Constant force spring assist device and method of making same

Abstract

The application relates to the field of medical robots and discloses a constant-force spring assisting device and a manufacturing method thereof. The constant-force spring assisting device comprises a fixing base, a center wheel and a plurality of constant-force springs which are rotationally connected with the fixing base, the plurality of constant-force springs are symmetrically arranged around the center wheel, the central axes of the plurality of constant-force springs are arranged in parallel with the central axis of the center wheel, each constant-force spring is connected with the center wheel through a traction rope, the center wheel is connected with an external moving part through an output rope, the traction ropes are arranged in parallel with each other, the traction ropes are arranged in parallel with the output rope, the output rope provides a resultant force of the constant forces provided by the plurality of constant-force springs to the constant force assisting force provided by the moving part, the constant-force spring assisting device can provide greater constant force assisting force to the outside under the limited space, the constant-force spring assisting device is helpful to realize miniaturization and modularization, and the demand of more application scenes can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of medical robots, in particular to a constant force spring assisting device and a manufacturing method thereof. BACKGROUND

[0002] Minimally invasive surgery refers to a surgical procedure performed inside the body cavity by using modern medical instruments such as laparoscopes and thoracoscopes and related equipment. Compared with the traditional surgical method, minimally invasive surgery has the advantages of small trauma, light pain, and rapid recovery. However, in minimally invasive surgery, the operation difficulty is greatly increased due to the size limitation of the incision, and the fatigue and tremor of the doctor during the long operation process are amplified, which becomes a key factor restricting the development of minimally invasive surgery technology. With the development of robot technology, a new technology in the field of minimally invasive medical treatment that can overcome the shortcomings and inherit the advantages, i.e. minimally invasive surgery robot technology, has emerged.

[0003] A common minimally invasive surgery robot is composed of a doctor console, a patient surgery platform, and a display device. A surgeon operates an input device at the doctor console.

[0004] The patient surgery platform includes a base, a lifting device, a mechanical arm, and an instrument. Different patient body types and lesion positions require the lifting device and the mechanical arm to be controlled to adjust the position of the instrument to adapt to the patient. The lifting device is required to be gently lifted and have high safety.

[0005] A constant force spring, also known as a constant force spring, is a special tensile spring at present, also known as a spiral spring. The constant force spiral spring includes a spiral part formed by winding an elongated thin metal elastic sheet with equal outer width, and a tensile end extended from the outermost metal sheet of the spiral part. The constant force spiral spring is mainly used in various balance devices requiring constant force output, such as lifting balance devices and motor carbon brush springs. Its characteristic is that the output spring tension is relatively constant, and the tension change is very small. In actual use, the constant force spring is directly stretched to make linear displacement movement, and the constant force spring outputs constant thrust.

[0006] In a Chinese patent document with the patent number CN106499929A and the name "A torque-adjustable lifting device and a display thereof", a "support, a lifting seat, a constant force coil spring, a first pulley, a second pulley, a first connecting rope, and a second connecting rope are disclosed. The constant force coil spring has a winding drum part and a fixed part arranged oppositely. The winding drum part of the constant force coil spring is rotatably arranged on the support, and the fixed part of the constant force spring is fixedly connected with one end of the first connecting rope, and the other end of the first connecting rope is connected with the first pulley." In the above patent document, the space occupied by the constant force spring assisting device is relatively large, and the constant force assistance provided by the constant force spring assisting device is limited, and the use scene is limited. SUMMARY

[0007] The present application aims to provide a constant force spring assisting device and a manufacturing method thereof, so that the constant force spring assisting device provides larger constant force assistance in a limited space, and realizes miniaturization and modularization of the constant force spring assisting device.

[0008] To solve the above technical problems, the present application provides a technical solution as follows: a constant force spring assisting device, comprising a fixed seat, a center wheel and a plurality of constant force springs rotatably connected to the fixed seat, the center axes of the plurality of constant force springs are arranged in parallel with the center axis of the center wheel, each constant force spring is connected to the center wheel through a traction rope, the center wheel is connected to an external moving part through an output rope, the traction ropes do not interfere with each other, and the constant force assistance provided by the output rope to the moving part is the resultant force of the constant forces provided by the plurality of constant force springs.

