ANTI-JUMP DEVICE, SEAT FOOTREST DEVICE AND CHILD SAFETY SEAT WITH THESE

Abstract

Anti-spring device (100) with: a pair of fixed base parts (130) arranged symmetrically on both sides, wherein the pair of fixed base parts (130) has sliding rails (133) extending along a longitudinal direction and two side walls (131) opposite each other along a transverse direction perpendicular to the longitudinal direction; an extendable part (110) which is movably inserted into the fixed base parts (130) and is able to slide along the guide rails (133) in order to move between an extended position and a retracted position with respect to the fixed base parts (130); a locking part (120) configured to engage with the fixed base parts (130) and the extension part (110) to fix a position of the extension part (110) relative to the fixed base parts (130), the locking part (120) having a handle (121) and two arms (122), the two arms (122) extending from the handle (121) to the two side walls (131) of the fixed base parts (130); and a cross brace (140) which is arranged between the two side walls (131) to prevent the two side walls (131) from being laterally displaced from each other.

Description

Field of expertise

[0001] The present disclosure relates to an anti-jump device, a seat footrest device, and a child safety seat having the anti-jump device. background

[0002] A child safety seat is typically used in a vehicle to ensure a child's safety in the event of a rear-end collision. In some cases, a lower part of the child seat has a foot pedal for the child to place their feet on. The foot pedal can be retractable, meaning it can be pulled out or retracted into the lower part of the seat.

[0003] This extendable foot pedal requires a locking device for locking the foot pedal in the extended or retracted position. It has been discovered that in some cases, the foot pedal may be released from the constraints of the locking device upon impact, causing it to inadvertently spring back (i.e., bounce) from the extended position. Therefore, the object is to provide an anti-jump device that can prevent the aforementioned jumping. This object is achieved by an anti-jump device according to patent claim 1.

[0004] Child safety seats with anti-jump device and seat footrest device are known, for example, from US 2016 / 0 200 225 A1 and CN 106 080 304 A. Summary

[0005] According to the disclosure, an anti-jump device is provided. The anti-jump device comprises: a pair of fixed bases arranged symmetrically on two sides, the pair of fixed bases having slide rails extending along a longitudinal direction and two side walls opposing each other along a transverse direction perpendicular to the longitudinal direction; an extension member movably inserted into the fixed bases and slidable along the slide rail to move between an extended position and a retracted position with respect to the fixed bases;a locking member for connecting the fixed base members and the extension member to fix a position of the extension member relative to the fixed base members, the locking member having a handle and two arms, the two arms extending from the handle to the two side walls of the fixed base members; and a cross brace disposed on the two side walls to prevent the two side walls from being laterally displaced from each other.

[0006] In one embodiment, both ends of the cross brace are inserted into the outer sides of the two side walls and are fixed to the outer sides of the two side walls by fixed stop elements in order to prevent the two side walls from moving laterally away from each other.

[0007] In one embodiment, the cross brace is arranged at a position where one side of the extension part does not impair a movement path of the extension part.

[0008] In one embodiment, the anti-jump device further comprises a cover attached to the extension part and arranged between the cross member and the extension part. The fixed base parts are provided with at least two groups of insertion slots, each provided on opposite surfaces of the two side walls. Both sides of the cover are each provided with plug through slots that match the insertion slots. When the insertion slots are aligned with the plug through slots, the locking part is inserted into the insertion slots and the plug through slots, thus fixing a position of the extension part with respect to the fixed base parts.

[0009] In one embodiment, the locking part is arranged on a side of the extension part facing the cross member, and it comprises a handle and two symmetrically arranged arms, each of which extends from the handle to the two side walls of the fixed base parts, and the ends of each of which are provided with a plug. When the insertion slots are aligned with the plug through slots, the plugs can be inserted into the insertion slots and the plug through slots.

