Combined building curtain wall

Abstract

The invention discloses a combined building curtain wall, and relates to the technical field of building curtain walls. The curtain wall comprises a curtain wall body, a cavity is formed in the curtain wall body, a lead screw is arranged in the cavity, two movable blocks are arranged on the lead screw in a threaded mode, two movable grooves penetrate through the inner wall of the cavity, an extrusion block is movably arranged on one side of the interior of the cavity, and connecting arms are hinged to the positions, matched with the movable grooves, between the extrusion block and the movable blocks; two fixed blocks are oppositely fixed to the side, away from the extrusion block, of the interior of the cavity, first connecting pieces and second connecting pieces are arranged on the fixed blocks, the extrusion block is matched with the first connecting pieces, the first connecting pieces are matched with the second connecting pieces, and the two movable blocks are conveniently adjusted to be close to each other through a lead screw; and the extrusion blocks are extruded outwards until the extrusion blocks penetrate through the movable grooves and move into the cavities of the adjacent curtain wall bodies, the first connecting pieces are extruded, and meanwhile the second connecting pieces are extruded, so that the adjacent curtain wall bodies are connected together.

Description

Technical Field

[0001] The invention belongs to the technical field of building curtain walls, and in particular relates to a combined building curtain wall. Background Art

[0002] The building curtain wall is composed of a supporting structure system and panels. It has a certain displacement capacity relative to the main structure. It is an external protective structure or decorative structure of the building that does not share the effects on the main structure. It is a non-load-bearing exterior wall enclosure of a building. It is usually composed of panels (glass, metal plates, stone slabs, ceramic plates, etc.) and the supporting structure behind it (aluminum beams and columns, steel structures, glass ribs, etc.). It is a lightweight wall with decorative effects commonly used in modern large and high-rise buildings.

[0003] At present, traditional curtain walls are set up separately. When laying the building curtain walls, it is necessary to connect and fix the adjacent curtain walls with a large number of bolts. The curtain walls cannot be spliced ​​and fixed by the curtain walls themselves. As a result, the installation of the building curtain walls requires tightening a large number of bolts, which is cumbersome, labor-intensive and inefficient.

[0004] To this end, we designed a modular building curtain wall to solve the above problems. Summary of the invention

[0005] To solve the above technical problems, the present invention is achieved through the following technical solutions:

[0006] The present invention is a modular building curtain wall, comprising a curtain wall body, a cavity is provided inside the curtain wall body, a screw rod is provided inside the cavity, two movable blocks are threadedly provided on the screw rod, two movable grooves are penetrated through the inner wall of the cavity, an extrusion block is movably provided on one side of the cavity, and cooperates with the movable groove, a connecting arm is hinged between the extrusion block and the movable block, two fixed blocks are relatively fixed on one side of the cavity away from the extrusion block, and a first connecting member and a second connecting member are provided on the fixed block;

[0007] A second bevel gear is arranged on one side of the outer wall of the screw rod, and the first bevel gear is meshed with the rear side of the second bevel gear.

[0008] The first connecting member includes a first fixing rod, which is fixedly connected to a fixing block, a first movable plate is movably sleeved on the first fixing rod, a first spring is connected between the first movable plate and the fixing block, the first spring is sleeved on the outside of the first fixing rod, a fixing plate is fixed to one end of the first movable plate close to the inner wall of the cavity, an extrusion head is fixed to one end of the fixing plate close to the through groove, the extrusion head and the extrusion block cooperate with each other, and an end of the fixing plate away from the extrusion head is an inclined structure.

[0009] The ends of the extrusion head and the extrusion block that are close to each other are both arc-shaped structures, a through hole and a socket are provided on the side of the curtain wall body surface close to the fixed block, a threaded hole is provided on the surface of the first movable plate, and an insertion rod is provided with a thread in the threaded hole, the insertion rod cooperates with the through hole and the socket, and the two adjacent insertion rods inside the cavity are staggered, and the two sockets are staggered.

