Trolley mechanism

Abstract

A trolley mechanism is characterized in that the trolley mechanism comprises a movable trolley and a ground fixing system, and the ground fixing system is used for being matched with the trolley to position the trolley and locking the trolley in place so as to be matched with an elevator to pick up and convey a trolley body. By means of the trolley mechanism, the trolley can be conveniently received from the elevator or conveyed to the elevator without a tray.

Description

Technical Field

[0001] The present application relates to the technical field of automobile manufacturing, and in particular to a trolley mechanism for transporting a vehicle body, which is particularly used for cooperating with an elevator at an elevator station to pick up a vehicle from the elevator. Background Art

[0002] In the process of automobile manufacturing, it is necessary to transfer the car body between different production lines and stations. The car body generally includes the body in white (referring to the car body that has been welded but not yet painted) and the painted car body. Such car bodies are usually moved to the required station by a lift before being assembled with the gearbox, engine, etc., and then the car body is transported to the outside or transferred within the site by a forklift, such as being transferred to the measurement center in the workshop for quality measurement of the car body. However, traditionally, the lift pick-up / drop-off station is set up so that: the car body must first fall onto the blue pallet in the station through the lift, and the forklift can only take the car body from the lift station through the pallet, or the forklift can only put the car body with the pallet into the lift station, and then the lift takes the car body from the pallet. Therefore, on the one hand, if there is no such pallet, the forklift cannot take the car body from the lift, and on the other hand, the car body with the pallet taken away by the forklift cannot be transferred to the measurement center for subsequent measurement, because the measurement center can only receive the car body without the pallet.

[0003] In addition, the lift station still needs to retain its main pallet retrieval function for workshop production.

[0004] Based on this, there is a need to realize the pick-up and delivery of car bodies at the lift station in the workshop without using pallets, so as to facilitate the transfer of the car bodies to, for example, a measurement center for checking their dimensions, and to conveniently return the car bodies to the warehouse after the inspection for transportation to other sites. Utility Model Content

[0005] In view of the above problems, the present application aims to provide a trolley mechanism for cooperating with a lift to pick up and transport vehicle bodies, which can solve the above problems existing in the prior art.

[0006] To this end, the present application is directed to a trolley mechanism, characterized in that the trolley mechanism includes a movable trolley and a ground fixing system, the ground fixing system is used to cooperate with the trolley to position the trolley and lock the trolley in place, so as to cooperate with a lift to pick up and transport the vehicle body.

[0007] By using the dolly mechanism according to the present application, it is convenient to receive a vehicle body from a lift or to deliver the vehicle body to a lift without a pallet.

[0008] If the trolley mechanism according to the present application is arranged in an existing lift station, two vehicle retrieval methods can be realized: retrieval using the original tray; and retrieval without a tray using a trolley.

[0009] In any case, this allows for greater flexibility in the handling of the car bodies prior to final assembly.

[0010] Advantageously, the ground fixing system comprises: a longitudinally extending guide rail for guiding the trolley to move longitudinally along the guide rail; a mechanical limit device configured to cooperate with the trolley so as to limit the longitudinal position of the trolley when the trolley moves longitudinally along the guide rail; and a locking device arranged in a spaced relationship from the mechanical limit device in the longitudinal front of the mechanical limit device, configured to cooperate with the limited trolley to lock the trolley in place.

[0011] Advantageously, the trolley comprises: a frame; at least four rollers arranged in pairs at the bottom of the frame for enabling the trolley to move with the aid of the rollers; a body positioning device arranged on the upper part of the frame and configured to reversibly retain the body on the trolley by cooperating with a complementary positioning device on the bottom of the body; a stopper arranged on the frame and configured to cooperate with a mechanical limiter fixed on the ground to stop the trolley from moving forward longitudinally; a connecting rod locking assembly arranged on the frame and configured to cooperate with a locking device fixed on the ground to lock the trolley in place.

[0012] Advantageously, the trolley mechanism further comprises an electrical safety unit for ensuring that the trolley is correctly positioned longitudinally and that the locking device locks the trolley in place.

[0013] Advantageously, the ground fixing system comprises two parallel guide rails, and the locking device and the mechanical limiting device are arranged between the two guide rails near the front ends of the guide rails.

[0014] Advantageously, the frame of the trolley is a double-layer structure, including an upper frame and a lower frame, each of which is composed of two longitudinal beams and a plurality of cross beams connecting the corresponding two longitudinal beams, and the upper frame and the lower frame are connected together by a plurality of columns; the four rollers are all universal wheels, fixed in pairs at the lower part of the two longitudinal beams of the lower frame near the front end and rear end of the two longitudinal beams of the lower frame.

[0015] Advantageously, the plurality of cross beams of the upper frame are fixed to the lower part of the two longitudinal beams of the upper frame, and include at least: an upper front cross beam, located near the longitudinal front end of the upper frame, and when the trolley is engaged with the ground fixing system, the upper front cross beam is close to the locking device; an upper rear cross beam, longitudinally opposite to the upper front cross beam, and located near the longitudinal rear end of the upper frame; and at least two other cross beams, located between the upper front cross beam and the upper rear cross beam.

[0016] Advantageously, the trolley comprises two body positioning devices, which are arranged on the upper frame and spaced apart longitudinally by a certain distance, wherein each body positioning device comprises: a transverse bracket, which is fixed to the top of the two longitudinal beams of the upper frame through its two transverse ends; two clamp-type transverse retaining members, respectively located at one of the two transverse ends of the transverse bracket, for clamping the corresponding transverse retaining members on the bottom of the body to laterally retain the body; a U-shaped groove-type longitudinal retaining member, which is located between the two clamp-type transverse retaining members on the transverse bracket, and is used to longitudinally retain the body by being clamped into the U-shaped groove by the corresponding tubular longitudinal retaining members on the bottom of the body.

[0017] Advantageously, the two transverse brackets of the two vehicle body positioning devices are vertically opposite to the corresponding two other transverse beams of the upper frame.

[0018] Advantageously, the multiple cross beams of the lower frame include at least a lower front cross beam, which is located near the longitudinal front end of the lower frame and is offset longitudinally rearward relative to the upper front cross beam of the upper frame. When the trolley is engaged with the ground fixing system, the lower front cross beam will be close to the mechanical limit device; the stop member is in the form of a stop block, which is arranged on the lower front cross beam and is oriented so that when the trolley is engaged with the ground fixing system, the stop member faces the mechanical limit device and is on the longitudinal rear side of the mechanical limit device.

