Arm Joint Bushing Position Detection Tooling

Abstract

The present invention belongs to the field of boom detection, and discloses a tooling for detecting the position of arm section bushings, which comprises: a tooling platform (11) for carrying an arm section (2); a three-way positioning system disposed on the tooling platform (11) and used for positioning the arm section (2) along the length direction, width direction and height direction of the tooling platform (11) respectively; and a bushing detection system disposed on the tooling platform (11) and used for detecting the positions of a plurality of bushings (22) on the arm section (2) positioned by the three-way positioning system. The tooling for detecting the position of arm section bushings of the present invention can omit cumbersome steps such as manually pulling a steel tape measure, at least to a certain extent reduce the measurement difficulty and operation intensity of the operator, improve the measurement efficiency, and the bushing detection system is dedicated to detecting the position of arm section bushings, and its measurement reference and consistency can be effectively controlled through reasonable design, thereby improving the measurement accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of boom detection, and particularly to a tooling for detecting the position of arm joint bushings. Background Art

[0002] The boom of construction machinery such as concrete pump trucks is formed by sequentially hinging multiple arm joints end to end. Affected by factors such as material feeding, assembly accuracy, and welding deformation, the position of the bushings on the arm joints will deviate to varying degrees. Therefore, it is necessary to detect the position of the bushings on the arm joints to determine whether orthopedic correction or modification is required.

[0003] Currently, the position of arm joint bushings is mainly detected manually. However, due to the different lengths of each arm joint, which are usually relatively long, it leads to great measurement difficulty and operation intensity. Moreover, the measuring tools are affected by gravity, tension, etc., resulting in unreliable measurement accuracy. The measurement results are greatly affected by the subjective factors of the operator. In the actual production process, there are also situations of multiple adjustments and multiple measurements, which are cumbersome and time-consuming, and the efficiency is relatively low. Summary of the Invention

[0004] In view of the above-mentioned at least one defect or deficiency of the prior art, the present invention provides a tooling for detecting the position of arm joint bushings, which can reduce the measurement difficulty and operation intensity when the operator detects the position of arm joint bushings, and improve the measurement accuracy and measurement efficiency.

[0005] To achieve the above object, the present invention provides a tooling for detecting the position of arm joint bushings, which includes:

[0006] A tooling platform for carrying the arm joint;

[0007] A three-way positioning system disposed on the tooling platform and used for positioning the arm joint along the length direction, width direction, and height direction of the tooling platform respectively; and

[0008] A bushing detection system disposed on the tooling platform and used for detecting the positions of multiple bushings on the arm joint positioned by the three-way positioning system.

[0009] Optionally, the bushing detection system includes a plurality of bushing detection groups sequentially arranged at intervals along the length direction, and each bushing detection group includes:

[0010] Two movable support mechanisms, each of which is formed with a positioning hole. The two movable support mechanisms are arranged at intervals along the width direction and can both displace along the length direction and the height direction, so that the positioning holes in the two movable support mechanisms can be coaxially aligned along the width direction;

[0011] A positioning rod detachably passing through the two positioning holes coaxially aligned along the width direction; and

[0012] Two detection rings are both slidably sleeved on the positioning rod detachably.

[0013] Optionally, a plurality of circular scale marks arranged concentrically are provided on the detection ring.

[0014] Optionally, the movable support mechanism includes:

[0015] A transverse movement mechanism, including a platform guide rail extending along the length direction on the tooling platform and a transverse movement slider slidably matched with the platform guide rail;

[0016] A support seat body fixedly arranged on the transverse movement slider;

[0017] A vertical movement mechanism, including a seat body guide rail extending along the height direction on the support seat body and a vertical movement slider slidably matched with the seat body guide rail; and

[0018] A positioning plate arranged on the vertical movement slider and formed with the positioning hole.

[0019] Optionally, the transverse movement slider is formed with a transverse movement locking hole, and the transverse movement mechanism further includes a transverse movement locking connecting piece for passing through the transverse movement locking hole to be fixed with the tooling platform;

[0020] And / or, the vertical movement slider is formed with a vertical movement locking hole, and the vertical movement mechanism further includes a vertical movement locking connecting piece for passing through the vertical movement locking hole to be fixed with the support seat body.