[0009] Further, the plurality of constant force springs are symmetrically arranged around the center wheel, and the traction ropes are arranged in parallel with each other and with the output rope.

[0010] Further, a plurality of winding grooves are coaxially arranged on the center wheel, and the traction ropes and the output rope are arranged in different winding grooves.

[0011] Further, the output rope is arranged at the central position of the center wheel, and the traction ropes are arranged on both sides of the output rope.

[0012] Further, a part of the traction rope is pre-wound on the constant force spring, and the pre-wound length is the same as the maximum stroke of the moving part; a part of the output rope is pre-wound in the winding groove, and the pre-wound length is the same as the maximum stroke of the moving part.

[0013] Further, the winding diameters of the traction rope on the constant force spring, the traction rope on the center wheel, and the output rope on the center wheel are the same.

[0014] Further, the winding direction of the traction rope on the constant force spring is opposite to the winding direction of the traction rope on the center wheel, and the traction rope extending between the center wheel and the constant force spring is tangentially arranged with the center wheel and the constant force spring.

[0015] Further, the traction rope and the output rope are steel wire ropes, and the diameters of the steel wire ropes are the same.

[0016] Further, the constant force spring has four, and the allowable tension of the steel wire rope is at least greater than 32 times the constant force provided by a single constant force spring.

[0017] Further, the constant force spring has eight, and each two constant force springs are coaxially arranged as a group, and the allowable tension of the steel wire rope is at least greater than 64 times the constant force provided by a single constant force spring.

[0018] To solve the above technical problems, the application further provides a constant force spring assisting device manufacturing method, comprising the following steps:

[0019] Selecting the specifications and number of constant force springs according to the required constant force assistance;

[0020] Rotatingly arranging a plurality of constant force springs and a center wheel on the same fixed seat, the central axis of the constant force spring being parallel to the central axis of the center wheel;

[0021] Each constant force spring is connected to the center wheel through a traction rope, the center wheel is connected to the moving part through an output rope, the traction ropes do not interfere with each other, and the constant force assistance provided to the moving part through the output rope is the resultant force of the constant forces provided by the plurality of constant force springs.

[0022] Further, the plurality of constant force springs are symmetrically arranged around the center wheel, and the traction ropes do not interfere with each other.

[0023] Further, a plurality of winding grooves are coaxially arranged on the center wheel, the output rope is arranged in the center winding groove, and the traction ropes are arranged in the winding grooves on both sides of the output rope.

[0024] Further, a part of the traction rope is pre-wound on the constant force spring, and the pre-wound length is the same as the maximum stroke of the moving part; a part of the output rope is pre-wound in the winding groove, and the pre-wound length is the same as the maximum stroke of the moving part.

[0025] Further, the winding direction of the traction rope on the constant force spring is opposite to the winding direction of the traction rope on the center wheel, and the traction rope extending between the center wheel and the constant force spring is tangentially arranged with the center wheel and the constant force spring.

[0026] Further, the traction rope and the output rope are steel wire ropes of the same specifications, and the allowable tension of the steel wire rope is at least greater than 8 times the resultant force of the constant forces provided by the plurality of constant force springs.

[0027] The constant force spring assisting device and its manufacturing method provided by the application can provide greater constant force assistance to the outside within a limited space by symmetrically arranging a plurality of constant force springs around the center wheel, which helps to realize the miniaturization and modularization of the constant force spring assisting device, meet the needs of more application scenarios, and effectively guarantee the stability and safety factor of the constant force spring assisting device by selecting and setting the allowable tension of the traction rope and the steel wire rope. BRIEF DESCRIPTION OF DRAWINGS

[0028] One or more embodiments are illustrated by way of example in the drawings hereof, which are not intended to limit the embodiments and the illustration in the drawings does not constitute any limitation of the embodiments, and elements having the same reference numerals in the drawings represent similar elements unless otherwise specified, and the drawings are not limited in scale.

