Axle-extendable chassis and design method therefor, and mobile lifting working platform

Abstract

Disclosed in the present disclosure is an axle-extendable chassis, comprising: a vehicle frame; one or more axle components, which each comprise a first assembly and a second assembly which are arranged on one side of the vehicle frame, the first assembly comprising a first swing leg and a wheel mounted at a first end of the first swing leg, the second assembly comprising a second swing leg and a wheel mounted at a first end of the second swing leg, the part between the first end and a second end of the first swing leg being hinged to the vehicle frame, and a second end of the second swing leg being hinged to the vehicle frame; and driving components, which each comprise a first connecting rod, a second connecting rod and a double-head piston rod telescopic cylinder, wherein the double-head piston rod telescopic cylinder comprises a cylinder barrel fixedly connected to the vehicle frame, a piston located in the cylinder barrel, and a double-head piston rod fixedly connected to the piston and passing through the cylinder barrel, two ends of the first connecting rod being respectively hinged to the second end of the first swing leg and a first end of the double-head piston rod, and two ends of the second connecting rod being respectively hinged to the part between the first end and the second end of the second swing leg and a second end of the double-head piston rod.

Description

Expandable bridge chassis and design method thereof and mobile lifting work platform

[0001] Related applications

[0002] This application is based on and claims priority to the Chinese patent application with application number 202311623368.9, application date November 29, 2023, and invention name “Expandable bridge chassis, design method thereof, and mobile lifting work platform”. The disclosed content of the Chinese patent application is hereby introduced as a whole into this application. Technical Field

[0003] The present disclosure relates to the technical fields of engineering and special machinery, and in particular to an expandable bridge chassis and a mobile lifting work platform. Background Art

[0004] Expandable axle chassis are used in some engineering machinery or special machinery fields. For example, some high-meter mobile lifting work platforms use a frame with a bridge expansion function to increase the operating stability of the whole machine. The mobile lifting work platform is a kind of equipment in the fields of high-altitude operations such as construction, interior and exterior decoration, and steel structure. During transportation, the mobile lifting work platform can use the expandable axle chassis to retract the swing legs and reduce the width of the whole vehicle to meet the size restrictions of road transportation or driving; during operation, the bridge expansion function can be used to unfold the swing legs and increase the span of the legs, bringing better operating stability to the high-meter mobile lifting work platform. The chassis of the mobile lifting work platform of the related art known to the inventor includes a frame 3a, a front axle component 1a, a rear axle component 2a and four bridge expansion cylinders 4a as shown in Figures 1 and 2. The front axle component 1a and the rear axle component 2a each have two swing legs 5a. The four swing arms 5a are hinged to the vehicle frame 3a via pins. Each of the four axle expansion cylinders 4a is pinned to the vehicle frame at one end and to the swing arms at the other. The four swing arms can be extended and retracted by the expansion cylinders, rotating around the pins connecting them to the vehicle frame, thereby expanding and retracting the axle. When the vehicle is in transport or road mode, the expansion cylinders retract, retracting the axle as shown in Figure 2. When the vehicle is ready for operation, the four expansion cylinders extend synchronously, causing the swing arms to deploy simultaneously, bringing the vehicle to the expanded axle state as shown in Figure 1.

[0005] Summary of the Invention

[0006] An expandable bridge chassis capable of expanding and contracting the bridge, a mobile lifting work platform using the expandable bridge chassis, and a design method for the expandable bridge chassis.

[0007] A first aspect of the present disclosure discloses an expandable bridge chassis, comprising:

[0008] Frame;

[0009] One or more axle components, including a first assembly and a second assembly provided on one side of the vehicle frame, the first assembly including a first swing leg and a wheel mounted on a first end of the first swing leg, the second assembly including a second swing leg and a wheel mounted on a first end of the second swing leg, a portion between the first and second ends of the first swing leg being hinged to the vehicle frame, and the second end of the second swing leg being hinged to the vehicle frame;

[0010] The driving component includes a first connecting rod, a second connecting rod and a double-headed piston rod telescopic cylinder, the double-headed piston rod telescopic cylinder includes a cylinder barrel fixedly connected to the frame, a piston located in the cylinder barrel and a double-headed piston rod fixedly connected to the piston and passing through the cylinder barrel, the two ends of the first connecting rod are respectively hinged to the second end of the first swing leg and the first end of the double-headed piston rod, the two ends of the second connecting rod are respectively hinged to the part between the first end and the second end of the second swing leg and to the second end of the double-headed piston rod.

