FR2647398A1 - SECURITY BELT REEL - Google Patents

Abstract

A seat belt retractor is disclosed. It relates to a winder which comprises a main winding spring 34 placed between a frame 11 and a shaft 14, 15 carrying a roller and an auxiliary spring 36 coupled between the frame 11 and a clutch wheel 41. According to the In accordance with the invention, the clutch wheel 41 is coupled to the shaft 14, 15 by an elongated flexible coupling member 51 spirally wound around a portion 15 of the roller shaft so that it tightens when the shaft rotates in the direction of strap unwinding relative to the clutch wheel and loosens when the shaft rotates in the other direction. Application to motor vehicle seat belt retractors.

Description

2647398 -

  The present invention relates to a belt reel

security.

  Many embodiments of a vehicle seat belt retractor having a webbing winding mechanism which exerts a relatively large rotational force on the webbing winding roll when unrolled and a relatively low rotational force on the roll when the strap is connected to the buckle, have been proposed recently. These embodiments are intended to solve the problem of applying a sufficient force of rotation to the roll so that the strap

  rolled up without the strap pulled against the

  pant of the vehicle, when held by the belt, with a force such that it creates discomfort or even a lack of comfort. These reels usually have two

  winding springs coupled between the roller and the

  sis and a mechanism to disable one of the springs

  when the strap is hooked to the buckle.

  U.S. Patent No. 4,809,925 discloses and shows a seat belt retractor having a winding mechanism which has a main spring coupled between the roller and the spool, a clutch wheel supported by the roller shaft so that it can rotate, and an auxiliary winding spring

  coupled between the frame and the clutch wheel. A mechanism

  limited free movement mechanism arranged between the wheel

  clutch and the roller shaft allows rotation of am-

  predetermined amplitude of the roller shaft relative to the clutch wheel, but ensures the coupling of the shaft

  from the roller to the clutch wheel at one end of the

  limited free rein, so that the forces of the two

  spells act in parallel to ensure the winding of the strap on the roll. The limited free-moving mechanism allows the clearance of the strap to be eliminated when the auxiliary spring is deactivated and allows the strap to be removed when the occupant leans forward. The clutch wheel is locked and can not rotate in the winding direction by a mechanism of engagement with the clutch, consisting of a lever and a ratchet operated by an electromagnet which is energized when switch placed in the loop is closed after the introduction of the looping tab carried by the strap in the loop. The retractor described above has been entirely satisfactory and has worked reliably. On the other hand, it has been observed that the limited free displacement mechanism, comprising pinions and a locking pawl,

  created noise, and that noise, especially during

  strap and when the free movement is limited

  interrupted by winding the auxiliary spring,

  would confuse the occupant of the vehicle. The sound of gables and the sound of shock of the ratchet against the stop of

the wheel are thus undesirable.

  French Patent Application No. 2,478,471 describes and shows a seat belt retractor having a tension reduction mechanism in which a series of clutch disks act between the roller shaft and a clutch wheel and provide a mutual coupling with limited free movement. Collisions in numbers of up to five may occur during limited free movement when the trigger mechanism

  is disabled, and annoying noise is likely.

  The present invention aims at eliminating the problem posed by the noise of the rewinder described in FIG.

  United States Patent No. 4,809,925, with

  advantages of simplicity of construction, low cost and efficient and reliable operation. according to

  the invention, these characteristics are obtained by realizing

  A safety belt retractor similar in most respects to that of U.S. Patent No. 4,809,925, except for the elimination of the noisy mechanical clutch. The invention is characterized in that the limited free displacement coupling placed between the roller shaft and the clutch wheel is a

  flexible and elongated coupling member wound in a spiral

  Rally around a portion of the roller shaft and having a first end connected to the roller shaft and another end connected to the clutch wheel. The coupling member is wound in such a direction that it is tightened when the roller shaft rotates in the direction of the unwinding of the strap with respect to the clutch wheel and loosens when the shaft of the roller rotates in the winding direction of the strap relative to the clutch wheel. In addition to eliminating the problem posed by noise, the invention simplifies the reel by eliminating

  the clutch gear wheel, the idler gear and the ratchet.

  The mounting procedure is facilitated in a

ponding.

  Other features and advantages of the invention

  will be better understood by reading the description

  which will follow examples of embodiment, with reference to the accompanying drawings in which: Figure 1 is an exploded perspective of an embodiment of the invention; Fig. 2 is a side elevation of this embodiment with the cover removed and various parts torn off; Figure 3 is a section along the axis of the roller shaft as indicated by line X-X 'of Figure 2;

  FIGS. 4A, 4B and 4C are diagrams representing

  both the winding springs and the coupling member

respectively; and

  FIGS. 5A, 5B and 5C are diagrams representing

  both a linear analogy of the winding mechanism of this

  embodiment, at different stages of operation.

