axis defined by the pin 43 and the 
clamping face moves towards the seat belt 61 thereby clamping it against 
the inner surface of the clamping plate 50. After initial engagement of 
the first few teeth or serrations of the curved clamping surface 47a with 
the paying-out seat belt 61, the clamping force acting to lock the seat 
belt 61 between the clamping surface 47a and the clamping plate 50 is 
generated substantially entirely by the action of the belt 61 itself and 
the reaction exerted by the spindle 43. Typically, the clamping force 
exerted between the clamping surface 47a and the belt 61 is equivalent to 
2 or 2.5 times the tension in the belt 61 itself. 
Referring now more particularly to the operation of the device as 
illustrated in FIGS. 4, 5, 6 and 7, FIG. 4 shows the normal free-running 
operation position of the total assembly at which position the belt 61 is 
free to move inwardly or outwardly of the assembly. During withdrawal, of 
the belt 61 the reel 37 pays out the belt and at the same time winds up a 
clock spring not shown the force of which then acts to recoil the belt 
presenting a comfortable tension thereon against the occupant of the seat 
in conjunction with which the belt is used. 
Referring now to FIG. 5, it is assumed here that the vehicle is subject to 
an excessive deceleration and the effect of this is to cause movement of 
the ball 53 thereby commencing to lift the pawl of the multi-function 
sensing mechanism into engagement with the outer toothed periphery of the 
ratchet toothed wheel 55 which rotates with the reel in relation to the 
remainder of the mechanism. The mechanism is thereby locked up to cause 
rotation of the reel axis 39 in relation to the second axis 40 and 
assuming that there is substantial tension on the belt 61 at this time, 
the belt reeling device moves into a condition indicated by FIG. 7 wherein 
it is seen that a substantial proportion of the curved clamping surface 
47a of the clamping member 47 is in engagement with the belt 61 having 
rotated about the spindle 43 after being picked up by the belt. 
A similar effect will result as indicated in FIG. 6. The inertial member 56 
which is responsible to excessive reel-out speed change, is moved into 
engagement with the inner teeth 57 of the toothed wheel, which again 
causes the multi-function assembly to be locked from the point of view of 
rotation, to the reel 37 and the result is the same as shown in FIG. 7 
referred to above. 
In each case, when the locking tension is released from the belt the spring 
53 and the clock spring of the reel acts to urge the reel and the 
multifunction arrangement about axes 39 and 40 respectively to enable the 
clamping member to be returned to its initial condition as shown in FIG. 
4.