Hydraulic oil cylinder for hydraulic cargo elevator

Abstract

The invention relates to the technical field of hydraulic oil cylinders, in particular to a hydraulic oil cylinder for a hydraulic cargo elevator, which comprises a cylinder body, a piston mechanism, a protection mechanism, a partition plate and a conveying mechanism are sequentially arranged in the cylinder body from top to bottom, and a push rod is fixedly connected to the upper surface of the piston mechanism. A first oil inlet pipe is fixedly connected to the position, located between the piston mechanism and the partition plate, of the outer circumferential face of the cylinder body in a penetrating mode, the protection mechanism comprises a connecting piece arranged on the lower side of the piston mechanism, a cross-shaped supporting plate is fixedly connected to the bottom end of the connecting piece, and a protection piece used for safety limiting is arranged on the cross-shaped supporting plate. Secondary safety limiting can be carried out in the working process of the hydraulic oil pump through the arrangement of the protection mechanism, when the hydraulic oil pump has an unexpected situation and hydraulic supporting force disappears, the protection mechanism can carry out secondary supporting on the pushing rod at the moment, harm caused by the unexpected situation is reduced, and the risk that the cargo elevator rapidly falls down is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic cylinders, and in particular to a hydraulic cylinder for a hydraulic freight elevator. Background Art

[0002] The freight elevator hydraulic cylinder is an actuator in the hydraulic system, which is specially used in hydraulic freight elevators to convert hydraulic energy into mechanical energy to achieve the vertical lifting movement of the freight elevator car. It pushes the piston to move linearly in the cylinder body through the pressure of the hydraulic oil, thereby driving the freight elevator parts connected to the piston to rise or fall.

[0003] However, when the hydraulic cylinder is under relatively large pressure, when the pressure approaches the critical value of the hydraulic cylinder, the pressure on the sealing gasket between the piston and the cylinder body of the hydraulic cylinder gradually increases, and it is easy to deform, which will cause the sealing between the piston and the cylinder body to decrease, and the piston may become unstable and slide downward; when an unexpected situation occurs and the piston completely loses its supporting force, the freight elevator may fall rapidly, which may easily cause a serious safety accident. Summary of the invention

[0004] Therefore, the present invention provides a hydraulic cylinder for a hydraulic freight elevator, which solves the above technical problems.

[0005] The present invention provides a hydraulic cylinder for a hydraulic freight elevator, comprising a cylinder body, wherein a piston mechanism, a protection mechanism, a partition plate and a conveying mechanism are sequentially arranged inside the cylinder body from top to bottom, a push rod is fixedly connected to the upper surface of the piston mechanism, and the outer circumferential surface of the cylinder body is fixed between the piston mechanism and the partition plate and is penetrated by a first oil inlet pipe.

[0006] The protection mechanism comprises a connecting piece arranged at the lower side of the piston mechanism, a cross-shaped support plate is fixedly connected to the bottom end of the connecting piece, and a protection piece for safety limiting is arranged on the cross-shaped support plate.

[0007] The protective member includes a sliding sleeve slidably connected to the lower surface of the four support rods of the cross-shaped support plate, the upper surface of the sliding sleeve is fixedly connected to a fixing box, the interior of the fixing box is slidably connected to a third piston along the direction of the support rods of the cross-shaped support plate, one end of the third piston away from the fixing box penetrates to the outside of the fixing box and is fixedly connected to a rubber extrusion block, and the upper surface of the fixing box is hinged with a diagonal support plate.

[0008] According to an embodiment of the present invention, the piston mechanism includes a second piston which is slidably connected to the circumferential surface of the cylinder body up and down, a second cavity is arranged at the axial position of the second piston, a plurality of sealing gaskets are evenly clamped on the outer circumferential surface of the second piston in the up and down directions, a plurality of first cavities are evenly distributed circumferentially at the positions of the sealing gaskets inside the second piston, the first cavity and the second cavity are connected, the first cavity is slidably connected to the inside of the first cavity and penetrates through the first piston, the end of the first piston away from the first cavity abuts against the inner circumferential surface of the sealing gasket, and the top end of the diagonal support plate is hinged to the lower surface of the second piston.