[0029] Figure 1 is a schematic diagram of the overall structure of the constant force spring assisting device in one embodiment of the application;

[0030] Figure 2 is a schematic diagram of the overall structure of the constant force spring assisting device in one embodiment of the application after removing the fixed seat;

[0031] Figure 3 is a schematic diagram of the setting position of the traction rope and the output rope in one embodiment of the application from the top view;

[0032] Figure 4 is a schematic diagram of the setting position of the traction rope and the output rope in one embodiment of the application from the side view;

[0033] Figure 5 is a schematic diagram of the setting position of the traction rope and the output rope in another embodiment of the application from the side view.

[0034] Legend of reference numerals: 1, fixed seat; 2, center wheel; 21, winding groove; 3, constant force spring; 4, output rope; 41, wire outlet end; 5, traction rope; 6, guide wheel. DETAILED DESCRIPTION

[0035] To make the purpose, technical solutions and advantages of the application clearer, the embodiments of the application will be described in detail below with reference to the drawings. However, those skilled in the art can understand that in the embodiments of the application, many technical details are presented to make the readers better understand the present application. However, the technical solutions claimed by the claims of the present application can be realized even without these technical details and various changes and modifications based on the following embodiments.

[0036] In the application of the constant force spring, the constant force spring can be arranged on the lifting mechanism to provide assistance and protect the motor. Generally, the wire outlet end of the constant force spring is connected to the moving part of the lifting mechanism. When the motor drives the moving part to rise, the constant force spring has been pulled out to a certain length. According to the characteristics of the constant force spring, when the moving part is subsequently raised, the constant force spring keeps providing a constant pulling force, thereby providing a constant assistance for the rising. When the moving part is lowered, on one hand, the moving part is lowered under the action of the motor and gravity, and on the other hand, the moving part is subjected to a constant and reverse force from the constant force spring, thereby effectively preventing the moving part from falling too fast and reducing the accident rate. On the other hand, the constant force spring effectively protects the motor and can also offset the gravity of the mechanism to serve as a counter-acting auxiliary device. In order to obtain higher constant force assistance, the constant force springs are often used in combination.

[0037] As Figures 1-5 shown, the technical scheme provided by the present application relates to a constant force spring assisting device, which comprises a fixed seat 1, a center wheel 2 and a plurality of constant force springs 3 arranged in rotation connection with the fixed seat 1, the central shafts of the plurality of constant force springs 3 are arranged in parallel with the central shaft of the center wheel 2, each constant force spring 3 is connected with the center wheel 2 through a traction rope 5, the center wheel 2 is connected with an external moving part through an output rope 4, the traction rope 5 and the traction rope 5, and the traction rope 5 and the output rope 4 are not interfered with each other, and the constant force assisting force provided by the output rope 4 to the moving part is the resultant force of the constant force provided by the plurality of constant force springs 3.

[0038] Preferably, the plurality of constant force springs 3 are arranged in symmetry with the center wheel 2 as the center, and the traction rope 5 and the traction rope 5, and the traction rope 5 and the output rope 4 are arranged in parallel. A plurality of winding grooves 21 are coaxially arranged on the center wheel 2, one end of the traction rope 5 is fixedly connected with one end of the constant force spring 3, and the other end is fixedly connected with the winding groove 21; each traction rope 5 is arranged in a different winding groove 21; one end of the output rope 4 is fixedly connected with the winding groove 21, and the other end is connected with the moving part (not shown in the drawing), the end connected with the moving part is the outgoing end 41, and the output rope 4 is arranged in a winding groove 21 different from the traction rope 5; preferably, the outgoing end 41 can be stopped and limited by the fixed seat 1 along the movement direction of the moving part, and when the outgoing end 41 is stopped on the fixed seat 1, the constant force spring 3 is in a pre-stretching state, so as to ensure that the output rope 4 keeps the constant force state of the constant force spring 3 when moving with the moving part.

