Abstract: Normally, when assembling trucks to a skateboard, a screw and a nut are used to mount it to the skateboard. The assembly requires two tools, a screw driver and socket wrench, which are used to tighten the skate trucks to the board. The purpose of my invention is to eliminate the use of the socket wrench. Lockdown is a specially designed nut with an arrow like end that serves to keep the nut from rotating when tightening the skate trucks to the board, which eliminates the socket wrench. This is how the process works, the nut with the aid of its arrow like end, butts up against the truck and prevents it from rotating. Normally with a regular nut, you would need a socket wrench to keep the nut from rotating. With lockdown the process eliminates the need for a socket wrench thereby making the installation faster and efficient.

Abstract: There is provided a fastening device in which the tightening load at the engaged portion between the thread of a nut and the thread of a bolt can be made uniform along the length of the threads, the circumferential load distribution at the end of the engagement of the bolt can also be made uniform, and concentration of a stress in the vicinity of the beginning of the engagement can be reduced. The fastening device includes an object to be fastened, having a nut hole; a nut having, at one end, a female screw portion to be fitted in the nut hole and configured such that the center of gravity is located in the nut hole; and a bolt having, at one end, a male screw portion to be screwed into the female screw portion.

Abstract: A nut for a reinforcing bar capable of stably maintaining its screwed state with a reinforcing bar and enabling the reduction of its projecting portion from the end face of a structural body. The nut for a reinforcing bar (10) comprises a cylindrical body part (10a), a regular hexagonal flange (10b) formed at one end of the body part (10a), and a female screw thread part formed on the inner peripheral surface of the flange (10b). The body part (10a) is insertable into a through hole formed in a concrete block, and the female screw thread part formed on the inner peripheral surface of the body part (10a) can be screwed onto a male screw part formed on the outer periphery of the reinforcing bar inserted into the through hole. Three pairs of flat parts (10d) parallel with each other with respect to the center axis (X) of the body part (10a) are formed on the outer periphery of the regular hexagonal flange (10b).

Abstract: The present invention provides an improved shackle having particular utility in underwater salvage operations. the present invention discloses a shackle that has a generally U shaped body that is comprised of a bow portion and first and second spaced apart arms. Each arm has an end portion with an opening for receiving a shackle pin. The shackle pin is sized and shaped to simultaneously fit through the shackle pin openings, and end portion of the pin having external pin threads. A nut provides an internally threaded opening for engaging external threads of a shackle pin. The nut is rotatably mounted to a second end portion of the shackle body. The external pin threads of the shackle pin and the internal threads of the nut are engaged when the pin is connected to the nut by rotating the nut. The pin does not rotate relative to the shackle body, due to an elongated groove in the pin that travels on a key portion of the shackle body that is in one of the openings.

Abstract: The invention relates to a device (10, 30) which is used to produce a screw connection between a first component (14, 60) and at least one additional component (15, 70), by means of a fixing screw (12) or a fixing groove (50, 55) and a corresponding fixing element (16, 73). Said device (10, 30) comprises a rotationally mounted tool (11, 31), wherein the fixing screw (12) and/or the fixing groove (50, 55) is maintained in a manner that prevents it from rotating and in an axially fixed manner and wherein the head (20) of the fixing screw (12) and/or the fixing groove (50, 55) is maintained at a distance (S) in relation to the first component (14, 60) as long as both components (14, 60; 15, 70) are joined together. According to the invention, at least one energy accumulator (18, 48) is provided between the tool (11, 31) and the first component (14, 60).

Abstract: Disclosed therein are a coupling boss and a method for fabricating a coupling boss, that a collar part is formed through a collar drawing process using a metal plate material, and then, a body part of the coupling boss is firmly combined to a substrate plate through processes of deep drawing, tapping, cleansing, plating and iron coining in order, thereby maximizing competitive power in price, miniaturizing the coupling boss in size, and maximizing tensile strength, compression strength, and surface roughness. In this instance, a more stable material thickness can be kept by performing a collar drawing process or a curling process when a screw part of the coupling boss is formed.

Abstract: The invention relates to a wind turbine tower comprising a tower foundation, and at least two tower sections connected by numerous sets of connecting means positioned in close proximity of each other. The connecting means comprising at least one nut with at least one assembly opening for interacting with an assembly tool. The invention also relates to a method for assembling a wind turbine tower and a method for manufacturing a nut of connection means for fixating a wind turbine tower including at least two tower sections.