[0009] According to an embodiment of the present invention, the connecting member includes a plurality of circumferentially evenly distributed telescopic connecting rods fixedly connected to the lower surface of the piston mechanism, the bottom ends of the plurality of telescopic connecting rods are fixedly connected to the cross-shaped support plate, the upper surface of the cross-shaped support plate is fixedly connected to a diverter box, the four vertical surfaces of the diverter box are fixedly and penetrated with a second oil pipe, one end of the second oil pipe away from the diverter box is fixedly and penetrated with a fixed box, and the upper surface of the diverter box is fixedly and penetrated with a telescopic connecting pipe.

[0010] According to an embodiment of the present invention, the conveying mechanism includes a winding piece arranged on the inner wall of the bottom end of the cylinder body, a first oil pipe is wound on the winding piece, a horizontally arranged auxiliary roller is rotatably connected above the winding piece on the inner circumferential surface of the cylinder body, and a scraper sleeve is fixedly connected at the center position of the upper surface of the partition plate.

[0011] According to an embodiment of the present invention, the winding member includes a connecting box rotatably connected to the inner wall of the bottom end of the cylinder body, a spiral spring is arranged between the connecting box and the cylinder body, a winding column is fixedly connected to the upper surface of the connecting box, and the bottom end of the connecting box is rotatably connected to a second oil inlet pipe, which passes through the bottom end of the cylinder body and is fixedly connected to the cylinder body.

[0012] According to an embodiment of the present invention, the bottom end of the first oil pipe is fixed to and connected with the upper surface of the connecting box, the top end of the first oil pipe bypasses the auxiliary roller, passes through the scraper sleeve and penetrates to the upper surface of the partition plate, and the top end of the first oil pipe is slidably connected to the scraper sleeve.

[0013] According to an embodiment of the present invention, the top end of the push rod is provided with a connecting tube connected to the freight elevator. The top end of the push rod penetrates into the upper surface of the cylinder body and is slidably connected to the upper surface of the cylinder body up and down. A seal is provided between the circumferential surface of the push rod and the upper surface of the cylinder body.

[0014] According to an embodiment of the present invention, the partition plate is fixedly connected to the inner circumference of the cylinder body, and the partition plate separates the piston mechanism and the protection mechanism and the conveying mechanism into two areas. The lower surface of the cylinder body is provided with a support seat for generating a supporting force for the cylinder body on the ground.

[0015] Technical solution of the present invention: 1. Through the setting of the protection mechanism, secondary safety limit can be performed during the operation of the hydraulic oil pump. When an accident occurs in the hydraulic oil pump and the hydraulic support force disappears, the protection mechanism can provide secondary support to the push rod to reduce the harm caused by the accident and reduce the risk of rapid fall of the freight elevator.

[0016] 2. By setting the piston mechanism, when the push rod is subjected to a large pressure, the sealing gasket can be prevented from being deformed too much, so that the sealing effect between the second piston and the cylinder body changes as little as possible, thereby ensuring the normal operation of the hydraulic cylinder under high pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0018] Figure 1 It is one of the three-dimensional structural schematic diagrams of the hydraulic cylinder for the hydraulic freight elevator provided by the present invention.

[0019] Figure 2 This is the second three-dimensional structural schematic diagram of the hydraulic cylinder for the hydraulic freight elevator provided by the present invention.

[0020] Figure 3 It is one of the three-dimensional structural schematic diagrams of the piston mechanism provided by the present invention.

[0021] Figure 4 This is the second three-dimensional structural schematic diagram of the piston mechanism provided by the present invention.

[0022] Figure 5 It is a front cross-sectional view of the protection mechanism and the conveying mechanism provided by the present invention.

[0023] Figure 6 The present invention provides Figure 5 Enlarged view of part A.

[0024] Figure 7 The present invention provides Figure 5 Magnified view of part B.

[0025] Figure 8It is a schematic diagram of the three-dimensional structure of the connecting piece provided by the present invention.

[0026] Fig. 9 It is a schematic diagram of the three-dimensional structure of the protective element provided by the present invention.

[0027] Fig.10 This is one of the three-dimensional structural schematic diagrams of the winding piece provided by the present invention.

[0028] Fig.11 This is the second schematic diagram of the three-dimensional structure of the winding piece provided by the present invention.

