Abstract: A polymeric fastener for use in the construction industry for fastening wood and other basic materials together. The polymeric fastener can be formed in the basic shape of a nail and/or a staple-like fastener. Preferred embodiments of the polymeric fastener include a hardened binder embedded with a filler and/or a core for adequate strength as required for use with a delivery device powered by pneumatics, hydraulics, or other mechanical systems.

Abstract: A fastener for connecting two layers of stacked plate-like elements includes first through fifth sections. The first section is configured to abut against an outer side of the first plate-like element. The second section has a height corresponding to a thickness of the first plate-like element and is receivable in a through hole of the first plate-like element. The third section is configured to pass through the through hole of the first plate-like element in a first orientation, and a first side of the third section is configured to abut against an inner side of the first plate-like element in a second orientation, and a second side of the third section is configured to abut against an inner side of the second plate-like element. The fourth section is configured to pass through the through hole of the first plate-like element in the first orientation, and the fourth section is receivable in a through hole of the second plate-like element. The fifth section is configured to hold the second plate-like element.

Abstract: A method of applying a corrosion-resistant coating to a fastener that includes preheating an area of the fastener to be coated to elevate a temperature of the area and spraying the preheated area of the fastener with a molten or semi-molten metal. In one embodiment, a corrosion-resistant coating applicator includes a support structure, a rotatable slotted fastener conveyer supported by the support structure, a feeder configured to feed fasteners to the rotatable slotted fastener conveyer, a fastener aligner configured to make head portions of the fasteners aligned with each other, a heater configured to heat head portions of the fasteners as the fasteners are being conveyed by the slotted fastener conveyer, and a sprayer configured to apply a corrosion-resistant coating to the heated head portions of the fasteners being conveyed by the slotted fastener conveyer. The present disclosure also provides corrosion-resistant coated fasteners made using the coating methods and/or coating apparatus.

Abstract: A fastening arrangement with a screw having a shank with a front end that is to be inserted into a hole drilled into a substrate, and at least one thread, whereby the thread is arranged on the shank, and with a squeezing unit having a compound reservoir containing a compound for filling a gap that exists between the shank and the wall of the drilled hole, with a squeezing disk towards which the front end of the shank can be moved in order to squeeze the compound out of the reservoir, and having a holding element for fastening the squeezing disk in the drilled hole, whereby, arranged on the holding element, on the one hand, there is the squeezing disk and, on the other hand, a stop element that comes to rest against the opening of the drilled hole.

Abstract: The jigsaw puzzle includes a baseplate used with attachable puzzle pieces. The baseplate has multiple upward-facing engagement mechanisms that are engaged with corresponding and complementary puzzle piece rear-facing engagement mechanisms. The rear-facing engagement mechanisms and the complementary puzzle piece rear-facing engagement mechanisms are designed so as to leave a space between the bottom of the puzzle piece and the top surface of the baseplate to facilitate removal of the puzzle pieces. An optional pry tool can be inserted in to the space to easily remove the puzzle pieces after play, storage, or display. An optional hanger/joiner can be utilized to hang the completed puzzle vertically and/or to join two baseplates to create increased play opportunities.

Abstract: An improved roofing system including a batten assembly comprising support battens and clips. The clips are made of metal wire having one portion shaped to retain roof outer coverings and a further portion shaped to secure the clip to the batten by spring torsion force of part of the clip acting against the batten.

Abstract: A method for a structure having a countersunk fastener head includes forcing an aliphatic urethane surfacer into a void around the fastener head.

Abstract: A nail having an offset head is configured with a multi-step support gusset formed integrally between an undersurface of the offset head and a superior portion of a shank. The head of the nail is relatively thin, and the shank is positioned radially off center of the head. A first portion of the gusset defines an angle relative to the shank axis and the second portion of the gusset defines an angle relative to the shank axis different from that of the first portion. The support gusset reinforces the junction of the shank with the head, supports the toe of the head, and distributes the force of a load on the head through a longitudinal axis of the shank, preventing the toe from bending or yielding and prevents the shank from yielding to the stresses of the load applied.

Abstract: Disclosed is a securing article combination including a pin with an oversized head (top) and a cap to fit snugly over the pin point (tip) after the pin has been used to join multiple layers of a material or multiple materials. The materials may be of cloth or fabric natures, as well as other items for which the securing device may be suitable for use. Alternatively, the pin head may be of a variety of decorative shapes to provide a decorative use in addition to its securing function. Such use is made possible due to the convenient use of a cap of a shape that conforms to the shape of the pin shaft and made of an elastomeric material, typically clear or opaque.