[0010] In one embodiment, the handle is arranged at a lateral center position of the extension part, and the two arms are arcuate components that are bent to extend approximately in a quarter-circle arc from the lateral center position of the handle to the two side walls.

[0011] In one embodiment, the arms are rigid arms. Each of the insertion slots comprises a longitudinal portion and a vertical portion, wherein the longitudinal portion and the vertical portion are each substantially linear and intersect each other at an intersection point, and each of the plugs has a shape corresponding to the insertion slots so that they can be smoothly inserted and fitted into the insertion slots.

[0012] In one embodiment, one group of the at least two groups of insertion slots corresponds to an extended position of the extension part, and another group of the at least two groups of insertion slots corresponds to a retracted position of the extension part.

[0013] In one embodiment, two sliding guides are formed in the casing, the two sliding guides extending to the two side walls with approximately a quarter-circle arc to accommodate the two arms, thereby defining movement paths of the two arms.

[0014] In one embodiment, in the extended or retracted position of the extension part, the arms of the locking part protrude from the sliding guides and are inserted into the insertion slots and the plug through slots, and by pulling with an external force, the arms of the locking part can be retracted into the sliding guides to be disengaged from the insertion slots and the plug through slots, so that the extension part can slide along a longitudinal direction with respect to the fixed base parts.

[0015] In one embodiment, a spring member is arranged between the locking member and the cover, and the spring member applies a restoring force to the locking member so that the two arms of the locking member remain in a state in which they protrude from the sliding guides.

[0016] In one embodiment, the cross brace is disposed approximately in a first third of a longitudinal length of the side walls; a diameter of the cross brace is approximately one-tenth of a length of vertical edges of the side walls; and a length of a portion of the cross brace located between the two side walls is greater than a length of a portion of the cross brace inserted into each of the side walls.

[0017] According to the present disclosure, a seat footrest device is provided. The seat footrest device includes: a foot pedal; and the anti-jump device according to the disclosure, wherein the foot pedal encloses the extension part.

[0018] In one embodiment, the handle of the locking part of the anti-jump device is exposed on a side of the foot pedal facing the crossbar.

[0019] According to the disclosure, a child safety seat is provided. The child safety seat comprises: a seat portion; and the seat footrest device according to the disclosure, wherein the foot pedal of the seat footrest device and the anti-jump device are each disposed below the seat portion. The fixed base portions of the anti-jump device are fixed to a bottom side of the seat portion, wherein the longitudinal direction is a front-to-rear direction of the seat portion and the transverse direction is a left-to-right direction of the seat portion. When the extension portion is in the extended position, the foot pedal protrudes from a bottom side of the seat portion toward a front side of the seat portion. When the extension portion is in the retracted position, the foot pedal is at least partially located below the bottom side of the seat portion. The handle of the locking portion of the anti-jump device is exposed below the foot pedal. Short description of the drawings

[0020] Embodiments of the present disclosure are described in more detail below in conjunction with the accompanying drawings, in which: Fig. 1 is a perspective view of a child safety seat according to the disclosure. Fig. 2 is a perspective view of the child safety seat according to the disclosure from a different angle. Fig. 3A is a perspective view of the child safety seat according to the disclosure from a different angle, also showing an anti-jump device; and Fig. Figure 3B is an enlarged partial view of Fig. 3A. Fig. 4A shows the child safety seat according to the disclosure, with a panel of the anti-jump device removed to more clearly show its internal structure; and Fig. 4B is an enlarged partial view of Fig. 4A. Fig. 5A shows the child safety seat according to the disclosure, with the panel and a pull-out part of the anti-jump device removed to more clearly show its internal structure; and Fig. Figure 5B is an enlarged partial view of Fig. 5A. Fig. 6 shows the child safety seat according to the disclosure, showing a sliding guide in the cover of the anti-jump device. Fig. 7 shows a pull-out part of the child safety seat according to the disclosure. Fig. 8 shows a locking part of the child safety seat according to the disclosure. Fig. 9A shows a bottom perspective view of the child safety seat according to the disclosure, with a fixed base portion removed to show a positional relationship between the extension portion, the trim panel, and a connector; and Fig. 9B is an enlarged partial view of Fig. 9A. Fig. 10A shows a bottom perspective view of the child safety seat according to the disclosure from a different angle, with the connector shown as a plug inserted into a side panel through a connector through-slot in the panel; and Fig. 10B is an enlarged partial view of Fig. 10A. Fig. 11 shows a side of the panel facing the pull-out part according to the disclosure. Detailed description