[0011] In some embodiments, the distance between the hinge point of the double-headed piston rod with the first connecting rod and the hinge point of the double-headed piston rod with the second connecting rod is equal to twice the length of the moving range of the piston in the cylinder, and the hinge point of the double-headed piston rod with the first connecting rod and the hinge point of the double-headed piston rod with the second connecting rod are symmetrically distributed relative to the piston.

[0012] In some embodiments, the distance between the hinge point of the first swing leg and the frame and the hinge point of the first swing leg and the first connecting rod is equal to the distance between the hinge point of the second swing leg and the frame and the hinge point of the second swing leg and the second connecting rod.

[0013] In some embodiments, the length of the first link is equal to the length of the second link.

[0014] In some embodiments, the midpoint of a line connecting a hinge point where the first swing leg is hinged to the frame and a hinge point where the second swing leg is hinged to the frame is the midpoint of a moving range of the piston in the cylinder.

[0015] In some embodiments, the expandable axle chassis has a retracted state in which the first swing leg and the second swing leg of the axle component are close to each other and an expanded state in which the first swing leg and the second swing leg of the axle component are away from each other. In the retracted state, the piston is in a first extreme position in the cylinder, and in the expanded state, the piston is in a second extreme position opposite to the first extreme position in the cylinder. The line connecting the hinge point of the first swing leg and the first connecting rod and the hinge point of the second swing leg and the second connecting rod is parallel in the retracted state and in the expanded state, and is parallel to the movement trajectory of the piston between the first extreme position and the second extreme position.

[0016] In some embodiments, the expandable axle chassis includes two oppositely arranged axle components, wherein the two axle components are respectively arranged at the front side and the rear side of the frame.

[0017] A second aspect of the present disclosure discloses a mobile lifting work platform, comprising any of the expandable bridge chassis described above.

[0018] A third aspect of the present disclosure discloses a design method for any of the above-described expandable axle chassis, wherein the expandable axle chassis has a retracted state in which a first swing leg and a second swing leg of an axle component approach each other, and an expanded state in which the first swing leg and the second swing leg of the axle component move away from each other, wherein the hinge point of the first swing leg hinged to the vehicle frame is point O1, and the hinge point of the second swing leg hinged to the vehicle frame is point O2. The design method for the expandable axle chassis comprises:

[0019] Step 100, determine the radius R, the positions of point O1 and point O2, and draw a first circle with a radius R with point O1 as the center, and draw a second circle with a radius R with point O2 as the center;

[0020] Step 200 includes method F1 or method F2, wherein method F1 includes: taking point a and point a' on the first circle as the hinge points between the first swing leg and the first connecting rod in the bridge-retracted state and the bridge-extended state respectively; connecting point a and point a' to form a line segment aa'; translating the line segment aa' to the second circle so that both endpoints of the line segment aa' are located on the second circle, taking the point on the second circle that coincides with the endpoint of the line segment aa' corresponding to point a as point b, and taking the point on the second circle that coincides with the endpoint of the line segment aa' corresponding to point a' as point b. The point that coincides with the second swing leg is defined as point b'; Method F2 includes: selecting points b and b' on the second circle as the hinge points between the second swing leg and the second connecting rod in the retracted and extended bridge states, respectively; connecting points b and b' to form a line segment bb'; translating the line segment bb' onto the first circle so that both endpoints of the line segment bb' lie on the first circle; defining the point on the first circle that coincides with the endpoint of the line segment bb' corresponding to point b as point a; and defining the point on the first circle that coincides with the endpoint of the line segment bb' corresponding to point b' as point a';

[0021] Step 300: Draw a line segment k symmetrically about the midpoint of the line connecting points O1 and O2 and parallel to the line connecting points a and b. The two endpoints of the line segment k are used as the first and second extreme positions of the piston. In the bridge-retracted state, the piston is at the first extreme position in the cylinder. In the bridge-extended state, the piston is at the second extreme position opposite to the first extreme position in the cylinder. The length of the line segment k is the length of the line segment aa' plus x0. Two points are taken on the extension lines on both sides of the line segment at a distance y from the two end points of the line segment. The point close to the first circle is point C1, and the point close to the second circle is point C2.

