A prism switching device

Abstract

The present invention relates to a prism switching device, comprising a prism wheel, a central axis, a transmission system, and a mechanical positioning and locking device. The prism wheel is disc-shaped and rotates about the central axis. Multiple holes for mounting prisms are evenly distributed on the disc portion of the prism wheel. The top of the central axis is connected to the mechanical positioning and locking device. The transmission system includes a motor, a pinion, and a gear. The motor shaft of the motor is connected to the pinion, which has a notch on the outside. The pinion meshes with the gear, which is mounted on the bottom of the prism wheel and directly connected to the prism wheel. The mechanical positioning and locking device includes a swing arm, a spring, and a locking edge. The swing arm is disposed outside the prism wheel and has a locking edge on the top. The spring is connected to the other end of the swing arm. This device makes the prism switching process smoother, the prisms are accurately and repeatedly positioned, and the reliability of the system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical engineering, and in particular to a prism switching device. Background Art

[0002] Prism switching devices play an important role in astronomical optical instruments, imaging equipment, and astronomical observation. Accurate prism switching and positioning are crucial for precise spectral separation and analysis across different spectral ranges. However, existing prism switching devices often face numerous challenges in high-precision applications.

[0003] Traditional prism switching typically utilizes a coaxial drive, where a motor is mounted directly on the prism wheel, driving the motor to switch the prisms. A code disk (encoder) is mounted on the motor's rotating shaft to detect the rotation angle and provide positioning feedback. This closed-loop approach enables angle and position control and is very common in systems requiring high-precision motion control. However, while this design can provide high-precision control in certain applications, it also has significant limitations. First, the feedback code disk is large. Especially in miniaturized designs, its size and weight can consume valuable space within the system, limiting its compactness. Furthermore, the high cost of high-precision code disks increases overall system manufacturing costs. Second, traditional coaxial drive approaches can suffer from overperformance. For most applications, positioning accuracy of only a few dozen to thirty arc seconds is sufficient, but high-precision code disk designs often exceed this requirement, increasing system complexity, cost, and maintenance. In addition to coaxial drive, another common prism switching approach utilizes direct meshing of a large and small gear. The motor is mounted on the side of the eccentric axis and drives the large gear by rotating the small gear, thereby achieving the switching of the prism wheel. However, this design has a significant problem, namely the tooth side clearance. This clearance causes errors in the transmission system, making the positioning of the prism wheel less accurate after switching. Even if the motor control accuracy is very high, the clearance between the gears will still introduce errors, resulting in unstable switching position of the prism and unable to meet the requirements of high-precision applications. In addition, in traditional gear transmission systems, tooth clearance and processing errors are inevitably present, resulting in insufficient positioning accuracy of the prism after switching. After multiple switching, the system's repeatability is difficult to guarantee, and the prism may not be able to return to its original precise position. This is a significant drawback for systems that require long-term stable operation. Coupled with the friction and wear problems between the gears, the reliability and life of the system are also affected. Therefore, a prism switching device is needed that can ensure high precision while having high reliability and stability. Summary of the Invention

[0004] In order to solve the existing technical problems, the present invention provides a high-precision prism switching device for spectral separation.

[0005] The specific contents of the present invention are as follows: A prism switching device includes a prism wheel, a central axis, a transmission system, and a mechanical positioning and locking device; the prism wheel is disc-shaped, and the prism wheel rotates around the central axis, and a plurality of holes for installing prisms are evenly distributed on the disc part of the prism wheel; the top of the central axis is connected to the mechanical positioning and locking device; the transmission system includes a motor, a pinion and a large gear, the motor shaft of the motor is connected to the pinion, the outer side of the pinion is provided with a notch, the pinion is meshed with the large gear, and the large gear is installed at the bottom of the prism wheel and directly connected to the prism wheel; the mechanical positioning and locking device includes a swing arm, a spring and a locking edge, the swing arm is arranged on the outside of the prism wheel, and a locking edge is provided on the top, and the spring is connected to the other end of the swing arm. When the prism wheel rotates, the locking edge disengages from the prism wheel under the movement of the swing arm. When the prism wheel rotates to the next prism position, the swing arm moves under the action of the spring, and the locking edge locks the prism wheel.