Abstract: A fastener assembly includes a bolt having first and second ends and comprising a bolt head at the first end, a first shank portion having a smooth circumferential surface of a first diameter and a second shank portion coaxial with the first shank portion and of a second diameter smaller than the first diameter. At least a part of the second shank portion is externally screw threaded and the first shank portion is positioned between the bolt head and the second shank portion. A nut has first and second ends and includes a first bore extending from the first end of the nut and of a diameter greater than the first diameter for fitting over part of the first shank portion of the bolt, and, in the region of the second end, a screw threaded bore for screw threaded engagement with the screw threaded second shank portion, the screw threaded bore being coaxial with and leading into the first bore.

Abstract: An automotive audio bracket for mounting a vehicle component to an interior surface of the vehicle includes a first mounting surface oriented substantially perpendicular to the interior surface and adapted for attachment to a rigid support structure of the vehicle, and a second mounting surface oriented substantially perpendicular to the interior surface and adapted for attachment to the vehicle component. An elongated aperture extends through one of the first and second mounting surfaces, the aperture being elongated along an axis substantially perpendicular to the interior surface. A fastening mechanism is positioned within the aperture and connects the first mounting surface to the second mounting surface.

Abstract: A fastener in combination with a substrate wherein the fastener is affixed to the substrate in a manner that does not damage the substrate. The fastener comprises a barrel having an interior, an exterior, a first end portion, a second end portion, and an intermediate portion. The first end portion of the barrel includes a flange. The exterior of the barrel proximate the flange includes a gripping portion with a spline having at least 12 teeth. The interior of the barrel proximate the second end portion of the barrel includes a counterbore. The interior of the barrel proximate the intermediate portion is threaded. The second end portion of the barrel is flared. The substrate includes a cylindrically shaped bore extending therethrough. The barrel of the fastener partially resides in the bore of the substrate and the 12-toothed spline on the exterior of the barrel of the fastener engages the bore of the substrate and surrounding material with minimal deformation.

Abstract: The invention relates to a method for producing hollow body elements (200), for example, nut elements which are applied to components which are normally made of steel (280), in particular, for producing hollow body elements having an essentially quadratic or rectangular external profile (202). Said method consists of cutting individual elements of a profile in the form of a profile rod (1) or a winding after holes (204) have previously been stamped in the profile, a threaded cylinder (206) is subsequently, optionally, formed using a follow-on composite tool (10) which consists of several working stations. The invention is characterized in that a penetrating process and a punching process are carried out in the working station. The invention also relates to hollow body elements (200), components, follow-on composite tools (10) and rolling mills (600, 602).

Abstract: A fastener includes a fastener body with a peripheral surface that is configured to be received in a mold assembly. The body is divided into an encased portion and an exposed portion. The encased portion is configured to be surrounded by molding material. The exposed portion is configured to be void of molding material. A crush rib extends along at least a portion of the peripheral surface at an interface between the encased portion and the exposed portion.

Abstract: Methods and systems for a an integrated captive fastener system is provided. A system includes an integrated nut assembly configured to be tethered to a first structure, the nut assembly including at least one of a lock washer and a flat washer coupled to a nut using a retainer, and a bolt configured to be tethered to at least one of the first structure and a second structure, the nut assembly configured to be threadably couplable to the bolt.

Abstract: A self-attaching nut for installation in a panel by a plunger driven against the bottom face of the nut, the bottom face of the nut including parallel rails on opposed sides of a channel-shaped recess and a threaded bore through the recess, eliminating the requirement for a countersink in the bore at the bottom face and preventing tapping burrs from being driven back into the bore during installation.

Abstract: A threaded insert which has a cutting edge on its external surface. The cutting edge is configured to punch a hole in a workpiece while leaving a slug intact, still connected to the workpiece structure. The cutting edge is configured such that no backup die need be utilized to form the hole in the workpiece. The threaded insert includes an internal threaded portion, and a deformable side wall which is configured to deform upon installation of the threaded insert, to forming a blind-side bulb against the workpiece, and against the slug. The threaded insert is configured such that an installation tool can be threaded into the threaded insert, the threaded insert pierced through the workpiece. Then, the installation tool is actuated to cause the deformable side wall of the threaded insert to plastically deform and form the blind-side bulb.