[0021] Optionally, in at least a part of the movable support mechanism, the vertical movement slider includes a first vertical movement slider and a second vertical movement slider respectively slidably matched with the seat body guide rail, and the positioning plate includes a first positioning plate and a second positioning plate;

[0022] Wherein, the first positioning plate is fixedly connected to the first vertical movement slider, the second vertical movement slider is fixedly connected with a slider guide rail extending along the length direction, and the second positioning plate is fixedly connected with a positioning plate slider slidably matched with the slider guide rail.

[0023] Optionally, the positioning plate slider is formed with a slider locking hole, and the movable support mechanism includes a slider locking connecting piece for passing through the slider locking hole to be fixed with the slider guide rail.

[0024] Optionally, a plurality of arm joint model identification lines adjacent to the platform guide rail and arranged in sequence along the length direction are provided on the table top of the tooling platform.

[0025] Optionally, the three-way positioning system includes a lifting support mechanism for supporting the arm section, an end pushing mechanism for pushing the end of the arm section along the length direction, and a side pushing mechanism for pushing the side of the arm section along the width direction.

[0026] Optionally, the lifting support mechanism is formed as a screw-type support mechanism, and both the end pushing mechanism and the side pushing mechanism are formed as screw-type pushing mechanisms.

[0027] When detecting the position of the arm section bushing through the present invention, first place the arm section welded with the bushing on the tooling platform, position the arm section along the length direction, width direction, and height direction of the tooling platform respectively through the three-way positioning system, and then detect the positions of multiple bushings on the positioned arm section through the bushing detection system. This can eliminate cumbersome steps such as manually pulling a steel tape measure, at least reduce the measurement difficulty and operation intensity of the operator to a certain extent, improve the measurement efficiency, and the bushing detection system is dedicated to detecting the position of the arm section bushing, and its measurement reference and consistency can be effectively controlled through reasonable design, thereby improving the measurement accuracy.

[0028] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification, and are used to explain the present invention together with the following specific implementation, but do not constitute a limitation to the present invention. In the drawings:

[0030] Figure 1 is a schematic diagram of a tooling for detecting the position of the arm section bushing in a specific implementation of the present invention;

[0031] Figure 2 is for using Figure 1 in the tooling for detecting the position of the arm section bushing to detect the position of the arm section bushing;

[0032] Figure 3 is Figure 2 a partial enlarged view, in which the detection ring is concentrically aligned with the bushing hole;

[0033] Figure 4 is Figure 2 another partial enlarged view, in which the detection ring is eccentrically aligned with the bushing hole;

[0034] Figure 5 is Figure 1 a partial schematic diagram of the movable support mechanism located at the left end in

[0035] Figure 6 is Figure 5 a side view of

[0036] Figure 7 is Figure 6 the partial enlarged view A of

[0037] Figure 8 is Figure 1 another partial schematic view of the movable support mechanism located at the left end in

[0038] Figure 9 is Figure 8 the partial enlarged view B of

[0039] Explanation of reference numerals:

[0040] 1 Arm joint bushing position detection tooling

[0041] 11 Tooling platform 12 Movable support mechanism

[0042] 13 Positioning rod 14 Detection ring

[0043] 15 Lifting support mechanism 16 End pushing mechanism

[0044] 17 Side pushing mechanism 18 Arm joint model identification line

[0045] 121 Platform guide rail 122 Transverse moving slider

[0046] 123 Support seat body 124 Seat body guide rail

[0047] 125 Vertical moving slider 126 Positioning plate

[0048] 127 Positioning hole 128 Transverse moving locking connecting piece

[0049] 129 Vertical moving locking connecting piece 1210 Slider guide rail

[0050] 1211 Positioning plate slider 1212 Slider locking connecting piece

[0051] 2 Arm joint

[0052] 21 Arm joint body 22 Bushing Specific embodiments

[0053] The following will describe in detail the specific embodiments of the embodiments of the present invention with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining and illustrating the embodiments of the present invention, and are not used to limit the embodiments of the present invention.

