A material return extension system for impact crusher

Abstract

The present invention belongs to the technical field of crushers, and specifically relates to a return material extension system for an impact crusher. The present invention includes a tail end telescopic device with a telescopic function arranged at the tail end of a return material conveying frame and a head end lifting device with a lifting function located at the head end of the return material conveying frame; the head end lifting device includes a four-link lifting assembly and a head support assembly for connecting the four-link lifting assembly and the return material conveying frame; the tail end telescopic device includes a telescopic cylinder fixed to the vehicle body and a tail support assembly for connecting the telescopic cylinder and the return material conveying frame. The present invention can realize the online folding and lifting functions of the return material conveying frame, thereby effectively improving the efficiency of the transportation operation of the impact crusher.

Description

Technical Field

[0001] The invention belongs to the technical field of crushers, and in particular relates to a material return extension system for an impact crusher. Background Art

[0002] Impact crusher is abbreviated as impact crusher. It is mainly used for material processing in metallurgy, chemical industry, building materials, hydropower and other industries that often need to be relocated, especially for pre-crushing of mobile stones in highways, railways, hydropower projects and other industries. When the impact crusher is working, first, the material is sent from the feed hopper to the feeder, and then the material is sent to the impact crusher through the vibration of the feeder. After crushing, the material falls to the conveyor, and the conveyor sends the material to the return material screen. The return material screen separates the finished product and the unfinished product through vibration; the unfinished material falls into the transition conveyor, and the transition conveyor transports the material to the return material conveyor rack, and then sends it back to the impact crusher for secondary return material processing, and the finished product is discharged from the discharge port. The traditional return material conveyor rack is an integral structure. Affected by the height of the return material, it is normal for the rack to be super high and super long; however, the super high and super long return material conveyor rack obviously causes the overall size of the impact crusher to increase, which makes the transportation operation extremely inconvenient. At present, when transporting an impact crusher, the return material conveyor frame needs to be completely disassembled, that is, the return material conveyor frame and the impact crusher need to be transported separately; after the impact crusher is transported to the operation site, the return material conveyor frame needs to be reassembled, which is obviously extremely cumbersome in operation and extremely low in transportation efficiency, thus causing many troubles in the actual use of the impact crusher. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and to provide a structurally reasonable and practical return material extension system for an impact crusher, which can realize the online folding and lifting functions of the return material conveyor frame, thereby effectively improving the efficiency of the transportation operation of the impact crusher.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A return material extension system for an impact crusher, characterized in that: the system comprises a rear end extension device arranged at the rear end of a return material conveying frame and having an extension function; and a head end lifting device located at the head end of the return material conveying frame and having a lifting function, wherein:

[0006] The head-end lifting device includes a four-link lifting assembly and a head-supporting assembly for connecting the four-link lifting assembly and the return material conveying frame; the four-link lifting assembly includes a first link fixed to the vehicle body, the head end of the second link in an L shape is hinged at the top end of the first link, the tail end of the second link is hinged to the head end of the third link in a 7 shape, the tail end of the third link is hinged to the head end of the fourth link in a V shape, the tail end of the fourth link is hinged to the first link, and each hinge is horizontally arranged to form a four-link structure on the plumb plane; when the four-link structure is in an initial state, the head end vertical rod section of the second link and the tail end vertical rod section of the fourth link are vertically fitted to each other, and the upper surface of the tail end cross bar section of the second link is aligned with the head end of the third link. The upper surfaces of the end cross bar sections are on the same horizontal plane, thereby forming a placement surface for the first support assembly to be placed; the four-link lifting assembly also includes a power cylinder for driving the four-link structure to form an initial and extended state, the cylinder wall of the power cylinder is hinged to the vehicle body, the piston rod end of the power cylinder extends obliquely upward and is hinged to the rod body of the tail end vertical bar section of the fourth link; the first support assembly includes a first support roller with a roller shaft perpendicular to the feeding direction of the return material conveyor frame, and the roller surface of the first support roller is hinged to the upper surface of the first end cross bar section of the third link through a first end hinge seat vertically arranged at the hinge axis; a first end bracket extends downward from the return material conveyor frame; the two ends of the first end bracket extend to the two ends of the first support roller and form a swivel matching relationship with it as the rotation axis is horizontal;