  The assembly 10 with chassis and roll of the winder comprises a U-shaped frame 11 having two parts 11a and 11b forming side walls and a retaining member 12 fixed to the left side wall 11a, an opening 11c

  being formed in the wall 11a of the frame 11 and being used

  as a reference point of reference. A sleeve 13 is mounted in the opening formed in the right side wall 11b of the frame 11. The shaft 14 of the main roller passes into the sleeve 13 and into a sleeve portion 12a formed in the retaining member 12. A ratchet wheel 14a for a blocking device in case of emergency (no

  shown) is formed at the right end of the shaft 14.

  A coupling shaft is coupled to the end square portion 14b of the shaft formed at the left end of the main shaft 14 so that the coupling shaft and the main shaft rotate together. A roll 1 of strap

  fits on the main shaft 14 between the side walls

  11a and 11b of the frame 11, and the end of a strap B (Figures 2 and 3) is fixed by a holding member 16a formed in the core of the web roll 16. A throat 15a

  is placed at the left end of the coupling shaft

  and houses the inner end of the main spring 36

  winding, as shown below.

  A detection assembly 20 (schematically represented

  2) has the tongue (not shown in FIG.

  attached to the strap B of the belt, the buckle (not shown) to which the tongue is attached so that the belt is closed, and a suitable circuit 21 which

  detects when the loop and the tongue are connected

  Tees. When the tongue is inserted into the loop, it comes into contact with a switch 22 placed in the loop and closes it, and a representative electrical signal

  the connection of the tongue and the loop is trans-

put by the circuit 21.

  A webbing roll control mechanism 30 in the winding direction includes a cover 31 secured with the retaining member 12 to the side wall 11a of the frame 11. A chamber 32 on the left side of the cover 31 houses a spring winding auxiliary spiral 34 whose outer end is in contact with the stop member 33 placed in the chamber 32. A second housing 35 covers the chamber 32 and has a second chamber 35a on the left side. The main spring 36, the outer end cooperates with the abutment member 35b placed in the second chamber 35a, is housed in the latter. A cover 27 covers the

second chamber 35a.

  The auxiliary spring 34 is fixed at its inner end to a member 41c of abutment of the clutch wheel 41 so that it remembers the wheel 41 in rotation in the winding direction of the strap. The main spring 36 is secured at its inner end to a groove 15a formed in the coupling shaft so that it recalls the roller 16

  in the winding direction of the strap.

  The clutch wheel 41 is part of a mechanism 40

  clutch which deactivates the auxiliary spring 34 (that is,

  that prevents rotation of the clutch wheel under the action of the auxiliary spring) when the strap B is connected to the buckle. The clutch wheel 41 is mounted so that it can rotate on the reduced-diameter end portion of the coupling shaft 15. When the tongue of the belt is connected to the buckle and when the electrical signal is transmitted by the device 20 (Figure 2), an electromagnet 46 is energized and pulls the plunger 46a of the electromagnet to the left in Figure 2. A coupling pin 46b mounted on the plunger 46a acts against a cam slot 44a formed in an arm of the lever 44 which is mounted in articulated form on an axis

  43 of pivoting carried by the retaining member 12. A customer

  45 which is mounted on the end of the lever 44 of

  in such a way that it can only rotate in the direction

  milking clockwise cooperates with a tooth 41a of the circumference of the clutch wheel 41 when the lever 44 pivots in the direction of the arrow H after control of the electromagnet 46, so that when the pawl 45 is in contact with a tooth 41a, the clutch wheel 41 stops rotating in the winding direction of the strap (counterclockwise) under the action of the restoring force of the spring auxiliary. On the other hand, the ratchet wheel teeth 41a allow the clutch wheel 41 to rotate in the direction of unwinding of the strap when it is extracted (as described below), the ratchet 45 pivoting in the counterclockwise despite the force exerted by a spring of

  recall (not shown), despite the excitement of electro-

  magnet and the pivoting of the lever 44 in the contact position

  pawl 45 with the clutch wheel. When the electro-

  magnet 46 is de-energized, a return spring 47 pushes the plunger to the right and pivots the lever 44 counter-clockwise so that the pawl 45 can no longer cooperate with the teeth 41a of the wheel. clutch 41. The mechanism 42 for cooperation with the clutch (elements 43 to 47) is mounted between the

  box-31 and the retaining member 12, below the mechanism

  strap winding (Figures 2 and 3).

  The clutch mechanism 40 is coupled to the shaft 15

  by a coupling 50 with limited free movement. Lake-

  Coupling 50 is a ribbon 51 which is spirally wound around the large diameter portion 52 of the coupling shaft. A loop 51a of the inner end of the ribbon 51 is attached to a tab 15b of the shaft 15, and a loop 51b of the outer end is attached to a tab 53 protruding from the clutch wheel 41. The ribbon 51 must be made of a flexible material with high tensile strength and low elongation. For example,

  films of polymeric materials such as "nylon", poly-

  esters and acetates, can be used.

