Buckle and seat belt device

Abstract

Provided are a buckle that can achieve size reduction while keeping costs low, and a seat belt device including the buckle. A buckle 10 includes: a base 11; a latch member 12 having a claw portion 12d that engages with a tongue; a slider lock member 14 for preventing movement of the latch member 12 in a latch release direction when the tongue and the latch member 12 are latched; a slider spring 17 compressed between the slider lock member 14 and the latch member 12; an ejector 15 for detaching the tongue; and an ejector spring for biasing the ejector 15 in a direction of detaching the tongue. The ejector spring has an ejector spring 18a and an ejector spring 18b arranged in parallel at the center in the transverse direction of the base 11.

Description

Buckle and Seat Belt Device

[0001] The present invention relates to a seat belt device equipped on a seat of an automobile or the like and a buckle for this seat belt device.

[0002] Generally, vehicles such as automobiles are provided with a seat belt device that restrains an occupant on a seat having a seat bottom (seat cushion) where the occupant sits and a seat back (seat back) located on the back of the occupant. The seat belt device includes a webbing that restrains the occupant, a retractor that winds up the webbing, a buckle disposed on the side surface of the seat, and a tongue movably supported on the webbing, and restrains the occupant on the seat by fitting the tongue into the buckle.

[0003] A conventional buckle has a latch member that enters a locking hole of an inserted tongue to lock the tongue, an operation button that disengages the latch member from the locking hole of the tongue to release the locking with the tongue, an ejector that presses the tongue in a direction to disengage from the buckle when the latch member releases the locking with the tongue, and an ejector spring that constantly biases the ejector in a direction in which the tongue disengages from the buckle.

[0004] In order to generate a spring force required for buckle performance, an ejector spring having a certain length in the longitudinal direction is used, and the buckle is relatively long in its longitudinal direction (tongue insertion direction), making it difficult to miniaturize the buckle.

[0005] Patent Document 1 discloses a buckle in which a first ejector spring is disposed outside one side wall of a base, a second ejector spring is disposed outside the other side wall of the base, and the length in the tongue insertion direction is shortened. However, since the ejector spring is disposed outside the side wall of the base, the size of the buckle in the short side direction (width direction) orthogonal to the tongue insertion direction has become large. In addition, additional parts are required to hold the ejector spring in the region outside the side wall of the base, increasing the cost.

[0006] International Publication No. 2012 / 081189

[0007] This invention has been made in view of the above-mentioned conventional circumstances, and aims to provide a buckle that can reduce size and cost, and a seat belt device equipped with this buckle.

[0008] The buckle of the present invention comprises a base having a bottom and a pair of side walls rising from a pair of side edges of the bottom; a latch member rotatably supported on the side wall between a non-latch position and a latch position, and having a claw portion that rotates to the latch position and engages with the tongue when the tongue is inserted into a predetermined position; a slider lock member that prevents the latch member from moving in the latch release direction when the tongue and the latch member are latched; a slider spring compressed between the slider lock member and the latch member; an ejector that releases the tongue; an ejector spring that biases the ejector in the direction of releasing the tongue; and a release button provided longitudinally movably on the side wall of the base, which presses the slider lock member during a latch release operation and allows the latch member to move in the latch release direction, wherein the ejector spring comprises a first ejector spring and a second ejector spring arranged in parallel in the short-direction center of the base.

[0009] In one aspect of the present invention, the first ejector spring and the second ejector spring are connected at one end.

[0010] The seat belt device of the present invention comprises a seat belt to be worn by an occupant, a tong movably supported by the seat belt, and a buckle of the present invention to which the tong is locked.

[0011] According to the present invention, the buckle can be made smaller and the cost can be reduced.

[0012] This is a parts diagram showing a buckle according to an embodiment of the present invention. This is a perspective view of the ejector spring. This is a cross-sectional view of the buckle in the tongue-disengaged state. This is a cross-sectional view of the buckle before latching begins when the tongue is inserted. This is a cross-sectional view of the buckle after latching has begun.

[0013] Embodiments of the present invention will be described below with reference to the drawings.