[0007] The tail end telescopic device includes a telescopic cylinder fixed to the vehicle body and a tail support assembly for connecting the telescopic cylinder and the return material conveyor frame; the tail support assembly includes a tail support roller whose roller length direction is perpendicular to the feeding direction of the return material conveyor frame, and the roller surface of the tail support roller is rotatably matched on the return material conveyor frame through a tail end hinge seat arranged vertically by a hinge axis; the piston rod end of the telescopic cylinder extends horizontally toward the tail end of the return material conveyor frame and is fixedly connected to the tail end bracket; the two ends of the tail end bracket extend to the two ends of the tail support roller and form a rotational matching relationship with it as a horizontal line of the rotation axis.

[0008] Preferably, the hinge between the second link and the third link is the first hinge point, and the hinge between the third link and the fourth link is the second hinge point. When the four-link structure is in an initial state, in the projection in the top view direction, the second hinge point is located on the line between the first hinge point and the head end hinge seat.

[0009] Preferably, the V-shaped angle formed by the shaft of the fourth connecting rod is an obtuse angle; when the four-bar connecting rod structure is in an extended state, the tail end vertical rod section of the second connecting rod and the tail end inclined rod section of the third connecting rod are parallel to each other.

[0010] Preferably, the tail end of the fourth connecting rod is hinged to the middle section of the first connecting rod, and the bottom end of the first connecting rod constitutes a hinged end to which the cylinder wall end of the power cylinder can be hinged.

[0011] Preferably, the head end bracket is located below the head end of the return material conveyor frame, and the tail end bracket is arranged in a gantry shape above the tail end of the return material conveyor frame.

[0012] Preferably, the power cylinder and the telescopic cylinder are both hydraulic cylinders.

[0013] The beneficial effects of the present invention are:

[0014] 1) The present invention arranges a front end lifting device and a rear end telescopic device at the front and rear ends of the return material conveyor frame respectively, thereby utilizing the extension method of "front oblique lifting + rear horizontal lifting", thereby achieving the purpose of the return material conveyor frame changing from a small inclination close to the vehicle body during transportation to a large inclination away from the vehicle body during normal work.

[0015] Specifically, for the head-end lifting device, the present invention improves the structure of the traditional four-bar structure: on the one hand, by forming the tail-end cross bar section of the first connecting rod and the tail-end cross bar section of the second connecting rod into the same horizontal line, a head support assembly is provided with a placement platform, which does not affect the normal extension path of the return material conveyor frame while ensuring the reliable load-bearing effect of the return material conveyor frame. On the other hand, the head-end vertical bar section of the second connecting rod and the tail-end vertical bar section of the fourth connecting rod are parallel to each other, which not only ensures the load-bearing property and structural compactness, but also minimizes the movement stroke of the power cylinder. Through the above-mentioned coordination, during actual operation, the power cylinder only needs to apply a slight force to the tail-end vertical bar section, so that the entire four-bar structure can produce a large-scale lifting and unfolding action, the working sensitivity and reliability are extremely high, and the online folding and lifting action of the return material conveyor frame is obvious. As for the tail end telescopic device, whenever the front end lifting device produces an outward and upward oblique lifting action, so that the front end of the return material conveyor rack gradually moves away from the vehicle body, the tail end telescopic device will also move accordingly, and push the tail end of the return material conveyor rack to move away from the vehicle body synchronously, with extremely high working coordination.

[0016] In addition, it is worth noting that due to the particularity of the return material conveyor rack, the height of its tail end is usually not adjusted. Through the horizontally pushed tail end telescopic device, the tail end of the return material conveyor rack is only pushed outward horizontally, thereby ensuring that the return material conveyor rack always has an action reference point, that is, the tail end point, during the entire action process; in this way, no matter how the head end of the return material conveyor rack swings and rises and falls, the final position of the entire return material conveyor rack is always determined. When the impact crusher arrives at the work site, the return material conveyor rack can rely on the above-mentioned action reference point to quickly extend and realize self-extension and self-calibration functions, thereby eliminating the on-site calibration process, which is obviously very in line with the current fast-paced and high-efficiency construction site production needs.

[0017] Through the above-mentioned matching structure, the present invention can realize the online folding and lifting functions of the return material conveying frame, thereby effectively improving the efficiency of the transportation operation of the impact crusher.

