Locking device, fitting, and method for manufacturing unlocking key

Abstract

Provided is a locking device capable of locking / unlocking by inserting an unlocking key into a keyhole regardless of the direction of the unlocking key with respect to the keyhole. The present invention provides a locking device comprising a cylinder lock that has an inner cylinder having a circular keyhole and an outer cylinder rotatably fitting to the inner cylinder, and an unlocking key having a columnar key body which can be inserted into the keyhole of the cylinder lock, wherein: the cylinder lock has, at a rear-end section of the inner cylinder, a protruding section protruding in a fixed form in the keyhole; the unlocking key has, at a distal-end section of the key body, a depressed section that is depressed from a distal-end surface of the key body to an outer peripheral surface thereof and that is engageable with the protruding section; and the locking device is configured such that the unlocking key is positioned in the axial direction as a result of the distal-end surface of the key body inserted into the keyhole coming into contact with the protruding section, the protruding section and the depressed section engage with each other as a result of the unlocking key in a state of being positioned in the axial direction being rotationally operated around the central axis of the cylinder lock, and thus, the driving force during the rotational operation of the unlocking key can be transmitted to the inner cylinder.

Description

Manufacturing method for locking devices, fixtures, and unlocking keys

[0001] The present disclosure relates to a method for manufacturing a locking device, a fixture, and an unlocking key.

[0002] Conventionally, a locking device including a cylinder lock installed on a door of a residence or the like and an unlocking key for locking and unlocking the cylinder lock has been known (see, for example, Patent Document 1). The cylinder lock includes an inner cylinder, an outer cylinder into which the inner cylinder is rotatably fitted, and multiple tumbler pins that restrict the rotation of the inner cylinder. The unlocking key has projections and recesses that align the tumbler pins to a predetermined radial position. When the tumbler pins engage with the projections and recesses of the unlocking key inserted into the keyhole and the sheer line of the tumbler pins is aligned between the inner cylinder and the outer cylinder, the inner cylinder can rotate relative to the outer cylinder. To position the projections and recesses of the unlocking key and the tumbler pins along the axial direction of the cylinder lock, the unlocking key has a shoulder that abuts against the surface of the keyhole. When the unlocking key is inserted into the keyhole until the shoulder abuts against the surface of the keyhole, the projections and recesses of the unlocking key and the tumbler pins are aligned.

[0003] Japanese Patent Application Laid-Open No. 2007-191861

[0004] Generally, an unlocking key is formed in a plate shape with projections and depressions that engage with the tumbler pins, and the keyhole provided in the inner cylinder of the cylinder lock has a groove shape that is elongated in the radial direction of the inner cylinder to correspond to the shape of the unlocking key. This restricts the orientation of the unlocking key (the angle around the central axis of the cylinder lock) when inserted into the keyhole. In other words, if the keyhole is elongated vertically, the user must hold the plate-shaped unlocking key so that it is oriented vertically before inserting it into the keyhole. If the keyhole is elongated horizontally, the user must hold the plate-shaped unlocking key so that it is oriented horizontally before inserting it into the keyhole.

[0005] However, since users have different preferences regarding the orientation of the unlocking key when inserted into the keyhole, conventional locking devices are not necessarily user-friendly.

[0006] An object of the present disclosure is to provide a locking device that can lock and unlock a door by inserting an unlocking key into a keyhole, regardless of the orientation of the unlocking key relative to the keyhole.

[0007] The present disclosure relates to a locking device comprising: a cylinder lock having an inner cylinder with a circular keyhole and an outer cylinder rotatably fitted to the inner cylinder; and an unlocking key having a cylindrical key body that can be inserted into the keyhole of the cylinder lock, wherein the cylinder lock has a convex portion at the rear end of the inner cylinder that protrudes fixedly into the keyhole, and the unlocking key has a concave portion at the tip of the key body that is recessed from the tip surface of the key body to the outer peripheral surface and can engage with the convex portion, wherein the unlocking key is positioned axially when the tip surface of the key body inserted into the keyhole abuts against the convex portion, and the unlocking key in an axially positioned state is rotated around the central axis of the cylinder lock, whereby the concave portion and the convex portion engage with each other, and a driving force when the unlocking key is rotated can be transmitted to the inner cylinder.

[0008] 4 is a perspective view showing a locking device according to the present embodiment. FIG. 1 is an exploded perspective view of a cylinder lock. FIG. 2 is an exploded perspective view of the cylinder lock viewed from a direction different from that of FIG. 1. FIG. 3 is a front view of the cylinder lock viewed from the exterior side of the room. FIG. 4 is a rear view of the cylinder lock viewed from the interior side of the room. FIG. 5 is a side view showing a drive pin provided in the cylinder lock. FIG. 6 is a cross-sectional view of the cylinder lock taken along line A-A in FIG. 4. FIG. 7 is a front view of a cover member provided in the cylinder lock. FIG. 7 is a cross-sectional view of the cylinder lock showing a state in which the tip surface of the unlocking key inserted into the cylinder lock and the drive pin are in contact. FIG. 8 is a cross-sectional view of the cylinder lock showing a state in which the engagement groove of the unlocking key inserted into the cylinder lock and the drive pin are engaged. FIG. 9 is a perspective view showing a state in which the engagement groove of the unlocking key and the drive pin are engaged. FIG. 10 is a view showing another example of the arrangement of the engagement grooves provided in the unlocking key. FIG. 11 is a view explaining how engagement grooves are formed in the key body of the unlocking key. FIG. 12 is a plan view showing the engagement groove of the unlocking key according to another embodiment. FIG. 13 is a side view showing the engagement groove of the unlocking key according to another embodiment. FIG. 14 is a front view of a door equipped with a cylinder lock of the locking device according to the present embodiment.

[0009] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. The locking device according to this embodiment includes a cylinder lock 1 and an unlocking key 100 capable of locking and unlocking the cylinder lock 1. As shown in Figures 2 and 3 , the cylinder lock 1 includes an inner cylinder 2, an outer cylinder 3, a driver pin 41, a tumbler pin 42, a biasing member 43 formed of a spring that biases the driver pin 41 toward the tumbler pin 42, a click pin 5, and a pair of cover members 6.

[0010] Here, the directions in each figure will be defined. The direction indicated by the double-headed arrow in the figure indicates the direction along the central axis J of the cylinder lock 1. This direction coincides with the axial direction of the inner cylinder 2 and the outer cylinder 3. X1 indicates the front side of the cylinder lock 1, and X2 indicates the rear side of the cylinder lock 1. For example, if the cylinder lock 1 is attached to a front door, the front side X1 is the outside of the room, and the rear side X2 is the inside of the room.

