CN219900828U

CN219900828U - Truss forming device

Info

Publication number: CN219900828U
Application number: CN202320960304.7U
Authority: CN
Inventors: 陈振东; 请求不公布姓名
Original assignee: TJK Machinery Tianjin Co Ltd
Current assignee: TJK Machinery Tianjin Co Ltd
Priority date: 2023-04-25
Filing date: 2023-04-25
Publication date: 2023-10-27
Anticipated expiration: 2033-04-25

Abstract

The utility model belongs to the technical field of trusses and discloses a truss forming device which comprises a first fixed support, a first driving assembly, a first movable support, a second fixed support, a second driving assembly and a second movable support.

Description

Truss forming device

Technical Field

The utility model relates to the technical field of trusses, in particular to a truss forming device.

Background

The truss block formed by splicing the single steel bar trusses has the excellent characteristics of strong prefabrication, flexible and changeable combination, reliable finished product structure and the like, and is a steel bar truss which is very widely applied in the field of building engineering.

Before forming, the truss block needs to fix a plurality of single-piece steel bar trusses extending along one direction and a plurality of single-piece steel bar trusses or a plurality of straight bars extending along the other direction, so that the parts to be welded in the two directions are mutually abutted, and then welding or binding operation is performed.

Disclosure of Invention

The utility model aims to provide a truss forming device which can simply and conveniently realize positioning and fixing.

To achieve the purpose, the utility model adopts the following technical scheme:

truss forming device includes:

the first fixing support is provided with a plurality of first positioning parts, and the first positioning parts can correspondingly abut against one sides of the first molding parts one by one;

a first drive assembly;

the first movable bracket is arranged at the output end of the first driving component, a plurality of first abutting parts are arranged on the first movable bracket, and the first driving component can drive the first abutting parts to abut against the other sides of the first forming components in a one-to-one correspondence manner;

the second fixing support is provided with a plurality of second positioning parts, and the second positioning parts can be abutted against one sides of the second molding parts in a one-to-one correspondence manner;

a second drive assembly;

the second movable support is arranged at the output end of the second driving assembly, a plurality of second propping parts are arranged on the second movable support, the second driving assembly can drive a plurality of second propping parts to prop against the other sides of a plurality of second forming parts in a one-to-one correspondence manner, and the second direction and the first direction are arranged at an included angle.

Preferably, the first fixing support comprises a plurality of fixing plates, a notch is formed in each fixing plate, the side wall of each notch is used as the first positioning part, and the bottom wall of each notch can bear the first forming part.

Preferably, the first movable support comprises a synchronous stay and a plurality of movable plates, the movable plates are sequentially fixed on the synchronous stay at intervals along the length direction of the synchronous stay, the synchronous stay is connected with the output end of the first driving assembly, and the side wall of the movable plate is used as the first abutting part.

Preferably, the first fixed support and the first movable support are respectively provided with a plurality of first movable supports, and the plurality of first movable supports are sequentially arranged at intervals along the first direction and are connected to the output end of the first driving assembly.

Preferably, the first driving assembly includes:

a first driving part;

and the linkage rod is connected to the output end of the first driving component, and the plurality of first movable brackets are connected to the linkage rod.

Preferably, the second fixing bracket includes a plurality of fixing components, each of the fixing components including:

a bearing block;

the positioning roller is rotationally connected to the bearing block, the axis is perpendicular to the second direction, and the outer circumferential surface of the positioning roller is used as the second positioning part;

the side blocking roller is rotationally connected to the bearing block, the axis is perpendicular to the second direction, the distance between the positioning roller and the side blocking roller is gradually increased along the direction deviating from the bearing block, and the second forming part can be borne between the positioning roller and the side blocking roller.

Preferably, the second movable bracket includes a plurality of barrier strips, and a side wall of the barrier strips serves as the second abutting portion.

Preferably, the second fixed support and the second movable support are respectively provided with a plurality of second movable supports, and the second movable supports are sequentially arranged at intervals along the second direction and are connected with the output end of the second driving assembly.

Preferably, the second driving assembly includes:

a second driving part;

the second abutting parts of the second movable brackets are arranged on the same synchronizing shaft in a one-to-one correspondence manner;

the transmission mechanism is respectively connected with the output end of the second driving component and the synchronous shafts, and the second driving component can drive the synchronous shafts to synchronously rotate through the transmission mechanism.