[0022] Step 400: Use point C1 as the hinge point between the double-ended piston rod and the first connecting rod in the expanded bridge state, and use point C2 as the hinge point between the double-ended piston rod and the second connecting rod in the retracted bridge state;

[0023] Step 500 , after step 400 , correct and determine the length of the K-line segment.

[0024] In some embodiments, after step 400, correcting and determining the length of the k-line segment includes:

[0025] Model the expandable axle chassis using the data obtained after step 400. Start the expandable axle chassis model from the retracted state, move the piston from the second extreme position to the first extreme position, and verify whether the hinge point of the first connecting rod and the double-rod piston rod reaches point a from point a'.

[0026] If the hinge point between the first connecting rod and the double-rod piston rod reaches point a, the length of the k-segment at this point is determined;

[0027] If the hinge point between the first connecting rod and the double-rod piston rod exceeds point a, the value of x0 is reduced and the process continues to step 500;

[0028] If the hinge point between the first connecting rod and the double-rod piston rod has not reached point a, the value of x0 is increased and step 500 is continued.

[0029] In some embodiments, translating the aa' segment to the second circle so that both endpoints of the aa' segment are located on the second circle includes: translating the aa' segment to a portion of the second circle on a different side of the line connecting points O1 and O2 from point a.

[0030] In some embodiments, the value of y is 0.

[0031] Based on the expandable axle chassis provided by the present invention, by setting components such as a first connecting rod, a second connecting rod and a double-headed piston rod telescopic cylinder, only one telescopic cylinder is used in an axle component to simultaneously control the two swing legs of the axle component to retract or expand at the same time, which has a simple and compact structure and good synchronization.

[0032] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0034] FIG1 is a schematic structural diagram of an expandable bridge chassis in the related art in the expanded bridge state;

[0035] FIG2 is a schematic structural diagram of the expandable bridge chassis shown in FIG1 in the bridge retracted state;

[0036] FIG3 is a schematic structural diagram of a mobile lifting work platform according to an embodiment of the present disclosure;

[0037] FIG4 is a schematic structural diagram of the expandable bridge chassis in the bridge-folded state according to an embodiment of the present disclosure;

[0038] FIG5 is a schematic structural diagram of the expandable bridge chassis shown in FIG4 in the expanded bridge state;

[0039] FIG6 is a schematic diagram of a design method for an expandable bridge chassis according to an embodiment of the present disclosure;

[0040] FIG. 7 is a schematic diagram of a design method for an expandable bridge chassis according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0041] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0042] Unless otherwise specifically stated, the relative arrangement of the parts and steps, the numerical expressions and the numerical values ​​set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values ​​should be interpreted as being merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0043] As shown in FIG. 3 to FIG. 5 , the expandable axle chassis 120 of this embodiment includes a vehicle frame 1 , one or more axle components, and a driving component.

[0044] Frame 1;

[0045] The axle components include a first component and a second component provided on one side of the vehicle frame 1. In the embodiments shown in Figures 4 and 5, the expandable bridge chassis includes two axle components, which are respectively located on the front and rear sides of the vehicle frame 1 along the direction of travel of the expandable bridge chassis. The first component includes a first swing leg 21 and a wheel 23 mounted on the first end of the first swing leg 21. The second component includes a second swing leg 22 and a wheel 23 mounted on the first end of the second swing leg 22. The portion between the first and second ends of the first swing leg 21 is hinged to the vehicle frame 1, and the second end of the second swing leg 22 is hinged to the vehicle frame 1. The wheel 23 is rotatably mounted on the swing leg and is used for the travel of the expandable bridge chassis. In some embodiments, the wheel 23 is driven to rotate by a motor provided on the swing leg.

[0046] The drive components include a first connecting rod 31, a second connecting rod 32, and a double-headed piston rod telescopic cylinder. The double-headed piston rod telescopic cylinder includes a cylinder barrel 331 fixedly connected to the vehicle frame 1, a piston located in the cylinder barrel 331, and a double-headed piston rod 332 fixedly connected to the piston and extending through the cylinder barrel 331. A double-headed piston rod is a piston rod with both ends extending out of the cylinder barrel. The movement of the piston within the cylinder barrel 331 drives the double-headed piston rod and the piston to move in the same direction. The double-headed piston rod telescopic cylinder comprises a double-headed piston rod oil cylinder or a double-headed piston rod air cylinder. The two ends of the first connecting rod 31 are respectively hinged to the second end of the first swing leg 21 and the first end of the double-headed piston rod 332. The two ends of the second connecting rod 32 are respectively hinged to the portion between the first and second ends of the second swing leg 22 and to the second end of the double-headed piston rod 332.