[0014] Figure 1 is an exploded view of a buckle 10 according to an embodiment of the present invention. As shown in Figure 1, the buckle 10 comprises a base 11 made of a U-shaped frame having a bottom and a pair of left and right side walls rising from a bottom and a pair of side edges, a latch member 12 rotatably supported on both side walls of the base 11 and having a claw portion 12d that can engage with the opening 5 (see Figure 4) of the tongue plate 4, a slider lock member 14 supported on the upper surface of the latch member 12 so as to be relatively movable and preventing the latch member 12 from moving in the disengagement direction when the opening 5 of the tongue plate 4 and the latch member 12 are engaged, and a slider spring 17 compressed between the slider lock member 14 and the latch member 12 and constantly biasing the slider lock member 14 toward the latch member 12. That is, the slider spring 17 is wound around a rod-shaped guide portion 14A at the lower end of the slider lock member 14 and loosely fitted into the guide hole 12c of the latch member 12.

[0015] Furthermore, the buckle 10 includes a lock pin 16 that is supported in holes on both side walls of the base 11 and presses against the upper surface of a slider lock member 14 that prevents the latch member 12 from moving in the disengagement direction when the tongue plate 4 and the latch member 12 are engaged; a buckle button 13 that functions as a release button and is provided longitudinally movably on both side walls of the base 11; and an inertia lever 19 that is located between the buckle button 13 and the latch member 12 and is rotatably supported in grooves on both side walls of the base 11. The inertia lever 19 has a round pin-shaped lever-side engagement connecting portion 19a with a circular cross-section.

[0016] Furthermore, the buckle 10 includes an ejector 15 slidably mounted on the bottom of the base 11 in the longitudinal direction of the base 11 to detach the tongue plate 4 from the buckle 10, ejector springs 18a and 18b that constantly bias the ejector 15 in the direction of detaching the tongue plate 4 from the buckle 10, and an upper cover 20 and a lower cover 21 that enclose them so as to cover them from above and below.

[0017] Two ejector springs 18a and 18b that bias the ejector 15 are arranged in parallel in the center of the base 11 in the short direction. One end of each ejector spring 18a and 18b abuts against the ejector 15, and the other end abuts against the bottom of the base 11. The ejector springs 18a and 18b may be separated as shown in Figure 1, or one end may be connected as shown in Figure 2. By using an integrated ejector spring 18a and 18b as shown in Figure 2, it becomes easier to maintain the distance between the two springs, and it is possible to prevent the springs from becoming entangled when the buckle is operated. If the spring seating surface is configured as a projection from the base 11, it is necessary to secure a clearance between the inner diameter of the spring and the base projection, and in order to prevent the springs from colliding, the distance between the two springs must be set larger, which imposes many constraints on the design of the buckle 10 in the width direction. By using integrated ejector springs 18a and 18b, the distance between the two springs can be kept constant, thus preventing entanglement while narrowing the gap. For example, SUS (stainless steel) can be used as the material for the ejector springs 18a and 18b. The wire diameter, pitch, and center diameter of the ejector springs 18a and 18b are set based on the required load.

[0018] Next, the engagement operation between the buckle 10 and the tongue plate, configured in this way, will be described. In the following description, "up and down" refers to the up and down position of the buckle 10 when it is mounted on the vehicle.

[0019] First, in the disengaged (disengaged) state of the buckle 10, where the tongue plate is not inserted, the ejector 15 is set to its upper limit position by the spring force of the ejector springs 18a and 18b, as shown in Figure 3. At this upper limit position of the ejector 15, the latch member 12 rotates upward (clockwise from the latched state) in relation to the slider lock member 14, the lock pin 16, and the slider spring 17. At this time, the slider lock member 14 is disengaged from the lock pin 16 and rotated to the right, the upper surface of the latch member 12 abuts against the lever-side engagement connection portion 19a of the inertia lever 19, and the rear surface of the latch member 12 abuts against the front surface of the lock pin 16. In this state, the latch member 12 is set to a disengaged position where its claw portion 12d is disengaged from the tongue insertion passage and does not engage with the tongue plate.

[0020] As shown in Figure 4, when the tongue plate 4 is inserted through the tongue insertion opening 20A provided at one end of the upper cover 20 of the buckle 10, the lower end of the tongue plate 4 comes into contact with the upper end of the ejector 15, and the ejector 15 is pressed downward. As a result, the ejector 15 moves downward while compressing the ejector springs 18a and 18b in response to the insertion of the tongue plate 4, so that the pressing parts 15a and 15b of the ejector 15 (see Figure 1) push downward the pressed parts 12a and 12b of the latch member 12 (see Figure 1), causing the latch member 12 to rotate counterclockwise.