Preferably, the second positioning part is provided with at least one guide wheel in the second direction, the axis of the guide wheel is perpendicular to the second direction, and the second molding part can extend into an annular groove on the peripheral wall of the guide wheel.

The utility model has the beneficial effects that:

the first forming part on the first fixed support and the second forming part on the second fixed support can be mutually crossed, the first fixed support, the first driving assembly and the first movable support are mutually matched, a plurality of first forming parts extending in the first direction can be clamped, the second fixed support, the second driving assembly and the second movable support are mutually matched, a plurality of second forming parts extending in the second direction can be clamped, and therefore the first forming parts and the second forming parts which are mutually crossed can be simply and conveniently fixed in position, and subsequent welding or binding forming operation can be facilitated.

Drawings

FIG. 1 is an elevation view of a truss forming apparatus according to an embodiment of the utility model;

FIG. 2 is an enlarged view at A in FIG. 1;

FIG. 3 is a cross-sectional view of a truss forming apparatus according to an embodiment of the utility model;

fig. 4 is an enlarged view at B in fig. 3;

FIG. 5 is a schematic view of a portion of the components of a truss forming apparatus according to an embodiment of the utility model;

FIG. 6 is an enlarged view at C in FIG. 5;

fig. 7 is a top view of a truss forming device according to an embodiment of the utility model.

In the figure:

100. a first molding member; 200. a second molding member;

1. a first fixing bracket;

10. a first positioning portion; 11. a fixing plate; 111. a notch;

2. a first drive assembly;

21. a first driving part; 22. a linkage rod;

3. a first movable bracket;

30. a first abutting portion; 31. synchronizing the stay; 32. a movable plate;

4. a second fixing bracket;

40. a second positioning portion; 41. a bearing block; 42. a positioning roller; 43. a side blocking roller;

5. a second drive assembly;

51. a second driving part; 52. a synchronizing shaft; 53. a transmission mechanism; 531. a transmission frame; 532. a drive rack; 533. a transmission gear;

6. a second movable bracket;

60. a second abutting portion; 61. a barrier strip;

7. forming a seat body;

71. a base; 72. a platform plate;

8. a guide wheel;

9. and forming a mechanical arm.

Detailed Description

Embodiments of the present utility model are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar parts throughout, or parts having like or similar functions. The embodiments described below by referring to the drawings are illustrative and intended to explain the present utility model and should not be construed as limiting the utility model.

In the description of the present utility model, unless explicitly stated and limited otherwise, the terms "connected," "connected," and "fixed" are to be interpreted broadly, as for example, they may be fixedly connected, or may be detachably connected, or may be electrically connected, or may be directly connected, or may be indirectly connected through an intermediary, or may be in communication with one another in two elements or in an interaction relationship between two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

In the description of the present utility model, unless explicitly stated and limited otherwise, a first feature "above" or "below" a second feature may include the first feature and the second feature being in direct contact, or may include the first feature and the second feature not being in direct contact but being in contact by another feature therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

The technical scheme of the utility model is further described below by the specific embodiments with reference to the accompanying drawings.

As shown in fig. 1 to 7, the present utility model provides a truss forming apparatus including a first fixed bracket 1, a first driving assembly 2, a first movable bracket 3, a second fixed bracket 4, a second driving assembly 5, and a second movable bracket 6. The first forming components 100 extending along the first direction can be parallel to each other and sequentially arranged on the first fixing support 1 at intervals, the first fixing support 1 is provided with a plurality of first positioning portions 10, the first positioning portions 10 are sequentially arranged at intervals along the second direction and can be abutted against one side of the first forming components 100 in a one-to-one correspondence manner, the first movable support 3 is arranged at the output end of the first driving component 2, the first movable support 3 is provided with a plurality of first abutting portions 30, the first driving component 2 can drive the first abutting portions 30 to abut against the other side of the first forming components 100 in a one-to-one correspondence manner, the second forming components 200 extending along the second direction can be parallel to each other and sequentially arranged on the second fixing support 4 at intervals, the second fixing support 4 is provided with a plurality of second positioning portions 40, the second positioning portions 40 are sequentially arranged at intervals along the first direction and can be abutted against one side of the first forming components 6, the second positioning portions 40 can be abutted against one side of the second forming components 6 in a one-to-another correspondence manner, the second forming components 200 can be abutted against the first side of the second forming components 60 in a one-to-another manner, and the second positioning portions 60 can be arranged at intervals along the first direction.

