Handheld device and method for tomographic photoacoustic imaging of object

Abstract

The invention discloses a handheld device and method for tomography photoacoustic imaging of an object. The handheld device comprises a photoacoustic imager body. An angle-adjustable rotating mechanism is arranged at the bottom of the photoacoustic imager body, and a direction-adjustable rotating mechanism is arranged at the bottom of the rotating mechanism; through cooperative arrangement of the rotating mechanism and the rotating mechanism, the device has the advantage of adjusting the angle and the direction in the tomography process of an object, not only can people conveniently carry out handheld operation, but also the posture and the direction of the angle can be continuously kept in the using process, the stability in the continuous tomography process is guaranteed, and the practicability is high. Angle adjustment is achieved through cooperation among the supporting assembly, the rotating assembly and the positioning assembly in the rotating mechanism, locking operation can be achieved after adjustment, direction adjustment is achieved through cooperation among the connecting assembly, the limiting assembly and the elastic assembly in the rotating mechanism, meanwhile, direction locking can be achieved after adjustment, and the use requirements of people are met.

Description

Technical Field

[0001] The present invention relates to the field of tomography technology, and particularly relates to a handheld device and method for tomographic photoacoustic imaging of an object. Background Art

[0002] Photoacoustic imaging is a new non-invasive and non-ionizing biomedical imaging method developed in recent years. When a pulsed laser irradiates (in thermoacoustic imaging, it specifically refers to irradiating with a pulsed laser of radio frequency) biological tissue, ultrasonic signals will be generated in the light absorption region of the tissue. We call the ultrasonic signals generated by light excitation photoacoustic signals. The photoacoustic signals generated by biological tissue carry the light absorption characteristic information of the tissue. By detecting the photoacoustic signals, an image of the light absorption distribution in the tissue can be reconstructed. Photoacoustic imaging combines the advantages of high selectivity in pure optical tissue imaging and deep penetration in pure ultrasonic tissue imaging, and can obtain high-resolution and high-contrast tissue images.

[0003] In the prior art, in order to improve the convenience of using photoacoustic imaging, the original equipment is integrated and scaled down to a handheld form for use. However, the existing handheld device is directly installed at the bottom of a photoacoustic imaging instrument. During actual use, it needs to be adjusted according to the rotation of the hand, and the posture and angle cannot be continuously maintained during the adjustment process, which reduces the effect of tomographic imaging of the object. Summary of the Invention

[0004] The purpose of the present invention is to provide a handheld device and method for tomographic photoacoustic imaging of an object, which has the advantages of being able to adjust the angle and direction according to needs during the handheld process, and can be directly handheld after adjustment and continuously maintain the angle and direction during the tomographic imaging process, facilitating people's use, so as to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions: A handheld device and method for tomographic photoacoustic imaging of an object, including a photoacoustic imaging instrument body; An adjustable-angle rotating mechanism is provided at the bottom of the photoacoustic imaging instrument body, an adjustable-direction rotating mechanism is provided at the bottom of the rotating mechanism, and a handheld holding mechanism is provided at the bottom of the rotating mechanism; The rotating mechanism includes a support component, a rotating component and a positioning component. The support component is provided at the bottom of the photoacoustic imaging instrument body, the rotating component is provided inside the support component, and the positioning component is provided outside the support component; The rotating mechanism includes a connecting component, a limiting component and an elastic component. The connecting component is provided at the bottom of the support component, the limiting component is provided inside the connecting component, and the elastic component is provided at the bottom of the limiting component; The holding mechanism includes a first bearing component and a second bearing component. The first bearing component is disposed at the bottom of the elastic component, and the second bearing component is disposed at the bottom of the first bearing component.

[0006] Exemplarily, the support component includes a support base fixedly installed at the bottom of the photoacoustic imager body. A bracket is rotatably connected to the outside of the support base, and an arc-shaped toothed plate is fixedly installed at the bottom of the support base.

[0007] Exemplarily, the rotating component includes a shaft rod rotatably connected through the inside of the bracket. A first gear is fixedly installed on the outside of the shaft rod, and the first gear meshes with the arc-shaped toothed plate.