Abstract: A generally U-shaped surgical staple comprises a base 10 and a pair of generally “L”-shaped legs 12 extending substantially perpendicularly from opposite ends of the base respectively. The legs 12 in use of the staple are bent through approximately 90° relative to the base. To effect a greater compression of the stapled tissue the legs include a penetrative portion 16 adjacent the tip and a compressive structure 30 which, due to its increased height relative to that of the penetrative portion, spreads the compressive forces of the staple further along the length of the incision being closed. The compressive portion also provides a depth stop to avoid the tip penetrating too deeply into the tissue in which it is deployed.

Abstract: A photoluminescent oxygen probe including a tack with a layer of a pressure-sensitive adhesive and an oxygen-sensitive photoluminescent element on the underside of the head. The probe is effective for sensing oxygen concentration within an enclosed space by puncturing the container defining the enclosed space the with the probe's shank and adhering the underside of the probe's head to the container so as to sealingly surround the puncture, thereby placing the oxygen-sensitive photoluminescent dye on the underside of the probe's head into sensible communication with the enclosed space through the puncture hole.

Abstract: Embodiments relates to a fastener having a head portion and an interlock portion comprising a bulk solidifying amorphous alloy comprising a metal alloy. The fastener could further have a screw portion. Other embodiments relate to methods of making and using the fasteners.

Abstract: An anti-tamper system including: a fixing device and an anti-tamper detection device; the fixing device comprising a body and a head whereby the head having a larger cross section then the body for enabling a tool to engage and drive the body into a first material layer thereby makes a firm connection with the anti-tamper detection device between the head and the first material layer; the fixing device further comprising a lock wherein the head is locked to the body by the lock where there is no external magnetic field and wherein the head becomes disengaged from the body when the lock is unlocked by an external magnetic field; and whereby the anti-tamper detection device detects and records a change the connection when the head becomes disengaged.

Abstract: In accordance with at least one exemplary embodiment, a pushpin retaining device is disclosed. An exemplary pushpin retaining device can include a resilient, elongated pin that can have a first end portion for puncturing and a second end portion. A grip foot can be operatively associated with the second end portion of the pin. Alternatively, a cut edge can be on the second end portion of the pin. A method of retaining objects without object puncture can include providing a pushpin retaining device. The method can also include puncturing a support surface with an end of the pin of the pushpin device and pressing a portion of an object against the support surface with the grip foot or cut edge, respectively.

Abstract: In accordance with at least one exemplary embodiment, a pushpin retaining device is disclosed. An exemplary pushpin retaining device can include a resilient, elongated pin that can have a first end portion for puncturing and a second end portion. A grip foot can be operatively associated with the second end portion of the pin. Alternatively, a cut edge can be on the second end portion of the pin. A method of retaining objects without object puncture can include providing a pushpin retaining device. The method can also include puncturing a support surface with an end of the pin of the pushpin device and pressing a portion of an object against the support surface with the grip foot or cut edge, respectively.

Abstract: A fastener and a method for reducing wear on a driver blade in a fastening tool includes applying a layer of solid-based lubricant between the head of a fastener and a driver blade end. The fastener is for use in a fastening tool and includes a head, a shank, and a layer of lubricant on the head of the fastener. The lubricant is graphite, molybdenum disulfide, tungsten disulfide, boron nitride, polytetrafluoroethylene (PTFE), nano-diamonds, calcium stearate, sodium stearate, oils, greases, waxes, thermoplastic polymers, or another lubricant that exhibits similar characteristics. Aromatic polyamides (such as Kevlar™), ultra-high molecular weight polyethylene, powdered glass, glass fibers, thermoplastic polymers, and thermoset polymers also are contemplate to provide a barrier to contact between the driver blade and fastener head. The lubricant is sprayed, rolled, brushed, blotted or otherwise applied between the head of the fastener and the driver blade end prior to firing the fastening tool.

Abstract: A fastener having a clamp head which has a clamp with a clamp angle in a range of from 75 degrees to greater than 30 degrees. A nail having a clamp head which has a clamp with a clamp angle in a range of from 75 degrees to greater than 25 degrees. A nail stick having a collation angle which has a value greater than 25 degrees. A method of manufacturing a nail stick having a step of punching a collated band of wires to create clamp heads having clamps which respectively have a clamp angles in a range of from 60 degrees to 40 degrees.