[0010] The second connecting member includes a second fixing rod, which is fixed between the fixing block and the inner wall of the cavity. A second movable plate is movably sleeved on the second fixing rod. A wedge block is fixed to one end of the second movable plate. The inclined structure at one end of the fixing plate cooperates with the inclined surface of the wedge block. A second spring is connected between the second movable plate and the inner wall of the cavity. The second spring is sleeved on the outside of the second fixing rod.

[0011] A groove is provided on the inner wall of the cavity near the second fixing rod, the wedge-shaped block cooperates with the groove, a through groove is provided on the inner wall of the groove, the through groove passes through the curtain wall body, two positioning grooves are provided on the inner wall of the cavity away from the groove, the positioning groove passes through the outer surface of the curtain wall body, a positioning block is fixed on the side of the wedge-shaped block near the groove, and the positioning block cooperates with the through groove and the positioning groove.

[0012] A plurality of guide grooves are provided on both sides of the inner wall of the cavity, and the guide grooves penetrate the inner wall of the movable groove. A guide block is slidably arranged inside the guide groove, and the guide block is fixedly connected to the extrusion block. A return spring is connected between the inner side of the guide block and the inner wall of the guide groove.

[0013] The threaded holes on the two movable blocks have opposite thread directions. A guide rod is provided on one side of the screw rod. The guide rod is fixed inside the cavity and passes through the movable block. The movable block and the guide rod are slidably matched.

[0014] The first fixing rod has one end away from the fixing block to fix the limiting block, a circular groove is provided on one side of the curtain wall body, a knob is rotatably provided inside the circular groove, the inner end of the knob is connected to the first bevel gear, and the outer end of the knob is provided with a cross groove.

[0015] The present invention has the following beneficial effects:

[0016] The present invention facilitates the screw rod to rotate through the meshing action of the first bevel gear and the second bevel gear. Under the thread cooperation of the movable block and the screw rod, the two movable blocks are adjusted to be close to each other. Under the hinge action of the two ends of the connecting arm, the extrusion block is further extruded outward until the extrusion block passes through the movable groove and is inserted into the cavity of the horizontally adjacent curtain wall bodies, thereby realizing the preliminary connection and fixation of the two horizontally adjacent curtain wall bodies.

[0017] The extrusion block and the extrusion head cooperate with each other. As the extrusion block moves, it is convenient to squeeze the extrusion head in the direction close to the fixed block, driving the first movable plate to compress the first spring along the direction of the first fixed rod, and at the same time driving the insertion rod to pass through the through hole and insert into the insertion holes on the vertically adjacent curtain wall bodies, thereby realizing the splicing and fixing of two vertically adjacent curtain wall bodies. The staggered arrangement of the two adjacent insertion rods and the staggered arrangement of the two insertion holes ensure that the two insertion rods in the same cavity can be smoothly inserted into the two vertically adjacent curtain wall bodies.

[0018] At the same time, the inclined structure at one end of the fixed plate cooperates with the inclined surface of the wedge block, so that during the extrusion process of the extrusion head, the wedge block is squeezed into the groove, thereby driving the positioning block to pass through the through groove and insert into the positioning groove on the horizontally adjacent curtain wall bodies, further ensuring the stability of the splicing of two horizontally adjacent curtain wall bodies, effectively reducing the use of bolts, facilitating the installation of building curtain walls, and improving the installation efficiency of building curtain walls. It solves the problem that traditional curtain walls are set separately, and when laying the building curtain walls, a large number of bolts are needed to connect and fix the adjacent curtain walls, and the curtain walls cannot be spliced ​​and fixed by the curtain walls themselves, resulting in the installation of the building curtain walls. The installation requires a large number of bolts to be tightened, the operation is cumbersome, the labor intensity is high, and the efficiency is low.