[0006] Furthermore, the small gear switches to the notch when it rotates one circle. The notch is crescent-shaped and has a symmetrical arc design. The curvature radius of the curved surface at the notch is larger than the curvature radius of the tooth top circle of the large gear. When the notch of the small gear is aligned with the large gear, the small gear disengages from the large gear at the notch, and the large gear enters a free state, that is, the large gear can rely on inertia and the action of the spring and the swing arm to perform slight free rotation.

[0007] Furthermore, the transmission ratio of the transmission system satisfies that when the small gear rotates one circle, the large gear drives the prism wheel to complete the switching of one prism.

[0008] Furthermore, several groups of small bearings located outside the prism are provided on the edge of the prism wheel, each group including two small bearings. The space formed by the two small bearings and the edge of the prism wheel can position and lock the locking edge, and the locking edge can be disengaged from the space when the prism wheel rotates.

[0009] Furthermore, the edge of the swing arm is extended from the contact point between the locking edge and the small bearing, and the surface of the locking edge is a plane or a curved surface.

[0010] Furthermore, the locking edge includes two surfaces, and the angle between the two surfaces is between 40 and 50 degrees. When the prism wheel needs to rotate in both directions, the two surfaces of the locking edge are designed to be a symmetrical inclined surface structure; when only unidirectional rotation is required, an asymmetric structure with one side being a plane and the other side being an inclined surface is adopted.

[0011] The notched pinion of the present invention enables the transmission system to have an intermittent disengagement mechanism, and the design of the mechanical positioning and locking device enables the device to be accurately locked when the prism wheel rotates, ensuring the high precision of the system in spectral separation applications and having good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The specific embodiments of the present invention will be further explained below with reference to the accompanying drawings.

[0013] Figure 1 This is a front view of the prism switching device of the present invention.

[0014] Figure 2 It is a top view of the prism switching device of the present invention. DETAILED DESCRIPTION

[0015] Combine Figure 1 and Figure 2 The high-precision prism switching device for spectral separation of the present invention mainly includes three parts: a prism wheel and a central axis, a transmission system, and a mechanical positioning and locking device.

[0016] In this embodiment, the prism wheel 1 is disc-shaped, with a cylindrical center section. A central axis 5 is fixedly positioned within the cylinder, and the top of the central axis 5 is connected to a mechanical positioning and locking mechanism. The prism wheel 1 rotates around the central axis 5. Multiple holes are evenly distributed throughout the disc portion of the prism wheel 1 for mounting the prisms 2. This ensures that the prisms 2 are precisely aligned with the optical path during rotation, meeting spectral separation requirements. In this embodiment, four prisms are installed, evenly distributed along the edge of the prism wheel 1.

[0017] The transmission system includes a motor 4, a small gear 9, and a large gear 10. The motor 4 is the core driving part of the transmission system, responsible for providing power to drive the prism wheel 1 to rotate. The present invention can use a DC motor or a stepper motor according to the application requirements of the system.

[0018] The motor 4 is directly connected to the pinion 9 through its motor shaft 3 to ensure power transmission. The pinion 9 is driven to rotate by the motor 4, and its external gear part is engaged with the large gear 10. In the design of the pinion 9, special consideration is given to the existence of a notch. This notch design allows the pinion 9 to temporarily disengage from the large gear 10 when it rotates to a specific angle. The pinion 9 can switch to the notch state exactly every time it rotates one circle. It ensures that it can reduce excessive impact on the large gear 10 during the transmission process during the disengagement process, and also allows the system to automatically perform short-term adjustments and buffers when the prism is switched to ensure smooth switching.

[0019] The notch of the small gear 9 is crescent-shaped and symmetrically arc-shaped, and its curvature radius is greater than the curvature radius of the tooth top circle of the large gear 10. When the notch of the small gear 9 is aligned with the large gear 10, the large gear 10 is disengaged from the engagement with the small gear 9 and enters a state of free rotation, that is, the large gear 10 can rely on inertia and the action of the spring and the swing arm to perform slight free rotation.