[0019] Advantageously, the connecting rod locking assembly is arranged transversely between the two longitudinal beams of the upper frame, and includes: a connecting rod, which extends longitudinally from the rear end to the front end above the upper frame cross beam and through the space between the transverse bracket of the vehicle body positioning device and the opposite upper frame cross beam, the rear end of the connecting rod extends longitudinally rearward beyond the upper rear cross beam, and the front end of the connecting rod extends longitudinally forward beyond the upper front cross beam; an operating handle, which can be pivotally connected to the rear end of the connecting rod on the one hand, and can be pivotally connected to the upper rear cross beam on the other hand; a locking hook, which can be pivotally connected to the front end of the connecting rod on the one hand, and can be pivotally connected to the upper front cross beam on the other hand.

[0020] Advantageously, the operating handle comprises: a transversely extending crossbar portion; a hand grip fixed to the transverse outer end of the crossbar portion and extending longitudinally rearward; a pivotally connected portion extending longitudinally forward, generally L-shaped, comprising a first branch and a second branch, the first branch being fixedly connected to the transverse inner end of the crossbar portion at a free end, the operating handle being pivotally connected to the upper rear crossbeam at the junction of the first branch and the second branch, and the operating handle being pivotally connected to the rear end of the connecting rod at the free end of the second branch.

[0021] Advantageously, the connecting rod locking assembly further comprises a connecting rod reset spring, one end of which is fixedly connected to the upper rear cross beam and the other end of which is fixedly connected to the rear end of the connecting rod pivotally movable with the operating handle, for resetting the connecting rod when the operating handle is released.

[0022] Advantageously, the lock hook member includes: a hook head with a lock slot for cooperating with the locking device; a hook tail opposite to the hook head, configured to be pivotally connected to the upper front cross beam; and an ear portion extending upward in the opposite direction of the lock slot, configured to be pivotally connected to the front end of the connecting rod.

[0023] Advantageously, the locking device comprises: two side plates; a middle plate connecting the two side plates; a cylindrical hook rod, which is arranged between the upper parts of the two side plates at intervals above the middle plate; a base, which is fixedly connected to the bottom of the two side plates and the middle plate, and is used to fix the locking device on the ground between the two guide rails near the front end of the guide rail, so that the hook rod extends laterally relative to the guide rail, so that when the trolley is longitudinally limited by means of a mechanical limit device, the hook rod is roughly below the lock hook member, thereby allowing the hook head to be lifted by pressing down the operating handle, and then releasing the operating handle so that the hook head falls down and is locked on the hook rod through the lock groove.

[0024] Advantageously, the electrical safety unit comprises at least two sensors arranged on the locking device, wherein: the first sensor is used to detect whether the lock hook is locked to the hook rod, and the first sensor is arranged on the upper longitudinal front surface of the middle plate of the locking device close to the hook rod; the second sensor is arranged on the locking device in the opposite direction to the first sensor, and is used to detect whether the trolley is correctly positioned longitudinally.

[0025] Advantageously, the locking device further comprises a support arm, which is fixed to the upper longitudinal rear surface of the middle plate through its front end and is close to one of the two side plates, and the support arm extends longitudinally rearward to its rear end, and a second sensor is fixed to the rear end of the support arm on the transverse outer side of the support arm, for detecting whether the trolley is correctly positioned longitudinally. When correctly positioned longitudinally, the upper front crossbeam of the trolley will be above the second sensor and vertically opposite to it.

[0026] Advantageously, the mechanical limiting device comprises a vertical plate, a buffer block, a support plate and a base, wherein the buffer block is fixed to the upper longitudinal rear surface of the vertical plate and extends backward to be blocked against the stopper of the trolley, and the support plate is fixed to the longitudinal front surface of the vertical plate facing the locking device at the longitudinal front; the base of the mechanical limiting device is fixedly connected to the bottom of the vertical plate and the support plate, and is used to fix the mechanical limiting device to the ground.

[0027] Advantageously, the buffer block is cylindrical; there are two support plates, which are fixed on the longitudinal front surface of the vertical plate at two lateral sides of the vertical plate respectively.

[0028] Advantageously, the trolley is provided with a first handrail at least on the operating handle side.

[0029] Advantageously, the trolley is provided with a second handrail on the lock hook side opposite to the first handrail.

[0030] Advantageously, each guide rail is flared at the inlet end on the longitudinal rear side.

[0031] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] By reading the detailed description of the embodiments given in a non-limiting manner in conjunction with the accompanying drawings below, other objects, features, details and advantages of the present application will be more clearly reflected. The accompanying drawings are only for the purpose of illustrating preferred embodiments and are not considered to be limitations of the present application. In addition, the various features of the drawings discussed below are not necessarily drawn to scale. The sizes of the various features and elements in the drawings may be enlarged or reduced to more clearly illustrate the embodiments of the present application. Moreover, in all drawings, the same reference numerals refer to similar or identical elements throughout the drawings and their descriptions. In the drawings:

[0033] Figure 1 It is an overall perspective view of a trolley mechanism according to an embodiment of the present application.

[0034] Figure 2 yes Figure 1 The enlarged schematic diagram of the longitudinal front part of the trolley mechanism intercepted in the shown box particularly shows the front body positioning device on the trolley and the locking device and mechanical limit device on the ground.

[0035] Figure 3 A perspective view of a link locking assembly on a trolley that locks the trolley to a locking device fixed to the ground is shown, with other parts of the trolley mechanism omitted for clarity.

[0036] Figure 4 Shown separately in perspective Figure 1 , 3 The operating handle of the linkage locking assembly is visible.

[0037] Figure 5 The connection seat for pivotable connection is shown separately and exemplarily in a perspective view.

[0038] Figure 6 Shown separately in perspective Figure 1-2 Mechanical limit devices of the ground fixing system can be seen in Figure 2.

[0039] Figure 7 Shown separately in perspective Figure 1-2 The locking device of the ground fixing system and the sensors on it can be seen. DETAILED DESCRIPTION

[0040] Each illustrative embodiment of the present application is described below. In this specification, for the sake of explanation only, each system, structure and device are schematically depicted in the accompanying drawings, but all features of the actual system, structure and device are not described, such as well-known functions or structures are not described in detail, to avoid unnecessary details that make the present application unclear. Of course, it should be understood that in any practical application, many specific implementation decisions need to be made to achieve the specific goals of the developer or user, and it is necessary to comply with system-related and industry-related restrictions, and these specific goals may vary with the actual application. In addition, it should be understood that although such specific implementation decisions are complex and time-consuming, this is a routine task for those of ordinary skill in the art who benefit from the present application.

[0041] The terms and phrases used herein should be understood and interpreted as having a meaning consistent with the understanding of such terms and phrases by those skilled in the relevant art. Consistent usage of a term or phrase herein is not intended to imply a special definition of the term or phrase, i.e., a definition that is different from the ordinary and customary meaning as understood by those skilled in the art. For terms or phrases that are intended to have a special meaning, i.e., a meaning that is different from that understood by those skilled in the art, such special definition will be explicitly listed in the specification as a definition, directly and unambiguously giving the special definition of the term or phrase.

