SEAT CUSHION EXTENSION DEVICE

Abstract

A seat cushion extension device, wherein the extension device has the following features: a base (200) with a first and a second rack (240, 260) which are provided to be facing each other; a cushion part (400) which is provided on an upper section of the base (200) to move forward / backward; a locking gear wheel part (600) combined with a shaft (460) extending from the cushion part (400) to the base (200), and in which a first gear wheel (620) is provided to engage with the first and second racks (240, 260); and a manipulation part (800) which is combined with the cushion part (400) in such a way as to move forward / backward between the cushion part (400) and the first gear wheel (620), and in which a protruding part (828) is provided on a lower surface of the same, wherein when the manipulation part (800) is moved backwards in such a way that the protruding part lowers the first gear wheel (620), the first gear wheel (620) is released from the second rack (260) and the cushion part (400) changes to be movable.

Description

Technical area

[0001] The present invention relates generally to a seat cushion extension device. More specifically, the present invention relates to a seat cushion extension device that efficiently adjusts the length of a seat cushion installed in a vehicle forwards and backwards. Background of the invention

[0002] Unless otherwise stated, the content described in this identification is not to be considered prior art relating to the claims of this application, and it is not acknowledged that the description in this identification is prior art.

[0003] Generally, a seat cushion extension device is fitted inside a vehicle to support the lower body of a user and is manufactured in such a way that a section of a seat cushion extends forward to provide comfort to users who have different physical limitations.

[0004] In recent times, the use of a motor and planetary gear united in a seat cushion has been avoided in order to reduce the power consumption, manufacturing costs and weight of a seat cushion extension device, and techniques are being developed that use springs as the drive for the movement of the seat cushion.

[0005] In this respect, Korean patent KR 10 1 516 224 B1 discloses a seat cushion extension device using a plurality of coil springs and Korean patent KR 10 1 034 310 B1 discloses a seat cushion extension device using a motor.

[0006] The publication EP 3 254 890 A1 describes a seat cushion extension device that is installed in a vehicle seat to allow the adjustment of a longitudinal position of a front end part of a seat cushion.

[0007] Document DE 10 2011 002 127 A1 discloses automobile seats which include a seat or seat unit with adjustable length with respect to the morphology of the user.

[0008] Publication US 7,578,554 B2 relates to a vehicle seat and, in particular, to a system for adjusting the seat to provide additional thigh support.

[0009] However, due to the use of a motor or a plurality of springs, the seat cushion extension devices of the existing inventions are heavy, and a disadvantage is that moving the seat cushion is difficult when an elastic force of one of the plurality of springs deteriorates. Revelation: Technical Problem

[0010] The present invention provides a seat cushion extension device which can move a seat cushion over a single spring and has high assembly efficiency and low weight due to a simple structure.

[0011] In addition, the technical problems to be solved by the present invention are not limited to those mentioned herein, and a further technical problem not mentioned herein may be apparent to those skilled in the art to which the present invention relates on the basis of the following descriptions. Technical solution to the problem

[0012] A seat cushion extension device according to an embodiment of the present disclosure comprises the following features: a base with a first and a second rack which are provided to be facing each other; a cushion part which is provided on an upper section of the base to move forward / backward; a locking gear wheel part which is combined with a shaft extending from the cushion part to the base and in which a first gear wheel is provided to engage with the first and the second rack;and a manipulation part combined with the cushion part in such a way as to move forward / backward between the cushion part and the first gear wheel, and in which a protruding part is provided on a lower surface of the same, wherein when the manipulation part is moved backward such that the protruding part lowers the first gear wheel, the first gear wheel is released from the second rack and the cushion part changes to be displaceable.

[0013] In addition, the locking gear wheel part can further include a torsion spring which generates an elastic rotational force by combining it with the first gear wheel, whereby when the first gear wheel is released from the second rack, the first gear wheel can be moved forward while being rotated clockwise by the elastic rotational force of the torsion spring.