[0018] 2) For the first support assembly, its function is to provide the compensation for the return material conveyor frame when it is folded and lifted, to ensure that the return material conveyor frame is not stuck due to assembly errors or the matching state with other auxiliary components. The first support assembly includes an X-axis rotation system formed by the first support roller and the first end hinge seat arranged vertically with the hinge axis, and a Y-axis rotation system formed by the first support roller and the first end bracket, so as to flexibly achieve the above-mentioned action compensation effect.

[0019] 3) The second hinge point, that is, the hinge point of the third link and the fourth link, should be arranged at a particular position. In the top view projection, the second hinge point should be located on the line between the first hinge point and the first end hinge seat, so as to ensure that in the initial state, when the return material conveyor rack is placed on the shelf surface, the third link and the fourth link can reliably bear the huge mass of the return material conveyor rack, thereby ensuring the compactness of the structure while ensuring the working stability and reliable load-bearing effect of the overall structure.

[0020] 4) When the four-link structure is in a fully extended state, the return material conveyor frame is in a high-angle state. At this time, on the one hand, the concave space formed by the unique "7" structure of the third link plays the function of accommodating the "L"-shaped corner of the second link, ensuring the compactness of the structure. On the other hand, the tail end vertical rod section of the second link and the tail end inclined rod section of the third link are parallel to each other, so that when the four-link structure is fully extended, the second link and the third link form a dead point-like matching state, thereby ensuring that the present invention can still work reliably and stably under the huge weight of the return material conveyor frame itself and the huge bump force during operation, and is extremely practical.

[0021] 5) As for the first connecting rod, it can be directly integrated into the vehicle body. The present invention extends the first connecting rod downward, so that while cooperating with the second connecting rod and the fourth connecting rod, it also plays the function of fixing the base relative to the power cylinder, thereby realizing the independence of the overall structure. During actual assembly, the present invention can be designed and manufactured separately, and then directly welded and assembled relative to the vehicle body. Even for the existing impact crusher, due to the independent installation characteristics of the present invention, it is obvious that the existing impact crusher can be directly upgraded on site without the need to purchase a new model. The cost of upgrading can be significantly reduced, and it is also more conducive to being accepted by the production enterprises.

[0022] 6) The head end bracket is located below the head end of the return material conveyor rack, which can avoid the equipment height being too high due to being arranged above the return material conveyor rack; similarly, the tail end bracket is arranged in a gantry shape above the tail end of the return material conveyor rack. This is because the tail end of the return material conveyor rack is close to the ground, so the tail end bracket needs to be installed above the tail end of the return material conveyor rack to ensure its functionality. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the installation position of the four-link lifting assembly in the initial state;

[0024] Figure 2 It is a front view of the four-link lifting assembly in the initial state;

[0025] Figure 3 for Figure 2 The three-dimensional state diagram of

[0026] Figure 4 It is a front view of the rear end telescopic device in the extended state;

[0027] Figure 5 for Figure 4 The three-dimensional state diagram of

[0028] Figure 6 It is a front view of the four-link lifting assembly when it starts to extend;

[0029] Figure 7 for Figure 6 The three-dimensional state diagram of

[0030] Figure 8 This is a front view of the four-link lifting assembly after it is fully extended;

[0031] Fig. 9 for Figure 8 The three-dimensional state diagram of

[0032] Fig.10 It is a schematic diagram of the installation position of the four-link lifting assembly when it is in the extended state.

[0033] The actual correspondence between the reference numerals and component names of the present invention is as follows:

[0034] a-Return material conveyor rack

[0035] 10-head end lifting device 11-four-link lifting assembly

[0036] 11a-first link 11b-second link 11c-third link 11d-fourth link

[0037] 111- head end vertical bar section 112- tail end vertical bar section 113- tail end horizontal bar section

[0038] 114-head end cross bar section 115-tail end inclined bar section

[0039] 12-First support component

[0040] 12a-first roller 12a 12b-first end hinged seat 12b 12c-first end bracket 12c

[0041] 13-Power Cylinder

[0042] 20-Tail telescopic device 21-Telescopic cylinder 22-Tail stock assembly

[0043] 22a- tail roller 22b- tail end hinge seat 22c- tail end bracket DETAILED DESCRIPTION

[0044] For ease of understanding, the specific structure and working mode of the present invention are further described below in conjunction with the accompanying drawings:

[0045] The specific structure of the present invention refers to Figure 1-10 As shown, its main components include a front end lifting device 10 and a rear end telescopic device 20, wherein:

[0046] Head end lifting device 10

[0047] The head end lifting device 10 is arranged at the head end of the return material conveyor frame a, and its function is to lift the return material conveyor frame with an oblique upward lifting force and achieve a timely retraction and reset effect. Figure 1-10 shown.