[0042] Unless required by content, throughout the following description and claims, the word "include" and variations such as "comprises" are to be interpreted in an open, inclusive sense, that is, as "including but not limited to."

[0043] Throughout the description of this specification, reference to the terms "an embodiment", "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. Thus, the phrases "in one embodiment" or "in an embodiment" appearing in different places throughout this specification do not necessarily all refer to the same embodiment. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0044] As used in this specification and the appended claims, the indefinite articles "a" and "an" in the singular and the definite articles "the" include one or more referents unless expressly specified and limited otherwise. It should also be noted that the term "or" generally includes "and / or" in its meaning, unless expressly specified and limited otherwise. For the purposes of this description, a phrase in the form of "A or B" means "(A), (B) or (A and B)". For the purposes of this description, a phrase in the form of "at least one of A, B or C" means "(A), (B), (C), (A and B), (A and C), (B and C) or (A, B and C)". In addition, the character " / " in this document generally indicates that the objects before and after are in an "or" relationship.

[0045] In the description of the embodiments of the present application, the terms "first", "second", etc. are only used to distinguish different objects and shall not be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary and secondary relationship of the indicated technical features.

[0046] In the description of the embodiments of the present application, the term "plurality" refers to more than two (including two).

[0047] In the description of the embodiments of the present application, terms such as "middle", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0048] In this application, unless otherwise clearly specified and limited, the terms "install", "connect", "couple", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0049] Specific embodiments of the present application will be explained in detail below with reference to the accompanying drawings.

[0050] Reference Figure 1, a trolley mechanism A according to an embodiment of the present application can be seen. The trolley mechanism A can cooperate with a lift (not shown in the figure) to allow the trolley to directly take a car body, such as a white body or a painted car body, from the lift without using a pallet, or allow the lift to directly take a car body from the trolley.

[0051] Advantageously, therefore, such a trolley mechanism can be arranged, for example, in a conventional lift station. In a conventional lift station, the lift is raised / lowered vertically as appropriate. Typically, the lift station is provided with a number of posts on the ground for placing pallets, and when the lift carrying the car body enters the station from above, it is necessary to first place a special car receiving pallet on these posts, then lower the lift to drop the car body onto the pallet and lock it to the pallet, and then remove the car body by means of a forklift using the pallet. As mentioned above, since the white body or the painted body with the pallet cannot be transferred to the measuring center for testing, it is not possible to carry out some tests on the car body before final assembly. These car bodies can currently only be tested after they have been transferred to the final assembly station.

[0052] To this end, the trolley mechanism according to the present application can be added to the conventional lift station, specifically, it can be set in the space defined by the pillars of the lift station for supporting the pallet, so that the lift can directly drop the car body onto the trolley without the pallet, and then move the car body to the required position such as the measurement center with the help of the trolley. After the car body is tested in the measurement center, it can also be transported to the car body storage CBS with the trolley to be transferred to other stations.

[0053] like Figure 1 The trolley mechanism A shown mainly comprises: a movable part, i.e., a movable trolley 1; and a part fixed to the ground, i.e., a ground fixing system 2, which is used to cooperate with the trolley 1 to correctly position the trolley 1 longitudinally and laterally and lock the trolley in place, so that the trolley 1 is vertically aligned with the elevator above (not shown in the figure), so that when the trolley is picked up from the elevator, the trolley carried by the elevator can directly fall onto the trolley and remain positioned on the trolley, or conversely, the elevator can directly take the vehicle body that is positioned on the trolley away from the trolley.

[0054] See also Figure 1 The ground fixing system 2 includes a guide rail fixed to the ground, which includes two parallel guide rails 21, and the guide rails are configured to guide the trolley 1 to move along them.

[0055] Note that, in particular, for clarity of description, Figure 1The coordinate system (L, T, V) is shown in . The direction in which the guide rail extends, i.e., its length direction, is defined as the longitudinal direction L. Therefore, the two guide rails 21 extend longitudinally to guide the trolley to move longitudinally. The direction from one guide rail 21 to another guide rail 21 is called the transverse direction T, which is perpendicular to the longitudinal direction L, and the vertical direction V is perpendicular to both L and T. Therefore, the so-called front (part, side, square, etc.) and rear (part, side, square, etc.) are defined relative to the longitudinal direction L, the so-called left and right are defined relative to the transverse direction T, and the so-called up and down are defined relative to the vertical direction. In addition, the side facing the inside of the guide rail is called the inside and the side facing the outside of the guide rail is called the outside. As described later, these direction definitions are also applicable to the trolley 1 that will be coordinated with the ground fixing system 2.

[0056] in addition Figure 1 The front and rear along the longitudinal direction are also schematically shown. Figure 1 The left is along the longitudinal front, and Figure 1 The right side is along the longitudinal rear.

[0057] The ground fixing system 2 also includes a locking device 22 and a mechanical limiting device 23. Figure 1 As shown, a locking device 22 and a mechanical limiting device 23 fixed to the ground are arranged between the two guide rails 21 near the front end of the guide rails.

[0058] The mechanical stopper 23 is configured to cooperate with the trolley 1 so as to limit the trolley longitudinally when the trolley moves longitudinally along the guide rail 21. This stopper enables the trolley 1 to be initially positioned longitudinally relative to the guide rail. In addition, since the trolley 1 moves along two transversely opposite guide rails 21, the trolley is positioned transversely by the two guide rails, thereby ensuring that the trolley itself is straight in the longitudinal direction without being skewed left or right.

[0059] The locking device 22 is arranged in front of the mechanical limiting device 23 in the longitudinal direction and is spaced apart from the mechanical limiting device 23 by a distance, and is configured to cooperate with the limited trolley 1 to lock the trolley in place.

[0060] To further explain the locking device 22 and the mechanical stopper 23 of the ground fixing system 2, reference is first made to Figure 1 The cart 1 is described in detail as follows.

[0061] The trolley 1 is a frame structure. Advantageously, the frame of the trolley is a double-layer structure, including an upper frame 11 and a lower frame 12, each of which is composed of two longitudinal beams and a plurality of cross beams connecting the corresponding two longitudinal beams, and the upper frame and the lower frame are connected by a plurality of columns.

[0062] As shown in the figure, the longitudinal beams, cross beams and columns of the trolley frame are advantageously made of hollow profiles. Here, the profile is polyhedral, and a plurality of holes are opened on the surface of the profile to help reduce its weight. Of course, other suitable shapes of rods such as square tubes can also be considered.

