CN108569640B - Lifting fork frame and aviation food vehicle with same - Google Patents

Lifting fork frame and aviation food vehicle with same Download PDF

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Publication number
CN108569640B
CN108569640B CN201711433518.4A CN201711433518A CN108569640B CN 108569640 B CN108569640 B CN 108569640B CN 201711433518 A CN201711433518 A CN 201711433518A CN 108569640 B CN108569640 B CN 108569640B
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China
Prior art keywords
interval
fork
current value
controller
lifting
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CN201711433518.4A
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Chinese (zh)
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CN108569640A (en
Inventor
何春栋
高永胜
余晓军
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Xinfa Airport Equipment Ltd
Langfang CIMC Airport Support Ltd
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China International Marine Containers Group Co Ltd
Xinfa Airport Equipment Ltd
CIMC Tianda Holdings Shenzhen Co Ltd
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Application filed by China International Marine Containers Group Co Ltd, Xinfa Airport Equipment Ltd, CIMC Tianda Holdings Shenzhen Co Ltd filed Critical China International Marine Containers Group Co Ltd
Priority to CN201711433518.4A priority Critical patent/CN108569640B/en
Publication of CN108569640A publication Critical patent/CN108569640A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F7/00—Lifting frames, e.g. for lifting vehicles; Platform lifts
    • B66F7/06—Lifting frames, e.g. for lifting vehicles; Platform lifts with platforms supported by levers for vertical movement
    • B66F7/08—Lifting frames, e.g. for lifting vehicles; Platform lifts with platforms supported by levers for vertical movement hydraulically or pneumatically operated
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64F—GROUND OR AIRCRAFT-CARRIER-DECK INSTALLATIONS SPECIALLY ADAPTED FOR USE IN CONNECTION WITH AIRCRAFT; DESIGNING, MANUFACTURING, ASSEMBLING, CLEANING, MAINTAINING OR REPAIRING AIRCRAFT, NOT OTHERWISE PROVIDED FOR; HANDLING, TRANSPORTING, TESTING OR INSPECTING AIRCRAFT COMPONENTS, NOT OTHERWISE PROVIDED FOR
    • B64F1/00—Ground or aircraft-carrier-deck installations
    • B64F1/32—Ground or aircraft-carrier-deck installations for handling freight
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F7/00—Lifting frames, e.g. for lifting vehicles; Platform lifts
    • B66F7/06—Lifting frames, e.g. for lifting vehicles; Platform lifts with platforms supported by levers for vertical movement
    • B66F7/065—Scissor linkages, i.e. X-configuration
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
    • F15B11/046—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed depending on the position of the working member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/17—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors using two or more pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/06—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with two or more servomotors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/02—Servomotor systems with programme control derived from a store or timing device; Control devices therefor

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Analytical Chemistry (AREA)
  • Chemical & Material Sciences (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Forklifts And Lifting Vehicles (AREA)
  • Vehicle Body Suspensions (AREA)

Abstract

The invention discloses a lifting fork frame and an aviation food vehicle with the same. The controller provides current with corresponding current value to the proportional electromagnet according to a plurality of height intervals in the lifting fork frame stroke, thereby controlling the hydraulic flow supplied to the hydraulic system and further controlling the ascending or descending speed of the lifting fork frame lifting carriage. The invention realizes the control of the controller on the lifting speed according to different heights by adopting the design that the controller adjusts the current of the proportional electromagnet of the proportional throttle valve. The invention can make the speed of the carriage in the moving process transition smoothly, avoid the damage of the goods in the carriage and improve the comfort of the working personnel in the carriage.