[0048] The head end lifting device 10 is composed of two parts: a four-link lifting assembly 11 and a head support assembly 12. The four-link lifting assembly 11 is a variant structure based on the traditional four-link, including a first link 11a fixed to the vehicle body. The top end of the first link 11a is hinged to the head end of the "L"-shaped second link 11b, the tail end of the second link 11b is hinged to the head end of the "7"-shaped third link 11c, the tail end of the third link 11c is hinged to the head end of the "V"-shaped fourth link 11d, and the tail end of the fourth link 11d is hinged to the middle section of the first link 11a. All hinges are horizontally arranged, so as to form a four-link structure on the vertical plane. For details, refer to Figure 2-3 shown.

[0049] When the above four-bar linkage is in the Figure 2-5 In the initial state shown, the head end vertical rod segment 111 of the second link 11b and the tail end vertical rod segment 112 of the fourth link 11d are vertically attached to each other, and the upper surface of the tail end cross rod segment 113 of the second link 11b and the upper surface of the head end cross rod segment 114 of the third link 11c are on the same horizontal plane, thereby forming a shelf surface for the head support assembly 12 to rest on. At the same time, the hinge between the second link 11b and the third link 11c is the first hinge point, and the hinge between the third link 11c and the fourth link 11d is the second hinge point. When the four-link structure is in the initial state, in the projection in the top view direction, the second hinge point is located on the line between the first hinge point and the head end hinge seat 12b. When the four-link structure is in the initial state shown in the figure, the head end vertical rod segment 111 of the second link 11b is in the initial state, and the head end vertical rod segment 112 of the fourth link 11d is in the initial state. When the four-link structure is in the initial state shown in the figure, the head end vertical rod segment 111 of the second link 11b is in the initial state, and the head end vertical rod segment 112 of the fourth link 11d is in the initial state, and the head end vertical rod segment 112 of the fourth link 11c ... Figure 8-10In the extended state shown, the vertical rod section 111 at the tail end of the second connecting rod 11b and the inclined rod section 115 at the tail end of the third connecting rod 11c are parallel to each other to ensure their load-bearing performance and structural compactness.

[0050] On the basis of the above structure, the four-link lifting assembly 11 also includes a power cylinder 13 for driving the four-link structure to form the above-mentioned initial and extended states. The power cylinder 13 is a hydraulic cylinder to ensure that a huge driving force is generated on the four-link structure. The cylinder wall of the power cylinder 13 is hinged to the vehicle body, and the piston rod end of the power cylinder 13 extends upward and is hinged to the tail end vertical rod section 112 of the fourth link 11d.

[0051] For the first supporting assembly 12, it can actually be regarded as an X-axis rotating mechanism formed by the first supporting roller 12a and the first end hinged seat 12b and a Y-axis rotating mechanism formed by the first supporting roller 12a and the first end bracket 12c with the first supporting roller 12a as the center, so as to ensure that the return material conveying frame a can always be in a stable posture when the four-link lifting assembly 11 performs the initial and extending actions.

[0052] Tail end telescopic device 20

[0053] The specific structure of the tail end telescopic device 20 is shown in FIG. Figure 3 and Figure 5 As shown, it includes a telescopic cylinder 21 fixed to the vehicle body and a tail support assembly 22 for connecting the telescopic cylinder 21 and the return material conveying frame a.

[0054] The structure of the tail support assembly 22 is similar to that of the head support assembly 12, that is, with the tail support roller 22a as the center, the X-axis rotation mechanism formed by the tail support roller 22a and the tail end hinge seat 22b and the Y-axis rotation mechanism formed by the tail support roller 22a and the tail end bracket 22c, so that when the four-link lifting assembly 11 performs the initial and extension actions, it is always ensured that the return material conveyor frame a can always be in a stable posture. The difference is that the head end bracket 12c needs to be arranged below the head end of the return material conveyor frame a, and the tail end bracket 22c needs to be arranged above the tail end of the return material conveyor frame a, refer to Figure 3 shown.

