CN115750486A - Platform leveling system, aerial work platform and aerial work machine - Google Patents

Abstract

The invention discloses a platform leveling system, an aerial work platform and an aerial work machine, wherein the platform leveling system comprises a rotary table, an arm frame assembly, a work platform and a leveling loop, the arm frame assembly comprises a first arm frame and a second arm frame which are hinged, the first arm frame is hinged with the work platform, the second arm frame is hinged with the rotary table, the leveling loop comprises a first leveling oil cylinder, a second leveling oil cylinder and a third leveling oil cylinder, two ends of the first leveling oil cylinder are respectively hinged with the first arm frame and the work platform, two ends of the second leveling oil cylinder are respectively hinged with the first arm frame and the second arm frame, two ends of the third leveling oil cylinder are respectively hinged with the second arm frame and the rotary table, rod cavities of the first leveling oil cylinder, the second leveling oil cylinder and the third leveling oil cylinder are connected to form a closed oil path, rod-free cavities of the first leveling oil cylinder, the second leveling oil cylinder and the third leveling oil cylinder are connected to form a closed oil path, and the specifications of the first leveling oil cylinder, the second leveling oil cylinder and the third leveling oil cylinder are the same. The leveling angle of the platform is ensured to be accurately matched with the amplitude change of the arm support.

Description

Platform leveling system, aerial work platform and aerial work machine

Technical Field

The invention relates to a hydraulic leveling mechanism, in particular to a platform leveling system. In addition, the aerial work platform and the aerial work machine are also related.

Background

The aerial work machine is generally provided with a manned working platform or a functional accessory, and the manned working platform or the functional accessory is always required to be level with the ground along with the amplitude variation of the arm support during operation, or the angle of the manned working platform or the functional accessory relative to the ground is always kept unchanged no matter how the angle of the arm support changes. This requires a leveling mechanism or system that can follow the angle of the manned work platform or functional accessories according to the change of the angle of the arm support.

The angle adjustment of the manned working platform can adopt a manual or automatic mode, the efficiency of manual angle adjustment is low, and the manual angle adjustment is generally used for setting the initial angle of the manned working platform or eliminating the angle error; the angle of the manned working platform is automatically adjusted along with the amplitude of the arm support, so that on one hand, the automatic angle adjustment efficiency is high, on the other hand, the manual error can be effectively avoided, and the falling accidents of personnel and articles can be prevented from occurring from the operation aspect to the maximum extent.

For the aerial work platform with the hybrid arm structure moving in the forward direction and the reverse direction, the manned work platform usually adopts an electro-hydraulic leveling mode due to structural characteristics, but the electro-hydraulic leveling mode has higher cost and energy consumption, more fault points and poorer reliability compared with a mechanical-hydraulic leveling mode.

Therefore, there is a need to design a platform leveling system to overcome or alleviate the above technical problems.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a platform leveling system which has the advantages of low cost and energy consumption, few fault points and good reliability, and ensures that the leveling angle of the platform is accurately matched with the amplitude change of an arm support.

The invention further aims to solve the technical problem that the aerial work platform can ensure that the leveling angle of the platform is accurately matched with the amplitude change of the arm support.

The invention also aims to solve the technical problem that the aerial work platform of the aerial work machine has better leveling safety.

In order to solve the technical problems, a first aspect of the invention provides a platform leveling system, which comprises a rotary table, an arm frame assembly, a working platform and a leveling loop, wherein the arm frame assembly comprises a first arm frame and a second arm frame which are hinged, the first arm frame is hinged with the working platform, the second arm frame is hinged with the rotary table, the leveling loop comprises a first leveling cylinder, a second leveling cylinder and a third leveling cylinder, two ends of the first leveling cylinder are respectively hinged with the first arm frame and the working platform, two ends of the second leveling cylinder are respectively hinged with the first arm frame and the second arm frame, two ends of the third leveling cylinder are respectively hinged with the second arm frame and the rotary table, rod cavities of the first leveling cylinder, the second leveling cylinder and the third leveling cylinder are connected to form a closed oil path, rod-free cavities of the first leveling cylinder, the second leveling cylinder and the third leveling cylinder are connected to form a closed oil path, and the specifications of the first leveling cylinder, the second leveling cylinder and the third cylinder are the same.

In some embodiments, a first end of the first arm support is hinged to the working platform through a first hinge point, a first end of the first leveling cylinder is hinged to the working platform through a second hinge point, a second end of the first leveling cylinder is hinged to the first end of the first arm support through a third hinge point, a second end of the first arm support is hinged to the first end of the second arm support through a fourth hinge point, a first end of the second leveling cylinder is hinged to the second end of the first arm support through a fifth hinge point, a second end of the second leveling cylinder is hinged to the first end of the second arm support through a sixth hinge point, a second end of the second arm support is hinged to the turntable through a seventh hinge point, a first end of the third leveling cylinder is hinged to the second end of the second arm support through an eighth hinge point, and a second end of the third leveling cylinder is hinged to the turntable through a ninth hinge point; when the first leveling cylinder, the second leveling cylinder and the third leveling cylinder are all in a fully extended or fully retracted state, the triangle formed by the first hinge point, the second hinge point and the third hinge point, the triangle formed by the fourth hinge point, the fifth hinge point and the sixth hinge point, and the triangle formed by the seventh hinge point, the eighth hinge point and the ninth hinge point are equal.

In some embodiments, the seventh hinge point is located between the fourth hinge point and the eighth hinge point.

In some embodiments, a first luffing oil cylinder is installed between the first boom and the second boom, a second luffing oil cylinder is installed between the second boom and the rotary table, the first luffing oil cylinder and the second luffing oil cylinder are both connected with the multi-way valve, and a second boom luffing safety limiting oil path is arranged between a rod chamber and a non-rod chamber of the second luffing oil cylinder.

