JP7614494B2 - Cushion length adjustment device for vehicle seats - Google Patents

Description

The present invention relates to a cushion length adjustment device for adjusting the length of a cushion provided on a vehicle seat such as an automobile seat.

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Application Laid-Open No. 2003-233999, there has been known a cushion length adjustment device that utilizes a link mechanism to adjust the length of a cushion of an automobile seat.
The cushion length adjustment device described in Patent Document 1 extends the front part of the cushion forward, and the extension part that is integral with the front part can be pushed forward by a drive mechanism to lengthen the cushion length, and pulled backward to shorten the cushion length.

Japanese Utility Model Application Publication No. 07-13244

In the cushion length adjustment device described in Patent Document 1, when the front of the cushion is pulled backwards using a link mechanism to shorten the cushion length, the cover is rolled up, and when the front of the cushion is extended forward, the cover is sent out, thereby preventing the cover from becoming over-tight or slack.
However, as described above, the cushion length adjustment device described in Patent Document 1, which adjusts the cushion length using a link mechanism and prevents the cover from becoming over-tight or loose, has the problem that its structure is complex and the device is large.

The present invention was made in consideration of the above problems, and aims to provide a compact vehicle seat cushion length adjustment device with a simple structure that can adjust the length of the vehicle seat cushion and prevent the cover from becoming overtight or loose.

In order to solve the above problem, the invention described in claim 1 is:
A cushion length adjustment device for a vehicle seat, which adjusts the cushion length by moving a movable frame in the forward and backward directions, the movable frame being movably mounted on a fixed frame and supporting a front lower surface of a cushion,
The cushion includes a resilient pad and a skin that covers a surface of the pad and has an extension that extends longer than a tip end of the pad;
The movable frame includes:
A pair of brackets each extending downward from each side;
A pair of arms rotatably attached to the pair of brackets, respectively;
a rod-shaped member connecting the tip ends of the pair of arms,
The fixed frame is provided with a hook portion positioned in front of the rod-shaped member, and the tension of the skin causes the tip of the pad to roll downward, and the extension portion contacts the outer periphery of the rod-shaped member from below and then folds back forward at the top, so that the end is hooked onto the hook portion.

The invention described in claim 2 is characterized in that in the vehicle seat cushion length adjustment device described in claim 1, the biasing means is a tension spring, and the tension spring is tensioned so that its axis is located above the rotation center of the arm in the first state and its axis is located below the rotation center of the arm in the second state.

The invention described in claim 3 is characterized in that in the vehicle seat cushion length adjustment device described in claim 2, the biasing means is a tension spring, and the tension spring is tensioned so that its axis is located above the rotation center of the arm in the first state and its axis is located below the rotation center of the arm in the second state.

The invention described in claim 4 is the vehicle seat cushion length adjustment device described in claim 2 or 3, characterized in that the bracket is provided with a stopper piece that limits the rotation angle range of the arm.

The invention described in claim 5 is characterized in that in the vehicle seat cushion length adjustment device described in any one of claims 1 to 4, a collar is provided on the outer periphery of the rod-shaped member.

The invention described in claim 6 is characterized in that in the vehicle seat cushion length adjustment device described in any one of claims 1 to 5, the fixed frame is provided with a pair of guide rails that guide the movable frame in the front-rear direction, and the hook portion is formed of a pipe fixed between the front ends of the pair of guide rails.

According to the invention described in claim 1, when the pad of the seat cushion placed on the movable frame is moved backward or forward together with the movable frame, a rod-shaped member that is provided between a pair of arms and has the seat cushion skin contacting the outer periphery from below while being folded forward at the top moves forward or backward relative to the hook to which the end of the skin is hooked. This allows the tip of the pad to be rolled downward by the tension of the skin, contracting or expanding it, and the length of the cushion can be adjusted with a simple structure without compromising the seating comfort.

According to the invention described in claim 2, a biasing means is provided to bias the arm in the folding direction of the extension of the skin, so that the arm can be prevented from rotating in the opposite direction to the folding direction due to the tension of the skin, and excessive tension or slackness of the skin can be prevented.

