Abstract: The spacer screw has a thread section which can be inserted into a base member, a head section which can be introduced into a structural member and has a thread, and a shank section arranged in between. According to the invention, the thread is provided with a series of slits which in turn is formed from recesses running transversely to the screw axis and interrupting the thread turn at constant distances. When the screw is used, the thread is screwed into the structural member, which, in contrast to the use of known screws, is effected without excessive force. In addition, this screwing-in process takes place independently of the screwing of the thread section into the base member. When the thread section is screwed into the base member and when the head section is screwed into the structural member, the slit-like recesses do in fact generate a draw-in resistance, the draw-through force of the thread of the head section being reduced by the magnitude of said draw-in resistance.

Abstract: To form a welded joint between a fastening means (1) and a structure (2), a fastening means (1) with a holder (3) and a connecting element (4) is proposed. The holder (3) essentially consists of an electrically insulating material. The connecting element (4) consists of a substantially electrically conductive material. The holder (3) substantially surrounds the connecting element (4). The connecting element (4) has a contact face (5) located inside the holder (3). The holder (3) has a through-orifice (6) at least partially overlapping the contact face (5). A contact piece (7) of an electrically operated welding device is introduced through the through-orifice (6).

Abstract: The present invention relates to a blade retention apparatus for a bladed rotor in a turbine section of a gas turbine engine which comprises a rivet grip which has serration at one end and an upset head at the other end, and a sleeve made of a soft metal which is compressed to the serration actually against the surfaces of the disk and the blade. The retention apparatus of the present invention provides a reliable attachment and only requires a simple hand-held pneumatic riveting tool to install.

Abstract: A screw, particularly a wood screw present a combination of a threaded cylindric stem (10) merging, over an inversely frustoconical part (16) with an enlarged diameter cylindric portion (20) which is integral with an underside of a large diameter washer section (23) which, in turn is integral with a shallowly convex head portion (25). The invention is intended for wood screws usually in the range of about 6 mm and provides a reduced chance of injury by providing a smooth merging with the flat surface on which the screw head is located. Also, the screw has an improved torque characteristics making it suitable for use with power screw driving tools.

Abstract: A self-tapping screw consists of a head and a threaded shank which is provided with a blade, a first threaded portion contiguous to the blade, and a second threaded portion contiguous to the head and greater in length, tooth pitch and tooth depth than the first threaded portion. The self-tapping screw is fastened onto a corrugated board such that the blade and the first threaded portion are securely embedded in a girder, and that the second threaded portion is securely embedded in an insulation layer located between the corrugated board and the girder.

Abstract: A pilot screw has a head, a shank beneath the head, a tapered tip at the end of the shank, and a spiral thread surrounding the shank. A large number of spaced auxiliary threads are disposed on the tapered portion of the head. A large number of spaced secondary threads are disposed on the shank between the pitches, and plural cutting gaps are formed at the end area of the spiral thread.

Abstract: The drywall screw includes an elongated shaft about an axis, a screw head at one end and threads about the shaft. The screw head has a recess having upper and lower portions. The upper portion is comprised of an upwardly flared thin-walled section having convex and concave interior and exterior surfaces, respectively. The lower portion includes a Phillips head slot for receiving a Phillips head driver. The recess in the head of the drywall screw and the outwardly flared head enables the screw to be driven into the drywall without tearing or loosening the paper overlying the drywall, while simultaneously providing a sufficient recess for receiving the drywall mud finishing compound.

Abstract: The bucket elevator construction bolt comprises a flat head and a threaded shaft, the bolt further incorporating a collar adjacent the head, the collar including a plurality of elongate, radially arrayed spline teeth which engage within the material of the elevator belt, maintaining the bolt position against radial torque or vibratory forces applied thereto.

Abstract: A fastener assembly connects two layers of different hardness in a panel. e assembly has a screw and has a mechanism for boring through the softer layer comprised of a collar of material softer than the material of the screw. The screw is tapped into the collar and has a bit for boring through the harder layer of the panel. The screw's head fits into the collar so that the screw and collar can be countersunk together into the softer layer of the panel. The collar has a lead end having a leading cutting edge for drilling into the softer layer of the panel. The collar also has a trailing end having a frustoconical skirt on which is located a trailing cutting edge. The torque to rotate the screw in the collar is greater than a torque to rotate the collar in the softer layer of the panel. But the torque to rotate the screw in the collar is less than the torque to rotate the screw in the harder layer of the panel.

