High-sensitivity resistance detection device and lifting stand column

Abstract

The invention provides a high-sensitivity resistance detection device, namely a lifting upright post, the device comprises a mounting seat, a conduction piece, a sensing element, a first elastic piece and a second elastic piece, and the first elastic piece and the second elastic piece are stacked up and down and are mounted on the mounting seat under the action of the conduction piece; the conduction piece penetrates through the first elastic piece and the second elastic piece from top to bottom and transmits loads to the first elastic piece and the second elastic piece. The sensing element is arranged on the first elastic sheet; the lifting stand column comprises a sleeve, a transmission assembly and the device, the transmission assembly is arranged in the sleeve and drives the sleeve to stretch out and draw back, the device is installed on the sleeve, a conduction piece is connected with an end plate of the sleeve, and an installation plate is connected with the transmission assembly from an opening of the end plate; a single elastic piece is replaced by double elastic pieces, the two elastic pieces have different functions, the first elastic piece is used for outputting deformation quantity to the sensing element, the second elastic piece is used for bearing a load, and the first elastic piece and the second elastic piece are clear in work division and perform their own functions, so that resistance backspacing detection is more accurate, sensitive and stable.

Description

Technical Field

[0001] The invention relates to the field of furniture, and in particular to a high-sensitivity resistance detection device and a lifting column. Background Art

[0002] Electric furniture, such as electric beds and electric tables, has functions such as automatic lifting and automatic flipping, which is convenient for users. In order to prevent electric furniture from pinching users during activities, an obstacle retreat function is usually set on electric furniture. That is, when an obstacle is sensed during movement, the device will immediately move in the opposite direction to avoid the obstacle, thereby preventing damage to the furniture or pinching the user.

[0003] There is currently an resistance detection device for a single-motor lifting table, which mainly includes a single spring piece and a sensing element. The sensing element is a piezoelectric piece. The load of the lifting table can be transferred to the spring piece. When the load on the lifting table changes, the spring piece deforms. The sensing element outputs a signal for judging the resistance situation according to the deformation amount of the spring piece. When the signal value of the signal exceeds a preset threshold or the difference with the previous signal value is greater than the preset threshold, it is judged that resistance occurs, and the lifting table stops and moves in the opposite direction.

[0004] In the solution of a single shrapnel, the shrapnel is used to bear the load and needs to deform as the basis for resistance detection. Therefore, the signals generated during normal operation and the signals generated when encountering resistance are relatively flat, and the difference between the peak values ​​is small, resulting in poor sensitivity of resistance detection. In addition, the single-motor lifting table has many interferences during operation, such as motor vibration, transmission rod disturbance due to insufficient straightness, etc., which increases the noise points, resulting in the resistance signal not being prominent enough, that is, the useful signal is difficult to be accurately collected, which further leads to a decrease in the sensitivity of resistance detection. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a high-sensitivity resistance detection device, including a mounting seat, a conductive member, a sensing element and a plurality of spring pieces, the plurality of spring pieces including a bearing spring piece and at least one signal spring piece, the plurality of spring pieces are stacked up and down and mounted on the mounting seat under the action of the conductive member, the conductive member passes through all the spring pieces from top to bottom and transfers the load to all the spring pieces; the sensing element is arranged on the signal spring piece, and a single spring piece is replaced by a plurality of spring pieces, at least two spring pieces, and their functions are different, the signal spring piece is used to output a deformation amount to the sensing element, and the bearing spring piece is used to bear the load, the signal spring piece and the bearing spring piece have clear division of labor and perform their respective functions, the bearing spring piece bears most of the load for the signal spring piece, but does not affect the deformation of the signal spring piece, that is, after the bearing spring piece bears the main load, the signal spring piece is reduced The influence of the load size and its change is reduced, thereby making the signal spring piece have a more accurate, stable and sensitive deformation output, and the sensing element generates a signal according to the deformation amount of the signal spring piece, so that the resistance retreat detection is more accurate, sensitive and stable.

[0006] A lifting column is further provided, comprising a sleeve, a transmission assembly and the above-mentioned resistance detection device, wherein the transmission assembly is arranged in the sleeve and drives the sleeve to extend and retract, the resistance detection device is installed on the sleeve and the conductive member is connected to the end plate of the sleeve, and the mounting plate is connected to the transmission assembly through the opening of the end plate.

