Automatic lifting device

Abstract

The invention relates to an automatic lifting device, and belongs to the technical field of automatic manufacturing. The device has triple safety insurance measures and has high-reliability bearing capacity. The method comprises the following steps: (1) an electric cylinder and a servo motor provide supporting force in the vertical direction in a static state; (2) the pneumatic balancing device provides reverse tension; and (3) the mechanical bolt extends out of a specified position to form rigid connection with the main frame. The device is used for moving and positioning a bearing workpiece in the vertical direction, and is matched with one or more industrial robots to form an equipment unit, so that the bearing workpiece can be subjected to automatic process treatment, and the height change of a target positioning point at the tail end of the industrial robot in the vertical direction is reduced; and the positioning precision of the industrial robot in high-frequency repeated motion is ensured.

Description

Technical Field

[0001] This invention belongs to the field of automated manufacturing technology and relates to an automatic lifting device. Background Technology

[0002] With the development of automation technology, industrial robots are being used more and more widely in the field of composite material molding. When industrial robots are processing workpieces, they usually need to move the workpieces due to travel limitations and cycle time arrangements, and require high-precision positioning.

[0003] According to existing mature technologies, automated manufacturing equipment is generally arranged in a production line within the factory floor plan. Workpieces move along the production line to preset stop positions. After the workpiece comes to rest and is precisely positioned, one or more industrial robots simultaneously perform processing on the workpiece. After the industrial robots complete their processing, they return to zero and stop, and then the workpiece moves to the next stop position. In most cases, the workpiece mainly moves horizontally. Due to factors such as space height and load weight affecting equipment accuracy and safety, vertical movement is less common, and process devices for vertical workpiece movement are also relatively rare.

[0004] The positioning accuracy of commercially available industrial robots is typically affected by arm span and load factors. Within the reach of the end effector, the arm span and load center of gravity vary significantly depending on the robot's working posture. According to the load curve, positioning accuracy drops sharply, especially within certain ranges. Relying solely on the robot's arm span to complete machining operations over a large spatial area will result in significant positioning deviations. Therefore, to improve the positioning accuracy of industrial robots in workpiece machining, it is necessary to minimize the robot's arm span range of motion, especially reducing vertical height differences. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide an automatic lifting device for carrying workpieces to move and position in the vertical direction. It can be used in conjunction with one or more industrial robots to form a device unit, which can perform automated processing on workpieces, reduce the height change of the target positioning point of the industrial robot end in the vertical direction, and ensure the positioning accuracy of the industrial robot in high-frequency repetitive motion.

[0006] The technical solution of this invention is: an automatic lifting device comprising a steel structure frame, an electric cylinder, a servo motor, a square box, a truss structure, a bearing platform, a sliding shoe, and fixed feet; wherein:

[0007] The steel frame structure is installed in the concrete foundation and is fixedly connected to the foundation plane by fixed anchors. The upper surface of the foundation is slightly lower than the factory floor. When in use, it is filled with steel protective plates to ensure the safety of personnel walking.

[0008] The moving parts include a square box, a truss structure, a load-bearing platform, and sliding shoes. The square box, truss structure, and load-bearing platform are welded and fixed together from bottom to top. Four sliding shoes are vertically installed on the four corners of the square box, which contact the four columns of the steel structure frame to form a sliding pair. The square box and truss structure have a circular hole in the center. The electric cylinder passes vertically through the circular hole but does not contact the square box or truss structure.

[0009] The power components include a servo motor, a reducer, and an electric cylinder. The electric cylinder can be driven by the servo motor to extend or retract with high precision. The electric cylinder mainly consists of a housing and a spindle. The housing has internal threads, and the spindle is a lead screw; together, they form a lead screw and nut pair. The housing end of the electric cylinder is fixed to a concrete foundation. The spindle end is connected to the output end of the servo motor via the reducer and is fixed to the lower surface of the support platform along with the servo motor. The servo motor provides the power source, driving the spindle to rotate. The lead screw and nut pair converts the rotational motion into linear motion, driving the moving parts to move up and down.

[0010] Preferably, the above-mentioned automatic lifting device further includes four pneumatic balancing devices, with two pneumatic balancing devices forming a group. The two groups of pneumatic balancing devices are symmetrically distributed on both sides of the steel structure frame, and are used to pull the bearing platform from the top of the steel structure frame, provide reverse tension to the bearing platform, and prevent the bearing platform from falling uncontrollably downwards.