  Some of the provisions of the elements are now

  described with reference to the direction of webbing unwinding

  (indicated by the arrows of FIGS. 4A to 4C). (a) The

  main fate 36 is arranged so that it is tight when the shaft 15 rotates clockwise and pulls the strap. (b) The auxiliary spring 34 is arranged to be tightened when the clutch gear 41 rotates clockwise. (c) The ribbon 51 is arranged to be clamped only when the shaft 15 and the pinion 41 rotate in opposite directions relative to each other, for example when the wheel 41 is at rest while the 'tree 15 turns alone in the direction

  clockwise. (d) When the ratchet 45 of

  clutch is in contact with a tooth 41a of the wheel

  clutch, this wheel 41 can turn clockwise but can not turn in the

  counterclockwise direction.

  Then, we describe the operation of a mode of

  embodiment of the invention having the pre-construction

cedente.

  Winding the webbing on the roll.

  The coupling shaft which is always biased by the main spring 36 in the winding direction of the strap, rotates counterclockwise under the action of the force of the main spring 36 and causes the rotation of the roller 16 in the same direction

  through the shaft 14 so that the strap B ,.

  when not coupled to the loop, is wound on the roller 16. In addition, the electromagnet 46 is de-energized and the plunger 46a is pulled out by the return spring 47. The pawl 45 of the pivoting lever 44, under these conditions, is maintained in the position in which it is not in contact with the teeth 41a of the clutch wheel 41. Accordingly, the clutch gear 41 rotates in the opposite direction of the needles of a watch under the action of the restoring force of the spring 34 and removes any play in the ribbon 51 during its rotation. Thus, the tape 51 is wound intimately around the outer surface of the coupling shaft and is stretched between the shaft 15 and the support member 53 on the clutch wheel 41. As a result, the biasing force of the auxiliary spring 34 in the winding direction of the strap is applied to the shaft 15 by

  ribbon 51, as schematically

  shown in Figure 5A. The strap is rolled up on the

  roll under the action of the combined forces of the main spring

  cipal and auxiliary spring acting in parallel.

  Sequence of the strap when it should be used.

  When the passenger pulls the strap B for use

  the roller 16, the main shaft 14 and the coupling shaft 15 (hereinafter referred to as "main shaft 14, etc.") rotate in the direction of the strap unwind (direction

  clockwise) with tightening of the main spring

  cipal 36 through the throat 15a of the shaft 15 and simultaneously with clamping the auxiliary spring 34 through the tape 51 which is stretched. This tension can be formally represented as corresponding to the result of a pull to the right of the strap B under the conditions of FIG. 5A, that is to say that the strap B is pulled despite the restoring force of the two springs 34 and 36, the ribbon 51 being stretched so that it transmits the force output to the strap to

  from the shaft 14, etc., to the clutch wheel 41.

  The passenger connects the strap to the buckle.

  When the passenger couples the tongue of the strap B to the loop, the switch 22 of the buckle closes and controls the electromagnet 46 which pulls the plunger 46a inwardly and rotates the lever 44 in the direction of the arrow A in FIG. 2. As a result, the pawl 45 is in contact with a tooth 41a of the wheel 41, it blocks the wheel 41 by preventing its rotation in the unwinding direction of the strap, and it maintains inert state the auxiliary spring 34 in the winding direction of the strap (deactivation of the spring 34), these conditions being

illustrated in Figure 5B.

  The passenger releases the strap after connecting to the buckle.

  When the passenger couples the tongue of the

  ture B to the loop, he must naturally manipulate the loop to pull a longer length than the one that

  is necessary for the normal passage around his body.

  Consequently, when he releases the strap after the

  from the tongue to the buckle, the strap is re-locked

  by the force of main spring 36 alone, until

  that the strap fits the body. The strength of the spring

  34 acting in the winding direction is not applied to the shaft 14, etc. because wheel 41 can not

  turn and is locked in the winding direction.

  When the strap B was unwound, the ribbon 51 was stretched between the wheel 41 and the shaft 15 and wrapped around it. When the shaft rotates to remove play in the strap, the main shaft 14, etc. rotate counterclockwise under the action of the sole force of the spring 36, these conditions being shown in Figure 5C. The rotation of the shaft 14, etc. counterclockwise, relative to the fixed clutch wheel 41, loosens the turns of the ribbon 51 around the shaft 15. As the auxiliary spring 34 is de-energized and as the pressure applied to the body is only that resulting from the force of the main spring 36, the strap does not reduce the comfort of the passenger.

The passenger leans forward.

