CN219668018U

CN219668018U - Supporting leg assembly of child safety seat

Info

Publication number: CN219668018U
Application number: CN202320908037.9U
Authority: CN
Inventors: 王云
Original assignee: Ningbo Bewell Baby Products Manufacturing Co ltd
Current assignee: Ningbo Bewell Baby Products Manufacturing Co ltd
Priority date: 2023-04-21
Filing date: 2023-04-21
Publication date: 2023-09-12
Anticipated expiration: 2033-04-21

Abstract

The utility model provides a supporting leg assembly of a child safety seat, which comprises a base and supporting legs, wherein a front telescopic mechanism, a rear telescopic mechanism and a rotating mechanism are arranged between the base and the supporting legs, a locking mechanism is arranged on the front telescopic mechanism and the rear telescopic mechanism and is driven by the rotating mechanism to act, when the supporting legs are unfolded downwards, the locking mechanism can lock the front telescopic mechanism and the rear telescopic mechanism, and when the supporting legs are folded upwards, the locking mechanism unlocks the front telescopic mechanism and the rear telescopic mechanism. According to the utility model, the front-back telescopic mechanism and the rotating mechanism are combined together through the locking mechanism, so that the support legs can not move back and forth when supporting the safety seat, and can only move back and forth after being folded upwards, and the stability of the support legs for supporting the safety seat is improved.

Description

Supporting leg assembly of child safety seat

Technical Field

The present utility model relates to the technical field of child safety seats, and more particularly to a support leg assembly for a child safety seat.

Background

Child safety seats typically have support leg assemblies at the front end of the base for supporting the safety seat and strengthening the stability of the safety seat. In the prior art, the supporting leg assembly is usually provided with a front-back telescopic mechanism, the length of the supporting leg extending out of the front end of the base is adjustable, the supporting leg is convenient to adapt to the space in the vehicle, and the supporting leg assembly is further provided with a rotating mechanism, so that the supporting leg can be folded upwards in a rotating way and stored below the base, and the packaging and the transportation are convenient. In the prior art, the front-back telescopic mechanism of the supporting leg is an independent mechanism, and the supporting leg can also stretch back and forth when supporting the safety seat, so that the safety seat is unstable, and safety accidents such as tipping over and falling of the seat can easily occur. Although the locking structure is arranged on some products of the safety seat, the front-back telescopic mechanisms of the supporting legs can be limited, the locking structure is required to be unlocked and locked every time the supporting legs are adjusted, the operation is complicated, the locking operation is easy to forget after the supporting legs are adjusted, and the supporting legs cannot stably support the safety seat.

Disclosure of Invention

The utility model aims to solve the technical problem of providing a supporting leg assembly of a child safety seat, which combines a front-back telescopic mechanism with a rotating mechanism, so that the supporting leg cannot move back and forth when supporting the safety seat, and can only move back and forth after the supporting leg is folded upwards, thereby improving the stability of the supporting leg for supporting the safety seat.

The technical scheme is that the supporting leg assembly of the child safety seat comprises a base and supporting legs, wherein a front-back telescopic mechanism is arranged between the base and the supporting legs and is used for enabling the supporting legs to be connected to the base and to move back and forth on the base to be telescopic; a rotating mechanism is arranged between the supporting legs and the front-back telescopic mechanisms, and the rotating mechanism is used for enabling the supporting legs to be connected to the front-back telescopic mechanisms and enabling the supporting legs to rotate relative to the base so as to be folded upwards or unfolded downwards; the front-back telescopic mechanism is provided with a locking mechanism, the locking mechanism is driven by the rotating mechanism to act, when the supporting legs are unfolded downwards, the locking mechanism can lock the front-back telescopic mechanism, and when the supporting legs are folded upwards, the locking mechanism unlocks the front-back telescopic mechanism.

Compared with the prior art, the supporting leg assembly of the child safety seat has the following advantages: a locking mechanism is arranged on the front and rear telescopic mechanisms and is driven by the rotating mechanism to act, namely, the front and rear telescopic mechanisms and the rotating mechanism are combined together; when the supporting legs are unfolded downwards, the locking mechanism can lock the front-back telescopic mechanism, so that the supporting legs cannot move forwards and backwards when supporting the safety seat, and the stability of the supporting legs for supporting the safety seat is improved; when the supporting legs are folded upwards, the locking mechanism unlocks the front-back telescopic mechanism, and the supporting legs can move forwards and backwards at the moment, so that the length of the supporting legs extending out of the front end of the base is conveniently adjusted to adapt to the space in the vehicle.

