JPS5946190B2 - Emergency locking seat belt retractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a frame, a reel supported on the frame via a reel shaft, a seat belt fixed to the reel and retractable as the reel rotates, and a seat belt for retracting the seat belt. The present invention relates to an emergency seat belt retractor equipped with a take-up spring that biases the reel in the direction and a locking device that locks the reel to the frame in an emergency.

For example, this type of emergency locking seatbelt is
It is described in No. 72737 (Japanese Unexamined Patent Publication No. 57-1353).

In this emergency lock type seat belt, the inertia wheel is entrained by the cam plate during retraction, and if the belt is suddenly stopped while the belt is being retracted, the inertia wheel detaches from the cam wheel due to its own retraction inertia, and the cam plate The cam moves along the cam in the locking direction, that is, in the direction in which the ratchet teeth of the cam wheel and the ratchet teeth fixed to the case engage with each other. There is a disadvantage that the ratchet teeth may be crushed and, as a result, both ratchet teeth may continue to be in contact with each other, that is, lockup may occur.

It is an object of the present invention to provide an emergency locking seat belt retractor that eliminates this drawback.

The problem is that the locking device includes a cam wheel having first ratchet teeth fixed to a case, second ratchet teeth that are loosely fitted onto the reel shaft and can mesh with the first ratchet teeth in the locking direction, that is, in the axial direction. It consists of an inertia wheel that moves the cam wheel in the axial direction, and a first
In order to prevent interference between the ratchet teeth and the second ratchet teeth, there is a lock-up prevention plate that is provided axially outward of the inertia wheel and is rotatable relative to the inertia wheel, and a lock-up prevention plate that is fixed to the cam wheel and is connected to the long hole of the inertia wheel to prevent lock-up. A shaft pin is provided that protrudes through the long hole of the plate, and the shaft pin has a head size at its outer end that is large enough to be inserted through the long hole, and the lockup prevention plate is prevented from friction against the case. In the unwinding direction, the shaft pin is located between both ends of the elongated hole, and the shaft pin head can be inserted through the elongated hole, and in the winding direction, the lock-up prevention plate is caused by frictional contact with the case. This can be solved by moving relative to the rotational movement of the shaft pin and gripping the head of the shaft pin with its end face.

Next, the present invention will be described in detail with reference to the drawings showing embodiments.

As shown in FIG. 1, the emergency locking type seat belt retractor according to the present invention consists of a frame 1 having a square cross section, and side plates 1A and IB of the frame have concentric holes 1a and 1b. It is formed.

A reel 2 is rotatably supported through the reel shaft 3 in the holes 1a and 1b of the side plates IA and IB.

Therefore, the reel 2 and the reel shaft 3 are rotatably supported by the frame 1.

The seat belt 6 is fixed to the reel shaft 3.

A spring 51 biased in a direction to wind up the seat belt 6 is provided at one end of the reel shaft 3, and the spring is housed in the case 5.

The case 5 is fixed to one side plate 1B of the frame 1.

On the outside of the other side plate 1A of the frame 1, a ring-shaped first ratchet 7 is fixed concentrically to the hole 1a.

The center hole 7b of the first ratchet 7 is larger than the diameter of the reel shaft 3.

The first ratchet 7 and the side plate 1A are fixed by forming holes 1D in the end surface of the first ratchet 7 made of thermoplastic plastic, for example, in a plurality of holes 1D provided around the hole 1a of the side plate 1A, corresponding to the holes 1D. It is better to fit and weld the pins, but
Other known means may also be used, such as gluing or screwing.

Near the outer periphery of the outer end surface of the first ratchet 7, first ratchet teeth 7A are provided that project outward in the axial direction.

The first ratchet teeth 7A are formed to mesh with second ratchet teeth 8B, which will be described later, to prevent rotation of the reel shaft 3 in the unwinding direction.

The flange 3B of the shaft pin 3E protruding from the frame 1 on the first ratchet 7 side of the reel shaft 3 is fitted into a notch 3C formed in the shaft pin 3E in a mutually complementary manner. Rotates with 3.

A protrusion 3D that protrudes outward in the axial direction is provided near the outer edge of the flange 3B.

A cam wheel 8 is loosely fitted to the shaft pin 3E on the protrusion 3D side of the flange 3B.

A spring 14 is provided between the flange 3B and the cam wheel 8, and biases the flange 3B and the cam wheel 8 in a direction to separate them.

The cam wheel 8 is provided with second ratchet teeth 8B on the end surface on the flange 3B side, that is, on the first ratchet 7 side, which can mesh with the first ratchet teeth 7A.

The cam wheel 8 also has a hole 8D that loosely fits into the axial projection 3D of the flange 3B and guides it in the axial direction.