Description

Lifting fork frame and aviation food vehicle with same
Technical Field
The invention relates to the technical field of special lifting equipment for vehicles, in particular to a lifting fork frame and an aviation food vehicle with the same.
Background
The aviation food vehicle belongs to a special vehicle for an airport and is specially used for catering of a passenger plane. Due to the wide variety of passenger aircraft, the air food carts for catering are generally classified into general type air food carts suitable for general passenger aircraft and a380 air food carts suitable for large passenger aircraft such as a380 airplane. The maximum lifting height of a common aviation food carriage body is 6.2m, the carriage body is butted with an airplane cabin door through a four-way platform to complete an airplane, and the height of the airplane cabin door which can be served by the food vehicle is generally below 6.2 m. The maximum lifting height of the A380 aviation food carriage body reaches 8.1m, and when a meal is prepared for the A380 airplane, the lifting height exceeds 6.2 m.
In the initial height of the aviation food vehicle in the descending process, the shaking and the non-uniform motion of the carriage in the initial period of descending from the highest position are caused by the change of the load and the fixed value of the back pressure of the hydraulic circuit. The solution of the prior art to the above problem is to use a 10-path switch type electromagnetic directional valve to control the lifting of the carriage. Based on the existing design, the ascending speed of the carriage is determined by the rotating speed of the engine throttle after acceleration, the carriage is basically not adjustable, the oil return throttling speed regulation or double-speed throttling speed regulation is used during descending, only 1 or 2 descending speeds can be set, and the problem of shaking during descending of the box body is difficult to solve.
Moreover, when the A380 aviation food cart is catering to an A380 airplane, the ground clearance of the floor of the carriage reaches 8.1m, the whole carriage moves forwards by 3m, the gravity center of the whole cart is obviously changed, and the stability of the whole cart is a problem which needs to be considered. The whole weight of the airplane is obviously changed in the catering process, the ground clearance of the cabin door is obviously reduced, the ground clearance of the four-way platform of the food car butted with the cabin door is reduced along with the motion, and the seamless butt joint of the four-way platform and the cabin door can be ensured. Meanwhile, due to the manufacturing and assembling precision of the fork frame and the leakage of a hydraulic lock of a control fork frame lifting oil cylinder, the A380 aviation food vehicle lifting fork frame can sink slowly automatically when the lifting fork frame stops at a certain height, the sinking amount in the height direction can reach 30mm/h when the lifting fork frame stops at the height of 6.1m, and the automatic falling of the fork frame is a common problem of the hydraulic system of the existing food vehicle.
Disclosure of Invention
It is a primary object of the present invention to overcome at least one of the above-mentioned disadvantages of the prior art and to provide an elevating fork capable of providing more than three lowering speeds.
It is another primary object of the present invention to overcome at least one of the above-mentioned disadvantages of the prior art and to provide an aircraft food cart having the above-mentioned lift fork and suitable for use in a380 or similar large aircraft.
In order to achieve the purpose, the invention adopts the following technical scheme:
according to one aspect of the present invention, there is provided a lift fork disposed between a frame and a bed of a truck. The lift fork includes a fork carriage assembly, a hydraulic system for driving the fork carriage assembly to lift, and a controller for controlling the hydraulic system. The system trunk of the hydraulic system is provided with a proportional reversing valve, and the controller is connected to the proportional reversing valve and used for controlling the current value of the current input to the proportional electromagnet of the proportional reversing valve. The controller provides current with corresponding current value to the proportional electromagnet according to a plurality of height intervals in the lifting fork frame stroke, so that the hydraulic flow supplied to the hydraulic system is controlled, and the lifting fork frame lifting speed of the carriage is controlled.
According to one embodiment of the invention, the plurality of height intervals in the stroke of the lifting fork frame at least comprise a high interval, a stable interval and a low interval from high to low. When the lifting fork is positioned in the high-position interval, the stable interval and the low-position interval, the current values of the current given to the proportional electromagnet by the controller are respectively a first current value, a second current value and a third current value, and the third current value is larger than the first current value and smaller than the second current value.
According to one embodiment of the invention, the lifting assembly comprises a double-stage lifting hydraulic cylinder, and the plurality of height intervals in the stroke of the lifting fork frame further comprise a stage change interval when the first-stage cylinder is changed from the second-stage cylinder. When the lifting fork is located in the gear shifting interval, the current value of the current given to the proportional electromagnet by the controller is the first current value.
According to one embodiment of the present invention, the transition interval is between the high-order interval and the plateau interval. Or the stage change interval is between the stable interval and the low-order interval. Or the stage changing interval is contained in the stable interval, the stable interval comprises a first stable interval and a second stable interval, and the height of the stage changing interval is smaller than the first stable interval and larger than the second stable interval.
According to one embodiment of the invention, when the lifting fork ascends and is still at a height, and the lifting fork automatically descends, the controller controls the hydraulic system to drive the lifting fork to ascend back to the original height, and the current value of the current supplied to the proportional electromagnet by the controller during the ascending back is the first current value.
According to one embodiment of the invention, the controller is a PLC controller.
According to one embodiment of the present invention, a rotation angle encoder is provided on a rotation shaft of the elevation fork to detect an angle at which the fork of the elevation fork rotates. Wherein the controller is connected to the rotation angle encoder to calculate the height interval of the lifting fork according to the angle.
According to another aspect of the invention, an aviation food cart is provided that includes a cart frame and a cart compartment. Wherein, the aviation food vehicle also comprises the lifting fork frame of the embodiment.
