Patent Publication Number: US-2022229281-A1

Title: Optical device and method of manufacturing tubular part-using product

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Japan application serial no. 2021-004758, filed on Jan. 15, 2021. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND 
     Technical Field 
     The disclosure relates to an optical device and a method of manufacturing a tubular part-using product. 
     Description of Related Art 
     Conventionally, regarding optical devices such as an optical sight installed on a hunting gun and a sports gun, a configuration provided with an adjusting mechanism for focus adjustment, ballistic correction, etc. is known (see, for example, Patent Document 1: Japanese Patent Application Laid-Open No. 2004-150699). Further, Patent Document 1 discloses a lock mechanism of the adjusting mechanism for focus adjustment. 
     When a lock mechanism is provided for the adjusting mechanism of the optical device, for example, it is possible to appropriately prevent an adjustment result from being displaced due to unintentional contact of the user&#39;s hand or an object with an operating part for adjustment. However, depending on the configuration of the lock mechanism, for example, sometimes the user may be given an impression that locking has been completed while it is actually in the unlocked state. As a result, the adjusting mechanism may not be appropriately locked. Therefore, conventionally, there has been a demand for a configuration capable of more appropriately adjusting the configuration for adjusting the function of the optical device. 
     SUMMARY 
     The configuration for adjusting the function of the optical device may be, for example, a configuration using a rotating operation part that rotates according to a user&#39;s operation. In this case, the lock mechanism may be realized by using, for example, recesses-projections formed on a rotating side tubular part which is a tubular part that rotates together with a rotating operation part, and recesses-projections formed on a fixed side tubular part which is a non-rotating tubular part. Specifically, in this case, for example, the rotating operation part and the rotating side tubular part may be moved forward and backward in a direction parallel to an axial direction of the rotating side tubular part, and by engagement between the recesses-projections of the rotating side tubular part and the recesses-projections of the fixed side tubular part at a predetermined position, rotation of the rotating operation part can be prohibited. Further, in this case, for example, by an operation of pushing the rotating operation part by the user, one of the rotating side tubular part and the fixed side tubular part may accommodate at least a part of the other, and the recesses-projections of the rotating side tubular part and the recesses-projections of the fixed side tubular part may be engaged with each other. With such a configuration, for example, the lock mechanism of the configuration for adjusting the function of the optical device can be appropriately realized. 
     However, in the case of such a lock mechanism, for example, before the recesses-projections of the rotating side tubular part and the recesses-projections of the fixed side tubular part are surely engaged with each other, the user may be given an impression that it is in the locked state. Specifically, for example, at the time when the rotating side tubular part and the fixed side tubular part come into contact with each other during the operation of pushing the rotating operation part by the user, as the projection of the recesses-projections of the rotating side tubular part and the projection of the recesses-projections of the fixed side tubular part collide with each other, the user may be given the impression that the pushing has been completed. As a result, while actually in the unlocked state, the user may be given the impression of being in the locked state. 
     In this regard, the inventors of the present application have conducted diligent research on a configuration in which such misrecognition is less likely to occur. Then, it is conceivable to use a configuration in which the recesses-projections of the rotating side tubular part and the fixed side tubular part are more naturally engaged with each other after the rotating side tubular part and the fixed side tubular part come into contact with each other. Specifically, as such a configuration, of the rotating side tubular part and the fixed side tubular part, at least the tubular part on which recesses-projections are formed on an outer peripheral surface may use a configuration in which the width of the projection gradually decreases toward an end part on a side close to the other tubular part. With this configuration, for example, after the rotating side tubular part and the fixed side tubular part come into contact with each other, the recesses-projections of the two can be more naturally engaged with each other. Further, for example, it is possible to appropriately prevent giving the user an impression of being in the locked state while it is actually in the unlocked state. 
     Further, the inventors of the present application have found features for obtaining such an effect through further diligent research and have obtained the disclosure. To solve the above problems, the disclosure relates to an optical device, which is an optical device enabling a user to visually recognize a target object, including an optical system, a housing, and an operation adjusting part. The optical system enables the user to visually recognize the target object. The housing houses the optical system. The operation adjusting part adjusts a function of the optical device according to an operation of the user. The operation adjusting part includes a rotating operation part, an adjusting mechanism, a first tubular part, and a second tubular part. The rotating operation part rotates according to an operation of the user. The adjusting mechanism adjusts the function of the optical device by moving a part of the optical device according to an amount of rotation of the rotating operation part. The first tubular part is in a tubular shape and is formed with recesses-projections on at least a part of an outer peripheral surface. The second tubular part is in a tubular shape and is formed with inner peripheral recesses-projections on at least a part of an inner peripheral surface, the inner peripheral recesses-projections being recesses-projections having a shape that engages with outer peripheral recesses-projections which are the recesses-projections on the outer peripheral surface of the first tubular part. A rotating side tubular part, which is one of the first tubular part and the second tubular part, has an axial direction parallel to a rotation axis of the rotating operation part and has a position fixed to the rotating operation part to rotate together with the rotating operation part. Another of the first tubular part and the second tubular part has an axial direction aligned with the rotating side tubular part and is arranged at a position fixed to the housing. The outer peripheral recesses-projections of the first tubular part are recesses-projections of which projections and recesses extending in a direction parallel to an axial direction of the first tubular part are alternately arranged in a circumferential direction of the outer peripheral surface. The rotating operation part is capable of moving forward and backward in a direction parallel to the axial direction of the first tubular part, and according to an operation of the user, moves together with the rotating side tubular part to at least a rotatable position at which rotation of the rotating operation part is made possible by separation between the outer peripheral recesses-projections and the inner peripheral recesses-projections, and a rotation prohibited position at which rotation of the rotating operation part is prohibited by engagement between the outer peripheral recesses-projections and the inner peripheral recesses-projections. At least in a vicinity of an end part on a side close to the second tubular part, a width of the projection of the outer peripheral recesses-projections of the first tubular part gradually decreases toward the end part. 
     In this configuration, with the width of the projection of the outer peripheral recesses-projections of the first tubular part gradually decreasing toward the end part, for example, in the operation of moving the rotating operation part from the rotatable position to the rotation prohibited position, the outer peripheral recesses-projections of the first tubular part and the inner peripheral recesses-projections of the second tubular part can be more naturally engaged. Accordingly, for example, it is possible to appropriately prevent giving the user the impression of being in the locked state while it is actually in the unlocked state. Therefore, with such a configuration, for example, it is possible to appropriately realize a configuration capable of more appropriately adjusting a configuration for adjusting the function of the optical device. 
     Such an optical device may be, for example, an optical sight used by being attached to a gun Further, the operation adjusting part may be, for example, an adjusting part for performing impact position adjustment in the optical sight. With this configuration, for example, when performing impact position adjustment on the optical sight, the lock mechanism can be realized more appropriately. Further, the operation adjusting part may also be, for example, an adjusting part for purposes other than impact position adjustment in the optical sight. In this case, the operation adjusting part may be, for example, a focus adjusting part, an illumination adjusting part, etc. Further, the operation adjusting part may also be an adjusting part other than the above. Further, the operation adjusting part may also be, for example, an adjusting part in an optical device other than the optical sight. 
     Further, in this configuration, specifically, for example, the second tubular part is the rotating side tubular part. Further, at least at a part other than the vicinity of the end part on the side close to the second tubular part, for example, the projections of the outer peripheral recesses-projections of the first tubular part are arranged at a constant cycle in the circumferential direction with a constant width in the circumferential direction. Then, in the vicinity of the end part on the side close to the second tubular part, the width of the projection of the outer peripheral recesses-projections of the first tubular part in the circumferential direction gradually decreases toward the end part as described above. In this case, the width of the recess of the outer peripheral recesses-projections in the circumferential direction gradually increases, for example, toward the end part as the width of the adjacent projections decreases. Further, when moving the rotating operation part from the rotatable position to the rotation prohibited position, for example, the outer peripheral recesses-projections of the first tubular part guide movement of the second tubular part by the projections of which the width gradually decreases toward the end part so that the outer peripheral recesses-projections and the inner peripheral recesses-projections are engaged with each other. With this configuration, for example, when moving the rotating operation part from the rotatable position to the rotation prohibited position, the outer peripheral recesses-projections of the first tubular part and the inner peripheral recesses-projections of the second tubular part can be appropriately and naturally engaged with each other. 