[0063] like Figure 1 As shown, the plurality of transverse beams of the upper frame 11 are fixed to the lower parts of the two longitudinal beams 111 and 112 thereof, for example, by welding or by fixing the transverse beams and the longitudinal beams together with screws through connecting members as shown in the figure.

[0064] The multiple cross beams of the upper frame 11 include at least: an upper front cross beam 113, which is near the longitudinal front end of the upper frame 11, and when the trolley 1 is matched with the ground fixing system 2, the upper front cross beam 113 is close to the locking device 22 on the ground; an upper rear cross beam 114, which is longitudinally opposite to the upper front cross beam 113 and is near the longitudinal rear end of the upper frame; and at least two other cross beams located between the upper front cross beam and the upper rear cross beam. Figure 1 Here three other cross beams 115, 116 and 117 are shown. Of course, more other cross beams can be provided to strengthen the trolley frame.

[0065] The crossbeam of the lower frame 12 is Figure 1 1 and 2 are exemplarily shown in the figure. Of course, a larger number of lower cross beams can also be provided. Unlike the cross beams of the upper frame, the cross beams 123 and 124 of the lower frame are fixed between the two longitudinal beams 121 and 122 of the lower frame instead of the lower part thereof.

[0066] See here Figure 1 It can be seen that the lower front cross beam 123 is located near the longitudinal front end of the lower frame and is offset longitudinally backward relative to the upper front cross beam 113 of the upper frame. When the trolley 1 is matched with the ground fixing system 2, the lower front cross beam 123 will be close to the mechanical stop device 23.

[0067] In addition, here, for example, six columns connecting the upper frame 11 and the lower frame 12 are symmetrically arranged on both sides of the horizontal direction. Figure 1 From the lateral side facing the middle, it can be seen that the two middle columns 131 and 132 are supported between the corresponding longitudinal beams of the upper and lower frames, and the two side columns 133 and 134, 135 and 136 on the longitudinal sides of the two middle columns 131 and 132 are Figure 1 It can be seen in the figure that each side column is fixed to the lateral inner side of the longitudinal beam of the lower frame at the lower part, and vertically supports the lower part of the corresponding cross beam of the upper frame through its top.

[0068] Likewise, the number of columns and their supporting positions can vary depending on the situation.

[0069] The double-layered trolley constructed in this way can support a vehicle body weighing up to 750 kilograms.

[0070] The trolley 1 further comprises at least four rollers, for example, four rollers are shown in the figure. These four rollers are, for example, universal wheels, arranged in pairs at the bottom of the frame, specifically fixed at the lower part of the two longitudinal beams 121, 122 of the lower frame 12 near the front and rear ends of the longitudinal beams 121, 122, for facilitating the trolley to move on the guide rail or the ground with the help of the rollers. Figure 1 The two rollers, one in front and one behind, on the facing lateral sides of the cart are indicated by the reference numerals 141 and 142.

[0071] Advantageously, the two rollers on the longitudinal rear side may be provided with brakes so that, for example, the trolley can be stopped temporarily when it leaves the ground fixing system and moves to another suitable position.

[0072] Another advantage is that Figure 1 It can be seen that the two guide rails 21 are designed to be trumpet-shaped at the entrance end for the trolley to enter on the longitudinal rear side, so as to facilitate guiding the trolley 1 to enter the guide rails 21.

[0073] The trolley 1 also includes a body positioning device, which is arranged on the upper part of the upper frame 11 and is configured to reversibly retain the body on the trolley by cooperating with complementary positioning devices on the bottom of the body, not shown in the figure. That is, when the trolley 1 is accurately positioned and locked in place by the ground fixing system 2, the trolley 1 is exactly aligned vertically with the lift above, not shown, and thus with the body carried by the lift, and the body falls, and its positioning device retains the body on the trolley by directly engaging the complementary positioning device on the trolley without manual intervention. The same is true in reverse, when the trolley carrying the body is advanced on the guide rails and locked in place, the lift is lowered and the body is directly removed from the trolley without manual intervention.

[0074] More precisely, the dolly 1 comprises two body locating devices 15 arranged on the upper frame 11 and spaced longitudinally a certain distance apart, one of which is called a front body locating device and the other a rear body locating device. This certain distance is set to correspond to the spacing distance of two complementary locating devices on the bottom of the body. If the bottom dimensions of all the bodies received are the same, the two body locating devices 15 can be fixedly arranged on the upper frame.

[0075] Of course, if it is necessary to accommodate vehicle bodies with different bottom sizes, it is also possible to consider movably arranging the two vehicle body positioning devices on the upper frame so that the longitudinal spacing between them can be adjusted according to the different bottom sizes of the vehicle bodies.

[0076] Here, the description is made on the condition that they are fixedly arranged on the upper frame.

[0077] See for clarity from Figure 1 Cut out from the box Figure 2 Each vehicle body positioning device 15 includes: a transverse bracket 151, which is transversely fixed to the top of the two longitudinal beams of the upper frame 11 through its two transverse ends; two clamp-type transverse retaining members 152, which are respectively located at one of the two transverse ends of the transverse bracket 151, and are used to clamp the corresponding transverse retaining members (not shown in the figure) on the bottom of the vehicle body to be transversely clamped to laterally retain the vehicle body; a U-shaped groove-type longitudinal retaining member 153, which is located between the two clamp-type transverse retaining members 152 on the transverse bracket, and is used to longitudinally retain the vehicle body by being inserted into the U-shaped groove through the corresponding tubular longitudinal retaining members on the bottom of the vehicle body.

[0078] Advantageously, if Figure 1-2 As shown, the cross section of the transverse bracket 151 in the longitudinal direction is in the shape of an inverted T, and is fixed to the longitudinal beams 111, 112 of the upper frame through the horizontal branch of the inverted T. The clamp-type transverse retaining members 152 are each formed, for example, in the following manner: two separate clips are generally rectangular, and are fixed in pairs, for example, by screws, on both sides of the longitudinal direction of the vertical branch of the inverted T-shape, thereby forming a clamp. It is also advantageous that the two clips can be bent away from each other at a certain angle at the upper part, for example, to form a wide mouth, which is conducive to guiding the corresponding transverse retaining member of the complementary positioning device on the vehicle body to fall into and be clamped into the clamp formed in this way.

[0079] A U-shaped groove-type longitudinal retaining member 153 is positioned between the two clamp-type transverse retaining members 152, advantageously in the middle thereof. Figure 1-2 The longitudinal retainer 153 is in the form of a single piece, and has a rectangular overall shape, with an upwardly open U-shaped groove, and is fixed to a longitudinal side, here the longitudinal front side, of the vertical branch of the inverted T-shape through the lower part below the U-shaped groove, for example, by screws. In addition, the upper parts of the two side wings of the U-shaped groove can also be bent forward longitudinally on the one hand, and on the other hand, the lateral inner side thereof is also inclined to form a similar wide mouth to guide the tubular longitudinal retainer on the vehicle body into the groove.

