TWI860255B - Linear actuator with protection mechanism - Google Patents

Abstract

A linear actuator with protection mechanism includes a motor box, a driving mechanism, a transmission mechanism and a protection structure. The motor box having a box body. The box body having a base plate. The base plate having a hole. The driving mechanism is arranged in the box body. The transmission mechanism includes the movement, a bearing, a locating seat and a fixing element. The movement is threaded the hole and connected to the driving mechanism. The locating seat having an extension plate. The extension plate having a through-hole. The bearing is mounted on the locating seat and socketed to the movement, and the fixing element are perforated to the base plate. The fixing element having a head. The protective structure is sleeved with a fixing element and is arranged between the base plate and the head.

Description

Linear actuator with protection mechanism

This application relates to the technical field of a linear actuator device, particularly a linear actuator device with a protection mechanism.

Linear actuators are used in electric beds, nursing beds, hospital beds, electric lifting tables or chairs for adjusting height or elevation angles, which is quite common. When a user encounters an obstacle during the adjustment of the aforementioned equipment, the user will come into contact with the obstacle and generate an interaction force, which will be transmitted to the linear actuator. If the linear actuator does not stop operating immediately, the linear actuator will be damaged by the obstacle; if the obstacle is a human body, it will cause injury to the human body.

In order to solve the above problems, the industry has set up an obstruction protection mechanism capable of detection in the linear actuator. Among the current obstruction protection mechanisms with higher sensitivity, an element that can realize the conversion between pressure signals and electrical signals is used as an obstruction detection element. However, when the deformation at the installation position of the obstruction detection element is small, the generated deformation stress is not enough to cause the obstruction detection element to generate an obstruction alarm. Only when the linear actuator and the obstacle collide for a period of time can a sufficiently large deformation stress be generated to trigger the obstruction detection element. In addition, the obstruction response speed of the existing obstruction protection mechanism is too slow, so it cannot meet the actual use requirements at the current stage.

One purpose of the present application is to provide a linear actuating device with a protection mechanism, which can interrupt movement after being blocked during movement, thereby reducing collision damage to objects and improving safety in use.

In order to achieve the above-mentioned purpose, the present application provides a linear actuator with a protection mechanism, including a motor box, a driving mechanism, a transmission mechanism and a protection structure, wherein the motor box includes a box body, the box body has a bottom plate, and a through hole is provided on the bottom plate; the driving mechanism is arranged in the box body; the transmission mechanism includes a movement, a bearing, a placement seat and a fixing element, the movement passes through the through hole and is connected to the driving mechanism, the placement seat has an extension plate, the extension plate has a through hole, the bearing is arranged on the placement seat and sleeved with the movement, the fixing element passes through the through hole and is fixed to the bottom plate, and the fixing element has a head; the protection structure sleeves the fixing element and is configured between the bottom plate and the head.

The present application also has the following effects. Since the perforations of the extension plate are offset from the bearing socket, it has a better amplification effect when the movement encounters resistance, so that the resistance detection function is highly sensitive and has higher safety and reliability. When encountering an obstacle during the lifting and moving process, the movement will be subjected to an axial force and transmitted to the placement seat, so that the extension plate is stressed and compresses the protective structure, causing the elastic body to deform, thereby triggering the pressure sensor to measure the resistance. Since the pressure sensor can be set at different positions of the elastic body according to actual use requirements, it is respectively applicable to a tension-type linear actuating device, a thrust-type linear actuating device or a push-pull type linear actuating device, which further increases its diversity of use. When the pressure sensor fails, the fixing element only needs to be removed from the base plate to remove or replace the pressure sensor, which is more convenient to use.

The detailed description and technical contents of this application are described below with the help of drawings. However, the attached drawings are only provided for reference and description and are not used to limit this application.

Please refer to Figures 1 to 7. The present application provides a linear actuator device with a protection mechanism, which is applied to an electric table 8. The electric table 8 includes at least one lifting column 81 and a table top 82. The lifting column 81 includes a linear actuator device 1 with a protection mechanism and a telescopic tube assembly 811. The linear actuator device 1 with a protection mechanism mainly includes a motor box 10, a driving mechanism 20, a transmission mechanism 30 and a protection structure 40.