[0047] The expandable axle chassis 120 has a retracted state as shown in FIG4 and an expanded state as shown in FIG5 . In the retracted state, the first and second swing legs of the axle component approach each other, and in the expanded state, the first and second swing legs of the axle component move away from each other. The piston can move back and forth in the cylinder 331. When the piston is driven from one end of the cylinder to the other end of the cylinder, the piston can drive the double-headed piston rod to move in one direction. The two ends of the double-headed piston rod respectively drive the first connecting rod 31 and the second connecting rod 32 to move. The first connecting rod 31 and the second connecting rod 32 respectively drive the first swing leg 21 and the second swing leg to rotate relative to the vehicle frame, so that the first swing leg 21 and the second swing leg 22 approach each other or move away from each other. The reciprocating movement of the piston in the cylinder can realize the switching of the expandable axle chassis between the retracted state and the expanded state.

[0048] The expandable axle chassis 120 of this embodiment can use a telescopic cylinder to simultaneously control the two swing legs of the axle component to contract or expand at the same time by providing components such as the first connecting rod 31, the second connecting rod 32 and the double-headed piston rod telescopic cylinder. It has a simple and compact structure and good synchronization.

[0049] In some embodiments, the distance between the hinge point where the double-headed piston rod 332 is hinged to the first connecting rod 31 and the hinge point where the double-headed piston rod 332 is hinged to the second connecting rod 32 is equal to twice the length of the range of movement of the piston in the cylinder 331, and the hinge point where the double-headed piston rod 332 is hinged to the first connecting rod 31 and the hinge point where the double-headed piston rod 332 is hinged to the second connecting rod 32 are symmetrically distributed relative to the piston. The piston moves in a straight line in the cylinder 331, and its extreme positions of movement are respectively a first extreme position and a second extreme position. The range between the first extreme position and the second extreme position is the range of movement of the piston in the cylinder. That is, in this embodiment, the distance between the hinge point where the double-headed piston rod 332 is hinged to the first connecting rod 31 and the hinge point where the double-headed piston rod 332 is hinged to the second connecting rod 32 is twice the distance between the first extreme position and the second extreme position. The hinge point of the double-headed piston rod 332 hinged to the first connecting rod 31 and the hinge point of the double-headed piston rod 332 hinged to the second connecting rod 32 are symmetrically distributed relative to the piston, that is, the distance from the hinge point of the double-headed piston rod 332 hinged to the first connecting rod 31 to the piston is equal to the distance from the hinge point of the double-headed piston rod 332 hinged to the second connecting rod 32. In some embodiments, in the bridge-retracted state, the piston is in a first extreme position in the cylinder 331, and in the bridge-expanded state, the piston is in a second extreme position opposite to the first extreme position in the cylinder 331, so that when the piston moves to the first extreme position, the hinge point of the double-headed piston rod 332 hinged to the first connecting rod 31 is farthest from the cylinder, and the hinge point of the double-headed piston rod 332 hinged to the second connecting rod 32 reaches the second extreme position, and when the piston moves to the second extreme position, the hinge point of the double-headed piston rod 332 hinged to the second connecting rod 32 is farthest from the cylinder, and the hinge point of the double-headed piston rod 332 hinged to the first connecting rod 31 reaches the first extreme position, that is, the cylinder of this embodiment can make the length close to the distance between the first extreme position and the second extreme position, making the cylinder as short as possible, and at the same time making the length of the double-headed piston rod approximately equal to twice the distance between the first extreme position and the second extreme position, making the length of the double-headed piston rod as short as possible, thereby making the overall structure of the double-headed piston rod telescopic cylinder compact.

[0050] In some embodiments, the distance between the hinge point where the first swing leg 21 is hinged to the vehicle frame 1 and the hinge point where the first swing leg 21 is hinged to the first connecting rod 31 is equal to the distance between the hinge point where the second swing leg 22 is hinged to the vehicle frame 1 and the hinge point where the second swing leg 22 is hinged to the second connecting rod 32. This helps ensure that the first and second swing legs have similar or identical angles when they rotate relative to the vehicle frame.

[0051] In some embodiments, the length of the first connecting rod 31 is equal to the length of the second connecting rod 32. In this embodiment, the first connecting rod and the second connecting rod are equal in length, which helps to make the first swing leg and the second swing leg rotate at similar or identical angles relative to the frame.

