Mounting device for a snowplow head

Abstract

Fastening device for a snowplow head, characterized in that it comprises the following: a snow removal section (100); a hinge section (200) which serves for the rotatable insertion of the snow removal section (100) with the snow removal head and which comprises a fastening ring (201) and a tailstock (202), wherein the fastening ring (201) is fixedly provided at the bottom with a football goal-shaped frame (203), the tailstock (202) is fixedly provided at one end with a removable plug-in mechanism (204), and the football goal-shaped frame (203) is provided with a steering swivel mechanism (205) which is rotatably connected to the removable plug-in mechanism (204); a lock actuation section (300) which is arranged on the hinge section (200) and which serves to realize a self-locking mechanism with simultaneous rotation.

Description

TECHNICAL FIELD

[0001] The present invention relates to the technical field of a hand-held snow remover and, more particularly, to a mounting device for a snow remover head. STATE OF THE ART

[0002] The hand-held snow blower is mainly used during heavy snowfall to clear the snow cover that obstructs traffic.

[0003] The hand-held snow sweeper consists of a hand-held motorcycle and a snow wheel roller connected by rotors, and by turning an operating lever, an angle change of the snow wheel roller is realized in order to facilitate snow clearing in corners;

[0004] Currently, the rotors used between the two have the following disadvantages: 1. Both ends of the rotor are respectively fixed to the snow wheel roller and the hand-held motorcycle by several sets of bolts, which means a complete disassembly during long-term transportation or disassembly during maintenance that requires disassembly, which causes inconvenience; 2. The rotor is steered by the operating lever, but has no self-locking function, and incorrect swinging is easy to occur when clearing snow after steering, and therefore cooperative operation of two people is required, which increases labor costs. CONTENTS OF THE PRESENT UTILITY MODEL

[0005] In view of the above-described problems of the conventional snow removal head attachment device, the present invention is provided.

[0006] The object of the present invention is therefore to provide a fastening device for a snow clearing head.

[0007] In order to solve the above-mentioned technical problems, the present invention provides the following technical solutions, namely a fastening device for a snow removal head, comprising: a snow clearing section; a hinge portion for rotatably inserting the snow removal portion with the snow removal head, comprising a mounting ring and a tailstock, the mounting ring being fixedly provided with a soccer goal-shaped frame at the bottom, the tailstock being fixedly provided with a detachable plug-in mechanism at one end, and the soccer goal-shaped frame being provided with a steering rotation mechanism rotatably connected to the detachable plug-in mechanism; a lock actuating section which is arranged on the hinge section and which serves to realize self-locking with simultaneous rotation.

[0008] As a preferred solution of the fastening device for a snow plow head according to the invention, the steering rotation mechanism comprises a rotation axis rotatably connected to the inside of the soccer goal-shaped frame and a gear wheel fixed to the inner tip of the soccer goal-shaped frame, wherein the outside of the rotation axis is firmly covered with a gear wheel segment.

[0009] As a preferred solution of the fastening device according to the invention for a snow plow head, the removable plug-in mechanism comprises a plug-in component one, one end of which is rotatably connected to the rotation axis, and a plug-in component two, which is fixedly arranged on the side of the tailstock.

[0010] As a preferred solution of the fastening device for a snow plow head according to the invention, the male component two has a structure identical to the male component one, comprising a housing in which a cavity is arranged and which is provided on one side with a plug and on one side with a socket connected to the cavity, wherein the cavity is provided with an arcuate plate connected to one end of the plug and fixedly with a limiting plate, wherein the arcuate plate is rotatably provided with a semicircular block connected under tension by an elastic element.

[0011] As a preferred solution of the fastening device for a snow plow head according to the invention, the elastic element comprises a guy stand fixed to the outer circumference of the semicircular block, a roller rotatably connected to the other end of the guy stand, and an arcuate holder fixed in the cavity.

[0012] As a preferred solution of the fastening device for a snow plow head according to the invention, a fastening holder is fastened to the outer circumference of the arc-shaped holder, the other end of which is rotatably connected to a pulley, wherein the fastening holder is firmly connected to a spring one on one side and a tensioning cable is fastened to the other end of the spring one.

