Abstract: A foldable card includes first and second sections, each defining a base and a layer of a blade of a key extending therefrom; and a hinge interface connecting the bases of the first and second sections, wherein the first section is configured to fold over the second section at the hinge interface so that a top surface of the first section is against a bottom surface of the second section and each of the layers of the blades align to form the blade of the key, and the first and second sections are configured to fold at the hinge interface into a storage position to form a collective flat surface.

Abstract: A lock and key combination that uses a key device which includes a shaft portion, and at least one movable key combination element which is retained within the shaft portion and which includes first and second portions adjacent one another, the first portion of the at least one movable key combination element being located along on the shaft portion and the second portion of the at least one movable key combination element being located offset to the first portion.

Abstract: A key blank comprises a shaft and a head connected to the shaft, the shaft including first and second surface that are oppositely facing, wherein the surfaces are configured to include combination elements to operate a lock and a pair of coaxial operating elements, wherein one element of the pair is operative from the first surface of the shaft and the other element of the pair is operative from the second surface of the shaft, and wherein at least one of the operative elements is a resilient element mounted inside a bore provided in the shaft, wherein the resilient element is operative to exert a compressive force on a pin mechanism of the lock in response to the operative engagement and thereby release the pin mechanism from a lock position, without requiring any pressure on the coaxial element on the other side.

Abstract: The present invention is directed to key assemblies and their mating locks, and more particularly, to keys with mutually compressible, actuating elements capable of being continuously positioned axially within apertures in a key blade.

Abstract: A key for opening multiple axial pin locks has a base member with an indexing element and a number of lock pins, configured to match the keyways of the locks. The key has a microprocessor with access to information on the pin configuration for each lock to be opened, and the lock pins are selectively positioned along the base member to match the configuration of a key for a particular lock in response to the user entering an identification code for that lock. The lock pins can slidably engage recessed tracks in the base member, which serve to direct the lock pins parallel to an axis of the base member. A pin latching mechanism can be provided to secure the lock pins in the desired position.

Abstract: A key device for use with more than one lock, the key device including a shaft portion, and at least one movable key combination element retained within the shaft portion and including first and second portions adjacent one another, the first portion of the at least one movable key combination element being located along on the shaft portion and the second portion of the at least one movable key combination element being located offset to the first portion.

Abstract: A key mechanism that makes it possible to fix the key inside the cylinder bolt lock outphased from the original combination, thereby preventing the cylinder of the bolt lock from turning. The security of the key mechanism is also enhanced as a cylinder tumbler engages within a slot of the key blade and the key cannot then be expelled from the cylinder bolt lock. Therefore, it is impossible to insert another key or picklock from the other side of the cylinder bolt lock.

Abstract: The present invention is directed to key assemblies and their mating locks, and more particularly, to keys with mutually compressible, actuating elements capable of being continuously positioned axially within apertures in a key blade.

Abstract: A lock and key mechanism reduces exposure to lock picking by including an extension into a key slot to receive and conceal tapered end portions of key pins. The only portions of key pins exposed in a key slot are cylindrical portions that are difficult to move from a resting position. A key includes a beveled leading edge and a spring-loaded pin activation element at the leading edge of the key. As the key is inserted into the key slot, the spring-loaded pin activation element is compressed to permit entry into the key slot. As the pin activation element reaches a pin, an aperture in the extension allows the spring-loaded pin activation element to move toward the key pin and move the key pin from its resting position. In this activated position, the tapered end portion of the key pin is exposed for further activation by the beveled leading edge of the key. The process is repeated until the pin activation element engages and activates each successive key pin and allows full insertion of the key.

Abstract: An article including a key comprising a key head that slides along a key shaft, said key head being affixable to said key shaft with a fastener.