[0052] In some embodiments, the midpoint of the line connecting the hinge point between the first swing leg 21 and the frame 1 and the hinge point between the second swing leg 22 and the frame 1 is the midpoint of the piston's range of motion within the cylinder 331. That is, in this embodiment, the center of the cylinder 331 is located at the midpoint of the line connecting the hinge point between the first swing leg 21 and the frame 1 and the hinge point between the second swing leg 22 and the frame 1.

[0053] In some embodiments, the expandable axle chassis 120 has a retracted state in which the first swing leg 21 and the second swing leg 22 of the axle component are close to each other, and an expanded state in which the first swing leg 21 and the second swing leg 22 of the axle component are separated from each other. In the retracted state, the piston is in a first extreme position in the cylinder 331, and in the expanded state, the piston is in a second extreme position opposite to the first extreme position in the cylinder 331. The line connecting the hinge point of the first swing leg 21 and the first connecting rod 31 and the hinge point of the second swing leg 22 and the second connecting rod is parallel in the retracted state and the expanded state, and is parallel to the movement trajectory of the piston between the first extreme position and the second extreme position. When this embodiment switches from the retracted state to the expanded state, the first swing leg and the second swing leg have the same swing angle relative to the frame, and the expandable axle chassis can be supported more stably and evenly on the bottom surface.

[0054] In some embodiments, the expandable axle chassis includes two oppositely arranged axle components, as shown in Figures 3 and 5 , which are respectively arranged at the front and rear sides of the vehicle frame 1. The front and rear sides are referenced to the direction of travel when the expandable axle chassis is installed, with the forward direction being the front and the backward direction being the rear.

[0055] In some embodiments, as shown in FIG3 , a mobile elevating work platform 100 is also disclosed. The mobile elevating work platform 100 includes any of the aforementioned expandable bridge chassis 120. The mobile elevating work platform 100 includes a work platform 110, which is mounted on a workbench via an arm 130. The workbench is mounted on the expandable bridge chassis 120. Rotating the arm 130 relative to the workbench raises or lowers the work platform 110, thereby adjusting the height of an operator on the work platform 110. When the expandable bridge chassis 120 moves, the mobile elevating work platform 100 moves as a whole.

[0056] In some embodiments, as shown in FIG6 and FIG7 , a design method for any of the above-mentioned expandable bridge chassis 120 is also disclosed. The expandable bridge chassis 120 has a bridge-retracted state in which the first swing leg 21 and the second swing leg 22 of the bridge component are close to each other, and a bridge-extended state in which the first swing leg 21 and the second swing leg 22 of the bridge component are separated from each other. The hinge point of the first swing leg 21 and the frame 1 is point O1, and the hinge point of the second swing leg 22 and the frame 1 is point O2. The first and second swing legs in solid lines in FIG6 and FIG7 are the first and second swing legs in the bridge-retracted state, and the first and second swing legs in dashed lines are the first and second swing legs in the bridge-extended state. The design method for the expandable bridge chassis 120 includes:

[0057] Step 100, determine the size of the radius length R, the position of point O1 and the position of point O2, and make a first circle with a radius length R with point O1 as the center, and make a second circle with a radius length R with point O2 as the center; the size of the radius length R can be selected to a suitable value based on parameters such as the structural dimensions of the expandable bridge chassis.

[0058] Step 200 includes method F1 or method F2, wherein method F1 includes: taking point a and point a' on the first circle as the hinge points of the first swing leg 21 and the first connecting rod 31 in the bridge-retracted state and the bridge-extended state respectively; connecting point a and point a' to form aa' segment; translating the aa' segment to the second circle so that both endpoints of the aa' segment are located on the second circle, taking the point on the second circle that coincides with the endpoint of the aa' segment corresponding to point a as point b, and taking the point on the second circle that coincides with the endpoint of the aa' segment corresponding to point a' as point b. The point that coincides with the second swing leg 22 is defined as point b'; Method F2 includes: selecting points b and b' on the second circle as the hinge points between the second swing leg 22 and the second connecting rod 32 in the retracted and expanded bridge states, respectively; connecting points b and b' to form a line segment bb'; translating the line segment bb' onto the first circle so that both endpoints of the line segment bb' are located on the first circle; defining the point on the first circle that coincides with the endpoint of the line segment bb' corresponding to point b as point a; and defining the point on the first circle that coincides with the endpoint of the line segment bb' corresponding to point b' as point a';