[0014] Furthermore, the first rack can be designed such that the thickness of the first rack is greater than the thickness of the second rack, and an upper surface of each of the first and second racks can be on the same horizontal line, wherein, when the first gear wheel is lowered and released from the second rack, the cushion part can be moved forward, and then, when the cushion part is moved backward, the first gear wheel can be rotated counterclockwise and the torsion spring can be deformed.

[0015] In addition, the locking gear member may further comprise a coil spring provided in such a shape as to surround the shaft between the shaft and the torsion spring, the coil spring elastically resisting the first gear when the first gear is lowered, wherein when the manipulating member is elastically moved forward and the protruding member is disengaged from the first gear, the first gear can be elastically moved upward, engaged with the first and second racks, and fix the cushion member.

[0016] The base may include springs each disposed in respective displacement grooves provided to be recessed downward in a longitudinally forward / backward extending shape on opposite sides of the first and second racks, wherein a front end of each of the springs is adapted to be combined with the cushion member, wherein when the first gear is disengaged from the second rack, the cushion member can be moved forward by the springs. Beneficial effects

[0017] According to one embodiment of the disclosure of the present description, the seat cushion extension device uses the elastic rotational force of the torsion spring as a drive to move the seat cushion, thereby reducing the consumption of electrical power and the weight of the seat cushion extension device in a vehicle.

[0018] In contrast to an existing seat cushion extension device, the seat cushion extension device also features a simple internal structure and a small number of springs required to power the device, thereby increasing manufacturing ease and assembly efficiency.

[0019] Furthermore, unlike the existing seat cushion extension device in which smooth movement of the seat cushion is difficult due to a difference in elastic force of each of a plurality of coil springs installed in opposite sides of the extension device, the seat cushion extension device of the present disclosure allows the seat cushion to be moved forward by the elastic force of a single torsion spring, so that the seat cushion is moved in a stable manner.

[0020] Since the above-described effects of the present invention are naturally to be implemented by the configuration of the described content, regardless of whether the inventor recognizes such effects or not, the above-described effects are merely a few effects according to the described content, and it is not recognized that all the effects apparent to the inventor are actually described herein.

[0021] In addition, the effects of the present invention will be further apparent from the entire specification of the application, and if those skilled in the art in the technical field to which the specification belongs recognize such effects in the present application even if the effects are not described in explicit sentences, it will be recognized that the effects are described in the present application. Description of the drawings Fig. 1 is a perspective view of a seat cushion extension device according to an embodiment of the present disclosure. Fig. 2 and Fig. 3 are exploded perspective views of the seat cushion extension device of Fig. 1. Fig. 4 is a line II' from Fig. 1 recorded sectional view. Fig. 5 shows sectional views showing the drive of the seat cushion extension device of Fig. Show 1. Fig. 6 is a perspective view of a seat cushion extension device according to another embodiment of the present disclosure. Fig. 7 shows along the line II-II' the seat cushion extension device of Fig. 6 recorded cross-sectional views. Fig. 8 is a perspective view of the Fig. 6 illustrated seat cushion extension device. Modes of invention

[0022] The following describes the configuration, operation, and effects of a seat cushion extension device according to exemplary embodiments with reference to the accompanying drawings. For reference, in the drawings below, components are omitted or schematically illustrated for convenience and clarity, and the size of the components does not reflect their actual size. In addition, the same reference numerals refer to the same components throughout the application, and reference numerals for the same components are omitted in the individual drawings.

[0023] As in Fig. As illustrated in Figure 1, the seat cushion extension device comprises a base 200, a cushion part 400, a locking gear wheel part 600 and a manipulation part 800.

[0024] According to the seat cushion extension device, the cushion part 400 is elastically moved forward by a user pulling the manipulation part 800 upward without having to use an electrically driven motor.