     Further, at least in the vicinity of the end part on the side close to the second tubular part, a depth and a width of the recess of the outer peripheral recesses-projections of the first tubular part gradually increase toward the end part, for example. By forming such a recess, for example, a projection of which the width gradually decreases toward the end part can be appropriately formed. Specifically, the recess of the outer peripheral recesses-projections of the first tubular part is a recess in a shape of a V-shaped groove of which a width gradually increases as a distance from a bottom increases. Then, in this case, at least in the vicinity of the end part on the side close to the second tubular part, for example, with a position of the bottom of the recess in a shape of a V-shaped groove gradually becoming deeper toward the end part, the depth and the width of the recess of the outer peripheral recesses-projections of the first tubular part gradually increase toward the end part. By forming such a recess, for example, a projection of which the width gradually decreases toward the end part can be formed more appropriately. 
     Further, the features of the disclosure may also be considered by paying attention to, for example, steps of creating the first tubular part and the like. Further, in this case, not only the configuration of the optical device, but it is also possible to consider the features of a method of manufacturing a tubular part-using product. In this case, for example, the disclosure relates to a method of manufacturing a tubular part-using product, which is a product using a plurality of tubular parts, the method including the following steps. In a first tubular part creating step, a first tubular part in a tubular shape is created to be formed with recesses-projections on at least a part of an outer peripheral surface. In a second tubular part creating step, a second tubular part in a tubular shape is created to be formed with inner peripheral recesses-projections on at least a part of an inner peripheral surface, the inner peripheral recesses-projections being recesses-projections having a shape that engages with outer peripheral recesses-projections which are the recesses-projections on the outer peripheral surface of the first tubular part. The outer peripheral recesses-projections of the first tubular part are recesses-projections of which projections and recesses extending in a direction parallel to an axial direction of the first tubular part are alternately arranged in a circumferential direction of the outer peripheral surface. In the first tubular part creating step, a cutting tool having a blade for cutting is used; with the blade pressed against the first tubular part to be processed, by moving the blade relative to the first tubular part in a direction gradually away from a central axis of the first tubular part while advancing in a direction parallel to the axial direction of the first tubular part, a part of the recess of the outer peripheral recesses-projections of the first tubular part is formed; and afterwards, with the blade pressed against the first tubular part, by keeping a distance from the central axis of the first tubular part constant and moving the blade relative to the first tubular part, another part of the recess of the outer peripheral recesses-projections is formed, so that at least in a vicinity of an end part, the projection of the outer peripheral recesses-projections of the first tubular part is formed so that a width of the projection gradually decreases toward the end part. 
     With this configuration, for example, it is possible to appropriately form, on the first tubular part, outer peripheral recesses-projections having a projection of which the width gradually decreases toward the end part. The blade of the cutting tool may be, for example, a blade in a shape that forms a recess in a shape of a V-shaped groove of which a width gradually increases as a distance from a bottom increases by moving relative to a work piece while being pressed against the work piece. Further, in this case, in the first tubular part creating step, for example, the recess of the outer peripheral recesses-projections of the first tubular part may be formed so that a depth and a width of the recess gradually increase toward the end part. With this configuration, for example, the outer peripheral recesses-projections of the first tubular part can be formed more appropriately. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view showing an example of a configuration of an optical sight  10  according to an embodiment of the disclosure. 
         FIG. 2( a )  and  FIG. 2( b )  are views showing components constituting a main part of an impact position adjusting part  22 .  FIG. 2( a )  and  FIG. 2( b )  are a perspective view and a cross-sectional view showing an example of components constituting a main part of the impact position adjusting part  22 . 
         FIG. 3( a )  and  FIG. 3( b )  are views showing a lock mechanism of the impact position adjusting part  22 .  FIG. 3( a )  is a cross-sectional view showing the impact position adjusting part  22  in an unlocked state.  FIG. 3( b )  is a cross-sectional view showing the impact position adjusting part  22  in a locked state. 
         FIG. 4( a )  and  FIG. 4( b )  are views showing misrecognition that occurs at the time of locking the impact position adjusting part  22 .  FIG. 4( a )  shows an example of a state in which locking is correctly performed.  FIG. 4( b )  shows an example of misrecognition that occurs at the time of locking. 
         FIG. 5  is a simplified view showing the operation at the time of locking the impact position adjusting part  22 . 
         FIG. 6( a )  and  FIG. 6( b )  are views showing an outline of an operation of forming a recess of outer peripheral recesses-projections of a fixed tubular part  106 .  FIG. 6( a )  and  FIG. 6( b )  show the positional relationship between the fixed tubular part  106  and a bit  502  at the time of forming the outer peripheral recesses-projections. 
         FIG. 7  is a view showing an operation of forming the outer peripheral recesses-projections of the fixed tubular part  106 . 
         FIG. 8  is a view showing an example of a configuration of a fixed tubular part  606  formed with outer peripheral recesses-projections  612  having a shape different from that of the present example. 
         FIG. 9  is a view showing an example of the configuration of the fixed tubular part  106  in the present example. 
         FIG. 10( a ) ,  FIG. 10( b ) , and  FIG. 10( c )  are simplified views showing shapes of a projection  622  and a recess  624  of the outer peripheral recesses-projections  612  of the fixed tubular part  606 .  FIG. 10( a )  is a top view showing the projection  622  and the recess  624  as viewed from the normal direction of the outer peripheral surface of the fixed tubular part  606 .  FIG. 10( b )  and  FIG. 10( c )  are cross-sectional views at positions of line AA and line BB. 
         FIG. 11( a ) ,  FIG. 11( b ) , and  FIG. 11( c )  are simplified views showing the shapes of the projection  222  and the recess  224  of the outer peripheral recesses-projections  204  of the fixed tubular part  106 .  FIG. 11( a )  is a top view showing the projection  222  and the recess  224  as viewed from the normal direction of the outer peripheral surface of the fixed tubular part  106 . 
         FIG. 11( b )  and  FIG. 11( c )  are cross-sectional views at positions of line AA and line BB. 
         FIG. 12( a )  and  FIG. 12( b )  are views showing modified examples of the configuration of the impact position adjusting part  22 .  FIG. 12( a )  and  FIG. 12( b )  show modified examples of the configurations of the rotating tubular part  124  and the fixed tubular part  106  in the impact position adjusting part  22 . 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     According to embodiments of the disclosure, for example, it is possible to appropriately realize a configuration capable of more appropriately adjusting a configuration for adjusting a function of an optical device. 
     Hereinafter, embodiments according to the disclosure will be described with reference to the drawings.  FIG. 1  shows an example of a configuration of an optical sight  10  according to an embodiment of the disclosure. The optical sight  10  is an example of an optical device that enables a user to visually recognize a target object and is used by being attached to a gun such as a hunting gun or a sports gun. Specifically, in the present example, the optical sight  10  is attached to a long-range shooting gun (e.g., a rifle) and magnifies a distant target object of shooting such as a hunting prey or a shooting target to enable a user to visually recognize it. In this case, the optical sight  10  may be, for example, an aiming telescope having a telescopic function. The optical sight  10  may also be, for example, a scope (e.g., a scope for a rifle) attached to a gun. Further, the optical sight  10  may have the same or similar characteristics as a known optical sight  10  except for the points described below. For example, except for the points described below, configurations having the same functions as known configurations may be suitably used as the configurations of each part of the optical sight  10 . 
     Further, in the present example, the optical sight  10  includes an optical system  12 , a housing  14 , a plurality of impact position adjusting parts  22 , a focus adjusting part  24 , an illumination adjusting part  26 , a magnification adjusting part  28 , and a diopter adjusting part  30 . The optical system  12  is an optical system including a plurality of lenses such as an eyepiece lens and an objective lens, and by orienting the objective lens side toward the front side of the gun and orienting the eyepiece lens side toward the rear side of the gun, a user who is the shooter of the gun can visually recognize the target object of shooting. The housing  14  is a housing that houses the optical system  12 . Further, in the present example, the housing  14  is fixedly attached to a predetermined position on the gun by using, for example, a mount (not shown). 
     Each of the plurality of impact position adjusting parts  22 , the focus adjusting part  24 , the illumination adjusting part  26 , the magnification adjusting part  28 , and the diopter adjusting part  30  is an example of an operation adjusting part and adjusts the function of the optical sight  10  according to the user&#39;s operation. In the present example, the adjustment of the function of the optical sight  10  may refer to, for example, adjustment of the optical characteristics and aiming of the optical sight  10 . Further, among these configurations for adjustment, the impact position adjusting parts  22  are adjusting parts for performing impact position adjustment, which is adjustment of the relationship between an impact point (impact position) of a bullet of the gun to which the optical sight  10  is attached and an optical axis direction of the optical sight  10 . In this case, for example, the impact point may be adjusted by performing adjustment with the impact position adjusting parts  22  according to a distance to a target point. The impact position adjusting part  22  may be, for example, an adjusting part that performs adjustment for aligning the target point of the gun and the impact point. Further, the impact position adjusting part  22  may also be, for example, an adjusting part that adjusts the optical axis direction of the optical sight  10  with respect to the orientation of a barrel. Further, each of the impact position adjusting parts  22  may be, for example, an adjusting part that adjusts each of an elevation angle and a deflection angle of the optical axis direction of the optical sight  10 . 