According to one embodiment of the invention, the aviation food vehicle further comprises a four-way platform, the four-way platform is arranged at one end of the carriage close to the door of the airplane, and a detection switch is arranged on the four-way platform; the controller is connected to the detection switch, a rotary encoder is used for detecting a fork angle of the lifting fork when the lifting fork ascends and descends, the height position of the carriage is obtained through calculation by the controller, the detection switch is triggered when the carriage ascends and is abutted to an airplane and the airplane descends to the height of the detection switch relative to the carriage, the controller controls the lifting fork to descend, and the current value of the current given to the proportional electromagnet by the controller is the first current value.
According to one embodiment of the present invention, the plurality of height sections in the lift fork stroke include the high section, the first plateau section, the staging section, the second plateau section, and the low section, and when the current values of the currents supplied to the proportional electromagnet by the controller are a first current value, a second current value, and a third current value, respectively, the high section is 6.8m to 8.1m, the first plateau section is 5.5m to 6.8m, the staging section is 5.3m to 5.5m, the second plateau section is 3.4m to 5.3m, and the low section is 3.4m or less; and/or the first current value is between 0.2A and 0.4A, the second current value is between 0.9A and 1A, and the third current value is between 0.5A and 0.6A.
According to the technical scheme, the lifting fork frame and the aviation food vehicle with the lifting fork frame have the advantages and positive effects that:
according to the lifting fork frame and the aviation food vehicle, the controller is adopted to regulate the current of the proportional electromagnet of the proportional throttle valve, so that the controller can control the lifting speed according to different heights. Through the design, the speed of the carriage in the moving process can be smoothly transited, the goods in the carriage are prevented from being damaged, and the comfort level of workers in the carriage is improved. In addition, the invention can flexibly adjust the moving speed of the fork frame aiming at the problems of shaking, uneven speed and the like of the lifting fork frame in the moving process.
Drawings
Various objects, features and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the invention, when considered in conjunction with the accompanying drawings. The drawings are merely exemplary of the invention and are not necessarily drawn to scale. In the drawings, like reference characters designate the same or similar parts throughout the different views. Wherein:
fig. 1 is a schematic view illustrating a construction of an elevating fork according to an exemplary embodiment;
fig. 2 is a bottom view of the elevation fork carriage shown in fig. 1;
FIG. 3 is a schematic diagram of a hydraulic system of the elevation fork carriage shown in FIG. 1;
fig. 4 is a control schematic diagram of the elevation fork shown in fig. 1.
Wherein the reference numerals are as follows:
100. a lifting fork frame;
111. a left front leg;
112. a left rear leg;
120. a rotating shaft;
130. a rotation angle encoder;
140. a two-stage lifting hydraulic cylinder;
141. a primary cylinder;
142. a secondary cylinder;
210. a system trunk;
211. a proportional directional valve;
212. a main lifting cylinder;
220. a transverse telescopic branch;
221. the left front supporting leg transversely stretches out and draws back the oil cylinder;
222. a left rear supporting leg transversely stretches the oil cylinder;
223. a right front supporting leg transversely telescopic oil cylinder;
224. the right rear supporting leg transversely stretches out and draws back the oil cylinder;
230. a lifting branch;
231. a left front supporting leg lifting oil cylinder;
232. the left rear supporting leg lifts the oil cylinder;
233. a right front supporting leg lifting oil cylinder;
234. the right rear supporting leg lifts the oil cylinder;
240. a chassis hydraulic power unit.
Detailed Description
Exemplary embodiments that embody features and advantages of the invention are described in detail below. It is to be understood that the invention is capable of other and different embodiments and its several details are capable of modification without departing from the scope of the invention, and that the description and drawings are accordingly to be regarded as illustrative in nature and not as restrictive.
In the following description of various exemplary embodiments of the invention, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration various exemplary structures, systems, and steps in which aspects of the invention may be practiced. It is to be understood that other specific arrangements of parts, structures, example devices, systems, and steps may be utilized and structural and functional modifications may be made without departing from the scope of the present invention. Also, while the terms "upper end," "lower end," "between," "side," and the like may be used in this specification to describe various example features and elements of the invention, these terms are used herein for convenience only, e.g., in accordance with the orientation of the examples set forth in the figures. Nothing in this specification should be construed as requiring a specific three dimensional orientation of structures in order to fall within the scope of the invention.
Lift fork embodiment
Referring to fig. 1, a schematic view of the construction of an elevating fork capable of embodying the principles of the present invention is representatively illustrated in fig. 1. In the exemplary embodiment, the present invention is directed to a fork lift which is applicable to an aviation food car. Those skilled in the art will readily appreciate that numerous modifications, additions, substitutions, deletions, or other changes may be made to the specific embodiments described below for applying the lifting fork to other types of vehicles or other types of equipment, and such changes are within the scope of the lifting fork concept set forth herein.
As shown in fig. 1, in the present embodiment, the lifting fork 100 according to the present invention may be used to be disposed between a frame and a car of a truck, thereby lifting the car with respect to the frame. Specifically, the elevation fork carriage 100 mainly includes a fork carriage assembly, a hydraulic system driving the elevation of the fork carriage assembly, and a controller controlling the hydraulic system. Referring to fig. 2 to 4 in combination, fig. 2 representatively illustrates a bottom view of an elevator fork 100 which can embody principles of the present invention; a hydraulic system schematic of a lift fork 100 that can embody principles of the present invention is representatively illustrated in fig. 3; a control schematic of an elevator fork 100 that can embody principles of the present invention is representatively illustrated in fig. 4. Hereinafter, the structure, connection manner and functional relationship of the main components of the elevating fork 100 according to the present invention will be described in detail with reference to the above drawings.