[0080] Of course, the transverse and longitudinal retaining members 152 , 153 of the two front and rear vehicle body positioning devices 15 are correspondingly arranged in alignment along the longitudinal direction.

[0081] The U-shaped grooves of the longitudinal retaining members 153 in the middle of the front and rear vehicle body positioning devices 15 respectively receive two longitudinally extending tubular retaining members arranged on the bottom of the vehicle body, and the tubular retaining members are snapped into the U-shaped grooves so that the vehicle body is held on the trolley in the longitudinal direction.

[0082] In addition, Figure 1-2As shown, advantageously, the two transverse brackets 151 of the front and rear vehicle body positioning devices are vertically opposed to the corresponding two other transverse beams 115 and 116 of the upper frame 11 fixed to the lower part of the longitudinal beam thereof, respectively, so that the load-bearing capacity can be enhanced.

[0083] See also Figure 2 , from which the lower front crossbeam 123 of the lower frame can be more clearly seen. A stopper 1231, here in the form of a stopper, is provided on the lower front crossbeam 123, which is oriented so that when the trolley 1 is engaged with the ground fixing system 2, the stopper 1231 faces the mechanical stopper 23 and is at the longitudinal rear side of the mechanical stopper, so as to cooperate with the mechanical stopper to stop the trolley longitudinally forward, thereby enabling the trolley to be initially positioned in the longitudinal direction. The mechanical stopper 23 will be described in detail below.

[0084] In addition, see Figure 1-3 The trolley 1 further comprises a connecting rod locking assembly 16, which is configured to cooperate with the locking device 23 to lock the trolley.

[0085] See especially Figure 3 For the sake of clarity, the figure only shows the connecting rod locking assembly 16 and the locking device 23 fixed on the ground that cooperates with it.

[0086] Combination Figure 1 and Figure 3 The connecting rod locking assembly 16 is arranged transversely between the two longitudinal beams 111 and 121 of the upper frame 11, and includes: a connecting rod 161, which extends longitudinally from the rear end to the front end above the upper frame cross beam and through the space between the transverse bracket 151 of the vehicle body positioning device 15 and the opposite cross beams 115 and 116, the rear end of the connecting rod extends longitudinally backward beyond the upper rear cross beam 114, and the front end of the connecting rod extends longitudinally forward beyond the upper front cross beam 113; an operating handle 162, which can be pivotally connected to the rear end of the connecting rod on the one hand, and can be pivotally connected to the upper rear cross beam 114 on the other hand; a lock hook 163, which can be pivotally connected to the front end of the connecting rod on the one hand, and can be pivotally connected to the upper front cross beam 113 on the other hand.

[0087] The connecting rod 161 and the locking hook 163 are preferably arranged in the middle of the two longitudinal beams 111 , 121 .

[0088] The connecting rod 161 is, for example, a slender flat steel member.

[0089] Combination Figure 1 , 3-4, it can be seen that the operating handle 162 here includes, for example: a transversely extending crossbar portion 1621, for example, in a cylindrical shape; a hand grip 1622, fixed to the transverse outer end of the crossbar portion 1621 and extending longitudinally backward, which may be, for example, roughly cylindrical, and preferably also covered with a jacket; and a pivot connection portion 1623, which generally extends longitudinally forward. Figure 4 As shown, the pivot connection portion 1623 is roughly L-shaped here, including a first branch 171 and a second branch 172, the first branch 171 is fixedly connected at its free end to the lateral inner end of the cross bar portion 1621, the operating handle 162 is pivotally connected to the upper rear cross beam 114 at the junction of the first branch 171 and the second branch 172, and the operating handle 162 is pivotally connected to the rear end of the connecting rod at the free end of the second branch 172.

[0090] In order to pivotally connect the operating handle 162 to the upper rear cross beam 114 and the rear end of the connecting rod, Figure 4 As can be seen in the figure, a through hole is provided at the free end of the second branch 172, and another through hole is provided at the junction of the first and second branches. The operating handle and the connecting rod are pivotally connected together by passing a bolt through the through hole at the free end of the second branch and the corresponding through hole at the rear end of the connecting rod and locking it with a nut. In addition, it is advantageous that in order to pivotally connect the operating handle to the upper rear cross beam 114, for example, a protrusion can be fixedly provided on the rear part of the upper rear cross beam, for example, in the middle of the rear part, and then the operating handle can be connected to the upper rear cross beam 114. Figure 5 The connecting seat 173 shown is fixed on the protrusion, and then the right-angled joint of the first branch 171 and the second branch 172 of the pivot connection part 1623 is inserted between the two lugs of the connecting seat 173, and a bolt is passed through the corresponding through holes on the lug and the pivot connection part and locked with a nut.

[0091] Thus, when the trolley 1 moves forward longitudinally along the guide rail 21 until the stopper 1231 abuts against the mechanical limit device 23, the staff presses down the operating handle 162 to lift the lock hook 163 upward, and releases the operating handle 162 so that the lock hook 163 falls down to hook the locking device 22 to lock the trolley in place. Figure 3 But in Figure 1-2 In the embodiment, the lock hook 163 has not yet completely hooked the locking device, specifically the hook rod, which will be further described later.

[0092] Here as shown in the figures, the hand grip of the operating handle 162 is located on a lateral side of the trolley 1. Of course, it can also be arranged on the opposite lateral side of the trolley 1.

[0093] Preferably, the connecting rod locking assembly 16 may also include a connecting rod reset spring not shown in the figure, one end of which is fixedly connected to the upper rear cross beam 114 and the other end is fixedly connected to the rear end of the connecting rod pivotally movable with the operating handle 162, so as to reset the connecting rod 161 when the operating handle is released.

[0094] But this return spring is not necessary. When the staff releases the downward pressure applied to the operating handle 162, due to the pivoting movable connection and gravity coordination, even if there is no return spring, the connecting rod can also be reset, thereby the lock hook part at its front end also falls accordingly.

[0095] In addition, Figure 4 As shown, a protrusion 173 is additionally provided on the second branch 172 of the pivot connection 1623, which extends on the side opposite to the first branch 171, and is arranged so that in the rest state, the protrusion 173 rests on the convex block of the upper rear cross beam 114 and the upper part of the connecting seat 173. The protrusion 173 is also not necessary.

[0096] For the lock hook member 163, as Figure 2 It is shown as comprising: a hook head 1631 with a locking groove 1632 for cooperating with the locking device 22; a hook tail 1633 opposite to the hook head, configured to be pivotally connected to the upper front cross beam 113; an ear 1634, extending upward in the opposite direction of the locking groove 1632, configured to be pivotally connected to the front end of the connecting rod.