[0029] 1. Push rod; 2. First oil inlet pipe; 3. Cylinder; 4. Piston mechanism; 5. Protection mechanism; 6. Partition plate; 7. Conveying mechanism; 41. First piston; 42. First cavity; 43. Sealing pad; 44. Second piston; 45. Second cavity; 51. Connecting piece; 52. Protection piece; 53. Cross-shaped supporting plate; 71. Auxiliary roller; 72. Winding piece; 73. First oil pipeline; 74. Scraping sleeve; 511. Telescopic connecting rod; 512. Telescopic connecting pipe; 513. Diverter box; 514. Second oil pipeline; 521. Diagonal support plate; 522. Fixed box; 523. Third piston; 524. Rubber extrusion block; 525. Sliding sleeve; 721. Winding column; 722. Connecting box; 723. Second oil inlet pipe. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0031] like Figure 1 and Figure 2 As shown, a hydraulic cylinder for a hydraulic freight elevator comprises a cylinder body 3, wherein the interior of the cylinder body 3 is provided with a piston mechanism 4, a protection mechanism 5, a partition plate 6 and a conveying mechanism 7 in sequence from top to bottom, a push rod 1 is fixedly connected to the upper surface of the piston mechanism 4, an outer circumferential surface of the cylinder body 3 is located between the piston mechanism 4 and the partition plate 6 and is fixedly connected and penetrated with a first oil inlet pipe 2, a connecting tube connected to the freight elevator is provided at the top end of the push rod 1, the top end of the push rod 1 penetrates to the upper surface of the cylinder body 3 and is slidably connected to the upper surface of the cylinder body 3 up and down, a sealing arrangement is provided between the circumferential surface of the push rod 1 and the upper surface of the cylinder body 3, the partition plate 6 is fixedly connected to the inner circumferential surface of the cylinder body 3, the partition plate 6 divides the piston mechanism 4 and the protection mechanism 5 and the conveying mechanism 7 into two areas, and a support seat for generating a supporting force for the cylinder body 3 on the ground is provided on the lower surface of the cylinder body 3.

[0032] like Figure 1 , Figure 3 and Figure 4 As shown, the piston mechanism 4 includes a second piston 44 which is slidably connected to the inner circumferential surface of the cylinder body 3, a second cavity 45 is provided at the axial position of the second piston 44, a plurality of sealing pads 43 are evenly clamped on the outer circumferential surface of the second piston 44 in the up and down directions, a plurality of first cavities 42 are evenly distributed in a circle at the positions of the sealing pads 43 inside the second piston 44, the first cavity 42 and the second cavity 45 are in a communicating state, a first piston 41 is slidably connected to the inside of the first cavity 42 and penetrates through it, an end of the first piston 41 away from the first cavity 42 abuts against the inner circumferential surface of the sealing pad 43, and the top end of the diagonal support plate 521 is hinged to the lower surface of the second piston 44.

[0033] During specific use, when the freight elevator is lifted by the hydraulic cylinder, the external oil pump is connected to the first oil inlet pipe 2, and hydraulic oil is pumped into the cylinder body 3. The second piston 44 cooperates with the sealing gasket 43 to seal the cylinder body 3. As the hydraulic oil is continuously pumped into the bottom of the second piston 44 and the partition plate 6, the second piston 44 is pushed to move upward inside the cylinder body 3, and the push rod 1 is pushed toward the outside of the cylinder body 3. The top of the push rod 1 is connected to the freight elevator to push the freight elevator upward. When it moves to the specified position, the external oil pump stops pumping oil into the cylinder body 3. The hydraulic oil pump pumps oil into the second cavity 45 through the delivery mechanism 7. As the hydraulic oil continuously enters the second cavity 45, it enters the first cavities 42 through the second cavity 45. As the pressure of the hydraulic oil gradually increases, a thrust is generated on the first piston 41 away from the axis of the second piston 44. The sealing gasket 43 is pushed against the inner wall of the cylinder body 3 by the first piston 41 to prevent the sealing gasket 43 from deforming when the second piston 44 is under relatively large pressure, resulting in reduced sealing between the second piston 44 and the cylinder body 3.

[0034] like Figure 1 and Figure 5 As shown, the protection mechanism 5 includes a connecting member 51 arranged at the lower side of the piston mechanism 4, and a cross-shaped support plate 53 is fixedly connected to the bottom end of the connecting member 51, and a protection member 52 for safety limiting is arranged on the cross-shaped support plate 53.