As shown in fig. 1 and 2, in the present embodiment, the fork carriage assembly may refer to the related design of the existing elevation fork carriage. Specifically, the fork carriage assembly mainly comprises a front leg and a rear leg which are arranged in a crossed manner, and the front leg is rotatably connected with the middle part of the rear leg. The front leg comprises a left front leg 111 and a right front leg arranged in parallel, and the rear leg comprises a left rear leg 112 and a right rear leg arranged in parallel. In which, referring to the prior art design of the lift fork 100 on a vehicle such as an aviation food car, one ends of the front left leg 111 and the front right leg are rotatably connected to a front end of a frame of the aviation food car through a rotating shaft, and the other ends of the front left leg 111 and the front right leg are rotatably and slidably connected to a bottom of a cabin of the aviation food car. One end of the left rear leg 112 and the right rear leg is rotatably and slidably connected to the frame of the aero-food vehicle, and the other end of the left rear leg 112 and the right rear leg is rotatably and slidably connected to the front end of the bottom of the vehicle cabin. A main lifting oil cylinder 212 is arranged between the front supporting leg and the rear supporting leg, the cylinder body of the main lifting oil cylinder 212 is rotatably connected to the lower half part of the front supporting leg, and the cylinder rod is rotatably connected to the upper half part of the rear supporting leg. In other embodiments, the fork carriage assembly may refer to other structural designs of the existing lifting fork, and is not limited to this embodiment.
As shown in fig. 3, in the present embodiment, most of the structure of the hydraulic system may refer to the related system design of the hydraulic system of the existing elevation fork carriage. Specifically, the hydraulic system supplies oil to the cylinders via the system trunk 210 and the system branches to control the operation states of the cylinders by being powered by a chassis hydraulic power unit 240 mounted on the frame of the aircraft food cart. The system trunk 210 and each system branch are connected in parallel, and the system branches mainly include a transverse telescopic branch 220 and a lifting branch 230. The system trunk 210 is used for supplying oil to the main lifting oil cylinder 212, the transverse telescopic branch 220 is used for supplying oil to the left front leg transverse telescopic oil cylinder 221, the left rear leg transverse telescopic oil cylinder 222, the right front leg transverse telescopic oil cylinder 223 and the right rear leg transverse telescopic oil cylinder 224, and the lifting branch 230 is used for supplying oil to the left front leg lifting oil cylinder 231, the left rear leg lifting oil cylinder 232, the right front leg lifting oil cylinder 233 and the right rear leg lifting oil cylinder 234. In other embodiments, the above structure of the hydraulic system may refer to other system designs of the hydraulic system of the existing lift fork, and is not limited to this embodiment.
As shown in fig. 3, in the present embodiment, the system trunk 210 is provided with a proportional directional valve 211, and a controller is connected to the proportional directional valve 211 for controlling the current value of the current of the proportional electromagnet input to the proportional directional valve 211. Specifically, the controller can control the hydraulic flow rate supplied to each cylinder (e.g., the main lift cylinder 212) of the hydraulic system by applying current of a corresponding current value to the proportional solenoid according to a plurality of height intervals in the stroke of the elevation fork 100, thereby controlling the speed at which the elevation fork 100 lifts the car up or down.
Further, in the present embodiment, the plurality of height sections in the stroke of the elevation fork 100 may include at least a high section, a plateau section, and a low section from high to low. Specifically, the high-order section is an initial height range in which the vehicle is likely to shake when the vehicle is raised to the high-order position and is ready to be lowered, the steady section is a height range in which the vehicle is steadily lowered, and the low-order section is a height range in which the vehicle is lowered to the low-order position. When the lifting fork 100 is in a high-position interval, a stable interval and a low-position interval, the current values of the current supplied to the proportional electromagnet by the controller are respectively a first current value, a second current value and a third current value, and the third current value is greater than the first current value and less than the second current value.
With the above-described design, when the lift fork 100 lifts the car up to the high position and prepares to descend, a chattering phenomenon is easily generated in the high position section. At this time, the controller supplies a first current value to the proportional electromagnet of the proportional directional valve 211, so as to control the valve port of the proportional directional valve 211 to be closed (i.e. a small part is opened), so that the carriage is slowly lowered in the high-level area, and the carriage is prevented from shaking. When the carriage is lowered to a stable region by the lifting fork 100, the current given to the proportional electromagnet of the proportional directional valve 211 by the controller is a second larger current value, so that the valve port of the proportional directional valve 211 is controlled to be fully opened (or to have a larger opening), the carriage is rapidly lowered in the stable region, and the carriage lowering efficiency is ensured. When the carriage is lowered to the low-level region by the lifting fork 100, the current supplied to the proportional electromagnet of the proportional directional valve 211 by the controller is a third current value which is relatively small, so that the valve port of the proportional directional valve 211 is controlled to be approximately half-open, the carriage is lowered slowly in the low-level region, accidents are avoided, and the safety of operation and maintenance personnel is ensured.
As described above, the controller may supply current of corresponding current values to the proportional solenoid of the proportional directional valve 211 according to a plurality of height sections of the elevation fork 100 during the stroke thereof, thereby controlling the opening degree of the valve port of the proportional directional valve 211, that is, controlling the hydraulic flow supplied to the system trunk 210 of the hydraulic system, and thus controlling the elevation fork 100 to lift the car at corresponding speeds during different height sections of the stroke thereof. In other embodiments, the plurality of different height sections in the stroke of the elevation fork 100 are not limited to the above-described height sections in the present embodiment, and may be flexibly defined according to actual demands for the elevation fork 100 to lift the car. Moreover, the current values of the currents corresponding to the different height intervals can be adjusted according to the requirement for the lifting speed, and the embodiment is not limited thereto.