Abstract: There is provided a lock device which is adapted to hold a lid member 3 with a lock 8 at a counterpart of a main body 1 in a closed state, which comprises an operating button for an unlocking operation 9; a slidable engagement member 11 having an engageable portion 14, the engageable portion being configured to be selectively brought into engagement with and out of engagement with the main body 1; and a coupling member 20 configured to interlock the operating button 9 and the engagement member 11 with a locking operation and the unlocking operation applied to the lock 8 so that the operating button 9 and the engagement member 11 are set in an interlocked state by the unlocking operation and are set to be free of the interlocked state by the locking operation; whereby the engagement member 11 is slid through the coupling member 20 to bring the engagement member 14 out of engagement with the main body 1 so as to be switched to an open state by operating the operating button 9 when the lock 8 is set in an unlock

Abstract: A master key includes a key base having a key handle, a fixing seat and a sleeve, all of which are connected to each other integrally. The fixing seat has a plurality of angularly spaced apart spring holes having respective key springs. A key tube includes a large cross-section tube section inserted into the sleeve, and a small cross-section tube section fixed to the fixing seat. The large tube section includes a plurality of angularly spaced apart long and short grooves. The long grooves are aligned with the respective spring holes to receive slide pieces, and the short grooves have respective shoulder faces. A tubular lock to be used with the master key is also disclosed.

Abstract: A lock has a flat key having a flat blade extending along a key axis and having an axially extending edge formed to each side of a central axially extending key plane with a pair of axially extending inner edge surfaces flanking the key plane and each formed with a plurality of bits offset transversely at different spacings from the key axis. The bits on one side of the key plane are offset axially to the bits on the other side of the key plane as described above. A barrel having an inner surface centered on a lock axis holds a plug rotatable about the lock axis in the barrel, bisected by a plug plane including the lock axis, and formed with an axially extending and open key hole adapted to receive the key with the axes coaxial and the planes coplanar. A respective set of axially spaced tumblers is dis-placeable in the plug to each side of the plug plane parallel to the plug plane. The tumblers of one of the sets engage the key in the hole at locations offset axially from the tumblers of the other set.

Abstract: A rotation restricted barrel lock and key includes a rotationally actuated barrel lock and a key for opening the lock. The key comprises a lock engaging portion rigidly attached to a handle, and a sleeve rotatably mounted on the handle shaft. The sleeve may slide axially along the shaft within preset limits. Lock actuation is characterized by rotation of the lock engaging portion of the key relative to the lock. During actuation of the lock, a set of prongs on the sleeve engages a complementary set of notches on the barrel lock, thereby non-rotatably coupling the barrel lock to the sleeve. By grasping the sleeve, the user can prevent rotation of the lock while turning the key handle, and thus actuate the lock.

Abstract: A keyway plug that provides a means for preventing the correct key from opening a tumbler lock, including a plug and an extractor. The plug fits into the keyway to block complete insertion of a key. An arm extends from the tip of the plug across the tumblers, but is short enough so that the outermost tumbler drops to hide the plug. The extractor includes a narrow finger, the end of which pushes the innermost part of the plug upwardly, while the tumblers push the outermost part of the plug downwardly. A chamfer at the outer end of the plug arm pushes the outermost tumbler up out of the way so the plug can be removed. The upper edge of the finger includes a hook that mates with a matching notch in the lower edge of the plug arm. As the extractor is removed, the hooks and notch interlock, pulling the plug from the keyway.

Abstract: A keyway plug that provides a device for preventing the correct key from opening a double-sided tumbler lock, including a plug and an extractor. The plug fits into the keyway to block complete insertion of a key. In one embodiment, a pair of arms extend from the tip of the plug across both rows of tumblers, but is short enough so that the outermost tumblers drop to hide the plug. In the second plug embodiment, the outermost tumblers drops into a notch in the arms to prevent the plug from going too far into the keyway. Alternatively, only one arm has a notch. The extractor includes a narrow finger, each edge of which include a hook that mates with a matching hook in the inner edge of each plug arm. As the extractor is removed, the hooks interlock, causing the plug to be removed.

Abstract: A tool is disclosed for opening tubular locks in which a tubular key is receivable. The tool includes a plurality of probes that are releasably retained and secured in a given position to align the shear points in the lock in an opening position. The probes can be ergonomically and individually manipulated and have a course and a fine adjustment, such that the shear point of each tumbler can be easily and efficiently determined. Once the shear point is determined, the probe may be fixed in the position to maintain each tumbler driver.

Abstract: The method and apparatus for picking a lock which utilizes a single blade or pair of elongated thin, rigid, interchangeable blades which are to be inserted within the keyway of the lock. Each of the blades have an upper hiatused surface and can have an off-center sharpened edge so that the sharpened edge will contact the cylindrical lock pins of the lock spaced from the center of each of the lock pins. The off-center sharpened edge could be formed by beveling the side of the blade or by making a cut-out in the blade. The hiatused surface of the blades cause the “V” shaped tips of the cylindrical lock pins of the lock to move lineally with the sharpened edge causing the lock pins to pivot. Instead of a hiatused surface, there could be used one or more deflectable members, tufts of bristles or a brush. The blades are to be driven in a reciprocal manner with one blade moving in and the opposite blade moving out.