Abstract: A nut includes a body, a centrally defined through hole defined through the body and an inner threading formed on an inner periphery defining the through hole. A wear resistant coating is coated on an outer periphery of the body and the inner periphery of the through hole such that load endurance of the nut is increased.

Abstract: A sealing member is composed of upper and lower holders which are molded members formed of rubber or resin. The upper holder has a stopper having a tubular shape with a flange inserted on its inner periphery. The lower holder has an inserted nut and outer threaded member on its inner and outer peripheries. In fixing a battery, after the outer threaded member of the lower holder is secured to a seat of a body frame by being screwed therein, the case is attached so that an expanded portion covers the lower holder, and then the upper holder is attached in a hole of the expanded portion. Subsequently, a bolt is presented through a battery holder, and is tightened by being screwed into the nut of the lower holder.

Abstract: A swivel nut comprising a body (10) having a threaded bore (130), the body comprising a ridge (11) which circumferentially extends about an outer surface, the body further comprising a first surface (12) which extends normal to a body bore centerline (CL), a tapered member (20) having a tapered surface (22) and a bore (23), the tapered member further comprising a second surface (23) which extends normal to the body bore centerline and which second surface cooperatively engages the first surface, the tapered member comprising a groove (21) which extends about an inner surface, and the groove cooperating with the ridge to connect the body and the tapered member while allowing the tapered member rotational movement with respect to the body.

Abstract: The disclosure relates to a corrosion resistant article comprising a metal body and a protective coating applied on at least one surface of said metal body, said protective coating comprising: (a) a zinc layer comprising metallic zinc; (b) a silicate layer comprising at least one silicate; and (c) a lubricant layer comprising at least one lubricant such as, for example, polyethylene wax. In particular, the disclosure relates to a corrosion resistant bolt and/or nut having a protective coating for use in motor vehicles. The protective coating is substantially free of chromates and phosphates and, hence, environmentally acceptable. The article has an excellent coefficient of friction, temperature resistance and anti-corrosion properties.

Abstract: A fastener, such as a housing, for mounting to a structure, such as a panel, that has an aperture formed therethrough. The fastener includes a shank member and an annular nut member that is configured to align coaxially with the shank member. The shank member is inserted through aperture in the structure and the nut member is placed on the shank member. Teeth on the radially outwardly facing surface of the shank member engage a pawl, such as one or more teeth, on the radially inwardly facing surface of the nut member to lock the nut member to the shank member. Removal of the nut member is effected by rotating the nut member to disengage the pawl from the teeth, thereby permitting longitudinal displacement of the nut member off of the shank member.

Abstract: A cage nut assembly includes a nut having a cylindrical portion extending from a plate portion. The nut is encaged in a cage such that the cylindrical portion extends through an aperture in the cage. The cylindrical portion of the nut is collapsible such that the nut collapses and provides a plurality of flanges upon an application of force. The flanges are folded or curved/mushroomed such that the plate portion of the nut is suspended within the cage so that the nut will not, or will minimally, stick to the cage or workpiece when coated with e-coat or ELPO. Upon torqueing a fastener into place, the flanges are bent up to allow the plate portion to interface with the cage or a workpiece to provide a solid joint.

Abstract: The preferred embodiment of a fastening system includes a self-piercing fastener having a thread-like pattern. In another aspect of the present invention, a fastener insertion machine employs an electromagnetic actuator without fluid actuation. A further aspect of the present invention uses a rotary-to-linear transmission within the machine to advance the fastener. In still another aspect of the present invention a self-piercing fastener is a clinch nut or a clinch stud.

Abstract: A threaded fastener capable of being reduced in size and weight. A pair of side wall surfaces of each of six radially outwardly projecting, torque transmitting portions lie on straight lines passing through the center line in a cross section perpendicular to the center line so as to transmit torque through the side wall surface, whereby the direction of a surface orthogonal force N applied to a force-applied point P by a wrenching tool coincides with the direction of an effective wrenching force F. This arrangement reduces an operation force required for rotating the wrenching tool and accordingly the load acting on each of the torque transmitting portions, in comparison with a conventional hexagonal head. That is, it is possible to reduce the diameter of the head portion of the threaded fastener and the size and weight of the head portion, while avoiding deformation of the side wall surfaces through which the torque is transmitted.

Abstract: A fastener assembly for making it easier to tighten and loosen the fastener in confined work spaces.