[0007] The technical solution of the present invention is achieved in this way:

[0008] A highly sensitive resistance detection device comprises a mounting seat, a conductive member, a sensing element and a plurality of spring sheets, wherein the mounting seat is configured to be connected to a transmission assembly of a lifting column, the plurality of spring sheets are stacked up and down on the mounting seat, the conductive member is configured to pass through all the spring sheets and be connected to a sleeve of the lifting column and transfer a load to the spring sheets; the plurality of spring sheets comprise a signal spring sheet located at the outermost side and at least one load-bearing spring sheet located between the signal spring sheet and the mounting seat, the sensing element is arranged on the signal spring sheet, the load-bearing spring sheet is configured to bear a load, the signal spring sheet is configured to be deformed when the load of the load-bearing spring sheet changes, and the sensing element is configured to output a signal for judging a resistance situation according to the deformation amount of the signal spring sheet; when the load changes, the load transmitted by the conductive member to all the spring sheets changes, the spring sheets all deform, the sensing element detects the deformation amount of the signal spring sheet and outputs a signal for judging a resistance situation.

[0009] A single spring sheet is replaced by multiple spring sheets, and there are at least two spring sheets with different functions. The signal spring sheet is used to output the deformation amount to the sensing element, and the load-bearing spring sheet is used to bear the load. The signal spring sheet and the load-bearing spring sheet have clear division of labor and perform their respective functions. The load-bearing spring sheet bears most of the load for the signal spring sheet, but does not affect the deformation of the signal spring sheet. That is, after the load-bearing spring sheet bears the main load, the influence of the load size and its changes on the signal spring sheet is reduced, thereby making the signal spring sheet have a more accurate, stable and sensitive deformation amount output, and the sensing element generates a signal according to the deformation amount of the signal spring sheet, so that the resistance retreat detection is more accurate, sensitive and stable.

[0010] Preferably, the thickness of the signal shrapnel is smaller than that of the load-bearing shrapnel. A thinner signal shrapnel is more conducive to deformation and has a stronger deformation capacity, thereby making the signal output by the sensing element more sensitive and accurate; a thicker load-bearing shrapnel can bear most of the load more stably, minimizing the impact of excessive load or load change on the deformation capacity of the signal shrapnel.

[0011] A lifting column comprises a telescopic sleeve, a transmission assembly for driving the sleeve to be telescopic, and the above-mentioned resistance detection device, wherein the transmission assembly is arranged in the sleeve, the sleeve has an end plate located at its upper end, the end plate is provided with an opening, and the transmission assembly is exposed from the opening; the resistance detection device is installed on the sleeve, and the conductive member is connected to the end plate, and the mounting plate is connected to the transmission assembly from the opening.

[0012] In this solution, the transmission component is connected to the mounting seat, and the conductive member is connected to the end plate. When encountering resistance, a small relative movement occurs between the transmission component and the end plate, thereby causing the mounting seat and the conductive member to float relative to each other. Since the signal shrapnel and the bearing shrapnel are installed on the mounting seat under the action of the conductive member, when the mounting seat and the transmission member float relative to each other, the signal shrapnel and the bearing shrapnel are deformed, so that the sensing element can detect the deformation of the signal shrapnel, thereby realizing resistance detection.

[0013] Preferably, a recessed receiving groove is provided on the mounting seat, the bearing shrapnel is arranged in the receiving groove, and the signal shrapnel rests on the upper surface of the bearing shrapnel; a recessed deformation groove is provided on the bottom surface of the receiving groove, and the deformation groove is configured so that when the bearing shrapnel is deformed downward, the deformation groove avoids the bearing shrapnel. The existence of the receiving groove can reduce the overall thickness of the obstruction detection device, and can also facilitate the positioning and installation of the bearing shrapnel, so that the bearing shrapnel can be stably arranged on the mounting seat; both the signal shrapnel and the bearing shrapnel are annular, and an opening is provided in the center thereof, and the conductive member passes through the opening from top to bottom. When the bearing shrapnel is deformed downward, the portion of the bearing shrapnel close to the opening is deformed downward, and the deformation groove can avoid the bearing shrapnel.