Further, in the present embodiment, when the main lift cylinder 212 is a dual-stage lift cylinder 140, which is a common type of lift fork in the prior art, the plurality of height sections of the lift fork 100 may at least include a stage-changing section, that is, a height section corresponding to the stage-changing of the first-stage cylinder 141 and the second-stage cylinder 142 of the dual-stage lift cylinder 140. Wherein, when the elevation fork 100 is in the above-mentioned shift interval, the current value of the current supplied from the controller to the proportional solenoid of the proportional directional valve 211 may be the first current value. With the above design, when the fork carriage 100 lowers the car to the height section corresponding to the stage change between the first stage cylinder 141 and the second stage cylinder 142 of the two-stage lift cylinder 140, the box body will shake significantly. At this time, the controller supplies a first current value to the proportional electromagnet of the proportional directional valve 211, so as to control the valve port of the proportional directional valve 211 to be closed (i.e. a small part is opened), so that the carriage is slowly lowered in the step change interval, and the shaking phenomenon of the carriage is relieved.
Depending on the specific structure of the lift fork 100 and the two-stage lift cylinder 140, the shift interval may be between the high interval and the steady interval, or between the steady interval and the low interval, or may be included in the steady interval. When the step change interval is within the stable interval, the stable interval further comprises a first stable interval and a second stable interval, and the height of the step change interval is smaller than the first stable interval and larger than the second stable interval.
Further, in the present embodiment, when the elevation fork 100 lifts the car and is stationary at a height, and the elevation fork 100 is automatically lowered, the controller may control the hydraulic system to drive the elevation fork 100 to be lifted back to the original height, and the current value of the current supplied from the controller to the proportional solenoid of the proportional directional valve 211 during the lifting process is preferably a first current value. Specifically, in combination with the application environment of the aviation food cart in the present embodiment, the above situation may specifically include a phenomenon that the cart slowly and automatically descends due to leakage from the main lift cylinder 212 when the cart is at a certain height and the four-way platform is in an extended state.
Further, in the present embodiment, the controller may preferably be a PLC controller.
As shown in fig. 1, in the present embodiment, a rotation angle encoder 130 is further provided on a rotation shaft of the elevation fork 100 to detect a fork rotation angle of the elevation fork 100. The controller is connected to the rotation angle encoder 130, so as to calculate the height of the lifting fork 100 according to the angle measured by the rotation angle encoder 130, and thus, the current height is compared to what height interval (for example, a high interval, a first stable interval, a step change interval, a second stable interval, and a low interval in the present embodiment) preset in the controller, and the controller supplies the current with the corresponding current value (for example, the first current value, the second current value, and the third current value in the present embodiment) to the proportional electromagnet of the proportional directional valve 211 according to the different height intervals. In other embodiments, other elements or methods may be used instead of the rotation angle encoder 130 in this embodiment to detect the fork rotation angle of the elevation fork 100, so as to calculate the height of the elevation fork 100, or other elements or methods may be used to directly detect the height of the elevation fork 100, which is not limited in this embodiment.
Further, considering that the elevation fork 100 is affected by various factors in a real working environment, the above-mentioned height intervals are actually changed to some extent. Therefore, in the present embodiment, the controller can determine in which height section the elevation fork 100 is located by detecting the shaking of the elevation fork 100 during the operation of the elevation fork 100 through the relevant elements, thereby giving a current of a corresponding current value. For example, the rotation angle encoder 130 may be used to detect the angular change rate of the elevation fork 100, and accordingly calculate whether the elevation fork 100 (car) shakes or a specific degree of shaking.
Specifically, in the stationary section, the lift fork 100 normally lifts the car without causing a chattering phenomenon, i.e., the angular velocity of the rotating shaft (the change in the rotation angle detected by the rotation angle encoder 130 per unit time) is constant or gradually changed (continuously increased or continuously decreased, which is mainly a transition process in which the spool is gradually switched from one position to another position after the proportional directional valve 211 receives an electric signal) for a period of time (e.g., 3 to 4 s). When the shaking phenomenon occurs, the angular speed of the rotating shaft is frequently fluctuated within a period of time, and the shaking phenomenon can be considered to occur when the angular speed of the carriage is lowered more than a certain number of times (for example, 3 times) by detecting the number of times that the angular speed of the rotating shaft is less than 0.015rad/s (the angular speed value is only used for reference and can be flexibly adjusted according to the lowering speed requirements of different types of carriages) within the period of time (for example, 3-4 s). If the judgments exist the shake condition, the controller outputs the current of the first current value (or the second current value) to control the valve port of the reversing valve to be closed, and the carriage is prevented from continuously shaking when descending. When the current duration of the first current value output by the controller exceeds 5s, the current value of the output current of the controller is increased to a second current value, the valve port of the proportional directional valve 211 is controlled to be fully opened, and the carriage descends rapidly. In addition, for the two descending processes of the high-order section → the stable section (or the first stable section → the grade-changing section → the second stable section) and the stable section → the low-order section, the judgment can be further performed by combining the relevant information of the height position of the carriage.