In some embodiments, the second boom amplitude safety limiting oil path comprises a first limiting oil path connected between a rod chamber and a rodless chamber of the second amplitude oil cylinder, the first limiting oil path is provided with a motorized reversing valve and a first one-way valve capable of guiding oil in the rod chamber of the second amplitude oil cylinder to an oil path connected with the rodless chamber in a single direction, and a control end of the motorized reversing valve is arranged opposite to the first boom.

In some embodiments, the second boom variable-amplitude safety limiting oil path comprises a second limiting oil path connected between the rod cavity of the second variable-amplitude oil cylinder and the rodless cavity thereof, and the second limiting oil path is provided with a first electromagnetic reversing valve and a second one-way valve capable of guiding oil in the rod cavity of the second variable-amplitude oil cylinder to the oil path connected with the rodless cavity thereof in a single direction.

In some embodiments, a first boom amplitude-variable safety limiting oil way is arranged between the rod cavity of the first amplitude-variable oil cylinder and the rodless cavity of the first amplitude-variable oil cylinder.

In some embodiments, a second electromagnetic directional valve and a third one-way valve capable of guiding oil in the rodless cavity of the first luffing oil cylinder to the rod cavity thereof in a single direction are arranged on the first boom luffing safety limiting oil path.

In some embodiments, a first balance valve is arranged between the first luffing cylinder and the multi-way valve, and a second balance valve is arranged between the second luffing cylinder and the multi-way valve.

In some embodiments, a one-way stop reversing valve is connected to the oil inlet of the multi-way valve.

In some embodiments, the leveling circuit further comprises a direction valve and a holding valve, the direction valve being connected to the third leveling cylinder through the holding valve.

In some embodiments, a third balancing valve is disposed between the first leveling cylinder and the second leveling cylinder.

A second aspect of the invention provides an aerial work platform provided with a platform leveling system according to any one of the above technical solutions.

The invention provides an aerial work machine in a third aspect, which is provided with the aerial work platform in the technical scheme.

Through the technical scheme, the invention has the following beneficial effects:

the first leveling cylinder, the second leveling cylinder and the third leveling cylinder are connected with rod cavities to form a closed oil path, the three rodless cavities are connected to form a closed oil path, and the first leveling cylinder, the second leveling cylinder and the third leveling cylinder which have the same specification are adopted, so that the variation of the extending length and the retracting length of the first leveling cylinder, the second leveling cylinder and the third leveling cylinder during linkage is ensured to be completely equal, and the leveling angle of the working platform is ensured to be accurately matched with the amplitude change of the arm support. The platform leveling system provided by the invention belongs to a mechanical hydraulic leveling system, avoids complex hydraulic and electric control loops of an electro-hydraulic leveling system, and has the advantages of few fault points and high reliability.

Further, the distances between the hinge points of the first leveling cylinder, the second leveling cylinder and the third leveling cylinder and the hinge points of the first arm support, the second arm support and the rotary table are reasonably set, so that when the first leveling cylinder, the second leveling cylinder and the third leveling cylinder are in a fully extended or fully retracted state, a triangle formed by the first hinge point, the second hinge point and the third hinge point, a triangle formed by the fourth hinge point, the fifth hinge point and the sixth hinge point, a triangle formed by the seventh hinge point, an eighth hinge point and a ninth hinge point are equal, the variation of the extension and retraction lengths of the first leveling cylinder, the second leveling cylinder and the third leveling cylinder in linkage is ensured to be completely equal, and the leveling angle of the working platform is ensured to be accurately matched with the amplitude variation of the arm support.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is one of the schematic structural views of a platform leveling system disclosed in an embodiment of the present invention;

FIG. 2 is a second schematic structural view of a platform leveling system according to an embodiment of the present invention;

FIG. 3 is a third schematic structural view of a platform leveling system according to an embodiment of the present invention;

FIG. 4 is a fourth schematic structural view of a platform leveling system according to the present invention;

FIG. 5 is a hydraulic schematic diagram of a platform leveling system as disclosed in a first embodiment of the present invention;

fig. 6 is a hydraulic schematic diagram of a platform leveling system according to a second embodiment of the present invention.

Description of the reference numerals

1 turntable and 2 working platform

31 first arm support 32 second arm support

41 first leveling cylinder 42 second leveling cylinder

43 first hinge point of third leveling cylinder A

B second hinge point C third hinge point

D fourth hinge point E fifth hinge point

F sixth hinge point G seventh hinge point

H eighth hinge point I ninth hinge point

51 first luffing cylinder 52 second luffing cylinder

6 multi-way valve 71 motor-driven reversing valve

72 first check valve 73 first electromagnetic directional valve

74 second check valve 75 second electromagnetic directional valve

76 third check valve 77 first counter balance valve

78 second balance valve 79 one-way stop reversing valve

81 change valve 82 holding valve

83 third balance valve

Detailed Description

The embodiments of the present invention will be described in further detail with reference to the drawings and examples. The following detailed description of the embodiments and the accompanying drawings are included to illustrate the principles of the invention and are not intended to limit the scope of the invention, which may be embodied in many different forms and not limited to the specific embodiments disclosed herein, but include all technical solutions falling within the scope of the claims.

It is to be understood that in the description of the present invention, unless otherwise specified, the terms indicating orientation or positional relationship are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention. When the absolute position of the object being described changes, then the relative positional relationship may also change accordingly.