[0055] The front end hinge seat 12b and the rear end hinge seat 22b are both through-type hinged columns. Figure 3 In actual operation, each articulated seat can also be designed as a conventional articulated ear or other articulated structure, which will not be described in detail here.

[0056] For ease of understanding, here we combine Figure 1-10 , the specific working process of the present invention is described as follows:

[0057] 1) The impact crushing of the present invention is applied in the following Figure 1In the transport state shown in FIG. 1 , it can be seen that the telescopic cylinder 21 at the rear end telescopic device 20 is completely in the return state, so that Figure 2 In the front view shown, the entire return material conveyor frame a is in a straightened state that is completely in contact with the vehicle body. The four-link jacking assembly 11 at the head end lifting assembly is in the initial state, at which the tail end vertical bar section 111 of the second link 11b and the head end horizontal bar section 114 of the third link 11c cooperate with each other to form a resting surface for the head support assembly 12 and even the head end of the entire return material conveyor frame a to rest. Since the above resting surface forms a planar structure, even under the bumpy force during transportation, it will not have any impact on the transportation stability of the return material conveyor frame a.

[0058] 2) When the impact crusher arrives at the operation site, the present invention performs the following actions:

[0059] a. The rear end telescopic device 20 starts to move, and the telescopic cylinder 21 rises, pushing the rear end of the return material conveyor frame a away from the vehicle body. For details, refer to Figure 4-5 shown.

[0060] b. When the tail end of the return material conveyor frame a reaches the specified position, the head end lifting device 10 starts to act:

[0061] First, the power cylinder 13 is activated to push the fourth connecting rod 11d to move upward around the first connecting rod 11a, so that the entire four-bar structure moves with it, gradually forming a Figure 6-7 After that, the power cylinder 13 continues to lift until the "L"-shaped corner of the second connecting rod 11b is inserted into the concave space formed by the unique "7" structure of the third connecting rod 11c, and at the same time, the tail end vertical rod section 111 of the second connecting rod 11b and the tail end inclined rod section 115 of the third connecting rod 11c are parallel to each other to form an action dead point. Finally, the head end lifting device 10 is formed as shown. Figure 8-9 fully expanded state.

[0062] When the impact crusher arrives at the work site, the above-mentioned whole action process can be summarized as follows: the rear end telescopic device 20 pushes the rear end of the return material conveyor frame a away from the impact crusher body to the right position, and the front end lifting device 10 lifts the front end of the return material conveyor frame a obliquely upward to produce a movement around its own rear end until the front end of the return material conveyor frame a moves to the right position. At this time, the overall working state of the return material conveyor frame a is as shown in FIG. Fig.10 As shown. Fig.10 In this state, the impact crusher or impact crusher can work normally. When the impact crusher is finished and needs to move to another work site, the above steps can be reversed. Obviously, in the above whole operation process, the return material conveyor frame a is assembled on the impact crusher body, and is not disassembled separately, which is more flexible and convenient to use, and more effective in mobile operations at multiple work sites.

[0063] Of course, the above is only one specific embodiment of the present invention. In actual operation, equivalent replacement of the power source, such as adaptively replacing the power cylinder 13 and the telescopic cylinder 21 with other power components, and fine-tuning the shape of each connecting rod constituting the four-bar structure without affecting its own working performance, and transforming the corresponding rollers at the head support assembly 12 and the tail support assembly 22 into cylindrical, prismatic or even curved rod shapes, etc., such conventional structural changes made on the basis of the known structure of the present invention should be regarded as equivalent or similar designs and fall within the protection scope of the present invention.