[0054] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0055] In the embodiments of the present invention, unless otherwise stated, the orientation terms such as "upper, lower, top, bottom" are generally used in reference to the directions shown in the drawings or in terms of the vertical, perpendicular or gravitational directions for describing the relative positions of the components to each other.

[0056] The present invention will be described in detail below with reference to the drawings and in conjunction with exemplary embodiments.

[0057] As Figures 1 to 9 shown, an exemplary embodiment of the present invention provides an arm joint bushing position detection tooling 1, which includes a tooling platform 11, a three-way positioning system and a bushing detection system.

[0058] Specifically, the tooling platform 11 is used to carry the arm joint 2, and the arm joint 2 includes an arm joint body 21 and a plurality of bushings 22 welded to the arm joint body 21. The three-way positioning system is arranged on the tooling platform 11 and is used to position the arm joint 2 along the length direction, width direction and height direction of the tooling platform 11 respectively, so as to ensure the stability of the arm joint 2 during the process of detecting the bushing position and avoid affecting the detection result. The bushing detection system is arranged on the tooling platform 11 and is used to detect the positions of the plurality of bushings 22 on the arm joint 2 positioned by the three-way positioning system. The bushing detection system can be manually controlled to operate, but it is not completely freely controlled by humans like measuring tools such as steel tape measures. Instead, it needs to be used according to the detection principle of the bushing detection system. Therefore, the measurement accuracy is determined by the structural characteristics of the bushing detection system itself and does not depend on manual operation skills or experience, which can greatly reduce the influence of subjective factors on the detection results.

[0059] Based on the above settings, when detecting the bushing position of the arm joint 2 through this exemplary embodiment, first place the arm joint 2 on the tooling platform 11, position the arm joint 2 along the length direction, width direction and height direction of the tooling platform 11 respectively through the three-way positioning system, and then detect the positions of the plurality of bushings 22 on the positioned arm joint 2 through the bushing detection system. This can eliminate cumbersome steps such as manually pulling a steel tape measure, at least to a certain extent reduce the measurement difficulty and operation intensity of the operator, improve the measurement efficiency, and the bushing detection system is dedicated to the detection of the arm joint bushing position. Its measurement reference and consistency can be effectively controlled through reasonable design, thereby improving the measurement accuracy.

[0060] In one embodiment, the bushing detection system includes a plurality of bushing detection groups arranged at intervals in sequence along the length direction of the tooling platform 11 to respectively detect the positions of the bushings 22 at different positions on the arm joint 2. Each bushing detection group includes two movable support mechanisms 12, a positioning rod 13 and two detection rings 14.

[0061] More specifically, two movable support mechanisms 12 are each formed with a positioning hole 127. The two movable support mechanisms 12 are arranged at intervals along the width direction of the tooling platform 11 and can both displace along the length direction and the height direction of the tooling platform 11, so that the positioning holes 127 in the two movable support mechanisms 12 can be coaxially aligned along the width direction of the tooling platform 11. The positioning rod 13 is detachably passed through the two positioning holes 127 that are coaxially aligned along the width direction of the tooling platform 11, and the two detection rings 14 are both detachably slidably sleeved on the positioning rod 13.

[0062] The detection principle of this embodiment will be explained in detail below:

[0063] After the arm section 2 is positioned by the three-way positioning system, adjust the positions of the two movable support mechanisms 12 in one of the bushing detection groups along the length direction and the height direction of the tooling platform 11, so that the positioning holes 127 in the two movable support mechanisms 12 are coaxially aligned along the width direction of the tooling platform 11, and at the same time, the positioning holes 127 are also aligned with the bushing holes of the two bushings 22 on the arm section 2 along the width direction of the tooling platform 11. Then pass the positioning rod 13 through the two positioning holes 127 and the two bushing holes, and during this process, also sleeve the two detection rings 14 on the positioning rod 13. After the connection is completed, finely adjust the arm section 2, and slide the two detection rings 14 respectively towards the two bushing holes. To make the two detection rings 14 respectively fit concentrically with the two bushing holes, reference can be made to Figure 3 . Thus, determine to use these two bushing holes as the measurement reference.