[0011] Preferably, the pneumatic balancing device includes a reversing pulley block, a wire rope, and a balancing cylinder; wherein:

[0012] The cylinder body of the balancing cylinder is vertically mounted on the side of the steel structure frame, and the reversing pulley group is mounted on the top of the main frame. The cylinder rod extending from the balancing cylinder is connected to the square box by a steel wire rope, and the steel wire rope is reversed in direction by the reversing pulley group.

[0013] Preferably, the balancing cylinder is always in an inflated state, and the internal pressure of the cylinder is controlled by a venting valve. When the platform is rising, the venting valve is closed, the cylinder volume increases, the internal pressure decreases, and no power is provided. When the platform is descending, the venting valve is opened, the cylinder volume decreases, the internal pressure increases, and the pressure is reduced by the venting valve to achieve balance. If the downward speed of the lifting platform exceeds the safe range, the cylinder volume decreases rapidly, and the cylinder pressure suddenly increases, causing the venting valve to be unable to release air quickly, thereby providing passive pulling force and preventing the lifting platform from going out of control.

[0014] Preferably, the steel structure frame is a steel structure, welded and formed, and the residual welding stress is eliminated by heat treatment.

[0015] Preferably, the above-mentioned automatic lifting device also includes a grating ruler. The scale of the grating ruler is installed on the column of the steel structure frame, covering the entire effective stroke of the power walking mechanism. The measuring head of the grating ruler is connected to the square box and moves together with the power walking mechanism.

[0016] Preferably, the above-mentioned automatic lifting device further includes a measurement feedback system, which collects data measured by a grating ruler and feeds it back to the servo motor. The data fed back by the grating ruler is height data, which can be converted into the rotation angle of the spindle based on the pitch parameter of the lead screw and nut pair of the electric cylinder. This angle is then multiplied by the speed ratio parameter of the servo motor reducer. After conversion, the number of rotations of the servo motor is obtained, thus forming a closed loop for the precision control of the lifting device and achieving a positioning resolution of 0.01mm.

[0017] Preferably, the measurement resolution of the grating ruler is higher than 0.01 mm.

[0018] Preferably, the square box is equipped with four pin cylinders, and the columns of the steel structure frame have positioning holes at corresponding positions of the fixed stop position. The pin cylinders and positioning holes cooperate to form a safety locking mechanism. When the square box moves to the designated position, the pin of the pin cylinder extends and enters the positioning hole on the column to form a rigid connection. At this time, the square box is not allowed to move. When the square box stops at other positions, the safety locking mechanism is not effective.

[0019] Preferably, the servo motor is equipped with a braking mechanism, which releases the brake when powered on and automatically locks the brake when powered off.

[0020] The advantages of this invention compared to the prior art are:

[0021] (1) The present invention adopts a design scheme of servo motor and electric cylinder, which forms a closed loop with the measurement feedback system and works together to ensure the accuracy of use; the servo motor and electric cylinder are lifted from the center of the lifting platform, and the four slippers are installed on the four columns of the steel structure, which is conducive to the uniform force on the bearing platform and prevents overturning.

[0022] (2) The present invention uses a pneumatic balancing device to provide a reverse pulling force to balance the load weight and increase the load-bearing capacity in a static state; with the servo motor power and electric cylinder load-bearing capacity fixed, the reverse pulling force of the pneumatic balancing device is superimposed to effectively improve the maximum load-bearing capacity of the lifting device.

[0023] (3) The electric cylinder brake is unlocked after the servo motor is powered on, and the pin cylinder provides a hard limit. This invention adopts a combination of electric cylinder brake and pin cylinder to prevent falls and improve equipment reliability. Attached Figure Description

[0024] Figure 1 This is an automatic lifting device according to an embodiment of the present invention. Detailed Implementation

[0025] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, and the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0026] like Figure 1 As shown, this invention provides an automatic lifting device suitable for working conditions requiring high positioning accuracy and high safety and reliability. As a component of automated composite material molding equipment, it is mainly used for positioning workpieces at any specified position within their effective vertical stroke. The automatic lifting device includes a steel frame 2, an electric cylinder 8, a servo motor, a square box 6, a sliding shoe, a supporting platform 3, and fixed feet 7.