[0025] The base 200 comprises a frame 220, a first rack 240 and a second rack 260.

[0026] The base 200 is configured to include the frame 220 formed in the shape of a plate and the first and second racks 240 and 260 provided in the center of the frame 220 such that teeth of the first and second racks face each other.

[0027] Displacement grooves are formed at the upper ends of opposite sides of the frame 220, each of the displacement grooves being recessed downwards by a predetermined distance, and the cushion part 400 is combined with the base 200 in such a way as to be displaceable forwards or backwards over the displacement grooves.

[0028] The first rack 240 is formed on an inner surface of a groove formed in the center of the frame 220, such that it has a thickness greater than the thickness of the second rack 260, and the second rack 260 is formed on an inner surface of the groove such that it faces the first rack 240 with a predetermined distance between them.

[0029] An upper surface of the first rack 240 and the second rack 260 is each located on the same horizontal plane, and a lower surface of the second rack 260 is formed in the groove in such a way as to be spaced a predetermined distance from the frame 220.

[0030] The cushion part 400 is combined with an upper portion of the base 200 to move forward or backward.

[0031] The cushion part 400 comprises a cushion frame 420, block flanges 440 and a shaft 460.

[0032] The cushion frame 420 is formed in the shape of a plate and has displacement rods provided on a lower surface thereof, the displacement rods being combined with the displacement grooves, and a rim having a ring shape being formed on edges except on a back side of the cushion frame, the rim surrounding a predetermined space open at a lower portion thereof.

[0033] While each of the block flanges 440 is spaced apart from each other by a predetermined distance on opposite sides, a first end of the block flange is combined with an inner side of the edge located on a front side of the cushion frame 420, and a second end thereof is formed to protrude downward, and through holes 10 are formed at lower ends of the block flanges by passing through opposite sides of the block flange.

[0034] While the base 200 and the cushion member 400 are combined with each other, the lower end of each of the block flanges 440 is formed to protrude toward a lower surface of the base 200, and each of the through holes 10 is located at a position lower than a position of the lower surface of the base 200.

[0035] While the base 200 and the cushion member 400 are combined with each other, a first end of the shaft 460 is combined with the lower surface of the cushion frame 420, and a second end of the shaft 460 extends vertically toward a space between the first and second racks 240 and 260 of the base 200.

[0036] While the base 200 and the cushion part 400 are combined with each other, the shaft 460 is formed to be adjacent to a back side of the base 200 and the cushion part 400, and is combined with the locking gear part 600 between the first and second racks 240 and 260.

[0037] The locking gear part 600 is provided between the base 200 and the cushion part 400, and by driving the manipulation part 800, the cushion part 400 is moved forward or the movement of the cushion part 400 is stopped.

[0038] The locking gear part 600 includes a first gear 620 and a torsion spring 640.

[0039] The first gear 620 is rotatably combined with the shaft 460 by inserting a second end of the shaft 460 into a hole passing through a center of the first gear 620 and can be moved up and down along the shaft 460.

[0040] A first end of the torsion spring 640 is combined with the lower surface of the cushion frame 420, and a second end of the torsion spring is combined with a lower surface of the first gear 620 while surrounding the shaft 460. Accordingly, the torsion spring is deformed according to clockwise or counterclockwise rotation of the first gear 620 and provides an elastic rotational force.

[0041] When the first gear 620 moves downward by a predetermined distance, the first gear is disengaged from the second rack 260 and changes to a state where it can be rotated by the torsion spring 640.

[0042] When the first gear 620 is rotated clockwise by the elastic force of the torsion spring 640 while in a state of engagement with the first rack 240, the first gear 620 moves along the first rack 240 together with the cushion frame 420.

[0043] The manipulation part 800 is combined with the cushion part 400 to move forward or backward between the cushion part 400 and the first gear 620, and by manipulating the manipulation part, the cushion part 400 is moved forward or the movement of the cushion part 400 is stopped.