According to the invention described in claim 3, the arm can be held in the first state or the second state by the elastic restoring force of the tension spring, so that in the second state, the space below the movable frame can be opened, and the skin assembly work can be easily performed by hooking the hook at the end of the skin onto the hook portion. Also, in the first state during normal use, the arm can be rotated upward and stored in the space below the movable frame, eliminating the need to secure a large space to arrange the arm, thereby enabling space saving.

According to the invention described in claim 4, a stopper piece is provided to restrict the rotation angle of the arm, so that the elastic restoring force of the tension spring can be used to prevent the tip of the arm or the rod-shaped member from being pressed against the fixed frame and coming into contact with it.

According to the invention described in claim 5, a collar is provided on the outer periphery of the rod-shaped member, which reduces the frictional force when the cover moves, and allows the tip of the seat cushion to contract and expand smoothly.

According to the invention described in claim 6, the hook portion is formed of a bent pipe fixed between the front ends of a pair of guide rails, so that the end of the skin can be easily hooked to the hook portion by providing a hook on the end of the skin and hooking the hook on the bent pipe serving as the hook portion.

FIG. 2 is a perspective view showing a seat frame that constitutes a framework of the vehicle seat. 3A and 3B are a perspective view and a front view showing a fixed frame and a movable frame that configure the cushion frame. FIG. 13 is an enlarged side view of a main portion of a specific example of a winding structure for a seat cushion cover, showing the front part of the cushion in an extended state. 1 is an enlarged side view of a main portion showing a contracted state of a front part of the cushion due to the wrap-around structure of the cover of the embodiment. FIG. 1 is an enlarged side view of a main portion showing a state in which a skin end portion is assembled in the skin winding structure of the embodiment. FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a cushion length adjustment device for an automobile seat will be described below with reference to the drawings.
In the following description, unless otherwise specified, the traveling direction of the vehicle is referred to as the forward direction, the opposite direction is referred to as the rearward direction, the left side of the occupant seated in the vehicle seat is referred to as the left direction, and the right side is referred to as the right direction. In this embodiment, the front-rear direction, left-right direction (width direction), and up-down direction of the vehicle seat are the same as the front-rear direction, left-right direction (width direction), and up-down direction of the vehicle.

The vehicle seat in this embodiment includes at least a seat cushion that supports the thighs and buttocks of a person, and a seat back whose lower end is supported by the seat cushion and serves as a backrest. In addition, a headrest that supports the person's head, armrests that support the person's arms, etc. are provided as necessary.

In FIG. 1, reference numeral 10 denotes a cushion frame that forms the framework of the seat cushion. The cushion frame 10 is mainly composed of a pair of left and right cushion side frames 11A, 11B, a back pipe frame 12 that connects the rear ends of the cushion side frames 11A, 11B, a pan frame 13 that spans between the cushion side frames 11A, 11B and the back pipe frame 12 and connects them as a pressure-receiving member, and a back frame 14 that stands upright from the rear ends of the cushion side frames 11A, 11B. Of these, the pan frame 13 is a pressure-receiving member made of a metal plate material that receives the weight of the occupant, is formed in a roughly box shape, and is capable of housing a cushion pad.

A movable frame 15 for allowing the front of the cushion to move back and forth is provided on the front of the cushion frame 10. Although not shown in Fig. 1, a seat cushion is provided on the cushion frame 10, the seat cushion being made of a cushion pad made of an elastic material and a skin that covers the surfaces of the cushion frame 10 and the cushion pad.
Similarly, the seat back is mainly composed of a back frame 14, a cushion pad provided on the front surface of the back frame 14, and a skin that covers the back frame 14 and the cushion pad and also covers the surface of the seat back.

The side frames 14A of the back frame 14 are provided with side airbags 16 that inflate when an impact equal to or greater than that experienced when a car collides sideways at a speed equal to or greater than a certain level.
A pair of left and right slide rails 17A, 17B are provided below the cushion frame 10 to enable the cushion frame 10, i.e., the entire seat, to slide to any desired front-rear position relative to the vehicle floor based on the operation of the occupant. Sliders (not shown) that fit into the slide rails 17A, 17B are provided on the lower surfaces of the cushion side frames 11A, 11B.