Based on the above exemplary description, the control principle of the elevating fork according to the present invention can be described with reference to fig. 4. Wherein, the rotation angle encoder inputs angle signal to the PLC controller, and the PLC controller can learn the fork frame angle of lift fork frame with this, further can calculate according to the fork frame angle and obtain the high position that corresponding carriage is located, can calculate according to the fork frame angle simultaneously and obtain the angular velocity of lift fork frame. And when the operator presses a micro button, the micro button inputs a micro adjusting signal to the PLC. The PLC controller provides current with corresponding current value to the proportional electromagnet of the proportional directional valve according to different current motion states or height positions of the lifting fork frame, so that the opening degree (such as small-part opening, half opening or full opening) of a valve port of the proportional directional valve is controlled, and the lifting speed of the lifting fork frame is further controlled.
It should be noted herein that the lift fork illustrated in the drawings and described in the present specification is only one example of the many kinds of lift forks that can employ the principles of the present invention. It should be clearly understood that the principles of the present invention are in no way limited to any of the details of the lift fork or any component of the lift fork shown in the drawings or described in this specification.
Implementation mode of aviation food vehicle
In the present embodiment, the aviation food cart proposed by the present invention is explained taking an aviation food cart applied to an a380 airplane as an example. Those skilled in the art will readily appreciate that numerous modifications, additions, substitutions, deletions, or other changes may be made to the specific embodiments described below in order to adapt the design of an aircraft food cart for use with other types of aircraft or other types of vehicle equipment, and still fall within the scope of the principles of the proposed aircraft food cart.
In the embodiment, the aviation food cart provided by the invention mainly comprises a cart frame, a cart compartment and the lifting fork provided by the invention.
Further, in this embodiment, the aero-food vehicle further comprises a four-way platform. Specifically, the carriage is arranged on a four-direction platform, the lifting fork frame is arranged between the frame and the four-direction platform, and the four-direction platform is provided with a detection switch. When the carriage rises and is in butt joint with an airplane and the airplane descends to the height of the detection switch relative to the carriage, the detection switch is triggered, the controller controls the lifting fork frame to descend, the current value of the current given by the controller to the proportional electromagnet is a first current value, namely a small part of a valve port of the proportional reversing valve is opened, and the carriage is controlled to slowly descend to the same height of the four-way platform and the cabin door, so that the descending fine adjustment of the carriage height is realized.
Further, in the present embodiment, based on the design that the plurality of height intervals in the travel of the lifting fork includes a high interval, a first stable interval, a staging interval, a second stable interval and a low interval, and the current values of the currents given to the proportional electromagnet by the controller are respectively corresponding first current value, second current value and third current value, in combination with parameters such as the cabin door height of the a380 aircraft and parameters such as the specific working height of the aviation food vehicle suitable for the a380 aircraft, the high interval may be between 6.8m and 8.1m, the first stable interval may be between 5.5m and 6.8m, the staging interval may be between 5.3m and 5.5m, the second stable interval may be between 3.4m and 5.3m, and the low interval may be less than 3.4 m. The first current value can be 0.2A-0.4A, the second current value can be 0.9A-1A, and the third current value can be 0.5A-0.6A. The above-described action of responding to the slow automatic lowering of the car due to the hydraulic pressure leakage may be performed when the car is automatically lowered to a height exceeding 0.1m to 0.2m by the controller.
It should be noted that the specific height range of each height interval and the specific value of each current value can be flexibly adjusted according to different types of application environments (such as airplane models and aircraft food cart structures), and the present embodiment is not limited thereto.
It should be noted herein that the aerial food carts shown in the drawings and described in this specification are but one example of the wide variety of aerial food carts that can employ the principles of the present invention. It should be clearly understood that the principles of the present invention are in no way limited to any of the details of the aerial food vehicle or any of the components of the aerial food vehicle shown in the drawings or described in this specification.
In summary, the lifting fork and the aviation food vehicle provided by the invention realize the control of the controller on the lifting speed according to different heights by adopting the design that the controller adjusts the current of the proportional electromagnet of the proportional throttle valve. Through the design, the speed of the carriage in the moving process can be smoothly transited, the goods in the carriage are prevented from being damaged, and the comfort level of workers in the carriage is improved. In addition, the invention can flexibly adjust the moving speed of the fork frame aiming at the problems of shaking, uneven speed and the like of the lifting fork frame in the moving process.
Exemplary embodiments of the present invention proposed elevation forks and an aviation food cart having the same are described and/or illustrated in detail above. Embodiments of the invention are not limited to the specific embodiments described herein, but rather, components and/or steps of each embodiment may be utilized independently and separately from other components and/or steps described herein. Each component and/or step of one embodiment can also be used in combination with other components and/or steps of other embodiments. When introducing elements/components/etc. described and/or illustrated herein, the articles "a," "an," and "the" are intended to mean that there are one or more of the elements/components/etc. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements/components/etc. other than the listed elements/components/etc. Furthermore, the terms "first" and "second" and the like in the claims and the description are used merely as labels, and are not numerical limitations of their objects.
While the present invention has been described in terms of various specific embodiments and applications, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.