[0014] Preferably, the bottom surface of the deformation groove is provided with an avoidance hole that passes through the mounting seat, and an elastic member is provided in the avoidance hole. The conductive member is inserted in the elastic member, and the upper end of the elastic member abuts against the load-bearing shrapnel, and the lower end of the elastic member abuts against the end plate. Giving the mounting seat and the end plate the ability to float relative to each other is equivalent to giving the mounting seat and the conductive member the ability to float relative to each other; when encountering resistance, a small relative movement occurs between the transmission component and the end plate of the sleeve. Since the mounting seat is connected to the transmission component, the mounting seat and the end plate can also float relative to each other under the action of the elastic member. Since the conductive member is connected to the end plate, the mounting seat and the conductive member also float relative to each other. Under the action of the conductive member and the mounting seat, the signal shrapnel and the load-bearing shrapnel are further deformed. The elastic member is a silicone or rubber cushion.

[0015] Preferably, the mounting seat includes a mounting plate and a convex portion protruding downward from the mounting plate, the convex portion abutting downward from the opening on the transmission assembly; and in the up and down directions, there are gaps between the transmission assembly and the end plate, and between the mounting plate and the end plate. The gap between the transmission assembly and the end plate, and the gap between the mounting plate and the end plate enable the transmission assembly and the end plate to float up and down, and the mounting plate can also float up and down relative to the end with the transmission assembly, so that the mounting plate is equivalent to the conductive member connected to the end plate floating up and down, causing the deformation of the signal spring sheet and the load-bearing spring sheet.

[0016] Preferably, the signal spring sheet and the load-bearing spring sheet have an initial deformation amount under the pressure of the conductive member. During installation, the conductive member passes through the signal spring sheet and the load-bearing spring sheet from top to bottom and applies a pre-tightening force to the signal spring sheet and the load-bearing spring sheet. The signal spring sheet and the load-bearing spring sheet have an initial deformation amount on the mounting seat. With the initial deformation amount, the signal spring sheet and the load-bearing spring sheet can have both an upward relative deformation and a downward relative deformation when encountering resistance, thereby achieving a two-way resistance detection effect.

[0017] Preferably, the conductive member is a bolt having a head at its upper end and a threaded portion having a diameter smaller than the head. The conductive member passes through the signal shrapnel and the load-bearing shrapnel from top to bottom and the head applies a pre-tightening force to the signal shrapnel and the load-bearing shrapnel. The threaded portion is threadedly connected to the end plate.

[0018] Preferably, the transmission assembly includes a gear box at the upper end, a connecting hole is provided on the mounting seat, and the lower end of the mounting seat abuts against the gear box and is connected to the gear box by setting a bolt in the connecting hole.

[0019] Preferably, the sensing element is a piezoelectric sheet. Using a piezoelectric sheet as a sensing element can effectively detect the deformation of the signal spring sheet, is easy to implement and has low cost.

[0020] The design starting point, concept and beneficial effects of the present invention using the above technical solution are:

[0021] The traditional single-shrapnel method is improved to a double-shrapnel method, which greatly improves the performance of resistance detection: the conductive part applies a pre-tightening force to the signal shrapnel and the load-bearing shrapnel. When it is lifted from rest to normal, the force (load) transmitted by the conductive part to the signal shrapnel and the load-bearing shrapnel changes, and the signal shrapnel and the load-bearing shrapnel are deformed. Among them, the load-bearing shrapnel bears the main role of bearing the load, and the signal shrapnel bears the role of giving the sensing element the deformation amount. The sensing element converts the detected deformation amount into a signal value and transmits it to the control unit. If the signal value is less than the trigger threshold of retreating when encountering resistance, the lifting table continues to work; when it is lifted from normal to encountering resistance, the conductive part The force (load) transmitted to the signal spring sheet and the load-bearing spring sheet by the component is further changed. The load-bearing spring sheet still bears the main load, reducing the influence of the load size and its changes on the signal spring sheet, thereby having a more accurate, stable and sensitive deformation output. Therefore, the sensing element generates a signal value according to the deformation of the signal spring sheet and transmits it to the control unit. At this time, the signal value is greater than the trigger threshold, and the control unit controls the lifting table to retreat when encountering resistance. Due to the design of double spring sheets, the deformation and signal values ​​are more accurate, stable and sensitive. Compared with the existing technology, the signal value when encountering resistance can obviously exceed the trigger threshold, making the retreat when encountering resistance more accurate, sensitive and stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the three-dimensional structure of the lifting column in an embodiment of the present invention;

