Abstract: A locking device for a tool includes a first component and a second component. The first component has a through hole, and an inner wall of the through hole is provided with a first engaging portion. The second component is selectively rotatably connected to the through hole and provided with a second engaging portion detachably engaged with the first engaging portion. The second component can move relative to the through hole to be switched between an unlocked position where the second engaging portion is disengaged from the first engaging portion and a locked position where the second engaging portion is engaged with the first engaging portion, so that the second component and the through hole are selectively rotatable relative to each other.

Abstract: The present invention provides a socket adapter 10 for an impact wrench to prevent a manipulator ring 60 from being intentionally slid, the socket adapter comprising: a main body 11 including a cylinder section 20 having an engagement hole 21 to be installed in an insertion square 90 of the impact wrench, a shank section 40 configured to attach or detach a socket 80, and a drum section 30 positioned between the cylinder section and the shank section; a ball locking mechanism 50 adapted to switch the socket between a locked state where the socket cannot be detached and an unlocked state where the socket can be attached and detached by protrusion and retraction of a ball 51 housed in the shank section; a manipulator ring 60 slidably fitted on the drum section in the axial direction and configured to control the protrusion and retraction of the ball; and a starting resistance imparting means 70 for increasing the starting resistance of the manipulator ring when the manipulator ring begins to slide from a locking

Abstract: A hand tool includes a first and a second handles, a rotating locking set, a fastening set, and a spring. The first and second handles include chamfered planes respectively. The rotating locking set includes a rotating block and a locking block. The fastening set includes a stud and a nut. The spring is mounted around the stud and elastically abuts against the rotating block. The first handle or the second handle drives the rotating block to disengage from the locking block when being pulled by an external force. The first handle and the rotating block rotate with respect to the second handle by the stud as the center point. The rotating block and the locking block are locked with each other after rotating a specific angle, so as to position the first handle and the second handle.

Abstract: A fastening tool including a bit holding unit configured to hold a driver bit so as to be rotatable and to be movable in an axis direction, a first drive unit having a first motor configured to rotate the driver bit held by the bit holding unit, and a second drive unit having a second motor configured to move the driver bit held by the bit holding unit along the axis direction.

Abstract: The invention is directed to an ergonomic tool holder, adaptable to a conventional pole and having a handle and a supporting base. These are coupled to an interconnecting unit in a non-permanent manner. The coupling of the handle to the interconnecting unit and the coupling of the supporting base to the interconnecting unit allows the tool holder to be assembled, having the handle in straight or multiple angled positions with regard to the supporting base and wherein the tool may be held and positioned along the X-X, Y-Y, or Z-Z axes. A given conventional utensil used in working activities such as painting or maintenance may be clamped and secured on the supporting base. Thus, the User may position such utensils in the tool holder straight or in the angled position at their convenience and may change such positions easily and quickly.

Abstract: An angle adjustment structure for pressing a hand tool comprising: a first handle, a second handle, a first spring washer, a second spring washer, a return spring, a first presser, a second presser, a first fastener and a second fastener. The first handle includes a contact sheet having a first thickness, a first toothed orifice. The second handle includes a groove having a second thickness, a second toothed orifice, a first fixing plate and a second fixing plate. A profile of the second toothed orifice is identical to a profile of the first toothed orifice. The return spring is defined on the first presser and the second presser. The first handle and the second handle adjust the angle when the first presser and second presser are pressed simultaneously, and being fixed by the first fastener and second fastener to avoid a removal.

Abstract: A screen protector installation tool for installing a screen protector on a screen of an electronic device, the tool includes a holding base and a pressing assembly, the holding base has a holding chamber for holding the electronic device and two guiding rails at two sides of the holding chamber, the pressing assembly includes a sliding element and a pressing element, wherein the sliding element includes two sliding portions which are respectively slidable along the two guiding rails, so as to allow the pressing element to move above the holding chamber to cause the screen protector positioned in the holding base to be installed on the screen of the electronic device.

Abstract: A compressor may include a shell assembly, a first scroll, a second scroll, a piston, and a piston-retention member. The piston engages the first scroll and may be partially received within a recess defined by the shell assembly. The piston and the shell assembly may cooperate to define a pressure chamber. The pressure chamber may be in selective fluid communication with a source of working fluid to control movement of the piston relative to the shell assembly. The piston-retention member may be mounted to the piston and selectively engage a rotationally fixed structure. The piston-retention member allows rotation of the piston relative to the first scroll in a first rotational direction and restricts rotation of the piston relative to the first scroll in a second rotational direction.