[0019] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 A top view of the present invention;

[0023] Figure 3 for Figure 2 Structural diagram of the middle section AA;

[0024] Figure 4 for Figure 3 Schematic diagram of the structure of the middle section BB;

[0025] Figure 5 for Figure 3 Schematic diagram of the enlarged structure at C in the middle;

[0026] Figure 6 for Figure 3 Schematic diagram of the enlarged structure at D in the middle;

[0027] Figure 7 for Figure 4 Schematic diagram of the enlarged structure at E in the middle;

[0028] Figure 8 It is a structural schematic diagram of the splicing state of the curtain wall in the present invention;

[0029] Fig. 9 for Figure 8 An internal cross-sectional view of

[0030] Fig.10 for Fig. 9 The enlarged structural diagram at F in the middle;

[0031] Fig.11 for Fig. 9 Schematic diagram of the enlarged structure at G in the middle;

[0032] Fig.12 for Fig. 9 Schematic diagram of the enlarged structure at H in the middle.

[0033] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0034] 1. Curtain wall body; 2. Cavity; 3. Screw rod; 4. Movable block; 5. Extrusion block; 6. Connecting arm; 7. First bevel gear; 8. Second bevel gear; 9. Fixed block; 10. First fixed rod; 11. First movable plate; 12. First spring; 13. Fixed plate; 14. Extrusion head; 15. Insert rod; 16. Socket; 17. Second fixed rod; 18. Wedge block; 19. Second movable plate; 20. Second spring; 21. Groove; 22. Positioning block; 23. Positioning groove; 24. Guide groove; 25. Guide block; 26. Reset spring; 27. Guide rod; 28. Limit block; 29. ​​Knob. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] In the description of the present invention, it should be understood that the terms "upper", "middle", "outer", "inner" and the like indicating directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the components or elements referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0037] See also Figure 1-Figure 12 As shown, the present invention is a modular building curtain wall, including a curtain wall body 1, a cavity 2 is opened inside the curtain wall body 1, a screw rod 3 is arranged inside the cavity 2, two movable blocks 4 are threadedly arranged on the screw rod 3, two movable grooves are penetrated through the inner wall of the cavity 2, an extrusion block 5 is movably arranged on one side of the cavity 2, and is matched with the movable groove, a connecting arm 6 is hinged between the extrusion block 5 and the movable block 4, two fixed blocks 9 are relatively fixed on one side of the cavity 2 away from the extrusion block 5, and a first connecting member and a second connecting member are arranged on the fixed block 9;

[0038] A second bevel gear 8 is disposed on one side of the outer wall of the screw rod 3 , and a first bevel gear 7 is meshed with the rear side of the second bevel gear 8 .

[0039] Through the meshing action of the first bevel gear 7 and the second bevel gear 8, the screw rod 3 is driven to rotate. Under the thread cooperation of the movable block 4 and the screw rod 3, the two movable blocks 4 are adjusted to be close to each other. Under the hinge action of the two ends of the connecting arm 6, the extrusion block 5 is extruded outward until the extrusion block 5 passes through the movable groove and is inserted into the cavity 2 of the adjacent curtain wall bodies 1 in the horizontal direction, thereby realizing the preliminary connection and fixation of the two adjacent curtain wall bodies 1 in the horizontal direction.

[0040] The first connecting member includes a first fixing rod 10, which is fixedly connected to the fixing block 9. A first movable plate 11 is movably sleeved on the first fixing rod 10. A first spring 12 is connected between the first movable plate 11 and the fixing block 9. The first spring 12 is sleeved on the outside of the first fixing rod 10. A fixing plate 13 is fixed to one end of the first movable plate 11 close to the inner wall of the cavity 2. An extrusion head 14 is fixed to one end of the fixing plate 13 close to the through groove. The extrusion head 14 cooperates with the extrusion block 5. The end of the fixing plate 13 away from the extrusion head 14 is an inclined structure. The ends of the extrusion head 14 and the extrusion block 5 close to each other are both arc structures. A through hole and a socket 16 are provided on the side of the surface of the curtain wall body 1 close to the fixing block 9. A threaded hole is provided on the surface of the first movable plate 11. A plug rod 15 is provided with a thread in the threaded hole. The plug rod 15 cooperates with the through hole and the socket 16, and two adjacent plug rods 15 in the cavity 1 are staggered, and the two sockets 16 are staggered.