[0008] Exemplarily, the positioning component includes a first spring and a first telescopic rod. Both the first spring and the first telescopic rod are fixedly installed on one side of the bracket. The first spring is located outside the first telescopic rod. One end of the first spring and the first telescopic rod is fixedly installed with a connecting sleeve. A first toothed ring is fixedly installed on the inner side wall of the connecting sleeve. A second toothed ring meshes with the inside of the first toothed ring, and the second toothed ring is fixedly installed on the outside of the shaft rod.

[0009] Exemplarily, the connecting component includes a mounting seat fixedly installed at the bottom of the bracket, and a connecting pipe is fixedly installed at the bottom of the mounting seat.

[0010] Exemplarily, the limiting component includes a connecting rod fixedly installed at the top of the inner cavity of the connecting pipe. A second gear is fixedly installed at the bottom end of the connecting rod, and a circular plate is rotatably connected to the bottom of the second gear.

[0011] Exemplarily, the elastic component includes a third toothed ring meshing on the outside of the second gear. A sleeve is fixedly installed on the outside of the third toothed ring. A second spring and a second telescopic rod are fixedly installed at the bottom of the inner cavity of the sleeve. The second spring is located outside the second telescopic rod. The top ends of the second spring and the second telescopic rod are fixed to the bottom of the circular plate.

[0012] Exemplarily, the first bearing component includes a vertical rod fixedly installed at the bottom end of the sleeve. A first internal thread groove is formed at the bottom of the vertical rod. A first external thread joint is threadedly connected inside the first internal thread groove. A lengthening rod is fixedly installed at the bottom end of the first external thread joint, and a second internal thread groove is formed at the bottom of the lengthening rod.

[0013] Exemplarily, the second bearing component includes a second external thread joint threadedly connected inside the second internal thread groove. A holding rod is fixedly installed at the bottom end of the second external thread joint, and a rubber sleeve is fixedly installed on the outside of the holding rod; One end of the photoacoustic imager body is engaged with an outer cover, and a sponge pad is fixedly installed at one end of the inner cavity of the outer cover.

[0014] A handheld method for photoacoustic imaging includes the following steps: S1. Handheld operation: First, thread the extension rod to the vertical rod through the first external thread joint to increase the usage length, and then thread the holding rod to the extension rod through the second external thread joint for auxiliary holding. Drive the photoacoustic imager body to the preset position for detection by holding the rubber sleeve position, and it can be adjusted according to requirements. S2. When adjusting the angle, press the connecting sleeve and compress the first spring and the first telescopic rod. At this time, the connecting sleeve drives the first gear ring to disengage from the meshing state of the second gear ring, and then rotate the shaft rod to drive the first gear to rotate. Drive the support seat and the photoacoustic imager body on the top to complete the angle rotation according to the meshing of the first gear and the arc-shaped tooth plate. S3. When adjusting the direction, directly pull down the connecting pipe. The connecting pipe drives the second gear to press down through the connecting rod, simultaneously compressing the second spring and the second telescopic rod, and the meshing state between the second gear and the third gear ring is disengaged. Directly rotate the mounting seat to the required angle and then release the downward pulling force. According to the reaction force of the second spring, the second gear and the third gear ring are meshed and locked.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. Through the combined setting of the rotation mechanism and the rotation mechanism, the present invention has the advantages of adjusting the angle and direction during the tomographic imaging process of an object. It not only facilitates people's handheld operation, but also can continuously maintain the angle posture and direction during use, ensuring the stability during the continuous tomography process. The angle adjustment and locking operation after adjustment are realized through the cooperation between the support component, the rotation component and the positioning component in the rotation mechanism. The direction adjustment is realized through the cooperation between the connection component, the limiting component and the elastic component in the rotation mechanism, and the direction can be locked after adjustment to meet people's usage requirements.

[0016] 2. Through the setting of the holding mechanism, it is convenient for the user to directly perform handheld operation during the photoacoustic imaging process of object tomography. It not only facilitates people's handheld operation, but also can hold different positions according to requirements for operation, and can be used with the preset length increased or reduced according to actual needs.