Please refer to Figures 2 to 5. The motor box 10 is roughly rectangular, and mainly includes a box body 11 and a cover body 12. The box body 11 has a bottom plate 111 and a plurality of side plates 112 connected to the bottom plate 111. A cavity 113 is jointly surrounded by the bottom plate 111 and the side plates 112. A through hole 114 and a plurality of screw holes 115 are provided in the bottom plate 111. In addition, a plurality of buckle grooves 116 are provided in each side plate 112. The cover body 12 is a cover corresponding to the box body 11. A plurality of buckle hooks 121 corresponding to the buckle grooves 116 are extended around the cover body 12.

The driving mechanism 20 is accommodated in the cavity 111 of the box body 11, and mainly includes a motor 21 and a reduction gear set 22. The motor 21 is a component that can generate forward and reverse rotation. The reduction gear set 22 is connected to one end of the motor 21, and it can be a type of worm gear.

The transmission mechanism 30 mainly includes a movement 31, a bearing 32, a placement seat 33 and two fixing elements 34. The movement 31 mainly includes a lead screw 311, a hollow tube 312 and a nut 313. The nut 313 is fixed to one end of the hollow tube 312 and is threadedly connected with the lead screw 311 for transmission. The lead screw 311 penetrates into the interior of the box body 11 from the aforementioned through hole 112 to connect with the driving mechanism 20. The aforementioned driving mechanism 20 is fixed on the top of the placement seat 33 by passing through each screw 23. The placement seat 33 has a bearing socket 331 and two extension plates 332 protruding from the bearing socket 331 in opposite directions. A through hole 333 is respectively provided at the end of each extension plate 332. The fixing element 34 of this embodiment is a screw having a head 341. The bearing 32 is set in the bearing socket 331 and sleeved on the lead screw 311. The placement seat 33 is fixed by passing through each through hole 333 and locking each screw hole 115 of each fixing element 34, and the head 341 of the fixing element 34 is used to press the top of the extension plate 332.

Please continue to refer to Figures 6 and 7. The protection structure 40 of this embodiment is sleeved on the aforementioned fixing element 34 and is located between the bottom plate 111 and the extension plate 332. It mainly includes an elastic body 41 and a pressure-sensitive sensor 42. The elastic body 41 can be a rubber buffer having a hole 411. The pressure sensor 42 also has a hole 421, which is adhered to the lower surface of the elastic body 41. The elastic body 41 and the pressure sensor 42 are mounted on the aforementioned fixing element 34 through their holes 411 and 421, and are clamped between the extension plate 332 and the bottom plate 111. In this way, when the elastic body 41 is compressed, a pre-stress is generated in the pressure sensor 42. The aforementioned configuration structure is applicable to a thrust-type linear actuator.

In one embodiment, the pressure sensor 42 may be a resistive strain gauge pressure sensor. When a force is applied to the elastic body 41, the pressure sensor 42 is deformed, thereby causing a change in resistance. The change in resistance is processed by a control device (not shown) and output in the form of an electrical signal. Common types include metal resistive strain gauges and semiconductor strain gauges.

When the lifting column 81 encounters an obstacle during the upward movement, the pressure sensor 42 will feel the pre-pressure of the elastic body 41. When the lifting column 81 increases the load, the extension plate 332 of the placement seat 33 will further compress the elastic body 41, the pressure on the pressure sensor 42 increases, and its resistance value decreases. When the lifting column 81 reduces the load, the compression of the elastic body 41 by the extension plate 332 of the placement seat 33 decreases, the pressure on the pressure sensor 42 decreases, and its resistance value increases.

When the load on the lifting column 81 changes, the compression amount of the elastic body 41 by the extension plate 332 of the placement seat 33 changes, thereby causing the pressure of the elastic body 41 on the pressure sensor 42 to change. When the pressure of the pressure sensor 42 changes, the resistance value changes accordingly; the control device is used to cut off the power or rotate the motor 21 in the opposite direction, thereby protecting the lifting column 81.

Please refer to Figures 8 and 9. The linear actuator with a protection mechanism of this embodiment is roughly the same as the structure of the first embodiment described above, and the difference lies in that: there are two protection structures 40, which are respectively arranged between the two extension plates 332 of the placement seat 33 and the bottom plate 111, and each pressure sensor 42 is respectively adhered to the upper surface of each elastic body 41, and each elastic body 41 and each pressure sensor 42 are respectively mounted on each fixing element 34 through their holes 411 and 421, and are clamped between each extension plate 332 and the bottom plate 111. The aforementioned configuration structure is applicable to a tension-type linear actuator.