[0027] 1. Power-driven walking mechanism

[0028] The supporting platform 3, the square box 6, the electric cylinder 8, and the sliding shoe 10 constitute the power walking mechanism. The bottom of the servo motor housing is directly connected to the foundation, improving the stability of the power walking mechanism.

[0029] The steel frame 2 is installed in the concrete foundation and is fixedly connected to the foundation plane by the fixed footing 7. The upper surface of the foundation is slightly lower than the factory floor. When in use, it is filled with steel protective plates to ensure the safety of personnel walking.

[0030] The moving parts include a square box 6, a truss structure 11, a load-bearing platform 3, and sliding shoes; the square box 6, the truss structure 11, and the load-bearing platform 3 are welded and fixed together from bottom to top. Four sliding shoes are vertically installed on the four corners of the square box, which contact the four columns of the steel structure frame 2 to form a sliding pair; the square box 6 and the truss structure 11 have a circular hole in the center, and the electric cylinder 8 passes vertically through the circular hole but does not contact the square box 6 and the truss structure 11.

[0031] The power components include a servo motor, a reducer, and an electric cylinder (8). The electric cylinder can be driven by the servo motor to extend or retract with high precision. The electric cylinder mainly consists of a housing and a spindle. The housing has internal threads, and the spindle is a lead screw; the two form a lead screw and nut pair. The housing end of the electric cylinder is fixed to a concrete foundation. The spindle end is connected to the output end of the servo motor via the reducer and is fixed together with the servo motor to the lower surface of the support platform. The servo motor provides the power source, driving the spindle to rotate. When the spindle rotates, the lead screw and nut pair converts the rotational motion into linear motion, driving the moving parts to move up and down.

[0032] The servo motor is equipped with a braking mechanism. The brake is released when the power is on and automatically locks when the power is off, ensuring the safety of the entire mechanism from the power source.

[0033] The steel frame is a welded steel structure, with residual welding stress eliminated through heat treatment. The steel frame is fixed to the concrete foundation using anchor bolts. Four columns act as guide rails, providing support for the powered walking mechanism.

[0034] The sliding shoe is made of brass and makes direct contact with the four columns of the steel structure frame to ensure the straightness of the load-bearing platform 3 as it moves up and down.

[0035] 2. Pneumatic balancing device

[0036] The aforementioned automatic lifting device also includes four pneumatic balancing devices, with each pair of pneumatic balancing devices forming a group. The two groups of pneumatic balancing devices are symmetrically distributed on both sides of the steel structure frame 2. They are used to pull the bearing platform 3 from the top of the steel structure frame 2, providing a reverse pulling force to the bearing platform 3 and preventing the bearing platform 3 from falling uncontrollably.

[0037] The pneumatic balancing device includes a reversing pulley block 1, a steel wire rope, and a balancing cylinder 5; wherein:

[0038] The cylinder body of the balancing cylinder is vertically mounted on the side of the steel structure frame, with the cylinder rod extending upwards to provide safe balance when the entire device is stationary. The reversing pulley block 1 is installed on the top of the main frame. One end of the wire rope is connected to the cylinder rod pull ring, and the other end is reversed via a fixed pulley at the top of the steel structure frame before connecting to the square box. The extended cylinder rod of the balancing cylinder is connected to the square box via a wire rope, which is redirected through the reversing pulley block 1.

[0039] The cylinder's intake valve is connected to a compressed air source within the factory and remains open to supply compressed air. The cylinder pressure is controlled by the opening and closing of the vent valve.

[0040] When the power-driven walking mechanism moves upward, the cylinder vent valve closes, while the intake valve remains open. The slider inside the cylinder moves downward, reducing the internal pressure and preventing pressure from being supplied externally.

[0041] When the power-driven walking mechanism moves downwards, the cylinder vent valve opens, while the intake valve remains open. The slider inside the cylinder moves upwards within the cylinder body. Under the downward traction of the power-driven walking mechanism and the force of gravity, the internal space of the cylinder decreases, increasing the internal pressure. The cylinder then provides a reverse traction force to prevent the power-driven walking mechanism from going out of control.