[0035] like Figure 5 , Figure 6 and Figure 8As shown, the connecting member 51 includes a plurality of circumferentially evenly distributed telescopic connecting rods 511 fixedly connected to the lower surface of the second piston 44, the bottom ends of the plurality of telescopic connecting rods 511 are fixedly connected to the cross-shaped support plate 53, the upper surface of the cross-shaped support plate 53 is fixedly connected to a diverter box 513, the four vertical surfaces of the diverter box 513 are fixedly and penetrated with a second oil pipeline 514, one end of the second oil pipeline 514 away from the diverter box 513 is fixedly and penetrated with a fixed box 522, and the upper surface of the diverter box 513 is fixedly and penetrated with a telescopic connecting pipe 512.

[0036] like Figure 1 and Figure 5 As shown, the conveying mechanism 7 includes a winding piece 72 arranged on the inner wall of the bottom end of the cylinder body 3, and a first oil delivery pipe 73 is wound on the winding piece 72. A horizontally arranged auxiliary roller 71 is rotatably connected above the winding piece 72 on the inner circumferential surface of the cylinder body 3, and a scraper sleeve 74 is fixedly connected at the center position of the upper surface of the partition plate 6.

[0037] like Figure 5 , Fig.10 and Fig.11 As shown, the winding member 72 includes a connecting box 722 rotatably connected to the inner wall of the bottom end of the cylinder body 3, a spiral spring (not shown in the figure) is arranged between the connecting box 722 and the cylinder body 3, a winding column 721 is fixedly connected to the upper surface of the connecting box 722, and the bottom end of the connecting box 722 is rotatably connected to the second oil inlet pipe 723, and the second oil inlet pipe 723 passes through the bottom end of the cylinder body 3 and is fixedly connected to the cylinder body 3.

[0038] like Figure 5 , Fig.10 and Fig.11 As shown, the bottom end of the first oil pipe 73 is fixed and connected with the upper surface of the connecting box 722, the top end of the first oil pipe 73 bypasses the auxiliary roller 71 and passes through the scraper sleeve 74 to the upper surface of the partition plate 6, the top end of the first oil pipe 73 is slidably connected with the scraper sleeve 74, the top end of the first oil pipe 73 passes through the partition plate 6 and then passes through the cross support plate 53 again and is fixed and connected with the lower surface of the diverter box 513, the top end of the telescopic connecting pipe 512 is fixed and connected with the lower surface of the second piston 44, and is in a connected state with the second cavity 45.

[0039] In specific use, when the external hydraulic oil pump pumps oil into the second cavity 45 through the delivery mechanism 7, the external hydraulic oil pump is connected to the second oil inlet pipe 723, and the hydraulic oil is delivered to the inside of the connection box 722 through the second oil inlet pipe 723, and then enters the inside of the first oil delivery pipe 73 from the connection box 722, and the hydraulic oil is delivered to the inside of the diverter box 513 through the first oil delivery pipe 73, and the diverter box 513 delivers the hydraulic oil to the inside of the protective member 52 through the second oil delivery pipe 514, and at the same time delivers the hydraulic oil to the inside of the second cavity 45 through the telescopic connection pipe 512.

[0040] When the second piston 44 moves upward, the second piston 44 pulls the cross-shaped support plate 53 upward through the telescopic connecting rod 511, and the cross-shaped support plate 53 pulls the first oil pipe 73 upward. At this time, the first oil pipe 73 is separated from the winding column 721 and gradually moves upward, and drives the connecting box 722 to rotate at the bottom end of the cylinder body 3 to shrink the spiral spring. At the same time, the first oil pipe 73 passes through the auxiliary roller 71, and the auxiliary roller 71 rotates on the cylinder body 3 to enable the first oil pipe 73 to move upward smoothly. When the second piston 44 is retracted, the first oil pipe 73 is no longer subjected to tension. At this time, under the action of the elastic force of the spiral spring itself, the connecting box 722 is driven to reverse and retract the first oil pipe 73 to the winding column 721 again. When the first oil pipe 73 is retracted and passes through the scraper sleeve 74, the scraper sleeve 74 can scrape off the hydraulic oil adhering to the outer wall of the first oil pipe 73 to prevent the hydraulic oil from adhering to the outer wall of the first oil pipe 73.