[0059] Step 300, make a k-segment symmetrical about the midpoint of the line connecting points O1 and O2 (point O as shown in Figures 6 and 7) through the midpoint of the line connecting points O1 and O2 and parallel to the line connecting points a and b, and use the two endpoints of the k-segment as the first limit position and the second limit position of the piston. In the bridge-retracted state, the piston is in the first limit position in the cylinder 331, and in the bridge-expanded state, the piston is in the second limit position opposite to the first limit position in the cylinder 331. The length of the k-segment is the length of the aa' segment plus x0, and two points are taken on the extension lines on both sides of the k-segment at a distance y from the two end points of the k-segment, where the point close to the first circle is point C1, and the point close to the second circle is point C2; the value of y can be arbitrarily taken as a smaller value not greater than R according to the position of the first swing leg and the second swing leg and the frame hinge point.

[0060] Step 400: Use point C1 as the hinge point between the double-headed piston rod 332 and the first connecting rod 31 in the expanded state, and use point C2 as the hinge point between the double-headed piston rod 332 and the second connecting rod 32 in the retracted state.

[0061] Step 500 , after step 400 , correct and determine the length of the K-line segment.

[0062] In some embodiments, after step 400, correcting and determining the length of the k-line segment includes:

[0063] Model the expandable bridge chassis 120 using the data obtained after step 400. Start the expandable bridge chassis 120 model from the bridge retracted state, move the piston from the second extreme position to the first extreme position, and verify whether the hinge point of the first connecting rod 31 and the double-rod piston rod reaches point a from point a';

[0064] If the hinge point between the first connecting rod 31 and the double-rod piston rod reaches point a, the length of the k-segment at this point is determined;

[0065] If the hinge point between the first connecting rod 31 and the double-rod piston rod exceeds point a, the value of x0 is reduced and the process continues to step 500;

[0066] If the hinge point between the first connecting rod 31 and the double-rod piston rod has not reached point a, the value of x0 is increased and step 500 is continued.

[0067] That is, this embodiment needs to determine the length of the k-segment, mainly by correcting the value of x0 to determine the length of the k-segment. The initial value of x0 can be any smaller number. For example, 5% of the length of the aa' segment can be taken as the initial value of x0, thereby obtaining the initial value of the length of the k-segment. According to the initial value of x0, combined with the steps of the previous embodiment, it can be designed to obtain the position of the hinge point C1 of the double-headed piston rod 332 and the first connecting rod 31 when it is in the expanded bridge state, that is, when the piston is located at the end point of the k-segment close to the second circle, that is, at the second extreme position. Point a' is also the position of the hinge point between the first connecting rod 31 and the first swing leg in the expanded bridge state. According to the initial value of the length of the k-segment, the position and angle of the k-segment, and the position of point O1, it is established that the double-headed piston rod telescopic cylinder drives the first swing leg to swing through the first connecting rod. In the model, the initial value of the piston is located at the endpoint of the k-line segment close to the second circle, that is, the second extreme position. At this time, the hinge point of the first connecting rod and the first swing leg is at point a'. When the piston moves from the second extreme position to the first extreme position, that is, the end position of the k-line segment close to the first circle, the simulation is carried out to see whether the double-headed piston rod can drive the hinge point of the first swing leg and the first connecting rod to point a through the first connecting rod. If the hinge point of the first connecting rod 31 and the double-rod piston rod reaches point a, it means that the value of x0 is appropriate, and the length of the k-line segment at this time is determined. If the hinge point of the first connecting rod 31 and the double-rod piston rod exceeds point a, it means that the value of x0 is too large and the value of x0 needs to be reduced. The process continues with step 500, that is, the length of the k-line segment is verified and determined based on the new value of x0. If the hinge point of the first connecting rod 31 and the double-rod piston rod does not reach point a, it means that the value of x0 is too small and the value of x0 needs to be increased. The process continues with step 500. Once the length of the K-line segment has been verified and determined, the positions of the hinge points among the first connecting rod, the second connecting rod, the first swing leg, the second swing leg and other components can be determined, so that an expandable bridge chassis can be designed in which the swing angle of the first swing leg and the swing angle of the second swing leg are equal when switching between the retracted bridge state and the expanded bridge state.

[0068] In some embodiments, modeling can be performed using 3D software such as UG (Unigraphics NX) and CATIA (Computer Aided Three-dimensional Interactive Application).