Moreover, the use of "first," "second," "third," "fourth," "fifth," "sixth," "seventh," "eighth," "ninth," and similar words in the present disclosure does not denote any order, quantity, or importance, but rather the words are used to distinguish one element from another. "parallel" is not strictly parallel but is within the tolerance of the error. The word "comprising" or "comprises", and the like, means that the element preceding the word covers the element listed after the word, and does not exclude the possibility that other elements are also covered.

It should also be noted that, unless expressly specified or limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly and encompass, for example, both fixed and removable connections or integral connections; may be directly connected or indirectly connected through an intermediate. The specific meaning of the above terms in the present invention can be understood as appropriate to those of ordinary skill in the art. When a particular device is described as being between a first device and a second device, intervening devices may or may not be present between the particular device and the first device or the second device.

All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise specifically defined. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate.

As shown in fig. 1 to 4, the present invention provides a platform leveling system, which includes a turntable 1, an arm support assembly, a work platform 2, and a leveling loop, wherein the arm support assembly includes a first arm support 31 and a second arm support 32, the first arm support 31 is hinged to the work platform 2, the second arm support 32 is hinged to the turntable 1, the leveling loop includes a first leveling cylinder 41, a second leveling cylinder 42, and a third leveling cylinder 43, one end of the first leveling cylinder 41 is hinged to the first arm support 31, the other end of the first leveling cylinder is hinged to the work platform 2, one end of the second leveling cylinder 42 is hinged to the first arm support 31, the other end of the second leveling cylinder is hinged to the second arm support 32, one end of the third leveling cylinder 43 is hinged to the second arm support 32, the other end of the third leveling cylinder is hinged to the turntable 1, the first leveling cylinder 41, the second leveling cylinder 42, and the third leveling cylinder 43 are connected in parallel, a rod cavity of the first leveling cylinder 41, a rod cavity of the second leveling cylinder 42 and a closed leveling cylinder 43 are formed by a closed oil path, and a closed leveling cylinder 43 without a rod cavity of the leveling cylinder 41 and a leveling cylinder 43. Therefore, when the first leveling cylinder 41, the second leveling cylinder 42 and the third leveling cylinder 43 are linked, the extension and retraction length variation of the first leveling cylinder 41, the second leveling cylinder 42 and the third leveling cylinder 43 are completely equal, so that the leveling angle of the working platform 2 can be accurately matched with the amplitude variation of the arm support.

It should be noted that, for convenience of understanding, directions of the boom and the oil cylinder are defined, where, as shown in fig. 4, in a state where the first boom 31 and the second boom 32 are lifted in an amplitude-varying manner, the first end refers to an end of the boom and the oil cylinder close to the working platform 2, and the second end refers to an end of the boom and the oil cylinder close to the turntable 1.

In some embodiments, a first end of the first arm rest 31 is hinged to the working platform 2 through a first hinge point a, a first end of the first leveling cylinder 41 is hinged to the working platform 2 through a second hinge point B, a second end of the first leveling cylinder 41 is hinged to the first end of the first arm rest 31 through a third hinge point C, a second end of the first arm rest 31 is hinged to the first end of the second arm rest 32 through a fourth hinge point D, a first end of the second leveling cylinder 42 is hinged to the second end of the first arm rest 31 through a fifth hinge point E, a second end of the second leveling cylinder 42 is hinged to the first end of the second arm rest 32 through a sixth hinge point F, a second end of the second arm rest 32 is hinged to the turntable 1 through a seventh hinge point G, a first end of the third leveling cylinder 43 is hinged to the second end of the second arm rest 32 through an eighth hinge point H, and a second end of the third leveling cylinder 43 is hinged to the turntable 1 through a ninth hinge point I; when the first leveling cylinder 41, the second leveling cylinder 42 and the third leveling cylinder 43 are all in a fully extended or fully retracted state, a triangle formed by the first hinge point a, the second hinge point B and the third hinge point C, a triangle formed by the fourth hinge point D, the fifth hinge point E and the sixth hinge point F, a triangle formed by the seventh hinge point G, the eighth hinge point H and the ninth hinge point I are all equal.

When the first leveling cylinder 41, the second leveling cylinder 42 and the third leveling cylinder 43 are linked, the extension and retraction length variation amounts of the first leveling cylinder 41, the second leveling cylinder 42 and the third leveling cylinder 43 are completely equal, so that the leveling angle of the working platform 2 can be accurately matched with the amplitude variation of the arm support. Moreover, the platform leveling system belongs to a mechanical hydraulic leveling system, avoids complex hydraulic and electric control loops of an electro-hydraulic leveling system, and has few fault points and high reliability.

Generally, the oil cylinder and the arm support can be hinged by arranging a pin, that is, the hinge can be realized by arranging a pin between the working platform 2 and the first arm support 31, between the first leveling oil cylinder 41 and the working platform 2 and the first arm support 31, between the first arm support 31 and the second arm support 32, between the second leveling oil cylinder 42 and the first arm support 31 and the second arm support 32, between the second arm support 32 and the turntable 1, and between the third leveling oil cylinder 43 and the second arm support 32 and the turntable 1.

In some embodiments, referring to fig. 1, a first luffing cylinder 51 is installed between the first boom 31 and the second boom 32, a link mechanism may be disposed between the first luffing cylinder 51 and the first boom 31 and the second boom 32, the first boom 31 is hinged to a first end of the first luffing cylinder 51 through a link, one end of the second boom 32 is hinged to a first end of the first luffing cylinder 51 through a link, a second end of the first luffing cylinder 51 is hinged to another end of the second boom 32, amplitude change of the first boom 31 can be controlled by the first luffing cylinder 51, and when a piston rod of the first luffing cylinder 51 extends, a piston rod of the second leveling cylinder 42 extends therewith; a second luffing cylinder 52 is arranged between the second arm support 32 and the rotary table 1, a first end of the second luffing cylinder 52 is hinged with the second arm support 32, a second end of the second luffing cylinder 52 is hinged with the rotary table 1, and the amplitude change of the second arm support 32 can be controlled through the second luffing cylinder 52.