Abstract: A self starting finishing screw with a cylindrical shaft with a taper on one end and a tool engaging recess on the other end. The shaft is threaded along the entire length.

Abstract: In a fastener having a head, which may have having torque-absorbing ribs, and a shank, which is unitary with the head and which has a primary thread formation and a secondary thread formation. The primary thread formation, which defines axially spaced threads along a generally cylindrical portion of the shank and along a tapered tip of the shank, has a generally uniform radial dimension along the generally cylindrical portion of the shank. The secondary thread formation, which defines axially spaced threads between some of the threads defined by the primary thread formation, originates at a region spaced axially from the distal end of the generally cylindrical portion of the shank, terminates at the head, and tapers outwardly from the region where it originates toward the head. The secondary thread formation at the region adjoining the head has a radial dimension less than the generally uniform radial dimension of the primary thread formation along the generally cylindrical portion of the shank.

Abstract: The present invention provides a roofing fastener, a roofing assembly including the roofing fastener, and a method of installing the roofing fastener into the roofing assembly. The roofing fastener includes a head and a shank integrally connected thereto. The shank and the thread thereon permits the roofing fastener to be self-tapping and threaded into a base substrate such as a concrete deck. Preferably, the roofing fastener includes a polygonal socket within nubbins thereon to squeeze about a drill bit. Also, ideally the head of the roofing fastener is round and has a diameter which is greater than the length of the shank. Ideally, the fastener is made of a low-moisture material which can absorb water from the surrounding substrate causing the fastener to swell and increase its holding power.

Abstract: The invention relates to a countersunk head screw with an even number of ribs with countersinking blades on the underside of the screw head and projecting therefrom. Every other rib has a step at its end towards the screw shaft formed by shortening the rib concerned in relation to each adjacent rib.

Abstract: A combination screw and clearance drill is provided that in one mode of operation is able to drill a pilot hole for the screw threads through a top piece of material and then screw into a lower piece of material, thus enabling the two pieces of material to be screwed tightly together in a single operation. The screw is designed in such a manner that the ability of the screw to drill a clearance hole for the threads does not substantially effect the gripping ability of the screw. In one direction of rotation the screw is able to drill the clearance hole for the threads of the screw and by reversing rotation the screw is able to stop drilling a clearance hole and function as a regular screw. Flutes in the screw head cut a counter bore for the head when the head contacts the surface of the top piece of material.

Abstract: The present invention provides a method of reinforcing a concrete made construction having the step of fixedly securing a grating member acting as a reinforcement onto a surface of a concrete made construction with a fixture so that the fixture imparts tension force to the grating member in a plane of the grating member. The fixture comprises, for instance, an anchor and a pin. The anchor includes an insertion portion to be inserted into a concrete made construction, the insertion portion being formed at a distal end thereof with an expanding slot, an arc-shaped head portion, and a tapered portion connecting the insertion portion to the head portion and having a cross-sectional area increasing from insertion portion towards the head portion, a through hole being formed axially through the anchor. The pin is to be inserted into a concrete made construction through the through hole.

Abstract: A novel, self-sealing a headlamp adjustor mechanism is used to effect pivotal movement of a movable headlamp component in a headlamp arrangement. The headlamp adjustor mechanism includes a bushing having an initially unthreaded bore therethrough and an adjusting screw member having a shank. The shank of the adjusting screw member has a threaded portion and an unthreaded portion. When the adjusting screw member is rotated through the bore, female threads are cold-formed within the bore as the threaded portion contacts the bore and the cold-formed, female threads are deformed and collapsed against the unthreaded portion to seal the bushing against the unthreaded portion as the unthreaded portion contacts the cold-formed threads in the bore.

Abstract: A number of embodiments of wheel locks for vehicle wheels having an opening are disclosed. In each embodiment, the lock includes a plurality of pivotally connected elongated members having end members that are provided with a locking means for locking them together. As a result, the lock can be inserted through the wheel and around a fixed object and locked like a chain. Various embodiments are disclosed for protecting the pivot pins of the pivotal connections from attack and for restraining the pivotal movement of the elongated members. In some embodiments, the pivotal movement is restrained by placing a frictional drag on the components so that the elements cannot freely pivot. In other embodiments the degree of pivotal movement in one direction is limited more than in another direction so that the lock can only be installed in the correct relationship.