In the utility model, the first molding part 100 on the first fixing bracket 1 and the second molding part 200 on the second fixing bracket 4 can be mutually crossed, the first fixing bracket 1, the first driving component 2 and the first movable bracket 3 are mutually matched, a plurality of first molding parts 100 extending in the first direction can be clamped, the second fixing bracket 4, the second driving component 5 and the second movable bracket 6 are mutually matched, a plurality of second molding parts 200 extending in the second direction can be clamped, and therefore, the mutually crossed first molding parts 100 and second molding parts 200 can be simply and conveniently positioned and fixed, and the subsequent welding or binding molding operation is facilitated.

In this embodiment, the first direction and the second direction are perpendicular to each other, the first molding member 100 is a single-piece steel bar truss, and the second molding member 200 is a single-piece steel bar truss. In addition to the above arrangement, the angle between the first direction and the second direction may be set to other angles, for example 80 ° or 100 °, as desired, and the first forming member 100 and the second forming member 200 may be straight bars or other structural members.

Specifically, the truss forming device further comprises a forming base 7, the forming base 7 comprises a base 71 and a platform plate 72, the platform plate 72 is paved on the base 71, the first fixed support 1, the first driving component 2 and the second fixed support 4 are fixedly arranged on the top surface of the platform plate 72, the first movable support 3 is slidably arranged on the top surface of the platform plate 72, the first driving component 2 is fixedly arranged on the base 71, and the first direction and the second direction are parallel to the top surface of the platform plate 72.

Specifically, the first fixing bracket 1 includes a plurality of fixing plates 11, the fixing plates 11 are provided with notches 111, the side walls of the notches 111 serve as the first positioning portions 10, and the bottom walls of the notches 111 can carry the first molding member 100. The device has the advantages of simple structure and convenient processing.

In the present embodiment, the fixing plate 11 is vertically fixed to the top surface of the platform plate 72 and extends parallel to the second direction, and the notch 111 is provided at the top of the side of the fixing plate 11 facing the first driving assembly 2.

Specifically, the first movable bracket 3 includes a synchronization stay 31 and a plurality of movable plates 32, the plurality of movable plates 32 are fixed to the synchronization stay 31 at intervals in sequence along the length direction of the synchronization stay 31, the synchronization stay 31 is connected to the output end of the first driving assembly 2, and the side walls of the movable plates 32 serve as the first abutting portions 30. The above arrangement enables the first driving assembly 2 to drive the plurality of first abutments 30 to move synchronously.

In the present embodiment, the top surface of the platform plate 72 is provided with a guide block, the guide block is provided with a groove penetrating in the second direction, the synchronization stay 31 extends in the second direction, the movable plate 32 is slidably disposed in the groove on the guide block, the movable plate 32 is vertically fixed on the synchronization stay 31 and extends parallel to the second direction, and the fixed plate 11 and the movable plate 32 are disposed in one-to-one correspondence, and the corresponding one fixed plate 11 and one movable plate 32 are disposed in a staggered manner in the first direction.

More specifically, the first fixed support 1 and the first movable support 3 are respectively provided with a plurality of first fixed supports 1, which are sequentially arranged at intervals along the first direction, and the plurality of first movable supports 3, which are sequentially arranged at intervals along the first direction, are all connected to the output end of the first driving component 2. The above arrangement makes one first molding member 100 supported by the plurality of first fixing brackets 1 and clamped in cooperation with the plurality of first movable brackets 3, thereby being more firm and reliable.

In this embodiment, the first fixed brackets 1 and the first movable brackets 3 are disposed in a one-to-one correspondence, and in other embodiments, the number of the first movable brackets 3 may be greater than or less than the number of the first fixed brackets 1.