     Further, in the present example, the optical sight  10  includes, as the plurality of impact position adjusting parts  22 , an impact position adjusting part  22  for adjusting the impact position in the horizontal direction and an impact position adjusting part  22  for adjusting the impact position in the vertical direction. Specifically, in the case of the configuration shown in  FIG. 1 , the impact position adjusting part  22  located on one side in the left-right direction of the optical sight  10  while attached to the gun is the impact position adjusting part  22  for adjusting the impact position in the horizontal direction. This impact position adjusting part  22  may be located, for example, at a position opposite to the focus adjusting part  24  and the illumination adjusting part  26  with the housing  14  interposed therebetween. Further, the impact position adjusting part  22  located on the upper side in the vertical direction while attached to the gun is the impact position adjusting part  22  for adjusting the impact position in the vertical direction. Further, in the present example, each of the impact position adjusting parts  22  has a predetermined lock mechanism. A more specific configuration and the lock mechanism of the impact position adjusting part  22  will be described in more detail later. Further, except for the lock mechanism, the impact position adjusting parts  22  may have, for example, the same or similar characteristics as known impact position adjusting parts. 
     Further, the focus adjusting part  24  is an adjusting part for adjusting the focus of the optical sight  10 . The illumination adjusting part  26  is an adjusting part for adjusting the illumination function. The magnification adjusting part  28  is an adjusting part that adjusts the magnification of the optical sight  10 . The diopter adjusting part  30  is an adjusting part that adjusts the diopter with respect to the reticle mounted on the optical sight  10 . Each of these adjustment configurations has, for example, the same or similar configuration as known adjustment configurations according to the purpose of adjustment. Further, at least a part among these adjusting parts may also have a configuration having the same or similar lock mechanism as the lock mechanism of the impact position adjusting part  22  to be described below. According to the present example, it is possible to appropriately provide an optical sight  10  capable of various adjustments associated with optical characteristics and aiming, for example. 
     Next, the features of the impact position adjusting part  22  will be described in more detail.  FIG. 2( a ) ,  FIG. 2( b ) ,  FIG. 3( a ) , and  FIG. 3( b )  are views showing the configuration and function of the optical sight  10 .  FIG. 2( a )  and  FIG. 2( b )  are views showing components constituting a main part of the impact position adjusting part  22 .  FIG. 2( a )  and  FIG. 2( b )  are a perspective view and a cross-sectional view showing an example of components constituting a main part of the impact position adjusting part  22 .  FIG. 3( a )  and  FIG. 3( b )  are views showing the lock mechanism of the impact position adjusting part  22 .  FIG. 3( a )  is a cross-sectional view showing the impact position adjusting part  22  in an unlocked state, i.e., a state in which the lock mechanism is not locked.  FIG. 3( b )  is a cross-sectional view showing the impact position adjusting part  22  in a locked state, i.e., a state in which the lock mechanism is locked. Further, as shown in the figures, in the present example, each of the impact position adjusting parts  22  has a rotating part  102 , an upper cap  104 , a fixed tubular part  106 , a shaft part  108 , and a click ball part  110 . Further, the rotating part  102  has a rotating operation part  122  and a rotating tubular part  124 . Among these configurations, the fixed tubular part  106  is an example of a first tubular part in a tubular shape in which outer peripheral recesses-projections are formed on at least a part of the outer peripheral surface. The rotating tubular part  124  is an example of a second tubular part in a tubular shape in which inner peripheral recesses-projections having a shape that engages with the outer peripheral recesses-projections of the first tubular part are formed on at least a part of the inner peripheral surface. 
     The rotating part  102  is a portion that directly rotates according to the user&#39;s operation, and has a rotating operation part  122  and a rotating tubular part  124  as described above. Further, in the present example, each of the rotating operation part  122  and the rotating tubular part  124  forms a part of the rotating part  102  formed as one component. In this case, the formation of the rotating part  102  as one component may refer to, for example, forming portions functioning as the rotating operation part  122  and the rotating tubular part  124  to be continuously and integrally connected instead of being assembled using multiple individually processed components. Further, more specifically, in the present example, the rotating part  102  having the rotating operation part  122  and the rotating tubular part  124  is formed by processing one metal material. In a modified example of the configuration of the rotating part  102 , for example, the rotating operation part  122  and the rotating tubular part  124  may be respectively composed of separate components. In this case, the rotating part  102  may be, for example, a member (e.g., a two-body object) composed of multiple components. 
     Further, in this case, among the portions constituting the rotating part  102 , the rotating operation part  122  may be, for example, a portion that realizes a rotating function according to the user&#39;s operation by receiving an operation by the user. Further, the rotating tubular part  124  may be, for example, a portion that rotates together with the rotating operation part  122  by fixing the position with respect to the rotating operation part  122 . Further, for example, the axial direction of the rotating tubular part  124  may be made parallel to the rotation axis of the rotating operation part  122  and the position of the rotating tubular part  124  may be fixed with respect to the rotating operation part  122  so as to rotate together with the rotating operation part  122 . In this case, the rotation axis of the rotating operation part  122  may be, for example, the rotation axis in the case where the rotating operation part  122  rotates according to the user&#39;s operation when adjusting the impact position. Further, the axial direction of the rotating tubular part  124  may be, for example, a direction corresponding to the axial direction of a cylinder in the case where the shape of the rotating tubular part  124  is approximated by a cylinder. 
     Further, in the present example, the inner peripheral surface of the rotating tubular part  124  is formed with inner peripheral recesses-projections  202 , which are recesses-projections composed of projections and recesses extending in a direction parallel to the axial direction of the rotating tubular part  124  and alternately arranged in the circumferential direction of the inner peripheral surface. In this case, for example, the tubular portion of the rotating part  102  including at least the portion formed with the inner peripheral recesses-projections  202  may form the portion corresponding to the rotating tubular part  124 . Further, the portion of the rotating part  102  other than the rotating tubular part  124  may form the portion corresponding to the rotating operation part  122 . Further, in the present example, the inner peripheral recesses-projections  202  are recesses-projections used to realize the lock mechanism of the impact position adjusting part  22 , and are recesses-projections having a shape that engages with outer peripheral recesses-projections  204  of the fixed tubular part  106  to be described in detail later. Further, the engagement between the inner peripheral recesses-projections  202  and the outer peripheral recesses-projections  204  may refer to, for example, fitting the projections of the inner peripheral recesses-projections  202  into the recesses of the outer peripheral recesses-projections  204 , and fitting the projections of the outer peripheral recesses-projections  204  into the recesses of the inner peripheral recesses-projections  202 . Further, in a state in which the inner peripheral recesses-projections  202  and the outer peripheral recesses-projections  204  are engaged with each other, for example, the inner peripheral recesses-projections  202  and the outer peripheral recesses-projections  204  may mesh with each other so that the rotating tubular part  124  is prohibited from rotating in the circumferential direction of the rotating tubular part  124  relative to the fixed tubular part  106 . 
     Further, the rotating part  102  is formed with a hole into which the shaft part  108  is inserted at the position of the rotation axis of the rotating operation part  122 . In the present example, this hole is a hole that is connected to the space inside the rotating tubular part  124  and penetrates to the upper surface of the rotating part  102 . The upper cap  104  is a cap member that closes this hole from the upper surface side of the rotating part  102  so that the rotating part  102  does not come off. The fixed tubular part  106  is a tubular part that realizes the lock mechanism of the impact position adjusting part  22  together with the rotating tubular part  124  of the rotating part  102 . In the present example, as shown in  FIG. 3( a )  and  FIG. 3( b ) , the fixed tubular part  106  is axially aligned with the rotating tubular part  124  and is arranged at a position fixed to the housing  14  (see  FIG. 1 ) of the optical sight  10 . For example, the fixed tubular part  106  may be fixed to the housing  14  so as not to rotate together with the rotating part  102 . Further, as described above, in the present example, the outer peripheral surface of the fixed tubular part  106  is formed with the outer peripheral recesses-projections  204 . Further, the inner peripheral surface of the fixed tubular part  106  is formed with recesses-projections against which the steel ball of the click ball part  110  is pressed. The locking function realized by the rotating tubular part  124  and the fixed tubular part  106  will be described in more detail later. 