Abstract: A self-countersinking screw including an inverted-conical head portion formed at a top with a cavity adapted to receive a tip of a screwdriver and having a conical bottom, said conical bottom having a plurality of triangular recesses each having a lateral side extending inwardly to form a sharp edge and a space for receiving chips, a threaded portion, and a tapered portion having a large diameter connected with the head portion and a small diameter connected with the threaded portion, whereby the sharp edge will make a countersink on a workpiece when the countersunk head screw is turned therein.

Abstract: An exhaust pipe hanger assembly is provided in a vehicle having a rigid structural member. The exhaust pipe hanger assembly includes a continuously linearly extending rigid rod bracket. The rod bracket has a first portion extending through and securely captured within the rigid structural member and a second portion linearly extending from the first portion and extending outwardly from the structural member. The exhaust pipe is suspended from the second portion of the rigid rod bracket. The rigid rod bracket has sufficiently high stiffness and resonant vibrational frequencies such that transmission of exhaust pipe vibration into the vehicle is reduced.

Abstract: A force fit connecting element (1), particularly a wheel stud, which may be force fit into in a drilled hole (3) through the exertion of an axial force, having a shank (5) and a stop (4) in the shape of a head, a collar or the like, having a diameter larger than shank (5). The shank (5) has on the side facing the stop (4) a force fit section (10), which is oversized with respect to the corresponding drilled hole (3). The shank (5) has on the side facing away from the stop (4) a section (22) with a fastening thread (23). The force fit section (10) has a multiple-threaded, preferably at least triple-threaded, helical profile (11). The helical profile (11), with respect to the cylindrical surface area of the drilled hole (3), has a contact area fraction (33) of at least 30% and is made by cold forming.

Abstract: A self-drilling anchor installable in a wall by means of a screwdriver, the anchor being adapted to receive a threaded fastener serving to hold a fixture against the wall. The anchor includes an externally-threaded shank section having a head engageable by the screwdriver and a longitudinal bore threadably to receive the fastener. Integral with the shank section and extending axially therefrom is a drill section having at least one cutting member and guide means therefor, whereby as the anchor is turned in to the wall by a screwdriver, the cutting member then bores a round hole therein whose bank is engaged by the guide means to ensure circularity of the hole. And as the anchor continues to turn, the shank section enters and taps the hole until its head engages the outer surface of the wall to complete the anchor installation.

Abstract: A screw for use with a washer as a sealing fastener having formations near the head of the screw to increase driving resistance when the portion having the formations reaches a surface into which the screw is being drilled. The screw includes a shank with a tip end and a head end. A head at the head end may be driven by a driving tool such as a pneumatic or electric drill. To facilitate retention of the washer the head has a flange that forms a recess. The shank has an enlarged portion near the head adjacent to the recess and the enlarged portion has ridges. The enlarged portion, including the ridges, increases the driving resistance of the screw. This increase in resistance gives notice to an operator of the driving tool that an appropriate driving depth and torque have been achieved. Preferably, the washer has an inner diameter surface with fully radiused projections.

Abstract: A combination of a base attachment structure and a cutting tool, where the base attachment structure includes a connection bolt (8) inserted and movably fitted in an aperture (9a) formed in a curved plate (9) of a gear housing (2) and a cross-shaped slide aperture (11) formed in an arch-shaped projection member (10) extending from a base (7). The connection bolt (8) includes a first upper threaded portion (8a) having threads running in a first direction to form a left-handed screw, and a second lower threaded portion (8b) having threads running in a second direction, opposite to the first direction, to form a right-handed screw. The first threaded portion (8a) is fitted into a hole (12a) formed in a pressure plate (12), whereas the second threaded portion (8b) pierces into an aperture (13a) formed in an arch-shaped clamp plate (13) and is then screwed to a right-handed fixation nut (16).

Abstract: A bone plate for stabilizing the anterior column of the spine has a lower curved surface and an upper surface having two intersecting planes in each of which is a screw hole, the axes of the holes being skewed relative to one another. A bone screw used to secure the plate, has a single start buttress thread near the tip and a two start machine thread near the head, the threads being continuous and of constant pitch.