[0020] The large gear 10 is mounted on the bottom of the prism wheel 1 and is directly connected to the prism wheel 1, responsible for driving the prism wheel 1 to rotate. The large gear 10 transmits the power of the motor 4 to the prism wheel 1 by meshing with the small gear 9, thereby achieving the switching of the prism.

[0021] When the notch in the small gear 9 aligns with the large gear 10, the large gear 10 enters a free state. At this point, the large gear 10, relying on inertia and the action of the spring 8 and the swing arm 7 within the system, rotates slightly freely. This free rotation allows the large gear 10 to be fine-tuned during prism switching, ensuring that the prism wheel 1 smoothly switches to the next prism position. Finally, the large gear 10 is securely locked by the detent edges 11 and 12, ensuring precise positioning after prism switching.

[0022] The design of the transmission ratio of the transmission system needs to take into account the rotation angle requirements of the prism wheel 1, as well as the number, size, shape, etc. of the prisms, and is adjusted according to specific application requirements to ensure that the prisms can meet the spectral separation requirements after switching. In this embodiment, the number of prisms N of the prism switching device is p The number of teeth Z of the large gear 10 and the small gear 9 in the transmission system l 、Z s The following design relationship exists: N is evenly distributed on the prism wheel 1 p prisms, each time the prism is switched, the angle of rotation of the prism wheel 1 is: θ=360° / N p To ensure the precise switching of the prism in the optical path, the angle of rotation of the large gear 10 is also θ. The small gear 9 drives the large gear 10 through the motor 4. The transmission ratio between the two is defined as: R=Z l / Z s Each time the small gear 9 rotates a full circle (360°), the large gear 10 rotates by an angle of: θ l =360° / R=(360°•Z s ) / Z l In order to achieve the requirement that the prism wheel 1 completes a prism switch every time the small gear 9 rotates a full circle, the rotation angle of the large gear 10 must meet the following requirements: θ l =360° / N p From this we can get: (360°•Z s ) / Z l =360° / N pAfter sorting, we get the relationship between the number of teeth: Z l =N p •Z s Among them, the number of teeth of the pinion 9 is Z s This is the actual number of teeth, not the equivalent number of teeth that includes gaps.

[0023] The calculated transmission ratio ensures that the rotational relationship between the small gear 9 and the large gear 10 can accurately control the switching position of the prism. Through the rational transmission ratio design, the large gear 10 can accurately drive the prism wheel 1 to complete the switching of one prism for each rotation of the small gear 9, so that the system can maintain consistent high precision under different operating conditions.

[0024] The mechanical positioning and locking mechanism includes a swing arm 7, a spring 8, and a retaining edge. Two small bearings are located outside the edge of the prism wheel 1, corresponding to the position behind each filter. Four sets of small bearings are provided, with two small bearings forming a set. The space formed by the two small bearings 6 and the edge of the prism wheel 1 allows the retaining edge to be positioned and locked. The retaining edge can be released from this space when the prism wheel 1 rotates. The small bearings 6, swing arm 7, and retaining edge cooperate to ensure prism switching accuracy and spectral separation performance.

[0025] Spring 8 plays a crucial role in the mechanical positioning and locking mechanism. It applies elastic force to swing arm 7, ensuring that it maintains close contact with the small bearing 6 on the outside of prism wheel 1. In the actual design, one end of spring 8 is connected to the swing arm, and the other end is fixed to the base of the device.

[0026] The swing arm 7, through spring force, maintains close contact with the small bearing 6 on the outside of the prism wheel 1, providing both positioning and support. The design of the swing arm 7 has been meticulously tuned to ensure stable support for the prism wheel 1 when appropriate force is applied, while also ensuring flexible response to system demands during prism switching. The combination of the swing arm 7 and spring 8 allows the entire system to rapidly adjust during prism switching and precisely position the prism at the desired location after the switch is complete.

[0027] The locking edge is crucial for achieving final locking of the prism. In this embodiment, two locking edges 11 and 12 are provided at one end of the swing arm 7. The surface design of the locking edges 11 and 12 can be flat or curved to suit different system requirements. The angle between the two surfaces is typically set between 40 and 50 degrees. In this design, the sharper the angle, the better, as long as the system does not self-lock.