Abstract: A nut includes a bottom wall adapted to be connected fixedly to a printed circuit board, and an annular surrounding wall extending integrally from a periphery of the bottom wall away from the printed circuit board, having a threaded inner wall surface, and cooperating with the bottom wall to define a threaded blind hole for engagement with a bolt.

Abstract: A breakaway coupling for a light pole or the like is disclosed and is utilized on each of the anchor bolts of the foundation for the pole. Each of the couplings comprises a metal coupling nut which has a plurality of radially spaced-apart and vertically disposed slits formed therein which extend thereinto to create weakened areas or zones in the coupling nut. The coupling nut is embedded in a fiber-reinforced material which provides the necessary hoop strength to the coupling nut. The base plate of the pole is positioned on the upper ends of the coupling nuts and is secured thereto by bolts extending downwardly through the base plate of the pole. If the pole is struck by a vehicle, the fiber-reinforced body members, as well as the coupling nuts, fracture to permit the pole to break away from the foundation. The fiber-reinforced body member of the coupling not only adds hoop strength to the coupling nut, but prevents the metal coupling nut from being exposed to corrosive elements such as salt or the like.

Abstract: A fastener nut is formed with anti-cross threading features that include a rounded or chamfered edge at the entry end to the nut, followed by an unthreaded cylindrical counterbore that extends axially from the entry end to the threaded section of the bore. The rounded or chamfered entry end prevents cross threading and the unthreaded section is of sufficient length to ensure substantially collinear alignment between the threaded fastener and the correspondingly threaded nut before threaded engagement occurs. An optional radiused portion is formed between the unthreaded and threaded sections of the nut to further prevent cross threading. The nut can be a weld nut formed with weld protrusions which enable the nut to be welded to a large structural member before mating engagement with a threaded fastener occurs. The nut can additionally have convex or concave or other tactile feed back features that induce vibration when a large off-angle is being attempted.

Abstract: A terminal block assembly for electrical generators, such as high speed AC generators used in aircraft, is made from components that are readily assembled and disassembled for ease of installation, maintenance, and repair. The terminal block assembly is formed of a terminal block and one or more terminal assemblies. The terminal block has a main body with at least an upper surface and a lower surface. A first cavity is formed in the main body lower surface, and an opening that extends through the main body between the upper surface and the first cavity. A threaded fastener is inserted into the opening and into the first cavity, and a bolt is coupled to the fastener to secure the fastener in the opening. Each terminal assembly is coupled to the terminal block and includes one or more electrically conductive terminal plates, feed-throughs, and slugs for connection to stator output leads, that are electrically and mechanically coupled together using electrically conductive fasteners.

Abstract: A self locking fastener system is disclosed for light-weight ballistic resistant applications. The fastener system includes a ballistic resistant cap nut with an integral shoulder. The shoulder is formed onto the mating surface of the cap nut and is keyed to lock with a cut-out in a structural member to which the fastener system is secured. In a commercial aircraft, the cap nut is located on the passenger cabin side of the ballistic resistant flight deck door and prevents tampering therewith that might otherwise lead to disassembly or damage to the fastener system and degrade the ballistic resistance of the door assembly. Thus provided, the fastener system is resistant to removal by manipulation of the cap nut as well as damage from ballistic projectiles. The shoulder of the cap nut increases the shear area of the fastener along the plane of the mating surface thereby enhancing the fastener's resistance to shear loading. The cap nut is constructed of titanium or stainless steel.

Abstract: A weld nut has weld projections on both sides. The projections concentrate heat and melt when in contact with a component part, to form a lasting weld of the nut to the component part. Because there are weld projections on both sides of the nut, there is no risk that the nut will be placed against the component part upside down.

Abstract: A screw-and-nut assembly comprising a support secured to the nut, which support is provided with a surface in contact with the thread of the screw, and an electrical sensing member responsive to mechanical interaction with the thread of the screw, the sensing member being placed in the support close to said surface to come into interaction with the thread of the screw in the event of said surface wearing, wherein the support and the nut are constituted by the same block of material, the sensing member thus being placed inside the nut.

Abstract: An object of the present invention is to provide an excellent weld nut wherein the weld nut and an iron plate are closely fixed together by inserting extra metal materials upon welding into a groove around a weld projection. The present invention relates to weld nuts each having such a groove in the vicinity of such a weld projection.