[0042] The balancing cylinder is always in a charged state, and the internal pressure of the cylinder is controlled by the venting valve. When the supporting platform 3 rises, the venting valve is closed, the cylinder volume increases, the internal pressure decreases, and no power is provided. When the supporting platform 3 descends, the venting valve is opened, the cylinder volume decreases, the internal pressure increases, and the pressure is reduced by the venting valve to achieve balance. If the downward speed of the lifting platform exceeds the safe range, the cylinder volume decreases rapidly, and the cylinder pressure suddenly increases, causing the venting valve to be unable to release air quickly, thereby providing passive pulling force to prevent the lifting platform from going out of control.

[0043] 3. Feedback Measurement System

[0044] Preferably, the measuring system mainly consists of a grating ruler. The aforementioned automatic lifting device also includes a grating ruler 9 and a measurement feedback system. The scale of the grating ruler is installed on the columns of the steel structure frame, covering the entire effective stroke of the power walking mechanism. The measuring head of the grating ruler is connected to the square box and moves together with the power walking mechanism. Measurement data is generated on the grating ruler.

[0045] The measurement feedback system collects the height data of the bearing platform 3 obtained by the grating ruler. Based on the pitch parameter of the lead screw and nut pair of the electric cylinder, the height data of the bearing platform 3 is converted into the rotation angle of the spindle. Then, it is multiplied by the speed ratio parameter of the servo motor reducer to obtain the number of rotations of the servo motor. The lifting device is then controlled to form a closed loop.

[0046] The measurement resolution of the grating ruler is higher than 0.01 mm.

[0047] 4. Safety locking mechanism

[0048] The square box is equipped with four pin cylinders. The columns of the steel structure frame have positioning holes at the corresponding positions of the fixed stop position. The pin cylinders and positioning holes cooperate to form a safety locking mechanism. When the square box moves to the designated position, the pin of the pin cylinder extends and enters the positioning hole on the column to form a rigid connection. At this time, the square box is not allowed to move. When the square box stops at other positions, the safety locking mechanism is not effective.

[0049] The positioning hole can be located at half the lifting stroke of the power walking mechanism or at the highest point. The pin cylinder 4 can extend the pin at the two stop positions of half the lifting stroke and the highest point to lock with the reserved opening in the steel structure frame 2.

[0050] The above-mentioned automatic lifting device is used as follows:

[0051] 1. During the lifting process, the electric cylinder and servo motor provide upward power, and the internal capacity of the cylinder is increasing, without providing reverse pulling force.

[0052] 2. When the box rises to the half-stop position or the highest stop position, the pin of the pin cylinder extends and forms a rigid connection with the hole on the main steel frame structure, which can prevent the bearing platform 3 from sliding down.

[0053] 3. During the descent of the lifting platform, the electric cylinder and servo motor provide downward power, and the internal capacity of the cylinder is decreasing. The reversing pulley group provides reverse tension to prevent the supporting platform 3 from falling uncontrollably. At the same time, the gas in the compressed cylinder is discharged uniformly to the outside through the pressure relief valve to prevent the gas pressure in the cylinder from rising.

[0054] In summary, the device has triple safety measures, providing both high-precision positioning capabilities and high safety and reliability.

[0055] (1) The design scheme of servo motor and electric cylinder is adopted to form a closed loop with the measurement feedback system to ensure the accuracy of use;

[0056] (2) A pneumatic balancing device is used to provide a reverse tension to balance the load weight and increase the load-bearing capacity in a static state;

[0057] (3) The mechanical measures of electric cylinder brake and pin cylinder are used to prevent falling and improve the reliability of the equipment.

[0058] According to the present invention, an automatic lifting process device with strong load-bearing capacity, high-precision closed-loop control, and multiple stop safety measures is specially designed for carrying workpieces to move and position in the vertical direction, and the total lifting stroke can reach 2 meters.

[0059] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features.