Preferably, the locking mechanism comprises an inserting sheet and an inserting sheet pull rod, an oblique sliding hole is formed in the inserting sheet, a plug is arranged at the bottom of the inserting sheet, the inserting sheet pull rod is in sliding connection with the oblique sliding hole and is matched with the rotating mechanism, the front-back telescopic mechanism limits the inserting sheet horizontally and limits the inserting sheet pull rod vertically, and the rotating mechanism can drive the inserting sheet pull rod to slide along the oblique sliding hole in the rotating process of the supporting leg so as to push the inserting sheet to move up and down; the base is provided with at least one locking jack which can be in plug-in fit with the plug; when the supporting legs are unfolded downwards, the inserting sheets move downwards, and the plug can be inserted into any locking jack to lock the front-back telescopic mechanism; when the supporting legs are folded upwards, the inserting pieces move upwards, and the plug retreats from the locking jack to unlock the front-back telescopic mechanism. By adopting the structure, the horizontal movement of the insert pull rod is converted into the vertical movement of the insert through the sliding fit between the insert pull rod and the inclined slide hole, so that the rotary mechanism can conveniently control the locking mechanism to act.

Preferably, the inserting piece pull rod is provided with an elastic piece, and the front-back telescopic mechanism limits the elastic piece in the vertical direction; when the supporting legs are folded upwards, the rotating mechanism is contacted with the inserting piece pull rod and drives the inserting piece pull rod to move so that the elastic piece is elastically deformed; when the supporting legs are unfolded downwards, the rotating mechanism is separated from contact with the inserting sheet pull rod, and the elastic piece rebounds to enable the inserting sheet pull rod to reversely move and reset. By adopting the structure, the elastic piece can ensure that the supporting leg can not move back and forth when supporting the safety seat, and the complexity of the connecting structure between the rotating mechanism and the inserting piece pull rod is reduced.

Preferably, the inserting sheet pull rod is connected with a pull rod driving piece, and the front end of the pull rod driving piece is provided with a push rod; the rotating mechanism comprises a rotating shaft arranged on the front-back telescopic mechanism and a supporting leg sleeve head arranged at the upper end of the supporting leg, the supporting leg sleeve head is connected to the rotating shaft and can rotate around the rotating shaft, and a push rod driving structure is arranged on the supporting leg sleeve head; when the supporting legs are folded upwards, the push rod driving structure can be matched with the push rod to push the push rod to move, so that the pull rod driving piece pulls the inserting piece pull rod to move; when the support legs are deployed downward, the push rod driving structure is out of contact with the push rod. By adopting the structure, the pull rod driving piece is matched with the rotating mechanism, so that the structural complexity of the inserting piece pull rod is reduced, the pull rod driving piece can have a certain rotating space under the driving of the rotating mechanism, and the pull rod driving piece can not enable the inserting piece pull rod to move in the vertical direction when rotating.

Preferably, the front-back telescopic mechanism comprises a guide bar arranged on the base and a sliding piece arranged at the upper end of the supporting leg, the sliding piece is in sliding fit with the guide bar, and the locking mechanism is arranged at the side part of the sliding piece; the sliding piece is provided with a rotating shaft connecting part, and the rotating shaft is connected to the rotating shaft connecting part. By adopting the structure, the rotating shaft is connected to the rotating shaft connecting part of the sliding part, and the locking mechanism is arranged on the side part of the sliding part, so that the assembly is convenient.

Preferably, the side part of the sliding piece is provided with a guiding convex strip, the pull rod driving piece is in sliding fit with the guiding convex strip, and the guiding convex strip guides the pull rod driving piece. By adopting the structure, the pull rod driving piece is beneficial to pulling the inserting sheet pull rod to move horizontally.

Preferably, the sliding piece is provided with a limiting structure, and the limiting structure is used for limiting the push rod driving structure when the supporting legs are unfolded downwards. By adopting the structure, the limiting structure limits the push rod driving structure when the supporting legs are unfolded downwards, so that the supporting legs can be prevented from being unfolded and rotated excessively, and the supporting legs can be prevented from being rotated outwards when the safety seat is supported.