[0023] Figure 2 is a cross-sectional view of the lifting column in an embodiment of the present invention;

[0024] Figure 3 It is a schematic diagram of the three-dimensional structure of the transmission assembly, the end plate and the resistance detection device in the embodiment of the present invention;

[0025] Figure 4 It is a schematic diagram of the three-dimensional structure of the gear box, the end plate and the resistance detection device in the embodiment of the present invention;

[0026] Figure 5 It is a side view of the gear box, the end plate and the resistance detection device in the embodiment of the present invention;

[0027] Figure 6 It is a schematic diagram of the three-dimensional structure of the conductive member and the end plate in an embodiment of the present invention;

[0028] Figure 7 It is a schematic diagram of the three-dimensional structure of the mounting seat abutting against the gear box in the embodiment of the present invention;

[0029] Figure 8 It is a waveform diagram of a single spring in the first group of experiments in the embodiment of the present invention;

[0030] Fig. 9It is a waveform diagram of the double springs in the first group of experiments in the embodiment of the present invention;

[0031] Fig.10 It is a waveform diagram of a single spring in the second group of experiments in the embodiment of the present invention;

[0032] Fig.11 It is a waveform diagram of the double springs in the second group of experiments in the embodiment of the present invention;

[0033] Fig.12 It is a waveform diagram of a single spring in the third group of experiments in the embodiment of the present invention;

[0034] Fig.13 It is a waveform diagram of the double springs in the third group of experiments in the embodiment of the present invention;

[0035] Fig.14 It is a waveform diagram of a single spring in the fourth group of experiments in the embodiment of the present invention;

[0036] Fig.15 It is a waveform diagram of the double springs in the fourth group of experiments in the embodiments of the present invention.

[0037] The reference numerals of the figures are: mounting seat 1; mounting plate 101; protrusion 102; conductive member 2; head 201; threaded portion 202; sensing element 3; signal spring 4; bearing spring 5; sleeve 6; transmission assembly 7; gear box 71; end plate 8; opening 9; accommodating groove 10; deformation groove 11; connecting hole 12; gap 13; avoidance hole 14; elastic member 15. DETAILED DESCRIPTION

[0038] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0039] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0040] In the description of the present invention, the terms “first”, “second”, “third”, etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0041] The specific implementation methods of the present invention are as follows:

[0042] like Figure 1 , 3As shown, the present invention provides a high-sensitivity encounter resistance detection device, including a mounting seat 1, a conductive member 2, a sensing element 3 and a plurality of springs. In this embodiment, there are two springs, namely a signal spring 4 and a load-bearing spring 5. The mounting seat 1 is configured to be connected to a transmission assembly 7 of a lifting column. The signal spring 4 and the load-bearing spring 5 are both mounted on the mounting seat 1. The conductive member 2 is configured to be connected to a sleeve 6 of the lifting column and transfer loads to the signal spring 4 and the load-bearing spring 5. The signal spring 4 and the load-bearing spring 5 are stacked up and down on the mounting seat 1, and the conductive member 2 passes through the signal spring 4 from top to bottom. The induction element 3 is arranged on the signal shrapnel 4, the load-bearing shrapnel 5 is configured to bear the load, the signal shrapnel 4 is configured to deform when the load of the load-bearing shrapnel 5 changes, and the induction element 3 is configured to output a signal for judging the resistance situation according to the deformation amount of the signal shrapnel 4; when the load changes, the load transmitted by the conductive part 2 to the signal shrapnel 4 and the load-bearing shrapnel 5 changes, the signal shrapnel 4 and the load-bearing shrapnel 5 produce corresponding deformation amounts, and the induction element 3 detects the deformation amount of the signal shrapnel 4 and outputs a signal for judging the resistance situation.

[0043] A double spring sheet is used instead of a single spring sheet. The two spring sheets have different functions. The signal spring sheet 4 is used to output the deformation amount to the sensing element 3, and the load-bearing spring sheet 5 is used to bear the load. The signal spring sheet 4 and the load-bearing spring sheet 5 have clear division of labor and each performs its own function. The load-bearing spring sheet 5 bears most of the load for the signal spring sheet 4, but does not affect the deformation of the signal spring sheet 4. That is, after the load-bearing spring sheet 5 bears the main load, the influence of the load size and its changes on the signal spring sheet 4 is reduced, thereby making the signal spring sheet 4 have a more accurate, stable and sensitive deformation amount output, and the sensing element 3 generates a signal according to the deformation amount of the signal spring sheet 4, so that the detection of retreat in case of resistance is more accurate, sensitive and stable.