[0028] The design of the retaining edges 11 and 12 is flexible and diverse: if the prism wheel 1 requires bidirectional rotation, the two inclined surfaces can be designed as a symmetrical structure; if only unidirectional rotation is required, an asymmetrical design with one flat surface and the other inclined surface can be adopted. This design not only ensures smooth prism switching but also prevents reverse rotation errors, further improving system reliability.

[0029] In this embodiment, the locking edges are two symmetrical inclined planes with an included angle of 45°. The ends of the two locking edges are parallel to the edge of the swing arm, so that the cross-section there is an isosceles trapezoid, which can realize clockwise or counterclockwise switching of the prism to meet various usage requirements.

[0030] The mechanical positioning and locking mechanism operates as follows: When prism wheel 1 completes the switching of prisms 2 under the action of the transmission system, the mechanical positioning and locking mechanism finally locks prism 2 by engaging retaining edges 11 and 12 with small bearing 6. Regardless of any slight mechanical play in the system, retaining edges 11 and 12, driven by spring force and swing arm 7, automatically adjust and tightly fit prism wheel 1, ensuring the precise positioning of prism 2. This locking mechanism ensures that prism 2 remains stable in its predetermined position after each prism switching, preventing any possible movement and ensuring high precision in spectral separation applications.

[0031] The specific operations of this embodiment are as follows:

[0032] Take switching the prism clockwise as an example:

[0033] In this embodiment, four prisms (i.e., N p =4), the number of teeth of the pinion 9 is selected as 10 teeth (ie Z s =10) According to Z l =N p •Z s Relationship, the number of teeth Z of the large gear 10 l Under this design, every time the small gear 9 rotates a full circle, the large gear 10 rotates 90° to complete a prism switch.

[0034] Before prism wheel 1 begins to rotate, with the prism positioned within the optical path, swing arm 7, leveraging the force of spring 8, presses locking edges 11 and 12 firmly against two small bearings 6 on the exterior of prism wheel 1, ensuring that prism wheel 1 remains stable in its current prism position. At this point, the surfaces of locking edges 11 and 12 are in close contact with the surfaces of small bearings 6, firmly locking prism wheel 1.

[0035] When the operation starts, the motor 4 is started by the control system. After the motor 4 receives the rotation instruction, the motor shaft 3 starts to rotate counterclockwise, and drives the pinion 9 directly connected to it to rotate counterclockwise through the motor shaft 3.

[0036] As pinion 9 rotates, its teeth mesh with those of gear 10, transmitting power to gear 10 and further to prism wheel 1, which is mounted on it. Due to the transmission ratio, every time pinion 9 rotates one full turn, gear 10 drives prism wheel 1 90 degrees. When pinion 9 completes one full turn, motor 4 stops.

[0037] During the initial rotation, the detent edges 11 and 12 gradually disengage from their contact point with the small bearing 6, and the swing arm 7 moves slightly outward, allowing the prism wheel 1 to rotate smoothly. At this point, while the detent edges 11 and 12 are no longer in direct contact, they maintain a close distance, ready to relock when the prism wheel 1 reaches the next prism position. The prism wheel 1 begins to rotate clockwise, pulling the upper prism out of the optical path and bringing the next prism into the optical path. During the prism wheel's rotation, due to the notch in the pinion 9, the two gears temporarily disengage when the notch aligns with the large gear 10, allowing the prism wheel 1 to enter a free state. In this state, the prism wheel 1 continues to rotate slightly due to inertia. Once the prism wheel 1 reaches the next prism position, the swing arm 7, driven by the spring force, quickly presses the detent edges 11 and 12 against the small bearing 6. The detent edges 11 and 12 gradually approach and eventually re-contact the inner surface of the small bearing 6, stopping the prism wheel 1 and stabilizing it at the new prism position. The surface design of the locking edges 11 and 12 ensures that even if there is a slight mechanical gap, slight adjustments can be made automatically to achieve precise locking of the prism wheel 1 .