     The shaft part  108  is a shaft-shaped member that extends in a direction parallel to the rotation axis at the position of the rotation axis of the rotating operation part  122 , and rotates together with the rotating operation part  122  by being fixed to the rotating operation part  122  by a known method. Further, in the present example, by displacing the optical axis direction of the optical system  12  (see  FIG. 1 ) with respect to the housing  14  of the optical sight  10  according to the amount of rotation, the shaft part  108  performs the operation of adjustment with the impact position adjusting part  22 . Further, in the present example, the shaft part  108  is an example of an adjusting mechanism of the operation adjusting part. In this case, the adjusting mechanism may be, for example, a mechanism that performs adjustment associated with the function of the optical sight  10  by moving a part of the optical sight  10  according to the amount of rotation of the rotating operation part  122 . Further, this adjusting mechanism may also be a mechanism that performs adjustment associated with the function of the optical sight  10  together with another configuration by linking with the another configuration. In this case, the portion combining the shaft part  108  and the another configuration linking with the shaft part  108  may be also an example of the adjusting mechanism. The click ball part  110  is a configuration for generating a click feeling according to the amount of rotation when the rotating operation part  122  is rotated. In the present example, the click ball part  110  has a steel ball, a holding member, and a spring, and the holding member holding the steel ball is urged by the spring housed in a hole formed in the shaft part  108  so that the steel ball is pressed against the recesses-projections of the inner peripheral surface of the fixed tubular part  106 . 
     Here, the characteristics of the inner peripheral recesses-projections  202  of the rotating tubular part  124  and the outer peripheral recesses-projections  204  of the fixed tubular part  106 , and the locking function realized by the rotating tubular part  124  and the fixed tubular part  106  will be described in more detail. In the present example, the inner peripheral recesses-projections  202  and the outer peripheral recesses-projections  204  may be, for example, serration-shaped recesses-projections that engage with each other. Further, the shapes of the inner peripheral recesses-projections  202  and the outer peripheral recesses-projections  204  may also be, for example, straight knurled recesses-projections, splined recesses-projections, serrated recesses-projections, or the like. Further, in the present example, the inner peripheral recesses-projections  202  of the rotating tubular part  124  are recesses-projections of which projections and recesses extending in a direction parallel to the axial direction of the rotating tubular part  124  are alternately arranged in the circumferential direction of the inner peripheral surface of the rotating tubular part  124 . The projections and the recesses constituting the inner peripheral recesses-projections  202  are arranged in the circumferential direction of the inner peripheral surface of the rotating tubular part  124  at a constant cycle. Further, each projection of the inner peripheral recesses-projections  202  extends in the axial direction of the rotating tubular part  124  with a constant width in the circumferential direction of the inner peripheral surface of the rotating tubular part  124 . Further, each recess of the inner peripheral recesses-projections  202  also extends in the axial direction of the rotating tubular part  124  with a constant width in the circumferential direction of the inner peripheral surface of the rotating tubular part  124 . In this case, the width of the recess in the circumferential direction may be different from the width of the projection. Further, the width of the projection and the width of the recess may differ depending on the position in the height direction (depth direction) orthogonal to the inner peripheral surface of the rotating tubular part  124 . Specifically, the recess of the inner peripheral recesses-projections  202  may be formed as, for example, a recess having a V-shaped cross section (a recess in the shape of a V-shaped groove). In this case, the widths of the recess and the projection may change depending on the position in the height direction according to the shape of the recess having a V-shaped cross section. 
     Further, in the present example, the outer peripheral recesses-projections  204  of the fixed tubular part  106  are recesses-projections of which projections and recesses extending in a direction parallel to the axial direction of the fixed tubular part  106  are alternately arranged in the circumferential direction of the outer peripheral surface. The projections and the recesses constituting the outer peripheral recesses-projections  204  are arranged in the circumferential direction of the outer peripheral surface of the fixed tubular part  106  at a constant cycle. Further, in the present example, except in the vicinity of an end part on a side close to the rotating tubular part  124 , each projection of the outer peripheral recesses-projections  204  extends in the axial direction of the fixed tubular part  106  with a constant width in the circumferential direction of the outer peripheral surface of the fixed tubular part  106 . In this case, the end part on the side close to the rotating tubular part  124  may be, for example, an end part close to the rotating tubular part  124  in the unlocked state shown in  FIG. 3( a ) . Further, for example, at least at a part other than the vicinity of the end part on the side close to the rotating tubular part  124 , such projections of the outer peripheral recesses-projections  204  may be arranged at a constant cycle in the circumferential direction with a constant width in the circumferential direction of the fixed tubular part  106 . Further, except in the vicinity of the end part on the side close to the rotating tubular part  124 , each recess of the outer peripheral recesses-projections  204  also extends in the axial direction of the fixed tubular part  106  with a constant width in the circumferential direction of the outer peripheral surface of the fixed tubular part  106 . Further, in the outer peripheral recesses-projections  204 , the width of the recess in the circumferential direction may be different from the width of the projection. Further, the width of the projection and the width of the recess may differ depending on the position in the height direction (depth direction) orthogonal to the outer peripheral surface of the fixed tubular part  106 . Specifically, the recess of the outer peripheral recesses-projections  204  may be formed as, for example, a groove having a V-shaped cross section. In this case, the widths of the recess and the projection may change depending on the position in the height direction according to the shape of the recess having a V-shaped cross section. 
     Further, in the present example, the width of the projection of the outer peripheral recesses-projections  204  in the vicinity of the end part on the side close to the rotating tubular part  124  gradually decreases toward the end part. In this case, the gradual decrease in the width of the projection toward the end part may mean, for example, that the width is gradually narrow as it approaches the end part, when the width of the projection is viewed with the position in the height direction being constant. Further, in the present example, the width of the recess gradually increases toward the end part according to the change in the width of the projection. In this case, the gradual increase in the width of the recess toward the end part may mean, for example, that the width gradually increases as it approaches the end part, when the width of the recess is viewed with the position in the height direction (depth direction) being constant. Further, for example, the width of the recess in the circumferential direction of the outer peripheral recesses-projections  204  may also gradually increase toward the end part as the width of the adjacent projections decreases. The shapes of the projection and the recess of the outer peripheral recesses-projections  204  will be described in more detail later. 
     Further, as can be understood from the comparison between the unlocked state and the locked state shown in  FIG. 3( a )  and  FIG. 3( b ) , in the present example, the rotating part  102 , which is the portion including the rotating operation part  122  and the rotating tubular part  124 , may move forward and backward in a direction parallel to the axial direction of the rotating tubular part  124 . In this case, for example, the rotating operation part  122  may move together with the rotating tubular part  124  according to the user&#39;s operation. Further, in the present example, according to the user&#39;s operation, the rotating operation part  122  at least moves to a rotatable position at which the impact position adjusting part  22  is in the unlocked state and a rotation prohibited position at which the impact position adjusting part  22  is in the locked state. In this case, the rotatable position may be, for example, a position at which rotation of the rotating operation part  122  is made possible by separation between the inner peripheral recesses-projections  202  of the rotating tubular part  124  and the outer peripheral recesses-projections  204  of the fixed tubular part  106 . 
     Further, the separation between the inner peripheral recesses-projections  202  and the outer peripheral recesses-projections  204  may refer to, for example, coming into a position at which the inner peripheral recesses-projections  202  and the outer peripheral recesses-projections  204  are not engaged with each other, as shown in the figure. Further, the rotation prohibited position may be, for example, a position at which rotation of the rotating operation part  122  is prohibited by engagement between the inner peripheral recesses-projections  202  and the outer peripheral recesses-projections  204 . The prohibition of the rotation of the rotating operation part  122  may refer to, for example, prohibiting the rotating operation part  122  and the rotating tubular part  124  from rotating in the circumferential direction of the rotating tubular part  124  relative to the fixed tubular part  106 . The prohibition of rotation may mean, for example, that depending on the precision required for the locking function, rotation is substantially prohibited so that it can be regarded as locked. 
     According to the present example, for example, by pushing the rotating operation part  122  at the position of the unlocked state, the state of the impact position adjusting part  22  can be changed to the locked state. Further, by pulling back the rotating operation part  122  in the locked state, the locked state of the impact position adjusting part  22  can be appropriately released. Further, in the present example, as described above, by configuring the shape of the projection of the outer peripheral recesses-projections  204  of the fixed tubular part  106  to have a width that gradually decreases toward the end part, for example, the impact position adjusting part  22  can be locked more appropriately without causing misrecognition to the user. Therefore, this point will be described in more detail below. 