[0064] Subsequently, the detection of the positions of the remaining bushings 22 can be started. The same as the first step is that the two bushings 22 aligned along the width direction of the tooling platform 11 can be detected by the corresponding bushing detection group. The difference from the first step is that after passing the positioning rod 13 through the two positioning holes 127 and the two bushing holes, there is no need to finely adjust the arm section 2 anymore. Just slide the two detection rings 14 respectively towards the two bushing holes until the two detection rings 14 are respectively close to the two bushings 22, and then observe whether the two detection rings 14 can respectively fit concentrically with the two bushing holes, and then it can be judged whether the position of the currently detected bushing 22 needs to be orthopedically corrected or modified.

[0065] The judgment principle is: If the position of the currently detected bushing 22 meets the design requirements, that is, the relative position of the currently detected bushing 22 and the bushing 22 in the first step meets the design requirements, then the bushing hole of the currently detected bushing 22 should fit concentrically with the corresponding detection ring 14. Otherwise, if it does not meet the design requirements, then the bushing hole of the currently detected bushing 22 should be eccentrically aligned with the corresponding detection ring 14. Reference can be made to Figure 4 .

[0066] In other words, when the operator observes that the detection ring 14 is concentrically and fittingly aligned with the bushing hole, it can be determined that the position of the bushing 22 is correct and no orthopedic correction or modification is required. When the operator observes that the detection ring 14 is eccentrically aligned with the bushing hole, it can be determined that the position of the bushing 22 is incorrect and orthopedic correction or modification is needed. And in the case of eccentric alignment, by observing the deviation direction of the bushing 22 relative to the detection ring 14, the actual position of the bushing 22 can be accurately determined as to how it deviates from the designed position. For example, taking Figure 4 as an example, it can be seen that the bushing 22 in the figure deviates to the right by a certain distance relative to the detection ring 14, which means that the actual position of the bushing 22 is more to the right than the designed position.

[0067] Furthermore, a plurality of concentrically arranged circular scales can be provided on the detection ring 14 so as to directly observe the deviation value of the bushing 22, thereby enabling more accurate and targeted orthopedic correction or modification. For example, taking Figure 4 as an example, when the bushing 22 deviates to the right by a certain distance relative to the detection ring 14, the left edge of the bushing hole will enter into the plurality of circular scales of the detection ring 14, thereby indicating the specific deviation value. At this time, the detection ring 14 can be made of a transparent material to more clearly observe the specific scale value indicated by the left edge of the bushing hole.

[0068] In one embodiment, referring to Figures 5 to 9 , the movable support mechanism 12 includes a transverse movement mechanism, a support seat body 123, a vertical movement mechanism, and a positioning plate 126.

[0069] Specifically, the transverse movement mechanism includes a platform guide rail 121 extending in the length direction on the tooling platform 11 and a transverse movement slider 122 slidably engaged with the platform guide rail 121. The support seat body 123 is fixedly arranged on the transverse movement slider 122. By the transverse movement slider 122 sliding on the platform guide rail 121, the support seat body 123 can synchronously displace with the transverse movement slider 122. In addition, the vertical movement mechanism includes a seat body guide rail 124 extending in the height direction on the support seat body 123 and a vertical movement slider 125 slidably engaged with the seat body guide rail 124. The positioning plate 126 is formed with the aforementioned positioning hole 127 and is arranged on the vertical movement slider 125. By the vertical movement slider 125 sliding on the seat body guide rail 124, the positioning plate 126 can displace with the vertical movement slider 125.

[0070] It can be seen that by providing the transverse movement mechanism and the vertical movement mechanism, the position of the positioning hole 127 can be adjusted in the length direction and the height direction along the tooling platform 11, so that the positioning holes 127 of the two movable support mechanisms 12 in the bushing detection group can be adjusted to be coaxially aligned in the width direction of the tooling platform 11.

[0071] Referring to Figure 8, the transverse movement slider 122 can be formed with a transverse movement locking hole, and the transverse movement mechanism can further include a transverse movement locking connecting piece 128 for passing through the transverse movement locking hole to be fixed to the tooling platform 11. For example, the transverse movement locking connecting piece 128 can be a bolt. When it is necessary to move the transverse movement slider 122, the insertion depth of the transverse movement locking connecting piece 128 can be adjusted to disengage it from the tooling platform 11. When it is necessary to lock the transverse movement slider 122, the insertion depth of the transverse movement locking connecting piece 128 can be adjusted to press it against the tooling platform 11. Under the action of friction, the transverse movement slider 122 cannot move.