[0013] As a preferred solution of the fastening device for a snow plow head according to the invention, the lock actuating section comprises an actuating lever which is rotatably connected to the football goal-shaped frame by tensioning through the tension holder and whose lower end is engaged with the upper end of the rotation axis by a coupling.

[0014] As a preferred solution of the fastening device for a snow plow head according to the invention, a limit lever, the low end of which is inserted into a limit hole, is fastened below the operating lever, wherein there are several limit holes distributed in an annular arrangement on the surface of the football goal-shaped frame.

[0015] As a preferred solution of the fastening device for a snow removal head according to the invention, the tension holder comprises a base which is fixed to the surface of the soccer goal-shaped frame and a bearing which is covered on the outer side of the operating lever, wherein a connecting lever is fixed to the outer circumference of the bearing, the connecting lever is rotatably connected to the base and a spring two is fixed to the bottom of the connecting lever which is fixedly connected to the surface of the soccer goal-shaped frame.

[0016] As a preferred solution of the fastening device for a snow removal head according to the invention, the coupling comprises an insertion hole arranged at the upper end of the rotation axis and an insertion column which is inserted into the insertion hole, wherein connecting holders are respectively fastened to the upper end of the insertion column and to the lower end of the actuating lever and the two connecting holders are rotatably connected to one another by a movable lever.

[0017] The present invention has the following advantageous effects. By providing a lock operating portion, the operating lever has a self-locking function during steering operation, which solves the problem of requiring a driver during operation of the conventional snow sweeper, and the entire operation requires only one person, thus reducing labor costs and improving work efficiency.

[0018] The detachable plug-in mechanism facilitates the separation between the snow removal head and the snow washing roller, has the effects of simple structure, stable connection and easy operation, and reduces the difficulty of disassembled transportation over long distances and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] To better illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments are briefly described below. It is understood that the drawings in the following description represent only some embodiments of the present invention and that those skilled in the art can derive other drawings from these drawings without inventive effort. In these drawings: Fig. 1 is a schematic overall structural view of the snow removal head attachment device according to the present invention. Fig. 2 is a schematic structural view of the snow removing portion of the snow remover head attachment device according to the present invention. Fig. 3 is a schematic structural view of the hinge portion of the snow removal head attachment device according to the present invention. Fig. 4 is a schematic structural view of the lock operating portion of the snow removal head attachment device according to the present invention. Fig. Figure 5 is an enlarged schematic structural view of section A of Fig. 4 according to the present invention. Fig. 6 is a schematic structural view of the detachable plug-in mechanism of the snow removal head attachment device according to the present invention. Fig. 7 is a schematic structural view of the male component two of the snow removal head attachment device according to the present invention. Fig. 8 is a schematic structural view after plugging in the plug-in component one and the plug-in component two of the snow removal head attachment device according to the present invention. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0021] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention; however, the present invention may be practiced otherwise than as described herein, and one skilled in the art may similarly practice the present invention without departing from the spirit and scope of the present invention; therefore, the present invention is not limited to the specific embodiments disclosed below.

[0022] Furthermore, the terms "one embodiment" or "one embodiment" or "one embodiments" refer to a particular feature, structure, or characteristic that may be included in at least one implementation of the present invention. The appearances of "in one embodiment" in various places throughout the specification do not always refer to the same embodiment, nor do they refer to the embodiment that separately or alternatively dismisses other embodiments.

[0023] Next, the present invention will be described in detail with reference to the schematic drawings. For convenience of explanation, in the detailed description of the embodiments of the invention, the cross-sectional view illustrating the structure of the device is not partially enlarged to a general scale, and the schematic drawings merely represent examples that are not intended to limit the scope of the present invention. Furthermore, the three-dimensional spatial dimensions of length, width, and depth should be included in the actual manufacturing process. Example 1

[0024] With reference to Fig. 1 is provided a schematic overall structural view of the attachment device for a snow removal head as shown in Fig. 1 to 5, the fastening device for a snow removal head comprises: a snow clearing section 100; In particular, the snow removal section 100 comprises a skirt 101, the inside of which is rotatably connected to a cleaning roller 102, and on the outside of which auxiliary wheels 103 are arranged at both end positions, and on which a snow removal motor is arranged, which drives the cleaning roller 102 to rotate and clear the snow; a hinge portion 200 for rotatably inserting the snow removal portion 100 with the snow removal head, comprising a mounting ring 201 and a tailstock 202, wherein the mounting ring 201 is fixedly provided with a soccer goal-shaped frame 203 at the bottom, the tailstock 202 is fixedly provided with a detachable plug-in mechanism 204 at one end, and the soccer goal-shaped frame 203 is provided with a steering rotation mechanism 205 rotatably connected to the detachable plug-in mechanism 204; a lock actuating portion 300 which is arranged on the hinge portion 200 and which serves to realize self-locking with simultaneous rotation.