Abstract: A flex head tool includes a first body and a second body and a. retaining device adapted to position the second body at various angular positions with respect to the first body. The retaining device includes a retainer and an actuator adapted to move the retainer in a first position and a second position. The retainer and the actuator respectively have a first interacting structure and a second interacting structure abutting each other. The second interacting structure has a first and a second position at which the first interacting structure respectively abuts when the actuator is at a first position and a second position. The first and the second positions of the second interacting structure are at different distances from the end of the actuator.

Abstract: The present invention relates to an open-close handheld apparatus and a method of adjustment of the angle between the handheld portions thereof. The open-close handheld apparatus includes a first member and a second member. The first member includes a first clamping portion and a first handheld portion. The second member includes a second clamping portion and a second handheld portion. The first clamping portion and the second clamping portion are rotatably and movably connected via a first axle pin. The first clamping portion and the second clamping portion open and close relative to each other, the plane in which the open-close path thereof is located is an open-close plane. The first handheld portion is rotatably connected to the first clamping portion. The plane in which the rotation path of the first handheld portion is located is the same as or parallel to the open-close plane.

Abstract: The invention is a hand tool with an operating head, which comprises: a main body having two parallel ears spaced apart at a front end; and a working head having a body; a column connected to one side of the body; another side of the body is provided with a pivotal block and two flaps to pivotally connect the two ears of the main body between the pivotal block and the two flaps respectively. The two flaps are capable of assisting in supporting outer sides of the two ears to relatively strengthen a structure of the ear, thereby enhancing a torsion exerted by the column on a workpiece, and enhancing durability and strength of the column.

Abstract: A rake device for cleaning rain gutters and roof valleys which includes a rake which is pivotally secured to an elongated support pole to enable the rake to be positioned in multiple positions with respect to the support pole to reach multiple portions of the rain gutter or the roof valley.

Abstract: An attachment assembly for being connected with a hand tool includes an active unit, a passive unit and a switching shaft. The active unit includes a front wheel, a middle wheel and a rear wheel are simultaneously rotatably connected in sequence. The passive unit includes a first wheel and a second wheel are simultaneously rotatably connected. The switching shaft pivotably connects the active unit and the passive unit, and switches the active unit and the passive unit being rotatable or not.

Abstract: An apparatus is provided for performing spinal surgery having a handle assembly, a screw guide, and a retractor. A shaft is provided with a handle, a neck portion and a connecting portion. The screw guide is provided with a connecting element coupled to the connecting portion of the handle assembly. A retractor for retracting tissue is coupled to the screw guide, wherein the neck portion of the handle assembly is provided with a spring loaded sleeve adapted to engage one of a plurality of holes positioned on a portion of the connecting element. The connecting portion is pivotably coupled to the connecting element.

Abstract: An adjustable dent removal tool may include a handle coupled to a dual adjustment system, the dual adjustment system may include a body secured to the handle. The body may include a plurality of first engagement teeth. A piston may be provided that may be movably coupled to the body, the piston may include a plurality of second engagement teeth, which may be selectively engaged with the first engagement teeth, thereby releasably locking the body to the piston. A lower body may be secured to the body. The lower body may include a tool receiver. A tool shaft may be provided that may be releasably locked to the lower body in more than one position.

Abstract: A wheel brush and lug nut cleaner having a handle with a rear portion and a front portion operably configured to pivot with respect to one another utilizing a pivot pin with a plurality of grooves disposed along an external perimeter thereof. The rear portion has a spring-loaded release mechanism disposed therein and having an accessible release button and a lock tab in operational communication with the release button, wherein the accessible release button is operably configured to move the lock tab to a disengaged position and an engaged position with respect to the plurality of grooves, the disengaged position operably configured to enable pivoting of the front portion with respect to the rear portion and the engaged position operably configured prevent pivoting of the front portion with respect to the rear portion. The device also includes a brush head with a plurality of bristles disposed thereon.

Abstract: Various implementations include a handle attachment device. The device includes a body and a drive shaft. The body has a first portion and a second portion. Each of the first portion and second portion defines at least one fastener opening. Each of the at least one fastener opening defined by the first portion is alignable with one of the at least one fastener opening defined by the second portion. The first portion and the second portion are clampable on a crank when the device is in a mounted position. The crank has a crank rotational axis.