[0044] The resistance detection device is applied to a lifting column, such as Figure 1-3As shown, the lifting column includes a telescopic sleeve 6, a transmission assembly 7 for driving the sleeve 6 to be telescopic, and the above-mentioned resistance detection device, the transmission assembly 7 is arranged in the sleeve 6, the sleeve 6 has an end plate 8 located at its upper end, the end plate 8 is provided with an opening 9, and the transmission assembly 7 is exposed from the opening 9; the resistance detection device is installed on the sleeve 6, and the conductive member 2 is connected to the end plate 8, and the mounting plate 101 is connected to the transmission assembly 7 from the opening 9; in this scheme, the transmission assembly 7 is connected to the mounting seat 1, and the conductive member 2 is connected to the end plate 8. When resistance occurs, a small relative movement occurs between the transmission assembly 7 and the end plate 8, thereby driving the mounting seat 1 and the conductive member 2 to float relatively. Since the signal shrapnel 4 and the bearing shrapnel 5 are installed on the mounting seat 1 under the action of the conductive member 2, when the mounting seat 1 and the transmission member float relatively, the signal shrapnel 4 and the bearing shrapnel 5 are deformed, so that the sensing element 3 can detect the deformation of the signal shrapnel 4, thereby realizing resistance detection.

[0045] The sensing element 3 is a piezoelectric sheet, which is annular and pasted on the upper surface of the signal shrapnel 4. The annular sensing element 3 can also avoid the conductive member 2 in the middle. Using a piezoelectric sheet as the sensing element 3 can effectively detect the deformation of the signal shrapnel 4, which is easy to implement and low cost.

[0046] like Figure 3-6 As shown, the conductive member 2 is a bolt, which has a head 201 located at its upper end and a threaded portion 202 with a diameter smaller than the head 201. The conductive member 2 passes through the signal shrapnel 4 and the load-bearing shrapnel 5 from top to bottom. The head 201 can apply a pre-tightening force to the signal shrapnel 4 and the load-bearing shrapnel 5, and the threaded portion 202 can be threadedly connected to the end plate 8; the signal shrapnel 4 and the load-bearing shrapnel 5 are both annular sheets with an opening in the center. The conductive member 2 passes through the opening from top to bottom, so the main deformation position of the signal shrapnel 4 and the load-bearing shrapnel 5 is located near the center of the circle.

[0047] The mounting seat 1 includes a mounting plate 101 and a convex portion 102 protruding downward from the mounting plate 101. The mounting plate 101 is provided with a recessed receiving groove 10. The bearing spring 5 is arranged in the receiving groove 10. The lower surface of the bearing spring 5 abuts against the receiving groove 10. The signal spring 4 rests on the upper surface of the bearing spring 5. The sensing element 3 is attached to the upper surface of the signal spring 4. The head 201 of the conductive member 2 abuts against the signal spring 4. The bottom surface of the receiving groove 10 is also provided with a recessed deformation groove 11. The deformation groove 11 is located at the center of the accommodating groove 10. The deformation groove 11 is configured so that when the load-bearing spring piece 5 is deformed downward, the deformation groove 11 can avoid the load-bearing spring piece 5. More specifically, when the load-bearing spring piece 5 is deformed downward, the portion of the load-bearing spring piece 5 close to the opening is deformed downward, and the deformation groove 11 can avoid the load-bearing spring piece 5. The existence of the accommodating groove 10 can reduce the overall thickness of the obstruction detection device, and can also facilitate the positioning and installation of the load-bearing spring piece 5, so that the load-bearing spring piece 5 can be stably set on the mounting seat 1.