Abstract: A fastener assembly is configured for use in an associated fastener driving tool for driving a fastener from the assembly into an associated substrate. The assembly includes a row of fasteners, each having a shank, arranged substantially parallel to each other. A collation system is formed from a plastic material that is molded onto and adhered to the fasteners. The plastic material is molded to define a collar portion substantially encircling the fastener shank and a connecting portion extending between and connecting adjacent collar potions. The plastic material is formulated from an adhesive polymer. When the fastener is driven from the driving tool, the collar portion remains adhered to the fastener such that the collar portion penetrates the substrate with the fastener.

Abstract: In accordance with at least one exemplary embodiment, a pushpin retaining device is disclosed. An exemplary pushpin retaining device can include a resilient, elongated pin that can have a first end portion for puncturing and a second end portion. A grip foot can be operatively associated with the second end portion of the pin. Alternatively, a cut edge can be on the second end portion of the pin. A method of retaining objects without object puncture can include providing a pushpin retaining device. The method can also include puncturing a support surface with an end of the pin of the pushpin device and pressing a portion of an object against the support surface with the grip foot or cut edge, respectively.

Abstract: A fastener assembly is for use in an associated fastener driving tool. The assembly includes a row of fasteners arranged substantially parallel to each other. Each fastener has a shank and defines an axis. A collation system is formed from a plastic material that is molded onto and adhered to the fasteners. The plastic material defines a collar portion at least substantially encircling the fastener shank and a connecting portion extending between and connecting adjacent collar portions. The connecting portion includes a bridge and a rib. The bridge is a relatively thin, elongate element spanning adjacent collar portions and the rib is a relatively thick, short element that is disposed at about an upper portion of the bridge. When the fastener is driven from the driving tool, the collar portion remains adhered to the fastener such that the collar portion penetrates the substrate with the fastener. The connecting portion can include a weakened region for separating the connecting portion from the collar.

Abstract: In accordance with at least one exemplary embodiment, a pushpin retaining device is disclosed. An exemplary pushpin retaining device can include a resilient, elongated pin that can have a first end portion for puncturing and a second end portion. A grip foot can be operatively associated with the second end portion of the pin. Alternatively, a cut edge can be on the second end portion of the pin. A method of retaining objects without object puncture can include providing a pushpin retaining device. The method can also include puncturing a support surface with an end of the pin of the pushpin device and pressing a portion of an object against the support surface with the grip foot or cut edge, respectively.

Abstract: A fastener assembly for use in an associated fastener driving tool for driving a fastener from the assembly, in sequential order, into an associated substrate, includes a row of fasteners arranged substantially parallel to each other, each fastener having a shank and defining an axis and a collation system formed from a plastic material that is molded onto and adhered to the fasteners. The plastic material defines a collar portion at least substantially encircling the fastener shank and a connecting portion extending between and connecting adjacent collar portions. When the fastener is driven from the driving tool, the collar portion remains adhered to the fastener such that the collar portion penetrates the substrate with the fastener, and the connecting portion includes a preferentially weakened region to influence separation of the connecting portion from the collar at a desired location.

Abstract: A fastener for being inserted a first depth d1 through a first object and a second depth d2 into or through a second object, is provided. The fastener includes, but is not limited to, a head having an outer surface opposed to an inner surface, a shank connected with the inner surface of the head at a first end and forming a tip at a second end opposed to the first end, and an identification marking formed on the outer surface. The outer surface remains exposed upon the fastener being inserted into an object. The shank has an actual length La from the first end to the second end, and wherein the actual length La is equal to or greater than the sum of the first depth d1 and the second depth d2. The identification marking indicates an embedment depth de of the fastener.

Abstract: The Butterfly Push-Pull Pin, also referred to as a force advantageous push-pull pin in this application is a practical fastener used to support penetrable materials on supporting material such as a bulletin board, notice board, tack board, wall or other element penetrable by a push pin. In the Butterfly Push-Pull Pin, two broad, sloped, opposing sides of a polygonal handle are grasped to push the pin in. Two other broad, sloped, opposing sides of the polygonal handle are used to pull the pin out.