[0044] The manipulation part 800 comprises a rod 820, a lever 840 and springs 860.

[0045] The first end of the rod 820 is arranged towards the front and the second end of the rod is formed in such a way as to extend to the rear in the form of a plate and to be divided into two opposing branches, with a through groove of a middle of the two branches arranged between them.

[0046] While the base 200 and the cushion part 400 are combined, the rod 820 moves forward or backward between the first and second racks 240 and 260, and the second end of the rod, which is divided into two branches, is arranged to extend from a position above the first gear wheel 620, with the shaft 460 being between the two branches.

[0047] While a first end of the lever 840 is rotatably combined with a shaft passing through each of the through holes 10 of the block flanges 440, a portion of an upper end of the lever is rotatably combined with a first end of the rod 820, and a second end of the rod extends rearward and downward in the form of a plate.

[0048] Accordingly, when the lever 840 moves upwardly between the block flanges 440 by rotation about the shaft through a predetermined angle, the portion of the upper end of the lever combined with the first end of the rod 820 moves the rod 820 rearwardly by a predetermined distance.

[0049] A first end of each of the springs 860 is combined with the second end of the rod 820, with a predetermined distance between the springs, and a second end of the spring extends rearward and is combined with the rear of the frame 220. Accordingly, the springs provide the elastic force to move the rod 820 forward.

[0050] Specifically, the staff comprises 820 with reference to Fig. 3 a rod frame 822, the shaft 824, a first spring holder 826, a second spring holder 827 and protruding parts 828.

[0051] A section of a first end of the rod frame 822, located in a front face of the same, is formed in the form of a plate, and a second end of the rod frame, located at a rear face of the same, is formed such that it decreases in size by a predetermined distance towards the center of the same on opposite surfaces thereof.

[0052] The shaft 824 is designed to extend in a cylindrical form to the opposite sides of the rod frame 822 at its first end and is inserted into the section of the upper end of the lever 840, so that the lever 840 is rotatably combined with the shaft.

[0053] A first end of the first spring holder 826 is combined with a first side of the second end of the rod frame 822 and a second end of the same extends rearward, and a section of a middle of the second end of the first spring holder is inserted into one of the springs 860.

[0054] A first end of the second spring holder 827 is combined with a second side of the second end of the rod frame 822 such that it is spaced a predetermined distance from the first end of the first spring holder 826, and a second end of the second spring holder extends rearward, and a section of the middle of the second end of the second spring holder is inserted into the remaining springs 860.

[0055] Accordingly, the second end of each of the first and second spring holders 826 and 827 pulls or pushes each of the springs 860, while the same is moved forward or backward by the drive of the lever 840.

[0056] With reference to Fig. 4 Each of the projecting parts 828 extends by decreasing downwards from a lower surface of the first end of the first spring retainer 826 and the second spring retainer 827 respectively, and while the base 200 and the cushion part 400 are combined, a position of a lower surface of each of the projecting parts 828 resembles or lies below a position of the lower surface of the second rack 260.

[0057] Inclined surfaces are formed on a front and a back side of each of the projecting parts 828. When a second end of the lever 840 is moved upwards by manipulation of a user and the rod 820 is moved downwards by a predetermined distance, the inclined surfaces of each of the projecting parts 828 push the first gear wheel 620 downwards, while passing along opposite sides of the shaft 460.

[0058] While a lower surface of each of the protruding parts 828 is in close contact with an upper surface of the first gear 620, one side of the first gear 620 is located below a lower surface of the second rack 260. Accordingly, the first gear 620 deviates from the second rack 260 and changes to the state where it can rotate with the first rack 240.

[0059] While the base 200 and the cushion member 400 are combined with each other, the torsion spring 640 is combined with the first gear 620 at a lower portion thereof while being twisted, and when the first gear 620 changes to the state where the same can rotate, the first gear 620 is rotated clockwise by the elastic rotating force of the torsion spring 640.