[0041] In the above structure, through the mutual cooperation between the extrusion block 5 and the extrusion head 14, as the extrusion block 5 moves, it is convenient to squeeze the extrusion head 14 in the direction close to the fixed block 9, driving the first movable plate 11 to compress the first spring 12 along the direction of the first fixed rod 10, and at the same time driving the insertion rod 15 to pass through the through hole and insert into the insertion hole 16 on the vertically adjacent curtain wall body 1, thereby realizing the splicing and fixation of the two adjacent curtain wall bodies 1 in the vertical direction. The staggered arrangement of the two adjacent insertion rods 15 and the staggered arrangement of the two insertion holes 16 ensure that the two insertion rods 15 in the same cavity 2 can be smoothly inserted into the two adjacent curtain wall bodies 1 in the vertical direction.

[0042] The second connecting member includes a second fixing rod 17, which is fixed between the fixing block 9 and the inner wall of the cavity 2. A second movable plate 19 is movably sleeved on the second fixing rod 17. A wedge block 18 is fixed at one end of the second movable plate 19. The inclined structure at one end of the fixing plate 13 cooperates with the inclined surface of the wedge block 18. A second spring 20 is connected between the second movable plate 19 and the inner wall of the cavity 2. The second spring 20 is sleeved on the outer side of the second fixing rod 17. A groove 21 is provided on the side of the inner wall of the cavity 2 close to the second fixing rod 17. The wedge block 18 cooperates with the groove 21. A through groove is provided on the inner wall of the groove 21. The through groove passes through the curtain wall body 1. Two positioning grooves 23 are provided on the side of the inner wall of the cavity 2 away from the groove 21. The positioning groove 23 passes through the outer surface of the curtain wall body 1. A positioning block 22 is fixed on the side of the wedge block 18 close to the groove 21. The positioning block 22 cooperates with the through groove and the positioning groove 23.

[0043] By cooperating with the inclined structure at one end of the fixing plate 13 and the inclined surface of the wedge block 18, it is convenient to squeeze the wedge block 18 into the groove 21 during the extrusion of the extrusion head 14, thereby driving the positioning block 22 to pass through the through groove and be inserted into the positioning groove 23 on the horizontally adjacent curtain wall bodies 1, thereby further ensuring the stability of the splicing of the two horizontally adjacent curtain wall bodies 1.

[0044] A plurality of guide grooves 24 are provided on both sides of the inner wall of the cavity 2. The guide grooves 24 penetrate the inner wall of the movable groove. A guide block 25 is slidably arranged inside the guide groove 24. The guide block 25 is fixedly connected to the extrusion block 5, which effectively limits and guides the extrusion block 5. A return spring 26 is connected between the inner side of the guide block 25 and the inner wall of the guide groove 24, so as to facilitate the extrusion block 5 to return to its initial position when the curtain wall is disassembled.

[0045] The threaded directions of the threaded holes on the two movable blocks 4 are opposite. A guide rod 27 is provided on one side of the screw rod 3. The guide rod 27 is fixed inside the cavity 2. The guide rod 27 passes through the movable block 4. The movable block 4 slides with the guide rod 27, which effectively limits and guides the movable block 4, thereby ensuring the stability of the movable block 4 during the movement along the screw rod 3.

[0046] The first fixing rod 10 has one end away from the fixing block 9 to fix a limit block 28. A circular groove is provided on one side of the curtain wall body 1. A knob 29 is rotatably provided inside the circular groove. The inner end of the knob 29 is connected to the first bevel gear 7. The outer end of the knob 29 has a cross groove.