2 shows the movable frame 15 and the fixed frame 18 that supports it. Of these, (A) is a perspective view, and (B) shows the fixed frame 18 as viewed from the front side with the movable frame 15 removed.
2A, the movable frame 15 is in the form of a substantially flat plate with a front end 15a curved downward, and a cushion pad is placed on this movable frame 15. A skin take-up mechanism 50 attached to a flat bracket 51 that hangs down is provided on one side of the movable frame 15, and an L-shaped link arm 53 is rotatably attached to this bracket 51 by a pin shaft 52, as will be described in detail later. Although not shown, a bracket 51, pin shaft 52, and link arm 53 similar to those described above are provided on the opposite side of the movable frame 15.

As shown in FIG. 2(B), the fixed frame 18 has a flat plate-like central portion and is bent so that both left and right sides are one step higher than the central portion. A pair of guide rails 20A, 20B are supported by support blocks 19A, 19B on both left and right sides of the top surface of the central flat portion and have grooves on the top surface that run along the front-to-rear direction. Furthermore, a pair of sliders 21A, 21B provided on the underside of the movable frame 15 are engaged with the grooves of the guide rails 20A, 20B, and the sliders 21A, 21B move along the grooves of the guide rails 20A, 20B, causing the movable frame 15 above them to move in the front-to-rear direction.

Here, the guide rails 20A, 20B and the sliders 21A, 21B are engaged in a tight state with relatively little gap, and the movable frame 15 is configured not to move easily due to friction unless a relatively large force is applied to the movable frame 15 in the forward and backward directions. Note that the movable frame 15 may be configured to move easily with a small force, and a locking mechanism may be provided to prevent the movable frame 15 from moving relative to the fixed frame 18.
2B, a hook 22 made of a bent pipe is attached to the front ends of the guide rails 20A and 20B so as to straddle the guide rails 20A and 20B from below. The reference numeral 23 denotes a movable mechanism.

Figures 3 to 5 show a specific example of the seat cushion skin winding mechanism, which is a key part of the present invention, and show the structure of the front end of the movable frame 15 and fixed frame 18, together with the cushion pad and skin, viewed enlarged from the side. Of these, Figure 3 shows the state when the skin is stored (when the front of the seat is retracted), Figure 4 shows the state when the skin is deployed (when the front of the seat is extended), and Figure 5 shows the assembled state. In Figures 3 to 5, reference numeral 24 denotes the cushion pad, and reference numeral 25 denotes the skin.

As shown in FIG. 3, the skin 25 is joined to the surface of the cushion pad 24 so as to cover the upper and front surfaces of the cushion pad 24, and has an extension that extends longer than the tip of the cushion pad 24. The cushion pad 24 is made of an elastic material such as urethane foam, and its front end is curved along the front end 15a of the movable frame 15. More specifically, the cushion pad 24 is deformed so that the tip is curved downward due to the tension generated when the tip of the skin 25 is pulled backward (to the right in the figure), and when the tension of the skin 25 is released, the tip can be deformed so that it moves forward (to the left in the figure) due to elastic restoring force.

As shown in Fig. 3, the skin winding mechanism 50 has an end of a folding wire (or rod) 54 fixed to the tip of a link arm 53 that is rotatably supported by a pin shaft 52 on the bracket 51 fixed to the side of the movable frame 15. A tension spring 56 is also tensioned between a locking pin 55A planted in the middle of the link arm 53 and a locking pin 55B planted in the upper part of the bracket 51.

The tension spring 56 is tensioned so that its central axis, i.e., the line connecting the centers of the locking pins 55A and 55B, is located rearward (to the right in the figure) of the center of the pin shaft 52 when the link arm 53 is in a horizontal position, as shown in Figure 3. As a result, the elastic restoring force of the tension spring 56 acts to urge the tip of the link arm 53 upward toward the movable frame 15. In addition, the bracket 51 is provided with a stopper piece 57A that prevents the link arm 53 from rotating more than a predetermined angle by abutting against it. The stopper piece 57A may also be provided on the link arm 53 side.