In some embodiments, referring to fig. 1, the seventh hinge point G is located between the fourth hinge point D and the eighth hinge point H, that is, the eighth hinge point H formed by hinging the first end of the third leveling cylinder 43 and the second end of the second arm support 32 is located at the tail end of the second arm support 32, where the tail end of the second arm support 32 refers to an end region of the second arm support 32 close to the turntable 1, and at this time, the second luffing cylinder 52 and the third leveling cylinder 43 are located at two sides of the turntable 1, so that the movement direction of the piston rod of the first leveling cylinder 41 is opposite to the movement direction of the piston rod of the third leveling cylinder 43, thereby ensuring the leveling accuracy of the platform leveling system structurally, and when the piston rod of the second luffing cylinder 52 extends, the piston rod of the second leveling cylinder 42 retracts. Of course, it is also possible to arrange the eighth hinge point H inside the seventh hinge point G, i.e. the third leveling cylinder 43 is mounted on the same side of the turret 1 as the second luffing cylinder 52.

In some embodiments, referring to fig. 5 and 6, the leveling circuit further includes a reversing valve 81 and a holding valve 82, the reversing valve 81 is connected to the third leveling cylinder 43 through the holding valve 82, the holding valve 82 includes a double hydraulic control check valve and an overflow valve, the overflow valve is connected to the double hydraulic control check valve, two oil outlets of the double hydraulic control check valve are connected to the rod chamber and the rodless chamber of the third leveling cylinder 43 in a one-to-one correspondence manner, so that an oil path formed by connecting the first leveling cylinder 41, the second leveling cylinder 42, and the third leveling cylinder 43 in parallel is a closed oil path, the oil in the closed oil path cannot flow to the reversing valve 81 from the holding valve 82 until a certain pressure is reached, the oil in the closed oil path communicating the rod chambers of the first leveling cylinder 41, the second leveling cylinder 42, and the third leveling cylinder 43 flows in the closed oil path, and the oil in the rodless chamber communicating the first leveling cylinder 41, the second leveling cylinder 42, and the third leveling cylinder 43 flows in the closed oil path. When the oil in the closed oil path formed by the first leveling oil cylinder 41, the second leveling oil cylinder 42 and the third leveling oil cylinder 43 connected in parallel is reduced, the reversing valve 81 can be controlled to reverse, and the oil can be supplemented to the oil paths where the rodless cavities or the rod cavities of the first leveling oil cylinder 41, the second leveling oil cylinder 42 and the third leveling oil cylinder 43 are located.

Further, a third balance valve 83 may be provided between the first and second leveling cylinders 41 and 42 to enable the work platform 2 to smoothly stay at a desired adjustment position.

In some embodiments, the first luffing cylinder 51 is configured to drive the first boom 31 to perform luffing motion, and the second luffing cylinder 52 is configured to drive the second boom 32 to perform luffing motion. The first luffing cylinder 51 and the second luffing cylinder 52 are respectively connected with one of the multi-way valves 6, the working unit comprises a main valve, and the first luffing cylinder 51 or the second luffing cylinder 52 is controlled to execute corresponding actions by reversing the main valve. The oil inlet P of the multi-way valve 6 is connected with a one-way stop reversing valve 79, the one-way stop reversing valve 79 is connected with an oil inlet oil path, and specifically, the one-way stop reversing valve 79 can be a two-position two-way one-way stop electromagnetic valve.

In some embodiments, as shown in fig. 5 and 6, a first balance valve 77 is provided between the first luffing cylinder 51 and the multiplex valve 6 to enable the first boom 31 to smoothly stay at a desired adjustment position, and a second balance valve 78 is provided between the second luffing cylinder 52 and the multiplex valve 6 to enable the second boom 32 to smoothly stay at a desired adjustment position.

A safety limiting oil circuit can be arranged on the hydraulic circuit, and direct guarantee is provided for leveling safety of the working platform from the hydraulic system level.

Referring to fig. 4, when the first boom 31 and the second boom 32 are both in the luffing lifting state, in order to prevent the leveling angle of the working platform 2 from exceeding the safe range, the second boom cannot luffing down, and for this reason, a second boom luffing safe limiting oil path may be provided between the rod chamber of the second luffing oil cylinder 52 and the rod-free chamber of the second luffing oil cylinder 52 to limit the luffing down of the second luffing oil cylinder 52.

In some embodiments, referring to fig. 5, the second boom luffing safety limiting oil circuit comprises a first limiting oil circuit, the first limiting oil circuit is connected between the rod chamber and the rodless chamber of the second luffing cylinder 52, a motorized reversing valve 71 and a first one-way valve 72 are arranged on the first limiting oil circuit, referring to fig. 3, a control end of the motorized reversing valve 71 is arranged opposite to the first boom 31, so that when the first boom 31 is luffably lifted to a certain position, the control end of the motorized reversing valve 71 is touched to reverse the motorized reversing valve 71, so that the oil in the rod chamber of the second luffing cylinder 52 flows unidirectionally to the oil circuit connected to the rodless chamber of the second luffing cylinder 52 through the first one-way valve 72, and further flows back to the oil tank through a main valve in a corresponding working connection in the multi-way valve 6, and unloads the rod chamber oil circuit of the second luffing cylinder 52, and cannot form enough luffing hydraulic pressure to push the piston rod of the second luffing cylinder 52 to retract, that the second luffing cylinder 32 cannot move down the boom. The purpose of limiting the amplitude angle of the second arm support 32 is achieved, so that the first arm support 31 is prevented from tilting backwards due to misoperation.

