Condensation cylinder and optical lens

Abstract

The utility model relates to a condensation cylinder and an optical lens. Comprising a front telescopic cylinder, a rear telescopic cylinder, a rotating switch and a limiting cylinder; the front telescopic cylinder and the rear telescopic cylinder are coaxially mounted at the two ends of the rotating switch in a relative rotation manner respectively, and the rotating switch is rotated, so that the front telescopic cylinder and the rear telescopic cylinder get close to each other or get away from each other; the limiting cylinder and the rotating switch are coaxial and rotationally connected, and the limiting cylinder is nested between the front telescopic cylinder and the rear telescopic cylinder, is in sliding connection with the front telescopic cylinder and the rear telescopic cylinder in the axial direction and is used for limiting relative rotation of the front telescopic cylinder and the rear telescopic cylinder in the circumferential direction. The front telescopic cylinder and the rear telescopic cylinder can be synchronously driven by rotating the rotating switch, the light gathering effect can be rapidly achieved, meanwhile, circumferential rotation of the front telescopic cylinder and the rear telescopic cylinder is limited through the limiting cylinder, assembling is easy, and cost is low; and the multi-layer cylinder structure is assembled in a peak staggering and crossing mode, and the storage size is small.

Description

Technical Field

[0001] The utility model relates to the technical field of photographic equipment, and more specifically, to a focusing tube and an optical lens. Background Art

[0002] In order to adjust the focal length of the light and change the light effect, existing photographic lamps often use focusing accessories with different lenses, such as focusing tubes. The existing multi-stage telescopic focusing tube uses a metal connecting column to fix the inner tube to prevent the inner tube from rotating with the outer tube when the outer tube rotates. By setting a matching spiral rotating track on the contact surface of the inner and outer tubes, the two can achieve relative axial telescopic movement. However, the connecting column used in this solution is made of metal, which is costly and requires high assembly precision. Utility Model Content

[0003] In order to overcome the defects in the prior art, the utility model provides a focusing tube and an optical lens, which are simple and convenient to operate, low in cost and simple to assemble.

[0004] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0005] A focusing tube comprises a front telescopic tube, a rear telescopic tube, a rotary switch and a limit tube; the front telescopic tube and the rear telescopic tube are respectively coaxially and relatively rotatably installed at the two ends of the rotary switch, and the rotary switch is rotated so that the front telescopic tube and the rear telescopic tube are closer to or farther away from each other; the limit tube is coaxial with the rotary switch and is rotationally connected, the limit tube is nested between the front telescopic tube and the rear telescopic tube, and is respectively axially slidably connected to the front telescopic tube and the rear telescopic tube, so as to limit the relative rotation of the front telescopic tube and the rear telescopic tube along the circumferential direction.

[0006] According to the above technical solution, the front telescopic cylinder and the rear telescopic cylinder are connected to the rotary switch respectively. When the rotary switch is rotated, the front telescopic cylinder and the rear telescopic cylinder move closer to or farther from each other, thereby realizing the adjustment of the focal length; the limit cylinder is connected to the rotary switch coaxially, and is also connected to the front telescopic cylinder and the rear telescopic cylinder in a circumferential sliding manner respectively. When the rotary switch is rotated, the front telescopic cylinder and the rear telescopic cylinder move back and forth along the axial direction of the limit cylinder when they move closer to or farther from each other. The limit cylinder prevents the front telescopic cylinder and the rear telescopic cylinder from rotating relative to each other, ensuring that the two only change the assembly distance but not the assembly angle. Restricting circumferential rotation by means of the limit cylinder is lower in cost and assembly requirements than by means of the connecting column in the existing solution.

[0007] In one embodiment, the inner side wall and the outer side wall of the limiting cylinder are respectively provided with a first concave-convex structure and a second concave-convex structure extending in the axial direction; the outer circumferential surface of the rear telescopic cylinder and the inner circumferential surface of the front telescopic cylinder are respectively provided with a third concave-convex structure and a fourth concave-convex structure extending in the axial direction; the first concave-convex structure is slidably connected to the third concave-convex structure; the second concave-convex structure is slidably connected to the fourth concave-convex structure. The limiting cylinder is nested between the front telescopic cylinder and the rear telescopic cylinder to make the front telescopic cylinder and the rear telescopic cylinder relatively stationary in the circumferential direction; in the utility model, the inner side wall of the limiting cylinder and the outer circumferential surface of the rear telescopic cylinder, as well as the outer side wall of the limiting cylinder and the inner circumferential surface of the front telescopic cylinder are respectively provided with concave-convex structures that cooperate with each other and extend in the axial direction, which can not only stop the three from rotating with each other, but also play a role in guiding in the axial direction.