[0021] First of all, in the Fig. 1 and Fig. 2 illustrates a child safety seat according to an embodiment of the disclosure as a whole. As shown, the child safety seat includes a seat portion 200 and a foot pedal 300. The seat portion 200 is a portion that is attached to a car so that a child can sit therein, and the foot pedal 300 is a portion that can extend from a position below the seat portion 200 so that the child can place their feet thereon. A device for connecting the foot pedal 300 to the seat portion 200 is an anti-jump device 100 of the disclosure. The anti-jump device 100 is used to movably connect the foot pedal 300 to the seat portion 200 and can fix the foot pedal 300 in a plurality of different positions relative to the seat portion 200. These positions may be, for example, an extended position and a retracted position along a front-to-rear direction of the seat portion 200. In Fig. 1, for example, the foot pedal 300 is shown in the retracted position, and in Fig. 2 the foot pedal 300 is shown in the extended position.

[0022] During use, the foot pedal 300 may be subjected to impact due to a rear-end collision of the vehicle. One of the functions of the anti-jump device 100 of the disclosure is to prevent the foot pedal 300 from inadvertently disengaging from the locked position upon impact.

[0023] For convenience, hereinafter, the front-to-back direction of the seat is referred to as a longitudinal direction, the left-to-right direction is referred to as a transverse direction, and the up-and-down direction is referred to as a vertical direction.

[0024] The anti-jump device 100 according to the disclosure will now be described in its entirety with reference to Fig. 3A and Fig. 3B described. Fig. 3A is a perspective view of the child safety seat according to the disclosure from a different angle, also showing the anti-jump device 100; and Fig. Figure 3B is an enlarged partial view of Fig. 3A.

[0025] As shown, the anti-jump device 100 includes a pull-out portion 110; a locking portion 120; a pair of fixed base portions 130; a cross brace 140; and a cover 150. The pull-out portion 110 is attached to the foot pedal 300 to allow the foot pedal 300 to move. The fixed base portions 130 are attached to a bottom surface of the seat portion 200. The pull-out portion 110 is configured to move longitudinally along the fixed base portions 130. The locking portion 120 is attached to the center of the bottom surface of the pull-out portion 110, thereby blocking or allowing longitudinal movement of the pull-out portion 110 relative to the fixed base portions 130. The cross brace 140 is disposed between two side walls 131 of the fixed base portions 130. The cover 150 is curved under the pull-out part 110 and forms a space for receiving the locking part 120.

[0026] Now, specific structures of the components of the anti-jump device 100 will be described.

[0027] First, the specific structure of the pull-out part 110 will be described with reference to the Fig. 4A and Fig. 4B and Fig. 7. As shown, the extension part 110 is a plate-like component that extends generally in a transverse direction. A front end of the extension part 110 is attached to the foot pedal 300 so that the foot pedal 300 can move together therewith. In other embodiments, the extension part 110 and the foot pedal 300 can also be manufactured as a unit. On the left and right sides of the extension part 110, a hollow cylindrical component, i.e., a slide rail receiving part 112, is provided, which extends in the longitudinal direction. In use, each of the slide rail receiving parts 112 is provided as a sleeve on a slide rail 133 of each of the fixed base parts 130 (see Fig. 5A, which will be described later) so that the extension part 110 can slide longitudinally with respect to the fixed base parts 130. Restriction slots 111 are formed in a vertically extending plate-like part of the extension part 110. These restricting slots are in the form of longitudinally extending straight slots on the back of the plate-like part. In use, the cover 150 is partially clamped in the restricting slots 111 to restrict and fix the cover 150 and the extension part 110, ensuring the reliability of the restriction and fixation between the cover 150 and the extension part 110.

