Light flexible two-force rod mechanism

Abstract

The invention discloses a light flexible two-force-rod mechanism which comprises a two-force thin and long rod, the two ends of the two-force thin and long rod are provided with thin necks with the diameter smaller than that of the two-force thin and long rod, the two ends of the two-force thin and long rod obtain preset bending rigidity at the thin necks, and therefore flexible two-freedom-degree rotation within a preset rotation angle range is obtained. The two ends of the two-force slender rod are provided with steel balls connected to the slender neck in a fastened mode, and the two ends of the two-force slender rod are installed on a piece to be installed through cooperation of the pressing caps and the steel balls. The light flexible gapless two-force-rod mechanism is achieved, the strength of the two-force-rod mechanism and the flexibility of the flexible hinge can be designed according to actual working requirements, and the two-force-rod mechanism has the advantages of being simple in structure, symmetrical, compact, low in cost, convenient to install and adjust and the like and is particularly suitable for the field of precise supporting of optical mirror faces.

Description

Technical Field

[0001] The invention relates to a light flexible two-force rod mechanism based on an elastic thin rod, and is particularly suitable for the technical field of optical mirror precision support. Background Art

[0002] The two-force rod is a mechanism that only transmits unidirectional force. It only transmits a single force in a certain direction, and does not introduce forces and moments in other directions. This characteristic of the two-force rod is also a requirement for the design of the two-force rod mechanism. The two-force rod mechanism is widely used in the design of optical mirror support systems. Existing optical mirror axial support systems such as Figure 1 As shown, it mainly includes a frame 15, a lever 16, an axial support floating frame 14, an optical mirror 13, a spherical pair 17, and a two-force rod 18. Traditionally, the two ends of the two-force rod generally adopt a spherical pair-ball seat and ball head-structure, such as a joint bearing, to eliminate torque and lateral force as much as possible. However, there is inevitably friction between the mating surfaces of this ball seat-ball head bearing structure. When the two-force rod rotates, the torque caused by friction is uncertain, which causes uncertainty in the surface shape of the supported optical mirror; after the force changes direction, the spherical pair often has a gap, which causes uncertainty in the position and posture of the supported optical mirror. On the other hand, the two-force rod mechanism based on the traditional spherical pair is heavy, has a greater impact on the precision optical surface shape, has more parts, and has a more complicated installation process. In addition, the traditional spherical pair also requires lubrication and regular maintenance, and grease is not friendly to the optical system and its clean environment requirements. Therefore, the two-force rod mechanism based on the traditional spherical pair is not suitable for the design of a precision optical mirror support system. Summary of the invention

[0003] In order to solve the problems existing in the above-mentioned traditional two-force bar mechanism and reasonably utilize the advantages of the simple principle and compact structure of the two-force bar, while overcoming the defects of the traditional spherical pair and the disadvantages of heavy weight and complex process, the present invention provides a gapless flexible two-force bar mechanism based on the principle of a flexible mechanism, which can be easily fine-tuned and tightened at both ends, so as to realize a precision two-force bar mechanism with a small angular working range, good repeatability, easy installation and adjustment, lightweight and simple process.

[0004] The technical solution adopted by the present invention to solve its technical problem is:

[0005] A lightweight flexible two-force rod mechanism comprises a two-force slender rod, both ends of the two-force slender rod having a thin neck with a diameter smaller than that of the two-force slender rod, both ends of the two-force slender rod obtain a preset bending stiffness at the thin neck, thereby obtaining a two-degree-of-freedom rotation with flexibility within a preset rotation angle range, both ends of the two-force slender rod are provided with steel balls fastened to the thin neck, and the two ends of the two-force slender rod are respectively installed on the part to be installed by means of a pressure cap and the steel ball.

[0006] Furthermore, the diameter and length of the two-force slender rod and the diameter and length of the slender neck are determined by the tensile and compressive loads they bear.

[0007] Furthermore, the surface where the pressure cap cooperates with the steel ball is a concave cone surface.

[0008] Furthermore, the thin necks at both ends of the two-force slender rod are completely identical, and the steel balls at both ends of the two-force slender rod are completely identical.

[0009] Furthermore, both ends of the two-force slender rod are connected to the steel ball through threaded engagement, and the end of the two-force slender rod is provided with a flat end for facilitating the use of tools to tighten the thread.

[0010] Furthermore, the inner hole diameter of the pressure cap is slightly larger than the diameter of the two-force slender rod, and the length of the pressure cap completely covers the slender neck.

[0011] Furthermore, the light flexible two-force rod mechanism is used for precise support of the optical mirror and is installed between the optical mirror and the axial support floating frame.

[0012] Furthermore, the pressure cap includes an upper pressure cap and a lower pressure cap, both of which are sleeved on the two-force slender rod between the two steel balls; during assembly: a transition steel ball seat is fixedly installed on the back of the optical mirror, the upper steel ball of the light two-force rod mechanism is installed into the transition steel ball seat, the upper steel ball is pressed with the upper pressure cap and the upper pressure cap is locked; a flat pressure cap is installed at the bottom of the longitudinal hole of the supporting floating frame and locked, the steel ball at the lower end of the light two-force rod mechanism is placed in the longitudinal hole, the lower steel ball is pressed with the lower pressure cap and the lower pressure cap is locked.