Abstract: A wrench with quickly angularly adjustable handle includes a head section and a handle. The head section and the handle are pivotally connected with each other via a first and a second pivoted ends, whereby the handle can be up and down swung relative to the head section. The first and second pivoted ends respectively have a first and a second end faces facing each other. The first end face is formed with an upper and a lower contact sections. The second end face is formed with an upper and a lower abutment sections. The lower abutment section abuts against the lower contact section as a lower dead end of angular displacement of the handle. The upper abutment section abuts against the upper contact section as an upper dead end of angular displacement of the handle.

Abstract: Examples of the present disclosure relate to ratchets and include ratchets having a positive stop ratchet mechanism which controls the movement of a pawl and/or pusher with various geometric configurations and using various materials.

Abstract: A hand tool includes a first body, a locking member and a second body. The first body has a function end, a pivotal hole, a first toothed portion, a first groove, a second groove and a first restriction groove. The locking member has a second toothed portion, a second restriction groove, a first connection portion, a restriction member, an engaging member and a resilient member. The second body has a third connection portion connected to the first connection portion to connect the first and second bodies. When the locking member moves to a first position, the engaging member is engaged with the first groove. The first toothed portion is engaged with the second toothed portion. When the locking member moves to a second position, the engaging member is engaged with the second groove. The first toothed portion is disengaged from the second toothed portion.

Abstract: An apparatus is provided for performing spinal surgery having a handle assembly, a screw guide, and a retractor. A shaft is provided with a handle, a neck portion and a connecting portion. The screw guide is provided with a connecting element coupled to the connecting portion of the handle assembly. A retractor for retracting tissue is coupled to the screw guide, wherein the neck portion of the handle assembly is provided with a spring loaded sleeve adapted to engage one of a plurality of holes positioned on a portion of the connecting element. The connecting portion is pivotably coupled to the connecting element.

Abstract: An angle adjusting device for a wrench contains: an operating handle, a connecting head, an accommodating cavity, and a driving member. The driving member has a toothed portion arranged in the accommodating cavity. The accommodating cavity has two orifices defined on two extending arms thereof, and the toothed portion has an aperture for corresponding to the two orifices, such that a coupling post is inserted into the two orifices and the aperture. The accommodating cavity also has a notch, and the connecting head has a trough accommodating a first resilient element and a pressing member. The notch accommodates a second resilient element and a retainer, the retainer has a cutout and an indentation defined on one side of the cutout. The pressing member has a small-diameter column extending outwardly from a central position thereof and a circular retaining tab arranged on a rear end of the small-diameter column.

Abstract: In one aspect of the disclosure, an apparatus for being coupled to a drive to rotate a first portion of an article relative to a second portion thereof is provided. A chassis includes a first slot and an engagement feature. An input is rotatably mounted to the chassis, and an annular output is rotatably mounted to the chassis and is rotatably coupled to the input. A collar, which includes a plurality of mating features complementary with the engagement feature, is configured to engage the drive. The annular output includes a wall and a second slot extending entirely through the full thickness and height of the wall.

Abstract: An angle adjusting structure of a ratchet wrench includes a shank, a driving head, a located member, a spring and a detent member. The shank includes a pivot socket and a limiting portion. The pivot socket has a first pivoting portion and a bottom surface, the limiting portion is adjoined to the pivot socket and includes a limiting hole. The driving head includes a second pivoting portion which is pivotally connected to the first pivoting portion and has a plurality of meshing teeth. The located member is slidably located on the bottom surface. The located member includes a plurality of engagement teeth and a sliding rail, the engagement teeth is for meshing the meshing teeth, the sliding rail is correspondingly located on an outside of the limiting hole. The spring is located in the limiting hole. The detent member is connected to the spring and the sliding rail.

Abstract: A pivot head wrench includes a handle, a head, a pivot pin, a linear motion mechanism and a lock mechanism. The pivot pin connects the handle and the head. The linear motion mechanism is disposed at the handle and includes a moving path, wherein the head is disposed in the moving path. The lock mechanism includes a groove and at least one protrusion, wherein one of the groove and the protrusion is disposed at the head while the other is disposed at the linear motion mechanism for engaging with each other, and the protrusion and the groove both are disposed in the moving path.