[0047] Example:

[0048] When laying the curtain wall, firstly, the adjacent curtain wall bodies 1 are butted together, and the curtain wall bodies 1 are supported by external equipment, and then, under the action of the cross groove on the knob 29, the knob 29 is adjusted to rotate, driving the first bevel gear 7 to rotate, and under the meshing action of the first bevel gear 7 and the second bevel gear 8, the screw rod 3 is driven to rotate, and combined with the threaded cooperation between the movable block 4 and the screw rod 3, and the sliding cooperation between the movable block 4 and the guide rod 27, the two movable blocks 4 are driven to stably approach each other;

[0049] Under the hinged action at both ends of the connecting arm 6, combined with the sliding cooperation between the guide block 25 and the guide groove 24, the extrusion block 5 is pushed outward, and the return spring 26 is stretched at the same time. As the two movable blocks 4 approach each other, the extrusion block 5 is driven to pass through the movable groove and move to the cavity 2 of the curtain wall body 1 adjacent in the horizontal direction, so that the two curtain wall bodies 1 adjacent in the horizontal direction are preliminarily plugged together;

[0050] As the extrusion block 5 continues to move, the two extrusion heads 14 in the inner cavity 2 of the adjacent curtain wall bodies 1 are squeezed toward both sides, driving the first movable plate 11 to compress the first spring 12 along the direction of the first fixing rod 10, and at the same time driving the insertion rod 15 to pass through the through hole and insert into the insertion hole 16 on the vertically adjacent curtain wall bodies 1, thereby realizing the splicing and fixing of the two vertically adjacent curtain wall bodies 1;

[0051] As the extrusion head 14 is extruded, the inclined structure at one end of the fixed plate 13 cooperates with the inclined surface of the wedge block 18, and during the extrusion process of the extrusion head 14, the wedge block 18 is extruded into the groove 21, and at the same time, the second movable plate 19 is driven to compress the second spring 20 along the direction of the second fixed rod 17, until the positioning block 22 is driven to pass through the through groove and inserted into the positioning groove 23 on the adjacent curtain wall bodies 1 in the horizontal direction, so that the two adjacent curtain wall bodies 1 in the horizontal direction are further spliced ​​together;

[0052] The use of bolts is effectively reduced. With the help of the curtain wall body 1 itself, the splicing and fixing of adjacent building curtain walls is realized, which facilitates the rapid splicing and installation of the building curtain walls, effectively improves the installation efficiency of the building curtain walls, and solves the problem that the traditional curtain walls are set separately. When laying the building curtain walls, a large number of bolts are needed to connect and fix the adjacent curtain walls, and the curtain walls cannot be spliced ​​and fixed by the curtain walls themselves, resulting in the installation of the building curtain walls. A large number of bolts need to be tightened, the operation is relatively cumbersome, the labor intensity is high, and the efficiency is low;

[0053] The threaded connection between the plug rod 15 and the threaded hole facilitates the flexible disassembly of the plug rod 15. Fig.10 As shown, during the installation of the building curtain wall, the insertion rod 15 inside the uppermost or lowermost curtain wall body 1 is prevented from extending to the outside, thereby affecting the installation of the building curtain wall;

[0054] The elastic action of the first spring 12, the second spring 20 and the return spring 26 facilitates the corresponding extrusion head 14, the wedge block 18 and the extrusion block 5 to return to the initial state when the curtain wall body 1 is disassembled, thereby facilitating the rapid disassembly of the building curtain wall.

[0055] It should be further explained that the installation structure, connection method or setting method of each component in the present invention are all common mechanical methods, and they can be implemented as long as they can achieve their beneficial effects.

[0056] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0057] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A modular building curtain wall, comprising a curtain wall body (1), characterized in that: A cavity (2) is provided inside the curtain wall body (1), a screw rod (3) is provided inside the cavity (2), two movable blocks (4) are threadedly provided on the screw rod (3), two movable grooves are penetrated through the inner wall of the cavity (2), an extrusion block (5) is movably provided on one side of the cavity (2) and cooperates with the movable groove, a connecting arm (6) is hinged between the extrusion block (5) and the movable block (4), two fixed blocks (9) are relatively fixed on the side of the cavity (2) away from the extrusion block (5), and a first connecting member and a second connecting member are provided on the fixed block (9); A second bevel gear (8) is provided on one side of the outer wall of the screw rod (3), and the first bevel gear (7) is meshed with the rear side of the second bevel gear (8).