[0038] When the locking edges 11 and 12 completely lock the prism wheel 1, the swing arm 7 remains fixed under the action of the spring force. At this time, the rotation of the prism wheel 1 stops and the system enters a stable state. At this time, the operator can perform spectral separation or other optical operations as needed.

[0039] If multiple prisms need to be switched continuously, the operator can issue rotation commands continuously through the control system, and Prism Wheel 1 will rotate clockwise to switch each prism in sequence. After each switch is completed, the system will automatically lock Prism Wheel 1 and continue the next operation after the lock is confirmed, ensuring the efficiency and accuracy of the entire process.

[0040] The prism switching device of the present application realizes the precise switching and stable positioning of the prism through mechanical transmission and positioning devices, ensuring the accuracy of spectral separation and the efficiency of the system. Through the design of the notched pinion and the locking edge with a certain tilt angle, the notched pinion enables the transmission system to have an intermittent disengagement mechanism, and the locking edge design can support bidirectional rotation or unidirectional locking according to needs, so that the device can adapt to different operating scenarios. The prism switching device of the present application can be used to switch various optical elements such as prisms, gratings, plane mirrors, lenses, filters, etc.

[0041] In the above description, many specific details are set forth in order to fully understand the present invention. However, the above description is only a preferred embodiment of the present invention. The present invention can be implemented in many other ways different from those described herein, so the present invention is not limited to the specific implementation disclosed above. At the same time, any person skilled in the art can make many possible changes and modifications to the technical solution of the present invention using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A prism switching device, characterized in that: The invention comprises a prism wheel, a central axis, a transmission system, and a mechanical positioning and locking device; the prism wheel is in the shape of a disk and can be installed with multiple prisms. The prism wheel rotates around the central axis, and a plurality of holes for installing prisms are evenly distributed on the disk part of the prism wheel; the top of the central axis is connected to the mechanical positioning and locking device; the transmission system comprises a motor, a small gear and a large gear, the motor shaft of the motor is connected to the small gear, the outer side of the small gear is provided with a notch, the small gear is meshed with the large gear, and the large gear is installed at the bottom of the prism wheel and directly connected to the prism wheel; the mechanical positioning and locking device comprises a swing arm, a spring and a locking edge, the swing arm is arranged on the outside of the prism wheel, the top is provided with a locking edge, and the spring is connected to the other end of the swing arm. When the prism wheel rotates, the locking edge is separated from the prism wheel under the movement of the swing arm. When the prism wheel rotates to the next prism position, the swing arm moves under the action of the spring, and the locking edge locks the prism wheel.

2. The prism switching device according to claim 1, wherein: When the small gear rotates one circle, it switches to the notch. The notch is crescent-shaped and has a symmetrical arc design. The curvature radius of the curved surface at the notch is larger than the curvature radius of the tooth top circle of the large gear. When the notch of the small gear is aligned with the large gear, the small gear disengages from the large gear at the notch, and the large gear enters a free state, that is, the large gear can rely on inertia, springs, and swing arms to rotate slightly freely.

3. The prism switching device according to claim 2, wherein: The transmission ratio of the transmission system satisfies that the large gear drives the prism wheel to complete the switching of one prism every time the small gear rotates one circle.

4. The prism switching device according to claim 1, wherein: Several groups of small bearings are provided on the edge of the prism wheel, each group including two small bearings. The space formed by the two small bearings and the edge of the prism wheel can position and lock the locking edge, and the locking edge can be separated from the space when the prism wheel rotates.

5. The prism switching device according to claim 4, wherein: The edge of the swing arm is extended from the contact point between the locking edge and the small bearing, and the surface of the locking edge is a plane or a curved surface.

6. The prism switching device according to claim 5, wherein: The locking edge includes two surfaces, and the angle between the two surfaces is between 40 and 50 degrees. When the prism wheel needs to rotate in both directions, the two surfaces of the locking edge are designed as a symmetrical inclined surface structure; when only unidirectional rotation is required, an asymmetric structure with one side being a flat surface and the other being an inclined surface is adopted.

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