[0013] Furthermore, by adjusting the pressure cap, the assembly stress can be released, and the verticality between the light flexible two-force rod mechanism and the optical mirror and the axial support floating plate can be adjusted.

[0014] Furthermore, when multiple sets of the light flexible two-force rod mechanism are used for precision support of the same optical mirror at the same time, their lengths are the same, and the length error of the light flexible two-force rod mechanism and the distance error between the optical mirror and the axial support floating frame are adjusted by the lower end pressure cap. Compared with the prior art, the beneficial effects of the present invention are:

[0015] The present invention realizes a lightweight, flexible, gapless two-force rod mechanism, and its strength and the compliance of the flexible hinge can be designed according to actual work needs. It has the advantages of simple structure, symmetry and compactness, low cost, easy installation, and easy adjustment, and is particularly suitable for the field of optical mirror precision support. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the schematic diagram of the traditional optical mirror axial support mechanism;

[0017] Figure 2 It is a diagram of the assembly of a light flexible two-force rod mechanism;

[0018] Figure 3 It is the assembly drawing of a light flexible two-force rod mechanism used for axial support of optical mirrors;

[0019] Figure 4 It is a 3D exploded diagram of a lightweight flexible two-force rod mechanism used for axial support of optical mirrors.

[0020] Markings in the figure: 1- two-force slender rod, 2- upper steel ball, 3- lower steel ball, 4- upper inner conical pressure cap, 5- lower inner conical pressure cap, 6- flat pressure cap, 7- first set screw, 8- second set screw, 9- transition steel ball seat, 10- third set screw, 11- screw, 12- Invar pad, 13- optical mirror, 14- axial support floating frame, 15- frame, 16- lever, 17- spherical pair, 18- two-force rod, 19- upper flat mouth, 20- upper thin neck, 21- lower thin neck, 22- lower flat mouth. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0022] A slender rod with an appropriate length-to-thickness ratio can be used as a force transmission rod of a two-force rod that transmits tension and pressure. Based on the principle of the two-force rod, appropriate Hooke hinges are set at both ends of the rod—with two rotational degrees of freedom—to realize a two-force rod mechanism. Based on the understanding of the principle of precision support of optical mirrors, that is, the axial support point of the optical mirror only needs to have a small rotation range, see Figure 2 At both ends of the two-force slender rod 1, the slender rod is manufactured with completely identical thin necks of appropriate length with a relatively thin diameter, namely, an upper thin neck 20 and a lower thin neck 21, so that both ends of the two-force slender rod 1 obtain a smaller bending stiffness at the thin necks, thereby obtaining a two-degree-of-freedom rotation with good flexibility in a small angle range, that is, a Hooke's hinge with equivalent function is realized. This two-force rod mechanism based on a slender rod and realized by setting thin necks at both ends has the characteristics and advantages of simple structure, light weight, small angle, and gapless force transmission.

[0023] The following requirements should be met when designing this light two-force rod. First, the diameter of the slender rod itself and the diameter of its neck should be designed according to the size of the tensile and compressive loads to ensure that it has sufficient strength; the diameter and length of the two-force rod neck should also be set according to the size of the bending moment caused by the slight rotation of the two-force rod neck that the supported optical mirror is allowed to bear at the support point; finally, the length and diameter of the neck should be checked according to the size of the compressive load to avoid instability.

[0024] The specific implementation process of the light flexible two-force rod mechanism of the present invention is introduced below.

[0025] See also Figure 2 In order to facilitate the subsequent use and simplify the processing, installation and adjustment process, the two ends of the two-force slender rod 1 are provided with completely identical external threads, and a completely identical steel ball, namely, an upper steel ball 2 and a lower steel ball 3, is respectively fastened through threaded connection. In order to facilitate the use of a wrench to tighten the threads, completely identical flat ends, namely, an upper flat end 19 and a lower flat end 22, are provided at the ends of the two-force slender rod 1. In this way, a lightweight two-force rod structural component with completely identical and symmetrical ends ready for installation and use is formed.

[0026] See also Figure 2 and Figure 3 , the optical mirror surface 13 is generally provided with a number of metal transition pieces on its non-working back side by gluing, which are often made of invar material and are generally called invar pads 12. Threads are provided on the invar pads 12 to facilitate the connection of the support mechanism. The transition steel ball seat 9 is connected and fastened on the invar pads 12 by screws 11. The upper steel ball 2 at one end of the light two-force rod structural assembly is installed into the transition steel ball seat 9, and the upper inner conical pressure cap 4 is used to press the upper steel ball 2 through threads, and the third set screw 10 is used to lock it. The flat pressure cap 6 is screwed into the threaded hole of the axial support floating frame 14, and the second set screw 8 is used to lock it. Then the lower steel ball 3 at the lower end of the light two-force rod structural assembly is placed in the threaded hole of the axial support floating frame 14, and the lower steel ball 3 is pressed by tightening the lower inner conical pressure cap 5, and the first set screw 7 is used to lock it. In this way, the assembly of the light flexible two-force rod mechanism of the present invention in the optical mirror axial support system is completed.