[0017] Other features and advantages of the present invention will be described in the following description, and, in part, will be obvious from the description, or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures pointed out in the description and the drawings. Description of the Drawings

[0018] Figure 1Schematic structural diagram of the present invention; Figure 2 Schematic structural diagram of the sponge pad of the present invention; Figure 3 Schematic structural diagram of the arc-shaped tooth plate of the present invention; Figure 4 For the present invention Figure 3 Partial enlarged structural diagram at position A in the present invention; Figure 5 Schematic structural diagram of the connecting rod of the present invention; Figure 6 Schematic structural diagram of the first external thread joint of the present invention.

[0019] In the figure: 1. Photoacoustic imager body; 2. Rotating mechanism; 21. Support base; 22. Arc-shaped tooth plate; 23. Bracket; 24. Shaft rod; 25. First gear; 26. First spring; 27. First telescopic rod; 28. Connecting sleeve; 29. First tooth ring; 210. Second tooth ring; 3. Rotating mechanism; 31. Mounting base; 32. Connecting pipe; 33. Connecting rod; 34. Second gear; 35. Circular plate; 36. Sleeve; 37. Third tooth ring; 38. Second spring; 39. Second telescopic rod; 4. Holding mechanism; 41. Vertical rod; 42. First internal thread groove; 43. First external thread joint; 44. Extension rod; 45. Second internal thread groove; 46. Second external thread joint; 47. Holding rod; 48. Rubber sleeve; 5. Outer cover; 6. Sponge pad. Detailed implementation manners

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0021] As Figure 1 and Figure 2 shown, the present invention provides a handheld device for tomographic photoacoustic imaging of an object, including a photoacoustic imager body 1. A rotatable angle rotating mechanism 2 is provided at the bottom of the photoacoustic imager body 1. An adjustable direction rotating mechanism 3 is provided at the bottom of the rotating mechanism 2. A hand-holdable holding mechanism 4 is provided at the bottom of the rotating mechanism 3.

[0022] The rotating mechanism 2 includes a support component, a rotating component and a positioning component. The support component is provided at the bottom of the photoacoustic imager body 1. The rotating component is provided inside the support component. The positioning component is provided outside the support component.

[0023] Angle adjustment operations can be performed during use through the cooperation among the support component, the rotation component, and the positioning component.

[0024] The rotation mechanism 3 includes a connection component, a limiting component, and an elastic component. The connection component is disposed at the bottom of the support component, the limiting component is disposed inside the connection component, and the elastic component is disposed at the bottom of the limiting component.

[0025] Direction adjustment operations can be performed during use through the cooperation among the connection component, the limiting component, and the elastic component.

[0026] The holding mechanism 4 includes a first bearing component and a second bearing component. The first bearing component is disposed at the bottom of the elastic component, and the second bearing component is disposed at the bottom of the first bearing component.

[0027] Through the cooperation between the first bearing component and the second bearing component, the required handheld length can be increased or decreased according to needs.

[0028] As Figure 3 shown, the support component includes a support base 21. The support base 21 is fixedly installed at the bottom of the photoacoustic imager body 1. A bracket 23 is rotatably connected to the outside of the support base 21. An arc-shaped toothed plate 22 is fixedly installed at the bottom of the support base 21, which performs a support operation to assist the lower components in performing angle adjustment operations.

[0029] As Figure 3 shown, the rotation component includes a shaft rod 24. The shaft rod 24 is rotatably connected through the inside of the bracket 23. A first gear 25 is fixedly installed on the outside of the shaft rod 24. The first gear 25 meshes with the arc-shaped toothed plate 22, which is convenient for realizing angle adjustment operations by means of rotation and meshing during adjustment, and the operation is simple and convenient.

[0030] As Figure 4 shown, the positioning component includes a first spring 26 and a first telescopic rod 27. Both the first spring 26 and the first telescopic rod 27 are fixedly installed on one side of the bracket 23. The first spring 26 is located outside the first telescopic rod 27. A connecting sleeve 28 is fixedly installed at one end of the first spring 26 and the first telescopic rod 27. A first toothed ring 29 is fixedly installed on the inner side wall of the connecting sleeve 28. A second toothed ring 210 meshes with the inside of the first toothed ring 29. The second toothed ring 210 is fixedly installed on the outside of the shaft rod 24. Locking operations after adjustment can be realized based on elasticity and the meshing between teeth. At the same time, the locking operation can also be released under pressing operations.