     First, for convenience of illustration, an example of misrecognition that occurs at the time of locking the impact position adjusting part  22  will be described.  FIG. 4( a )  and  FIG. 4( b )  are views showing misrecognition that occurs at the time of locking the impact position adjusting part  22 , and shows an example of misrecognition that occurs in the case of using an impact position adjusting part having a configuration partially different from the impact position adjusting part  22  of the present example.  FIG. 4( a )  shows an example of a state in which locking is correctly performed.  FIG. 4( b )  shows an example of misrecognition that occurs at the time of locking. Specifically, in the case shown in  FIG. 4( a )  and  FIG. 4( b ) , in place of the fixed tubular part  106  (see  FIG. 2( a )  and  FIG. 2( b ) ) described above, a fixed tubular part  606  in which only the shape of the outer peripheral recesses-projections is different from the fixed tubular part  106  is used. On the outer peripheral surface of the fixed tubular part  606 , outer peripheral recesses-projections  612  are formed by projections  622  and recesses  624  in place of the outer peripheral recesses-projections of the fixed tubular part  106 . Further, the projection  622  and the recess  624  of the outer peripheral recesses-projections  612  of the fixed tubular part  606  have a width in the circumferential direction of the outer peripheral surface of the fixed tubular part  606  that is constant over the axial direction of the fixed tubular part  606 . 
     Similarly, when the fixed tubular part  606  having such a configuration is used, for example, as shown in  FIG. 4( a ) , by engaging the inner peripheral recesses-projections  202  of the rotating tubular part  124  with the outer peripheral recesses-projections  612  of the fixed tubular part  606 , the impact position adjusting part can be brought into the locked state. However, in this case, depending on the method of contact between the rotating tubular part  124  and the fixed tubular part  606 , in the operation of pushing the rotating operation part  122  (see  FIG. 2( a )  and  FIG. 2( b ) ) of the rotating part  102  into the locked state, for example, as shown by a halfway stop state in  FIG. 4( b ) , before the inner peripheral recesses-projections  202  of the rotating tubular part  124  and the outer peripheral recesses-projections  612  of the fixed tubular part  606  are appropriately engaged, the user may be given an impression that the movement of the rotating operation part  122  (movement of the rotating tubular part  124 ) has been completed. Specifically, in this case, for example, in the operation of pushing the rotating operation part  122  by the user, at the time point when the rotating tubular part  124  and the fixed tubular part  606  come into contact with each other, since a projection  212  of the inner peripheral recesses-projections  202  of the rotating tubular part  124  and the projection  622  of the outer peripheral recesses-projections  612  of the fixed tubular part  606  collide with each other, the user may be given an impression that the push has been completed. As a result, the user may be given an erroneous impression that it is in the locked state. 
     In contrast, in the present example, as shown in  FIG. 5 , for example, by configuring the shape of a projection  222  of the outer peripheral recesses-projections  204  of the fixed tubular part  106  to have a width that gradually decreases toward the end part, it is less likely to give such an erroneous impression to the user.  FIG. 5  is a simplified view showing the operation at the time of locking the impact position adjusting part  22  in the present example. 
     In the present example, as can be understood from the shown configuration, with the width of the projection  222  of the outer peripheral recesses-projections  204  in the vicinity of the end part on one side of the fixed tubular part  106  gradually decreasing toward the end part, in the operation of moving the rotating operation part  122  (see  FIG. 2( a )  and  FIG. 2( b ) ) from the rotatable position to the rotation prohibited position, the outer peripheral recesses-projections  204  of the fixed tubular part  106  and the inner peripheral recesses-projections  202  of the rotating tubular part  124  can be more naturally engaged with each other. Specifically, in this case, by using the projection  222  in the shape having a width gradually decreasing toward the end part, for example, it is possible to reduce the probability that the tip of the projection  222  of the outer peripheral recesses-projections  204  of the fixed tubular part  106  and the projection  212  of the inner peripheral recesses-projections  202  of the rotating tubular part  124  come into contact with each other. Further, in this case, even if the tip of the projection  222  of the outer peripheral recesses-projections  204  and the projection  212  of the inner peripheral recesses-projections  202  are temporarily in contact with each other, with the width of the projection  222  being narrow in the vicinity of the end part, the tip of the projection  222  of the outer peripheral recesses-projections  204  may easily escape to the position of a recess  214  of the inner peripheral recesses-projections  202 , for example, due to the influence of position fluctuations caused by the operation of pushing the rotating operation part  122 . Further, in this case, after the tip of the projection  222  of the outer peripheral recesses-projections  204  moves to the position of the recess  214  of the inner peripheral recesses-projections  202 , for example, as shown on the lower left side of  FIG. 5 , the movement of the rotating tubular part  124  can be guided by the shape of the projection  222  of the outer peripheral recesses-projections  204  in the vicinity of the end part. In this case, the guidance of the movement of the rotating tubular part  124  by the shape of the projection  222  in the vicinity of the end part may refer to, for example, moving the rotating tubular part  124  to a desired position by moving the projection  212  of the inner peripheral recesses-projections  202  of the rotating tubular part  124  along the side surface of the projection  222  of the outer peripheral recesses-projections  204  of the fixed tubular part  106 . Further, the inventors of the present application have confirmed the above effects by actually creating the rotating tubular part  124  and the fixed tubular part  106  having the above shapes. According to the present example, for example, when moving the rotating operation part  122  from the rotatable position to the rotation prohibited position, the inner peripheral recesses-projections  202  of the rotating tubular part  124  and the outer peripheral recesses-projections  204  of the fixed tubular part  106  can be appropriately and naturally engaged with each other. Accordingly, for example, it is possible to appropriately prevent giving the user an impression of being in the locked state while it is actually in the unlocked state. 
     Further, in such an operation, for example, when moving the rotating operation part  122  from the rotatable position to the rotation prohibited position, the movement of the rotating tubular part  124  may be guided by the projection of which the width gradually decreases toward the end part in the outer peripheral recesses-projections  204  of the fixed tubular part  106  so that the outer peripheral recesses-projections  204  and the inner peripheral recesses-projections  202  of the rotating tubular part  124  are engaged with each other. Further, in the present example, the vicinity of the end part of the fixed tubular part  106 , which is the range in which the widths of the projection  222  and the recess  224  at the outer peripheral recesses-projections  204  of the fixed tubular part  106  are gradually changed, may be, for example, a range of width that can guide the movement of the rotating tubular part  124 . Further, the vicinity of the end part may also be, for example, a range of a part of the fixed tubular part  106  with which such an effect can be obtained. Further, in practice, the range in which the widths of the projection  222  and the recess  224  are gradually changed in the outer peripheral recesses-projections  204  may be, for example, about 5% or less (e.g., about 0.1% to 5%) of the length of the projection  222  and the recess  224  in the axial direction of the fixed tubular part  106 . Further, this range is exemplarily a range of about 3% or less. 
     Next, a method of manufacturing the optical sight  10  will be described. At the time of manufacturing the optical sight  10 , for example, the optical sight  10  is manufactured by manufacturing and assembling the components corresponding to the configurations of the optical sight  10  shown in  FIG. 1 . Further, each component may also be manufactured by combining multiple components as needed. For example, regarding the impact position adjusting part  22 , the portion corresponding to the impact position adjusting part  22  is manufactured by manufacturing and assembling the components of the impact position adjusting part  22  shown in  FIG. 2( a ) ,  FIG. 2( b ) ,  FIG. 3( a ) , and  FIG. 3( b ) . Further, as can be understood from the above description, for example, the impact position adjusting part  22  of the present example may use a plurality of tubular parts such as the fixed tubular part  106  and the rotating tubular part  124 . Therefore, the impact position adjusting part  22  and the optical sight  10  may be an example of a tubular part-using product, i.e., a product using a plurality of tubular parts, for example. Further, in this case, the step of creating the fixed tubular part  106  of the impact position adjusting part  22  may be an example of a first tubular part creating step in which the first tubular part is created, for example. The step of creating the rotating part  102  having the rotating tubular part  124  may be an example of a second tubular part creating step in which the second tubular part is created, for example. 
     Further, in the step of creating the rotating part  102  and the step of creating the fixed tubular part  106 , the inner peripheral recesses-projections  202  of the rotating tubular part  124  and the outer peripheral recesses-projections  204  of the fixed tubular part  106  may be formed by using a cutting tool having a cutting blade. In this case, a known bit (cutting bit) or the like may be suitably used as the cutting tool. Further, specifically, the inner peripheral recesses-projections  202  and the outer peripheral recesses-projections  204  may be formed by using a known machine tool such as, for example, a known compound processing machine (NC compound machine). 