[0048] Furthermore, in order to realize the resistance detection, the deformation of the signal spring piece 4 and the bearing spring piece 5 must be realized first. If the deformation of the signal spring piece 4 and the bearing spring piece 5 is to be realized, the movement of the mounting seat 1 and the conductive member 2 must be realized first. Specifically, Figure 2-7As shown, the transmission assembly 7 includes a gear box 71 and a screw nut assembly at the upper end, a connecting hole 12 is opened in the middle position of the mounting seat 1, and the connecting hole 12 passes through the mounting plate 101 and the protrusion 102 in the vertical direction, the lower end of the mounting seat 1 abuts on the gear box 71 and is connected to the gear box 71 by arranging bolts in the connecting hole 12, so as to realize the synchronous movement of the mounting seat 1 and the transmission assembly 7; wherein the protrusion 102 abuts on the gear box 71 of the transmission assembly 7 downward from the opening 9; and in the vertical direction, there are gaps 13 between the gear box 71 and the end plate 8 of the transmission assembly 7, and between the mounting plate 101 and the end plate 8; and, the bottom surface of the deformation groove 11 is opened with an avoidance hole 14 passing through the mounting plate 101, and an elastic member 15 is arranged in the avoidance hole 14, the conductive member 2 is inserted in the elastic member 15, the upper end of the elastic member 15 abuts against the load-bearing spring sheet 5, and the elastic member 15 The lower end is in contact with the end plate 8; giving the mounting seat 1 and the end plate 8 the ability to float relative to each other is equivalent to giving the mounting seat 1 and the conductive member 2 the ability to float relative to each other; when encountering resistance, a small relative movement occurs between the transmission component 7 and the end plate 8 of the sleeve 6. Since the mounting seat 1 is connected to the transmission component 7, under the action of the elastic member 15, relative floating can also occur between the mounting seat 1 and the end plate 8. Since the conductive member 2 is connected to the end plate 8, the mounting seat 1 and the conductive member 2 also float relative to each other. Under the action of the conductive member 2 and the mounting seat 1, the signal shrapnel 4 and the bearing shrapnel 5 are further deformed; the elastic member 15 is in contact with the bearing shrapnel 5, and can also more intuitively give the deformation result of the bearing shrapnel 5 after the mounting seat 1 floats, and can also prevent the signal shrapnel 4 and the bearing shrapnel 5 from excessive deformation and creep, thereby weakening the effect of resistance detection; in addition, the elastic member 15 is a silicone or rubber cushion.

[0049] The gap 13 between the transmission component 7 and the end plate 8 and the gap 13 between the mounting plate 101 and the end plate 8 enable the transmission component 7 and the end plate 8 to float up and down, and the mounting plate 101 can also float up and down relative to the end with the transmission component 7, so that the mounting plate 101 is equivalent to the conductive part 2 connected to the end plate 8 floating up and down, causing deformation of the signal spring piece 4 and the load-bearing spring piece 5.

[0050] In order to realize bidirectional resistance detection, during installation, the head 201 of the conductive member 2 needs to give a pre-tightening force to the signal spring sheet 4 and the bearing spring sheet 5, that is, the signal spring sheet 4 and the bearing spring sheet 5 have an initial deformation amount under the pressure of the conductive member 2. During installation, the conductive member 2 passes through the signal spring sheet 4 and the bearing spring sheet 5 from top to bottom and applies a pre-tightening force to the signal spring sheet 4 and the bearing spring sheet 5. The signal spring sheet 4 and the bearing spring sheet 5 have an initial deformation amount on the mounting seat 1. With the initial deformation amount, the signal spring sheet 4 and the bearing spring sheet 5 can have both an upward relative deformation and a downward relative deformation when resistance occurs, thereby realizing the effect of bidirectional resistance detection.

[0051] In addition, in order to further enhance the effect of clear division of labor of the double shrapnel, the thickness of the signal shrapnel 4 is smaller than the thickness of the load-bearing shrapnel 5. When the thicker load-bearing shrapnel 5 is located below the signal shrapnel 4, the load-bearing shrapnel 5 can share most of the load for the signal shrapnel 4, allowing the signal shrapnel 4 to focus on deformation; the signal shrapnel 4 is thinner, more conducive to deformation, and has a stronger deformation ability, so that the signal output by the sensing element 3 is more sensitive and accurate; the load-bearing shrapnel 5 is thicker, and can bear most of the load more stably, minimizing the impact of excessive load or load changes on the deformation ability of the signal shrapnel 4.