Abstract: A ratcheting device includes a handle member including a first end and an opposed second end, a ratchet head pivotably connected to the first end of the handle member, and a ring grip pivotably connected to the second end of the handle member.

Abstract: A wireless small motor driver, in which power consumption is decreased by adjusting a gear ratio, the efficiency of an operation is increased due to a high torque, and the safety of a worker at night is ensured using an illumination lamp. The wireless small motor driver includes a driver case inside of which a motor is provided. A driver bit has a predetermined length in a bilateral direction, the driver bit being replaceable, with one or both ends thereof conforming to the shape of a bolt, and has a fixing projection. A socket is coupled to an end portion of the driver case, the driver bit being fastened to the socket. A rotation reduction gear is coupled to the motor, the rotation reduction gear transmitting rotary force to the socket and increasing a torque. A USB and a battery for supplying uniform power to the motor are added.

Abstract: A wrench includes a first part having a first pivotal portion, a first recess and a first hole, a second part having a second pivotal portion, a second recess and a second hole, and a third part which is received in the first and second recesses. The third part has third, fourth and fifth holes, and a control slot. A control unit is connected to the third part and has four urging members, two first acting members and a second acting member. The urging members are located in the third and fourth holes, and engaged with the first and second holes to pivotably connect the first and third parts, and the second and third parts. The first acting members are located in the fifth hole. The second acting member is located in the control slot and controls the first acting members to contact and the urging members or not.

Abstract: A wrench including a handle having a first yoke at a first end and a first plurality of tool heads coupled to the first yoke at a first pivot axis, at least a first tool head of the first plurality of tool heads having a drive cavity. Each tool head of the first plurality of tool heads is pivotable about the first pivot axis independently of the other tool heads of the first plurality of tool heads.

Abstract: A foldable wrench includes a lever, a handle, a lock and a key. The lever includes two lugs each including an opening defined therein. The first lug includes teeth formed on the wall of the opening. The handle includes a lug including an opening defined therein and teeth formed on the wall of the opening. The lug of the handle is placed between the lugs of the lever. The lock includes teeth formed thereon. The lock is movable between a releasing position to engage the teeth of the lock with the teeth of the handle only and a locking position to engage the teeth of the lock with the teeth of the handle and the teeth of the lever. The key is rotatable on the second lug of the lever between a first position corresponding to the releasing position and a second position corresponding to the locking position.

Abstract: A wide-angled wrench includes a handle, a connector, and a tool head. The connector is provided with two mounting channels each provided with a receiving recess. The handle has a first pivot portion provided with a plurality of first positioning grooves. The tool head has a second pivot portion provided with a plurality of second positioning grooves. The wide-angled wrench further comprises two elastic plates mounted in the receiving recess of each of the mounting channels. Each of the elastic plates is provided with a positioning projection. The positioning projection of a first one of the elastic plates is positioned in one of the first positioning grooves of the handle. The positioning projection of a second one of the elastic plates is positioned in one of the second positioning grooves of the tool head.

Abstract: An adjustable driving tool includes a handle and a driving rod. The handle has a limiting portion disposed in the handle and a slot. The limiting portion has an inner space communicating with openings of a first sleeve portion and a second sleeve portion. The slot communicates with the inner space. The handle provided with a pin disposed through the inner space, and the first and second sleeve portions are disposed around the pin. The driving rod has a working end and a fixation end having an elongate through hole around the pin. The fixation end is disposed into the inner space through the slot. The driving rod is slidable relative to the pin, and the fixation end is controllably selectively inserted into the first sleeve portion or the second sleeve portion so that the driving rod is held.

Abstract: The present invention provides for a multi joint driving tool apparatus comprises a first elongated, a second connecting and a third members pivotally attached to one another and movable to create a plurality of configurations; the third member having a bit holding compartment with an opening for receiving a bit.

Abstract: A tool handle includes a first handle unit, a joint unit connected rotatably to the first handle unit and formed with a plurality of positioning grooves, a second handle unit connected co-rotatably to the joint unit, and a latch member inserted into the first handle unit and movable between a lock state, where two latching projections of the latch member engage two of the positioning grooves and the first and second handle units are non-rotatable relative to each other, and an unlock state, where the latching projections are disengaged from the two of the positioning grooves and the second handle unit is rotatable about the engaging block to permit adjustment of an orientation of the second handle unit relative to the first handle unit.