[0008] In one embodiment, the front telescopic cylinder and the rotary switch are respectively provided with a first guide rail and a second guide rail arranged in opposite spiral directions, and the rear telescopic cylinder and the rotary switch are respectively provided with a first guide groove and a second guide groove extending in opposite spiral directions; the first guide rail is located in the second guide groove, and the second guide rail is located in the first guide groove; when the rotary switch is rotated, the first guide rail moves along the second guide groove, and the second guide rail moves along the first guide groove, so that the front telescopic cylinder and the rear telescopic cylinder are close to or away from each other. The first guide rail on the front telescopic cylinder is located in the second guide groove on the rotary switch; the second guide rail on the rotary switch is located in the first guide groove of the rear telescopic cylinder, so that the three are nested with each other, and when the front telescopic cylinder and the rear telescopic cylinder are relatively stationary in the circumferential direction, the rotary switch is rotated, and the guide rails move along the guide grooves in which they are located, so that the front telescopic cylinder and the rear telescopic cylinder are close to or away from each other in the axial direction.

[0009] In one embodiment, the first concave-convex structure and the fourth concave-convex structure are both protruding sliders, and the second concave-convex structure and the third concave-convex structure are both limiting grooves; or, the first concave-convex structure and the fourth concave-convex structure are both limiting grooves; the second concave-convex structure and the third concave-convex structure are both protruding sliders.

[0010] In one embodiment, the limit cylinder is sleeved inside the rotary switch, and a gap is formed between the opposing circumferential surfaces of the two, and the front telescopic cylinder is nested in the gap and can move in the gap. The limit cylinder is rotatably sleeved inside the rotary switch, and the front telescopic cylinder is nested between the limit cylinder and the rotary switch, so that each structure can overlap and nest as much as possible, thereby saving materials and volume.

[0011] In one embodiment, the rotary switch is provided with a first clamping member, and the limiting cylinder is provided with a second clamping member; the first clamping member is clamped with the second clamping member to limit the axial sliding of the limiting cylinder relative to the rotary switch.

[0012] In one embodiment, a guide ring is fixedly connected to the inner side of the rear end of the rotary switch, i.e., the end away from the front telescopic tube, and the second guide rail is located on the inner side of the guide ring. The second guide groove is located on the inner side of the rotary switch, and the second guide groove extends from the front end of the rotary switch to the guide ring. In order to further enable the various structures to overlap as much as possible, a raised guide ring is provided on the rotary switch, and the second guide rail on the guide ring is connected to the first guide groove of the rear telescopic tube. This arrangement allows the rear telescopic tube to be located at the innermost side of the entire focusing tube, i.e., from the inside to the outside, the rear telescopic tube, the limit tube, the front telescopic tube, and the rotary switch are arranged in sequence, so that they can overlap and nest with each other, thereby minimizing the volume and saving materials to the greatest extent.

[0013] In one embodiment, a first annular boss is provided on the inner side wall of the end of the rotary switch away from the front telescopic cylinder, and the first annular boss is located between the guide ring and the front telescopic cylinder; a second annular boss is provided on the outer side wall of the end of the front telescopic cylinder away from the rotary switch. When the focusing cylinder is contracted to the minimum volume, that is, the distance between the front telescopic cylinder and the rear telescopic cylinder is the minimum, the front end of the rotary switch abuts against the second annular boss on the front telescopic cylinder; the rear end of the front telescopic cylinder abuts against the first annular boss on the rotary switch.