[0011] 2 and 3, the inner cylinder 2 is a substantially cylindrical member that rotatably fits into the outer cylinder 3. The material of the inner cylinder 2 is not particularly limited, but it is made of a metal such as brass, for example. The inner cylinder 2 fits inside the outer cylinder 3. A keyhole 21, into which the unlocking key 100 can be inserted, is formed in the center of the inner cylinder 2 along the axial direction of the inner cylinder 2. The keyhole 21 has a circular opening facing the forward side X1.

[0012] As shown in FIGS. 2 and 3 , a plurality of cylindrical pin holes 22 communicating with the keyhole 21 are formed on the outer peripheral surface 20a of the inner cylinder 2. The pin holes 22 are holes into which at least a portion of the driver pin 41 and the tumbler pin 42 can be inserted and removed. In this embodiment, a single pin hole row is formed by arranging a plurality of pin holes 22 along the axial direction of the inner cylinder 2. The pin hole rows are formed in multiple rows in the circumferential direction of the inner cylinder 2. The inner cylinder 2 in this embodiment has four pin hole rows. The four pin hole rows are divided into two sets of pin hole rows, each set consisting of two circumferentially adjacent pin hole rows. The two sets of pin hole rows are separated by an angle of 180 degrees in the circumferential direction of the inner cylinder 2. The two sets of pin hole rows are arranged symmetrically with respect to the central axis J of the cylinder lock 1 and are radially opposed across the central axis J of the cylinder lock 1.

[0013] As shown in Figures 2, 3, and 7, the outer peripheral surface 20a at the end of the rear side X2 of the inner cylinder 2 has a plurality of fitting holes 23 formed at predetermined intervals in the circumferential direction, which communicate with the keyhole 21. In this embodiment, four fitting holes 23 are formed in the outer peripheral surface 20a of the inner cylinder 2. The four fitting holes 23 are divided into two sets of fitting holes 23, with two circumferentially adjacent fitting holes 23 forming one set. The two sets of fitting holes 23 are separated by an angle of 180 degrees in the circumferential direction of the inner cylinder 2. The two sets of fitting holes 23 are positioned symmetrically with respect to the central axis J of the cylinder lock 1 and are radially opposed across the central axis J of the cylinder lock 1. The inner peripheral surface of the fitting holes 23 on the keyhole 21 side is formed with a smaller diameter. As a result, an annular step 23a is formed on the inner peripheral surface of the fitting holes 23, as shown in Figure 7.

[0014] A drive pin 24 is inserted into each of the four fitting holes 23. As shown in FIG. 6 , the drive pin 24 has a large diameter portion 241, a small diameter portion 242, and a drive end portion 243, which are coaxially arranged in this order from the radial outside of the inner cylinder 2 along the axial direction of the drive pin 24. The large diameter portion 241 and the small diameter portion 242 are formed in a cylindrical shape. The drive end portion 243 is formed in a cylindrical shape with an outer diameter smaller than that of the small diameter portion 242. In the drive pin 24, the small diameter portion 242 is adjacent to the drive end portion 243 and has a diameter larger than that of the drive end portion 243.

[0015] The inside of the driving end 243 has a circular groove 244 that opens toward the keyhole 21. The depth of the groove 244 is equal to or greater than the protrusion height of the driving end 243 from the small diameter portion 242. The depth of the groove 244 is also equal to or greater than the protrusion height of the driving end 243 from the inner circumferential surface 20b of the inner cylinder 2 toward the keyhole 21. That is, the position of the bottom 244a of the groove 244 along the axial direction of the drive pin 24 is either aligned with the base 243a of the driving end 243, which is the boundary between the small diameter portion 242 and the driving end 243, or is positioned closer to the small diameter portion 242 than the base 243a. A conically protruding protrusion 245 is formed on the upper surface of the large diameter portion 241 (the surface opposite the small diameter portion 242). The apex 245a of the protrusion 245 is aligned with the central axis of the drive pin 24.

[0016] The drive pin 24 is inserted into the fitting hole 23 from the radially outer side of the inner tube 2. The large-diameter portion 241 of the drive pin 24 abuts against the annular step portion 23a of the fitting hole 23, preventing further insertion toward the keyhole 21. The large-diameter portion 241 and small-diameter portion 242 of the drive pin 24 are completely housed within the fitting hole 23. The large-diameter portion 241 does not protrude radially outward beyond the outer peripheral surface 20a of the inner tube 2. The small-diameter portion 242 does not protrude radially inward beyond the inner peripheral surface 20b of the inner tube 2. The raised portion 245 of the drive pin 24 faces the outer peripheral surface 20a of the inner tube 2 and makes point contact with the inner peripheral surface 30b of the outer tube 3. This prevents the drive pin 24 from moving radially outward by the outer tube 3. The drive pin 24 does not rattle in the radial direction of the cylinder lock 1 and does not interfere with the rotation of the inner cylinder 2 relative to the outer cylinder 3.

[0017] In this state, the drive ends 243 are positioned to protrude from the fitting holes 23 into the keyway 21, as shown in Figures 4, 5, and 7. Two adjacent drive ends 243 in the circumferential direction of the inner cylinder 2 are spaced apart by an angle of 180 degrees along the circumferential direction of the inner cylinder 2 and are positioned opposite each other in the radial direction of the inner cylinder 2, with the central axis J of the cylinder lock 1 in between. As a result, the drive ends 243 of the four drive pins 24 form four protrusions that protrude fixedly into the keyway 21. As will be described later, these engage with engagement grooves 111 provided at the tip of the key body 110 of the unlocking key 100, and transmit the drive force to the inner cylinder 2 when the unlocking key 100 is turned.

[0018] 3 and 5, a recess 25 into which a click pin 5, which will be described later, fits is formed on the outer peripheral surface 20a at the end on the rear side X2 of the inner cylinder 2. The recess 25 extends along the axial direction of the inner cylinder 2. The width of the recess 25 along the circumferential direction of the outer peripheral surface 20a of the inner cylinder 2 is smaller than the outer diameter of the cylindrical click pin 5, as shown in FIG.