     Further, as described above, in the present example, the projection  222  of the outer peripheral recesses-projections  204  of the fixed tubular part  106  has a shape of which the width gradually decreases toward the end part. Then, in this case, when forming the outer peripheral recesses-projections  204 , the bit may be moved relative to the fixed tubular part  106  being processed, for example, by an operation described below with reference to  FIG. 6( a ) ,  FIG. 6( b ) , and  FIG. 7 , so that a recess  224  having a shape corresponding to such a projection  222  is formed. 
       FIG. 6( a ) ,  FIG. 6( b ) , and  FIG. 7  are views showing an example of an operation of forming the outer peripheral recesses-projections in the step of forming the fixed tubular part  106 .  FIG. 6( a )  and  FIG. 6( b )  are views showing an outline of an operation of forming a recess of the outer peripheral recesses-projections using a bit  502 .  FIG. 6( a )  and  FIG. 6( b )  are views showing the positional relationship between the fixed tubular part  106  and the bit  502  at the time of forming the outer peripheral recesses-projections. Further, in  FIG. 6( a )  and  FIG. 6( b ) , for convenience of illustration, the fixed tubular part  106  before the outer peripheral recesses-projections are formed is shown in a state in which the outer peripheral recesses-projections are formed. 
     As can be understood from the illustration in the figure, in the present example, using the bit  502  having a blade for forming a recess in the shape of a V-shaped groove, by pressing the blade of the bit  502  against the side surface of the fixed tubular part  106  and moving the bit  502  relative to the fixed tubular part  106 , a groove forming the recess of the outer peripheral recesses-projections is formed on the outer peripheral surface of the fixed tubular part  106 . In this case, the recess in the shape of a V-shaped groove may be, for example, a groove-shaped recess of which the width gradually increases as the distance from the bottom increases. Further, “the recess of the outer peripheral recesses-projections being in the shape of a V-shaped groove” may mean, for example, that a cross section of the recess along a plane orthogonal to the axial direction of the fixed tubular part  106  has a shape of which the width gradually increases as the distance from the bottom increases. Further, when the bit  502  having the shown configuration is used, the width of the recess may linearly increase according to, for example, the height from the bottom surface. 
     Further, the blade of the bit  502  having the shown configuration may be, for example, a blade having a shape that forms a recess in the shape of a V-shaped groove by moving relative to a work piece while being pressed against the work piece. In this case, for example, if the depth at which the blade of the bit  502  is pressed against the outer peripheral surface of the fixed tubular part  106  is kept constant and the bit  502  is moved relative to the fixed tubular part  106  in the axial direction of the fixed tubular part  106 , a recess having a constant width is formed. The width of the recess being constant may mean, for example, that the width of the recess at the same depth in the depth direction of the recess is constant. Further, in this case, for example, the width of the recess may become wider as the depth at which the blade of the bit  502  is pressed against the outer peripheral surface of the fixed tubular part  106  increases. 
     Therefore, at the time of forming the outer peripheral recesses-projections, for example, at the portion other than the vicinity of the end part of the fixed tubular part  106  on the side close to the rotating part  102  (the side close to the rotating tubular part  124 ), a recess of a constant width may be formed by keeping the depth at which the blade of the bit  502  is pressed constant and moving the bit  502  relative to the fixed tubular part  106 , for example, in a cutting direction shown in  FIG. 6( a ) . Further, in this case, the widths of the recess and the projection may be gradually changed, for example, by forming the recess of the outer peripheral recesses-projections while gradually changing the depth at which the blade of the bit  502  is pressed against the vicinity of the end part of the fixed tubular part  106  on the side close to the rotating part  102 , as shown in  FIG. 7 . 
       FIG. 7  is a view showing an operation of forming the outer peripheral recesses-projections of the fixed tubular part  106 . In the present example, when forming the outer peripheral recesses-projections of the fixed tubular part  106 , the cutting process for forming each recess of the outer peripheral recesses-projections is started from the side of the end part of the fixed tubular part  106  on the side close to the rotating part  102 . In this case, for example, as shown by a cutting direction in the left view of  FIG. 7 , the recess of the outer peripheral recesses-projections is formed in the vicinity of one end part of the fixed tubular part  106  by moving the bit  502  relative to the fixed tubular part  106  in a direction non-parallel to the axial direction of the fixed tubular part  106 . Specifically, in this case, for example, a part of the recess is formed by cutting a groove forming the recess toward an opposite side of the fixed tubular part  106  while gradually increasing the distance from the central axis of the fixed tubular part  106  to the blade of the bit  502 . For example, the cutting direction in this operation may be a direction of which an inclination with respect to the axial direction of the fixed tubular part  106  is about 20° to 70°. This inclination is exemplarily about 30° to 60°. Further, in such an operation, for example, a part of the recess of the outer peripheral recesses-projections of the fixed tubular part  106  may be formed in the following manner: with the blade of the bit  502  pressed against the fixed tubular part  106  to be processed, moving the blade of the bit  502  relative to the fixed tubular part  106  in a direction gradually away from the central axis of the fixed tubular part  106  while advancing in a direction parallel to the axial direction of the fixed tubular part  106 . With this configuration, for example, the width of the recess can be gradually increased toward the end part in the vicinity of one end part of the fixed tubular part  106 . 
     Further, in the present example, after the formation of the portion at which the width of the recess gradually changes is completed, the bit  502  is moved relative to the fixed tubular part  106  in a direction parallel to the axial direction of the fixed tubular part  106  while the distance from the central axis of the fixed tubular part  106  to the blade of the bit  502  is kept constant. Accordingly, a portion of the recess having a constant width is formed on the outer peripheral surface of the fixed tubular part  106 . In this case, for example, as shown by an arrow in the central view of  FIG. 7 , the cutting direction is changed at a predetermined timing so that the cutting direction is parallel to the axial direction of the fixed tubular part  106 , and as shown in the right view of  FIG. 7 , the recess at the portion other than the vicinity of one end part of the fixed tubular part  106  is formed. Further, in such an operation, for example, with the blade of the bit  502  pressed against the fixed tubular part  106 , by keeping the distance from the central axis of the fixed tubular part  106  constant and moving the blade of the bit  502  relative to the fixed tubular part  106 , another part of the recess of the outer peripheral recesses-projections may also be formed. Further, in the present example, the outer peripheral recesses-projections are formed by sequentially rotating the fixed tubular part  106  according to the cycle of the recesses-projections set in advance and forming the recess at each rotation position. Further, in this case, since the portion sandwiched between adjacent recesses forms a projection, the width of the projection gradually decreases toward the end part. Therefore, with this configuration, in the step of creating the fixed tubular part  106 , it is possible to appropriately form the outer peripheral recesses-projections having the projection of which the width gradually decreases toward the end part. 
     Further, as can be understood from the above description, in the present example, the portion of the recess at which the width gradually changes and the portion at which the width is constant may be continuously formed by a series of operations while maintaining the state in which the blade of the bit  502  is in contact with the outer peripheral surface of the fixed tubular part  106 , for example. In this regard, if only gradually changing the widths of the recess and the projection is considered, for example, the bit  502  used for processing the vicinity of the end part and the bit  502  used for processing the portion at which the width of the recess is constant may be different from each other. However, in that case, it is necessary to change the bit  502  in the operation of forming one recess, and a position deviation is likely to occur between the vicinity of the end part and the another portion. Specifically, in the fixed tubular part  106  of the present example, for example, recesses may be formed at positions dividing the circumference along the outer peripheral surface into about 100 equal parts. Then, in that case, if an attempt is made to form the recess using multiple bits  502 , alignment becomes difficult and the above deviation is likely to occur. Further, if an attempt is made to align with high precision, the cost and time required for processing may increase significantly. In contrast, according to the present example, by forming the recess having the above shape with one bit  502 , it is possible to appropriately process the outer peripheral recesses-projections with high precision. 
     Further, as described above, in the present example, the blade of the bit  502  is inserted into the fixed tubular part  106  from the side of the end part on the side where the widths of the projection and the recess are gradually changed. With this configuration, for example, it is possible to more easily and appropriately process the outer peripheral recesses-projections on the fixed tubular part  106 . Further, depending on the shape of the fixed tubular part  106 , for example, the blade of the bit  502  may also be inserted into the fixed tubular part  106  from the side of the end part opposite to the side where the widths of the projection and the recess are gradually changed. In that case, for example, after processing the portion at which the width of the recess is constant, by gradually changing the depth at which the blade of the bit  502  is pressed, it is also possible to gradually decrease the width of the projection and gradually increase the width of the recess toward the end part. 