More specifically, the first driving assembly 2 includes a first driving part 21 and a link lever 22, the link lever 22 is connected to an output end of the first driving part 21, and the plurality of first movable brackets 3 are connected to the link lever 22. The above arrangement enables the plurality of first movable brackets 3 to be driven, and the structure is simple, stable and reliable.

In this embodiment, the linkage rod 22 extends along the first direction, the first driving member 21 is an air cylinder, a piston rod of the air cylinder is connected to a middle portion of one side of the linkage rod 22, and the other side of the linkage rod 22 is respectively connected to the synchronous stays 31 of the plurality of first movable brackets 3.

Specifically, the second fixing bracket 4 includes a plurality of fixing assemblies, each of which includes a bearing block 41, a positioning roller 42, and a side fence roller 43. The positioning roller 42 is rotatably connected to the bearing block 41, the axis is perpendicular to the second direction, the outer peripheral surface of the positioning roller 42 is used as the second positioning portion 40, the side blocking roller 43 is rotatably connected to the bearing block 41, the axis is perpendicular to the second direction, the distance between the positioning roller 42 and the side blocking roller 43 is gradually increased along the direction deviating from the bearing block 41, and the second forming component 200 can be borne between the positioning roller 42 and the side blocking roller 43. A V-shaped groove is formed between the registration roller 42 and the side fence roller 43 so that the second molding member 200 can smoothly slide to intersect with the first molding member 100.

In the present embodiment, the bearing block 41 is provided on the top surface of the platen plate 72, and the axis of the registration roller 42 is perpendicular to the first direction and the second direction.

Specifically, the second movable bracket 6 includes a plurality of stopper bars 61, and the side walls of the stopper bars 61 serve as second abutting portions 60 capable of abutting the second molding member 200 against the registration rollers 42. The device has the advantages of simple structure and convenient processing.

More specifically, the second fixed support 4 and the second movable support 6 are respectively provided with a plurality of second fixed supports 4, which are sequentially arranged at intervals along the second direction, and the second movable supports 6, which are sequentially arranged at intervals along the second direction, are all connected to the output end of the second driving assembly 5. The above arrangement makes one second molding member 200 supported by the plurality of second fixing brackets 4 and clamped in cooperation with the plurality of second movable brackets 6, thereby being more firm and reliable.

In this embodiment, the number of second movable brackets 6 may be greater than the number of second fixed brackets 4, the second fixed brackets 4 are three, the second movable brackets 6 are four, and two second movable brackets 6 are disposed between two adjacent second fixed brackets 4. In other embodiments, the number of second movable brackets 6 may also be equal to or less than the number of second fixed brackets 4.

Specifically, the second driving assembly 5 includes a second driving part 51, a transmission mechanism 53, and a plurality of synchronizing shafts 52. The multiple synchronizing shafts 52 are parallel to each other and sequentially spaced apart, the multiple second abutting portions 60 of the second movable support 6 are disposed on the multiple synchronizing shafts 52 in a one-to-one correspondence manner, the multiple second abutting portions 60 of the second movable support 6 opposite to each other along the second direction are disposed on the same synchronizing shaft 52, the transmission mechanism 53 is respectively connected to the output end of the second driving component 51 and the multiple synchronizing shafts 52, and the second driving component 51 can drive the multiple synchronizing shafts 52 to synchronously rotate through the transmission mechanism 53. The above arrangement enables the second driving member 51 to synchronously drive the plurality of second abutting portions 60 of the plurality of second movable brackets 6 to synchronously rotate to perform abutting positioning of the plurality of second molding members 200.

More specifically, the transmission mechanism 53 includes a transmission frame 531, a transmission rack 532, and a transmission gear 533. The transmission frame 531 is connected to the output end of the second driving component 51, the transmission rack 532 is laid on the transmission frame 531, the transmission gear 533 is disposed on the synchronizing shaft 52, and engaged with the transmission rack 532. The above arrangement makes the transmission more stable and reliable, so that the barrier strip 61 can be rotated efficiently. In other embodiments, the transmission mechanism 53 may be a structure of a driving sprocket, a driven sprocket and a transmission chain, the driven sprocket is disposed on the synchronizing shaft 52, the second driving member 51 is used as a motor and is drivingly connected to the driving sprocket, and the transmission chain is wound around the driving sprocket and the driven sprockets of the synchronizing shafts 52.