[0097] Here, the pivotal connection between the ear 1634 of the lock hook and the front end of the connecting rod, and the pivotal connection between the hook tail 1633 and the upper front cross beam 113 are similar to the pivotal connection between the operating handle and the connecting rod and the upper rear cross beam. However, the lock hook is directly pivotally connected to the front end of the connecting rod through its ear 1634, and is also pivotally connected to the front end of the connecting rod through its hook tail 1633. Figure 5 A connecting seat of the type shown is pivotally connected to the upper front crossbeam 113 .

[0098] Of course, this is just an example, and other ways to achieve pivotal connection are also conceivable.

[0099] The ground fixing system 2 of the trolley mechanism according to the present application will be further described below with reference to the relevant drawings.

[0100] As mentioned above, in addition to the two longitudinal guide rails 21 fixed to the ground, the ground fixing system 2 also includes a locking device 22 and a mechanical limit device 23 arranged between the two guide rails 21 near the front end of the guide rails. The locking device 22 is arranged longitudinally in front of the mechanical limit device 23 and separated from the mechanical limit device by a distance. This is because when the trolley moves forward longitudinally along the guide rail, it must first be stopped by the stopper 1231 and the mechanical limit device 23 on the ground, so as to achieve the longitudinal rough positioning of the trolley 1.

[0101] See also Figure 6 In an exemplary manner, the mechanical stopper 23 includes a vertical plate 231, a buffer block 232, a support plate 233 and a base 234. The buffer block 232 is cylindrical in the figure, fixed to a surface of the vertical plate, here, the upper part of the longitudinal rear surface and extending backward to stop against the stopper (see Figure 1-2 The support plate 233 is fixed to the longitudinal front surface of the vertical plate 231, and is longitudinally opposite to the cylindrical buffer block 232, so as to face the locking device 22 in the longitudinal front. Figure 1-2 There are two support plates 233 here, which are fixed on the longitudinal front surface of the vertical plate at both lateral sides of the vertical plate. Figure 6 One of the support plates 233 can be seen in the figure, and the support plate is, for example, roughly in the shape of a right triangle. The base 234 of the mechanical stopper 23 is fixedly connected to the bottom of the vertical plate 231 and the support plate 233, and is used to fix the mechanical stopper 23 to the ground, for example, by screws visible in the figure. The triangular support plate 233 is fixed to the vertical plate 231 and the base 234 respectively by two right-angled sides.

[0102] As for the locking device 22, combined with Figure 1-3 , see especially Figure 7 , it can be seen that the locking device includes in an exemplary manner: two side plates 221; an intermediate plate 222 connecting the two side plates 221; a hook rod 223, for example a cylindrical shape, which is spaced a distance above the intermediate plate 222 and arranged between the upper parts of the two side plates 221; a base 224, which is fixedly connected to the bottom of the two side plates and the intermediate plate, and is used to fix the locking device 22 to the ground between the two guide rails, for example by bolts, close to the front end of the guide rail, so that the hook rod 223 extends transversely relative to the guide rail 21, so that when the trolley 1 is longitudinally limited by the mechanical limit device 23, the hook rod 223 is roughly below the lock hook member 163, thereby allowing the hook head 1631 to be lifted by pressing the operating handle 162, and then the hook head falls when the operating handle is released, and is locked on the hook rod 223 through the locking groove 1632.

[0103] For this embodiment, the locking device 22 is obviously higher vertically than the mechanical limit device 23, because the locking device 22 cooperates with the connecting rod locking assembly 16 above the upper frame of the trolley by means of the hook rod 223, while the mechanical limit device 23 cooperates with the lower front cross beam 123 of the lower frame of the trolley through the buffer block 232.

[0104] It should also be noted that, usually during operation, when the staff observes that the trolley is stopped by the mechanical stopper 23 on the ground, they can act on the operating handle 162 to make the lock hook in the longitudinal front cooperate with the hook rod 223 of the locking device. However, for safety reasons, the staff will not immediately operate the lift to lower, because it is not certain that the hook groove of the hook head clamps the hook rod and the trolley is truly in place longitudinally. Therefore, it is necessary to check the locking state of the lock hook and the longitudinal position of the trolley.

[0105] For example, in one case, when the trolley is stopped by the longitudinal stopper while moving forward along the guide rail, the trolley is only roughly positioned forward longitudinally and may not have reached the precise longitudinal front stop position, but at this time, when the connecting rod locking assembly 16 is operated, the lock groove of the lock hook member may still be fixed on the hook rod; in another case, the trolley is stopped on the guide rail and stops at the precise longitudinal front upper position, but when the connecting rod locking assembly is operated, the locking member may fall down due to a malfunction but not be fixed on the hook rod, so the trolley is at risk of moving. At this time, even if the lift is lowered, the lift cannot accurately align the trolley vertically, so that the body it carries cannot be accurately placed on the body positioning device of the trolley, or the body cannot be removed from the trolley because the trolley will deviate longitudinally relative to the lift.

[0106] To this end, the trolley mechanism is advantageously provided with an electrical safety unit for ensuring that the locking hook is locked to the hook rod and the trolley is correctly positioned longitudinally. This electrical safety unit makes it easier to perform the above-mentioned safety check, because the trolley is long in the longitudinal direction or is affected by the surrounding environment, such as when the trolley mechanism is arranged in a traditional lift station, it is difficult for a person to directly approach to check the positioning and locking status of the trolley relative to the guide rail.

[0107] The electrical safety unit comprises at least two sensors 181, 182 arranged on the locking device 22. Figure 2 and Figure 7 The first sensor 181 shown is arranged near the hook rod 223 on the upper longitudinal front surface of the middle plate 222 of the locking device, and is used to detect whether the lock hook is locked to the hook rod; and the second sensor 182 is set on the locking device 22 in the opposite direction of the first sensor 181, and is used to detect whether the trolley, or more specifically its upper front cross beam 113, is correctly positioned longitudinally.

[0108] The locking device 22 further comprises Figure 2-3 The support arm 225 can be seen in the figure. The support arm 225 is fixed to the upper longitudinal rear surface of the middle plate 222 and close to one of the two side plates through the front end. The support arm extends longitudinally backward to its rear end. The second sensor 182 is fixed to the rear end of the support arm on the lateral outer side of the support arm. Figure 7, wherein the support arm 225 carrying the second sensor 182 is blocked and cannot be seen. The second sensor 182 is configured to detect whether the trolley is correctly positioned longitudinally. If the trolley is correctly positioned longitudinally, the upper front crossbeam 113 of the trolley 1 will be above the second sensor 118 and vertically opposite to it, and can therefore be detected by it.