[0028] Now, the specific structure of the fixed base parts 130 will be described with reference to the Fig. 4A and Fig. 4B. As shown, the fixed base parts 130 have the two side walls 131, and the two side walls 131 are opposite to each other in the transverse direction and have a certain lateral thickness. An oblique cross-section of each side wall 131 is substantially a right-angled triangle, with a long side of the right angle corresponding to a bottom surface of the seat part 200, a short side of the right angle extending downward from the bottom surface of the seat part 200, and an inclined side facing the front and bottom surface of the seat part 200. The two side walls 131 of the fixed base parts 130 can be formed as a unit by means of a connecting part (not shown) therebetween, or they can be attached to the seat part 200 independently of each other. In one embodiment, the side walls 131 are hollow to reduce the overall mass.

[0029] Each of the fixed base parts 130 has a slide rail 133 extending longitudinally (see Fig. 5A), e.g., a cylindrical slide rail 133. In the illustrated embodiment, the slide rail 133 extends forward from the front of each side wall 131. In other embodiments, each of the slide rails 133 may have a different cross-sectional shape, such as a square or other polygonal cross-section. The slide rails 133 may also extend from other parts of the fixed base parts 130, for example, from the outer surfaces of the side walls 131 of the fixed base parts 130.

[0030] Each side wall 131 of the fixed base parts 130 has an inner surface and an outer surface, wherein the inner surfaces are surfaces of the two side walls 131 that face each other, and the outer surfaces are surfaces of the two side walls 131 that face away from each other. The inner surface of each side wall 131 is provided with an insertion slot 132 into which a plug 123 (see Fig. 8) of the locking part 120, thereby locking the extension part 110. A plurality of insertion slots 132 may be formed in the longitudinal direction to provide a plurality of different locking positions for the extension part 110. Each of the insertion slots 132 has a vertical part 132a and a longitudinal part 132b. The vertical part 132a and the longitudinal part 132b extend vertically and longitudinally, respectively, and intersect at a point to form an insertion slot 132 in the shape of an inverted L. The vertical part 132a extends downward from the intersection point, and the longitudinal part 132b extends forward from the intersection point. In this embodiment, the vertical part 132a and the longitudinal part 132b have substantially the same length, but in other embodiments, they may have different lengths.

[0031] Now, the specific structure of the locking part 120 will be described with reference to the Fig. 5A and Fig. 5B and Fig. 8. As shown, the locking member 120 includes a generally square handle 121 and two arms 122 extending from the handle 121. The two arms 122 extend approximately from a lateral center of a rear side of the handle 121 and approximately near the handle 121 in the longitudinal direction, and then the two arms 122 gradually extend laterally and to the left and right, respectively, to form an arc shape of approximately one-quarter of the circumference of the two arms 122, which are symmetrical to each other. The locking member 120 includes plugs 123 disposed at an end of each arm 122 remote from the handle 121. The plugs 123 each extend substantially in the transverse direction and have a uniform lateral cross-sectional shape. The lateral cross-sectional shape of each of the plugs 123 corresponds to the shape of each of the insertion slots 132 in the side walls 131 of the fixed base parts 130 (ie, an L-shape formed by a vertical part 132a and a longitudinal part 132b), and it is slightly smaller than the insertion slot 132 so that the plug 123 can easily slide into the insertion slot 132. The arms 122 are made of a rigid material that can be elastically deformed to a certain extent to allow the arms 122 to be inserted into or withdrawn from sliding guides 151 of the cover 150 (which will be described later).