[0025] Furthermore, the steering rotation mechanism 205 comprises a rotation axis 205a rotatably connected to the inside of the soccer goal-shaped frame 203 and a gear 205b fixed to the inner tip of the soccer goal-shaped frame 203, wherein the outside of the rotation axis 205a is fixedly covered with a gear segment 205c.

[0026] Specifically, the rotation shaft 205a is rotatable with the inside of the soccer goal-shaped frame 203, and its upper end is disposed through the upper surface of the soccer goal-shaped frame 203. When the upper end of the rotation shaft 205a is rotated, the gear segment 205c rotates synchronously. Since the gear segment 205c is engaged with the gear 205b, the gear 205b is driven to rotate. The gear 205b is fixed to the inner tip of the soccer goal-shaped frame 203. Therefore, when the gear 205b is rotated, the soccer goal-shaped frame 203 is forcibly rotated, thereby realizing a steering operation of the snow removal section 100.

[0027] Furthermore, the lock operating section 300 comprises an operating lever 301 which is rotatably connected to the soccer goal-shaped frame 203 by tensioning through the tension holder 302 and whose lower end is engaged with the upper end of the rotation axis 205a through a coupling 303.

[0028] Furthermore, a limit lever 304, the low end of which is inserted into a limit hole 305, is attached below the operating lever 301.

[0029] Specifically, the restriction hole 305 has a short bar-shaped structure, and there are a plurality of restriction holes 305 distributed in an annular array on the surface of the soccer goal-shaped frame 203, and the width of the restriction hole 305 corresponds to the diameter of the restriction lever 304, so that a pivotal movement of the restriction lever 304 can be restricted, and when the operation lever 301 is lifted, the removal of the restriction lever 304 from the restriction hole 305 is not disturbed.

[0030] Further, the tension holder 302 includes a base 302a fixed to the surface of the soccer goal-shaped frame 203, and a bearing 302b sheathed on the outer side of the operating lever 301, wherein a connecting lever 302c is fixed to the outer periphery of the bearing 302b, the connecting lever 302c is rotatably connected to the base 302a, and a spring 302d is fixed to the bottom of the connecting lever 302c, which is fixedly connected to the surface of the soccer goal-shaped frame 203.

[0031] In particular, the inner periphery of the bearing 302b is tightly wrapped with the operating lever 301, so that the operating lever 301 can still be rotated while the outer periphery of the bearing 302b is fixed;

[0032] Furthermore, the coupling 303 comprises an insertion hole 303a arranged at the upper end of the rotation axis 205a, and an insertion column 303b inserted into the insertion hole 303a, wherein connecting holders 303c are respectively fixed to the upper end of the insertion column 303b and to the lower end of the operating lever 301, and the two connecting holders 303c are rotatably connected to each other by a movable lever 303d.

[0033] In particular, both the insertion column 303b and the insertion hole 303a are hexagonal, and therefore the rotation axis 205a can be rotated when the operating lever 301 is pivoted.

[0034] Operation procedure: When the angle is to be adjusted, the hand-operated end of the operating lever 301 is lifted by hand, and when the hand-operated end of the operating lever 301 is lifted, it will rotate around the pivot point of the tension holder 302d and the connecting lever 302c as the support point, and during the rotation, the two spring 302d is tensioned, and when the operating lever 301 is lifted, the insertion column 303b is slightly pulled out from the insertion hole 303a by the rotatable insertion of the movable lever 303d, not completely pulled out, at the same time, the limit lever 304 is removed from the limit hole 305, and then the rotation of the operating lever 301 is performed depending on the desired direction;