Abstract: A part clamp is temporarily held in a short cylindrical portion provided on a contact arm of a nailing machine and is nailed to a building body or the like by the nailing machine. The part clamp is provided with a base portion having a through hole at its center for inserting a nail therethrough, and an engaging portions for engaging with the short cylindrical portion. When the part clamp is pushed in the axial direction of an injection port of the nailing machine, the part clamp is temporarily held in the short cylindrical portion. The load to push the part clamp to engage with the short cylindrical portion is lower than the load to push the contact arm to slide along the injection port.

Abstract: A kit of components for use with a pin permeable board, the kit of components comprising a pin suitable for penetrating the pin permeable board for frictional engagement with the pin permeable board; and a magnet; further wherein the pin has a gripping handle, the gripping handle having a magnet attractive top surface configured to receive the magnet; whereby the magnet can be attached to the gripping handle by magnetic force thereby to allow an object to be displayed to be secured to the gripping handle between the handle and the magnet, and wherein the magnet remains in position on the gripping handle by magnetic attraction through the object when the pin is engaged in a vertically disposed pin permeableboard.

Abstract: A fastener for driving into a substrate has a head having an upper surface and a lower surface, a penetrating tip and a shank extending from the lower surface of the head to the penetrating tip. At least one deformable feature is formed on the head. The deformable feature is configured to absorb energy and to deform. When a driving element is driven onto the head to drive the fastener into the substrate, the deformable feature absorbs energy and is deformed as the head contacts the substrate.

Abstract: A planar sheet mounting device comprising: a frame unit; at least one retaining unit connected to the frame unit, wherein the at least one retaining device comprises: a first plurality of formed segment pairs, wherein a formed segment pair comprises a first formed segment disposed on a second formed segment, wherein the second formed segment is substantially identical to the first formed segment, wherein the first formed segment is oriented in a plane substantially parallel to the plane of the second formed segment, whereby a planar sheet is retained when interposed between the first formed segment the second formed segment; a holder, wherein the first plurality of formed segment pairs are coupled to holder at least one point on each formed segment pair of the first plurality of formed segment pairs, and wherein the first plurality of formed segment pairs are oriented adjacent to each other; an affixant coupled to the holder for removably affixing the first plurality of formed segment pairs and the frame unit

Abstract: A coated fastener has a tip and a coating on the fastener, at least at the tip. The coating is formulated from a solvent-borne resin. The fastener includes one or both of a solids based additive in the solvent-borne acrylic resin and an overcoat on the solvent-borne acrylic resin. A strip of collated fasteners with the coating is also disclosed.

Abstract: A full-round head nail having an offset head is configured with a gusset formed integrally between an undersurface of the offset head and a superior portion of a shank. The head of the nail is relatively thin, and the shank is positioned radially off center of the round head such that no heel is formed at a point tangential to both the head and the shank. The gusset has a lofted surface tapering radially from a roundness at the zero heel to a taper at the toe. The gusset reinforces the junction of the shank with the head, supports the toe of the head, and distributes the force of a load on the head through a longitudinal axis of the shank, preventing the toe from bending or yielding and prevents the shank from yielding to the stresses of the load applied.

Abstract: A self-sealing attachment assembly, includes a base portion defining a receptacle having an opening at one end and a surface with a through-hole at an opposite end, a sealant material in the receptacle, and a cover secured to the base portion and enclosing the opening, wherein the cover is configured to receive a driving force from a fastener and dispenses the sealant material via the through-hole by displacement through the receptacle when actuated by the driving force. A method is disclosed for installing a building material to a framing that includes mounting a self-sealing attachment assembly onto a fastening member and driving the fastening member through the sealing assembly and the building material toward the framing to dispense a sealant material to seal the penetration hole formed by the fastening member in the building material to form a watertight seal.

Abstract: A nail is used to fasten wood, plastic, shingles, siding and composite items together. A nail has a head and a shank or shaft. A nail is typically made of a steel or metal alloy but could be made of other materials. The nail is different from conventional nails in that its shank or shaft is not straight or twisted. The shank is tapered. The end near the head of the nail is smaller in diameter then the end that penetrates the material (the point). The shank tapers from the point progressively until it reaches a section near the head that expands to the same diameter as the shank near the point. The shank then tapers again until it reaches the head. The amount of taper varies with the different applications of the nail. The nail's shank also has rounded rings toward the head end of the shank. The rings provide the nail with stability against the host material until the host material rebounds against the tapered shank.