[0072] Referring to Figures 5 to 7 , the vertical movement slider 125 can be formed with a vertical movement locking hole, and the vertical movement mechanism can further include a vertical movement locking connecting piece 129 for passing through the vertical movement locking hole to be fixed to the support seat body 123. For example, the vertical movement locking connecting piece 129 can be a bolt. When it is necessary to move the vertical movement slider 125, the insertion depth of the vertical movement locking connecting piece 129 can be adjusted to disengage it from the support seat body 123. When it is necessary to lock the vertical movement slider 125, the insertion depth of the vertical movement locking connecting piece 129 can be adjusted to press it against the support seat body 123. Under the action of friction, the vertical movement slider 125 cannot move.

[0073] Referring to Figure 1 and Figure 5 , in at least a part of the movable support mechanism 12 (such as Figure 1 the two movable support mechanisms 12 at the left end in

[0074] Referring again to Figures 5 to 7, the positioning plate slider 1211 can be formed with a slider locking hole. The movable support mechanism 12 can include a slider locking connector 1212 for passing through the slider locking hole to fix to the slider guide 1210. For example, the slider locking connector 1212 can be a bolt. When it is necessary to move the positioning plate slider 1211, the insertion depth of the slider locking connector 1212 can be adjusted to disengage it from the slider guide 1210. When it is necessary to lock the positioning plate slider 1211, the insertion depth of the slider locking connector 1212 can be adjusted to press against the slider guide 1210. Under the action of friction, the positioning plate slider 1211 cannot move.

[0075] Refer to Figure 8 and Figure 9 , on the tabletop of the tooling platform 11, a plurality of arm section model identification lines 18 adjacent to the platform guide 121 and arranged in sequence along the length direction can be provided. The plurality of arm section model identification lines 18 correspond to a variety of arm section models one by one. Thus, according to the specific model of the arm section 2 carried on the tooling platform 11, the position of the transverse movement slider 122 can be quickly adjusted, thereby improving the detection speed.

[0076] Refer to Figure 1 and Figure 2 , the three-way positioning system includes a lifting support mechanism 15 for supporting the arm section 2, an end pushing mechanism 16 for pushing the end of the arm section 2 along the length direction, and a side pushing mechanism 17 for pushing the side of the arm section 2 along the width direction.

[0077] Before detection, first place the arm section 2 on a plurality of lifting support mechanisms 15, and level the arm section 2 by adjusting the plurality of lifting support mechanisms 15. Then, through the combined adjustment of the end pushing mechanism 16 and a plurality of side pushing mechanisms 17, the arm section 2 can be adjusted to the middle position along the width direction of the tooling platform 11 to achieve centering. It can be seen that by using the lifting support mechanism 15, the end pushing mechanism 16, and the side pushing mechanism 17, the arm section 2 can be three-way positioned before detection, ensuring the stability of the arm section 2 and being beneficial to improving the detection accuracy.

[0078] Furthermore, as Figure 1 and Figure 2 shown, the lifting support mechanism 15 can be formed as a screw-type support mechanism, and the end pushing mechanism 16 and the side pushing mechanism 17 can both be formed as screw-type pushing mechanisms. The screw-type support mechanism and the screw-type pushing mechanism can both be provided with handles for easy manual operation.

[0079] In summary, the arm section bushing position detection tooling 1 of this exemplary embodiment further has at least the following advantages:

[0080] 1) Simple structure, easy to operate, and high detection efficiency;

[0081] 2) The cost is greatly reduced, with less cost input and quick return on investment;

[0082] 3) There is no need to set up precise transmission and electronic devices, and the maintenance is simple and convenient, which is suitable for the self-inspection before the transfer process in the boom welding workshop with relatively harsh environment.

[0083] The optional implementation manners of the embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above implementation manners. Within the technical concept scope of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention.

[0084] In addition, it should be noted that the various specific technical features described in the above specific implementation manners can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not separately describe various possible combination manners.