[0035] The rotation of the operating lever 301 drives the rotation shaft 205a to rotate, and when the upper end of the rotation shaft 205a is rotated, the gear segment 205c rotates synchronously, and since the gear segment 205c is engaged with the gear 205b, the gear 205b is driven to rotate. The gear 205b is fixed to the inner tip of the soccer goal-shaped frame 203, therefore, the soccer goal-shaped frame 203 is forcibly rotated when the gear 205b is rotated, thereby realizing a steering operation of the snow removal section 100;

[0036] When the angle is appropriately adjusted, the operating lever 301 is slightly released, and the operating lever 301 moves downward by the reaction force of the two springs 302d until the limit lever 304 is inserted into the limit hole 305. At this time, the limit lever 304 limits the swing direction of the operating lever 301. Therefore, the self-locking effect is achieved, which solves the problem that a handlebar is required for the work of the conventional snow sweeper, and the entire work needs only one person, which reduces labor costs and improves work efficiency. Example 2

[0037] With reference to Fig. 6 to 7, this embodiment differs from the first embodiment in that the removable plug-in mechanism 204 comprises a plug-in component one 204a, one end of which is rotatably connected to the rotation axis 205a, and a plug-in component two 204b, which is fixedly arranged on the side of the tailstock 202.

[0038] Furthermore, the plug component two 204b has a structure identical to the plug component one 204a, comprising a housing 204b-1 in which a cavity 204b-2 is arranged and which is provided on one side with a plug 204b-3 and on one side with a socket 204b-4 connected to the cavity 204b-2, wherein the cavity 204b-2 is provided with an arcuate plate 204b-5 connected to one end of the plug 204b-3 and fixedly with a limiting plate 204b-6, wherein the arcuate plate 204b-5 is rotatably provided with a semicircular block 204b-7 connected under tension by an elastic element.

[0039] In particular, the plug-in component one 204a differs from the plug-in component two 204b in that a disk is attached to one end of the housing 204b-1, in which a through hole for encasing with the rotation axis 205a is arranged.

[0040] Specifically, the limit plate 204b-6 is at the same height as one end of the arcuate plate 204b-5, and the elastic member naturally pulls the semicircular block 204b-7 to rotate within the arcuate plate 204b-5 so that the angle between the horizontal portion of the semicircular block 204b-7 and the horizontal direction of the limit plate 204b-6 is 25° and the horizontal inclined surface of the semicircular block 204b-7 faces the bushing 204b-4 side;

[0041] During insertion, the plugs 204b-3 of the plug-in component one 204a and the plug-in component two 204b are respectively inserted into the sockets 204b-4. When the triangular inclined surfaces of the plugs 204b-3 abut against the semicircular blocks 204b-7, the two semicircular blocks 204b-7 stretch the elastic element. When the plugs 204b-3 are inserted, the horizontal portion of the semicircular blocks 204b-7 gradually aligns with the horizontal direction of the limiting plate 204b-6. The two arcuate plates 204b-5 enclose a circular cavity, and the two semicircular blocks 204b-7 are completely joined together to form a disk in the circular cavity, which are arranged in the circular cavity without restriction. Therefore, the elastic element, under their reaction force, drives the two semicircular blocks 204b-7 to rotate again.and since the separation direction of the two disc blocks 204b-7 is opposite to the separation direction of the plug-in component one 204a and the plug-in component two 204b, therefore a connection security is achieved.

[0042] The remaining constructions are the same as in Example 1.

[0043] Operational sequence: During insertion, the plugs 204b-3 of the plug-in component one 204a and the plug-in component two 204b are respectively inserted into the sockets 204b-4, and when the triangular inclined surfaces of the plugs 204b-3 abut against the semicircular blocks 204b-7, the two semicircular blocks 204b-7 stretch the elastic member, and when the plugs 204b-3 are inserted, the horizontal section of the semicircular blocks 204b-7 gradually align with the horizontal direction of the limiting plate 204b-6, and then the two arc-shaped plates 204b-5 enclose a circular cavity, and the two semicircular blocks 204b-7 are completely joined into a disk in the circular cavity, which are arranged in the circular cavity without restriction, therefore, the elastic element drives the two semicircular blocks 204b-7 to rotate again under their reaction force. on (as in Fig. 8), and since the separation direction of the two disk blocks 204b-7 is opposite to the separation direction of the plug component one 204a and the plug component two 204b, therefore a connection security is achieved. Example 3

[0044] With reference to Fig. 7, this embodiment differs from the above embodiments in that the elastic member includes a guy stand 204b-8 fixed to the outer periphery of the semicircular block 204b-7, a pulley 204b-9 rotatably connected to the other end of the guy stand 204b-8, and an arcuate holder 204b-10 fixed in the cavity 204b-2.