Abstract: This patent application describes a kind of disc to be used when driving in a nail, the use of which makes it easier to extract the nail afterward. This disc comes in various shapes, a few of which use a specially shaped nail that is also described in this patent application.

Abstract: A pushpin device of one embodiment preferably comprises a head adapted to allow a user to apply pressure to the head without discomfort. A longitudinally extending fastening member comprises a point at a distal end and is coupled to the head at a proximal end. A base comprises an aperture. The aperture is configured to allow the fastening member to pass through the base as the head moves proximate to the base. An outer member is coupled to the head and the base. The outer member comprises a first position in which the head is spaced from the base and the outer member encloses a longitudinal segment of the fastening member. In a second position the head is proximate to the base and the outer member is deformed, thereby allowing the fastening member to extend through the aperture. The outer member exerts a countering force on the base and the head. One of the head and the base comprises magnetically susceptible material and the other comprises magnetic material.

Abstract: A vehicle interior component in which a back-fastened member such as an upholstery or a noise insulator is fastened to a back side of a resin interior base material with a fastener, includes: a fastener-driven rib having plasticity and plate-like shape being integrally formed on the back side of the resin interior base material so as to protrude from the back side in such a posture that the fastener-driven rib is inclined at a predetermined angle with respect to the back side; and the fastener being driven into the fastener-driven rib so as to pass through the fastener-driven rib in such a posture that the fastener intersects with the fastener-driven rib, whereby the fastener is engaged with the fastener-driven rib.

Abstract: A head is formed so that the maximum diameter portion as viewed from the front is arranged in a different position axially with respect to the maximum diameter portion as viewed from the side. The horizontal cross-section of the head is such that a first ellipse is formed in the maximum diameter portion, and a second ellipse is formed in the maximum diameter portion with the long axis perpendicular to the long axis of the first ellipse. The horizontal cross-sectional shape of the head is gradually changed in the axial direction so as to continue from the first ellipse to the second ellipse. Each one of the horizontal cross-sections has the same circumferential length at different axial positions on the head.

Abstract: A fastener is configured for securing a lath to a surface for, for example, the application of stucco to the surface. The fastener includes a fastener having a head, a shank and a penetrating tip. The head has a diameter and the shank has a diameter less than the head diameter. The stucco fastener has a sealing/spacer assembly having spacer element and a sealing element. The spacer element is formed from a relatively incompressible material and has a diameter greater than the shank diameter. The spacer element has a bore therein having a diameter about equal to the shank diameter. The sealing element is formed from a resilient, water-resistant material and is positioned adjacent to and in contact with the spacer element. When the fastener is driven into the surface, the fastener penetrates the surface to secure the fastener to the surface and a portion of the lath is captured between the head of the fastener and the spacer element to space the lath from the surface.

Abstract: A fastener and a method for reducing wear on a driver blade in a fastening tool includes applying a layer of solid-based lubricant between the head of a fastener and a driver blade end. The fastener is for use in a fastening tool and includes a head, a shank, and a layer of lubricant on the head of the fastener. The lubricant is graphite, molybdenum disulfide, tungsten disulfide, boron nitride, polytetrafluoroethylene (PTFE), nano-diamonds, calcium stearate, sodium stearate, oils, greases, waxes, thermoplastic polymers, or another lubricant that exhibits similar characteristics. Aromatic polyamides (such as Kevlar™), ultra-high molecular weight polyethylene, powdered glass, glass fibers, thermoplastic polymers, and thermoset polymers also are contemplate to provide a barrier to contact between the driver blade and fastener head. The lubricant is sprayed, rolled, brushed, blotted or otherwise applied between the head of the fastener and the driver blade end prior to firing the fastening tool.

Abstract: A two-way fastener includes a first member configured to be attached to a first workpiece via a tool selected from the group consisting of: a pair of pliers, a screwdriver, a nutdriver and a hammer; and a second member configured to be attached to a second workpiece such that the second workpiece comes together with the first workpiece and at least substantially hides the entire two-way fastener, the second member extending in an opposite direction as the first member.

Abstract: An attachment means, in particular a nail for use in dry construction, which is made in one piece from a plane raw material by punching and/or cutting and bending, having a shaft on one end region of which a point and on the other end region of which a head bent substantially perpendicularly to the two-dimensional extension of the shaft are formed, wherein sections of the head project over the shaft to both sides of a bend line formed upon bending the head.