[0060] When the first gear wheel 620 rotates clockwise, the first gear wheel 620 moves along the first rack 240, and the cushion part 400 moves forward together with the first gear wheel 620.

[0061] When a user lowers the first gear wheel 620 via the lever 840 and pushes the cushion part 400 backwards by a predetermined distance in the state in which the cushion part 400 is moving forwards, the first gear wheel 620 moves backwards by rotating counterclockwise in the state in which it is engaged with the first rack 240.

[0062] When the first gear 620 rotates counterclockwise, the torsion spring 640 twists, and the elastic torque exerted by the second end of the torsion spring 640 on the first gear 620 increases. The torsion spring creates resistance as the cushion member 400 moves backward, and the position of the cushion member 400 can be precisely adjusted while the cushion member 400 resists the resistance.

[0063] Accordingly, the seat cushion extension device can conveniently control the movement of the cushion part 400 solely through the elastic rotational force of the torsion spring 640, without driving the motor, thereby reducing the power consumption of a vehicle and the weight of the seat cushion extension device.

[0064] With reference to Fig. The lever 840 comprises lever shafts 842, retaining rings 844 and a manipulation plate 846, and the locking gear wheel part 600 further comprises a coil spring 660.

[0065] A first end of each of the lever shafts 842 is combined with each of the opposite sides of the first end of the lever 840, and a second end of each of the lever shafts projects in the form of a cylinder to each of the opposite sides. Accordingly, the lever shaft is rotatably combined with each of the block flanges 440.

[0066] A first end of the manipulation plate 846 is rotatably combined with the lever shaft 842, and a second end of it is bent downwards, after extending by a predetermined distance to the front of the lever shaft 842, and extends in the form of a plate by a predetermined distance.

[0067] Each of the fixing rings 844 is formed in the shape of a ring bent backward from an upper end of the manipulation plate 846, and is rotatably combined with each of opposite sides of the shaft 824 by surrounding each of the opposite sides of the shaft 824.

[0068] When a user moves the second end of the manipulation plate 846 upward by a predetermined distance, the lever 840 is moved relative to the lever shaft 842 and the fixing ring 844 is moved rearward, so that the rod 820 is moved rearward.

[0069] The coil spring 660 is designed to surround the shaft 460 between the shaft 460 and the torsion spring 640, and a first end of the coil spring, which is located on a lower section thereof, is combined with a lower end section of the shaft 460, and a second end of the same is combined with a lower surface of the first gear wheel 620 by extending upwards.

[0070] Each of the inclined surfaces located behind each of the protruding parts 828 gradually lowers the first gear wheel 620 as it comes into close contact with the upper surface of the first gear wheel 620 when the rod 820 moves backward, and when the lower surface of the protruding part 828 is brought into close contact with the upper surface of the first gear wheel 620, the first gear wheel 620 is released from the second rack 260 and changes into the state in which it can rotate.

[0071] While the second end of the manipulation plate 846 is moved upwards, a user can adjust the position of the cushion part 400, and when the user releases the manipulation plate 846 after adjusting the position of the cushion part 400, the manipulation plate 846 is lowered by the elastic force of the springs 860 and the protruding part 828 is moved forwards.

[0072] As the protruding part 828 moves forward, the first gear wheel 620 is moved to an initial position by being moved upward by the coil spring 660, engages with the first and second racks 240 and 260 and fixes a position of the cushion part 400, thus stopping the displacement of the cushion part 400.

[0073] Accordingly, the seat cushion extension device uses the elastic rotational force of the torsion spring 640 as a drive to move the cushion part 400, thereby saving electrical power and reducing the weight of the device.

[0074] Furthermore, the seat cushion extension device eliminates the need for the installation of a motor or springs arranged in an existing base 200, solely through the installation of the springs 860 and the torsion spring 640, thereby reducing the manufacturing costs and the weight of the device.