     Next, the shapes of the projection and the recess of the outer peripheral recesses-projections formed as described above will be described in more detail.  FIG. 8  is a view showing an example of the configuration of the fixed tubular part  606  formed with the outer peripheral recesses-projections  612  having a shape different from that of the present example, and shows an example of the configuration of the fixed tubular part  606  together with the shaft part  108  in the case where the outer peripheral recesses-projections  612  having the projection  622  and the recess  624  as described above with reference to  FIG. 4( a )  and  FIG. 4( b )  are formed. In  FIG. 8 , the upper view is a perspective view of the entire fixed tubular part  606  and a portion A. The lower view is a side view of the entire fixed tubular part  606  and a portion B. In this case, the portion A of the fixed tubular part  606  is the portion indicated by a circle A in the perspective view of the entire fixed tubular part  606 . The portion B of the fixed tubular part  606  is the portion indicated by a circle B in the side view of the entire fixed tubular part  606 . The fixed tubular part  606  shown in  FIG. 8  may have, for example, a configuration in which the entire recess  624  is formed by keeping the distance from the central axis to the blade of the bit constant without performing the operation of gradually changing the distance from the central axis of the fixed tubular part  606  to the blade of the bit, when forming the recess  624  of the outer peripheral recesses-projections  612 . In this case, as can be understood from the shown configuration, the depth of the recess  624  may be constant over the entire recess  624 . 
     In contrast, in the present example, the shapes of the projection  222  and the recess  224  of the outer peripheral recesses-projections  204  are, for example, the shapes as shown in  FIG. 9 .  FIG. 9  is a view showing an example of the configuration of the fixed tubular part  106  in the present example, and shows an example of the configuration of the fixed tubular part  106  together with the shaft part  108  in the case where the outer peripheral recesses-projections  204  as described above with reference to  FIG. 7  are formed, for example. In  FIG. 9 , the upper view is a perspective view of the entire fixed tubular part  106  and a portion A. The lower view is a side view of the entire fixed tubular part  106  and a portion B. 
     As can be understood from the comparison with the fixed tubular part  606  shown in  FIG. 8 , in the fixed tubular part  106  of the present example, the shapes of the outer peripheral recesses-projections  204  and the projection  222  of the outer peripheral recesses-projections  204  in the vicinity of the end part of the fixed tubular part  106  on the side close to the rotating tubular part  124  (see  FIG. 3( a )  and  FIG. 3( b ) ) are different from those shown in  FIG. 8 . In this case, the side close to the rotating tubular part  124  is the side close to the rotating tubular part  124  in the state in which the impact position adjusting part  22  has been assembled. Further, specifically, as described above, in the present example, in the vicinity of the end part of the fixed tubular part  106 , the width of the projection  222  gradually decreases and the depth and the width of the recess  224  gradually increase toward the end part. In this case, the depth of the recess  224  may be, for example, a depth based on the height of the outer peripheral surface of the fixed tubular part  106  before the recess  224  is formed. 
     Here, in the fixed tubular part  606  shown in  FIG. 8  and the fixed tubular part  106  shown in  FIG. 9 , a chamfering process is performed on a portion at which the outer peripheral surface and the end surface are connected in the vicinity of the end part on the side close to the rotating part  102 . In this case, the depth of the recess (recess  624  or recess  224 ) in the vicinity of the end part may be, for example, the depth based on the position at which the outer peripheral surface is located as in the case where the chamfering process is not performed. Further, in  FIG. 8  and FIG.  9 , the shapes of the outer peripheral recesses-projections  612  and the outer peripheral recesses-projections  204  are difficult to read from the figures due to the influence of the chamfering process. Therefore, in the following, with reference to  FIG. 10( a ) ,  FIG. 10( b ) ,  FIG. 10( c ) ,  FIG. 11( a ) ,  FIG. 11( b ) , and  FIG. 11( c ) , the shapes of the outer peripheral recesses-projections  612  of the fixed tubular part  606  and the outer peripheral recesses-projections  204  of the fixed tubular part  106  shown in  FIG. 8  and  FIG. 9  will be described in more detail. 
       FIG. 10( a ) ,  FIG. 10( b ) , and  FIG. 10( c )  are simplified views showing the shapes of the projection  622  and the recess  624  of the outer peripheral recesses-projections  612  (see  FIG. 8 ) of the fixed tubular part  606  shown in  FIG. 8 .  FIG. 10( a )  is a top view showing the projection  622  and the recess  624  as viewed from the normal direction of the outer peripheral surface of the fixed tubular part  606 .  FIG. 10( b )  and  FIG. 10( c )  are cross-sectional views at positions of line AA and line BB shown in dot-dashed lines in  FIG. 10( a ) .  FIG. 11( a ) ,  FIG. 11( b ) , and  FIG. 11( c )  are simplified views showing the shapes of the projection  222  and the recess  224  of the outer peripheral recesses-projections  204  (see  FIG. 9 ) of the fixed tubular part  106  shown in  FIG. 9 .  FIG. 11( a )  is a top view showing the projection  222  and the recess  224  as viewed from the normal direction of the outer peripheral surface of the fixed tubular part  106 .  FIG. 11( b )  and  FIG. 11( c )  are cross-sectional views at positions of line AA and line BB shown in in dot-dashed lines in  FIG. 11( a ) . 
     In  FIG. 10( a ) ,  FIG. 10( b ) ,  FIG. 10( c ) ,  FIG. 11( a ) ,  FIG. 11( b ) , and  FIG. 11( c ) , for convenience of illustration, the shapes of the projection  622 , the recess  624 , the projection  222 , the recess  224 , and the like are shown with various simplifications. Specifically, in  FIG. 10( a ) ,  FIG. 10( b ) ,  FIG. 10( c ) ,  FIG. 11( a ) ,  FIG. 11( b ) , and  FIG. 11( c ) , the scale in each direction is appropriately changed so that the characteristics of each part can be easily understood. Further, in these figures, considering that the outer peripheral surfaces of the fixed tubular part  606  and the fixed tubular part  106  may be regarded as being substantially flat in a narrow range, a part of the fixed tubular part  606  and the fixed tubular part  106  is shown excluding the influence of the curvature of the outer peripheral surface. Further, in order to prevent the shape of each part from becoming difficult to understand due to the influence of the chamfering process, the shape of each part as in the case where the chamfering process is omitted is shown in the figures. When the chamfering process is actually performed, the position shown by a broken line  702  in  FIG. 10( b )  and  FIG. 11( b )  is the position of the chamfering process. 
     As can be understood from the configuration shown in  FIG. 10( a ) ,  FIG. 10( b ) , and  FIG. 10( c ) , in the fixed tubular part  606  shown in  FIG. 8 , the depth of the recess  624  is constant over the entire recess  624 , as shown by a depth d in  FIG. 10( b ) . Then, in this case, the width of the recess  624  is also constant over the entire recess  624  at each position in the depth direction. As a result, the width of the projection  622 , which is the portion between the recesses  624 , is also constant over the entire projection  622 . 
     In contrast, in the case of the fixed tubular part  106  of the present example, for example, as shown in  FIG. 11( b ) , in the vicinity of the end part on one side close to the rotating tubular part  124  (see  FIG. 3( a )  and  FIG. 3( b ) ) in the impact position adjusting part  22  (see  FIG. 3( a )  and  FIG. 3( b ) ), the depth of the recess  224  gradually increases toward the end part. Further, as described above, in the present example, the recess  224  is a recess in the shape of a V-shaped groove of which the width gradually increases as the distance from the bottom increases. Then, in this case, with the position of the bottom of the recess  224  gradually becoming deeper toward the end part in the vicinity of the end part, the width of the recess  224  also gradually increases toward the end part. Specifically, in this case, at each position in the depth direction, the width of the recess  224  gradually increases toward the end part. As a result, the width of the projection  222 , which is the portion between the recesses  224 , gradually decreases toward the end part as shown in  FIG. 11( a ) , for example. By using the fixed tubular part  106  formed with the projection  222  having such a shape, as described above, for example, when moving the rotating operation part  122  (see  FIG. 3( a )  and  FIG. 3( b ) ) from the rotatable position to the rotation prohibited position, the inner peripheral recesses-projections  202  (see  FIG. 3( a )  and  FIG. 3( b ) ) of the rotating tubular part  124  (see  FIG. 3( a )  and  FIG. 3( b ) ) and the outer peripheral recesses-projections  204  of the fixed tubular part  106  can be appropriately and naturally engaged with each other. Accordingly, for example, it is possible to appropriately prevent giving the user an impression of being in the locked state while it is actually in the unlocked state. 