Claims

1. An automatic lifting device, characterized in that, Includes a steel frame (2), fixed foundation (7), moving parts, and power components; wherein: The steel structure frame (2) is installed in the concrete foundation and is fixedly connected to the foundation plane by the fixed foot (7). The upper surface of the steel structure frame is slightly lower than the factory floor. When in use, it is filled with steel protective plate to ensure the safety of personnel walking. The moving parts include a square box (6), a truss structure (11), a load-bearing platform (3), and sliding shoes; the square box (6), the truss structure (11), and the load-bearing platform (3) are welded and fixed together from bottom to top. Four sliding shoes are vertically installed on the four corners of the square box, which are in contact with the four columns of the steel frame (2) to form a sliding pair; the square box (6) and the truss structure (11) have a circular hole in the center, and the electric cylinder (8) passes vertically through the circular hole but does not contact the square box (6) and the truss structure (11); The power components include a servo motor, a reducer, and an electric cylinder (8); the housing end of the electric cylinder is fixed on the concrete foundation; the spindle end of the electric cylinder is connected to the output end of the servo motor through the reducer, and is fixed together with the servo motor on the lower surface of the bearing platform. The servo motor provides the power source and drives the spindle to rotate. The lead screw and nut pair converts the rotational motion into linear motion, which drives the moving parts to move up and down.

2. An automatic lifting device according to claim 1, characterized in that It also includes four pneumatic balancing devices, with two pneumatic balancing devices forming a group. The two groups of pneumatic balancing devices are symmetrically distributed on both sides of the steel structure frame (2) to pull the bearing platform (3) from the top of the steel structure frame (2) and provide a reverse pull force to the bearing platform (3) to prevent the bearing platform (3) from falling down uncontrollably.

3. An automatic lifting device according to claim 1, characterized in that, The pneumatic balancing device includes a reversing pulley block (1), a steel wire rope, and a balancing cylinder (5); wherein: The cylinder body of the balancing cylinder is vertically installed on the side of the steel structure frame, and the reversing pulley group (1) is installed on the top of the main frame. The cylinder rod extending from the balancing cylinder is connected to the square box by a steel wire rope, and the steel wire rope is reversed in direction by the reversing pulley group (1).

4. An automatic lifting device according to claim 3, characterized in that, The balancing cylinder is always in an inflated state, and the pressure inside the cylinder is controlled by the venting valve. When the balancing cylinder is on the support platform (3) rising, the venting valve is closed, the cylinder volume increases, the internal pressure decreases, and no power is provided. When the balancing cylinder is on the support platform (3) falling, the venting valve is opened, the cylinder volume decreases, the internal pressure increases, and the pressure is reduced by the venting valve to achieve balance. If the downward speed of the lifting platform exceeds the safe range, the cylinder volume decreases rapidly, and the cylinder pressure suddenly increases, causing the venting valve to be unable to release air quickly, thereby providing passive pulling force to prevent the lifting platform from going out of control.

5. An automatic lifting device according to claim 1, characterized in that, The steel frame is a steel structure, welded together and heat-treated to eliminate residual welding stress.

6. An automatic lifting device according to claim 1, characterized in that, It also includes a grating ruler (9), the scale of which is installed on the column of the steel structure frame, covering the entire effective stroke of the power walking mechanism. The measuring head of the grating ruler is connected to the square box and moves together with the power walking mechanism.

7. An automatic lifting device according to claim 1, characterized in that, It also includes a grating ruler and a measurement feedback system. The measurement feedback system collects the height data of the bearing platform (3) measured by the grating ruler. Based on the pitch parameter of the screw nut pair of the electric cylinder, the height data of the bearing platform (3) is converted into the rotation angle of the spindle. Then, it is multiplied by the speed ratio parameter of the servo motor reducer to obtain the number of rotations of the servo motor. The lifting device is controlled to form a closed loop.

8. An automatic lifting device according to claim 7, characterized in that, The measurement resolution of the grating ruler is higher than 0.01 mm.

9. An automatic lifting device according to claim 1, characterized in that, The square box is equipped with four pin cylinders. The columns of the steel structure frame have positioning holes at the corresponding positions of the fixed stop position. The pin cylinders and positioning holes cooperate to form a safety locking mechanism. When the square box moves to the designated position, the pin of the pin cylinder extends and enters the positioning hole on the column to form a rigid connection. At this time, the square box is not allowed to move. When the square box stops at other positions, the safety locking mechanism is not effective.

10. An automatic lifting device according to claim 1, characterized in that, The servo motor is equipped with a braking mechanism. The brake is released when the power is on and automatically locks when the power is off.

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