[0041] like Figure 5 , Figure 7 and Fig. 9 As shown, the protective member 52 includes a sleeve 525 slidably connected to the lower surface of the four support rods of the cross-shaped support plate 53, the upper surface of the sleeve 525 is fixedly connected to a fixed box 522, the interior of the fixed box 522 is slidably connected to a third piston 523 along the direction of the support rods of the cross-shaped support plate 53, the end of the third piston 523 away from the fixed box 522 penetrates to the outside of the fixed box 522 and is fixedly connected to a rubber extrusion block 524, and the upper surface of the fixed box 522 is hinged with a diagonal support plate 521.

[0042] During actual use, when the hydraulic oil is delivered to the interior of the protective member 52, the hydraulic oil enters the interior of the fixed box 522 through the second oil pipe 514. As the hydraulic oil continues to enter, a thrust is generated on the third piston 523 away from the second oil pipe 514, pushing the rubber extrusion block 524 against the inner wall of the cylinder body 3.

[0043] When an unexpected situation occurs when the second piston 44 lifts the freight elevator through the push rod 1, the second piston 44 loses its supporting force and slides downward. At this time, the second piston 44 moves downward rapidly, and the second piston 44 generates a thrust on the fixed box 522 through the diagonal support plate 521. At this time, the rubber extrusion block 524 is pressed against the inside of the cylinder body 3, and the second piston 44 pushes the telescopic connecting rod 511 to contract. When the second piston 44 falls at a high speed, the second piston 44 forms a triangular supporting area between the diagonal support plate 521 and the third piston 523. The rubber extrusion block 524 is subjected to the thrust from the second piston 44, and the pressure of the hydraulic oil makes the rubber extrusion block 524 press against the inner wall of the cylinder body 3 to cushion the second piston 44 in the process of falling downward. In the event of an unexpected situation, the damage caused by the unexpected situation is reduced as much as possible.

[0044] Working principle: During specific use, when the freight elevator is lifted by the hydraulic cylinder, the external oil pump is connected to the first oil inlet pipe 2, and hydraulic oil is pumped into the interior of the cylinder body 3 to push the piston mechanism 4 to move upward inside the cylinder body 3, and the push rod 1 is pushed toward the outside of the cylinder body 3. The top of the push rod 1 is connected to the freight elevator to push the freight elevator upward. When it moves to the specified position, the external oil pump pumps oil to the interior of the protective part 52 through the conveying mechanism 7, and the protective part 52 is supported on the inner wall of the cylinder body 3 to generate a secondary safety limit for the piston mechanism 4. When an unexpected situation occurs, the piston mechanism 4 loses its supporting force and slides downward rapidly. The piston mechanism 4 is limited by the protective part 52 to prevent the piston mechanism 4 from falling at a rapid speed.

[0045] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0046] In addition, the terms "first", "second", "number one", "number two" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second", "number one", "number two" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0047] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] The embodiments of this specific implementation method are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A hydraulic cylinder for a hydraulic freight elevator, characterized in that: The invention comprises a cylinder body (3), wherein a piston mechanism (4), a protection mechanism (5), a partition plate (6) and a conveying mechanism (7) are arranged in sequence from top to bottom inside the cylinder body (3); a push rod (1) is fixedly connected to the upper surface of the piston mechanism (4); and a first oil inlet pipe (2) is fixedly connected and penetrated by the outer circumferential surface of the cylinder body (3) between the piston mechanism (4) and the partition plate (6); The protection mechanism (5) comprises a connecting member (51) arranged at the lower side of the piston mechanism (4), the bottom end of the connecting member (51) is fixedly connected to a cross-shaped support plate (53), and a protection member (52) for safety limiting is arranged on the cross-shaped support plate (53); The protective member (52) comprises a sliding sleeve (525) slidably connected to the lower surface of four support rods of the cross-shaped support plate (53); a fixing box (522) is fixedly connected to the upper surface of the sliding sleeve (525); a third piston (523) is slidably connected to the interior of the fixing box (522) along the direction of the support rods of the cross-shaped support plate (53); an end of the third piston (523) away from the fixing box (522) penetrates to the outside of the fixing box (522) and is fixedly connected to a rubber extrusion block (524); and a diagonal support plate (521) is hingedly connected to the upper surface of the fixing box (522).