Therefore, the cam wheel 8 is connected to the flange 3B, that is, the reel shaft 3.
, and is slidable in the axial direction by the action of an inertia wheel 11, which will be described later.

A cam 8C is provided on the axially outer end surface of the cam wheel 8.

A cam 11B of an inertia wheel 11, which is loosely fitted to the shaft pin 3E, is in contact with the cam 8C.

A ratchet wheel 9 is loosely fitted on the outer periphery of the inertia wheel 11, so that the inertia wheel 11 and the ratchet wheel 9 can be relatively displaced in the rotational direction, but the amount of displacement is axially outward of the inertia wheel 11. It is regulated by the provided protrusion and a protrusion provided radially inward of the ratchet wheel 9.

In this case, the inertia wheel 11 and the ratchet wheel 9 are connected by a connection spring 10.

On the axially outer side of the inertia wheel 11, a lock-up prevention plate 12 is loosely fitted to the outermost end of the shaft pin 3E.

A snap ring 15 that engages with a circumferential groove 3G provided on the shaft pin 3E on the outside of the lock-up prevention plate prevents the lock-up prevention plate from falling off outward.

Spring 14 provided between flange 3B and cam wheel 8
Since the inertia wheel 11 is pressed against the lock-up prevention plate 12, these two members are frictionally interlocked.

However, since the friction material 18 is provided between the case 19 and the lock-up prevention plate 12, the lock-up prevention plate uses the frictional force of the friction material 18 to prevent the inertia wheel 11 from moving.
The movement is linked with a slight delay.

In this case, a shaft pin 21 is embedded in the cam wheel 8 in the axial direction.
, 24, and its head 21' is 11.20
stands out from

The diameter of the head 21' is larger than the diameter of the shaft pin 21 and smaller than the elongated hole 22.

Separately, the inertia wheel 11 is provided with an axially outwardly extending pin 23 which projects into a circumferentially extending elongated hole 25 provided in the lockup prevention plate 12.

The movement length d2 of the pin 23 within the elongated hole 25 is greater than or equal to the movement length 61 of the shaft pin 21 within the elongated hole 22, that is, d2
≧d1.

In this case, when rewinding, that is, when the lock-up prevention plate 12 rotates in the direction of arrow A, the pin 23 hits one part 25' of the long hole 25, and the other shaft pin 21 hits both ends of the long hole 22. It is located in the middle.

On the other hand, during winding, the shaft of the shaft pin 21 hits the end 2z of the elongated hole 22 of the lockup prevention plate 12, and the head 21' of the shaft pin 21 catches on the end surface of the lockup prevention plate 12.

Furthermore, an inertial sensing device 1 is provided below the ratchet wheel 9.
No. 3 pawl 13F is located.

An inertial body, ie, a ball 13D, is freely placed on the seat 13C of the case 13A of the inertial sensing device 13.

Case 1 has a dual-arm lever consisting of one lever that is always in contact with the lower side of the ball 13D and the other lever that is formed as a pawl 13F that can engage with the third ratchet tooth 9A.
It is pivoted to 3A.

When acceleration or deceleration occurs in the automobile due to a collision or the like, the ball 13D falls off the seat 13C due to its inertia, pushes down one of the double-armed levers, and pushes up the pawl 13F to move the third lever.
Engage with the ratchet teeth 9A.

In this case, the side plate 13B is located in the vertical direction, and the ball 13
When D is located on the seat 13C, the pawl 13F does not engage the third ratchet tooth 9A and the ball 13D is on the seat 1.
When the pawl 13F falls off from the third ratchet tooth 9A,
meshes with

The emergency lock type seat belt retractor according to the present invention functions as follows.

(1) When rewinding the seat belt; When starting to rewind the seat belt, the lock-up prevention plate 1
2 moves relative to the rotational movement of the shaft pin 21 due to contact with the friction material 18, and as shown in FIG. It is located between both ends of the hole 22.

When the seat belt is returned at a speed that does not allow the inertia wheel 11 to rotate relative to the cam wheel 8, the inertia wheel 11 and the lock-up prevention plate 12 are carried by the pin 23 and move along with the cam wheel 8 in the arrow direction. Rotate in the direction.

Therefore, the seat belt 6 can be freely retracted.

However, in an emergency, the rotation of the inertia wheel 11 lags behind the cam wheel 8 due to the inertia of the inertia wheel 11 itself or because the inertia sensing device 13 works and its pawl 13F engages with the third ratchet tooth 9A.
Cam 11B of inertia wheel 11 acts on cam 8C of cam wheel 8 to push cam wheel 8 axially inwardly, causing second ratchet tooth 8B of cam wheel 8 to engage first ratchet tooth 7A.