The folding wire 54 has a length approximately equal to the width of the movable frame 15, and the other end is fixed to the tip of a link arm 53 provided on the opposite side of the movable frame 15. The extension of the skin 25 is then wound half a turn from bottom to top around the folding wire 54, folding it back so that the tip faces forward, and a hook 58, the base of which is attached to the tip of the skin 25, is hooked onto a hook portion 22 provided on the tip of the fixed frame 18 while tension is applied to the skin 25.

In addition, a long, thin resin collar 59 is attached to the outer periphery of the return wire 54, and the cover 25 is wrapped around the outer periphery of the collar 59. The rotation of the collar 59 reduces frictional resistance, allowing the cover 25 to move smoothly along the outer periphery of the return wire 54.
The hooks 58 may have a J-shaped cross section and may be continuous in the width direction of the sheet, or may be made of wire and provided in multiples at predetermined intervals along the edge of the skin 25. Furthermore, in order to make it difficult for the hooks 58 to come off the hooking portions 22, the hooks 58 may be formed in an R-shape with a slight opening in a side view.

FIG. 4 shows the state when the cover is deployed (when the front part of the seat is extended).
3, the hook 22 on the fixed frame 18 side to which the hook 58 is hooked moves backward (rightward in the figure) relative to the movable frame 15. Then, as shown in FIG. 4, the hook 22 approaches the folding wire 54 at the tip of the link arm 53, so that the skin 25 moves clockwise around the outer periphery of the collar 59 and is sent out from the space below the movable frame 15.

As a result, the tension of the skin 25 is relaxed, and the elastic restoring force of the seat cushion pad 24 causes the tip of the pad to move obliquely upward and forward, causing the seat cushion to extend forward. In this way, the seat cushion extends forward due to the deformation of the tip of the cushion pad 24, making it possible to adjust the cushion length while preventing a decrease in seating comfort.
When the skin 25 moves clockwise around the outer periphery of the collar 59 and is sent out, a clockwise force acts on the link arm 53, but this force is absorbed by the elastic restoring force of the tension spring 56, preventing the link arm 53 from rotating in the clockwise direction and preventing the skin from becoming overly tight or loose.

4, the hook 22 on the fixed frame 18 side to which the hook 58 is hooked moves forward (leftward in the figure) relative to the movable frame 15. Then, as shown in FIG. 3, the hook 22 moves away from the folding wire 54 at the tip of the link arm 53, so that the cover 25 moves counterclockwise around the outer periphery of the collar 59 and is drawn into the space below the movable frame 15.
As a result, the tension acting on the skin 25 becomes stronger, so that the elastic restoring force of the pad 24 of the seat cushion causes the tip of the pad to move diagonally downward and rearward, causing the seat cushion to retract rearward.

FIG. 5 shows the state in which the end portion of the skin 25 is being assembled.
When assembling the end of the skin 25, as shown in Fig. 5, the link arm 53 is rotated clockwise while the movable frame 15 is moved backward (to the right in the figure). At this time, the central axis of the tension spring 56, i.e., the line connecting the centers of the locking pins 55A and 55B, is positioned further from the center of the pin shaft 53 (to the left in the figure). As a result, the elastic restoring force of the tension spring 56 acts to urge the tip of the link arm 53 forward.

Due to the above-described action, sufficient clearance is secured between the collar 59 at the tip of the link arm 53 and the hook portion 22, so that the skin assembly work can be easily performed by hooking the hook 58 at the end of the skin 25 onto the hook portion 22 exposed in the space below the movable frame 15.
5, after the hook 58 is hooked on the hooking portion 22, the link arm 53 is rotated counterclockwise to transition to the state shown in FIG. 4. As a result, by storing the link arm 53 upward during normal use, it is not necessary to secure space for the link arm 53, and space can be saved. Note that the reference numeral 57B denotes a stopper piece for restricting the rotation angle range of the link arm 53 in the clockwise direction.