[0019] As shown in FIGS. 2 and 3 , the outer cylinder 3 is a substantially cylindrical member into which the inner cylinder 2 can be fitted. The material of the outer cylinder 3 is not particularly limited, but, like the inner cylinder 2, it may be made of a metal such as brass. The outer cylinder 3 is fixed to a door (not shown) to which the cylinder lock 1 is attached so as not to rotate. The outer cylinder 3 is fitted to the inner cylinder 2 by abutting the inner circumferential surface 30b, which is the sliding surface with the inner cylinder 2, against the outer circumferential surface 20a of the inner cylinder 2. The axial length of the outer cylinder 3 is slightly shorter than the axial length of the inner cylinder 2. As a result, as shown in FIG. 7 , the inner cylinder 2, fitted to the outer cylinder 3 with the front side X1 aligned, protrudes toward the rear side X2 beyond the outer cylinder 3. The portion of the inner cylinder 2 protruding toward the rear side X2 beyond the outer cylinder 3 is used for connection to functional components (not shown) of the cylinder lock 1.

[0020] The outer cylinder 3 has a cylindrical hole 31 formed along the axial direction of the outer cylinder 3, into which the inner cylinder 2 can fit. A plurality of cylindrical pin holes 32 communicating with the hole 31 are formed on the outer peripheral surface 30a of the outer cylinder 3. The pin holes 32 are holes into which at least a portion of the driver pin 41 and the tumbler pin 42 can be inserted and removed. The pin holes 32 of the outer cylinder 3 are arranged to be able to communicate with the pin holes 22 of the inner cylinder 2. In this embodiment, a single pin hole row is formed by arranging the pin holes 32 along the axial direction of the outer cylinder 3. The outer cylinder 3 of this embodiment has four pin hole rows arranged to correspond to the positions of the four pin hole rows of the inner cylinder 2. Therefore, the four pin hole rows of the outer cylinder 3 are divided into two sets of pin hole rows, each set consisting of two circumferentially adjacent pin hole rows. The two sets of pin hole rows are spaced 180 degrees apart circumferentially of the outer cylinder 3. The two sets of pin hole rows are arranged symmetrically with respect to the central axis J of the cylinder lock 1, and are opposed radially across the central axis J of the cylinder lock 1. The pin holes 22 of the inner cylinder 2 and the pin holes 32 of the outer cylinder 3 communicate with each other so that at least a portion of the driver pin 41 and the tumbler pin 42 can be inserted and removed when the inner cylinder 2 is rotated relative to the outer cylinder 3 and placed in a predetermined position.

[0021] As shown in Figures 2 to 5, a lid material mounting groove 33 is provided in the outer peripheral surface 30a of the outer cylinder 3 along the axial direction. The lid material mounting groove 33 has a substantially rectangular shape in cross section and opens to the outer peripheral surface 30a of the outer cylinder 3. The lid material mounting groove 33 is formed from the end face of the outer cylinder 3 on the front side X1 to the end face of the outer cylinder 3 on the rear side X2. In this embodiment, two lid material mounting grooves 33 are provided in the outer peripheral surface 30a of the outer cylinder 3. As shown in Figures 4 and 5, the two lid material mounting grooves 33 are arranged 180 degrees apart in the circumferential direction of the outer peripheral surface 30a of the outer cylinder 3. The two lid material mounting grooves 33 are configured to be engageable with a bent portion 62 of the lid material 6, which will be described later.

[0022] 3 and 5, a notch 34 is formed along the axial direction at the end of the rear side X2 of the outer tube 3. The notch 34 is arranged to be able to communicate with the recess 25 of the inner tube 2. The notch 34 is formed by cutting out the outer peripheral surface 30a from the end face of the rear side X2 of the outer tube 3 toward the front side X1 so as to have a substantially rectangular parallelepiped shape in a plan view. The hole 31 communicates with the radial outside of the outer tube 3 via the notch 34. The notch width and length of the notch 34 are substantially equal to the outer diameter and axial length of the cylindrical click pin 5.

[0023] The driver pin 41 and the tumbler pin 42 are each a substantially cylindrical member. The driver pin 41 and the tumbler pin 42 are housed in the pin hole 22 of the inner cylinder 2 and the pin hole 32 of the outer cylinder 3, respectively, so as to be slidable in the radial direction of the inner cylinder 2 and the outer cylinder 3. The tumbler pin 42 is a pin that is arranged on the keyhole 21 side of the pin holes 22, 32. The tip of the tumbler pin 42 is arranged to protrude into the keyhole 21 so as to be able to come into contact with the key body 110 of the unlocking key 100 inserted into the keyhole 21. The tip of the tumbler pin 42 has a rounded shape. One end of the driver pin 41 abuts the tumbler pin 42, and the other end abuts the biasing member 43. 2 and 3 show only one set of driver pin 41, tumbler pin 42, and urging member 43, but the sets of driver pins 41, tumbler pins 42, and urging members 43 are provided in accordance with the number of pin holes 22, 32 in the inner cylinder 2 and the outer cylinder 3. In Figures 4, 5, 7, 9, and 10, the tumbler pins 42 protruding into the keyhole 21 are not shown.

[0024] The click pin 5 is a member that suppresses rotation of the inner tube 2 relative to the outer tube 3 when the rotational state of the inner tube 2 relative to the outer tube 3 is such that the unlocking key 100 can be inserted and removed from the keyhole 21. The click pin 5 is cylindrical. The axial direction of the click pin 5 is aligned with the axial directions of the inner tube 2 and the outer tube 3. A constricted portion 5a is formed around the entire circumference at the center of the axial direction of the click pin 5. As shown in FIG. 5 , when the inner tube 2 and the outer tube 3 are fitted together, the click pin 5 is positioned to fit into the recess 25 of the inner tube 2 and is completely housed within the cutout portion 34 of the outer tube 3. The click pin 5 within the cutout portion 34 does not protrude radially outward beyond the outer circumferential surface 30a of the outer tube 3.

[0025] The click pin 5 housed in the cutout portion 34 is urged toward the inner cylinder 2 by an arc-shaped torsion spring 51 serving as a urging member. The torsion spring 51 is attached to a spring mounting groove 35 formed along the circumferential direction on the outer peripheral surface 30a at the end of the rear side X2 of the outer cylinder 3. Two ends 51a of the torsion spring 51 are engaged with spring locking grooves 36 formed on the outer peripheral surface 30a of the outer cylinder 3. The torsion spring 51 attached to the spring mounting groove 35 engages with the narrowed portion 5a of the click pin 5 and applies a urging force from the radially outside of the outer cylinder 3.

[0026] 5, the click pin 5 in the cutout portion 34 of the outer cylinder 3 is fitted into the recess 25 of the inner cylinder 2. At this time, rotation of the inner cylinder 2 relative to the outer cylinder 3 is restricted, and the clicking sensation when the click pin 5 fits into the recess 25 is transmitted to the fingers of the user who is rotating the unlocking key 100. This allows the user to recognize the position at which the unlocking key 100 can be inserted or removed, and allows the user to easily maintain the rotated state of the inner cylinder 2 relative to the outer cylinder 3 in the insertable / removable position. The torsion spring 51 that biases the click pin 5 engages with the constricted portion 5a of the click pin 5 and is attached to the spring mounting groove 35 of the outer cylinder 3. Therefore, the outer diameter of the outer cylinder 3 does not increase, and the diameter of the cylinder lock 1 can be reduced.