[0031] When performing the angle adjustment operation, first manually press the connecting sleeve 28, which will drive the first gear ring 29 to disengage from the second gear ring 210. At this time, the first spring 26 and the first telescopic rod 27 will be compressed. Then continue to press and manually rotate the shaft rod 24 to drive the first gear 25 to rotate. Due to the meshing connection between the first gear 25 and the arc-shaped tooth plate 22, the support base 21 and the photoacoustic imager body 1 on its top can be directly driven to complete the angle adjustment operation. After the adjustment is completed, release the thrust applied to the connecting sleeve 28, and according to the elastic reaction force, the first gear 25, the first gear ring 29 and the second gear ring 210 will coincide. At this time, the adjusted angle can be locked.

[0032] As Figure 5 shown, the connecting component includes a mounting base 31, the mounting base 31 is fixedly installed at the bottom of the bracket 23, and a connecting pipe 32 is fixedly installed at the bottom of the mounting base 31, which is convenient for support and connection with the components below.

[0033] As Figure 5 shown, the limiting component includes a connecting rod 33, the connecting rod 33 is fixedly installed at the top of the inner cavity of the connecting pipe 32, and a second gear 34 is fixedly installed at the bottom of the connecting rod 33. The bottom of the second gear 34 is rotatably connected to a circular plate 35. Through the adaptation of the teeth, the locking operation after rotation can be realized.

[0034] As Figure 5 shown, the elastic component includes a third gear ring 37, the third gear ring 37 is meshed outside the second gear 34, a sleeve 36 is fixedly installed outside the third gear ring 37, and a second spring 38 and a second telescopic rod 39 are fixedly installed at the bottom of the inner cavity of the sleeve 36. The second spring 38 is located outside the second telescopic rod 39, and the top of the second spring 38 and the second telescopic rod 39 is fixed to the bottom of the circular plate 35. According to the elastic reset principle, it can be pushed upward for locking after locking is required.

[0035] When performing the direction adjustment, pull down the mounting base 31 or the connecting pipe 32, and the connecting pipe 32 will drive the second gear 34 to move downward through the connecting rod 33, and the second spring 38 and the second telescopic rod 39 will be compressed by the circular plate 35, causing the second gear 34 to disengage from the third gear ring 37. Then the rotation operation can be performed. Since the connecting pipe 32 and the vertical rod 41 are in a sleeved state, the rotation can be directly performed. When rotated to the required angle position, release the downward force, and then according to the elastic reset principle, the second gear 34 and the third gear ring 37 will be adapted again, thus realizing the locking operation.

[0036] As Figure 6As shown, the first bearing component includes a vertical rod 41. The vertical rod 41 is fixedly installed at the bottom end of the sleeve 36. A first internal thread groove 42 is formed at the bottom of the vertical rod 41. A first external thread joint 43 is threadedly connected inside the first internal thread groove 42. The bottom end of the first external thread joint 43 is fixedly installed with an extension rod 44. A second internal thread groove 45 is formed at the bottom of the extension rod 44, which can assist subsequent hand-holding and facilitate the connection of extension parts.

[0037] As Figure 6 shown, the second bearing component includes a second external thread joint 46. The second external thread joint 46 is threadedly connected inside the second internal thread groove 45. The bottom end of the second external thread joint 46 is fixedly installed with a holding rod 47. A rubber sleeve 48 is fixedly installed on the outer side of the holding rod 47. It is convenient for disassembly and assembly according to the threaded connection relationship and is used for hand-holding. During operation, directly drive the first external thread joint 43 by the extension rod 44 to be threadedly connected with the first internal thread groove 42. And the extension rod 44 and the first external thread joint 43 are provided with a drag rod group, which can be sequentially connected downward to increase to the required length. Finally, use the holding rod 47 to connect through the second external thread joint 46 and the second internal thread groove 45. At this time, the assembly operation can be completed, and it can be assembled to the required length according to the need, thus facilitating people's use. The outer surface of the rubber sleeve 48 at the holding part is engraved with anti-slip lines to achieve an anti-slip effect.