Abstract: The method and apparatus for picking a lock which utilizes a single blade or pair of elongated thin, rigid, interchangeable blades which are to be inserted within the keyway of the lock. Each of the blades have an upper hiatused surface and can have an off-center sharpened edge so that the sharpened edge will contact the cylindrical lock pins of the lock spaced from the center of each of the lock pins. The off-center sharpened edge could be formed by beveling the side of the blade or by making a cut-out in the blade. The hiatused surface of the blades cause the lock pins of the lock to move lineally with the sharpened edge causing the lock pins to pivot. Instead of a hiatused surface, there could be used one or more deflectable members, tufts of bristles or a brush. The blades are to be driven in a reciprocal manner with one blade moving in and the opposite blade moving out.

Abstract: The method and apparatus for picking a lock which utilizes a single blade or pair of elongated thin, rigid, interchangeable blades which are to be inserted within the keyway of the lock. Each of the blades have an upper hiatused surface and can have an off-center sharpened edge so that the sharpened edge will contact the cylindrical lock pins of the lock spaced from the center of each of the lock pins. The off-center sharpened edge could be formed by beveling the side of the blade or by making a cutout in the blade. The hiatused surface of the blades cause the lock pins of the lock to move lineally with the sharpened edge causing the lock pins to pivot. Instead of a hiatused surface, there could be used one or more deflectable members, tufts of bristles or a brush. The blades are to be driven in a reciprocal manner with one blade moving in and the opposite blade moving out.

Abstract: A lock includes a case having a shield, a locking member housing contained in a first chamber of the case and protected by the shield, a locking member contained in the locking member housing, a locking rod also contained in the first chamber of the case and moved by the locking member in locking and unlocking, and a deadbolt having a press portion and a rod portion with an annular groove for the end of the locking rod to engage in for locking. The locking member has a single or a double pin tumbler locking mechanism, or a disc tumbler locking mechanism.

Abstract: A keyway plug that provides a means for preventing the correct key from opening a tumbler lock, including a plug and an extractor. The plug fits into the keyway to block complete insertion of a key. In one embodiment, an arm extends from the tip of the plug across the tumblers, but is short enough so that the outermost tumbler drops to hide the plug. In the second plug embodiment, the outermost tumbler drops into a notch to prevent the plug from going too far into the keyway. The extractor includes a narrow finger, the upper edge of which includes a hook that mates with a matching hook in the lower edge of the plug arm. As the extractor is removed, the hooks interlock, causing the plug to be removed.

Abstract: A key blank including a generally elongate shaft portion defining a key combination surface adapted to have formed thereon key cuts which define a key combination, the key blank including a movable pin element retained within the elongate shaft portion, the movable pin element being displaceable in a single direction, outwardly from the key combination surface.

Abstract: A key blank including a generally elongate shaft portion defining a key combination surface adapted to have formed thereon key cuts which define a key combination, the key blank including a movable pin element retained within the elongate shaft portion, the movable pin element being displaceable in a single direction, outwardly from the key combination surface.

Abstract: A rekeyable look includes at least one chamber housing a tumbler pin stack having a master pin disposed between the driver pin and the bottom pin. The bitting of a change code key inserted in the keyway displaces the tumbler pin stack containing the master pin such that the interface between the master pin and the bottom pin is placed on the shear line defined by the cylinder shell and plug. Rotation of the change code key aligns a first slot on the change code key with the master pin wherein the master pin is received by the first slot. The master pin is carried with the change code key on removal of the key from the keyway. A replacement master pin disposed in the first slot is inserted into the keyway with the change code key. Rotation of the change code key aligns the replacement master pin with the drive pin.

Abstract: A key operating mechanism is embodied in an elongate housing having an axially disposed shaft defining a helical groove. A shaft end is provided with a key to which rotation is imparted by an actuator slidably disposed on the shaft. A drive member of the actuator cooperates with the helical groove in the shaft to impart rotation to the latter and may serve as a detent to prevent actuator movement. Spring elements, oppositely disposed from the actuator, serve to return the actuator to a neutral or static position wherefrom rotation in either direction may be imparted to the shaft. A thumb operated control button of the actuator slides within a housing defined slot during operation of the mechanism.