Abstract: The present invention pertains to an assemblage of sealing nail essentially containing a nail, a propeller, and a blocker that is partially extended beyond the propeller. Wherein, the nail would sequentially penetrate the propeller, the blocker, and then a plank. By means of the nail entering the plank, the propeller and the blocker would be simultaneously urged to densely cover up where the nail inserted. Therefore, a preferred sealing efficiency between the nail and the plank is achieved to guarantee a favorable grouting on the plank.

Abstract: A fastener for driving into a substrate has a head having an upper surface and a lower surface, a penetrating tip and a shank extending from the lower surface of the head to the penetrating tip. At least one deformable feature is formed on the head. The deformable feature is configured to absorb energy and to deform. When a driving element is driven onto the head to drive the fastener into the substrate, the deformable feature absorbs energy and is deformed as the head contacts the substrate.

Abstract: A nail having an offset head is configured with a multi-step support gusset formed integrally between an undersurface of the offset head and a superior portion of a shank. The head of the nail is relatively thin, and the shank is positioned radially off center of the head. A first portion of the gusset defines an angle relative to the shank axis and the second portion of the gusset defines an angle relative to the shank axis different from that of the first portion. The support gusset reinforces the junction of the shank with the head, supports the toe of the head, and distributes the force of a load on the head through a longitudinal axis of the shank, preventing the toe from bending or yielding and prevents the shank from yielding to the stresses of the load applied.

Abstract: A self-sealing furring assembly includes a spacer and a sealing member abutting the spacer. In another aspect of the disclosure, a self-sealing furring assembly configured to be installed between plaster lath and a frame for a structure, includes building paper mounted on framing for the structure, a sealing member, and a fastening member supporting the sealing member, wherein the fastening member includes a head a and a shank and extends through the plaster lath, the sealing member, and the building paper into the framing so that the plaster lath is between the head of the fastening member and the sealing member, the sealing member being compressed to seal the hole formed by the shank of the fastening member in the building paper. A method for installing an exterior building material to a framing is disclosed.

Abstract: A picture hanger has a base portion having a hole for an elongated fastener (nail or screw). The base portion carries a member enclosing a front face or the entire base portion. The member has a through hole aligned with and on one or both sides of the fastener hole. The elongated fastener is held in place in the holes so that the fastener need not be manually held during driving thereof into a picture frame or wall. The member is injection molded on the base portion, and consists essentially of nylon-6,6 having a Shore A hardness in the range of 80-90.

Abstract: A method of categorizing fasteners and construction connectors by size and type using a color coding system. Each fastener receives a designated and distinct color contained on the surface that is exposed before and after installation. The colors are preselected to define one or more physical properties of the fasteners. A color key is provided to determine the physical properties of the fasteners based on the coloring of exposed portions of the inserted fasteners. Similarly, construction connectors receive a designated and distinct color contained on the surface that is exposed before and after installation. The color represented on the surface of the construction connector is such that the corresponding fastener is the same color.

Abstract: A drawing pin comprises a head portion and a spike, the head portion having an aperture therein in order to receive the spike of a subsequent drawing pin.

Abstract: A fastener that includes a head portion and a body and is configured to be driven into material. The body is configured for engaging the material and the head portion is constructed to be engaged by a driver of a power nailer.

Abstract: A nail comprises a plurality of umbrella-shaped threads spirally formed on the shank and extended from the nail end to the head, wherein the umbrella-shaped thread includes a top face and an end edge face, in which the outer diameter of the top face is greater than the outer diameter of the end edge face, such that the nail can be nailed into a planking easily and successfully without the obstacle of the umbrella-shaped threads. While pulling out the nail, an actuating tool is used directly to rotate back the nail, so as to prevent from damaging the surface of the planking and efficiently save the time and labor.

Abstract: A fixing element of plastic includes a foot part for insertion into an oblong hole of a carrier plate. The foot part includes a head and a shaft. The fixing element can be locked in the oblong hole after the insertion of the head by a quarter turn. The shaft includes a middle strut connected to the head. A shank is formed on each of the two edges of the middle strut at right angles and in opposite directions. A countershank is formed on each of the edges of the middle strut in opposite directions. The shank is elastically bent towards the middle strut during the screwing in of the shaft through the edge of the hole and after a quarter turn returns to its original position. Pressing ramps are formed on two outer ends of the head to prevent a rotation in the opposite direction.