[0014] In one embodiment, an annular groove is formed between the first annular boss and the guide ring, a fixing ring is circumferentially slidably installed in the annular groove, and the first clamping member is arranged on the fixing ring. When the rotary switch is rotated, since the limit cylinder is connected with the second concave-convex structure and the third concave-convex structure on the front telescopic cylinder and the rear telescopic cylinder respectively through the first concave-convex structure and the second concave-convex structure, and the concave-convex structures restrict the circumferential rotation of each other, when the rotary switch is rotated, the fixing ring rotates relative to the rotary switch, thereby realizing the rotational connection between the limit cylinder and the rotary switch.

[0015] In one of the embodiments, the first clamping member is disposed on the first annular boss, and the first clamping member is an annular groove disposed along the first annular boss; the second clamping member is a buckle; the buckle is clamped in the annular groove and can slide along the annular groove.

[0016] In one embodiment, the first clamping member is an annular groove, and the annular groove is located between the first annular boss and the guide ring; the second clamping member is a fixing ring fixedly mounted on the limiting cylinder, and the fixing ring is nested in the annular groove and slidably connected with the annular groove.

[0017] In one of the embodiments, the guide ring is connected to the rotary switch via a thread; or, the guide ring is connected to the rotary switch via a bolt; or, the guide ring is connected to the rotary switch via adhesion or interference fit.

[0018] In one embodiment, the limiting cylinder is made of plastic material. The limiting cylinder is made of plastic material, which can reduce weight and cost.

[0019] In another embodiment, the utility model further provides an optical lens, comprising a convex lens, a Fresnel lens, and the above-mentioned focusing tube, wherein the convex lens is mounted on the rear telescopic tube, and the Fresnel lens is mounted on the front telescopic tube.

[0020] In one of the embodiments, a mounting portion for mounting the front end bayonet of the movie light and a toggle switch are also provided on the rear telescopic tube.

[0021] In one of the embodiments, the front telescopic tube is also provided with an attachment interface for superimposed assembly of photographic accessories.

[0022] Compared with the prior art, the beneficial effects are: the utility model provides a focusing tube and an optical lens, which can synchronously drive the front telescopic tube and the rear telescopic tube by rotating a rotary switch, and can quickly achieve a focusing effect. At the same time, the circumferential rotation of the front telescopic tube and the rear telescopic tube is limited by the limit tube, and the assembly is simple and the cost is low. The utility model adopts a multi-layer cylindrical structure for staggered cross assembly, and the storage volume is small. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the utility model in an expanded state.

[0024] Figure 2 It is a schematic diagram of the connection relationship of the utility model in the unfolded state.

[0025] Figure 3 The utility model is a schematic diagram of the connection relationship between the front telescopic cylinder, the rear telescopic cylinder and the limit cylinder.

[0026] Figure 4 It is a schematic diagram of the connection relationship between the limit cylinder and the rotary switch of the utility model.

[0027] Figure 5 It is a schematic diagram of the structure of the utility model in the storage state.

[0028] Figure 6 It is a schematic diagram of the connection relationship of the utility model in the storage state.

[0029] Figure 7 It is a schematic diagram of the structure of the limiting cylinder of the utility model.

[0030] Figure 8 It is a schematic diagram of the structure of the rear telescopic cylinder of the utility model.

[0031] Fig. 9 It is a schematic diagram of the structure of the front telescopic cylinder of the utility model.

[0032] Fig.10 It is a schematic diagram of the structure of the rotary switch of the utility model.

[0033] Figure numerals: 1. rear telescopic cylinder; 11. third concave-convex structure; 12. first guide groove; 13. mounting portion; 14. toggle switch; 2. front telescopic cylinder; 21. fourth concave-convex structure; 22. first guide rail; 23. second annular boss; 3. rotary switch; 31. second guide rail; 32. second guide groove; 33. guide rail ring; 34. first clamping member; 35. fixing ring; 36. first annular boss; 4. limiting cylinder; 41. first concave-convex structure; 42. second concave-convex structure; 43. second clamping member; 5. convex lens; 6. Fresnel lens. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. The utility model is described in one of the embodiments in combination with the specific implementation methods. Among them, the drawings are only used for exemplary descriptions, and only schematic diagrams are shown, not physical drawings, and cannot be understood as limitations on this patent; in order to better illustrate the embodiments of the utility model, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0035] In the description of the present utility model, it should be understood that if the terms "upper", "lower", "left", "right" and the like indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, it is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only used for exemplary explanations and cannot be understood as a limitation of this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances. In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text is to include three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or schemes that satisfy both A and B.