Please refer to FIG. 10 and FIG. 11 . The difference between the linear actuator with a protection mechanism of this embodiment and the aforementioned embodiments is that the protection structure 40 mainly includes an elastic body 41A and a pressure sensor 42. The elastic body 41A includes a first elastic pad 412 and a second elastic pad 413. The first elastic pad 412 is disposed between the extension plate 332 of the placement seat 33 and the bottom plate 111 of the box body 11, and the second elastic pad 413 is disposed between the head 341 of the fixing element 34 and the extension plate 332 of the placement seat 33. The pressure sensor 42 is disposed between the head 341 of the fixing element 34 and the second elastic pad 413.

Please refer to Figures 12 and 13. The difference between the linear actuator with a protection mechanism of this embodiment and the aforementioned embodiments is that: the protection structure 40 mainly includes an elastic body 41B and a pressure sensor 42. The elastic body 41B has an embedding groove 414, and the through hole 333 of the extension plate 332 is embedded through the embedding groove 414, so that a portion of the elastic body is formed on the upper and lower sides of the extension plate 332, respectively. The pressure sensor 42 is arranged between the head 341 of the fixing element 34 and the upper surface of the elastic body 41B.

Please refer to Figures 14 and 15. The difference between the linear actuator with a protection mechanism of this embodiment and the aforementioned fourth embodiment is that: the protection structure 40 also includes a plunger 43, which has a hollow column 431 and a flange 432 radially extending from one end of the hollow column 431, wherein the hollow column 431 passes through the hole 411 of the aforementioned elastic body 41B, and the elastic body 41B is positioned between the flange 432 and the bottom plate 111 of the box body 11, and the pressure sensor 42 is arranged between the flange 432 of the plunger 43 and the upper surface of the elastic body 41B.

Please refer to Figures 16 and 17. The difference between the linear actuator with a protection mechanism of this embodiment and the aforementioned third embodiment is that: the protection structure 40 mainly includes an elastic body 41A and a pressure sensor 42, the elastic body 41A includes a first elastic pad 412 and a second elastic pad 413, the first elastic pad 412 is arranged between the extension plate 332 of the placement seat 33 and the bottom plate 111 of the box body 11, and the second elastic pad 413 is arranged between the head 341 of the fixing element 34 and the extension plate 332 of the placement seat 33; wherein the pressure sensor 42 is configured between the second elastic pad 413 and the extension plate 332 of the placement seat 33.

Please refer to Figure 18. The difference between the protective structure 40A of this embodiment and the aforementioned embodiments is that the protective structure 40A mainly includes an elastic body 41 and a pressure sensor 42. The pressure sensor 42 is embedded in the elastic body 41, and the hole 421 of the pressure sensor 42 is configured corresponding to the hole 411 of the elastic body 41. The aforementioned configuration structure is applicable to a push-pull type linear actuator.

The above description is only the preferred embodiment of the present application and is not intended to limit the patent scope of the present application. Other equivalent variations that utilize the patent spirit of the present application should all fall within the patent scope of the present application.

1: Linear actuator 10: Motor box 11: Box body 111: Bottom plate 112: Side plate 113: Receptacle 114: Through hole 115: Screw hole 116: Buckle groove 12: Cover body 121: Buckle hook 20: Driving mechanism 21: Motor 22: Speed reduction gear set 23: Screw 30: Transmission mechanism 31: Movement 311: Lead screw 312: Hollow tube 313: Nut 32: Bearing 33: Placement seat 331: Bearing nest 332: Extension plate 333: Perforation 34: Fixing element 341: Head 40, 40A: Protective structure 41, 41A, 41B: Elastic body 411: Hole 412: First elastic pad 413: Second elastic pad 414: Groove 42: Pressure sensor 421: Hole 43: Plunger 431: Hollow column 432: Flange 8: Electric table 81: Lifting column 811: Telescopic tube assembly 82: Table top

FIG. 1 is a schematic diagram of the first embodiment of the present application applied to an electric table assembly.

FIG. 2 is a perspective view of the first embodiment of the present application.

FIG3 is an exploded view of the first embodiment of the present application.

FIG. 4 is a top view of the first embodiment of the present application.

FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 4 .

FIG. 6 is a cross-sectional view taken along line 6-6 of FIG. 4 .