[0045] Further, a fixing bracket 204b-11 is fixed to the outer periphery of the arcuate bracket 204b-10, the other end of which is rotatably connected to a pulley 204b-12, the fixing bracket 204b-11 being fixedly connected to a spring one 204b-13 on one side, and a tension cable 204b-14 being fixed to the other end of the spring one 204b-13.

[0046] Specifically, the outer side of the guy stand 204b-8 is rotatably connected to a rotating column, the rope pulley 204b-12 is arranged by a bearing foot at one end of the arc-shaped holder 204b-10, a limiting bar is arranged on the bearing foot, which is arranged on the outer side of the pulley 204b-9, and the other end of the tensioning cable 204b-15 is fixed to the rotating column around the pulley 204b-12, while the limiting bar serves to limit the tensioning cable 204b-15 to prevent it from jumping off.

[0047] Specifically, the outer side of the casing 204b-1 is provided with an arcuate bowl whose arcuate direction corresponds to the arcuate movement path of the guy stand 204b-8, and in which a release lever 204c is arranged. The other end of the release lever 204c is fixedly connected to the guy stand 204b-8. By pulling the release lever 204c, the guy stand 204b-8 is forcibly driven to rotate. Therefore, the two semicircular blocks 204b-7 are forcibly rotated until their separation direction corresponds to the separation direction of the plug-in component one 204a and the plug-in component two 204b. At this point, separation of the plug-in component one 204a from the plug-in component two 204b is achieved, and disassembly is completed.

[0048] The remaining constructions are the same as in Example 2.

[0049] Operation procedure: When the semicircular blocks 204b-7 are rotated under the force, the guy stand 204b-8 has a micro-arc structure, therefore, the rollers 204b-9 at its ends roll against the inside of the arc-shaped holder 204b-10 when it rotates under the force, and with the change of the angle of the guy stand 204b-8, the spring 204b-13 is pulled by the tension cable 204b-15, and when the two semicircular blocks 204b-7 are completely brought together, the two semicircular blocks 204b-7 are driven to rotate again under the reaction force of the spring one 204b-13 and a locked configuration is formed.

[0050] It is important to note that the construction and arrangement of the present invention shown in the various exemplary embodiments are only exemplary. Although only a few embodiments have been described in detail in this disclosure, it should be readily understood by those skilled in the art who read this disclosure that many modifications are possible (e.g., size, dimensions, structures, shapes and proportions, values ​​of parameters (e.g., temperature, pressure, etc.), arrangement, use of materials, colors, changes in orientations of the various elements, etc.) without materially departing from the novel teachings and advantages of the subject matter described in this application.For example, elements shown as being integrally molded may be constructed from multiple parts or elements, the position of the elements may be reversed or otherwise altered, and the nature, number, or position of the discrete elements may be modified or changed. Accordingly, all such modifications are intended to be included within the scope of the present invention. Any procedure or order of any operations or method steps may be changed or rearranged according to alternative embodiments. Any phrase "arrangement plus function" in the claims is intended to cover the structures described in the present invention that perform the functions described herein, and not only structural equivalents, but also equivalent structures.Other substitutions, modifications, changes, and omissions may be made to the design, operation, and arrangement of the exemplary embodiments without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments, but extends to various modifications that still fall within the scope of the appended claims.

[0051] In addition, in order to provide a concise description of exemplary embodiments, not all features of the actual embodiments (i.e., those that are not relevant to the currently contemplated best mode of carrying out the present invention or that are not relevant to practicing the present invention) may be described.

[0052] It should be understood that in developing any actual embodiment, such as in any project or design program, numerous decisions regarding the specific embodiments may be made. Such a development effort can be complex and time-consuming, but for those skilled in the art having the benefit of this disclosure, it is a routine task in design, manufacturing, and fabrication that does not require undue experimentation.