Preferably, the outer side of the sliding piece is provided with a sliding piece sleeve, the inner top side of the sliding piece sleeve is provided with at least one pair of reverse hooks, the top of the sliding piece is provided with a clamping hole, and at least one pair of reverse hooks are clamped in the clamping hole; the locking mechanism is arranged between the side part of the sliding piece and the inner side wall of the sliding piece sleeve. By adopting the structure, the sliding piece sleeve is in buckle connection with the sliding piece, so that the assembly is convenient; providing a slider pocket is advantageous for protecting the locking mechanism.

Preferably, the inside wall of the slider sleeve is provided with a locking mechanism installation position, the locking mechanism is arranged in the locking mechanism installation position, the locking mechanism installation position comprises an inserting sheet sliding chute for enabling the inserting sheet to slide in the vertical direction, an inserting sheet pull rod sliding chute for enabling the inserting sheet pull rod to slide in the horizontal direction, and an elastic piece sliding chute for enabling the elastic piece to move in the horizontal direction in a telescopic manner, and an inserting sheet telescopic slot is arranged at the bottom of the inserting sheet sliding chute and is used for enabling the plug to extend out of or retract into the slider sleeve. By adopting the structure, the locking mechanism can be arranged in the installation position of the locking mechanism, and then the sliding piece sleeve is clamped on the sliding piece, so that the assembly is convenient.

Preferably, a sliding groove is respectively arranged on two sides of the guide bar on the base, two sides of the sliding piece sleeve are respectively in sliding fit with the two sliding grooves, and the locking insertion holes are arranged on the groove walls of the sliding grooves. By adopting the structure, the locking jack is arranged on the groove wall of the chute, the chute is assembled on the base, the processing procedure is avoided from being increased due to the fact that the structure of the base is too complex, and the chute is simple to process and convenient to assemble.

Drawings

Fig. 1 is an exploded structural view of a support leg assembly of the child safety seat of the present utility model.

Fig. 2 is another exploded structural view of the support leg assembly of the child safety seat of the present utility model.

Fig. 3 is an enlarged schematic view of the area B in fig. 2.

Fig. 4 is an exploded schematic view of the assembled structure of the locking mechanism of fig. 3.

Fig. 5 is an enlarged schematic view of the area a in fig. 1.

As shown in the figure: 1. the device comprises a base, 1-1, a guide bar, 1-2, a chute, 1-21, a locking jack, 2, a supporting leg, 3, a sliding piece, 3-1, an inserting piece telescopic slot, 3-2, a rotating shaft connecting part, 3-3, a limiting structure, 3-4, a guide convex strip, 3-5, a clamping hole, 4, a sliding piece sleeve, 4-1, a locking mechanism installation position, 4-2, a clamping hook, 5, an inserting piece, 5-1, an oblique sliding hole, 6, an inserting piece pull rod, 6-1, a convex column, 6-2, a limiting step surface, 6-3, a connecting hole, 7, a spring, 8, a pull rod driving piece, 8-1, a push rod, 9, a supporting leg sleeve head, 9-1, a push rod driving structure and 10 and a rotating shaft.

Detailed Description

For a better understanding of the utility model, various aspects of the utility model will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is merely illustrative of exemplary embodiments of the utility model and is not intended to limit the scope of the utility model in any way. Like reference numerals refer to like elements throughout the specification.

In the drawings, the thickness, size and shape of the object have been slightly exaggerated for convenience of explanation. The figures are merely examples and are not drawn to scale.

It will be further understood that the terms "comprises," "comprising," "includes," "including" and/or "having," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Furthermore, when an expression such as "… at least one" occurs after a list of features listed, the entire listed feature is modified rather than modifying a separate element in the list.

As shown in fig. 1 and 2, the supporting leg assembly of the child safety seat of the present utility model includes a base 1 and a supporting leg 2, a front-rear telescopic mechanism is provided between the base 1 and the supporting leg 2, a rotating mechanism is provided between the supporting leg 2 and the front-rear telescopic mechanism, and a locking mechanism is provided on the front-rear telescopic mechanism, and is driven by the rotating mechanism to act.