2. A modular building curtain wall according to claim 1, characterized in that: The first connecting member comprises a first fixing rod (10), the first fixing rod (10) is fixedly connected to a fixing block (9), a first movable plate (11) is movably sleeved on the first fixing rod (10), a first spring (12) is connected between the first movable plate (11) and the fixing block (9), the first spring (12) is sleeved on the outside of the first fixing rod (10), a fixing plate (13) is fixed to one end of the first movable plate (11) close to the inner wall of the cavity (2), an extrusion head (14) is fixed to one end of the fixing plate (13) close to the through groove, the extrusion head (14) and the extrusion block (5) cooperate with each other, and the end of the fixing plate (13) away from the extrusion head (14) is an inclined structure.

3. A combined building curtain wall according to claim 2, characterized in that: The ends of the extrusion head (14) and the extrusion block (5) that are close to each other are both arc-shaped structures. A through hole and a plug hole (16) are provided on the surface of the curtain wall body (1) close to the fixed block (9). A threaded hole is provided on the surface of the first movable plate (11). An insertion rod (15) is provided in the threaded inner thread of the threaded hole. The insertion rod (15) cooperates with the through hole and the plug hole (16). Two adjacent insertion rods (15) in the cavity (1) are staggered, and the two plug holes (16) are staggered.

4. The combined building curtain wall according to claim 3, characterized in that: The second connecting member comprises a second fixing rod (17), the second fixing rod (17) being fixed between the fixing block (9) and the inner wall of the cavity (2), a second movable plate (19) being movably sleeved on the second fixing rod (17), a wedge block (18) being fixed to one end of the second movable plate (19), an inclined structure at one end of the fixing plate (13) being matched with an inclined surface of the wedge block (18), a second spring (20) being connected between the second movable plate (19) and the inner wall of the cavity (2), and the second spring (20) being sleeved on the outside of the second fixing rod (17).

5. The combined building curtain wall according to claim 4, characterized in that: A groove (21) is provided on the inner wall of the cavity (2) on a side close to the second fixing rod (17), the wedge block (18) cooperates with the groove (21), a through groove is provided on the inner wall of the groove (21), the through groove passes through the curtain wall body (1), two positioning grooves (23) are provided on the inner wall of the cavity (2) on a side away from the groove (21), the positioning grooves (23) pass through the outer surface of the curtain wall body (1), a positioning block (22) is fixed on a side of the wedge block (18) close to the groove (21), the positioning block (22) cooperates with the through groove and the positioning groove (23).

6. The combined building curtain wall according to claim 5, characterized in that: A plurality of guide grooves (24) are provided on both sides of the inner wall of the cavity (2), the guide grooves (24) penetrate the inner wall of the movable groove, a guide block (25) is slidably arranged inside the guide groove (24), the guide block (25) is fixedly connected to the extrusion block (5), and a return spring (26) is connected between the inner side of the guide block (25) and the inner wall of the guide groove (24).

7. The combined building curtain wall according to claim 6, characterized in that: The threaded holes on the two movable blocks (4) have opposite thread directions. A guide rod (27) is provided on one side of the screw rod (3). The guide rod (27) is fixed inside the cavity (2). The guide rod (27) passes through the movable block (4). The movable block (4) is slidably matched with the guide rod (27).

8. The combined building curtain wall according to claim 7, characterized in that: A limiting block (28) is fixed to one end of the first fixing rod (10) away from the fixing block (9); a circular groove is provided on one side of the curtain wall body (1); a knob (29) is rotatably arranged inside the circular groove; an inner end of the knob (29) is connected to the first bevel gear (7); and an outer end of the knob (29) is provided with a cross groove.

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