[0032] Now the cross member 140 is removed with reference to the Fig. 4A to 5B. As shown, the cross brace 140 is a rod-shaped component that is laterally inserted between the two side walls 131. Both ends of the cross brace 140 are inserted through the inner and outer surfaces of the two side walls 131, respectively, and are finally exposed outside the outer surfaces. Both ends of the cross brace 140 are each provided with a stop 141, wherein the stop 141 can be a part of the cross brace 140 with an enlarged diameter in cross-section or an annular component that is slid onto the cross brace 140 as a sleeve. The stops 141 can be clamped to outer sides of the outer surfaces of the side walls 131, thereby limiting movement of the two side walls 131 away from each other.

[0033] If, during use of the child safety seat, the foot pedal 300 is subjected to an impact (in particular, a downward or rearward impact), the foot pedal 300 can transmit the impact force to the extension part 110 and further to the locking part 120. Since the two arms 122 of the locking part 120 have parts that extend laterally, the locking part 120 is able to convert the impact force into a lateral thrust against the side walls 131, in particular from a position inside the side walls 131 to a position outside the side walls 131. In this situation, the side walls 131 can move away from each other, i.e., each outward, so that the plugs 123 of the arms 122 are pulled out of the insertion slot 132 of the side wall 131. As a result, the locking part 120 releases the foot pedal 300 from the locking position, causing a jumping phenomenon.

[0034] Advantageously, compared to the cross brace 140, the movement of the two side walls 131 away from each other is limited, thus effectively preventing the bouncing phenomenon. In particular, when the extension part 110 is compressed by a certain external force, in particular by the occupant stepping down on the extension part 110, the extension part 110 can transmit the impact to the two side walls 131 of the fixed base parts 130, thereby generating a laterally outward thrust on the side walls 131. However, from the outside of the side walls 131, the cross brace 140 limits the movement of the two side walls 131 away from each other, absorbs the impact applied by the extension part 110, and prevents the extension part 110 from leaving the locked position by the side walls 131 moving away from each other.This ensures the stability of the extension part 110 after extension, that is, the stability of the foot pedal 300 after extension is ensured. In particular, when the occupant impacts the foot pedal 300, the extension part 110 will not retract due to jumping, thus ensuring normal use of the foot pedal 300 and also preventing the occupant from being injured by jumping-induced retraction of the extension part 110, thereby improving safety during use.

[0035] The cross brace 140 can be placed at a position in a triangular area under the insertion slot 132 of each of the side walls 131. The Fig. The position shown in Figure 4B, i.e., the position in approximately the first third of the longitudinal length of the side wall 131 and close to the bottom hypotenuse of the side wall 131, is preferred. The diameter of the cross brace 140 can be a maximum of half the length of the vertical side of the side wall 131 (about 43 mm), and a preferred diameter is about one-tenth the length of the vertical side of the side wall 131 (about 8 mm). A length LB of the part of the cross brace 140 located between the two side walls 131 is greater than a length LA and a length LC of the part of the cross brace 140 inserted into each of the side walls 131. In a preferred embodiment, LB = 188 mm and LA = LC = 40 mm.

[0036] Now, the cover 150 is shown with reference to Fig. 6. As shown, the cover 150 is a substantially rectangular component that is curved at the bottom of the extension part 110 and moves together with the extension part 110. The cover 150 is disposed between the two side walls 131 of the fixed base parts 130. In one embodiment, a left and a right edge of the cover 150 are respectively adjacent to the inner surfaces of the two side walls 131 of the fixed base parts 130. The two arms 122 of the locking part 120 are at least partially disposed between the cover 150 and the extension part 110.

[0037] The cover 150 is provided with two sliding guides 151 on the side facing the extension part 110, as shown by dotted lines in the figure. Shapes of the two sliding guides 151 correspond to those of the arms 122 of the locking part 120. That is, the sliding guides 151 extend from the front side edge of the cover 150 near the center, first extending rearward substantially in a longitudinal direction, and then gradually extending transversely (the two sliding guides 151 extend left and right, respectively), forming two arcuate sliding guides 151 extending from the front edge to the two side edges of the cover 150.