As described above, the cushion length adjustment device of this embodiment can achieve the function of adjusting the cushion length with a simple configuration of the bracket 51, link arm 53, and tension spring 56, and can prevent the device from becoming large. Another advantage is that sufficient working space can be secured by rotating the link arm 53 downward when assembling the tip of the skin.

Although the present invention has been described above based on the embodiment, the present invention is not limited to the above embodiment and can be modified in various ways without departing from the gist of the present invention. For example, in the above embodiment, the tension spring 56 is provided as a biasing means for biasing the link arm 53 toward the storage position, but a torsion spring can be used instead of the tension spring. Moreover, the tension spring 56 may be provided on only one of the pair of brackets 51 provided on both sides of the movable frame 15.
In addition, in the above embodiment, it has been described that the hook 58 is attached to the end of the skin 25, but it is also possible to provide grommets or rivets at the end of the skin 25 so that the base side of the wire-shaped hook (58) can also be structured to hook the hook.

Furthermore, in the above embodiment, a collar 59 is provided on the return wire 54, but instead of providing a collar, the return wire 54 itself may be supported so as to be rotatable, or the surface of the return wire 54 may be subjected to a low-friction treatment such as a coating.
In addition, in the above embodiment, the present invention is described as being applied to a seat installed in an automobile, which is a passenger car, but the present invention is not limited to this and can be widely applied to seats installed in other automobiles, such as buses and trucks, and vehicle seats installed in vehicles other than automobiles, such as trains, ships, and aircraft.

REFERENCE SIGNS LIST 10 cushion frame 11A, 11B cushion side frame 12 back pipe frame 13 pan frame 14 back frame 15 movable frame 16 side airbag 17A, 17B slide rail 18 fixed frame 19A, 19B support block 20A, 20B guide rail
21A, 21B Slider 22 Hook portion 23 Movable mechanism 24 Cushion pad 25 Cover 50 Cover winding mechanism 51 Bracket 52 Pin shaft 53 Link arm 54 Folding wire (rod-shaped member)
55A, 55B: locking pin 56: tension spring (urging means)
57A, 57B Stopper piece 58 Hook 59 Collar

Claims (6)

A cushion length adjustment device for a vehicle seat, which adjusts the cushion length by moving a movable frame in the forward and backward directions, the movable frame being movably mounted on a fixed frame and supporting a front lower surface of a cushion,
The cushion includes a resilient pad and a skin that covers a surface of the pad and has an extension that extends longer than a tip end of the pad;
The movable frame includes:
A pair of brackets each extending downward from each side;
A pair of arms rotatably attached to the pair of brackets, respectively;
a rod-shaped member connecting the tip ends of the pair of arms,
The fixed frame is provided with a hook portion positioned in front of the rod-shaped member, and the tension of the cover causes the tip of the pad to roll downward, and the extension portion contacts the outer periphery of the rod-shaped member from below while folding back upward and forward, so that the end is hooked onto the hook portion. The vehicle seat cushion length adjustment device according to claim 1, characterized in that at least one of the pair of brackets is provided with a biasing means for biasing the arm in the folding direction of the extension of the skin. The vehicle seat cushion length adjustment device according to claim 2, characterized in that the biasing means is a tension spring, and the tension spring is tensioned so that its axis is located above the rotation center of the arm in the first state of the arm, and its axis is located below the rotation center of the arm in the second state of the arm. The vehicle seat cushion length adjustment device according to claim 2 or 3, characterized in that the bracket is provided with a stopper piece that limits the rotation angle range of the arm. The vehicle seat cushion length adjustment device according to any one of claims 1 to 4, characterized in that a collar is provided on the outer periphery of the rod-shaped member. The vehicle seat cushion length adjustment device according to any one of claims 1 to 5, characterized in that the fixed frame is provided with a pair of guide rails that guide the movable frame in the front-rear direction, and the hook portion is formed of a bent pipe fixed between the front ends of the pair of guide rails.

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