2. A hydraulic cylinder for a hydraulic freight elevator according to claim 1, characterized in that: The piston mechanism (4) comprises a second piston (44) connected to the inner circumferential surface of the cylinder body (3) in a sliding manner up and down, a second cavity (45) is arranged at the axial position of the second piston (44), a plurality of sealing pads (43) are evenly clamped on the outer circumferential surface of the second piston (44) in the up and down directions, a plurality of first cavities (42) are evenly distributed in a circumferential manner at the positions of the sealing pads (43) inside the second piston (44), the first cavity (42) and the second cavity (45) are in a communicating state, a first piston (41) is connected to the inside of the first cavity (42) in a sliding manner and penetrates through the first cavity (42), an end of the first piston (41) away from the first cavity (42) abuts against the inner circumferential surface of the sealing pad (43), and the top end of the diagonal support plate (521) is hinged to the lower surface of the second piston (44).

3. The hydraulic cylinder for a hydraulic freight elevator according to claim 1, characterized in that: The connecting member (51) comprises a plurality of circumferentially evenly distributed telescopic connecting rods (511) fixedly connected to the lower surface of the piston mechanism (4); the bottom ends of the plurality of telescopic connecting rods (511) are fixedly connected to the cross-shaped support plate (53); a diverter box (513) is fixedly connected to the upper surface of the cross-shaped support plate (53); a second oil delivery pipe (514) is fixedly connected and penetrated on four vertical surfaces of the diverter box (513); an end of the second oil delivery pipe (514) away from the diverter box (513) is fixedly connected and penetrated with a fixing box (522); and a telescopic connecting pipe (512) is fixedly connected and penetrated on the upper surface of the diverter box (513).

4. The hydraulic cylinder for a hydraulic freight elevator according to claim 1, characterized in that: The conveying mechanism (7) comprises a winding member (72) arranged on the inner wall of the bottom end of the cylinder body (3), a first oil delivery pipe (73) is wound around the winding member (72), a horizontally arranged auxiliary roller (71) is rotatably connected above the winding member (72) on the inner circumferential surface of the cylinder body (3), and a scraper sleeve (74) is fixedly connected at the center position of the upper surface of the partition plate (6).

5. The hydraulic cylinder for a hydraulic freight elevator according to claim 4, characterized in that: The winding member (72) comprises a connecting box (722) rotatably connected to the inner wall of the bottom end of the cylinder body (3); a spiral spring is provided between the connecting box (722) and the cylinder body (3); a winding column (721) is fixedly connected to the upper surface of the connecting box (722); the bottom end of the connecting box (722) is rotatably connected to a second oil inlet pipe (723); the second oil inlet pipe (723) passes through the bottom end of the cylinder body (3) and is fixedly connected to the cylinder body (3).

6. A hydraulic cylinder for a hydraulic freight elevator according to claim 5, characterized in that: The bottom end of the first oil delivery pipe (73) is fixed to and connected with the upper surface of the connection box (722), the top end of the first oil delivery pipe (73) bypasses the auxiliary roller (71), passes through the scraper sleeve (74) and penetrates to the upper surface of the partition plate (6), and the top end of the first oil delivery pipe (73) is slidably connected with the scraper sleeve (74).

7. The hydraulic cylinder for a hydraulic freight elevator according to claim 1, characterized in that: The top end of the push rod (1) is provided with a connecting tube connected to the freight elevator. The top end of the push rod (1) penetrates the upper surface of the cylinder body (3) and is connected to the upper surface of the cylinder body (3) by sliding up and down. The circumferential surface of the push rod (1) and the upper surface of the cylinder body (3) are sealed.

8. The hydraulic cylinder for a hydraulic freight elevator according to claim 1, characterized in that: The partition plate (6) is fixedly connected to the inner circumferential surface of the cylinder body (3), and the partition plate (6) divides the piston mechanism (4) and the protection mechanism (5) and the conveying mechanism (7) into two areas. The lower surface of the cylinder body (3) is provided with a support seat for generating a supporting force for the cylinder body (3) on the ground.

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