[0075] In contrast to the conventional seat cushion extension device, the seat cushion extension device also features a simple assembly structure in which the manipulation part 800 is combined with the lower surface of the cushion part 400 and the first gear wheel 620 is combined with the cushion part 400 via the shaft 460, thereby increasing manufacturing convenience and assembly efficiency.

[0076] Fig. Figure 6 is a perspective view of a seat cushion extension device 120 according to a further embodiment of the present disclosure. Fig. 7 shows along the line II-II' the seat cushion extension device of Fig. 6 recorded cross-sectional views. Fig. 8 is a perspective view of the Fig. 6 illustrated seat cushion extension device.

[0077] The seat cushion extension device 120 according to the exemplary embodiment is essentially the same as the seat cushion extension device from Fig. 1 to 5, except that a first and a second spring shaft 270 and 280, and a first and a second spring 275 and 285 of a base 300, a first and a second displacement part 520 and 530, a first and a second insertion part 540 and 550 of a cushion part 500, and a locking gear part 700 are present. Accordingly, the substantially identical components use the same reference numerals and names, and overlapping descriptions of the same components are omitted.

[0078] As in Fig. As illustrated in Figures 6 to 8, the seat cushion extension device 120 comprises the base 300, the cushion part 500 and the locking gear wheel part 700.

[0079] The base 300 also includes the first spring shaft 270, the first spring 275, the second spring shaft 280 and the second spring 285.

[0080] The frame 220 is formed in the form of a plate, and the first and second racks 240 and 260 are each formed on inner surfaces that point towards the groove which is cut downwards in a longitudinally forward and backward extending shape in the middle of the frame 220, the first and second racks 240 and 260 facing each other.

[0081] A first displacement groove 50 is formed between the first rack 240 and a first side of the frame 220, wherein the first displacement groove extends towards a lower section of the frame 220 in such a way that it extends longitudinally forward / backward and communicates with an outer space at the front of the frame 220 by extending forward.

[0082] A second displacement groove 55 is formed between the second rack 260 and a second side of the frame 220, wherein the second displacement groove is excavated in a longitudinally forward / rearward extending shape towards the lower section of the frame 220 and communicates with the outer space at the front of the frame 220 by extending forward.

[0083] While the first spring shaft 270 is inserted into the first displacement groove 50, a first end of the first spring shaft 270 is combined with a rear portion of the frame 220 located in the first displacement groove 50, and a second end of the first spring shaft 270 extends forward by a predetermined distance.

[0084] While the first spring 275 is inserted into the first displacement groove 50, one end of the first spring 275 surrounds the first spring shaft 270, and a second end of the same extends forward. Accordingly, a section of the first spring is inserted into the cushion part 500 and combined with the cushion part 500.

[0085] While the second spring shaft 280 is inserted into the second displacement groove 55, a first end of the second spring shaft is combined with a rear section of the frame 220 located in the second displacement groove 55, and a second end of the same extends forward by a predetermined distance.

[0086] While the second spring 285 is inserted into the second displacement groove 55, one end of the second spring surrounds the second spring shaft 280, and a second end extends forward. Accordingly, a section of the second spring is inserted into the cushion part 500 and combined with the cushion part 500.

[0087] When the lever 840 is pulled forward and upward, the rod 820 is moved accordingly backward, the protruding part 828 moves the first gear wheel 620 downward, the first gear wheel 620 is released from the second rack 260, and the cushion part 500 is moved forward by the elastic force of the first and second springs 275 and 285.

[0088] The cushion part 500 further includes the first displacement part 520, the second displacement part 530, the first insertion part 540 and the second insertion part 550.

[0089] A guide groove 60 is formed in the lower surface of the cushion frame 420 by excavating it in a rectangular shape from the center of the lower surface of the cushion frame 420 upwards and extending backwards and opening to communicate with the outside.