     Here, as can be understood from the above description, in the fixed tubular part  106  of the present example, the depth of the recess  224  may be constant except in the vicinity of one end part. Therefore, regarding the shape of the recess  224 , for example, the depth may gradually change in the vicinity of one end part, and the depth may be constant in the other portion. Further, as described above, in the fixed tubular part  106 , a chamfering process may be performed on the portion at which the outer peripheral surface and the end surface are connected. Then, in this case, the chamfering process may cause a change in the shape of a part of the recess  224 . However, in this case, as can be understood from  FIG. 11( b ) , for example, the depth and the width of the recess  224  may gradually increase toward the end part. Further, in this case, for example, as shown in  FIG. 11( b ) , the depth of at least a part of the recess  224  in the vicinity of the end part may be made deeper than the portion removed by the chamfering process. Further, in this case, the shape of the recess  224  may also be recessed from the chamfered surface, i.e., the surface that is chamfered, for example. “Being recessed from the chamfered surface” may mean, for example, that a dent forming a part of the recess  224  is formed on the chamfered surface. By forming the recess  224  having such a shape, for example, the widths of the projection  222  and the recess  224  can be appropriately changed in the vicinity of the end part of the fixed tubular part  106 . 
     Next, modified examples associated with the configuration described above will be described.  FIG. 12( a )  and  FIG. 12( b )  are views showing modified examples of the configuration of the impact position adjusting part  22  (see  FIG. 3( a )  and  FIG. 3( b ) ).  FIG. 12( a )  shows a modified example of the configuration of the rotating tubular part  124  in the impact position adjusting part  22 .  FIG. 12( b )  shows a modified example of the configuration of the fixed tubular part  106  in the impact position adjusting part  22 . Except for points described below, in  FIG. 12( a )  and  FIG. 12( b ) , the configurations labeled with the same reference numerals as those in  FIG. 1  to  FIG. 11( c )  may have the same or similar characteristics as the configurations in  FIG. 1  to  FIG. 11( c ) . 
     In the above description, among the rotating tubular part  124  and the fixed tubular part  106  used to realize the locking function in the impact position adjusting part  22 , the configuration in which the widths of the projection  222  and the recess  224  on the side of the fixed tubular part  106  are gradually changed toward the end part has mainly been described. However, in the modified example of the configuration of the impact position adjusting part  22 , as shown in  FIG. 12( a ) , for example, the widths of the projection  212  and the recess  214  on the side of the rotating tubular part  124  may also be gradually changed toward the end part. In this case, for example, the inner peripheral recesses-projections  202  of the rotating tubular part  124  may have a projection  212  of which the width gradually decreases toward the end part in the vicinity of the end part on the side close to the fixed tubular part  106 . Further, for example, the width of the recess  214  of the inner peripheral recesses-projections  202  may gradually increase toward the end part. Similarly, in this configuration, for example, when moving the rotating operation part  122  (see  FIG. 3( a )  and  FIG. 3( b ) ) from the rotatable position to the rotation prohibited position, the inner peripheral recesses-projections of the rotating tubular part  124  and the outer peripheral recesses-projections  204  of the fixed tubular part  106  can be appropriately and naturally engaged with each other. Further, for example, the shapes of the projection  212  and the recess  214  in the rotating tubular part  124  may also be shapes the same as or similar to the modified example of the configuration of the fixed tubular part  106  to be described below. Further, in a further modified example of the configuration of the impact position adjusting part  22 , for example, the widths of the projection  222  and the recess  224  in the fixed tubular part  106  may be made constant, and only the widths of the projection  212  and the recess  214  of the rotating part  102  may be gradually changed. 
     Further, in a modified example of the configuration of the impact position adjusting part  22 , for example, the widths of the projection  222  and the recess  224  of the outer peripheral recesses-projections  204  of the fixed tubular part  106  may be changed with a shape different from the specific configuration described above. Specifically, in the above description, the shapes of the projection  222  and the recess  224  have been mainly described as ones in which the pattern on one side and the pattern on the other side in the circumferential direction of the outer peripheral surface are the same (symmetrical). However, for example, as shown in  FIG. 12( b ) , in the shape of the projection  222  or the recess  224 , the pattern on one side and the pattern on the other side in the circumferential direction of the outer peripheral surface may be different. Similarly, in this case, by using the projection  222  of which the width gradually decreases toward the end part, for example, the inner peripheral recesses-projections  202  of the rotating tubular part  124  and the outer peripheral recesses-projections  204  of the fixed tubular part  106  can be appropriately and naturally engaged with each other. 
     Further, in the above description, the configuration in which the width is changed with respect to only a part of the projection  222  and the recess  224  has been mainly described. However, in a further modified example of the configuration of the impact position adjusting part  22 , for example, the width of the projection  222  or the recess  224  of the outer peripheral recesses-projections  204  of the fixed tubular part  106  may be gradually changed over the entire projection  222  or recess  224 . Similarly, in this case, by gradually decreasing the width of the projection  222  toward the end part at least in the vicinity of the end part, for example, the inner peripheral recesses-projections  202  of the rotating tubular part  124  and the outer peripheral recesses-projections  204  of the fixed tubular part  106  can be appropriately and naturally engaged with each other. 
     Further, in the above description, the configuration in which the inner peripheral recesses-projections  202  are formed on the inner peripheral surface of the rotating tubular part  124  and the outer peripheral recesses-projections  204  are formed on the outer peripheral surface of the fixed tubular part  106  has been mainly described. However, in a modified example of the configuration of the impact position adjusting part  22 , for example, the outer peripheral surface of the rotating tubular part  124  is formed with outer peripheral recesses-projections the same as or similar to the outer peripheral recesses-projections  204  described above, the inner peripheral surface of the fixed tubular part  106  is formed with inner peripheral recesses-projections the same as or similar to the inner peripheral recesses-projections  202  described above, and the locking function may be realized by engaging the outer peripheral recesses-projections with the inner peripheral recesses-projections. Further, in this case, for example, the rotating tubular part  124  may be an example of the first tubular part and the fixed tubular part  106  may be an example of the second tubular part. Similarly, in the case of this configuration, for example, the outer peripheral recesses-projections of the rotating tubular part  124  and the inner peripheral recesses-projections of the fixed tubular part  106  can be appropriately and naturally engaged with each other. 
     Further, in the above description, among the configurations which are examples of the operation adjusting part of the optical sight  10 , the configuration of the impact position adjusting part  22  has been mainly described. In this regard, in the case of adjustment associated with the perception of the target object with the optical sight  10  such as the adjustment with the focus adjusting part  24  (see  FIG. 1 ), for example, if an unintended deviation occurs after the adjustment, the user may easily notice the deviation by seeing a change in the perception of the target object. In contrast, in the case of the adjustment with the impact position adjusting part  22 , even if an unintended deviation occurs after the adjustment, it may be difficult for the user to notice. Therefore, with the impact position adjusting part  22 , if the user is given an impression that locking has been completed while it is actually in the unlocked state, the user&#39;s hand or an object may unintentionally touch the impact position adjusting part  22  and cause a deviation to the adjustment result, and the deviation tends to remain unnoticed by the user. Therefore, it is particularly important to prevent such misrecognition in the impact position adjusting part  22 . However, it is possible to also prevent such misrecognition of the lock mechanism in parts other than the impact position adjusting part  22 . Therefore, in the optical sight  10 , the configuration of an operation adjusting part other than the impact position adjusting part  22  may also use a lock mechanism the same as or similar to the lock mechanism of the impact position adjusting part  22  described above. In this case, for example, the configurations of the focus adjusting part  24  and the illumination adjusting part  26  may suitably be configurations having the same or similar lock mechanism as described above. With this configuration, for example, it is possible to appropriately realize an operation adjusting part that can be locked more appropriately. 
     Further, when considering more generally, the same or similar lock mechanism as the impact position adjusting part  22  of the present example may be suitably used in an operation adjusting part of an optical device other than the optical sight  10 . Specifically, in optical devices such as binoculars and telescopes, operation adjusting parts associated with this function may use a configuration having a lock mechanism the same as or similar to the lock mechanism of the impact position adjusting part  22  described above. With such a configuration, for example, it is possible to appropriately realize a configuration capable of performing adjustment more appropriately to a configuration for adjusting the functions of the optical device.