[0109] These sensors are connected to an HMI screen (human-machine interface screen) via cables not shown in the figure, and the status of these sensors can be intuitively observed from the screen. Only when the status of the two sensors on the screen is displayed as green at the same time (that is, the trolley is accurately in place longitudinally and the trolley is locked in place and will not move), the staff will click the corresponding key on the screen to use the PLC (Programmable Logic Controller) to control the elevator to fall, so as to drop the body onto the trolley or take the body from the trolley. If at least one of the two sensors 181 and 182 is not displayed as green, even if the corresponding key on the screen is clicked, the PLC will not control the action of the elevator. The staff needs to check the locking state of the lock hook and / or the trolley and accurately position the longitudinal position of its crossbeam to eliminate potential faults. In other words, the PLC will pick up / deliver the body based on the signals of these two sensors.

[0110] Finally, to facilitate the movement of the cart, whether on rails or on the ground, e.g. Figure 1 As shown, the trolley 1 is provided with a handrail 19 on the side of the operating handle 162, that is, on the longitudinal rear side.

[0111] It is still necessary to point out here that, relative to the ground fixing system 2, the side of the operating handle 162 of the trolley is defined as the longitudinal rear side, and the opposite side of the lock hook member that cooperates with the locking device 22 and the mechanical limit device 23 of the ground fixing system is defined as the longitudinal front side. It is also necessary to point out that when the vehicle body is located on the trolley, the front of the vehicle is usually oriented toward the longitudinal front side.

[0112] See also Figure 1 For example, the two longitudinal beams 111, 112 of the upper frame can extend longitudinally backward beyond the hand grip of the operating handle 162, and then bend upward, and the ends of the bent longitudinal beams are transversely connected with a handrail rod to form the handrail 19. Of course, the bent longitudinal beam portion can be replaced by a separate bent rod. In addition, a reinforcing beam can be provided between the two longitudinal beam portions extending horizontally at the rear side of the operating handle to strengthen the formed handrail 19.

[0113] It is also advantageous that the trolley 1 can also be provided with another handrail on the side of the lock hook member opposite to the handrail 19. This method is not shown in the figure. With two opposite handrails, the trolley can be pushed at the longitudinal front and rear sides at the same time, which is more convenient to move, especially when a heavy vehicle body is loaded on the trolley.

[0114] The following briefly describes the working process of the trolley mechanism according to the present application.

[0115] When it is necessary to conduct quality inspection on the vehicle body, such as measuring the size of the vehicle body, detecting heat dissipation, deformation, etc., before the vehicle body is sent to the final assembly, the staff pushes the unloaded trolley 1 to the elevator station, so that it enters the guide rail 21 and moves forward on the guide rail 21 until it stops due to the mechanical limit device 23 on the ground hitting the stopper 1231 of the trolley. The staff then presses down the operating handle 16 on the longitudinal rear side where the entrance end of the guide rail is located to lift the lock hook member on the longitudinal front side, and then the staff releases the operating handle, the connecting rod resets, and the lock hook member falls and locks on the hook rod of the locking device. Then the staff observes the screen. If the screen shows that both sensors are green, the work button on the screen is clicked, and the PLC lowers the elevator, so that the vehicle body it carries falls accurately on the trolley and is held by the vehicle body positioning device on the trolley. Then the staff pushes the trolley off the guide rail and sends it to the measurement center. After inspection at the measurement center, the trolley can transport the car body to the storage warehouse, or transport the car body to another elevator station equipped with a similar trolley mechanism. In a similar way, the trolley carrying the car body is accurately positioned and locked on the guide rails. The PLC lowers the elevator through the screen to remove the car body from the trolley.

[0116] In fact, the present application may include any feature or feature combination or generalization disclosed herein, whether implicitly or explicitly, without being limited to any of the limited scopes listed above. Any elements, features and / or structural arrangements described herein may be combined in any suitable manner.

[0117] The specific embodiments disclosed above are exemplary only, and it will be apparent to those skilled in the art who have the benefit of the teachings herein that the present application may be modified and implemented in different but equivalent ways. For example, the above method steps may be performed in a different order. In addition, the details of the construction or design shown herein are not limited except as described in the following claims. It is therefore apparent that the specific embodiments disclosed above may be changed and modified, and all such variations are considered to fall within the scope and spirit of the present application. Therefore, the protection sought herein is set forth in the appended claims.

Claims

1. A trolley mechanism, characterized in that: The trolley mechanism comprises a movable trolley and a ground fixing system. The ground fixing system is used to cooperate with the trolley to position the trolley and lock the trolley in place, so as to cooperate with the lift to pick up and transport the vehicle body.

2. The trolley mechanism according to claim 1, characterized in that: The ground fixing system includes: a longitudinally extending guide rail for guiding the trolley to move longitudinally along the guide rail; a mechanical limit device, configured to cooperate with the trolley so as to limit the longitudinal position of the trolley when the trolley moves longitudinally along the guide rail; a locking device, arranged in front of the mechanical limit device and spaced apart from the mechanical limit device, configured to cooperate with the limited trolley to lock the trolley in place.

3. The trolley mechanism according to claim 2, characterized in that: The trolley mechanism also includes an electrical safety unit for ensuring the correct longitudinal positioning of the trolley and a locking device to lock the trolley in place.

4. The trolley mechanism according to claim 3, characterized in that: The trolley comprises: a frame; at least four rollers arranged in pairs at the bottom of the frame for enabling the trolley to move with the aid of the rollers; a body positioning device arranged on the upper portion of the frame and configured to reversibly retain the body on the trolley by cooperating with a complementary positioning device on the bottom of the body; a stopper arranged on the frame and configured to cooperate with a mechanical limiter fixed on the ground to stop the trolley from moving forward longitudinally; and a connecting rod locking assembly arranged on the frame and configured to cooperate with a locking device fixed on the ground to lock the trolley in place.

5. The trolley mechanism according to claim 4, characterized in that: The ground fixing system comprises two parallel guide rails, and a locking device and a mechanical limiting device are arranged between the two guide rails near the front ends of the guide rails.

6. The trolley mechanism according to claim 5, characterized in that: The frame of the trolley is a double-layer structure, including an upper frame and a lower frame. The upper frame and the lower frame are each composed of two longitudinal beams and a plurality of cross beams connecting the corresponding two longitudinal beams. The upper frame and the lower frame are connected together by a plurality of columns; the four rollers are all universal wheels, which are fixed in pairs at the lower part of the two longitudinal beams of the lower frame near the front end and the rear end of the two longitudinal beams of the lower frame.