[0039] As Figures 1-4As shown, the first embodiment of the present application relates to a constant force spring assisting device, comprising a fixed seat 1, and a center wheel 2 rotationally connected with the fixed seat 1, the center wheel 2 is provided with 5 wire grooves 21, 4 constant force springs 3 are symmetrically arranged around the center wheel 2, the central axis of the constant force spring 3 is parallel to the central axis of the center wheel 2, the constant force spring 3 is rotationally connected with the fixed seat 1 through a pin shaft, each constant force spring 3 is fixedly connected with a traction rope 5, the other end of the traction rope 5 is fixedly connected with the wire groove 21, the traction rope 5 extending between the center wheel 2 and the constant force spring 3 is tangentially arranged with the center wheel 2 and the constant force spring 3, the traction rope 5 is wound in the wire groove 21 of the center wheel 2 and / or on the constant force spring 3 with the rotation of the center wheel 2 and the constant force spring 3, the winding diameter of the traction rope 5 on the center wheel 2 is equal to the winding diameter of the traction rope 5 on the constant force spring 3, the traction ropes 5 are arranged in parallel, one end of an output rope 4 is fixedly arranged in the wire groove 21 in the middle of the center wheel 2, the other end is connected with a moving part, the output rope 4 is arranged in parallel with the traction rope 5, preferably, a guide wheel 6 is further arranged between the center wheel 2 and the moving part, the output rope 4 is connected with the moving part after changing direction through the guide wheel 6, which can better adapt to the movement track of the moving part. The traction rope 5 and the output rope 4 are steel wire ropes, and the diameters of the steel wire ropes are consistent. Preferably, the end of the traction rope 5 and the output rope 4 connected with the wire groove 21 is fixedly sleeved with a sleeve, the bottom of the wire groove 21 is provided with a limiting hole, the limiting hole is hiddenly arranged at the bottom of the wire groove 21, the sleeve is accommodated in the limiting hole and is fixedly resisted by using a fastener, which ensures the firmness of the traction rope 5 and the output rope 4 connected with the wire groove 21, and can reduce the abrasion of the traction rope 5 and the output rope 4 during movement.

[0040] When in use, the pulling stroke of the setting constant force spring assisting device output rope 4 is L, which is equal to the maximum stroke of the moving part, wherein the winding diameter of the traction rope 5 on the constant force spring 3 is d, and the winding diameter of the traction rope 5 on the center wheel 2 is d, in the initial stage, one end of the traction rope 5 is fixed with one end of the constant force spring 3, and a part of the traction rope 5 is pre-wound on the constant force spring 3, and the total length of the pre-winding is L, and the corresponding pre-winding number is n, wherein: L = n x πd, the other end of the traction rope 5 is fixedly connected with the winding groove 21; one end of the output rope 4 is fixedly connected with the winding groove 21, and a part of the output rope 4 is pre-wound in the winding groove 21 of the center wheel 2, and the total length of the pre-winding is L, and the corresponding pre-winding number is n, wherein: L = n x πd, the other end of the output rope 4 is connected with the moving part, and the output rope 4 is pulled under the driving of the moving part, the center wheel 2 is driven to rotate counterclockwise, the center wheel 2 rotates to pull the traction rope 5, and the constant force spring 3 is driven to rotate clockwise around the center shaft, the constant force spring 3 is unwound and stretched, and the traction rope 5 connected with the plurality of constant force springs 3 is connected with the same center wheel 2, therefore, the force output by the constant force spring assisting device through the output rope 4 is the resultant force of the constant forces provided by the plurality of constant force springs 3, which can effectively increase the constant force assisting force on the moving part.

[0041] When the constant force spring 3 is set to 4, the allowable tension of the output rope 4 is at least greater than 8 times the resultant force of the constant forces provided by the 4 constant force springs 3, that is, the allowable tension of the output rope 4 is at least 32 times the constant force of a single constant force spring 3, according to the allowable tension of the output rope 4, the corresponding output rope 4 diameter is selected, the traction rope 5 and the output rope 4 are steel wire ropes with the same diameter specification, and the friction coefficients between the steel wire rope and the constant force spring and the center wheel are comprehensively considered, preferably, the allowable tension of the output rope 4 and the traction rope 5 is set to 40 times the constant force of a single constant force spring 3, so as to increase the safety factor. For example, when the constant force of a single constant force spring 3 is 30N, the allowable tension of the output rope 4 and the traction rope 5 is set to 1200N, it should be noted that the friction coefficients between the steel wire rope and the constant force spring and the center wheel are related to the material and connection mode thereof, and the allowable tension of the traction rope can be adjusted according to the size of the friction coefficient.