Or, referring to fig. 6, the limitation of the amplitude reduction of the second boom 32 may also be realized by a solenoid valve control; specifically, the second boom variable amplitude safety limiting oil circuit may also include a second limiting oil circuit, the second limiting oil circuit is connected between the rod chamber and the rodless chamber of the second variable amplitude cylinder 52, the second limiting oil circuit is provided with a first electromagnetic directional valve 73 and a second one-way valve 74, a corresponding position of the first boom 31 is provided with a corresponding element for detecting the variable amplitude state of the first boom 31, such as an angle sensor or a travel switch, and the controller detects an angle signal or a boom variable amplitude position, and when the first boom 31 is raised to a certain position in a variable amplitude manner, the first electromagnetic directional valve 73 is controlled to be switched, so that the oil in the rod chamber of the second variable amplitude cylinder 52 flows to the oil circuit connected to the rodless chamber of the second variable amplitude cylinder 52 through the second one-way valve 74, and then flows back to the oil tank through a corresponding main valve in the working link in the multi-way valve 6, and forms an oil circuit on the rod chamber side of the second variable amplitude cylinder 52, and cannot form a sufficient hydraulic pressure to push the second boom 32 to retract, that the second boom 32 cannot unload downward. The purpose of limiting the amplitude angle of the second arm support 32 is achieved, so that the first arm support 31 is prevented from tilting backwards due to misoperation.

Alternatively, as shown in fig. 6, the first limiting oil path and the second limiting oil path may be provided between the rod chamber and the rodless chamber of the second luffing cylinder 52 to improve the safety of the system.

Referring to fig. 3, in the case that the second luffing cylinder 52 is not operated, in order to prevent excessive upward pitching after exceeding the angle adjustable range of the working platform 2, the luffing angle of the first boom 31 also needs to be limited, that is, angle a in fig. 3 needs to be limited to a safety value, and a first boom luffing safety limiting oil path may be provided between the rod chamber of the first luffing cylinder 51 and the rodless chamber of the first luffing cylinder 51. The angle a is a relative angle between the first arm support 31 and the second arm support 32.

In some embodiments, the second electromagnetic directional valve 75 and the third one-way valve 76 are disposed on the first boom amplitude-variable safety limiting oil path, and when the first boom 31 is amplitude-variable and ascends to a certain position, the second electromagnetic directional valve 75 is controlled to be reversed, so that the oil in the rodless cavity of the first amplitude-variable oil cylinder 51 flows to the oil path connected to the rod cavity of the first amplitude-variable oil cylinder 51 in a single direction through the third one-way valve 76, and then flows back to the oil tank through the corresponding main valve in the working linkage in the multi-way valve 6, the oil path on the rodless cavity side of the first amplitude-variable oil cylinder 51 is unloaded, and sufficient hydraulic pressure cannot be formed to push the piston rod of the first amplitude-variable oil cylinder 51 to extend, that is, the first boom 31 cannot ascend continuously.

For a better understanding of the technical concept of the present invention, the following description is made in conjunction with relatively full technical features.

As shown in fig. 1 to 6, the invention discloses a platform leveling system, which comprises a rotary table 1, an arm support assembly, a leveling loop of a working platform 2, a first luffing cylinder 51 and a second luffing cylinder 52, wherein the arm support assembly comprises a first arm support 31 and a second arm support 32, the leveling loop comprises a first leveling cylinder 41, a second leveling cylinder 42, a third leveling cylinder 43, a reversing valve 81, a holding valve 82 and a third balancing valve 83, a rod cavity of the first leveling cylinder 41, a rod cavity of the second leveling cylinder 42 and a rod cavity of the third leveling cylinder 43 are connected, a rod-free cavity of the first leveling cylinder 41, a rod-free cavity of the second leveling cylinder 42 and a rod-free cavity of the third leveling cylinder 43 are connected, the third leveling cylinder 43 is connected with the holding valve 82, the first leveling cylinder 41, the second leveling cylinder 42 and the third leveling cylinder 43 are connected in parallel to form a closed oil path, the holding valve 82 is connected with the reversing valve 81, the electromagnetic reversing valve 81 can be installed between the first leveling cylinder 41 and the second leveling cylinder 42. A first end of the first arm support 31 is hinged to the working platform 2 through a first hinge point a, a first end of the first leveling cylinder 41 is hinged to the working platform 2 through a second hinge point B, a second end of the first leveling cylinder 41 is hinged to the first end of the first arm support 31 through a third hinge point C, a second end of the first arm support 31 is hinged to the first end of the second arm support 32 through a fourth hinge point D, a first end of the second leveling cylinder 42 is hinged to the second end of the first arm support 31 through a fifth hinge point E, a second end of the second leveling cylinder 42 is hinged to the first end of the second arm support 32 through a sixth hinge point F, a second end of the second arm support 32 is hinged to the turntable 1 through a seventh hinge point G, a first end of the third leveling cylinder 43 is hinged to the second end of the second arm support 32 through an eighth hinge point H, and a second end of the third leveling cylinder 43 is hinged to the turntable 1 through a ninth hinge point I; when the first leveling cylinder 41, the second leveling cylinder 42 and the third leveling cylinder 43 are all in a fully extended or fully retracted state, a triangle formed by the first hinge point a, the second hinge point B and the third hinge point C, a triangle formed by the fourth hinge point D, the fifth hinge point E and the sixth hinge point F, a triangle formed by the seventh hinge point G, the eighth hinge point H and the ninth hinge point I are all equal. The first luffing cylinder 51 is installed between the first boom 31 and the second boom 32 and used for driving the first boom 31 to perform luffing motion, the second luffing cylinder 52 is installed between the second boom 32 and the turntable 1 and used for driving the second boom 32 to perform luffing motion, the second luffing cylinder 52 and the third leveling cylinder 43 are respectively located on two opposite sides of the turntable 1, that is, the eighth hinge point H is arranged outside the seventh hinge point G. A first balance valve 77 is arranged between the first luffing cylinder 51 and the multi-way valve 6, a second balance valve 78 is arranged between the second luffing cylinder 52 and the multi-way valve 6, a one-way stop reversing valve 79 is arranged between an oil inlet P and an oil inlet path of the multi-way valve 6, and an oil return port T of the multi-way valve 6 is connected with an oil return path. A second boom amplitude safety limiting oil way is arranged between the rod cavity of the second amplitude cylinder 52 and the rodless cavity of the second amplitude cylinder 52, the second boom amplitude safety limiting oil way comprises a first limiting oil way, the first limiting oil way is connected between the rod cavity of the second amplitude cylinder 52 and the rodless cavity of the second amplitude cylinder 52, a motor-driven reversing valve 71 and a first one-way valve 72 are arranged on the first limiting oil way, when the motor-driven reversing valve 71 reverses to conduct the oil way, oil in the rod cavity of the second amplitude cylinder 52 can flow to an oil way connected with the rodless cavity of the second amplitude cylinder 52 in a single direction through the first one-way valve 72, the oil way on the rod cavity side of the second amplitude cylinder 52 is unloaded, and sufficient hydraulic pressure cannot be formed to push the piston rod of the second amplitude cylinder 52 to retract, namely, the second boom 32 cannot amplitude downwards.