  When the passenger leans forward from his normal sitting position, strap B unfolds and tends

  only the main spring 36 until the quantity

  additional strap that was unrolled at the time of the buckling of the strap was unrolled. When this

  additional length was unwound, ribbon 51

  rolls around the shaft 15 and stretches between the wheel 41 and

  the shaft 15; in other words, the free movement

  between the shaft 15 and the wheel 41 is completed. This tendency

  sion causes rotation of the wheel 41 in the direction of clockwise. The teeth 41a of the wheel 41 can

  move in front of the ratchet 45 which deviates elastically

  and does not prevent rotation of the wheel 41. As a result,

  when the strap B is pulled beyond the

  mentioned above (the free movement due to the

  removal of the strap's play after the buckling of the strap

  ci), the strap B is removed and tends the two springs

Auxiliary and Principal 34 and 36.

  The passenger resumes the normal sitting position.

  When the passenger returns to his normal sitting position after leaning forward, the strap B winds up only under the action of the mainspring force

  36, for the reason already described with reference to the deletion

  sion of the game of the strap after its closure, because the teeth 41a. of the wheel 41 hold the pawl 45 in these circumstances and prevent the rotation of the wheel 41 in the winding direction of the strap (contrary direction of

Clockwise).

  The passenger separates the tongue from the buckle.

  When the tongue of the belt is separated from the loop, the switch 22 placed in the loop opens and the electromagnet 46 is de-energized. As a result, the plunger 46a returns to the advanced position under the action of the return spring 47 and rotates the lever 44 counterclockwise (direction opposite that of the arrow H of FIG. 2) , with removal of the cooperation of the teeth 41a of the wheel 41 and the pawl 45. As a result, the wheel 41 rotates rapidly in the winding direction of the strap (contrary direction of

  clockwise) under the action of the force of

  auxiliary fate 34 and wraps the ribbon 51 in the stretched state.

  The seat belt retractor of the prior art

  creates an annoying noise at this stage of operation (ie the removal of free movement in the

  gear train coupling the clutch wheel to the shaft).

  On the contrary, a safety belt webbing retractor

  according to the invention has a construction which allows free movement between the shaft 14, etc. and the clutch wheel 41 by tensioning and loosening a spirally wound flexible member (ribbon 51) placed between the shaft 15 and the pinion 41. This tightening and loosening of the tape creates virtually no noise and the appearance

  mechanical noise is removed.

  In the variants, the clutch mechanism can obviously be formed with any device other than the structure shown in the accompanying drawings. In addition, the device for detecting the coupling and uncoupling states of the tongue and the loop can also be used as a detection device in a

  an alarm circuit intended to inform the passenger of a

  suitable cord from the tongue to the buckle.

  Accordingly, the invention relates to a seat belt webbing retractor which has stable operation and which exerts a sufficient winding force of

  the strap so that it is rolled up without the pas-

  sager feels excessive pressure when

  the strap is normally applied over his body. The enrou-

  their does not create annoying mechanical noise when the limited free movement between the roller and the clutch is traveled in one direction (loosening of the ribbon) and in the other direction (tightening of the ribbon), for the deactivation of the

auxiliary spring.

  Of course, various modifications may be made by those skilled in the art reels that have just been described as non-limiting examples

  without departing from the scope of the invention.

Claims (1)

CLAIM   Seat belt retractor, of the type which   a roller (16) carried by a shaft (14) is taken so that it can rotate in a frame (11), a main winding spring (34) coupled between the chasis and the roller shaft and reminding the tree in the sense   winding of the strap, a clutch wheel (41)   on the roller shaft so that it can turn, a   auxiliary winding spring (36) coupled between the casing   sis and the clutch wheel and recalling the clutch wheel in the winding direction, a device (42) maneuvering   clutch to prevent rotation of the wheel   clutch in the winding direction of the strap when connected to a loop, and a limited free movement coupling device (50) placed between the   clutch wheel and the roller shaft and intended to accommo-   plowing the clutch wheel to the roller shaft for a selected rotation of the roller shaft rotation relative to the clutch wheel in the direction of unwinding of the strap, while allowing the rotation of the roller shaft relative to the clutch wheel in the winding direction of the strap, under the action of the return force of the main spring when the wheel can not rotate in the webbing winding direction, characterized in that the limited free-movement coupling (50) is a flexible and elongate coupling member (51) wound spirally around a portion (15) of the roller shaft and having a first end (51a). connected to the roller shaft and its other end (51b) connected to the clutch wheel (41), the coupling member (51) winding in the clamping direction when the roller shaft (14) , 15) rotates in the direction of unwinding of the strap with respect to the clutch wheel (41) and in the direction of the sling when the roller shaft (14, 15) rotates in the webbing winding direction with respect to the clutch wheel (41).