[0090] The first displacement part 520, the second displacement part 530, the first insertion part 540 and the second insertion part 550, which are located in the guide groove 60, are each designed to protrude downwards from the lower surface of the cushion frame 420.

[0091] A section of the upper end of the frame 220 is combined with the cushion part 500 in such a way that the frame 220 moves forward or backward while the section of the upper end of the frame 220 is inserted in the guide groove 60.

[0092] A first end of the first displacement part 520, which is provided in a shape of a rod formed longitudinally forward / backward, is combined with the lower surface of the cushion part 500 at a position corresponding to a direct upper portion of the first displacement groove 50, and a second end of the first displacement part 520 extends downward, and portions of opposite surfaces of the second end thereof protrude to opposite sides to form protruding parts.

[0093] A first space is formed at a rear section of the second end of the first displacement part 520 by exposing it upwards by a predetermined distance from a lower surface of the first displacement part 520, such that a section of the second end of the first spring 275 is inserted into the first space, and a first projection is provided at a front of the first space by extending it rearwards from the first displacement part 520 and is inserted into the second end of the first spring 275.

[0094] A first end of the second displacement part 530, which is provided in a shape of a rod formed longitudinally forward / backward, is combined with the lower surface of the cushion part 500 at a position corresponding to a direct upper portion of the second displacement groove 55, and a second end of the second displacement part 530 extends downward, and portions of opposite surfaces of the second end thereof protrude to opposite sides to form protruding parts.

[0095] A second space is provided at a rear portion of the second end of the second displacement part 530 by recessing it upward by a predetermined distance from a lower surface of the second displacement part 530 such that a portion of a second end of the second spring 285 is inserted into the second space, and a second projection is provided at a front side of the second space by projecting rearward from the second displacement part 530 and is inserted into the second end of the second spring 285.

[0096] While one section of an upper end of the frame 220 is inserted into the guide groove 60, each of the first and second displacement parts 520 and 530 is inserted into the first and second displacement grooves 50 and 55 and thus combined to be displaceable forwards and backwards.

[0097] With reference to Fig. 3 and Fig.8 The first insertion part 540 protrudes from the lower surface of the cushion frame 420 in a longitudinally forward / backward extending form of a rod at a downward position corresponding to a direct upper section of the second spring holder 827, and a section of the second spring holder 827 and the spring 860 are inserted into the interior of the first insertion part 540 at a front face of the same.

[0098] The second spring holder 827 is inserted into the first insertion part 540 in such a way as to be displaceable forwards and backwards, and while a rear section of the spring 860 is inserted into the first insertion part 540 by a predetermined distance, the movement of the spring is stopped by a rear surface of the first insertion part 540.

[0099] The second insertion part 550 extends in a longitudinally forward / backward extending form of a rod from the lower surface of the cushion frame 420 at a position corresponding to a direct upper section of the first spring holder 826, and a section of the first spring holder 826 and the spring 860 are inserted into the interior of the second insertion part 550 at a front face of the same.

[0100] The first spring holder 826 is inserted into the second insertion part 550 so as to be slidable forward and backward, and while a rear portion of the spring 860 is inserted into the second insertion part 550 by a predetermined distance, the movement of the spring is stopped by a rear surface of the second insertion part 550.

[0101] When the rod 820 is moved backwards by the drive of the lever 840, the springs 860 contract accordingly, and the forward movement of the cushion part 500 is restricted, and when the drive of the lever 840 is stopped, the lever 840 is moved to an initial position by the elastic force of the springs 860.

[0102] In addition, the elastic force that increases as the springs 860 are compressed by the drive of the lever 840 restricts the drive of the lever 840. Accordingly, it prevents the rod 820 from being moved forwards or backwards by any movement or deceleration of the vehicle, and the lever 840 is manipulated precisely.