The sizes and parameters of the first leveling cylinder 41, the second leveling cylinder 42 and the third leveling cylinder 43 are completely the same, and the setting of the parameters of each cylinder in the leveling loop and the pressure parameters of the holding valve 82 can ensure that the output forces of the first leveling cylinder 41, the second leveling cylinder 42 and the third leveling cylinder 43 are not enough to push the arm support to move, i.e., the first leveling cylinder 41, the second leveling cylinder 42 and the third leveling cylinder 43 are mutually matched for leveling the angle of the working platform 2.

The working process of the platform leveling system of the invention is as follows:

1. manual leveling

When the manual adjustment is performed, referring to fig. 5, the one-way cut-off/change-over valve 79 is energized to prevent the oil from flowing into the multi-way valve 6, and the oil passage is prevented from being decompressed from the multi-way valve 6.

When the left control end of the reversing valve 81 is electrified, the left position machine of the reversing valve 81 can work, oil flows through the retaining valve 82, passes through the rodless cavity of the third leveling cylinder 43 and the rodless cavity of the second leveling cylinder 42, flows into the rodless cavity of the first leveling cylinder 41, and the piston rod of the first leveling cylinder 41 extends out to drive the working platform 2 to pitch up.

When the right control end of the reversing valve 81 is electrified, the right machine of the reversing valve 81 can work, oil flows through the retaining valve 82, passes through the rod cavity of the third leveling cylinder 43 and the rod cavity of the second leveling cylinder 42, flows into the rod cavity of the first leveling cylinder 41, and the piston rod of the first leveling cylinder 41 retracts to drive the working platform 2 to tilt downwards.

Wherein manual leveling is normally used for initial angle setting or angle error elimination of the working platform 2.

2. Automatic leveling

The automatic leveling refers to that when the first arm support 31 and the second arm support 32 act (independent action or composite action), the platform leveling system automatically makes the working platform 2 move reversely according to the action direction of each arm support so as to adjust the angle of the platform, and always ensures that the working platform 2 is in a state of being parallel to the ground level.

Fig. 1 shows the working condition of the platform leveling system in the initial state, and the working platform 2 is manually adjusted to be level, at this time, the first luffing cylinder 51 and the second luffing cylinder 52 are retracted, the third leveling cylinder 43 is fully extended, the second leveling cylinder 42 is fully retracted, and the first leveling cylinder 41 is partially extended.

Fig. 3 shows the working condition that the first boom 31 is lifted in a variable amplitude manner and the second boom 32 is kept still, and at this time, the second variable amplitude cylinder 52 and the third leveling cylinder 43 do not act. Under the working condition, in order to prevent excessive upward pitching caused by exceeding the angle adjustable range of the working platform, the amplitude changing angle of the first boom 31 needs to be limited, namely the relative included angle a between the first boom 31 and the second boom 32 needs to be limited at a safety value.

When a piston rod of the first luffing cylinder 51 extends out to drive the first arm support 31 to luff and rise, the working platform 2 is driven to pitch up, meanwhile, the first arm support 31 drives the second leveling cylinder 42 to extend out, oil in a rod cavity of the second leveling cylinder 42 flows into the rod cavity of the first leveling cylinder 41, and the first leveling cylinder 41 retracts to drive the working platform 2 to tilt down. In the process, the oil in the rodless cavity of the first leveling cylinder 41 flows into the rodless cavity of the second leveling cylinder 42, the extending length of the second leveling cylinder 42 is equal to the retracting length of the first leveling cylinder 41, so that the angle of the working platform 2 and the angle of the first arm support 31 are adjusted in the same angle and in the opposite direction, and the working platform 2 is kept horizontal to the ground.