[0027] The lid member 6 is attached along the outer peripheral surface 30a of the outer tube 3, thereby covering the multiple pin holes 32 opening in the outer peripheral surface 30a. The lid member 6 is attached to the outer tube 3 while resisting the biasing force of the biasing member 43, which applies a biasing force to the driver pin 41. As a result, the driver pin 41 is accommodated in the pin hole 32 and is subjected to a biasing force toward the radially inward direction of the outer tube 3. By having the lid member 6 cover the multiple pin holes 32 of the outer tube 3, the arrangement space for the grooves for fixing the lid member can be reduced compared to a lid member that covers each row of the driver pin holes. This allows the diameter of the outer tube 3 to be reduced. As shown in FIGS. 1 and 7 , the rear side X2 end of the lid member 6 does not cover the spring mounting groove 35.

[0028] In this embodiment, two lid members 6 are provided on the outer cylinder 3. The two lid members 6 are combined to form a substantially cylindrical shape on the outer peripheral surface 30a of the outer cylinder 3. By providing multiple lid members 6, the assembly workability of the cylinder lock 1 can be improved compared to when a single cylindrical lid member is used. Spring steel is preferably used as the material for the lid members 6. This makes it possible to closely contact the lid members 6 and the outer cylinder 3 without any gaps. In particular, it is more preferable to use stainless steel spring steel. Specifically, SUS304CSP can be used.

[0029] As shown in Fig. 8, the cover material 6 has a curved portion 61 having a shape obtained by curving a flat plate along the outer peripheral surface 30a of the outer cylinder 3, and bent portions 62 formed on both ends of the curved portion 61. The curved portion 61 has a substantially semicircular cross-sectional shape. The bent portions 62 are arranged on both ends of the curved portion 61 in the direction of curvature, and are each bent toward the inside of the curved portion 61. The two cover materials 6, 6 have the same shape and are arranged in positions symmetrical about the central axis J of the cylinder lock 1.

[0030] The two lid members 6 are attached to the outer peripheral surface 30a of the outer cylinder 3 by engaging their respective bent portions 62 with two lid member attachment grooves 33, 33 formed on the outer peripheral surface 30a of the outer cylinder 3. Before the lid members 6 are attached to the outer cylinder 3, the curved portions 61 of the lid members 6 are curved inward with a curvature slightly larger than the curvature of the outer peripheral surface 30a of the outer cylinder 3. Therefore, when the lid members 6 are attached to the outer cylinder 3, the spring force exerted by the curved portions 61 causes the bent portions 62 to be firmly engaged with the lid member attachment grooves 33 and the curved portions 61 to be in close contact with the outer cylinder 3.

[0031] Next, a description will be given of the axial retaining structure of the inner cylinder 2 and the outer cylinder 3 in the cylinder lock 1 of this embodiment.

[0032] 2, 3, and 7, a fixing pin insertion groove 26 extending circumferentially is formed in the outer peripheral surface 20a of the inner cylinder 2. As shown in FIG. 7, the fixing pin insertion groove 26 is a groove with a rectangular cross section that is recessed in the axial direction from the outer peripheral surface 20a of the inner cylinder 2 toward the keyhole 21 and has the same width. In this embodiment, the fixing pin insertion groove 26 is located at the end of the front side X1 of the inner cylinder 2 and is formed in an annular shape by cutting the outer peripheral surface 20a around the entire circumference. The multiple pin holes 22 in the inner cylinder 2 are located on the rear side X2 of the fixing pin insertion groove 26.

[0033] 2, 3, and 7, a cylindrical fixing pin insertion hole 37 is formed in the outer peripheral surface 30a at the end of the front side X1 of the outer cylinder 3 at a position corresponding to the fixing pin insertion groove 26 of the inner cylinder 2. The fixing pin insertion hole 37 communicates with the hole portion 31. As shown in FIGS. 1 and 7, the end of the front side X1 of the lid member 6 does not cover the fixing pin insertion hole 37.

[0034] 7 , the inner diameter of the fixing pin insertion hole 37 is larger than the groove width of the fixing pin insertion groove 26 along the axial direction of the inner cylinder 2. Therefore, when the inner cylinder 2 and the outer cylinder 3 are fitted together, the fixing pin insertion groove 26 and the steps 26a located on the front side X1 and rear side X2 of the fixing pin insertion groove 26 face into the fixing pin insertion hole 37. The steps 26a are formed by part of the outer peripheral surface 20a of the inner cylinder 2.

[0035] A plurality of fixing pin insertion holes 37 are formed in the outer cylinder 3. In this embodiment, four fixing pin insertion holes 37 are formed in the outer cylinder 3. Two sets of fixing pin insertion holes 37, each consisting of two fixing pin insertion holes 37, are arranged along the circumferential direction of the outer cylinder 3, with the lid mounting groove 33 sandwiched between them. As shown in FIG. 4 , the angle θ at which the central axes 37a of the two fixing pin insertion holes 37 constituting one set intersect with the circumferential direction of the outer cylinder 3 is less than 180 degrees. The lower limit of this angle θ is set to an angle at which the two fixing pin insertion holes 37 do not interfere with each other and the two inner and outer cylinder fixing pins 7 (described later) inserted into each fixing pin insertion hole 37 do not interfere with each other. The specific angle θ is not particularly limited as long as it is other than 180 degrees, but it can be set to, for example, 30 degrees.

[0036] At least two of the multiple fixation pin insertion holes 37 can accommodate inner / outer cylinder fixation pins 7. In this embodiment, two of the four fixation pin insertion holes 37 that make up one set are each fitted with a metal inner / outer cylinder fixation pin 7. As shown in FIGS. 4 and 7 , the inner / outer cylinder fixation pin 7 has a cylindrical small-diameter portion 71, a large-diameter portion 72, and a positioning end portion 73, arranged in this order from the radial outside of the outer cylinder 3 along the axial direction of the inner / outer cylinder fixation pin 7. The outer diameter of the large-diameter portion 72 is equal to or smaller than the inner diameter of the fixation pin insertion hole 37 and is larger than the groove width of the fixation pin insertion groove 26 along the axial direction of the inner cylinder 2. The outer diameter of the positioning end portion 73 is smaller than the outer diameter of the large-diameter portion 72 and is equal to or smaller than the groove width of the fixation pin insertion groove 26 along the axial direction of the inner cylinder 2. The inner / outer cylinder fixing pin 7 in this embodiment is a fixing pin that restricts the axial movement of the inner cylinder 2 so that the inner cylinder 2 does not slip out of the outer cylinder 3 in the axial direction, and fixes it.