[0038] The two arms 122 of the locking part 120 are each received in the two sliding guides 151 of the cover 150, and their movement paths are defined by the sliding guides 151. A longitudinal movement of the handle 121 is translated by the sliding guides 151 into a transverse movement of the plugs 123 at the ends of the arms 122. In particular, when the handle 121 is moved forward (i.e., reaches an unlocked position), the plugs 123 move transversely inward, thereby retracting them into the cover 150; and when the handle 121 is moved backward (i.e., reaches the locked position), the plugs 123 move transversely outward, protruding from the cover 150.

[0039] In one embodiment, the arms 122 of the locking member 120 are memory components that tend to protrude from the cover 150. When the locking member 120 is moved to the unlocked position, the arms 122 move into the cover 150, creating a restoring force toward the locked position. Thus, the elasticity of the arms 122 preloads the locking member 120, causing it to move toward the locked position.

[0040] In another embodiment, another spring member, such as a spring, is disposed between the locking member 120 and the extension member 110. The spring member biases the locking member 120 toward the locked position.

[0041] In the Fig. 9A to 11, the structure of the cover 150 and its positional relationship with the extension part 110 and the fixed base parts 130 are shown.

[0042] Both lateral sides of the cover 150 are each provided with connector through-slots 152. The shapes of the connector through-slots 152 are essentially the same as the cross-sectional shape of the connectors 123, i.e., L-shaped. The connectors 123 can be pulled out of or retracted into the cover 150 via the connector through-slots 152. Therefore, when the plugs 123 protrude from the cover 150, they are located in the plug through slots 152 and the insertion slots 132. In this way, the plugs 123 fix the relative positions of the plug through slots 152 and the insertion slots 132 and thus also the relative positions of the cover 150 and the fixed base parts 130. And since the cover 150 is attached to the extension part 110, the plugs 123 also fix the relative positions of the extension part 110 and the fixed base parts 130.

[0043] The operation of the anti-jump device 100 according to the disclosure will now be described.

[0044] If the user wishes to unlock the foot pedal 300, they must place one hand under the seat part 200 and pull out the handle 121 of the locking part 120 by pushing against the foot pedal 300. In this way, the locking part 120 overcomes the biasing force that biases it toward the locked position, thereby moving it to the unlocked position. At the same time, the arms 122 retract into the cover 150, and the plugs 123 of the locking part 120 leave the insertion slots 132 in the side walls 131 of the fixed base parts 130. In this way, the extension part 110 (and the foot pedal 300) leaves the locking relationship with the fixed base parts 130 (and the seat part 200), allowing the user to move the foot pedal 300 to a corresponding position including the extended position and the retracted position.

[0045] When the user wishes to lock the foot pedal, they must release the handle 121 of the locking member 120 and move the foot pedal 300 to a corresponding position including the extended position and the retracted position so that the plugs 123 on the locking member 120 can be aligned with the insertion slots 132 in the fixed base members 130. Since the locking member 120 is preloaded to move to the locked position, the plugs 123 protrude from the plug passage slots 152 of the cover 150 to be inserted into the insertion slots 132. Since the connectors 123 on the arms 122 are also located in the connector through slots 152, the connectors 123 simultaneously fix the positional relationship between the cover 150 and the fixed base parts 130, so that a locking relationship is created between the extension part 110 (and the foot pedal 300) and the fixed base parts 130 (and the seat part 200). List of reference numbers 100 anti-jump device 110 pull-out part 111 Limit slot 112 Slide rail mounting part 120 locking part 121 handle 122 Arm 123 plugs 130 Fixed base part 131 side wall 132 slot 132a Vertical part 132b Longitudinal part 133 Slide rail 140 cross brace 141 attack 150 cladding 151 sliding guide 152 connector through slot 200 seat part 300 foot pedal