[0085] In addition, any combination can be made among the various different implementation manners of the embodiments of the present invention, as long as it does not violate the idea of the embodiments of the present invention, and it should also be regarded as the content disclosed by the embodiments of the present invention.

Claims

1. An arm joint bushing position detection tooling, characterized in that The arm joint bushing position detection tooling (1) includes a tooling platform (11), a three-way positioning system, and a bushing detection system. The tooling platform (11) is used to carry the arm joint (2). The three-way positioning system is arranged on the tooling platform (11) and is used to position the arm joint (2) along the length direction, width direction, and height direction of the tooling platform (11) respectively. The bushing detection system is arranged on the tooling platform (11) and is used to detect the positions of multiple bushings (22) on the arm joint (2) positioned by the three-way positioning system. The bushing detection system includes multiple bushing detection groups arranged at intervals along the length direction. Each bushing detection group includes two movable support mechanisms (12), a positioning rod (13), and two detection rings (14). Both of the two movable support mechanisms (12) are formed with positioning holes (127). The two movable support mechanisms (12) are arranged at intervals along the width direction and can both displace along the length direction and the height direction so that the positioning holes (127) in the two movable support mechanisms (12) can be coaxially aligned along the width direction. The positioning rod (13) is detachably passed through the two positioning holes (127) coaxially aligned along the width direction. Both of the two detection rings (14) are detachably slidably sleeved on the positioning rod (13). The movable support mechanism (12) includes a transverse movement mechanism, a support seat body (123), a vertical movement mechanism, and a positioning plate (126). The transverse movement mechanism includes a platform guide rail (121) extending along the length direction on the tooling platform (11) and a transverse movement slider (122) slidably matched with the platform guide rail (121). The support seat body (123) is fixedly arranged on the transverse movement slider (122). The vertical movement mechanism includes a seat body guide rail (124) extending along the height direction on the support seat body (123) and a vertical movement slider (125) slidably matched with the seat body guide rail (124). The positioning plate (126) is arranged on the vertical movement slider (125) and is formed with the positioning hole (127). The transverse movement slider (122) is formed with a transverse movement locking hole. The transverse movement mechanism further includes a transverse movement locking connecting piece (128) for passing through the transverse movement locking hole to be fixed to the tooling platform (11). The vertical movement slider (125) is formed with a vertical movement locking hole. The vertical movement mechanism further includes a vertical movement locking connecting piece (129) for passing through the vertical movement locking hole to be fixed to the support seat body (123). In at least a part of the movable support mechanism (12), the vertical translation slider (125) includes a first vertical translation slider and a second vertical translation slider that are respectively in sliding fit with the seat guide rail (124). The positioning plate (126) includes a first positioning plate and a second positioning plate. The first positioning plate is fixedly connected to the first vertical translation slider. The second vertical translation slider is fixedly connected with a slider guide rail (1210) extending along the length direction. The second positioning plate is fixedly connected with a positioning plate slider (1211) that is in sliding fit with the slider guide rail (1210).

2. The arm joint bushing position detection tooling according to claim 1, characterized in that, A plurality of concentric ring scales are provided on the detection ring (14).

3. The arm joint bushing position detection tooling according to claim 1, wherein, The positioning plate slider (1211) is formed with a slider locking hole. The movable support mechanism (12) includes a slider locking connector (1212) for passing through the slider locking hole to be fixed to the slider guide rail (1210).

4. The arm joint bushing position detection tooling according to claim 1, characterized in that, On the tabletop of the tooling platform (11), a plurality of arm section model marking lines (18) are provided adjacent to the platform guide rail (121) and arranged in sequence along the length direction.

5. The arm joint bushing position detection tooling according to claim 1, characterized in that The three-way positioning system includes a lifting support mechanism (15) for supporting the arm section (2), an end pushing mechanism (16) for pushing the end of the arm section (2) along the length direction, and a side pushing mechanism (17) for pushing the side of the arm section (2) along the width direction.

6. The position detection tooling for the arm joint bushing according to claim 5, characterized in that, The lifting support mechanism (15) is formed as a screw-type support mechanism, and both the end pushing mechanism (16) and the side pushing mechanism (17) are formed as screw-type pushing mechanisms.

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