[0053] It should be noted that the above embodiments are only for illustrating the technical solutions of the present invention and are not to be understood as limiting, and that although the present invention has been described in detail with reference to preferred embodiments, it should be understood by those skilled in the art that all modifications and equivalent replacements of the technical solutions of the present invention, without departing from the spirit and scope of the technical solutions of the present invention, are intended to fall within the claims of the present invention.

Claims

[1] Mounting device for a snow removal head, characterized by that it includes the following: a snow clearing section (100); a hinge section (200) for rotatably inserting the snow removal section (100) into the snow removal head, said hinge section comprising a fixing ring (201) and a tailstock (202), said fixing ring (201) being fixedly provided at the bottom with a football goal-shaped frame (203), said tailstock (202) being fixedly provided at one end with a removable plug-in mechanism (204), and said football goal-shaped frame (203) being provided with a steering rotation mechanism (205) rotatably connected to said removable plug-in mechanism (204); a lock actuating section (300) which is arranged on the hinge section (200) and which serves to realize self-locking with simultaneous rotation. [2] Fastening device for a snow removal head according to claim 1, characterized byin that the steering rotation mechanism (205) comprises a rotation axis (205a) which is rotatably connected to the inside of the football goal-shaped frame (203) and a gear (205b) which is fastened to the inner tip of the football goal-shaped frame (203), the outside of the rotation axis (205a) being firmly covered with a gear segment (205c). [3] Fastening device for a snow removal head according to claim 2, characterized by that the removable plug-in mechanism (204) comprises a plug-in component one (204a), one end of which is rotatably connected to the rotation axis (205a), and a plug-in component two (204b) which is fixedly arranged on the side of the tailstock (202). [4] Fastening device for a snow removal head according to claim 3, characterized byin that the plug-in component two (204b) has a structure identical to the plug-in component one (204a), comprising a housing (204b-1) in which a cavity (204b-2) is arranged and which is provided on one side with a plug (204b-3) and on one side with a socket (204b-4) connected to the cavity (204b-2), wherein the cavity (204b-2) is provided with an arcuate plate (204b-5) connected to one end of the plug (204b-3) and fixedly with a limiting plate (204b-6), wherein the arcuate plate (204b-5) is rotatably provided with a semicircular block (204b-7) which is connected under tension by an elastic element. [5] Fastening device for a snow removal head according to claim 4, characterized bythat the elastic element comprises a guy stand (204b-8) fixed to the outer periphery of the semicircular block (204b-7), a roller (204b-9) rotatably connected to the other end of the guy stand (204b-8), and an arcuate holder (204b-10) fixed in the cavity (204b-2). [6] Fastening device for a snow removal head according to claim 5, characterized by that a fastening holder (204b-11) is fastened to the outer circumference of the arc-shaped holder (204b-10), the other end of which is rotatably connected to a pulley (204b-12), wherein the fastening holder (204b-11) is fixedly connected on one side to a spring one (204b-13) and a tensioning cable (204b-14) is fastened to the other end of the spring one (204b-13). [7] Fastening device for a snow removal head according to claim 6, characterized bythat the lock operating section (300) comprises an operating lever (301) which is rotatably connected to the football goal-shaped frame (203) by tensioning through the tension holder (302) and whose lower end is engaged with the upper end of the rotation axis (205a) by a coupling (303). [8] Fastening device for a snow removal head according to claim 7, characterized by that a limit lever (304), the low end of which is inserted in a limit hole (305), is attached below the operating lever (301). [9] Fastening device for a snow removal head according to claim 8, characterized bythat the tension holder (302) comprises a base (302a) fixed to the surface of the football goal-shaped frame (203) and a bearing (302b) sheathed on the outside of the operating lever (301), wherein a connecting lever (302c) is fixed to the outer periphery of the bearing (302b), the connecting lever (302c) is rotatably connected to the base (302a), and a spring two (302d) is fixed to the bottom of the connecting lever (302c), which is firmly connected to the surface of the football goal-shaped frame (203). [10] Fastening device for a snow clearing head according to claim 8 or 9, characterized byin that the coupling (303) comprises an insertion hole (303a) arranged at the upper end of the rotation axis (205a), and an insertion column (303b) which is inserted into the insertion hole (303a), wherein connecting holders (303c) are respectively fastened to the upper end of the insertion column (303b) and to the lower end of the actuating lever (301), and the two connecting holders (303c) are rotatably connected to one another by a movable lever (303d).

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