Claims

[1] Anti-jump device (100) with: a pair of fixed base parts (130) arranged symmetrically on both sides, the pair of fixed base parts (130) having slide rails (133) extending along a longitudinal direction and two side walls (131) opposite each other along a transverse direction perpendicular to the longitudinal direction; an extension part (110) movably inserted into the fixed base parts (130) and slidable along the slide rails (133) to move between an extended position and a retracted position with respect to the fixed base parts (130); a locking part (120) configured to engage the fixed base parts (130) and the extension part (110) to fix a position of the extension part (110) relative to the fixed base parts (130), the locking part (120) having a handle (121) and two arms (122), the two arms (122) extending from the handle (121) to the two side walls (131) of the fixed base parts (130); and a cross brace (140) arranged between the two side walls (131) to prevent the two side walls (131) from being laterally offset from each other. [2] Anti-jump device (100) according to claim 1, wherein: both ends of the cross strut (140) are each inserted into outer sides of the two side walls (131) and are fixed to the two side walls (131) by fixed stops (141) on the outer sides in order to prevent a lateral displacement of the two side walls (131) away from each other. [3] The anti-jump device (100) according to claim 1 or 2, wherein the cross member (140) is arranged at a position where one side of the extension part (110) does not interfere with a movement of the extension part (110). [4] Anti-jump device (100) according to one of the preceding claims, further comprising: a cover (150) which is fastened to the pull-out part (110) and is arranged between the cross strut (140) and the pull-out part (110); at least two groups of insertion slots (132) each arranged on opposite surfaces of the two side walls (131) of the fixed base parts (130); and Plug through slots (152) each arranged on both sides of the cover (150) and matching the insertion slots (132), wherein, when the insertion slots (132) are aligned with the plug through slots (152), the locking part (120) is inserted into the insertion slots (132) and the plug through slots (152) so that a position of the extension part (110) is fixed with respect to the fixed base parts (130). [5] Anti-jump device (100) according to claim 4, wherein: the locking part (120) is arranged on a side of the extension part (110) facing the cross member (140) and has a handle (121) and two symmetrically arranged arms (122), wherein the two arms (122) each extend from the handle (121) to the two side walls (131) of the fixed base parts (130) and ends of the two arms (122) are each provided with plugs (123), and when the insertion slots (132) are aligned with the plug through slots (152), the plugs (123) are inserted into the insertion slots (132) and the plug through slots (152). [6] Anti-jump device (100) according to claim 5, wherein: the handle (121) is arranged at a lateral central position of the pull-out part (110), and the two arms (122) are arcuate components which are bent so as to extend approximately in a quarter-circle arc from the lateral center position of the handle (121) to the two side walls (131). [7] Anti-jump device (100) according to claim 5 or 6, wherein: the arms (122) are rigid arms, each of the insertion slots (132) comprises a longitudinal part (132b) and a vertical part (132a), wherein the longitudinal part (132b) and the vertical part (132a) are substantially linear and intersect each other at an intersection point, and each of the plugs (123) has a shape corresponding to the insertion slots (132) in order to be inserted and fitted positively into the insertion slots (132). [8] Anti-jump device (100) according to one of claims 4 to 7, wherein: a group of at least two groups of insertion slots (132) corresponds to the extended position of the extension part (110), and another group of the at least two groups of insertion slots (132) corresponds to the retracted position of the pull-out part (110). [9] Anti-jump device (100) according to one of claims 5 to 8, wherein: two sliding guides (151) are formed in the casing (150), wherein the two sliding guides (151) each extend with approximately a quarter-circle arc to the two side walls (131) in order to receive the two arms (122), thereby defining movement paths of the two arms (122). [10] Anti-jump device (100) according to claim 9, wherein in the extended or retracted position of the extension part (110), the arms (122) of the locking part (120) protrude from the sliding guides (151) and are inserted into the insertion slots (132) and the plug passage slots (152), and by pulling with an external force, the arms (122) of the locking