Similarly, when the piston rod of the first luffing cylinder 51 retracts to drive the first boom 31 to luff and descend, the working platform 2 is driven to tilt downwards, meanwhile, the first boom 31 drives the second leveling cylinder 42 to retract, oil in the rodless cavity of the second leveling cylinder 42 flows into the rodless cavity of the first leveling cylinder 41, and the first leveling cylinder 41 extends to drive the working platform 2 to pitch upwards. In the process, the oil in the rod cavity of the first leveling cylinder 41 flows into the rod cavity of the second leveling cylinder 42, the retraction length of the second leveling cylinder 42 is equal to the extension length of the first leveling cylinder 41, so that the angle of the working platform 2 and the first arm support 31 are adjusted in a similar equal angle and in a reverse direction, and the working platform 2 is kept horizontal to the ground.

Fig. 2 shows the working condition that the first boom 31 is kept still and the second boom 32 is lifted in a variable amplitude manner, and at the moment, the first variable amplitude cylinder 51 and the second leveling cylinder 42 do not act.

When the piston rod of the second luffing cylinder 52 extends out to drive the second boom 32 to luff and rise, so as to drive the working platform 2 to tilt downwards, meanwhile, the second boom 32 drives the third leveling cylinder 43 to retract, and the oil in the rodless cavity of the third leveling cylinder 43 flows into the rodless cavity of the first leveling cylinder 41, so that the first leveling cylinder 41 extends out to drive the working platform 2 to pitch upwards. In the process, the oil in the rodless cavity of the third leveling cylinder 43 flows into the rodless cavity of the first leveling cylinder 41, the retracted length of the third leveling cylinder 43 is equal to the extended length of the first leveling cylinder 41, so that the angle of the working platform 2 and the angle of the second arm support 32 are adjusted in the same angle and in the opposite direction, and the working platform 2 is kept horizontal to the ground.

Similarly, when the piston rod of the second luffing cylinder 52 extends out to drive the second boom 32 to luff and descend, the working platform 2 is driven to pitch up, meanwhile, the second boom 32 drives the third leveling cylinder 43 to extend out, oil in the rod cavity of the third leveling cylinder 43 flows into the rod cavity of the first leveling cylinder 41, and the first leveling cylinder 41 retracts to drive the working platform 2 to tilt down. In the process, the oil liquid in the rod cavity of the third leveling cylinder 43 flows into the rod cavity of the first leveling cylinder 41, the extending length of the third leveling cylinder 43 is equal to the retracting length of the first leveling cylinder 41, so that the angle of the working platform 2 and the angle of the second arm support 32 are adjusted in a similar equal angle and in a reverse direction, and the working platform 2 is kept horizontal to the ground.

Fig. 4 shows the working condition of the amplitude variation action of the first boom 31 and the second boom 32, and in order to prevent the leveling angle of the working platform 2 from exceeding the safety range, the amplitude variation and the descending of the second amplitude variation oil cylinder 52 need to be limited when the first amplitude variation oil cylinder 51 is amplitude-varied to a certain angle.

Referring to fig. 4, if = a = κ £ b, the κ value is determined according to the boom structure, the hinge point position, and the design operation range, and may be 1/2, 2/3, or other values.

Referring to fig. 5, the mobile change valve 71 is arranged at a position which can be contacted with the first luffing cylinder 51, the value of ^ a is set by setting the installation position of the mobile change valve 71, and when the luffing angle of the first luffing cylinder 51 is larger than ^ a, the descending action of the second luffing cylinder 52 is limited, but the luffing of the second boom 32 is allowed.

The first boom 31 and the second boom 32 are variable in amplitude to < b > and variable in amplitude to < c, and the first boom 31 touches the mobile reversing valve 71 at the moment to ensure that the second boom 32 cannot be lowered in amplitude as the < b > is greater than the < a >.

Under the condition that the amplitude reduction of the second arm support 32 is limited, the motorized reversing valve 71 is opened when the amplitude of the first arm support 31 reaches a preset safety angle a, and oil going to the rod cavity of the second amplitude cylinder 52 flows back to the oil tank through the first check valve 72, the motorized reversing valve 71, the oil passage on the rod cavity side of the second amplitude cylinder 52 and the multi-way valve 6. When the second boom 32 performs amplitude-variable lifting action, even if the mobile reversing valve 71 is in an open state, due to the blocking action of the first check valve 72, oil flows to the rodless cavity of the second amplitude-variable oil cylinder 52, and the lifting action of the second boom 32 is normally performed.

The sizes and parameters of the first leveling cylinder 41, the second leveling cylinder 42 and the third leveling cylinder 43 are completely the same, the first leveling cylinder 41, the second leveling cylinder 42 and the third leveling cylinder 43 are connected in parallel, the rod cavity is connected with the rod cavity, and the rod-free cavity is connected with the rod-free cavity, so that the extension and retraction length variation of the first leveling cylinder 41, the second leveling cylinder 42 and the third leveling cylinder 43 are completely equal when in linkage, and the leveling angle of the working platform 2 is accurately matched with the amplitude variation of the arm support. The platform leveling system of the invention belongs to a mechanical hydraulic leveling system, avoids complex hydraulic and electric control loops of the existing electro-hydraulic leveling system, and has the advantages of few fault points and high reliability.

Moreover, an eighth hinge point H formed by hinging the first end of the third leveling cylinder 43 with the second end of the second boom 32 is located at the tail end of the second boom 32, so that when the third leveling cylinder 43 is leveled on the working platform 2, the movement direction of the piston rod of the third leveling cylinder 43 is opposite to that of the piston rod of the first leveling cylinder 41, thereby structurally ensuring the accuracy of the platform leveling system.

The boom amplitude safety limiting oil circuit is arranged on the hydraulic loop, direct guarantee is provided for leveling safety of the working platform 2 from the aspect of a hydraulic system, the oil circuit is simple in structure, few in components, higher in reliability and more meaningful for leveling safety of the manned working platform compared with an electric control safety protection system.