[0036] Embodiment 1:

[0037] like Figures 1 to 10 As shown, a focusing tube comprises a front telescopic tube 2, a rear telescopic tube 1, a rotary switch 3 and a limit tube 4; the front telescopic tube 2 and the rear telescopic tube 1 are respectively coaxially and relatively rotatably installed at the two ends of the rotary switch 3, and the rotary switch 3 is rotated to make the front telescopic tube 2 and the rear telescopic tube 1 approach or move away from each other; the limit tube 4 is coaxial with the rotary switch 3 and is rotationally connected, the limit tube 4 is nested between the front telescopic tube 2 and the rear telescopic tube 1, and is respectively axially slidably connected to the front telescopic tube 2 and the rear telescopic tube 1, so as to limit the relative rotation of the front telescopic tube 2 and the rear telescopic tube 1 along the circumferential direction.

[0038] According to the above technical solution, the front telescopic cylinder 2 and the rear telescopic cylinder 1 are connected to the rotary switch 3 respectively. When the rotary switch 3 is rotated, the front telescopic cylinder 2 and the rear telescopic cylinder 1 are moved closer to or farther from each other, thereby realizing the adjustment of the focal length; the limit cylinder 4 is coaxially connected to the rotary switch 3 and is also circumferentially slidably connected to the front telescopic cylinder 2 and the rear telescopic cylinder 1 respectively. When the rotary switch 3 is rotated, the front telescopic cylinder 2 and the rear telescopic cylinder 1 move back and forth along the axial direction of the limit cylinder 4 when they are moved closer to or farther from each other. The limit cylinder 4 prevents the front telescopic cylinder 2 and the rear telescopic cylinder 1 from rotating relative to each other, ensuring that the two only change the assembly distance but not the assembly angle. Restricting the circumferential rotation by the limit cylinder 4 is lower in cost and assembly requirements than by the connecting column in the existing solution.

[0039] like Figure 3 , Figures 7 to 9As shown, the inner side wall and the outer side wall of the limiting cylinder 4 are respectively provided with a first concavo-convex structure 41 and a second concavo-convex structure 42 extending in the axial direction; the outer circumference of the rear telescopic cylinder 1 and the inner circumference of the front telescopic cylinder 2 are respectively provided with a third concavo-convex structure 11 and a fourth concavo-convex structure 21 extending in the axial direction; the first concavo-convex structure 41 is slidably connected with the third concavo-convex structure 11; the second concavo-convex structure 42 is slidably connected with the fourth concavo-convex structure 21. The limiting cylinder 4 is nested between the front telescopic cylinder 2 and the rear telescopic cylinder 1, and is used to make the front telescopic cylinder 2 and the rear telescopic cylinder 1 relatively stationary in the circumferential direction; in the utility model, the inner side wall of the limiting cylinder 4 and the outer circumference of the rear telescopic cylinder 1, and the outer side wall of the limiting cylinder 4 and the inner circumference of the front telescopic cylinder 2 are respectively provided with concavo-convex structures that cooperate with each other and extend in the axial direction, which can not only stop the three from rotating with each other, but also play a role of guiding in the axial direction.

[0040] Among them, the first concave-convex structure 41 and the fourth concave-convex structure 21 are both protruding sliders, and the second concave-convex structure 42 and the third concave-convex structure 11 are both limiting grooves; or, the first concave-convex structure 41 and the fourth concave-convex structure 21 are both limiting grooves; the second concave-convex structure 42 and the third concave-convex structure 11 are both protruding sliders.