part (120) are retracted into the sliding guides (151) in order to disengage from the insertion slots (132) and the plug passage slots (152), so that the pull-out part (110) slides along the longitudinal direction with respect to the fixed base parts (130). [11] Anti-jump device (100) according to claim 9 or 10, wherein an elastic element is arranged between the locking part (120) and the cover (150), wherein the elastic element applies a restoring force to the locking part (120) so that the two arms (122) of the locking part (120) remain in a state in which they protrude from the sliding guides (151). [12] Anti-jump device (100) according to one of the preceding claims, wherein the cross strut (140) is arranged approximately in a first third of a longitudinal length of the side walls (131), a diameter of the cross member (140) is approximately one-tenth of a length of vertical edges of the side walls (131), and a length of a part of the cross strut (140) between the two side walls (131) is greater than a length of another part of the cross strut (140) which is inserted into each of the side walls (131). [13] Seat footrest device with: a foot pedal (300); and the anti-jump device (100) according to one of the preceding claims, wherein the foot pedal (300) encloses the extension part (110) of the anti-jump device (100). [14] Seat footrest device according to claim 13, wherein: both ends of the cross strut (140) are each inserted into the outer sides of the two side walls (131) and are fixed to the two side walls (131) by fixed stops (141) on the outer sides in order to prevent a lateral displacement of the two side walls (131) away from each other. [15] Seat footrest device according to claim 13 or 14, wherein: the cross strut (140) is arranged at a position where one side of the pull-out part (110) does not impair movement of the pull-out part (110). [16] A seat footrest device according to any one of claims 13 to 15, further comprising: a cover (150) which is fastened to the pull-out part (110) and is arranged between the cross strut (140) and the pull-out part (110); at least two groups of insertion slots (132) each arranged on opposite surfaces of the two side walls (131) of the fixed base parts (130); and Plug through slots (152) which are provided on both sides of the cover (150) and which match the insertion slots (132), wherein when the insertion slots (132) are aligned with the plug through slots (152), the locking part (120) is inserted into the insertion slots (132) and the plug through slots (152) so that a position of the extension part (110) is fixed with respect to the fixed base parts (130). [17] Seat footrest device according to claim 16, wherein: the locking part (120) is arranged on a side of the extension part (110) facing the cross member (140) and has a handle (121) and two symmetrically arranged arms (122), wherein the two arms (122) each extend from the handle (121) to the two side walls (131) of the fixed base parts (130) and ends of the two arms (122) are each provided with plugs (123), and when the insertion slots (132) are aligned with the plug through slots (152), the plugs (123) are inserted into the insertion slots (132) and the plug through slots (152). [18] Seat footrest device according to claim 17, wherein: the handle (121) is arranged at a lateral central position of the pull-out part (110), and the two arms (122) are arcuate components which are bent so as to extend approximately in a quarter-circle arc from the lateral center position of the handle (121) to the two side walls (131). [19] Seat footrest device according to one of claims 13 to 18, wherein: the handle (121) of the locking part (120) of the anti-jump device (100) is exposed on a side of the foot pedal (300) facing the cross brace (140). [20] Child safety seat with: a seat part (200); and the seat footrest device according to one of claims 13 to 19, wherein the foot pedal (300) of the seat footrest device and the anti-jump device (100) are arranged under the seat part (200), the fixed base parts (130) of the anti-jump device (100) are attached to a bottom side of the seat part (200), wherein the longitudinal direction is a front-to-rear direction of the seat part (200) and the transverse direction is a left-to-right direction of the seat part (200), when the pull-out part (110) is in the extended position, the foot pedal (300) protrudes from a bottom side of the seat part (200) to a front side of the seat part (200), and when the pull-out part (110) is in the retracted position, the foot pedal (300) is at least partially located under the bottom side of the seat part (200), and the handle (121) of the locking part (120) of the anti-jump device (100) is exposed under the foot pedal (300).

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