[0052] Furthermore, the mounting base 1 has two mounting positions for springs, that is, the mounting base 1 is provided with two groups of signal springs 4, supporting springs 5 ​​and sensing elements 3, and the mounting base 1 is obliquely placed on the end plate 8, and the two groups of signal springs 4, supporting springs 5 ​​and sensing elements 3 are diagonally arranged at the end, so as to obtain a more accurate resistance detection signal.

[0053] The traditional single-shrapnel method is improved to a double-shrapnel method, which greatly improves the performance of resistance detection: the conductive member 2 applies a pre-tightening force to the signal shrapnel 4 and the load-bearing shrapnel 5. When it is lifted from rest to normal lifting, the force (load) transmitted by the conductive member 2 to the signal shrapnel 4 and the load-bearing shrapnel 5 changes, and the signal shrapnel 4 and the load-bearing shrapnel 5 are deformed, among which the load-bearing shrapnel 5 bears the main role of bearing the load, and the signal shrapnel 4 bears the role of giving the sensing element 3 a deformation amount. The sensing element 3 converts the detected deformation amount into a signal value and transmits it to the control unit. If the signal value is less than the trigger threshold for retreating when encountering resistance, the lifting table continues to work; when it is lifted from normal lifting to encountering resistance, , the force (load) transmitted by the conductive member 2 to the signal shrapnel 4 and the load-bearing shrapnel 5 is further changed, and the load-bearing shrapnel 5 still bears the main load, reducing the influence of the load size and its changes on the signal shrapnel 4, thereby having a more accurate, stable and sensitive deformation output. Therefore, the sensing element 3 generates a signal value according to the deformation of the signal shrapnel 4 and transmits it to the control unit. At this time, the signal value is greater than the trigger threshold, and the control unit controls the lifting table to retreat when encountering resistance; due to the design of double shrapnel, the deformation and signal value are more accurate, stable and sensitive. Compared with the prior art, the signal value when encountering resistance can significantly exceed the trigger threshold, making the retreat when encountering resistance more accurate, sensitive and stable.

[0054] The sensing element 3 transmits the signal value to the control unit at all times, so a wave is formed, such as Figure 8 , 9As shown, no matter when stationary, rising or falling normally or when encountering resistance, the wave formed in the single-shrapnel form will be smoother than the wave formed in the double-shrapnel form. Especially when encountering resistance, the difference between the wave crest produced by the single-shrapnel resistance device and that in normal conditions is smaller, which makes it difficult to break through the trigger threshold, and the sensitivity and accuracy of resistance detection are poor. The double-shrapnel resistance device has a larger wave crest, which solves this problem and makes resistance detection more sensitive and accurate.

[0055] In order to further illustrate the better effect of the double spring clip, a single spring clip and a double spring clip were used respectively on two identical lifting tables to carry out resistance experiments, and the experimental data were compared; in this experiment, a single spring clip with a thickness of 1.8mm was selected and the experimental data was transmitted by it, and a double spring clip with a thickness of 0.6mm+1.2mm was selected, and the experimental data was transmitted by the spring clip with a thickness of 0.6mm, and 4 groups of comparative experiments were carried out. In the first group of experiments, the lifting table was empty and ascended; in the second group of experiments, the lifting table descended with a load of 10kg, and the 10kg load was removed to restore the empty load, so as to simulate the situation where the lifting table encountered resistance when descending; in the third group of experiments, the lifting table had a load of 20kg and ascended; in the fourth group of experiments, the lifting table descended with a load of 30kg, and the 10kg load was removed to restore the load to 20kg, so as to simulate the situation where the lifting table encountered resistance when descending. After conducting the above four groups of experiments, the waveforms generated by the four groups of experiments were obtained, and the experimental data were obtained. In the waveforms, the horizontal coordinate represents time, in units of ms or s, and the vertical coordinate represents the piezoelectric signal value generated by the deformation of the spring, in units of mv; the waveform of the experiment is as follows Figure 8-15 The experimental data table is shown below:

[0056]

[0057]

[0058]