[0069] In some embodiments, the correction and determination of the length of the k-line segment after step 400 can also be performed by geometric calculation.

[0070] In some embodiments, translating line segment aa' onto the second circle so that both endpoints of line segment aa' lie on the second circle includes translating line segment aa' onto a portion of the second circle on a different side of the line connecting points O1 and O2 than point a on the first circle. That is, points b and b' on the second circle are located on different sides of the line connecting points O1 and O2 than points a and a' on the first circle.

[0071] In some embodiments, the value of y is 0. The length of the cylinder barrel of this embodiment can be made close to the distance between the first extreme position and the second extreme position, making the cylinder barrel as short as possible. At the same time, the length of the double-ended piston rod is approximately equal to twice the distance between the first extreme position and the second extreme position, making the length of the double-ended piston rod as short as possible, thereby making the overall structure of the double-ended piston rod telescopic cylinder compact.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solutions of the present invention. They should all be included in the scope of the technical solutions claimed for protection by the present invention.

Claims

1. An expandable bridge chassis (120), wherein, comprising: a vehicle frame (1); One or more axle components, including a first component and a second component provided on one side of the vehicle frame (1). The first component includes a first swing leg (21) and a wheel (23) mounted at the first end of the first swing leg (21). The second component includes a second swing leg (22) and a wheel (23) mounted at the first end of the second swing leg (22). The portion between the first end and the second end of the first swing leg (21) is hinged to the vehicle frame (1), and the second end of the second swing leg (22) is hinged to the vehicle frame (1); a driving component, including a first connecting rod (31), a second connecting rod (32) and a double-headed piston rod telescopic cylinder. The double-headed piston rod telescopic cylinder includes a cylinder barrel (331) fixedly connected to the vehicle frame (1), a piston located in the cylinder barrel (331), and a double-headed piston rod (332) fixedly connected to the piston and passing through the cylinder barrel (331). The two ends of the first connecting rod (31) are respectively hinged to the second end of the first swing leg (21) and the first end of the double-headed piston rod (332). The two ends of the second connecting rod (32) are respectively hinged to the portion between the first end and the second end of the second swing leg (22) and the second end of the double-headed piston rod (332).

2. The expandable bridge chassis (120) according to claim 1, wherein, the distance between the hinge point of the double-headed piston rod (332) hinged to the first connecting rod (31) and the hinge point of the double-headed piston rod (332) hinged to the second connecting rod (32) is equal to twice the length of the moving range of the piston in the cylinder barrel (331), and the hinge point of the double-headed piston rod (332) hinged to the first connecting rod (31) and the hinge point of the double-headed piston rod (332) hinged to the second connecting rod (32) are symmetrically distributed relative to the piston.

3. The expandable bridge chassis (120) according to claim 1 or 2, wherein, the distance between the hinge point of the first swing leg (21) hinged to the vehicle frame (1) and the hinge point of the first swing leg (21) hinged to the first connecting rod (31) is equal to the distance between the hinge point of the second swing leg (22) hinged to the vehicle frame (1) and the hinge point of the second swing leg (22) hinged to the second connecting rod (32).

4. The expandable bridge chassis (120) according to any one of claims 1 to 3, wherein, the length of the first connecting rod (31) is equal to the length of the second connecting rod (32).

5. The expandable bridge chassis (120) according to any one of claims 1 to 4, wherein, the midpoint of the line connecting the hinge point of the first swing leg (21) hinged to the vehicle frame (1) and the hinge point of the second swing leg (22) hinged to the vehicle frame (1) is the midpoint of the moving range of the piston in the cylinder barrel (331).

6. The expandable bridge chassis (120) according to any one of claims 1 to 5, wherein, The expandable bridge chassis (120) has a retracted bridge state in which the first swing leg (21) and the second swing leg (22) of the axle components are close to each other, and an expanded bridge state in which the first swing leg (21) and the second swing leg (22) of the axle components are away from each other. In the retracted bridge state, the piston is in a first extreme position within the cylinder barrel (331). In the expanded bridge state, the piston is in a second extreme position opposite to the first extreme position within the cylinder barrel (331). The line connecting the hinge point where the first swing leg (21) is hinged to the first connecting rod (31) and the hinge point where the second swing leg (22) is hinged to the second connecting rod (32) is parallel in the retracted bridge state and in the expanded bridge state, and is parallel to the movement locus of the piston moving between the first extreme position and the second extreme position.