On the basis of the technical scheme of the platform leveling system, the invention also provides an aerial work platform, wherein the aerial work platform comprises the platform leveling system in any technical scheme.

On the basis of the technical scheme of the aerial work platform, the invention also provides an aerial work machine, wherein the aerial work machine comprises the aerial work platform in any technical scheme.

The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.

It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. The invention is not described in detail in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.

Claims (14)

1. The platform leveling system is characterized by comprising a rotary table (1), an arm support assembly, a working platform (2) and a leveling loop, wherein the arm support assembly comprises a first arm support (31) and a second arm support (32) which are hinged to each other, the first arm support (31) is hinged to the working platform (2), the second arm support (32) is hinged to the rotary table (1), the leveling loop comprises a first leveling cylinder (41), a second leveling cylinder (42) and a third leveling cylinder (43), two ends of the first leveling cylinder (41) are hinged to the first arm support (31) and the working platform (2) respectively, two ends of the second leveling cylinder (42) are hinged to the first arm support (31) and the second arm support (32) respectively, two ends of the third leveling cylinder (43) are hinged to the second arm support (32) and the rotary table (1) respectively, the first leveling cylinder (41), the second leveling cylinder (42) and the third leveling cylinder (43) are connected with each other to form a closed oil path, and the third leveling cylinder (41) is connected with a closed oil path.

2. The platform leveling system according to claim 1, wherein a first end of the first arm support (31) is hinged to the working platform (2) through a first hinge point (a), a first end of the first leveling cylinder (41) is hinged to the working platform (2) through a second hinge point (B), a second end of the first leveling cylinder is hinged to the first end of the first arm support (31) through a third hinge point (C), a second end of the first arm support (31) is hinged to the first end of the second arm support (32) through a fourth hinge point (D), a first end of the second leveling cylinder (42) is hinged to the second end of the first arm support (31) through a fifth hinge point (E), a second end of the second arm support (32) is hinged to the first end of the second arm support (32) through a sixth hinge point (F), a second end of the second arm support (32) is hinged to the turntable (1) through a seventh hinge point (G), and a first end of the third leveling cylinder (43) is hinged to the second end of the turntable (32) through an eighth hinge point (H), and a ninth end of the second arm support (32) is hinged to the turntable (1);

when first leveling cylinder (41), second leveling cylinder (42) and third leveling cylinder (43) all are in the state of stretching entirely or contracting entirely, the triangle that first pin joint (A), second pin joint (B) and third pin joint (C) constitute, the triangle that fourth pin joint (D), fifth pin joint (E) and sixth pin joint (F) constitute and the triangle that seventh pin joint (G), eighth pin joint (H) and ninth pin joint (I) constitute wait entirely.

3. Platform leveling system according to claim 2, wherein the seventh hinge point (G) is located between the fourth hinge point (D) and the eighth hinge point (H).

4. The platform leveling system according to claim 1, wherein a first luffing cylinder (51) is installed between the first boom (31) and the second boom (32), a second luffing cylinder (52) is installed between the second boom (32) and the turntable (1), both the first luffing cylinder (51) and the second luffing cylinder (52) are connected with the multi-way valve (6), and a second boom luffing safety limiting oil path is arranged between a rod chamber and a non-rod chamber of the second luffing cylinder (52).

5. The platform leveling system according to claim 4, wherein the second boom amplitude safety limiting oil circuit comprises a first limiting oil circuit connected between a rod cavity and a rodless cavity of the second amplitude cylinder (52), the first limiting oil circuit is provided with a motorized reversing valve (71) and a first one-way valve (72) capable of guiding oil in the rod cavity of the second amplitude cylinder (52) to the oil circuit connected with the rodless cavity in a single direction, and a control end of the motorized reversing valve (71) is arranged opposite to the first boom (31).

6. The platform leveling system according to claim 4 or 5, wherein the second boom luffing safety restriction oil circuit comprises a second restriction oil circuit connected between the rod chamber and the rodless chamber of the second luffing cylinder (52), and the second restriction oil circuit is provided with a first electromagnetic directional valve (73) and a second one-way valve (74) capable of unidirectionally guiding oil in the rod chamber of the second luffing cylinder (52) to the oil circuit connected to the rodless chamber thereof.

7. The platform leveling system according to claim 4 or 5, wherein a first boom luffing safety restriction oil passage is provided between the rod chamber and the rodless chamber of the first luffing cylinder (51).

8. The platform leveling system according to claim 7, wherein a second electromagnetic directional valve (75) and a third one-way valve (76) capable of guiding oil in a rodless cavity of the first luffing cylinder (51) to a rodless cavity thereof in a single direction are arranged on the first boom luffing safety limiting oil path.

9. Platform levelling system according to claim 4 or 5, characterized in that a first balancing valve (77) is arranged between the first luffing cylinder (51) and the multiplex valve (6) and a second balancing valve (78) is arranged between the second luffing cylinder (52) and the multiplex valve (6).

10. The platform leveling system according to claim 4 or 5, wherein the oil inlet of the multi-way valve (6) is connected with a one-way cut-off and reversing valve (79).

11. The platform leveling system according to any one of claims 1 to 5, wherein the leveling circuit further comprises a directional valve (81) and a holding valve (82), the directional valve (81) being connected with the third leveling cylinder (43) through the holding valve (82).

12. Platform levelling system according to any one of claims 1 to 5, characterized in that a third balancing valve (83) is provided between the first levelling cylinder (41) and the second levelling cylinder (42).

13. An aerial work platform, characterized in that a platform levelling system as claimed in any one of claims 1 to 12 is provided.

14. An aerial work machine, characterized in that an aerial work platform according to claim 13 is provided.

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