[0059] The first and third experiments are both experiments under normal rising conditions of the lifting table. For reference, the maximum value represents the maximum value of the piezoelectric signal waveform, and the minimum value represents the minimum value of the piezoelectric signal waveform; in the second and fourth experiments, the maximum value before removal represents the maximum value of the piezoelectric signal waveform under normal working conditions, and the maximum value during removal represents the maximum value of the piezoelectric signal waveform generated when resistance occurs. The larger the difference between the two, the more conducive it is to judging whether resistance occurs. From the second experiment, it can be seen that when resistance occurs, the peak difference generated by the single spring is 72, and when resistance occurs, the peak difference generated by the double spring is 240, which is significantly greater than that of the single spring, which means that the double spring is easier to judge the occurrence of resistance, that is, the sensitivity of resistance detection is better. Similarly, in the fourth experimental data, the peak difference generated by the single spring when resistance occurs is 116, and the peak difference generated by the double spring when resistance occurs is 261. The double spring is also easier to judge the occurrence of resistance, and the sensitivity of resistance detection is better.

Claims

1. A highly sensitive obstruction detection device, characterized in that: It includes a mounting seat, a conductive member, a sensing element and a plurality of spring sheets. The mounting seat is configured to be connected to a transmission component of a lifting column. The plurality of spring sheets are stacked up and down on the mounting seat. The conductive member is configured to pass through all the spring sheets and be connected to a sleeve of the lifting column and transfer the load to the spring sheets. The plurality of spring sheets include a signal spring sheet located on the outermost side and at least one load-bearing spring sheet located between the signal spring sheet and the mounting seat. The sensing element is arranged on the signal spring sheet. The load-bearing spring sheet is configured to bear the load. The signal spring sheet is configured to be deformed when the load of the load-bearing spring sheet changes. The sensing element is configured to output a signal for judging an obstruction situation according to the deformation amount of the signal spring sheet. When the load changes, the load transmitted by the conductive member to all the spring sheets changes, and the spring sheets all deform. The sensing element detects the deformation amount of the signal spring sheet and outputs a signal for judging an obstruction situation.

2. The high-sensitivity obstruction detection device according to claim 1, characterized in that: The thickness of the signal shrapnel is smaller than the thickness of the load-bearing shrapnel.

3. A lifting column, characterized in that: It comprises a telescopic sleeve, a transmission component for driving the sleeve to be telescopic, and the resistance detection device as claimed in claim 1 or 2, wherein the transmission component is arranged in the sleeve, the sleeve has an end plate located at its upper end, the end plate is provided with an opening, and the transmission component is exposed from the opening; the resistance detection device is mounted on the sleeve, and the conductive member is connected to the end plate, and the mounting plate is connected to the transmission component from the opening.

4. The lifting column according to claim 3, characterized in that: A recessed receiving groove is provided on the mounting seat, the bearing spring is arranged in the receiving groove, and the signal spring rests on the upper surface of the bearing spring; a recessed deformation groove is provided on the bottom surface of the receiving groove, and the deformation groove is configured so that when the bearing spring is deformed downward, the deformation groove avoids the bearing spring.

5. The lifting column according to claim 4, characterized in that: The bottom surface of the deformation groove is provided with an avoidance hole which passes through the mounting seat. An elastic member is arranged in the avoidance hole. The conductive member is inserted in the elastic member. The upper end of the elastic member abuts against the bearing spring sheet, and the lower end of the elastic member abuts against the end plate.

6. The lifting column according to claim 5, characterized in that: The mounting seat includes a mounting plate and a convex portion protruding downward from the mounting plate, the convex portion abuts against the transmission assembly downward from the opening; and in the up and down directions, there are gaps between the transmission assembly and the end plate, and between the mounting plate and the end plate.

7. The lifting column according to claim 3, characterized in that: The signal spring sheet and the load-bearing spring sheet have an initial deformation amount under the pressure of the conductive member.

8. The lifting column according to claim 7, characterized in that: The conductive member is a bolt having a head at its upper end and a threaded portion with a diameter smaller than the head. The conductive member passes through the signal shrapnel and the load-bearing shrapnel from top to bottom, and the head applies a pre-tightening force to the signal shrapnel and the load-bearing shrapnel. The threaded portion is threadedly connected to the end plate.

9. The lifting column according to claim 3, characterized in that: The transmission assembly comprises a gear box at the upper end, a connecting hole is provided on the mounting seat, the lower end of the mounting seat abuts against the gear box and is connected to the gear box by bolts arranged in the connecting hole.

10. The lifting column according to claim 3, characterized in that: The sensing element is a piezoelectric piece.

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