[0041] like Figure 2 , Figure 8 , Fig. 9 and Fig.10 As shown, the front telescopic cylinder 2 and the rotary switch 3 are respectively provided with a first guide rail 22 and a second guide rail 31 arranged in opposite spiral directions, and the rear telescopic cylinder 1 and the rotary switch 3 are respectively provided with a first guide groove 12 and a second guide groove 32 extending in opposite spiral directions; the first guide rail 22 is located in the second guide groove 32, and the second guide rail 31 is located in the first guide groove 12; when the rotary switch 3 is rotated, the first guide rail 22 moves along the second guide groove 32, and the second guide rail moves along the first guide groove 12, so that the front telescopic cylinder 2 and the rear telescopic cylinder 1 are close to or away from each other. The first guide rail 22 on the front telescopic cylinder 2 is located in the second guide groove 32 on the rotary switch 3; the second guide rail on the rotary switch 3 is located in the first guide groove 12 of the rear telescopic cylinder 1, so that the three are nested with each other, and when the front telescopic cylinder 2 and the rear telescopic cylinder 1 are relatively stationary along the circumferential direction, the rotary switch 3 is rotated, and the guide rails move along the guide grooves in which they are located, so that the front telescopic cylinder 2 and the rear telescopic cylinder 1 are close to or away from each other along the axial direction.

[0042] like Figure 2 and Figure 6 As shown, the limit cylinder 4 is sleeved inside the rotary switch 3, and a gap is formed between the opposite circumferential surfaces of the two, and the front telescopic cylinder 2 is nested in the gap and can move in the gap. The limit cylinder 4 is rotatably sleeved inside the rotary switch 3, and the front telescopic cylinder 2 is nested between the limit cylinder 4 and the rotary switch 3, so that each structure can overlap and nest as much as possible, thereby saving materials and volume.

[0043] like Figure 4 , Figure 7 and Fig.10 As shown, the rotary switch 3 is provided with a first clamping member 34 , and the limiting cylinder 4 is provided with a second clamping member 43 ; the first clamping member 34 is clamped with the second clamping member 43 to limit the axial sliding of the limiting cylinder 4 relative to the rotary switch 3 .

[0044] like Figure 2 , Figure 4 , Figure 6 as well as Fig.10 As shown, the rear end of the rotary switch 3, i.e., the inner side of one end away from the front telescopic cylinder 2, is fixedly connected with a guide ring 33, the second guide rail 31 is located on the inner side of the guide ring 33, the second guide groove 32 is located on the inner side of the rotary switch 3, and the second guide groove 32 extends from the front end of the rotary switch 3 to the guide ring 33. In order to further enable each structure to overlap as much as possible, a raised guide ring 33 is provided on the rotary switch 3, and the second guide rail 31 on the guide ring 33 is connected to the first guide groove 12 of the rear telescopic cylinder 1. In this way, the rear telescopic cylinder 1 can be located at the innermost side of the entire focusing cylinder, that is, from the inside to the outside, the rear telescopic cylinder 1, the limit cylinder 4, the front telescopic cylinder 2, and the rotary switch 3 are arranged in sequence, so that they can overlap and nest with each other, thereby minimizing the volume and saving materials to the greatest extent.

[0045] like Figure 6 As shown, a first annular boss 36 is provided on the inner side wall of the end of the rotary switch 3 away from the front telescopic cylinder 2, and the first annular boss 36 is located between the guide ring 33 and the front telescopic cylinder 2; a second annular boss 23 is provided on the outer side wall of the end of the front telescopic cylinder 2 away from the rotary switch 3. When the focusing cylinder is retracted to the smallest volume, that is, when the distance between the front telescopic cylinder 2 and the rear telescopic cylinder 1 is the smallest, the front end of the rotary switch 3 abuts against the second annular boss 23 on the front telescopic cylinder 2; and the rear end of the front telescopic cylinder 2 abuts against the first annular boss 36 on the rotary switch 3.

[0046] The guide ring 33 is connected to the rotary switch 3 via threads; or, the guide ring 33 is connected to the rotary switch 3 via bolts; or, the guide ring 33 is connected to the rotary switch 3 via adhesion or interference fit.

[0047] In this embodiment, the limiting cylinder 4 is made of plastic material. The limiting cylinder 4 is made of plastic material, which can reduce weight on the one hand and reduce costs on the other hand.