Therefore, the cam wheel 8, flange 3B, and reel shaft 3 are locked, and the seat belt is prevented from being pulled out.

(2) When retracting the seat belt; When starting to retract the seat belt, lock-up prevention plate 1
2 moves relative to the rotational movement of the shaft pin 21 due to contact with the friction material 18, and the shaft of the shaft pin 21 hits the end 22' of the elongated hole 22 of the lock-up prevention plate 12, and the head of the shaft pin 21 21' is caught on the end surface of the lock-up prevention plate 12.

During winding, the inertia wheel 11 and the lock-up prevention plate 12 are carried in the direction of the arrow by the shaft pin 21 in this state.

Therefore, there is no problem with the seat belt being caught.

However, if the winding is suddenly stopped, the inertia wheel 11 tends to move in the direction of the arrow due to its inertia.

However, the head 21 of the shaft pin 21 provided on the cam wheel 8
' is caught on the lock-up prevention plate 12, so the inertia wheel is connected to the cam wheel 8 and the lock-up prevention plate 12.
It is clamped between the two and cannot move in the axial direction.

That is, the inertia wheel cannot rotate in the direction of the arrow and push the cam wheel 8 inward in the axial direction by its cam 11B.

Therefore, the second ratchet tooth 8B and the first ratchet tooth 7A
There is no engagement or interference at all.

In the embodiment of the present invention, an example was shown in which the axial pin 21 provided on the cam wheel 8 restrains the cam wheel 8 from moving in the lock direction, that is, inward in the axial direction.
Japanese Patent Application No. 72738 (Japanese Unexamined Patent Publication No. 57-1353) is formed so that 1 moves inward in the axial direction to lock in an emergency.
In the emergency locking type seatbelt retractor described in , similarly, the inertia wheel 11 is provided with a shaft pin 21, and the cam wheel 8 and the lock-up prevention plate 12 are provided with a long hole 2.
It is clearly stated that it also belongs to the technical scope of the present invention to penetrate the hole 2.

[Brief explanation of drawings]

FIG. 1 is a schematic axial cross-sectional view of an emergency locking seatbelt retractor according to the present invention, and FIG. 2 is a view of a lockup prevention plate and a friction material viewed from the direction of arrow A-A. 1...Frame, 2...Reel, 3.
...Reel shaft, 6 ... Seat belt, 7
A...First ratchet tooth, 8...Cam wheel, 8B...Second ratchet tooth, 11.
...Inertia wheel, 12 ... Lock-up prevention plate, 19 ... Case, 21 ...
Shaft pin, 21'...Shaft pin head, 22, 24.
... Long hole, 51 ... Winding spring.

Claims (1)

[Scope of Claims] 1. A frame 1, a reel 2 bearing on the frame 1 via a reel shaft 3, a seat belt 6 fixed to the reel and capable of being wound up as the reel rotates, and a seat belt 6 on which the seat belt is wound. In an emergency lock type retractor equipped with a take-up spring 51 that biases in the take-up direction and a lock device that locks the reel to the frame in an emergency, the lock device has first ratchet teeth 7A fixed to the frame 1. , a cam wheel 8 having a second ratchet tooth 8B that is loosely fitted onto the reel shaft 3 and can be engaged with the first ratchet tooth in the locking direction, that is, in the axial direction, and an inertia wheel 11 that moves the cam wheel in the axial direction. When the winding is stopped, the relative movement in the axial direction between the cam wheel 8 and the inertia wheel 11 is restrained, and the first
In order to prevent interference between the ratchet teeth 7A and the second ratchet teeth 8B, a pump-up prevention plate 12 is provided outside the inertia wheel 11 in the axial direction and is rotatable relative to the inertia wheel.
, fixed to the cam wheel 8 and inserted into the long hole 2 of the inertia wheel 11.
4 and a shaft pin 21 that protrudes through the long hole 22 of the lock-up prevention plate 12, and the shaft pin has a head 21' at its outer tip that is large enough to be inserted through the long hole 22. The lock-up prevention plate 12 is in frictional contact with the case 19, and in the unwinding direction, the shaft pin is located between both ends of the elongated hole 22, and the shaft pin head 21' can be inserted through the elongated hole 22. In the winding direction, the lock-up prevention plate 12 moves relative to the rotational movement of the shaft pin 21 due to frictional contact with the case 19, and holds the head 21' of the shaft pin at its end surface. The emergency locking type seat belt retractor-02 is characterized in that the relative movement in the rotational direction between the lock-up prevention plate 12 and the inertia wheel 11 is restricted by a long hole 25 provided in one of them and a pin 23 provided in the other. Emergency locking seat belt retractor 63 case 19 and lock-up prevention plate 1 according to claim 1
2 are in frictional contact with each other via an elastic friction material 18.