Claims

1. A material return stretching system for an impact crusher, characterized in that: The system comprises a rear end telescopic device (20) arranged at the rear end of the return material conveyor frame and having a telescopic function; and a front end lifting device (10) located at the front end of the return material conveyor frame and having a lifting function, wherein: The head end lifting device (10) comprises a four-link lifting assembly (11) and a head support assembly (12) for connecting the four-link lifting assembly (11) and a return material conveying frame; the four-link lifting assembly (11) comprises a first link (11a) fixed to the vehicle body, the head end of an "L"-shaped second link (11b) being hinged at the top end of the first link (11a), the tail end of the second link (11b) being hinged to the head end of a "7"-shaped third link (11c), and the third link (11c) being hinged to the head end of a "7"-shaped third link ) is hinged to the head end of a "V"-shaped fourth connecting rod (11d), and the tail end of the fourth connecting rod (11d) is hinged to the first connecting rod (11a), and each hinge is arranged horizontally, thereby forming a four-link structure on the plumb plane; when the four-link structure is in an initial state, the head end vertical rod segment (111) of the second connecting rod (11b) and the tail end vertical rod segment (112) of the fourth connecting rod (11d) are vertically attached to each other, and the upper surface of the tail end horizontal rod segment (113) of the second connecting rod (11b) is in contact with the first connecting rod (11a). The upper surfaces of the front end crossbar section (114) of the third connecting rod (11c) are on the same horizontal plane, thereby forming a placement surface for the head support assembly (12) to rest on; the four-link lifting assembly (11) further comprises a power cylinder (13) for driving the four-link structure to form an initial state and an extended state, the cylinder wall of the power cylinder (13) being hinged to the vehicle body, and the piston rod end of the power cylinder (13) extending obliquely upward and being hinged to the rod body of the rear end vertical rod section (112) of the fourth connecting rod (11d). The first support assembly (12) comprises a first support roller (12a) whose roller shaft is perpendicular to the feeding direction of the return material conveyor frame, and the roller surface of the first support roller (12a) is hinged to the upper surface of the first end cross bar section (114) of the third connecting rod (11c) through a first end hinge seat (12b) vertically arranged at the hinge axis; a first end bracket (12c) extends downward from the return material conveyor frame; two ends of the first end bracket (12c) extend to two ends of the first support roller (12a) and form a swivel matching relationship with the first support roller (12a) with the rotation axis being a horizontal line; The tail end telescopic device (20) comprises a telescopic cylinder (21) fixed to the vehicle body and a tail support assembly (22) for connecting the telescopic cylinder (21) and the return material conveyor frame; the tail support assembly (22) comprises a tail support roller (22a) whose roller length direction is perpendicular to the feeding direction of the return material conveyor frame, and the roller surface of the tail support roller (22a) is rotatably matched on the return material conveyor frame through a tail end hinge seat (22b) arranged vertically with a hinge axis; the piston rod end of the telescopic cylinder (21) extends horizontally toward the tail end of the return material conveyor frame and is fixedly connected to the tail end bracket (22c); the two ends of the tail end bracket (22c) extend to the two ends of the tail support roller (22a) and form a rotatable matching relationship with the tail support roller (22a) with the rotation axis being a horizontal line.

2. The material return and stretching system for an impact crusher according to claim 1, characterized in that: The hinge point between the second link (11b) and the third link (11c) is the first hinge point, the hinge point between the third link (11c) and the fourth link (11d) is the second hinge point, and when the four-link structure is in an initial state, in the projection in the top-view direction, the second hinge point is located on the line between the first hinge point and the head end hinge seat (12b).

3. The material return and stretching system for an impact crusher according to claim 2, characterized in that: The V-shaped angle formed by the rod body of the fourth connecting rod (11d) is an obtuse angle; when the four-link structure is in an extended state, the vertical rod section (111) at the head end of the second connecting rod (11b) and the inclined rod section (115) at the tail end of the third connecting rod (11c) are parallel to each other.

4. A material return stretching system for an impact crusher according to claim 1, 2 or 3, characterized in that: The tail end of the fourth connecting rod (11d) is hinged to the middle section of the first connecting rod (11a), and the bottom end of the first connecting rod (11a) constitutes a hinged end to which the cylinder wall end of the power cylinder (13) can be hinged.

5. A material return stretching system for an impact crusher according to claim 1, 2 or 3, characterized in that: The head end bracket (12c) is located below the head end of the return material conveying frame, and the tail end bracket (22c) is arranged in a gantry shape above the tail end of the return material conveying frame.

6. A material return stretching system for an impact crusher according to claim 1, 2 or 3, characterized in that: The power cylinder (13) and the telescopic cylinder (21) are both hydraulic cylinders.

Images