Claims (8)

1. A lifting fork frame is arranged between a frame and a carriage of a truck, and comprises a fork frame assembly, a hydraulic system for driving the fork frame assembly to lift and a controller for controlling the hydraulic system; the hydraulic system is characterized in that a proportional reversing valve is arranged on a system trunk of the hydraulic system, and the controller is connected to the proportional reversing valve and used for controlling the current value of the current input into a proportional electromagnet of the proportional reversing valve; the controller provides currents with corresponding current values to the proportional electromagnets according to a plurality of height intervals in the lifting fork frame stroke, so that the hydraulic flow supplied to the hydraulic system is controlled, and the lifting fork frame lifting speed of the carriage is controlled; the plurality of height intervals in the stroke of the lifting fork frame at least comprise a high interval, a stable interval and a low interval from high to low; when the lifting fork is positioned in the high-position interval, the stable interval and the low-position interval, the current values of the current given to the proportional electromagnet by the controller are respectively a first current value, a second current value and a third current value, and the third current value is larger than the first current value and smaller than the second current value; a rotating angle encoder is arranged on a rotating shaft of the lifting fork frame and used for detecting the rotating angle of the fork frame of the lifting fork frame; wherein the controller is connected to the rotation angle encoder to calculate the height interval of the lifting fork according to the angle.
2. The lifting fork as claimed in claim 1, wherein said lifting fork comprises a dual stage lifting hydraulic cylinder, and wherein said plurality of said elevation intervals in the lifting fork stroke further comprises a step change interval when a primary cylinder is shifted from a secondary cylinder; when the lifting fork is located in the gear shifting interval, the current value of the current given to the proportional electromagnet by the controller is the first current value.
3. The elevating fork as set forth in claim 2, wherein the staging interval is between the high interval and the plateau interval; or the stage change interval is between the steady interval and the low-order interval; or the stage changing interval is contained in the stable interval, the stable interval comprises a first stable interval and a second stable interval, and the height of the stage changing interval is smaller than the first stable interval and larger than the second stable interval.
4. The elevating fork as set forth in claim 1, wherein the elevating fork is raised and stationary at a height, and the elevating fork is automatically lowered, the controller controls the hydraulic system to drive the elevating fork to be raised back to the original height, and the controller supplies the proportional electromagnet with the first current value during the raising back.
5. The elevating fork of claim 1, wherein the controller is a PLC controller.
6. An aviation food cart comprises a frame and a carriage; it is characterized in that the aviation food vehicle further comprises:
the lift fork as claimed in any one of claims 1 to 5, which is provided between the frame and the car.
7. The aircraft food cart of claim 6, further comprising a four-way platform, wherein the four-way platform is disposed at an end of the carriage near a door of the aircraft, and a detection switch is disposed on the four-way platform; the controller is connected to the detection switch, a rotary encoder is used for detecting a fork angle of the lifting fork when the lifting fork ascends and descends, the height position of the carriage is obtained through calculation by the controller, the detection switch is triggered when the carriage ascends and is abutted to an airplane and the airplane descends to the height of the detection switch relative to the carriage, the controller controls the lifting fork to descend, and the current value of the current given to the proportional electromagnet by the controller is the first current value.
8. The aircraft food cart of claim 6 wherein said lift fork comprises a dual stage lift cylinder, said plurality of said elevation intervals in said lift fork travel further comprising a staging interval when a primary cylinder is staged with a secondary cylinder; when the lifting fork is positioned in the gear shifting interval, the current value of the current given to the proportional electromagnet by the controller is the first current value; wherein the staging interval is between the high interval and the plateau interval; or the stage change interval is between the steady interval and the low-order interval; or the stage changing interval is contained in the stable interval, the stable interval comprises a first stable interval and a second stable interval, and the height of the stage changing interval is smaller than the first stable interval and larger than the second stable interval; the plurality of height intervals in the stroke of the lifting fork frame comprise a high interval, a first stable interval, a grading interval, a second stable interval and a low interval, when the current values of the current given to the proportional electromagnet by the controller are respectively a first current value, a second current value and a third current value, the high interval is 6.8-8.1 m, the first stable interval is 5.5-6.8 m, the grading interval is 5.3-5.5 m, the second stable interval is 3.4-5.3 m, and the low interval is below 3.4 m; and/or the presence of a gas in the gas,
the first current value is 0.2A-0.4A, the second current value is 0.9A-1A, and the third current value is 0.5A-0.6A.
CN201711433518.4A 2017-12-26 2017-12-26 Lifting fork frame and aviation food vehicle with same Active CN108569640B (en)