The front-back telescopic mechanism comprises a guide bar 1-1 and a chute 1-2 which are arranged on a base 1, and a sliding piece 3 and a sliding piece sleeve 4 which are arranged at the upper end of a supporting leg 2. As shown in fig. 1, two sliding grooves 1-2 are respectively arranged on two sides of the guide strip 1-1, and a gap serving as a slideway is arranged between the two sliding grooves 1-2 and the guide strip 1-1. As shown in fig. 4, a pair of spaced opposite hooks 4-2 are provided on the inner top side of the slider case 4, a clamping hole 3-5 is provided on the top of the slider 3, and two opposite hooks 4-2 are simultaneously clamped in the clamping hole 3-5. The sliding piece 3 and the sliding piece sleeve 4 are both positioned in the slide way, the sliding piece 3 is in sliding fit with the guide strip 1-1, and the sliding piece sleeve 4 is in sliding fit with the two slide grooves 1-2, so that the supporting leg 2 is connected to the base 1. The supporting legs 2 can move back and forth on the base 1 to stretch and retract through the sliding parts 3 and the sliding part sleeves 4 sliding back and forth along the sliding ways.

As shown in fig. 2 and 3, the front end of the slider 3 is provided with a rotation shaft connection part 3-2, a rotation shaft 10 is provided on the rotation shaft connection part 3-2, the upper ends of the support legs 2 are sleeved with support leg sleeves 9, the support leg sleeves 9 are connected to the rotation shaft 10, and the support legs 2 can rotate around the rotation shaft 10 together with the support leg sleeves 9. The rotating mechanism consists of a rotating shaft 10 and a supporting leg sleeve head 9, so that the supporting legs 2 are connected to the sliding piece 3, and the supporting legs 2 can rotate relative to the base 1, and the safety seat can be folded upwards and stored under the base 1 or unfolded downwards and supported.

As shown in fig. 3 and 4, a locking mechanism installation position 4-1 is provided on the inner side wall of the slider sleeve 4, and the locking mechanism installation position 4-1 includes an insert sheet chute, an insert sheet pull rod chute, an elastic member chute, and a pull rod driving member chute which are sequentially provided. The locking mechanism is arranged between the side part of the sliding piece 3 and the inner side wall of the sliding piece sleeve 4 and comprises an inserting piece 5, an inserting piece pull rod 6, a spring 7 and a pull rod driving piece 8.

The inserting piece 5 is arranged in the inserting piece sliding groove and can slide up and down in the vertical direction, an inclined sliding hole 5-1 is formed in the inserting piece 5, a plug is arranged at the bottom of the inserting piece 5, an inserting piece telescopic slot 3-1 is formed in the bottom of the inserting piece sliding groove, and when the inserting piece 5 slides up and down, the plug stretches out or retracts into the slider sleeve 4 through the inserting piece telescopic slot 3-1.

The insert pull rod 6 is arranged in the insert pull rod chute and can slide back and forth in the horizontal direction, the insert pull rod 6 is provided with a convex column 6-1, and the convex column 6-1 is inserted into the inclined slide hole 5-1 and can slide along the inclined slide hole 5-1.

The spring 7 is sleeved on the inserting piece pull rod 6 and is arranged in the elastic piece sliding groove, the limiting step surface 6-2 is arranged in the middle of the inserting piece pull rod 6, two ends of the spring 7 respectively abut against the front end in the elastic piece sliding groove and the limiting step surface 6-2, and the spring 7 can stretch back and forth in the horizontal direction in the elastic piece sliding groove.

The pull rod driving piece 8 is processed by steel wires, the front end of the insert pull rod 6 is provided with a connecting hole 6-3, and two end parts of the pull rod driving piece 8 are respectively connected in the connecting holes 6-3 of the two insert pull rods 6 positioned at two sides of the sliding piece 3. The lateral part of slider 3 is provided with direction sand grip 3-4, and the rear portion and the equal sliding fit of pull rod driver spout and direction sand grip 3-4 of pull rod driver 8, and pull rod driver 8 can slide back and forth in the horizontal direction, all support and guide pull rod driver 8 along pull rod driver spout and direction sand grip 3-4.