[0038] Finally; As Figure 2 shown, one end of the photoacoustic imager body 1 is clamped with an outer cover 5. One end of the inner cavity of the outer cover 5 is fixedly installed with a sponge pad 6, which is beneficial to protecting the detection end or the end for installing the probe. The outer cover 5 and the sponge pad 6 are used to form a protection by being fitted and covered with the photoacoustic imager body 1.

[0039] The present invention provides a hand-held method for photoacoustic imaging, including the following steps: S1. Hand-held operation: First, threadedly connect the extension rod 44 with the vertical rod 41 through the first external thread joint 43 to increase the use length. Then, threadedly connect the holding rod 47 with the extension rod 44 through the second external thread joint 46 to assist in holding. Drive the photoacoustic imager body 1 to be in a preset position for detection at the position of the rubber sleeve 48 held by hand, and it can be adjusted according to the need. S2. When adjusting the angle, press the connecting sleeve 28 and compress the first spring 26 and the first telescopic rod 27. At this time, the connecting sleeve 28 drives the first gear ring 29 to disengage from the meshing state of the second gear ring 210. Then, rotate the shaft rod 24 to drive the first gear 25 to rotate. Drive the support seat 21 and the photoacoustic imager body 1 on the top to complete the angle rotation according to the meshing of the first gear 25 and the arc-shaped tooth plate 22. S3. When adjusting the direction, directly pull down the connecting pipe 32. The connecting pipe 32 drives the second gear 34 to press down through the connecting rod 33, synchronously compressing the second spring 38 and the second telescopic rod 39. And the second gear 34 and the third toothed ring 37 are disengaged from the meshing state. After directly rotating the mounting seat 31 to the required angle and releasing the downward pulling force, the second gear 34 and the third toothed ring 37 are meshed and locked according to the reaction force of the second spring 38.

[0040] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A handheld device for tomographic photoacoustic imaging of an object, characterized in that: It includes a photoacoustic imager body (1); The bottom of the photoacoustic imaging device body (1) is provided with a rotating mechanism (2) with an adjustable angle, the bottom of the rotating mechanism (2) is provided with a rotating mechanism (3) with an adjustable direction, and the bottom of the rotating mechanism (3) is provided with a hand-held holding mechanism (4); The rotating mechanism (2) comprises a supporting component, a rotating component and a positioning component, wherein the supporting component is arranged at the bottom of the photoacoustic imaging device body (1), the rotating component is arranged inside the supporting component, and the positioning component is arranged outside the supporting component; The rotating mechanism (3) comprises a connecting component, a limiting component and an elastic component, wherein the connecting component is arranged at the bottom of the supporting component, the limiting component is arranged inside the connecting component, and the elastic component is arranged at the bottom of the limiting component; The holding mechanism (4) comprises a first bearing component and a second bearing component, wherein the first bearing component is arranged at the bottom of the elastic component, and the second bearing component is arranged at the bottom of the first bearing component.

2. A handheld device for tomographic photoacoustic imaging of an object according to claim 1, characterized in that: The support assembly comprises a support seat (21), the support seat (21) being fixedly mounted on the bottom of the photoacoustic imager body (1), a bracket (23) being rotatably connected to the outer side of the support seat (21), and an arc-shaped toothed plate (22) being fixedly mounted on the bottom of the support seat (21).

3. A handheld device for tomographic photoacoustic imaging of an object according to claim 2, characterized in that: The rotating assembly comprises a shaft (24), the shaft (24) being rotatably connected to the inner side of the bracket (23), and a first gear (25) being fixedly mounted on the outer side of the shaft (24), the first gear (25) being meshed with the arc-shaped gear plate (22).

4. A handheld device for tomographic photoacoustic imaging of an object according to claim 3, characterized in that: The positioning assembly comprises a first spring (26) and a first telescopic rod (27), the first spring (26) and the first telescopic rod (27) are both fixedly mounted on one side of the bracket (23), the first spring (26) is located on the outside of the first telescopic rod (27), a connecting sleeve (28) is fixedly mounted on one end of the first spring (26) and the first telescopic rod (27), a first gear ring (29) is fixedly mounted on the inner side wall of the connecting sleeve (28), a second gear ring (210) is meshed on the inner side of the first gear ring (29), and the second gear ring (210) is fixedly mounted on the outer side of the shaft rod (24).