[0037] The axial length of the inner / outer cylinder fixing pin 7 is greater than the axial length of the fixing pin insertion hole 37. Specifically, the combined axial length of the small diameter portion 71 and the large diameter portion 72 of the inner / outer cylinder fixing pin 7 is shorter than the axial length of the fixing pin insertion hole 37. The axial length of the positioning end portion 73 of the inner / outer cylinder fixing pin 7 is equal to or less than the depth of the fixing pin insertion groove 26 of the inner cylinder 2.

[0038] When the inner / outer cylinder fixing pin 7 is inserted into the fixing pin insertion hole 37 from the radial outside of the outer cylinder 3, with the positioning end 73 leading, the large-diameter portion 72 of the inner / outer cylinder fixing pin 7 abuts against the step 26a facing the fixing pin insertion hole 37, preventing further insertion. In this state, the positioning end 73 of the inner / outer cylinder fixing pin 7 penetrates the fixing pin insertion hole 37 of the outer cylinder 3 and is inserted into the fixing pin insertion groove 26 of the inner cylinder 2, as shown in Figures 4 and 7. As a result, the inner cylinder 2 is positioned relative to the outer cylinder 3 so that it cannot slip out in the axial direction, and is fitted into the hole 31 of the outer cylinder 3. The positioning end 73 of the inner / outer cylinder fixing pin 7 can move circumferentially within the fixing pin insertion groove 26 of the inner cylinder 2. Therefore, when the cylinder lock 1 is unlocked by inserting the unlocking key 100 into the keyway 21, the inner cylinder 2 can freely rotate relative to the outer cylinder 3.

[0039] The inner cylinder 2 is positioned so that it cannot slip out in the axial direction by the inner / outer cylinder fixing pin 7, which is inserted from the radial outside of the outer cylinder 3, so there is no need to sandwich the outer cylinder 3 from both sides in the axial direction by the inner cylinder 2. Since the axial lengths of the inner cylinder 2 and outer cylinder 3 can be made as short as possible, the cylinder lock 1 can be made smaller.

[0040] When the inner cylinder 2 and outer cylinder 3 are fitted together in this way, there are three tolerance relationships: the groove width of the fixing pin insertion groove 26 formed in the inner cylinder 2, the inner diameter of the hole 31 in the outer cylinder 3, and the outer diameter of the inner / outer cylinder fixing pin 7. Of these, except for the inner diameter of the hole 31 in the outer cylinder 3, the outer circumference is machined using a machine tool that cuts the fixing pin insertion groove 26 and the inner / outer cylinder fixing pin 7, so high-precision machining can be achieved. Therefore, the axial misalignment between the inner cylinder 2 and outer cylinder 3 can be minimized. Because the gap between the inner cylinder 2 and outer cylinder 3 can be reduced, the diameter of the cylinder lock 1 can be made smaller.

[0041] As shown in FIGS. 2 to 4 and 7 , the two inner / outer cylinder fixing pins 7 inserted into the two fixing pin insertion holes 37 are held down by a holding member 8 from the radial outside of the outer cylinder 3. This prevents the inner / outer cylinder fixing pins 7 from slipping out of the outer cylinder 3 due to their own weight. In this embodiment, the holding member 8 is an arc-shaped spring member formed by bending a rod-shaped body made of metal with spring elasticity along the circumferential direction of the outer cylinder 3. Locking portions 8a bent in the same direction are formed at both ends of the holding member 8. The holding member 8 is housed in an accommodation groove 38 formed along the circumferential direction on the outer peripheral surface 30a at the end of the front side X1 of the outer cylinder 3. The accommodation groove 38 is formed around the entire circumference of the outer cylinder 3 and crosses the two fixing pin insertion holes 37.

[0042] Two presser member locking grooves 331 are formed on the outer peripheral surface 30a of the outer tube 3 and are spaced apart in the circumferential direction. The two presser member locking grooves 331 are recessed into the outer peripheral surface 30a at the end of the front side X1 of the outer tube 3 so as to open radially outward of the outer tube 3 and toward the front side X1. The presser member locking grooves 331 are positioned offset with respect to the lid material mounting groove 33 toward the two fixing pin insertion holes 37 into which the two inner and outer tube fixing pins 7 are inserted. The two presser member locking grooves 331 are each circumferentially connected to the lid material mounting groove 33 on the outer peripheral surface 30a of the outer tube 3.

[0043] The length between the two locking portions 8a along the arc shape of the pressing member 8 is slightly shorter than the distance between the two pressing member locking grooves 331 along the circumferential direction of the outer tube 3. Therefore, the pressing member 8 is elastically mounted in the accommodating groove 38 along the circumferential direction of the outer tube 3 by fitting the locking portions 8a into the pressing member locking grooves 331, respectively.

[0044] The retaining member 8 attached to the accommodating groove 38 is positioned within the accommodating groove 38 so as to cross the end faces of the small diameter portions 71 of the two inner and outer cylinder fixing pins 7. This allows the two inner and outer cylinder fixing pins 7 to be pressed from the radial outside of the outer cylinder 3 so as not to slip out of the fixing pin insertion holes 37. As shown in FIGS. 4 and 7 , the end faces of the small diameter portions 71 of the inner and outer cylinder fixing pins 7 inserted into the fixing pin insertion holes 37 are positioned at a position recessed radially inward from the outer peripheral surface 30a of the outer cylinder 3 by a distance at least equal to the outer diameter of the rod-shaped body forming the retaining member 8. The depth of the accommodating groove 38 is at least equal to or greater than the outer diameter of the rod-shaped body forming the retaining member 8. This means that even when the retaining member 8 presses the two inner and outer cylinder fixing pins 7 from the radial outside of the outer cylinder 3, the outer diameter of the outer cylinder 3 does not increase, and does not hinder the cylinder lock 1 from being made smaller in diameter.

[0045] The retaining member 8 merely holds the inner / outer cylinder fixing pin 7 to the extent that it does not slip out of the fixing pin insertion hole 37, and does not substantially apply a biasing force to the inner / outer cylinder fixing pin 7 toward the inner cylinder 2. Because the inner / outer cylinder fixing pin 7 does not press against the inner cylinder 2, it does not provide resistance when the inner cylinder 2 rotates relative to the outer cylinder 3. Therefore, the inner cylinder 2 can rotate smoothly relative to the outer cylinder 3.