Abstract: In a multi-function tool structure, a body and a work rod are pivotally connected together and can form a folded and retracted state. Moreover, an elastically movable press button is disposed on the body and can link up a positioning pin movably inserted into the work rod. Thus, pressing the press button can release a lock between the work rod and the positioning pin so that the work rod is swingable, while releasing the press button can lock the positioning pin and the work rod together again. Thus, the work rod and the body can be folded and retracted to facilitate the storage and carrying. After the work rod is developed, it can form multiple included angles with respect to the body so that the requirements of different operation angles can be satisfied.

Abstract: An adjustable driving tool includes a handle and a driving rod. The handle has a limiting portion disposed in the handle and a slot. The limiting portion has an inner space communicating with openings of a first sleeve portion and a second sleeve portion. The slot communicates with the inner space. The handle provided with a pin disposed through the inner space, and the first and second sleeve portions are disposed around the pin. The driving rod has a working end and a fixation end having an elongate through hole around the pin. The fixation end is disposed into the inner space through the slot. The driving rod is slidable relative to the pin, and the fixation end is .controllably selectively inserted into the first sleeve portion or the second sleeve portion so that the driving rod is held.

Abstract: A positioning device for a hand tool includes a handle, a tool head, a positioning member and an adjusting member. The positioning member has a pusher and a spring. The adjusting member has a threaded portion1 extended therefrom and abutted against the pusher. An extending portion is extended from the threaded portion. A retaining portion is defined at one end of the extending portion. Therefore, when a user rotates the adjusting member, the retaining portion is restricted by the pusher for preventing the adjusting member being lost.

Abstract: The present invention relates to a hand tool having a pressing spring. The hand tool comprises a grip part and a tool part. The tool part comprises a tool rod, a tool rod pivot head, a pair of external fixing pieces and a pressing spring. The pair of external fixing pieces is pivotally connected to the tool rod pivot head. When the tool rod is rotated, a relationship between the tool rod and the pair of external fixing pieces is switchable to one of a collinear relationship or a vertical relationship thereof, and the tool rod is pressed by the pressing spring without being loose after switching. Accordingly, the present invention has advantages and effects of directly switching, firm and stable positioning and not easy to be loose, and so on.

Abstract: A wrench with quickly angularly adjustable handle includes ahead section and a handle. The head section and the handle are pivotally connected with each other via a first and a second pivoted ends, whereby the handle can be up and down swung relative to the head section. The first and second pivoted ends respectively have a first and a second end faces facing each other. The first end face is formed with an upper and a lower contact sections. The second end face is formed with an upper and a lower abutment sections. The lower abutment section abuts against the lower contact section as a lower dead end of angular displacement of the handle. The upper abutment section abuts against the upper contact section as an upper dead end of angular displacement of the handle.

Abstract: A handtool includes a first element and a second element. A pivot end of the first element is pivotably disposed on a pivot trough of the second element wherein the pivot trough having a lateral breach. The pivot end is able to slide in the pivot trough between a restriction position and a pivotable position along a longitudinal direction of the second element. When the pivot end is located at the restriction position, the pivot end is hindered by the bottom of the pivot trough so as to fail to pivot with respect to the pivot trough. When the pivot end is located at the pivotable position, the pivot end is away from the bottom of the pivot trough so as to be pivotable via the breach. As a result, the present invention is easy to bend for use.

Abstract: A wrench for applying torque to a fastener that may eliminate or reduce variations associated with off-axis torque application and/or application of force on the handle at a location other than the load position.

Abstract: A foldable wrench includes a lever, a handle, a lock and a key. The lever includes two lugs each including an opening defined therein. The first lug includes teeth formed on the wall of the opening The handle includes a lug including an opening defined therein and teeth formed on the wall of the opening. The lug of the handle is placed between the lugs of the lever. The lock includes teeth formed thereon. The lock is movable between a releasing position to engage the teeth of the lock with the teeth of the handle only and a locking position to engage the teeth of the lock with the teeth of the handle and the teeth of the lever. The key is rotatable on the second lug of the lever between a first position corresponding to the releasing position and a second position corresponding to the locking position.

Abstract: A pivot head wrench includes a handle, a head, a pivot pin, a linear motion mechanism and a lock mechanism. The pivot pin connects the handle and the head. The linear motion mechanism is disposed at the handle and includes a moving path, wherein the head is disposed in the moving path. The lock mechanism includes a groove and at least one protrusion, wherein one of the groove and the protrusion is disposed at the head while the other is disposed at the linear motion mechanism for engaging with each other, and the protrusion and the groove both are disposed in the moving path.