Abstract: A safety lock and key includes a cylindrical stator and rotor having conventional spring-loaded moving rotor pins and moving stator pins. A first rotor pin/stator pin combination is at substantially 45 degrees to a first face of the key while a second rotor pin/stator pin combination is substantially perpendicular to a second face of the key on the opposite side. The centerlines of the rotor pin/stator pin combinations pass through the center of rotation of the rotor. A housing in the key contains a moving element and emerges from the first face of the key inclined at the same angle as the first rotor pin/stator pin combination. The housing also emerges from the second face of the key through a tapered bore that receives the second rotor pin/stator pin combination. A tapered head of the second rotor pin engages a rear portion of the moving element in the housing, thus engaging the moving element with the first rotor pin/stator pin combination.

Abstract: A key blank including a generally elongate shaft portion defining a key combination surface adapted to have formed thereon key cuts which define a key combination, the key blank including a movable pin element retained within the elongate shaft portion, the movable pin element being displaceable in a single direction, outwardly from the key combination surface.

Abstract: An additional tumbler (10) is disposed in the rotary lock cylinder, which is aligned by means of a control element (19) disposed in the key (16). A blocking element (6) is provided in the stator (2) at a distance from this tumbler (10) which, in a set rotational position of the rotor (3), radially displaces the control element (19) with the core pin (13) of the additional tumbler (10) against a restoring force.

Abstract: A security combination key is provided, which consists of a hollow housing having a removable cover plate. An elongated guide member having an open track therein and a ward groove on a side thereof, extends from one side of the hollow housing. A plurality of blades having serrations extend in parallel relationships from within the hollow housing into the track of the guide member with the serrations exposed in the track. An apparatus is for sliding the blades in the track of the guide member, to form various combinations with the serrations to match up with pin tumblers in specific locks. A device is for locking the blades in a stationary position in the track of the guide member. The guide member having the ward groove can be inserted into a keyway having a compatible set of ward ridges in a cylinder of the lock, allowing the serrations of the blades to properly position the pin tumblers to permit operation of the lock.

Abstract: A side bar lock decoder has a pair of guide plates laminarly arranged between a pair of side plates. Key portions of the plates have notches spaced for alignment with the lock wafers. Narrow passages between the guide plates extend from each of the notches to the edges of the base portions of the plates at approximately normal fingertip positions when the base portions are hand held. Wires slidably disposed in each of the passages extend from an outer end of each of the notches beyond the grip edges. One end of the wires abuts one of the wafers when the wafers and the notches are aligned. Springs, bias each of the wires toward a threshold reference position within the notches. Plungers, one connected to each of the wires, extend beyond the grip edges, are independently biased away from their respective edges by the springs. One or more housings secured to the laminar plates have at least one chamber therein for guiding the movement of each of the plungers during manipulation.

Abstract: A universal lock and key assembly in which the lock is re-keyable and the key is also changeable. The key has a shank portion having a longitudinally extending tooth slot in its top surface. A plurality of teeth have their bottom ends inserted into the tooth slot in any desired sequence to give a predetermined profile to the teeth of the key. The bottom pin cylinder of the lock has mating bottom pins for each of the respective teeth. These are then arranged in a coordinated sequence in the bottom pin cylinder of the lock. The structure of the system allows an individual to change both the configuration of the key and also the mating structure within the lock so it will be operable.

Abstract: A master tubular key co-operating with a conventional lock having a tumbler consisting of a first section rotating in the lock and having a first group of tunnels through which a group of first pins being different in length are received and a second section being fixed in the lock and having a second group of tunnels corresponding to the first group of tunnels and receiving springs and a group of second pins is disclosed. The master key has a group of springs which are much stronger than those in the lock and a plurality of strips. The springs urge the strips to force the group of first pins to keep the group of second pins completely in and the group of first pins completely off the second group of tunnels, thereby allowing the first section to rotate relative to the second section.