5. A handheld device for tomographic photoacoustic imaging of an object according to claim 1, characterized in that: The connection assembly comprises a mounting seat (31), wherein the mounting seat (31) is fixedly mounted on the bottom of the bracket (23), and a connecting pipe (32) is fixedly mounted on the bottom of the mounting seat (31).

6. A handheld device for tomographic photoacoustic imaging of an object according to claim 5, characterized in that: The limiting assembly comprises a connecting rod (33), wherein the connecting rod (33) is fixedly mounted on the top of the inner cavity of the connecting tube (32), a second gear (34) is fixedly mounted on the bottom end of the connecting rod (33), and a circular plate (35) is rotatably connected to the bottom of the second gear (34).

7. A handheld device for tomographic photoacoustic imaging of an object according to claim 6, characterized in that: The elastic component comprises a third gear ring (37), the third gear ring (37) meshing with the outer side of the second gear (34), a sleeve (36) fixedly mounted on the outer side of the third gear ring (37), a second spring (38) and a second telescopic rod (39) fixedly mounted on the bottom of the inner cavity of the sleeve (36), the second spring (38) being located on the outer side of the second telescopic rod (39), and the top ends of the second spring (38) and the second telescopic rod (39) being fixed to the bottom of the circular plate (35).

8. A handheld device for tomographic photoacoustic imaging of an object according to claim 1, characterized in that: The first bearing assembly comprises a vertical rod (41), the vertical rod (41) being fixedly mounted on the bottom end of the sleeve (36), the bottom of the vertical rod (41) being provided with a first internal thread groove (42), the internal thread of the first internal thread groove (42) being connected to a first external thread joint (43), the bottom end of the first external thread joint (43) being fixedly mounted with an extension rod (44), the bottom of the extension rod (44) being provided with a second internal thread groove (45).

9. A handheld device for tomographic photoacoustic imaging of an object according to claim 8, characterized in that: The second bearing assembly comprises a second external thread joint (46), the second external thread joint (46) being threadedly connected to the interior of the second internal thread groove (45), a holding rod (47) being fixedly mounted at the bottom end of the second external thread joint (46), and a rubber sleeve (48) being fixedly mounted on the outer side of the holding rod (47); An outer cover (5) is engaged with one end of the photoacoustic imaging device body (1), and a sponge pad (6) is fixedly mounted on one end of the inner cavity of the outer cover (5).

10. A handheld method for photoacoustic imaging, applied to the handheld device for tomographic photoacoustic imaging of an object according to any one of claims 1 to 9, characterized in that: The steps include: S1. Handheld operation: first, the extension rod (44) is threadedly connected to the vertical rod (41) through the first external threaded joint (43) to increase the usable length, and then the gripping rod (47) is threadedly connected to the extension rod (44) through the second external threaded joint (46) to assist gripping. The position of the handheld rubber sleeve (48) drives the photoacoustic imaging device body (1) to be in a preset position for detection, and can be adjusted according to needs; S2, when adjusting the angle, the connecting sleeve (28) is pressed and the first spring (26) and the first telescopic rod (27) are compressed. At this time, the connecting sleeve (28) drives the first gear ring (29) to disengage from the meshing state of the second gear ring (210), and then the shaft (24) is rotated to drive the first gear (25) to rotate. According to the meshing of the first gear (25) and the arc-shaped gear plate (22), the supporting seat (21) and the photoacoustic imaging device body (1) on the top are driven to complete the angle rotation; S3. When adjusting the direction, the connecting tube (32) is directly pulled downward, and the connecting tube (32) drives the second gear (34) to be pressed downward through the connecting rod (33), and the second spring (38) and the second telescopic rod (39) are simultaneously compressed, and the second gear (34) and the third gear ring (37) are disengaged. After the mounting seat (31) is directly rotated to a desired angle, the downward pulling force is released, and the second gear (34) and the third gear ring (37) are meshed and locked according to the reaction force of the second spring (38).

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