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CN111114818B (en) * 2020-02-12 2021-11-09 民航协发机场设备有限公司 Height adjusting device and aviation food vehicle with same
CN112032125A (en) * 2020-05-14 2020-12-04 廊坊中集空港设备有限公司 Hydraulic system and aviation food car
CN114294273B (en) * 2021-12-31 2022-10-14 江苏徐工工程机械研究院有限公司 Hydraulic control system, tractor and hydraulic control method

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CN101437742A (en) * 2006-05-09 2009-05-20 东芝电梯株式会社 Terminal landing speed control system of elevator
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Effective date of registration: 20210621

Address after: 102206 b4061, building 8, No. 97, Changping Road, Shahe Town, Changping District, Beijing (Changping Demonstration Park)

Patentee after: XINFA AIRPORT EQUIPMENT Ltd.

Patentee after: LANGFANG CIMC AIRPORT EQUIPMENT Co.,Ltd.

Address before: 518067 CIMC R & D center, No. 2 Harbour Road, Shekou Industrial Zone, Guangdong, Shenzhen

Patentee before: China International Marine Containers (Group) Co.,Ltd.

Patentee before: XINFA AIRPORT EQUIPMENT Ltd.

Patentee before: CIMC TIANDA HOLDING (SHENZHEN) Ltd.