Abstract: An apparatus for determining lengths of locking elements in locks including a key head and wires maintained on the key head and extendable into the lock cylinder for measuring lengths of the lock pins. The distance that the wires will go into the depth of lock can be used to determine the depth of the furrows or the cuts of the needed key. The advantage of this invention is that one can duplicate a key which has been lost, without damaging the lock, or moving it out of the door. In addition to that this mechanism is also used as a "lock-picker" in order that one can lock or unlock a door when the keys have been lost. The invention operates in two different ways and for two different purposes. The first one is to duplicate a key which has been lost. The second one is to lock or unlock a door for different reasons, e.g. when the key has been lost, or when it is still inside the car or the house while the door is still locked.

Abstract: A key for a cylinder lock has a relatively slender profile region and a bitting region of greater thickness and a generally cylindrical configuration with or without longitudinally-extending flats. The bitting recesses can be provided round this bitting region and axially therealong and the profile region can be formed with grooves milled in its parallel flanks to increase key variability.

Abstract: A rekeyable lock includes a false bible which houses a retainer pin, the retainer pin engaging the lock core. The lock core has a pin tumbler located to selectively engage the retainer pin so as to cause disengagement thereof from the core. The false bible is not physically attached to the core and is configured to match the operating environment.

Abstract: The keyway of an automobile ignition lock can be protected by a key-shaped element which is secured by a combination lock to substantially preclude tampering with the automobile ignition lock. The guard device can be removed from the ignition lock keyway upon setting of the combination lock dials to the release position, and the regular ignition key can then be used with the ignition lock.

Abstract: A barrel lock and a key for locking and unlocking the barrel lock. The lock has a hollow barrel with a plunger that reciprocates within the bore of the barrel. The plunger is urged forwardly by a bottom spring, and a deterrent ring is urged forwardly against the plunger by a top spring. The plunger has a shallow axial blind bore at its rear end and the deterrent ring has a central aperture, the diameter of the plunger bore being larger than the diameter of the ring aperture.The key has four elongated outer expanding fingers and an inner expander rod. The expanding fingers are sized and shaped so that they can pass entirely through the central aperture of the deterrent ring. When the the key is inserted into the barrel lock and the key handle is operated, the fingers radially expand and grip the inner surface of the lock plunger blind bore. As the handle is operated further, the expanding fingers longitudinally retract and draw the plunger rearwardly permitting the lock to unlock.

Abstract: A key comprises a key body provided with at least one translatably movable plunger able to be displaced in a housing provided in the key, the plunger being intended to co-operate with a positioning member provided in the recess of a rotor so as to project from its recess and to push a movable pin of the rotor into a position permitting rotation of the barrel rotor relative to the stator. The key comprises in its head a constricted zone, and the recess of the movable plunger is provided in this constricted zone.

Abstract: A combination key includes a hollow head, a hollow stem connected to the head and a plurality of teeth mounted on racks longitudinally movable in the head and stem. The racks are in meshed engagement with toothed control wheels which are mounted in the head and emerge partially to the outside. The control wheels are located in the head next adjacent the stem. The length of the head is at least equal to the length of the stem so that the racks can be accommodated in the head when the teeth are in a position of maximum retraction.

Abstract: A picking tool adapted to open a cylinder lock of the axial pin tumbler type having its tumblers arranged in a coplanar configuration, includes a planar torquing core insertable into the lock keyway in a longitudinal direction, a plurality of longitudinal guideway channels formed on opposing faces of the core, and respective tumbler probes longitudinally reciprocable in the channels. A holder, which acts as a handle for manipulating the picking tool, also serves as a housing surrounding the core and the probes. The holder is formed with a pair of radial openings in opposite sides thereof which receive respective brake segments for exerting a frictional drag on the probes. An adjustable hoop clamp surrounds the brake segments for manually adjusting the frictional drag, so that the proper tumbler displacement action can be achieved. Setscrews are threaded into the body of the holder for clamping the probes in their final tumbler-displacing positions.

Abstract: A combination key permitting the opening of various different locks with a single key. The combination key has a hollow stem with longitudinally extending slots in which a plurality of teeth can be moved in longitudinal direction. A control mechanism arranged within the key facilitates the movement of the teeth, so that the relative positions of the teeth can be adjusted in accordance with the respective lock to be opened.