In this embodiment, the second driving component 51 is an air cylinder or an elevator device, and is fixedly installed on the base 71 of the forming seat 7, a piston rod of the air cylinder or an elevator screw of the elevator device is connected to the transmission frame 531, a linear guide rail is provided on the base 71, a guide rail of the linear guide rail is fixedly provided on the base 71, a slide block of the linear guide rail is fixedly connected to the transmission frame 531, so that the transmission frame 531 can smoothly move along a first direction, an axial direction of the synchronizing shaft 52 is parallel to a second direction, the synchronizing shaft 52 is rotatably supported on the base 71 through a bearing, the synchronizing shafts 52 are mutually parallel, and are sequentially arranged at intervals along the first direction, two transmission racks 532 are paved on the transmission frame 531, and two transmission gears 533 are sleeved on the synchronizing shaft 52 corresponding to the two transmission racks 532.

Specifically, the truss forming apparatus further includes a guide wheel 8, the second positioning portion 40 is disposed opposite to at least one guide wheel 8 in the second direction, the axis of the guide wheel 8 is perpendicular to the second direction, and the second forming member 200 can be inserted into an annular groove on the outer peripheral wall of the guide wheel 8. By providing the guide wheel 8, the second mould part 200 is enabled to slide more easily into cross abutment with the first mould part 100.

In the present embodiment, the guide wheels 8 are disposed on the top surface of the platform plate 72, the axis extends along the first direction, one guide wheel 8 is disposed on the side of each second fixed bracket 4 facing the first driving assembly 2, and one guide wheel 8 is disposed between two adjacent second movable brackets 6 in the second direction.

More specifically, the truss forming device further comprises forming manipulators 9, two forming manipulators 9 are arranged, the two forming manipulators 9 are located on two opposite sides of the forming base 7, and can perform welding or binding forming operation on the first forming part 100 and the second forming part 200 which are mutually crossed and are positioned and fixed, so that the truss forming device is higher in efficiency and safer and more reliable. The forming manipulator 9 is a manipulator conventional in the art, and the specific structure and working principle thereof are not described herein.

The embodiment also provides a truss positioning and fixing method, which uses the truss forming device and comprises the following steps:

step one, a plurality of first molding members 100 extending along a first direction are arranged on a first fixing bracket 1 in parallel and sequentially at intervals.

Step two, the first driving assembly 2 drives the first movable bracket 3 to move, and the plurality of first abutting parts 30 and the plurality of first positioning parts 10 are matched and clamped to fix the plurality of first forming components 100.

And thirdly, arranging a plurality of second molding parts 200 extending along the second direction on the second fixing bracket 4 in parallel and sequentially at intervals, and intersecting the plurality of first molding parts 100.

Fourth, the second driving assembly 5 drives the second movable bracket 6 to move, and the plurality of second abutting portions 60 and the plurality of second positioning portions 40 are matched to clamp and fix the plurality of second molding components 200.

And fifthly, the forming manipulator 9 performs welding or binding forming operation on the first forming part 100 and the second forming part 200 which are mutually intersected and are positioned and fixed, and the truss block is obtained after forming.

Step six, the second driving assembly 5 drives the second movable bracket 6 to move, the plurality of second abutting portions 60 and the plurality of second positioning portions 40 are away from each other, and the second forming part 200 of the truss block is released.

Step seven, the first driving assembly 2 drives the first movable bracket 3 to move, the plurality of first abutting portions 30 and the plurality of first positioning portions 10 are away from each other, and the first forming part 100 of the truss block is released.

And step eight, removing the truss block from the first fixing bracket 1 and the second fixing bracket 4.

It is to be understood that the above examples of the present utility model are provided for clarity of illustration only and are not limiting of the embodiments of the present utility model. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the utility model are desired to be protected by the following claims.