[0046] Because the central axes 37a of the two fixing pin insertion holes 37 intersect at an angle θ of less than 180 degrees, the central axes 7a of the two inner and outer cylinder fixing pins 7 inserted into the two fixing pin insertion holes 37 also intersect at an angle θ of less than 180 degrees. This prevents rattling of the inner cylinder 2 relative to the outer cylinder 3 in the direction of rotation about the central axes 7a of the inner and outer cylinder fixing pins 7.

[0047] Axial positioning and retention of the inner and outer cylinders 2 and 3 can be achieved simply by inserting the inner and outer cylinder fixing pin 7 into the fixing pin insertion hole 37 from the radial outside of the outer cylinder 3 and pressing it down with the retaining member 8, making it easy to fit the inner and outer cylinders 2 and 3 together. Because the fixing pin insertion hole 37 is not covered by the lid member 6, the positioning of the inner and outer cylinders 2 and 3 can be easily released by simply removing the retaining member 8 from the outer cylinder 3 and pulling out the inner and outer cylinder fixing pin 7 from the fixing pin insertion hole 37. The inner and outer cylinder fixing pin 7 can be easily pulled out by grasping the small diameter portion 71 with a tool such as tweezers.

[0048] The cylinder lock 1 according to this embodiment is configured to insert the inner and outer cylinder fixing pins 7 into two of the four fixing pin insertion holes 37 that make up one set of four fixing pin insertion holes 37 formed in the outer cylinder 3, but the two inner and outer cylinder fixing pins 7 may be configured to be inserted into any two of the four fixing pin insertion holes 37, provided that they are not arranged at an angle of 180 degrees around the circumference of the outer cylinder 3. The fixing pin insertion holes 37 may be inserted into all four fixing pin insertion holes 37.

[0049] Next, the unlocking key 100 will be described.

[0050] The unlocking key 100 has a key body 110 made of a cylindrical rod-shaped body and a plate-shaped grip part 120 provided at the rear end (the end on the left side in FIG. 1 ) of the key body 110. The key body 110 extends straight in one direction from the grip part 120.

[0051] As shown in FIGS. 1 and 9 to 11 , four engagement grooves 111 are formed in the tip of the key body 110 farthest from the grip portion 120 (the right end in FIG. 1 ). The four engagement grooves 111 correspond to the arrangement of the four drive ends 243 protruding into the keyhole 21 of the inner cylinder 2. That is, the four engagement grooves 111 are divided into two sets of engagement grooves 111, each set consisting of two engagement grooves 111 adjacent to each other in the circumferential direction of the key body 110. The two sets of engagement grooves 111 are separated by an angle of 180 degrees in the circumferential direction of the key body 110. The two sets of engagement grooves 111 are arranged symmetrically with respect to the central axis of the key body 110.

[0052] The four engagement grooves 111 are of the same shape and are recessed from the tip surface 110a to the outer peripheral surface 110b of the key body 110, extending along the length of the key body 110. The engagement grooves 111 of the unlocking key 100 form recesses that can engage with the driving end 243. The length of the key body 110 from the grip portion 120 of the unlocking key 100 to the engagement grooves 111 is equal to or greater than the length from the front end surface 20c of the inner cylinder 2 to the driving end 243 that protrudes into the keyhole 21 of the inner cylinder 2.

[0053] The outer peripheral surface 110b of the key body 110 does not have a restricting portion formed of a groove or protrusion for restricting the position of the cylinder lock 1 around the central axis J when inserted into the keyhole 21. The outer peripheral surface 110b of the key body 110 has grooves (not shown) formed thereon that correspond to the arrangement of the multiple tumbler pins 42 provided in the cylinder lock 1, but these are not shown in the drawing. The key body 110 does not have a shoulder that abuts against the surface of the keyhole 21.

[0054] Next, the locking and unlocking operation of the cylinder lock 1, which is performed by inserting the unlocking key 100 into the keyhole 21, will be described.

[0055] As shown in FIG. 1 , the user first inserts the key body 110 of the unlocking key 100 into the keyway 21 of the inner cylinder 2 of the cylinder lock 1 from the front side X1. The orientation of the unlocking key 100 (the angle around the central axis J of the cylinder lock 1) is such that the grip 120 is vertical, but the orientation of the unlocking key 100 is not important. In other words, when inserting the key body 110 of the unlocking key 100 into the keyway 21, the key body 110 can be inserted at any angle within 360 degrees. When the key body 110 is inserted deep into the keyway 21, the tip surface 110 a of the key body 110 abuts against the drive end 243 protruding into the keyway 21, as shown in FIG. 9 . This stops the insertion movement of the unlocking key 100, and the unlocking key 100 is positioned axially. In this state, the positions of the four driving ends 243 and the positions of the four engaging grooves 111 of the key body 110 do not match, and so they do not engage with each other.

[0056] After the tip surface 110a of the key body 110 abuts against the driving end 243, when the user rotates the grip 120 clockwise or counterclockwise, the tip surface 110a of the key body 110 and the driving end 243 slide against each other, causing the key body 110 to rotate around the central axis J of the cylinder lock 1. During this process, when the positions of the four driving end portions 243 and the positions of the four engagement grooves 111 of the key body 110 match, the corresponding driving end portions 243 engage with the four engagement grooves 111 of the key body 110, as shown in Figures 10 and 11 . At this time, the unlocking key 100 advances a distance corresponding to the length of the engagement grooves 111 along the length of the key body 110. This allows the user to perceive that the engagement grooves 111 and the driving end portions 243 have engaged.

[0057] When the unlocking key 100 is an official key for the cylinder lock 1, with the four engagement grooves 111 and the four drive ends 243 engaged, the tips of the corresponding tumbler pins 42 fit into multiple grooves (not shown) formed on the outer circumferential surface 110b of the key body 110. As a result, the shear line between the driver pin 41 and the tumbler pins 42 coincides with the outer circumferential surface 20a of the inner cylinder 2. In this state, when the user further rotates the grip portion 120 of the unlocking key 100 clockwise or counterclockwise, the driving force generated by the rotation is transmitted to the inner cylinder 2 via the four engagement grooves 111 and the drive ends 243 of the four drive pins 24. This rotates the inner cylinder 2 relative to the outer cylinder 3, locking or unlocking the cylinder lock 1.