7. The expandable bridge chassis (120) according to any one of claims 1 to 6, wherein, it includes two relatively arranged axle components, and the two axle components are respectively arranged on the front side and the rear side of the vehicle frame (1).

8. A mobile lifting work platform (100), wherein, it includes the expandable bridge chassis (120) according to any one of claims 1 to 7.

9. A design method of the expandable bridge chassis (120) according to any one of claims 1 to 7, the expandable bridge chassis (120) has a retracted bridge state in which the first swing leg (21) and the second swing leg (22) of the axle components are close to each other, and an expanded bridge state in which the first swing leg (21) and the second swing leg (22) of the axle components are away from each other. The hinge point where the first swing leg (21) is hinged to the vehicle frame (1) is point O1, and the hinge point where the second swing leg (22) is hinged to the vehicle frame (1) is point O2. wherein, the design method of the expandable bridge chassis (120) includes: Step 100, determining the size of the radius length R, the position of point O1, and the position of point O2. With point O1 as the center, draw a first circle with a radius length of R. With point O2 as the center, draw a second circle with a radius length of R; Step 200, includes method F1 or method F2, wherein method F1 includes: taking point a and point a' on the first circle as the hinge points of the first swing leg (21) and the first connecting rod (31) in the retracted bridge state and the expanded bridge state respectively; Connect point a and point a' to form line segment aa'; translate line segment aa' to the second circle such that both endpoints of line segment aa' are on the second circle. The point on the second circle that coincides with the endpoint of line segment aa' corresponding to point a at this time is taken as point b, and the point on the second circle that coincides with the endpoint of line segment aa' corresponding to point a' at this time is taken as point b'; Method F2 includes: taking point b and point b' on the second circle as the hinge points of the second swing leg (22) and the second connecting rod (32) in the bridge retracted state and the bridge extended state respectively; connect point b and point b' to form line segment bb'; translate line segment bb' to the first circle such that both endpoints of line segment bb' are on the first circle. The point on the first circle that coincides with the endpoint of line segment bb' corresponding to point b at this time is taken as point a, and the point on the first circle that coincides with the endpoint of line segment bb' corresponding to point b' at this time is taken as point a'. Step 300: Draw a k line segment that is symmetric about the midpoint of the line connecting O1 and O2 and parallel to the line connecting point a and point b through the midpoint of the line connecting O1 and O2. The two endpoints of the k line segment are taken as the first extreme position and the second extreme position of the piston. In the bridge retracted state, the piston is at the first extreme position within the cylinder (331). In the bridge extended state, the piston is at the second extreme position opposite to the first extreme position within the cylinder (331). Take the length of the k line segment as the length of the aa' line segment plus x0. Take two points on the extension lines on both sides of the k line segment at a distance of y from the two endpoints of the k line segment. The point closer to the first circle is point C1, and the point closer to the second circle is point C2. Step 400: Take point C1 as the hinge point of the double-headed piston rod (332) and the first connecting rod (31) in the bridge extended state, and take point C2 as the hinge point of the double-headed piston rod (332) and the second connecting rod (32) in the bridge retracted state. Step 500: After step 400, correct and determine the length of the k line segment.

10. The design method of the bridge-expandable chassis (120) as claimed in claim 9, wherein, After step 400, correcting and determining the length of the k line segment includes: Using the data obtained after step 400 to model the bridge-expandable chassis (120), starting from the bridge retracted state of the bridge-expandable chassis (120) model, moving the piston from the second extreme position to the first extreme position, and verifying whether the hinge point of the first connecting rod (31) and the double-rod piston rod reaches point a from point a'; If the hinge point of the first connecting rod (31) and the double-rod piston rod reaches point a, then determine the length of the k line segment at this time; If the hinge point of the first connecting rod (31) and the double-rod piston rod exceeds point a, then reduce the value of x0 and continue with step 500; If the hinge point of the first connecting rod (31) and the double-rod piston rod does not reach point a, then increase the value of x0 and continue with step 500.

11. The design method of the bridge-expandable chassis (120) as claimed in claim 9 or 10, wherein, Said translation of the line segment aa' to the second circle such that both endpoints of the line segment aa' are located on the second circle includes: translating the line segment aa' to the part of the second circle that is on the side different from the connection line of points O1 and O2 with respect to the point a.

12. The design method of the expandable bridge chassis (120) according to any one of claims 9 to 11, wherein, the value of y is 0.

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