Abstract: Insert nut for a screw nut joint of the type which comprises a substantially rectangular block, of which the short side substantially corresponds to the width of the outer groove portion in a T-formed groove, which outer groove portion is delimited by side flanges in a profile or the like and which inner groove portion is expanded relative to the outer groove portion. The long side of the insert nut substantially corresponds to the width of the inner groove portion, and which nut by rotation can be transversally positioned and be brought into contact with the underside of the side flanges of the groove. The nut is designed with a substantially quadratic shoulder section, which is arranged concentric with the threaded hole of the nut, and with substantially the same width as the short side of the nut.

Abstract: A novel, one-way nut fastener including a nut body with a side wall that is internally threaded and lobes that extend from the side wall of the nut body. Each lobe has a flat portion that extends substantially radially away from the side wall and a curved portion that extends from the flat portion to the flat portion of an adjacent lobe. A special tool uses the leverage that is gained from the flat portions of the lobes to tighten the cap threads onto the threads of a stem portion. Since the leverage gained from the lobes, which is used to tighten the nut fastener, cannot be used to loosen the fastener, it is much more difficult to remove the nut fastener.

Abstract: A nut fastener is formed with anti-cross threading features that include a rounded or chamfered edge at the entry end to the nut, followed by an unthreaded cylindrical counterbore that extends axially from the entry end to the threaded section of the bore. The rounded or chamfered entry end prevents cross threading and the unthreaded section is of sufficient length to ensure substantially collinear alignment between the threaded fastener and the correspondingly threaded nut before threaded engagement occurs. An optional radiused portion is formed between the unthreaded and threaded sections of the nut to further prevent cross threading. In a preferred embodiment, the anti-cross threading nut is a weld nut formed with weld protrusions which enable the nut to be welded to a large structural member before mating engagement with a threaded fastener occurs.

Abstract: A bolt made from shape memory alloy that exists in a first state and is capable of changing to a second state when heated and remains in that second state even when cooled is used to self torque itself and clamp a first fixture to a second fixture. Preferred methods for using the self-torquing bolt are disclosed.

Abstract: A plate nut assembly is provided in which a protrusion provided on a nut has a centering guide function relative to a circular hole so that the protrusion reliably fits in the circular hole to prevent displacement of the nut assembly, even if an external force is applied in a direction perpendicular to an axis of a bolt threaded to the nut. Around an entrance of a threaded hole on one side of the nut, of such a dimension so as to be received within a circular hole formed beforehand in a wall or the like, at a position where the nut is inserted into the hole, the protrusion is formed so that height of the protrusion decreases in a direction away from the threaded hole. A recess having substantially the same outer shape as that of the protrusion is formed around the threaded hole on another side of the nut. The recess has opposed end walls that are inclined such that a distance between the opposed end walls decreases in a direction toward a bottom of the recess.

Abstract: A nut assembly is proposed in which deformation will not occur at the end of a threaded hole formed in the nut and it is not necessary to give special consideration to the formation of female threads. A nut is pivotally and slidably mounted between opposed arms of a frame. A threaded hole is formed in the nut so as to extend therethrough, a ridge is integrally provided on the back side, and a hole is provided coaxially with the threaded hole. The hole has an inner diameter substantially equal to or greater than the root diameter of the female threads of the threaded hole.

Abstract: A pin pulling device moves a member such as a pin or shaft by a non-pyrotechnic actuation force, such as a spring(s). The actuation member or spring(s) is (are) held in the compressed and loaded position by a release mechanism, such as an explosive bolt coupled to the member through a retainer. When activated by a signal, the release mechanism is severed from the retainer and the member is actuated by the force of the actuation member or compressed springs as the springs expand.

Abstract: The present invention provides an anti-tamper nut that has a threaded bore and an angled outer surface. The angled outer surface has a plurality of ribs extending from a first face to a second face of the nut. A wrench adapted to mate with the outer surface of the nut rotationally drives the nut along the threads of a threaded member.

Abstract: A nut includes an extended flange and a center hole. A shoulder is formed onto the edge of the center hole to achieve an easier and faster assembly. The shoulder has an essentially tubular shape and is provided with a thread on its inside wall.

Abstract: An elongated T-nut fastener is formed from a single piece of material. The fastener includes a barrel and a flange, with a threaded portion in the barrel and an unthreaded portion beyond the threaded portion. Fastening sites are provided at spaced locations along the length of the fastener.