[0058] Since the outer peripheral surface 110b of the key body 110 of the unlocking key 100 does not have a restricting portion for restricting the position around the central axis J of the cylinder lock 1 when inserted into the keyhole 21, the user can insert the key body 110 into the keyhole 21 while holding the grip portion 120 of the unlocking key 100 at any angle of their choice, such as horizontally, not just vertically. Since the unlocking key 100 can be inserted into the keyhole 21 to lock or unlock the key regardless of the orientation of the unlocking key 100 relative to the keyhole 21, the locking device is easy to use for the user.

[0059] The key body 110 of the unlocking key 100 does not have a shoulder that abuts against the surface of the keyway 21 to position the not-shown groove and the tumbler pin 42 of the cylinder lock 1. The not-shown groove and the tumbler pin 42 of the cylinder lock 1 are positioned by the engagement between the engagement groove 111 of the key body 110 and the drive end 243 of the drive pin 24. Therefore, even if an unlocking key 100 whose key body 110 is longer than the keyway 21 is inserted into the keyway 21, the not-shown groove and the tumbler pin 42 of the cylinder lock 1 can be positioned. In other words, the same unlocking key 100 can be used to lock and unlock multiple cylinder locks with different keyway lengths.

[0060] The drive end 243 of the drive pin 24 is located adjacent to the small diameter portion 242, which is a portion with a larger diameter than the outer diameter of the drive end 243, and is formed cylindrically with a groove 244 on the inside, making it a weak portion with low rigidity on the drive pin 24. As a result, if a different unlocking key or the like is inserted into the keyhole 21 and an excessive load is applied to the drive end 243 in the rotational direction, the drive end 243 will break and it will no longer be possible to rotate the inner cylinder 2. Therefore, the cylinder lock 1 has high anti-theft properties.

[0061] The number of drive pins 24 provided on the inner cylinder 2 and the number of corresponding engagement grooves 111 on the unlocking key 100 are not limited to four each, and may be at least one each. At least two drive ends 243 are provided along the circumferential direction of the inner cylinder 2 and facing each other in the radial direction of the inner cylinder 2, and two engagement grooves 111 corresponding to the positions of the two drive ends 243 are provided at the tip of the key body 110, which is preferable because it allows the unlocking key 100 to be used in the same way even if the orientation (angle around the central axis J of the cylinder lock 1) is rotated 180 degrees.

[0062] However, the at least two drive ends 243 and the at least two engagement grooves 111 are not limited to being positioned 180 degrees apart. Figures 12A and 12B show other examples of engagement grooves 111 provided at the tip of the unlocking key 100. The tip of the unlocking key 100 shown in Figure 12A has four engagement grooves 111. Two of these engagement grooves 111, 111 are positioned 180 degrees apart around the circumferential direction of the key body 110 and face each other radially. The other two engagement grooves 111, 111 are positioned not facing each other. The tip of the unlocking key 100 shown in Figure 12B has four engagement grooves 111 that are not positioned facing each other. In this case, the drive pins 24 provided on the inner tube 2 are positioned to correspond to the positions of the engagement grooves 111 of the unlocking key 100.

[0063] Since the driving end 243 is located at the rear end of the cylinder lock 1, even if a picking tool is inserted into the keyhole 21 and the tumbler pin 42 is manipulated illicitly, the driving end 243 for rotating the inner cylinder 2 is located further back than the picking tool, making it difficult to rotate the inner cylinder 2. Therefore, the locking device of this embodiment has excellent anti-theft properties.

[0064] Next, a method for manufacturing the unlocking key 100 will be described with reference to FIG.

[0065] When forming multiple engagement grooves 111 arranged 180 degrees apart in the key body 110 of the unlocking key 100 as shown in FIG. 11 , the two engagement grooves 111, 111 arranged symmetrically with respect to the central axis Ja of the key body 110 are simultaneously machined using two processing tools T, T arranged symmetrically with respect to the central axis Ja of the key body 110. In FIG. 13 , the central axis Ja of the key body 110 is arranged at the center of the tip surface 110a of the key body 110 and extends perpendicular to the paper surface. The processing tool T is, for example, a cutting tool that performs groove machining by rotating. The two processing tools T, T are spaced 180 degrees apart around the central axis Ja of the key body 110. The two processing tools T, T are arranged in positions facing each other across the key body 110.

[0066] The two processing tools T, T simultaneously advance relative to the central axis Ja of the key body 110, simultaneously machining the two engagement grooves 111, 111. For example, if the engagement groove 111 is machined in the key body 110 using only one processing tool T, the key body 110 is pushed by the processing tool T and bends in a direction away from the processing tool T, making it difficult to perform high-precision groove machining. However, as in the present embodiment, by simultaneously machining the two engagement grooves 111, 111 using two processing tools T, T positioned opposite each other across the key body 110, bending of the key body 110 during machining is suppressed. Therefore, it is possible to machine the engagement groove 111 with high precision.

[0067] When manufacturing the unlocking key 100 shown in FIG. 12A , the two opposing engagement grooves 111, 111 can be machined simultaneously with two processing tools T, T, allowing for high-precision machining, similar to the above. When machining the other two non-opposing engagement grooves 111, 111 in FIG. 12A , it is also preferable to machine them simultaneously with two processing tools T, T. In this case, although the machining precision is lower than when machining the two opposing engagement grooves 111, 111, by simultaneously machining the two processing tools T, T so that their axial directions are directed toward the central axis Ja of the key body 110, deflection of the key body 110 during machining is suppressed. Similarly, the four engagement grooves 111 in FIG. 12B can be machined simultaneously with two of the two processing tools T, T so that their axial directions are directed toward the central axis Ja of the key body 110, thereby suppressing deflection of the key body 110 during machining.

[0068] When machining three or more engagement grooves 111, three or more machining tools T may be used and advanced simultaneously toward the central axis Ja of the key body 110 of the unlocking key 100 to perform the machining.

[0069] 14A and 14B may be used for the engagement groove 111 of the key body 110. This allows the driving end 243 of the cylinder lock 1 to be smoothly introduced and fitted into the engagement groove 111 of the key body 110 when the unlocking key 100 inserted into the keyhole 21 is turned. This improves the operability of the unlocking key 4100.

[0070] 14A and 14B is formed by a tapered surface that widens the groove width of the engagement groove 111 toward the tip of the key body 110. The specific shape of the wide portion 111a is not limited to a tapered surface, and the wide portion 111a may have any shape as long as it widens the groove width of the engagement groove 111 toward the tip of the key body 110. As shown in FIGS. 14A and 14B, the engagement groove 111 may have a tapered surface 111b that widens the groove depth of the engagement groove 111 along the radial direction of the key body 110 toward the tip of the key body 110.