[0048] Example 2

[0049] The other structures of this embodiment are the same as those of embodiment 1, except that, in this embodiment, Figure 4As shown, an annular groove is formed between the first annular boss 36 and the guide ring 33, a fixing ring 35 is circumferentially slidably installed in the annular groove, and a first clamping member 34 is provided on the fixing ring 35. Among them, the first clamping member 34 is a clamping groove, and the second clamping member 43 is a buckle. When the rotary switch 3 is rotated, since the limit cylinder 4 is connected with the second concave-convex structure 42 and the third concave-convex structure 11 on the front telescopic cylinder 2 and the rear telescopic cylinder 1 through the first concave-convex structure 41 and the second concave-convex structure 42 respectively, and the concave-convex structures limit the circumferential rotation of each other, when the rotary switch 3 is rotated, the fixing ring 35 rotates relative to the rotary switch 3, thereby realizing the rotation connection between the limit cylinder 4 and the rotary switch 3.

[0050] Example 3

[0051] This embodiment is the same as Embodiment 1 in other structures, except that, in this embodiment, the first clamping member 34 is provided on the first annular boss 36, and the first clamping member 34 is an annular groove provided along the first annular boss 36; the second clamping member 43 is a buckle; the buckle is clamped in the annular groove and can slide along the annular groove.

[0052] Example 4

[0053] The other structures of this embodiment are the same as those of the first embodiment, except that, in this embodiment, the first clamping member 34 is an annular groove, which is located between the first annular boss 36 and the guide ring 33; the second clamping member 43 is a fixing ring 35 fixedly mounted on the limiting cylinder 4, and the fixing ring 35 is nested in the annular groove and is slidably connected with the annular groove.

[0054] Example 5

[0055] like Figure 1 , Figure 2 , Figure 5 and Figure 6 As shown, this embodiment provides an optical lens, including a convex lens 5, a Fresnel lens 6, and the focusing tube of embodiment 1, wherein the convex lens 5 is mounted on the rear telescopic tube 1, and the Fresnel lens 6 is mounted on the front telescopic tube 2. The rear telescopic tube 1 is also provided with a mounting portion 13 for mounting the front end bayonet of the film and television light, and a toggle switch 14. The front telescopic tube 2 is also provided with an attachment interface for stacking and assembling photographic accessories.

[0056] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0057] Obviously, the above embodiments of the utility model are only examples for clearly explaining the utility model, and are not intended to limit the implementation methods of the utility model. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to list all the implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the utility model should be included in the protection scope of the claims of the utility model.

Claims

1. A focusing tube, characterized in that: The invention comprises a rear telescopic cylinder (1), a front telescopic cylinder (2), a rotary switch (3) and a limit cylinder (4); the front telescopic cylinder (2) and the rear telescopic cylinder (1) are respectively coaxially and relatively rotatably mounted at two ends of the rotary switch (3); the rotary switch (3) is rotated so that the front telescopic cylinder (2) and the rear telescopic cylinder (1) are moved closer to or farther from each other; the limit cylinder (4) is coaxially and rotatably connected to the rotary switch (3); the limit cylinder (4) is nested between the front telescopic cylinder (2) and the rear telescopic cylinder (1), and is respectively slidably connected to the front telescopic cylinder (2) and the rear telescopic cylinder (1) along the axial direction, so as to limit the relative rotation of the front telescopic cylinder (2) and the rear telescopic cylinder (1) along the circumferential direction.

2. The focusing tube according to claim 1, characterized in that: A first concave-convex structure (41) and a second concave-convex structure (42) extending in the axial direction are respectively provided on the inner side wall and the outer side wall of the limiting cylinder (4); a third concave-convex structure (11) and a fourth concave-convex structure (21) extending in the axial direction are respectively provided on the outer peripheral surface of the rear telescopic cylinder (1) and the inner peripheral surface of the front telescopic cylinder (2); the first concave-convex structure (41) is slidably connected to the third concave-convex structure (11); and the second concave-convex structure (42) is slidably connected to the fourth concave-convex structure (21).