FIG. 7 is an enlarged view of a portion of FIG. 6 .

FIG8 is an exploded view of the second embodiment of the present application.

FIG. 9 is a cross-sectional view of the second embodiment of the present application.

FIG. 10 is an exploded view of the third embodiment of the present application.

FIG. 11 is a cross-sectional view of the third embodiment of the present application.

FIG. 12 is an exploded view of the fourth embodiment of the present application.

FIG. 13 is a cross-sectional view of the fourth embodiment of the present application.

FIG. 14 is an exploded view of the fifth embodiment of the present application.

FIG. 15 is a cross-sectional view of the fifth embodiment of the present application.

FIG. 16 is an exploded view of the sixth embodiment of the present application.

FIG. 17 is a cross-sectional view of the sixth embodiment of the present application.

FIG. 18 is a cross-sectional view of another embodiment of the protective structure of the present application.

1: Linear actuator

10: Motor box

11: Box body

111: Base plate

112: Side panels

113: Chamber

114:Through hole

115: screw hole

116: Buckle slot

12: Cover

121: Hook

20: Driving mechanism

21: Motor

22: Reduction gear set

23: Screws

30: Transmission mechanism

31: Movement

311:Lead screw

312: Hollow tube

313: Nut

32: Bearings

33: Placement seat

331: Bearing socket

332: Extension plate

333:Piercing

34:Fixed components

341:Head

40: Protective structure

41: Elastic body

411: Hole

42: Pressure sensor

421: Hole

81: Lifting column

811: Telescopic tube assembly

Claims (14)

A linear actuator with a protection mechanism, comprising: A motor box, comprising a box body, the box body having a bottom plate, and a through hole is provided on the bottom plate; A driving mechanism, arranged in the box body; A transmission mechanism, comprising a movement, a bearing, a placement seat and a fixing element, the movement passes through the through hole and is connected to the driving mechanism, the placement seat has an extension plate, the extension plate has a through hole, the bearing is arranged on the placement seat and sleeved with the movement, the fixing element passes through the through hole and is fixed to the bottom plate, and the fixing element has a head; and A protection structure, sleeved on the fixing element and arranged between the bottom plate and the head. A linear actuator with a protection mechanism as described in claim 1, wherein the placement seat also has a bearing socket, the extension plate extends from the bearing socket, and the bearing is disposed in the bearing socket. A linear actuator with a protection mechanism as described in claim 2, wherein the protection structure includes an elastic body and a pressure sensor, and the elastic body and the pressure sensor are located between the base plate and the extension plate and stacked on each other. A linear actuator with a protection mechanism as described in claim 3, wherein the pressure sensor is located between the base plate and the elastic body. A linear actuator with a protection mechanism as described in claim 3, wherein the pressure sensor is located between the elastic body and the extension plate. A linear actuator with a protection mechanism as described in claim 2, wherein the extension plate and the protection structure are both plural. A linear actuator with a protection mechanism as described in claim 2, wherein the protection structure includes a first elastic pad and a second elastic pad, the first elastic pad is located between the extension plate and the base plate, and the second elastic pad is arranged between the head and the extension plate. A linear actuator with a protection mechanism as described in claim 7, wherein the protection structure also includes a pressure sensor located between the head and the second elastic pad. A linear actuator with a protection mechanism as described in claim 7, wherein the protection structure also includes a pressure sensor, which is located between the second elastic pad and the extension plate. A linear actuator with a protection mechanism as described in claim 2, wherein the protection structure includes an elastic body and a pressure sensor, the elastic body has a groove, and the extension plate is embedded in the groove through the through hole. A linear actuator with a protection mechanism as described in claim 10, wherein the pressure sensor is located between the head and the elastic body. A linear actuator with a protection mechanism as described in claim 10, wherein the protection structure further includes a plunger having a hollow column and a flange radially extending from one end of the hollow column, the hollow column passes through the elastic body and is positioned between the flange and the base plate, and the pressure sensor is arranged between the flange and the elastic body. A linear actuator with a protection mechanism as described in claim 1, wherein the protection structure includes an elastic body and a pressure sensor, and the pressure sensor is embedded in the elastic body. A linear actuator with a protection mechanism as described in claim 13, wherein the elastic body has a hole, the pressure sensor has a hole, and the hole of the pressure sensor is configured to correspond to the hole of the elastic body.