[0071] 15 shows a door 200, which is a fixture equipped with the cylinder lock 1 of the locking device shown in this embodiment. The door 200 is placed openably and closably in a door opening 300 in a building frame. The door 200 has, on the door end side, a handle 201 for opening and closing the door 200, and a pair of cylinder locks 1 disposed above and below the handle 201. The door 200 is used, for example, as a front door.

[0072] In this embodiment, a front door is shown as an example of a fixture to which the cylinder lock 1 is mounted, but the present disclosure is not limited to a front door and can be applied to any door or door requiring security, such as a back door, terrace door, gate, interior door, shutter, etc. Furthermore, the present disclosure can be applied to anything other than fixtures, as long as the cylinder lock 1 can be applied, such as a delivery box, locker, safe, or refrigerator. The present disclosure includes the following aspects of the locking device, fixture, and method for manufacturing an unlocking key.

[0073] <Aspect 1> A locking device comprising: a cylinder lock having an inner cylinder with a circular keyhole and an outer cylinder rotatably fitted to the inner cylinder; and an unlocking key having a cylindrical key body that can be inserted into the keyhole of the cylinder lock, wherein the cylinder lock has a convex portion at the rear end of the inner cylinder that protrudes fixedly into the keyhole, and the unlocking key has a concave portion at the tip of the key body that is recessed from the tip face of the key body to the outer periphery and can engage with the convex portion, wherein the tip face of the key body inserted into the keyhole abuts on the convex portion, thereby positioning the unlocking key in the axial direction, and when the unlocking key in the axially positioned state is rotated around the central axis of the cylinder lock, the concave portion and the convex portion engage with each other, so that a driving force when the unlocking key is rotated can be transmitted to the inner cylinder.

[0074] <Aspect 2> The locking device according to aspect 1, wherein the recess has a wide portion whose groove width increases toward the tip of the key body.

[0075] <Aspect 3> The locking device according to Aspect 1 or 2, wherein a plurality of the protrusions are provided on the inner cylinder, the plurality of protrusions being spaced apart at a predetermined angle along the circumferential direction of the inner cylinder and facing each other in the radial direction of the inner cylinder.

[0076] <Aspect 4> A locking device according to any one of Aspects 1 to 3, wherein a rear end of the inner tube has a drive pin with the protrusion at its tip, the drive pin is disposed so as to penetrate the inner tube in the radial direction, and has a raised portion facing the outer peripheral surface of the inner tube on the end face opposite the raised portion, and the raised portion is in point contact with the inner peripheral surface of the outer tube.

[0077] <Aspect 5> The locking device according to any one of Aspects 1 to 4, wherein a drive pin is provided at the rear end of the inner tube, the drive pin having the protrusion at its tip and a portion adjacent to the protrusion that has a diameter larger than the outer diameter of the protrusion, the protrusion being formed in a cylindrical shape with a circular groove on the inside.

[0078] <Aspect 6> A fitting comprising the cylinder lock of the locking device according to any one of aspects 1 to 5.

[0079] <Aspect 7> A method for manufacturing an unlocking key having a cylindrical key body with a plurality of recesses at the tip end of the key body, spaced apart at a predetermined angle along the circumferential direction of the key body, and recessed from the tip surface to the outer circumferential surface of the key body, wherein the plurality of recesses are simultaneously machined using a plurality of processing tools that are spaced apart at a predetermined angle along the circumferential direction of the key body.

[0080] <Aspect 8> The method for manufacturing an unlocking key according to Aspect 7, wherein the plurality of processing tools are advanced simultaneously toward the central axis of the key body to process the plurality of recesses.

[0081] DESCRIPTION OF SYMBOLS 1 Cylinder lock, 2 Inner cylinder, 20a Outer peripheral surface of inner cylinder, 21 Keyhole, 24 Drive pin, 242 Small diameter portion (portion with a larger diameter than the outer diameter of the drive end), 243 Drive end (convex portion), 244 Groove portion, 245 Raised portion, 3 Outer cylinder, 30b Inner peripheral surface of outer cylinder, 100 Unlocking key, 110 Key body, 110a Tip surface of key body, 110b Outer peripheral surface of key body, 111 Engagement groove (concave portion), 200 Fitting, 111a Wide portion, J Central axis of cylinder lock, Ja Central axis of key body, T Processing tool

Claims

1. A locking device comprising: a cylinder lock having an inner cylinder with a circular keyhole and an outer cylinder that rotatably fits into the inner cylinder; and an unlocking key having a cylindrical key body that can be inserted into the keyhole of the cylinder lock, wherein the cylinder lock has a convex portion at the rear end of the inner cylinder that protrudes fixedly into the keyhole, and the unlocking key has a concave portion at the tip of the key body that is recessed from the tip face of the key body to the outer periphery and can engage with the convex portion, wherein the tip face of the key body inserted into the keyhole abuts on the convex portion, thereby positioning the unlocking key axially, and when the unlocking key in the axially positioned state is rotated around the central axis of the cylinder lock, the concave portion and the convex portion engage, so that a driving force when the unlocking key is rotated can be transmitted to the inner cylinder.

2. The locking device according to claim 1, wherein the recess has a wide portion whose groove width increases toward the tip of the key body.

3. A locking device as described in claim 1 or 2, wherein the inner tube is provided with a plurality of protrusions, and the plurality of protrusions are arranged at predetermined angles apart along the circumferential direction of the inner tube.

4. A locking device as claimed in any one of claims 1 to 3, wherein the rear end of the inner tube has a drive pin with the protrusion at its tip, the drive pin is arranged to penetrate the inner tube in the radial direction and has a raised portion facing the outer circumferential surface of the inner tube on the end face opposite the protrusion, and the raised portion is in point contact with the inner circumferential surface of the outer tube.

5. A locking device as claimed in any one of claims 1 to 4, wherein the rear end of the inner cylinder has a drive pin with the protrusion at its tip and a portion adjacent to the protrusion that has a diameter larger than the outer diameter of the protrusion, and the protrusion is formed in a cylindrical shape with a circular groove on the inside.

6. A fitting provided with the cylinder lock of the locking device according to any one of claims 1 to 5.

7. A method for manufacturing an unlocking key having a cylindrical key body with a plurality of recesses at the tip thereof, spaced apart at a predetermined angle along the circumferential direction of the key body, and recessed from the tip surface to the outer peripheral surface of the key body, wherein the recesses are simultaneously machined using a plurality of processing tools that are spaced apart at a predetermined angle along the circumferential direction of the key body.

8. A method for manufacturing an unlocking key as set forth in claim 7, wherein the plurality of recesses are machined by simultaneously advancing the plurality of processing tools toward the central axis of the key body.

Images