[0021] As a result, the claw portion 12d of the latch member 12 enters the movement path of the tongue and fits into the locking hole 5 of the tongue plate 4, and the latch member 12 is in the engaged position. When the insertion force of the tongue plate 4 is released, the ejector 15 presses against the lower end of the tongue with the spring force of the ejector springs 18a and 18b, and the inner edge of the lower end of the locking hole 5 of the tongue plate 4 engages with the claw portion 12d, so that the tongue plate 4 is engaged with the buckle 10, and the tongue plate 4 and the buckle 10 are in the engaged state shown in Figure 5.

[0022] At this time, the spring force of the slider spring 17 causes the slider lock member 14 to enter between the rear surface of the latch member 12 and the front surface of the lock pin 16, and its rear surface is pressed against the lock pin 16. As a result, the slider lock member 14 holds the latch member 12 in the engaged position, so the latch member 12 does not come out of the locking hole 5 of the tongue plate 4, and the latch between the tongue plate 4 and the buckle 10 is firmly held.

[0023] To release the engagement between the tongue plate 4 and the buckle 10, the buckle button 13 is pushed downward, causing the buckle button 13 to move downward. The buckle button 13 then presses the slider lock member 14 downward, causing the slider lock member 14 to move downward against the biasing force of the slider spring 17 relative to the latch member 12. The slider lock member 14 then disengages from the lock pin 16, and the slider lock member 14 is no longer held in place by the lock pin 16. As a result, the slider lock member 14 and the latch member 12 rotate clockwise, and the claw portion 12d moves to the right. As the ejector 15 is biased in the disengagement direction by the spring force of the ejector springs 18a and 18b, the ejector 15 repels the latch member 12 to the right via the tongue plate 4, causing the latch member 12 and the slider lock member 14 to rotate further clockwise, and as the claw portion 12d escapes from the locking hole 5 of the tongue plate 4, the tongue plate 1 is pushed out upward.

[0024] When the latch member 12 contacts the lock pin 16, the clockwise rotation of the latch member 12 and the slider lock member 14 stops. At this time, the slider lock member 14 contacts the lock pin 16 due to the biasing force of the slider spring 17. Finally, the ejector 15 reaches its upper limit position, the latch member 12 reaches the disengaged position, and the buckle 10 enters a disengaged state with the tongue plate 4 separated (see Figure 3).

[0025] In this embodiment, the ejector 15 is constantly biased in the direction that separates the tongue plate 4 from the buckle 10 by two ejector springs 18a and 18b arranged in parallel. By using two ejector springs, the length of each spring can be shortened compared to the case of a single ejector spring, while still generating the spring force necessary to bias the ejector 15.

[0026] Since the short ejector springs 18a and 18b can be positioned in the center of the base in the short direction, the size of the buckle 10 in the short direction can be kept small while reducing its size in the long direction. In addition, no additional parts are required to hold the two ejector springs 18a and 18b, which reduces costs.

[0027] By using two ejector springs 18a and 18b, the required load per ejector spring is halved compared to the case with one ejector spring, thereby improving durability.

[0028] In the above embodiment, three or more ejector springs may be arranged in parallel, but it is preferable to use two, taking into consideration the standard dimensions of the buckle 10, etc.

[0029] In the above embodiment, the configuration of the buckle 10 other than the ejector springs 18a and 18b is merely an example and is not limited to the illustrated configuration.

[0030] Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications are possible without departing from the intent and scope of the invention.

[0031] 4 Tongue plate 10 Buckle 11 Base 12 Latch member 15 Ejector 18a, 18b Ejector spring

Claims

1. A buckle comprising: a base having a bottom and a pair of side walls rising from a pair of side edges of the bottom; a latch member having a claw portion that is rotatably supported on the side wall between a non-latch position and a latch position and rotates to the latch position to engage with the tongue when the tongue is inserted into a predetermined position; a slider lock member that prevents the latch member from moving in the latch release direction when the tongue and the latch member are latched; a slider spring compressed between the slider lock member and the latch member; an ejector for releasing the tongue; an ejector spring that biases the ejector in the direction of releasing the tongue; and a release button provided longitudinally movably on the side wall of the base, which presses the slider lock member during a latch release operation and allows the latch member to move in the latch release direction, wherein the ejector spring comprises a first ejector spring and a second ejector spring arranged in parallel in the short-direction center of the base.

2. The buckle according to claim 1, wherein the first ejector spring and the second ejector spring are connected at one end.

3. A seat belt device comprising: a seat belt to be worn by an occupant; a tongue movably supported by the seat belt; and a buckle according to claim 1 or 2 to which the tongue is locked.

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