[0103] Although exemplary embodiments of the present invention have been described with reference to the accompanying drawings, these exemplary embodiments and configurations of the drawings have been disclosed for illustrative purposes only and do not represent the entire technical nature of the present invention. Accordingly, it is apparent to those skilled in the art that numerous modifications, additions, and substitutions are possible without altering the scope of protection, nature, or invention. Therefore, the embodiments described above are to be regarded in all respects as illustrative and not limiting, and the scope of protection of the present invention is specified by the scope of protection in the following claims instead of a detailed description.Any changes or modifications derived from the meaning and scope of protection of the patent claims and their equivalent concepts shall be considered as being included in the scope of protection of the present invention. Industrial applicability

[0104] The seat cushion extension device allows the length of the seat cushion installed in a vehicle to be adjusted forwards / backwards and can be used in private or commercial vehicles. Reference symbol 10 through holes 50, 55 shift grooves 60 guide groove 120 Seat cushion extension device 200 base 220 frames 240 first rack 260 second rack 270 first spring shaft 275 first spring 280 second spring shaft 285 second spring 300 base 400 pillow part 420 cushion frames 440 block flanges 460 wave 500 pillow pieces 520 first displacement part 530 second shift part 540 first introductory part 550 second introductory part 600 locking gear part 620 first gear wheel 640 torsion spring 660 coil spring 700 locking gear part 800 Manipulation part 820 staff 822 rod frame 824 wave 826 first spring holder 827 second spring holder 828 protruding part 840 levers 842 lever shafts 844 mounting rings 846 Manipulation plate 860 springs

Claims

[1] A seat cushion extension device, the extension device having the following features: a base (200) having first and second racks (240, 260) provided to face each other; a cushion member (400) provided on an upper portion of the base (200) to move forward / backward; a locking gear member (600) combined with a shaft (460) extending from the cushion member (400) to the base (200), and having a first gear (620) provided to engage the first and second racks (240, 260); and a manipulation part (800) combined with the cushion part (400) to move forward / backward between the cushion part (400) and the first gear (620), and having a protruding part (828) provided on a lower surface thereof, wherein when the manipulation part (800) is moved rearward such that the protruding part lowers the first gear (620), the first gear (620) is disengaged from the second rack (260) and the cushion part (400) changes to be displaceable. [2] The seat cushion extension device according to claim 1, wherein the locking gear member (600) further comprises a torsion spring (640) that generates an elastic rotational force by combining the same with the first gear (620), wherein when the first gear (620) is disengaged from the second rack (260), the first gear is moved forward while being rotated clockwise by the elastic rotational force of the torsion spring (640). [3] The seat cushion extension device according to claim 2, wherein the first rack (240) is formed such that a thickness of the first rack (240) is greater than a thickness of the second rack (260), and an upper surface of each of the first and second racks (260) is located on the same horizontal line, wherein when the first gear (620) is lowered and disengaged from the second rack (260), the cushion member (400) is moved forward, and when the cushion member (400) is moved rearward, the first gear (620) is rotated counterclockwise and the torsion spring (640) is deformed. [4] The seat cushion extension device according to claim 3, wherein the locking gear part (600) further comprises a coil spring (660) provided in such a shape as to surround the shaft (460) between the shaft (460) and the torsion spring (640), the coil spring (660) elastically resisting the first gear (620) when the first gear (620) is lowered, and when the manipulating part (800) is elastically moved forward and the protruding part is disengaged from the first gear (620), the first gear (620) is elastically moved upward, engaged with the first and second racks (260), and fixes the cushion part (400). [5] The seat cushion extension device according to claim 1, wherein the base (200) has springs (860) each disposed in respective displacement grooves (50, 55) provided to be recessed downward in a longitudinally forward / rearward extending shape on opposite sides of the first and second racks (260), wherein a front end of each of the springs (860) is adapted to be combined with the cushion member (400), wherein when the first gear (620) is disengaged from the second rack (260), the cushion member (400) is moved forward by the springs (860).

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