The front end of the pull rod driving piece 8 is provided with a push rod 8-1, the supporting leg sleeve head 9 is provided with a push rod driving structure 9-1, when the supporting leg 2 is folded upwards for storage, the push rod driving structure 9-1 rotates forwards and pushes the push rod 8-1 to move forwards in cooperation with the push rod 8-1, so that the pull rod driving piece 8 pulls the inserting sheet pull rod 6 to move forwards, in the process, the spring 7 is compressed, the protruding column 6-1 slides towards the lower end of the inclined sliding hole 5-1 along the inclined sliding hole 5-1, so that the inserting sheet 5 is pushed to move upwards, the plug retracts into the sliding piece sleeve 4 through the inserting sheet telescopic slot 3-1, namely, the rotating mechanism drives the locking mechanism to unlock the front-back telescopic mechanism, and at the moment, the front-back telescopic mechanism can act to enable the supporting leg 2 to move forwards and backwards on the base 1 to be telescopic.

When the supporting leg 2 is unfolded downwards to support, the push rod driving structure 9-1 rotates backwards and is separated from contact with the push rod 8-1, the spring 7 rebounds to push the insert pull rod 6 to move backwards, in the process, the convex column 6-1 slides along the inclined sliding hole 5-1 to the upper end of the inclined sliding hole 5-1 to push the insert 5 to move downwards, the plug extends out of the slider sleeve 4 through the insert telescopic slot 3-1, a plurality of locking jacks 1-21 are formed in the lower side slot wall of the sliding slot 1-2, as shown in fig. 5, the plug can be inserted into the locking jacks 1-21 after extending out of the slider sleeve 4, so that the slider 3 and the slider sleeve 4 are locked with the sliding slot 1-2, at the moment, the front-back telescopic mechanism cannot act, and the supporting leg 2 cannot move forwards and backwards on the base 1 to be telescopic. The limiting structure 3-3 is arranged on the sliding piece 3, and when the supporting leg 2 is unfolded downwards, the limiting structure 3-3 limits the push rod driving structure 9-1, so that the supporting leg 2 is prevented from rotating excessively.

In other embodiments, the spring 7 may not be provided, so that the push rod driving structure 9-1 is connected with the push rod 8-1, and the push rod driving structure 9-1 drives the push rod 8-1 to move back and forth in the process of back and forth rotation, so that the pull rod driving member 8 pulls the insert pull rod 6 to move back and forth.

The foregoing is merely exemplary of the present utility model and is not intended to limit the scope of the present utility model; modifications and equivalent substitutions are intended to be included in the scope of the claims without departing from the spirit and scope of the present utility model.

Claims

1. The supporting leg assembly of the child safety seat comprises a base (1) and supporting legs (2), wherein a front-back telescopic mechanism is arranged between the base (1) and the supporting legs (2), and the front-back telescopic mechanism is used for enabling the supporting legs (2) to be connected to the base (1) and capable of moving back and forth on the base (1) to be telescopic; the folding device is characterized in that a rotating mechanism is arranged between the supporting leg (2) and the front-back telescopic mechanism, and the rotating mechanism is used for enabling the supporting leg (2) to be connected to the front-back telescopic mechanism and enabling the supporting leg (2) to rotate relative to the base (1) so as to be folded upwards or unfolded downwards; the front-back telescopic mechanism is provided with a locking mechanism, the locking mechanism is driven by the rotating mechanism to act, when the supporting legs (2) are unfolded downwards, the locking mechanism can lock the front-back telescopic mechanism, and when the supporting legs (2) are folded upwards, the locking mechanism unlocks the front-back telescopic mechanism.

2. The child safety seat supporting leg assembly according to claim 1, wherein the locking mechanism comprises an insert (5) and an insert pull rod (6), an inclined slide hole (5-1) is formed in the insert (5), a plug is arranged at the bottom of the insert (5), the insert pull rod (6) is slidably connected with the inclined slide hole (5-1) and is matched with the rotating mechanism, the front-back telescopic mechanism limits the insert (5) horizontally and limits the insert pull rod (6) vertically, and the rotating mechanism can drive the insert pull rod (6) to slide along the inclined slide hole (5-1) in the rotating process of the supporting leg (2) so as to push the insert (5) to move up and down; the base (1) is provided with at least one locking jack (1-21) which can be in plug-in fit with the plug; when the supporting legs (2) are unfolded downwards, the inserting pieces (5) move downwards, and the plug can be inserted into any locking jacks (1-21) to lock the front-back telescopic mechanisms; when the supporting legs (2) are folded upwards, the inserting pieces (5) move upwards, and the plug exits the locking jacks (1-21) to unlock the front-rear telescopic mechanism.