Abstract: A high security lock and a high security key for locking and unlocking said lock. The lock has a resilient O-ring seated in the bore of a hollow plunger and a retainer sleeve fixed in the bore of the hollow plunger and bearing against the rear surface of the O-ring. A center pin with an enlarged forward head extends rearwardly through the bore of the plunger, the O-ring gripping the periphery of the center pin and yieldably resisting center pin reciprocal movement within the plunger bore. The key has elongated outer expanding fingers and an inner coaxially arranged center pin. When the key is fully inserted into the lock and the key handle is operated, the expanding fingers are initially radially expanded to grip the inner surface of the lock plunger bore, and are then longitudinally retracted to draw the plunger rearwardly. Simultaneously, the key center pin is prevented from retracting and holds the lock center pin stationary permitting the lock to unlock.

Abstract: A locking device includes a key and a reading device. The key has a grip portion and a plurality of information carrier parts attached to the grip portion. The information carrier parts determine the locking code for the key. Each information carrier part is arranged to receive an information element and the carrier parts are adjustably positionable for disposing the information elements into a predetermined angular pattern. The reading device is arranged to read the locking code on the key and to compare it with a predetermined locking code for operating a lock. The information carrier parts are mounted on a member extending axially from the grip portion of the key. The carrier parts are angularly adjustably positionable about the axis of the member. The reading device contains elements for the detecting the presence or absence of the information elements in predetermined angular positions.

Abstract: The invention relates to a cylinder-lock having a flat key comprising a shank having at least one profile longitudinal groove extending from the end thereof to accommodate a rib in the key-channel of the cylinder-lock, said shank including fixed key bits adapted to index pin-tumblers in the cylinder-lock, said key including in the area of the wide side of the shank an additional movable key bit, said movable key bit being adapted to be controlled by a shoulder in the key-channel such that when the key is inserted it induces an auxiliary tumbler into a position which allows the cylinder core of the lock to be rotated.

Abstract: A key rotatably supported in a mounting and capable of being brought into engagement with a lock is held in the correct orientation for engaging the lock by being locked to the mounting by a retractable sleeve. Only when the mounting is brought into engagement with the lock does a portion of the lock engage the sleeve and push it back relative to the mounting to free the key for rotation. The mounting may be on a moveable part of a machine guard with the lock on a fixed part and controlling operation of the machine.

Abstract: A conventional tubular lock is made pick-resistant by the inclusion of a specially designed washer. The washer, which has a non-circular opening, is provided in the lock interior. The washer is preferably located between the helical compression spring and the rear face of the slidable plunger. The opening in the washer permits the insertion of a specially shaped expandable key, but does not permit the insertion of an old style expandable key, or a nail or other similarly round picking tool which has a sufficiently large diameter to wedge in the rear bore of the plunger. Therefore, the specially designed washer permits the lock to be opened only by an authorized key, but not by a nail or an unauthorized key.

Abstract: A key and a lock in a lock device having variable bit and ward patterns, respectively. The key has two pieces of bit members, one member of which is slidably fitted in a groove defined in the other member, while the other is stationary. The lock has ward members cooperative to those of the key, one of the ward members being movable, and the other being stationary. Thus, when the key is inserted into the lock and turned to its angularly displaceable end, and the position of the movable bit member of the key is varied, then the cooperative movable ward member in the lock may be moved thereby accordingly. The both movable members are then rigidly fixed in desired position. Thus, the lock can no longer be opened by a duplicate key or a master key. Alternatively, the two bit and ward members in a key and a lock may be so designed as to be movable, respectively.

Abstract: The disclosure relates to a key, which is dynamic, and a lock to be operated by the dynamic key. The key has a shaft with a key bit and a manual grip at opposite ends thereof. Mounted on the shaft is a bush spring loaded towards the key bit. A radial projection on the shaft engages a pair of mutually intersecting internal grooves in the bush, namely, one straight groove running parallel to the shaft axis and one annular groove encircling the shaft, so that when the bush is fixed the shaft can be constrained to move only parallel to its axis by engagement of the projection in the straight groove, and to move only rotationally about its axis by engagement of the projection in the annular groove. At its end facing the key bit the bush bears a number of pegs to be engaged in a corresponding number of holes in a fixed member of the lock. Located in and spring biased outwardly of these holes are two sets of pins.

Abstract: There is disclosed an emergency key mechanism on a cylinder lock with a double locking cylinder and a locking coupling axially moveably fitted thereon.