Abstract: A shifting device for a wrench tool contains: a tool head including a driving portion and an axial hole, and the axial hole having a plurality of inner teeth; a rotating rod including an axial peg extending outwardly to be fitted in the axial hole, and the axial peg including a first groove and a second groove communicating with the first groove; an engaging member received in the first groove and having a toothed section and a pushing section; a controlling member fixed in the second groove and having an abutting stem extending into the first groove, such that the controlling member pushes the pushing section so that the toothed section engages with the plurality of inner teeth; two elastic loops fitted on the axial peg of the rotating rod to push one end of the engaging member so that the engaging member moves back to an original position.

Abstract: An indexable tool includes a handle, an indexable tool body and a coupling subassembly. The coupling subassembly rotatably joins and selectively locks and unlocks the handle and the indexable tool body in rotatable relation to each other. The coupling subassembly includes a push button fixedly coupled to a push button cylinder, adjacently disposed first and second serrated inserts, a cap, a cap retention ring, a push button retainer clip and a spring. The cap is held in fixed position with the cap retention ring. The spring is biased to hold the coupling subassembly in a locked position to prevent relative rotation between the tool body and the handle. In an unlocked position the push button is pushed against the bias of the spring to slidably move the coupling subassembly into a position enabling relative rotary movement of the handle relative to the indexable tool.

Abstract: The present invention relates to a hand tool having a pressing spring. The hand tool comprises a grip part and a tool part. The tool part comprises a tool rod, a tool rod pivot head, a pair of external fixing pieces and a pressing spring. The pair of external fixing pieces is pivotally connected to the tool rod pivot head. When the tool rod is rotated, a relationship between the tool rod and the pair of external fixing pieces is switchable to one of a collinear relationship or a vertical relationship thereof, and the tool rod is pressed by the pressing spring without being loose after switching. Accordingly, the present invention has advantages and effects of directly switching, firm and stable positioning and not easy to be loose, and so on.

Abstract: A hand tool with an adjusting structure includes a handle having an assembling space, an axial hole opened at a bottom of the assembling space, a controlling set having an engaging member, the engaging member received into the axial hole, the engaging member having an engaging notch opened thereon, a head member having a pivoting portion defined at one end thereof, the pivoting portion received in the assembling space, a pivoting rod passing through the assembling space and the pivoting portion at one end of the handle, the pivoting portion having a plurality of ratch teeth defined thereon, the engaging member engages with one ratch tooth of the pivoting portion. Under this arrangement, when the user wants to adjust an angle between the handle and the head member, the user rotates the head member relative the handle.

Abstract: A foldable hand tool has a handle and a driving head. The handle has a driving head guide groove which extends along the handle and penetrates one side of the handle. A combined lug protrudes from an assembly end of the driving head and is fitted slidably with the driving head guide groove. The driving head is slidable along the driving head guide groove such that the driving head swings perpendicular to the handle. The hand tool can be positioned in a straight configuration or in a T-shaped pattern.

Abstract: A driver accessory includes a housing having a first housing portion and a second housing portion movable relative to the first housing portion, an input shaft at least partially received in the first housing portion and defining a first axis, and an output shaft at least partially received in the second housing portion and defining a second axis. The output shaft is supportable by the housing in a first position relative to the input shaft in which the first and second axes are substantially parallel, and in a second position relative to the input shaft in which the first and second axes are non-parallel. The driver accessory also includes a locking mechanism operable to secure the second housing portion relative to the first housing portion when the output shaft is in the first position and the second position relative to the input shaft.

Abstract: A hand tool with adjustable swing angle includes a first and a second ends connected with each other to contain an adjustable angle. The first end has an upper wall section having a first splined hole and a lower wall section having a through hole. An annular groove is formed on a circumferential wall of the through hole. The second end is formed with a second splined hole positioned between the first splined hole and the through hole. An engagement member having a bulged section is positioned in the splined holes. An elastic restriction ring is positioned in the annular groove and has at least two holding sections positioned in the through hole. When moving the engagement member up and down, the elastic restriction ring is expanded by the bulged section, permitting the engagement member to engage with both the first and second ends or only the second end.