[0042] As Figure 5As shown, the second embodiment of the present application relates to a constant force spring assisting device. The second embodiment is substantially the same as the first embodiment, and the main difference is that in order to increase the constant force assistance provided by the constant force spring assisting device, the number of constant force springs 3 is increased to 8, wherein each two constant force springs 3 are coaxially arranged in a group, and the corresponding wire grooves 21 of the center wheel 2 are arranged in at least 9, wherein the central wire groove 21 is the wire groove 21 of the output rope 4, and the allowable tension of the output rope 4 and the traction rope 5 is at least 8 times the constant force provided by the 8 constant force springs 3, that is, the allowable tension of the output rope 4 is at least 64 times the constant force of a single constant force spring 3, and preferably, the allowable tension of the output rope 4 and the traction rope 5 is set to be 80 times the constant force of a single constant force spring 3.

[0043] The present application also provides a method for manufacturing a constant force spring assisting device, comprising the following steps:

[0044] First, select the specifications and number of constant force springs 3 according to the required constant force, and preferably, the specifications of the plurality of constant force springs 3 are the same;

[0045] Then, the constant force spring 3 and the center wheel 2 are arranged on the same fixed seat 1, and the center axis of the constant force spring 3 is parallel to the center axis of the center wheel 2; preferably, the plurality of constant force springs 3 are symmetrically arranged around the center wheel 2 as the center;

[0046] Each constant force spring 3 is connected to the center wheel 2 by a traction rope 5, and the center wheel 2 is connected to the moving part by an output rope 4, and the traction ropes do not interfere with each other, and the traction ropes do not interfere with the output rope, and the constant force assistance provided by the output rope 4 to the moving part is the resultant force of the constant forces provided by the plurality of constant force springs 3. Preferably, the traction ropes are arranged in parallel.

[0047] Preferably, a plurality of wire grooves 21 are coaxially arranged on the center wheel 2, the output rope 4 is arranged in the central wire groove 21, and the traction ropes 5 are arranged in the wire grooves 21 on both sides of the output rope 4;

[0048] In one embodiment, a part of the traction rope 5 is pre-wound on the constant force spring 3, the other end of the traction rope 5 is fixedly arranged in the wire groove 21, the winding direction of the traction rope 5 on the constant force spring 3 is opposite to the winding direction of the traction rope 5 on the center wheel 2, and the traction rope 5 extending between the center wheel 2 and the constant force spring 3 is tangentially arranged with the center wheel 2 and the constant force spring 3; a part of the output rope 4 is pre-wound in the wire groove 21, and the other end of the output rope 4 is connected to the moving part, wherein the pre-wound length of the traction rope 5 on the constant force spring 3 and the pre-wound length of the output rope 4 in the wire groove 21 are the same as the moving stroke of the moving part.

[0049] The traction rope 5 and the output rope 4 are steel ropes of the same specification, and the allowable tension of the steel rope is at least greater than 8 times the total constant force provided by the plurality of constant force springs 3, preferably, the allowable tension of the steel rope is set to be 10 times the total constant force provided by the plurality of constant force springs 3, in an embodiment, the constant force springs 3 are set to be 4, and the allowable tension of the traction rope 5 and the output rope 4 is set to be 40 times that of a single constant force spring 3.

[0050] The constant force spring assisting device and the manufacturing method thereof provided by the present application, by the layout scheme of symmetrically arranging a plurality of constant force springs around the center wheel, the constant force spring assisting device can provide greater constant force assistance in a limited space, which is helpful to realize the miniaturization and modularization of the constant force spring assisting device, and meet the needs of more application scenarios, and by the selection and setting of the allowable tension of the traction rope and the steel rope, the stability and safety factor of the constant force spring assisting device are effectively guaranteed.