7. The trolley mechanism according to claim 6, characterized in that: The multiple cross beams of the upper frame are fixed to the lower parts of the two longitudinal beams of the upper frame, and at least include: an upper front cross beam, which is near the longitudinal front end of the upper frame, and when the trolley is matched with the ground fixing system, the upper front cross beam is close to the locking device; an upper rear cross beam, which is longitudinally opposite to the upper front cross beam and is near the longitudinal rear end of the upper frame; at least two other cross beams are located between the upper front cross beam and the upper rear cross beam.

8. The trolley mechanism according to claim 7, characterized in that: The trolley includes two body positioning devices, which are arranged on the upper frame and spaced apart a certain distance longitudinally, wherein each body positioning device includes: a transverse bracket, which is fixed to the top of the two longitudinal beams of the upper frame through its two transverse ends; two clamp-type transverse retaining members, which are respectively located at one of the two transverse ends of the transverse bracket and are used to clamp the corresponding transverse retaining members on the bottom of the body to be transversely held so as to hold the body laterally; a U-shaped groove-type longitudinal retaining member, which is located between the two clamp-type transverse retaining members on the transverse bracket and is used to clamp the corresponding tubular longitudinal retaining members on the bottom of the body into the U-shaped groove to hold the body longitudinally.

9. The trolley mechanism according to claim 8, characterized in that: The two transverse brackets of the two vehicle body positioning devices are respectively vertically opposite to the corresponding two other transverse beams of the upper frame.

10. The trolley mechanism according to claim 9, characterized in that: The multiple cross beams of the lower frame include at least a lower front cross beam, which is located near the longitudinal front end of the lower frame and is offset longitudinally rearward relative to the upper front cross beam of the upper frame. When the trolley is engaged with the ground fixing system, the lower front cross beam will be close to the mechanical limit device; the stop member is in the form of a stop block, which is arranged on the lower front cross beam and is oriented so that when the trolley is engaged with the ground fixing system, the stop member faces the mechanical limit device and is on the longitudinal rear side of the mechanical limit device.

11. The trolley mechanism according to claim 10, characterized in that: The connecting rod locking assembly is arranged transversely between the two longitudinal beams of the upper frame, and includes: a connecting rod, which extends longitudinally from the rear end to the front end above the upper frame cross beam and passes through the space between the transverse bracket of the vehicle body positioning device and the opposite upper frame cross beam, the rear end of the connecting rod extends longitudinally rearward beyond the upper rear cross beam, and the front end of the connecting rod extends longitudinally forward beyond the upper front cross beam; an operating handle, which can be pivotally connected to the rear end of the connecting rod on the one hand, and can be pivotally connected to the upper rear cross beam on the other hand; a locking hook, which can be pivotally connected to the front end of the connecting rod on the one hand, and can be pivotally connected to the upper front cross beam on the other hand.

12. The trolley mechanism according to claim 11, characterized in that: The operating handle includes: a transversely extending crossbar portion; a hand grip fixed to the transverse outer end of the crossbar portion and extending longitudinally rearward; a pivotally connected portion extending longitudinally forward, roughly L-shaped, including a first branch and a second branch, the first branch being fixedly connected to the transverse inner end of the crossbar portion at the free end, the operating handle being pivotally connected to the upper rear crossbeam at the junction of the first branch and the second branch, and the operating handle being pivotally connected to the rear end of the connecting rod at the free end of the second branch.

13. The trolley mechanism according to claim 12, characterized in that: The connecting rod locking assembly also includes a connecting rod reset spring, one end of which is fixedly connected to the upper rear cross beam and the other end is fixedly connected to the rear end of the connecting rod pivotally movable with the operating handle, so as to reset the connecting rod when the operating handle is released.

14. The trolley mechanism according to claim 13, characterized in that: The lock hook member includes: a hook head with a lock slot for cooperating with the locking device; a hook tail opposite to the hook head, configured to be pivotally connected to the upper front cross beam; and an ear portion extending upward opposite to the lock slot, configured to be pivotally connected to the front end of the connecting rod.

15. The trolley mechanism according to claim 14, characterized in that: The locking device includes: two side plates; an intermediate plate connecting the two side plates; a cylindrical hook rod, which is arranged between the upper parts of the two side plates at intervals above the intermediate plate; a base, which is fixedly connected to the bottom of the two side plates and the intermediate plate, and is used to fix the locking device on the ground between the two guide rails near the front end of the guide rail, so that the hook rod extends transversely relative to the guide rail, so that when the trolley is longitudinally limited by the mechanical limiting device, the hook rod is roughly below the lock hook member, thereby allowing the hook head to be lifted by pressing down the operating handle, and then releasing the operating handle so that the hook head falls down and is locked on the hook rod through the lock groove.

16. The trolley mechanism according to claim 15, characterized in that: The electrical safety unit includes at least two sensors arranged on the locking device, wherein: the first sensor is used to detect whether the lock hook is locked on the hook rod, and the first sensor is arranged on the upper longitudinal front surface of the middle plate of the locking device close to the hook rod; the second sensor is arranged on the locking device in the opposite direction to the first sensor, and is used to detect whether the trolley is correctly positioned longitudinally.

17. The trolley mechanism according to claim 16, characterized in that: The locking device further comprises a supporting arm, which is fixed to the upper longitudinal rear surface of the middle plate through its front end and is close to one of the two side plates, and the supporting arm extends longitudinally rearward to its rear end, and a second sensor is fixed to the rear end of the supporting arm on the transverse outer side of the supporting arm, and is used to detect whether the trolley is correctly positioned longitudinally. When correctly positioned longitudinally, the upper front crossbeam of the trolley will be above the second sensor and vertically opposite to it.

18. The trolley mechanism according to claim 17, characterized in that: The mechanical limit device includes a vertical plate, a buffer block, a support plate and a base, wherein the buffer block is fixed to the upper part of the longitudinal rear surface of the vertical plate and extends backward to be blocked against the stopper of the trolley, and the support plate is fixed to the longitudinal front surface of the vertical plate facing the locking device in the longitudinal front; the base of the mechanical limit device is fixedly connected to the bottom of the vertical plate and the support plate, and is used to fix the mechanical limit device on the ground.

19. The trolley mechanism according to claim 18, characterized in that: The buffer block is cylindrical; there are two support plates, which are respectively fixed on the longitudinal front surface of the vertical plate at the transverse sides of the vertical plate.

20. The trolley mechanism according to any one of claims 11 to 19, characterized in that: The trolley is provided with a first handrail at least on the side of the operating handle.

21. The trolley mechanism according to claim 20, characterized in that: The trolley is provided with a second handrail opposite to the first handrail on the side of the lock hook.

22. The trolley mechanism according to any one of claims 2 to 19, characterized in that: Each guide rail is flared at the inlet end on the longitudinal rear side.

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