3. The focusing tube according to claim 2, characterized in that: The front telescopic cylinder (2) and the rotary switch (3) are respectively provided with a first guide rail (22) and a second guide rail (31) arranged in opposite spiral directions, and the rear telescopic cylinder (1) and the rotary switch (3) are respectively provided with a first guide groove (12) and a second guide groove (32) extending in opposite spiral directions; the first guide rail (22) is located in the second guide groove (32), and the second guide rail (31) is located in the first guide groove (12); when the rotary switch (3) is rotated, the first guide rail (22) moves along the second guide groove (32), and the second guide rail (31) moves along the first guide groove (12), so that the front telescopic cylinder (2) and the rear telescopic cylinder (1) are moved closer to or farther from each other.

4. The focusing tube according to claim 2, characterized in that: The first concave-convex structure (41) and the fourth concave-convex structure (21) are both convex sliders, and the second concave-convex structure (42) and the third concave-convex structure (11) are both limiting grooves; or, the first concave-convex structure (41) and the fourth concave-convex structure (21) are both limiting grooves; and the second concave-convex structure (42) and the third concave-convex structure (11) are both convex sliders.

5. The focusing tube according to claim 3, characterized in that: The limiting cylinder (4) is sleeved on the inner side of the rotary switch (3), and a gap is formed between the relative circumferential surfaces of the two, and the front telescopic cylinder (2) is nested in the gap and can move in the gap.

6. The focusing tube according to claim 5, characterized in that: The rotary switch (3) is provided with a first clamping member (34), and the limiting cylinder (4) is provided with a second clamping member (43); the first clamping member (34) is clamped with the second clamping member (43) to limit the axial sliding of the limiting cylinder (4) relative to the rotary switch (3).

7. The light collecting tube according to claim 6, characterized in that: A guide rail ring (33) is fixedly connected to the inner side of the rear end of the rotary switch (3), i.e., the end away from the front telescopic cylinder (2); the second guide rail (31) is located on the inner side of the guide rail ring (33); the second guide groove (32) is located on the inner side of the rotary switch (3); and the second guide groove (32) extends from the front end of the rotary switch (3) to the guide rail ring (33).

8. The focusing tube according to claim 7, characterized in that: A first annular boss (36) is provided on the inner side wall of the end of the rotary switch (3) away from the front telescopic cylinder (2), and the first annular boss (36) is located between the guide ring (33) and the front telescopic cylinder (2); and a second annular boss (23) is provided on the outer side wall of the end of the front telescopic cylinder (2) away from the rotary switch (3).

9. The focusing tube according to claim 8, characterized in that: An annular groove is formed between the first annular boss (36) and the guide rail ring (33), a fixing ring (35) is circumferentially slidably mounted in the annular groove, and the first clamping member (34) is fixedly mounted on the fixing ring (35).

10. The focusing tube according to claim 8, characterized in that: The first clamping member (34) is arranged on the first annular boss (36), and the first clamping member (34) is an annular clamping groove arranged along the first annular boss (36); the second clamping member (43) is a buckle; the buckle is clamped in the annular clamping groove and can slide along the annular clamping groove.

11. The light collecting tube according to claim 8, characterized in that: The first clamping member (34) is an annular groove, and the annular groove is located between the first annular boss (36) and the guide ring (33); the second clamping member (43) is a fixing ring (35) fixedly mounted on the limiting cylinder (4), and the fixing ring (35) is nested in the annular groove and is slidably connected to the annular groove.

12. The light collecting tube according to claim 7, characterized in that: The guide ring (33) is connected to the rotary switch (3) via a thread; or, the guide ring (33) is connected to the rotary switch (3) via a bolt; or, the guide ring (33) is connected to the rotary switch (3) by means of adhesion or interference fit.

13. The focusing tube according to any one of claims 1 to 12, characterized in that: The limiting cylinder (4) is made of plastic material.

14. An optical lens, characterized in that: It comprises a convex lens (5), a Fresnel lens (6), and a focusing tube as described in any one of claims 1 to 13, wherein the convex lens (5) is mounted on the rear telescopic tube (1), and the Fresnel lens (6) is mounted on the front telescopic tube (2).

15. The optical lens according to claim 14, characterized in that: The rear telescopic tube (1) is also provided with a mounting portion (13) for mounting the front end bayonet of the movie light, and a toggle switch (14).

16. The optical lens according to claim 14, characterized in that: The front telescopic tube (2) is also provided with an attachment interface for superimposing and assembling photographic accessories.

Images