[0027] It is necessary to add that:

[0028] The upper inner conical pressing cap 4 and the lower inner conical pressing cap 5 are designed with concave cone surfaces, which are convenient for free matching and locking with the upper steel ball 2 and the lower steel ball 3, which makes it easy to adjust the verticality of the two-force slender rod 1 relative to the optical mirror 13 and the axial support floating frame 14.

[0029] The inner hole diameters of the upper inner conical pressing cap 4 and the lower inner conical pressing cap 5 are slightly larger than the diameter of the two-force slender rod 1, and their lengths completely cover the thin neck, so that the two-force slender rod 1 has bending space at the thin neck and can limit excessive bending, thereby avoiding damage to the thin neck. In addition, there is space for adjusting the verticality of the two-force slender rod 1 relative to the optical mirror 13 and the axial support floating frame 14.

[0030] When multiple sets of the light-weight flexible two-force rod mechanism assembly of the present invention are used together in the same optical mirror axial support, they can be designed to have the same length. When in use and assembly, the lower inner conical pressure cap 5 and the flat pressure cap 6 can be used to adjust the length error of the two-force rod mechanism assembly and the distance error between the optical mirror 13 and the axial support floating plate 14.

[0031] The installation and adjustment process of the present invention is further described below:

[0032] See also Figure 2 and Figure 3 During installation, first remove one of the upper steel ball 2 or the lower steel ball 3, put the upper inner conical pressure cap 4 and the lower inner conical pressure cap 5 on the two-force slender rod 1 in the correct direction, and then retighten the removed upper steel ball 2 or the lower steel ball 3 and the two-force slender rod 1.

[0033] After the optical mirror axial support system is completely installed, the upper inner conical pressing cap 4 and the lower inner conical pressing cap 5 can be slightly loosened to release the assembly stress, and the verticality between the two-force rod assembly and the optical mirror 13 and the axial support floating plate 14 can be adjusted.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement and improvement made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A light flexible two-force rod mechanism, characterized in that: It comprises a two-force slender rod, both ends of which have thin necks with diameters smaller than that of the two-force slender rod, and both ends of the two-force slender rod obtain preset bending stiffness at the thin necks, thereby obtaining a two-degree-of-freedom rotation with flexibility within a preset rotation angle range, and both ends of the two-force slender rod are provided with steel balls fastened to the thin necks, and the two ends of the two-force slender rod are respectively installed on the parts to be installed by means of a pressure cap and the steel ball.

2. A light flexible two-force rod mechanism according to claim 1, characterized in that: The diameter and length of the two-force slender rod and the diameter and length of the thin neck are determined by the tensile and compressive loads they bear.

3. A light flexible two-force rod mechanism according to claim 1, characterized in that: The surface where the pressure cap and the steel ball cooperate is a concave cone surface.

4. A light flexible two-force rod mechanism according to claim 1, characterized in that: The thin necks at both ends of the two-force slender rod are completely identical, and the steel balls at both ends of the two-force slender rod are completely identical.

5. A light flexible two-force rod mechanism according to claim 1, characterized in that: The two ends of the two-force slender rod are connected to the steel ball through threaded cooperation, and the end of the two-force slender rod is provided with a flat mouth for tightening the thread with a tool.

6. A light flexible two-force rod mechanism according to claim 1, characterized in that: The inner hole diameter of the pressure cap is slightly larger than the diameter of the two-force slender rod, and the length of the pressure cap completely covers the slender neck.

7. A light flexible two-force rod mechanism according to claim 1, characterized in that: The light flexible two-force rod mechanism is used for precise support of the optical mirror surface and is installed between the optical mirror surface and the axial support floating frame.

8. A light flexible two-force rod mechanism according to claim 7, characterized in that: The pressure cap includes an upper pressure cap and a lower pressure cap, both of which are sleeved on the two-force slender rod between the two steel balls; during assembly: a transition steel ball seat is fixedly installed on the back of the optical mirror, the upper steel ball of the light two-force rod mechanism is installed into the transition steel ball seat, the upper steel ball is pressed tightly with the upper pressure cap and the upper pressure cap is locked; a flat pressure cap is installed and locked at the bottom of the longitudinal hole of the supporting floating frame, the steel ball at the lower end of the light two-force rod mechanism is placed in the longitudinal hole, the lower steel ball is pressed tightly with the lower pressure cap and the lower pressure cap is locked.

9. A light flexible two-force rod mechanism according to claim 8, characterized in that: By adjusting the pressure cap, the assembly stress can be released, and the verticality between the light flexible two-force rod mechanism and the optical mirror and the axial support floating plate can be adjusted.

10. A light flexible two-force rod mechanism according to claim 8, characterized in that: When multiple sets of the light flexible two-force rod mechanism are used simultaneously for the precision support of the same optical mirror, they have the same length, and the length error of the light flexible two-force rod mechanism and the distance error between the optical mirror and the axial support floating frame are adjusted by the lower end pressure cap.

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