Abstract: Apparatus and method for forming a pin and nut fastener assembly for temporarily or permanently securing two panels having conventional drilled generally aligned holes into which the assembly is inserted. Weight of the pin and nut is reduced while retaining predetermined industry established strength requirements. The thread section of the pin is reduced along with the mating thread of the nut. The pin may be cold-worked in critical areas.

Abstract: A deformable wrench for applying torque to a nut engaging a threaded fastener includes a wrench body having a center portion with at least one wing portion extending therefrom. The wrench body is formed from an elastic material and a socket aperture extends through the central portion between spaced upper and lower surfaces thereof. The socket aperture is configured to cooperate with the profile of the nut to permit rotation relative to the fastener by applying force to the wing portion of the wrench. At a predetermined torque value, the walls of the socket aperture deform to permit rotation of the wrench relative to the nut thereby preventing over-torquing the nut on the fastener.

Abstract: A fastening device for securing tubes, pipes and the like is formed of a mounting rail (3) having a C-shaped cross-section and an elongated space (2) and a retaining plate (1). The retaining plate (1) has a tapped through hole running transverse to the elongated space (2), the tapped hole has an internal thread for form-locking reception of a fastening element. Further, the retaining plate (1) has on the side (13) facing inwardly from the elongated space (2), at least one web facilitating rigidity and positioning, in order to provide a manageable and economical fastening device with high load capacities (P).

Abstract: A lock nut comprising a solid nut body having a flange, from which a neck projection extends axially, being provided at its end surface with an annular shroud, from which at least two claws extend radially.

Abstract: A nut fastener is formed with anti-cross threading features that include a rounded or chamfered edge at the entry end to the nut, followed by an unthreaded cylindrical counterbore that extends axially from the entry end to the threaded section of the bore. The rounded or chamfered entry end prevents cross threading and the unthreaded section is of sufficient length to ensure substantially collinear alignment between the threaded fastener and the correspondingly threaded nut before threaded engagement occurs. An optional radiused portion is formed between the unthreaded and threaded sections of the nut to further prevent cross threading. In a preferred embodiment, the anti-cross threading nut is a weld nut formed with weld protrusions which enable the nut to be welded to a large structural member before mating engagement with a threaded fastener occurs.

Abstract: An off-set adjusting nut for use with a bolt permits adjusting at least one characteristic of mechanically connected members. The bolt has a head and a shank extending therefrom, at least a portion of the shank being threaded for engagement with the adjusting nut. The adjusting nut includes a body defining a nut axis therethrough. The body further defines an upper surface and a lower portion. A round flange is formed integral with the body at the lower portion. The flange is formed on the body collinear with the nut axis. An eccentric bore is formed in the body extending from the upper surface to the lower portion and through the flange. The bore has a thread formed therein for engaging the bolt shank thread. The bore is formed off-set in the nut body and defines a bore axis that is parallel to and spaced from the nut axis.

Abstract: A high strength sucker rod coupling for use with high strength sucker rods, and methods for fabricating the coupling. The coupling is fabricated from a hardened, hollow cylindrical coupling blank. An outer surface of the coupling blank is coated with spray metal alloy, and the coated blank is heated to fuse the spray metal to the outer surface thereby forming a wear layer. This coating decrease brittleness of the wear layer, and limits cracking and subsequent stress riser effects on fatigue performance. The coupling blank is austenitized and liquid quenched to a specified hardness range. Fully cold formed threads are formed on an inner surface of the coupling blank. The fully cold formed threads maintain fatigue properties which are superior to fatigue properties obtained with partially cut, partially rolled threads on prior art high strength couplings.

Abstract: A barrel nut for securing furniture panels is comprised of a cylindrical body with an external thread extending between its opposite ends. The cylindrical body is arranged for being positioned in a snug fitting hole in a furniture panel. A transverse hole is positioned completely through the cylindrical body and has an internal thread extending between its opposite ends. The transverse hole is arranged for receiving a bolt extending from an adjacent furniture panel. A tool socket is arranged at an outer end of the cylindrical body for receiving a turning tool which can screw the cylindrical body into the snug fitting hole. An alignment mark aligned with the transverse hole is provided on the outer end of the cylindrical body to indicate the position of the transverse hole for facilitating alignment with the bolt.