3. The supporting leg assembly of the child safety seat according to claim 2, wherein the insert pull rod (6) is provided with an elastic member, and the front-rear telescopic mechanism limits the elastic member in a vertical direction; when the supporting leg (2) is folded upwards, the rotating mechanism is contacted with the inserting piece pull rod (6) and drives the inserting piece pull rod (6) to move so that the elastic piece is elastically deformed; when the supporting legs (2) are unfolded downwards, the rotating mechanism is separated from contact with the inserting piece pull rod (6), and the elastic piece rebounds to enable the inserting piece pull rod (6) to reversely move and reset.

4. A child safety seat support leg assembly according to claim 3, wherein the insert pull rod (6) is connected with a pull rod driving member (8), and the front end of the pull rod driving member (8) is provided with a push rod (8-1); the rotating mechanism comprises a rotating shaft (10) arranged on the front-back telescopic mechanism and a supporting leg sleeve head (9) arranged at the upper end of the supporting leg (2), the supporting leg sleeve head (9) is connected to the rotating shaft (10) and can rotate around the rotating shaft (10), and a push rod driving structure (9-1) is arranged on the supporting leg sleeve head (9); when the supporting leg (2) is folded upwards, the push rod driving structure (9-1) can be matched with the push rod (8-1) to push the push rod (8-1) to move, so that the pull rod driving piece (8) pulls the inserting piece pull rod (6) to move; when the support leg (2) is unfolded downwards, the push rod driving structure (9-1) is separated from contact with the push rod (8-1).

5. The child safety seat support leg assembly according to claim 4, wherein the front-rear telescopic mechanism comprises a guide bar (1-1) provided on the base (1) and a slider (3) provided on an upper end of the support leg (2), the slider (3) being slidably engaged with the guide bar (1-1), the locking mechanism being provided on a side portion of the slider (3); the sliding piece (3) is provided with a rotating shaft connecting part (3-2), and the rotating shaft (10) is connected to the rotating shaft connecting part (3-2).

6. The child safety seat support leg assembly according to claim 5, wherein the side of the slider (3) is provided with guiding ribs (3-4), the pull rod driver (8) being in sliding engagement with the guiding ribs (3-4), the guiding ribs (3-4) guiding the pull rod driver (8).

7. A child safety seat support leg assembly according to claim 5, wherein the slider (3) is provided with a limit structure (3-3), the limit structure (3-3) being adapted to limit the push rod driving structure (9-1) when the support leg (2) is deployed downwards.

8. The child safety seat support leg assembly according to claim 5, wherein a slider sleeve (4) is provided on the outer side of the slider (3), at least one pair of opposite hooks (4-2) is provided on the inner top side of the slider sleeve (4), a clamping hole (3-5) is provided on the top of the slider (3), and at least one pair of opposite hooks (4-2) are clamped in the clamping hole (3-5); the locking mechanism is arranged between the side part of the sliding piece (3) and the inner side wall of the sliding piece sleeve (4).

9. The child safety seat support leg assembly according to claim 8, wherein a locking mechanism mounting position (4-1) is provided on an inner side wall of the slider sleeve (4), the locking mechanism is provided in the locking mechanism mounting position (4-1), the locking mechanism mounting position (4-1) includes a tab slide groove for sliding the tab (5) in a vertical direction, a tab pull rod slide groove for sliding the tab pull rod (6) in a horizontal direction, and an elastic member slide groove for making the elastic member move telescopically in a horizontal direction, and a tab expansion slot (3-1) is provided at a bottom of the tab slide groove, and the tab expansion slot (3-1) is used for extending or retracting the plug into the slider sleeve (4).

10. The child safety seat support leg assembly according to claim 9, wherein one sliding groove (1-2) is provided on the base (1) on each side of the guide bar (1-1), each side of the slider sleeve (4) is slidably fitted with two sliding grooves (1-2), and the locking insertion holes (1-21) are provided on the groove walls of the sliding grooves (1-2).