[0051] Those skilled in the art can understand that the above-mentioned embodiments are specific embodiments for realizing the present application, and in actual application, various changes can be made in form and details without departing from the spirit and scope of the present application.

Claims

1. A constant force spring assist device, characterized in that, It includes a fixed base, a central wheel rotatably connected to the fixed base, and multiple constant force springs. The central axes of the multiple constant force springs are arranged parallel to the central axis of the central wheel. Each constant force spring is connected to the central wheel through a traction rope. The central wheel is connected to an external moving part through an output rope. The traction ropes do not interfere with each other or with the output rope. The constant force assistance provided by the output rope to the moving part is the resultant force of the constant forces provided by the multiple constant force springs. The plurality of constant force springs are symmetrically arranged around the central wheel, and the traction ropes are arranged in parallel with each other and with the output rope. The central wheel is coaxially provided with multiple winding grooves, and the traction rope and output rope are respectively arranged in different winding grooves; The output rope is located in the center of the central wheel, and the traction ropes are located on both sides of the output rope.

2. The constant force spring assist device according to claim 1, characterized in that, A portion of the traction rope is pre-wound onto a constant force spring, and the length of the pre-wound is the same as the maximum stroke of the moving component; a portion of the output rope is pre-wound into a winding groove, and the length of the pre-wound is the same as the maximum stroke of the moving component.

3. The constant force spring assist device according to claim 2, characterized in that, The winding diameter of the traction rope on the constant force spring, the winding diameter of the traction rope on the central pulley, and the winding diameter of the output rope on the central pulley are all the same.

4. The constant force spring assist device according to claim 2, characterized in that, The traction rope is wound in the opposite direction to the constant force spring, and the traction rope extending between the central wheel and the constant force spring is tangential to both the central wheel and the constant force spring.

5. The constant force spring assist device according to any one of claims 1-4, characterized in that, The traction rope and the output rope are steel wire ropes with the same diameter.

6. The constant force spring assist device according to claim 5, characterized in that, There are four constant force springs, and the allowable tensile force of the wire rope is at least 32 times greater than the constant force provided by a single constant force spring.

7. The constant force spring assist device according to claim 5, characterized in that, There are eight constant force springs, with each pair of constant force springs arranged coaxially. The allowable tensile force of the wire rope is at least 64 times greater than the constant force provided by a single constant force spring.

8. A method for manufacturing a constant force spring assist device, characterized in that, Includes the following steps: Select the specifications and quantity of constant force springs according to the required constant force assistance; Multiple constant force springs and a central wheel are rotatably mounted on the same fixed base, with the central axis of the constant force springs being parallel to the central axis of the central wheel. Each constant force spring is connected to the central wheel via a traction rope, and the central wheel is connected to the moving part via an output rope. The traction ropes do not interfere with each other, and the output ropes do not interfere with each other. The constant force assistance provided to the moving part through the output rope is the resultant force of the constant forces provided by multiple constant force springs. The multiple constant force springs are symmetrically arranged around the central wheel, and the traction ropes are arranged in parallel with each other and the output ropes are arranged with each other. The central wheel is coaxially provided with multiple winding grooves, the output rope is centrally located in the central winding groove, and the traction ropes are all located in the winding grooves on both sides of the output rope.

9. The method for manufacturing the constant force spring assist device according to claim 8, characterized in that, It also includes pre-winding a portion of the traction rope onto a constant force spring, the pre-winding length being the same as the maximum stroke of the moving component; and pre-winding a portion of the output rope into a winding groove, the pre-winding length being the same as the maximum stroke of the moving component.

10. The method for manufacturing a constant force spring assist device according to claim 9, characterized in that, The traction rope is wound in the opposite direction to the constant force spring, and the traction rope extending between the central wheel and the constant force spring is tangential to both the central wheel and the constant force spring.

11. The method for manufacturing a constant force spring assist device according to any one of claims 8-10, characterized in that, The traction rope and the output rope are steel wire ropes of the same specification, and the allowable tensile force of the steel wire rope is at least 8 times greater than the resultant force of the constant force provided by multiple constant force springs.

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