Claims

1. Truss forming device, its characterized in that includes:

the first fixing support (1), a plurality of first forming components (100) extending along a first direction can be mutually parallel and sequentially arranged on the first fixing support (1) at intervals, a plurality of first positioning parts (10) are arranged on the first fixing support (1), and the plurality of first positioning parts (10) can correspondingly abut against one side of the plurality of first forming components (100) one by one;

a first drive assembly (2);

the first movable support (3) is arranged at the output end of the first driving assembly (2), a plurality of first propping parts (30) are arranged on the first movable support (3), and the first driving assembly (2) can drive the plurality of first propping parts (30) to prop against the other sides of the plurality of first forming components (100) in a one-to-one correspondence manner;

the second fixing support (4) is provided with a plurality of second positioning parts (40), and the second positioning parts (40) can be abutted against one side of the second forming parts (200) in a one-to-one correspondence manner;

a second drive assembly (5);

the second movable support (6) is arranged at the output end of the second driving assembly (5), a plurality of second propping parts (60) are arranged on the second movable support (6), the second driving assembly (5) can drive a plurality of second propping parts (60) to be propped against the other side of the second forming part (200) in a one-to-one correspondence manner, and the second direction and the first direction are arranged in an included angle manner.

2. Truss forming device according to claim 1, characterized in that the first fixing bracket (1) comprises a plurality of fixing plates (11), wherein notches (111) are arranged on the fixing plates (11), the side walls of the notches (111) serve as the first positioning parts (10), and the bottom walls of the notches (111) can bear the first forming part (100).

3. Truss forming device according to claim 1, characterized in that the first movable support (3) comprises a synchronization stay (31) and a plurality of movable plates (32), wherein the movable plates (32) are fixed on the synchronization stay (31) at intervals in sequence along the length direction of the synchronization stay (31), the synchronization stay (31) is connected to the output end of the first driving assembly (2), and the side wall of the movable plate (32) is used as the first abutting part (30).

4. Truss forming device according to claim 1, characterized in that the first fixed support (1) and the first movable support (3) are respectively provided with a plurality of first movable supports (3) which are sequentially arranged at intervals along the first direction and are connected to the output end of the first driving assembly (2).

5. Truss forming device according to claim 4, characterized in that the first drive assembly (2) comprises:

a first driving member (21);

and the linkage rod (22) is connected to the output end of the first driving component (21), and the plurality of first movable brackets (3) are connected to the linkage rod (22).

6. Truss forming device according to claim 1, characterized in that said second fixing bracket (4) comprises a plurality of fixing assemblies, each comprising:

a carrier block (41);

a positioning roller (42) rotatably connected to the bearing block (41), the axis of which is perpendicular to the second direction, the outer circumferential surface of the positioning roller (42) serving as the second positioning portion (40);

and the side blocking roller (43) is rotationally connected with the bearing block (41), the axis is perpendicular to the second direction, the distance between the positioning roller (42) and the side blocking roller (43) is gradually increased along the direction deviating from the bearing block (41), and the second forming component (200) can be borne between the positioning roller (42) and the side blocking roller (43).

7. Truss forming device according to claim 1, characterized in that the second movable support (6) comprises a plurality of bars (61), the side walls of the bars (61) being the second abutment (60).

8. Truss forming device according to claim 1, characterized in that the second fixed support (4) and the second movable support (6) are respectively provided with a plurality of second movable supports (6) which are sequentially arranged at intervals along the second direction and are connected to the output end of the second driving assembly (5).

9. Truss forming device according to claim 8, characterized in that the second drive assembly (5) comprises:

a second driving member (51);

the plurality of synchronous shafts (52) are parallel to each other and are sequentially arranged at intervals, a plurality of second abutting parts (60) of the second movable support (6) are arranged on the plurality of synchronous shafts (52) in a one-to-one correspondence manner, and the second abutting parts (60) of the plurality of second movable supports (6) which are opposite to each other along the second direction are arranged on the same synchronous shaft (52);

and the transmission mechanism (53) is respectively connected with the output end of the second driving component (51) and the plurality of synchronous shafts (52), and the second driving component (51) can drive the plurality of synchronous shafts (52) to synchronously rotate through the transmission mechanism (53).

10. Truss-forming device according to any of claims 1-9, further comprising a guide wheel (8), said second positioning section (40) being arranged opposite at least one of said guide wheels (8) in said second direction, the axis of said guide wheel (8) being perpendicular to said second direction, said second forming member (200) being able to extend into an annular groove in the peripheral wall of said guide wheel (8).