Abstract: A plurality of screws are held in a screw cartridge that is housed within a magazine, and in a first embodiment a spring urges the screws toward a screw injector chamber where they are driven into a substrate upon activation of a motor-operated screw gun. In the first embodiment, the screw cartridge is a blister pack that is split open by a bar positioned at the leading end of the cartridge. The magazine is positioned normal to a drill guide housing that includes a drill bit housing, a screw injector housing, and a screw discharge housing, and the leading end of the magazine is in open communication with the screw injector housing. The trailing end of the magazine is closed by a snap on end cap, and a spring is positioned between the end cap and a trailing end of the screw cartridge to urge the screws into the screw injector housing. Brackets are used to secure the attachment to the screw gun.

Abstract: A fastening screw is provided with a locking function to prevent loosening thereof after being tightened.

Abstract: A fence system including a frame and a plurality of foraminous panels attached to the frame. The foraminous panels are constructed with continuous integral strands forming a zig-zag pattern defining cell apertures therebetween which are connected by integral bonds extending between each of the strands. The cell apertures define a non-circular interior shape. A fastener of the fence system has a shank, a head attached to one end of the shank, and may include a shoulder positioned between the shank which is shaped to cooperatively engage a cell aperture. The foraminous panels are attached to the frame with a portion of each neighboring panel having an overlapping area through which fasteners are inserted and attached. A reinforcing assembly including at least one reinforcing member attached over each overlapping area and may be attached over other joints or edges to provide added security. An angled top edge cap is attached along a top end of the foraminous panels and is angled to deter climbing.

Abstract: A fastener for insertion through aligned holes of two components to be secured to one another by the fastener. The fastener includes a shaft portion having an end; a fastener head disposed at said end; and a retaining arrangement for maintaining the fastener captive by the components. The retaining arrangement includes a conical collar situated between the shaft portion and the fastener head. Further, the conical collar surrounds the axis and has a maximum diameter base oriented toward the fastener head. The conical collar is provided with radial recesses. The retaining arrangement also has a neck part surrounding the shaft axis and disposed between the fastener head and the conical collar.

Abstract: A one-bolt connecting rod for an internal combustion engine, compressor or other machine; a structure for aligning the shank and cap parts of a two-piece connecting rod; an aluminum fastener for aluminum connecting rods; an extrusion process for making connecting rods; and connecting rod parts made by a fine blanking process. In the one-bolt connecting rod, the unbolted junction of the shank and cap is of the hook-on-lug type, and the bolt runs longitudinally through the junction. The alignment structure is on one side a V-junction with contact only between slanting walls and on the other side a junction of two single-plane walls. The aluminum fastener is a threaded aluminum stud.

Abstract: An improved relief screw is provided for installing a wallboard panel to a stud, which consists of a flat head made of an inverted rectilinear slant height frustrum portion and a straight thin cylindrical portion. The straight thin cylindrical portion is larger than the widest part of the rectilinear slant height frustrum portion, therefore creating an annular flange thereabout. A threaded shank with a conical point extends from a narrow part of the rectilinear slat height frustrum portion, while the flat head bas a recess to accommodate a driving tool element for imparting rotary motion thereto. A structure is in the flat head for relieving particles of the wallboard panel therefrom, after the flat head is driven into the wallboard panel. The top of the straight thin cylindrical portion will be flush with and not damage the outer surface of the wallboard panel, while the annular flange will add more gripping support thereto.

Abstract: A low torque fastener screw for securing a wooden workpiece to a substrate includes an elongated body defining a longitudinal axis and having an enlarged head formed on one end, an external pointed thread formed on an opposite end, an elongated unthreaded shank between the enlarged head and the threaded end, and a reamer formed at the juncture of the shank and thread. The reamer has a plurality of longitudinal cutting edges formed about its periphery which ream out the hole formed by the threaded end to a diameter larger than the shank, thereby reducing frictional resistance to rotation of the screw and optimizing the torque applied by the driving tool.

Abstract: A pin is provided for repairing cracks in a material such as iron casting materials. The pin includes threads with both upper surfaces and lower surfaces which angle upwards toward a head of the pin. A tapping bit is utilized in a hole of similar diameter to the pin, positioned with half of the hole on each side of a crack, the bit creating threads in the hole which are substantially complemental to the threads of the pin. The pin includes a shoulder which has a greater diameter than a diameter of the hole. A neck is located between the head of the pin and the shoulder of the pin having a lesser diameter than any other portion of the pin. When the pin is threaded into the hole, the shoulder abuts against a surface of the cracked material causing the pin to cease translation into the material. Upon further rotation of the pin, the upwardly angled threads draw opposite sides of the crack towards each other.

Abstract: A lock shell comprising a tubular outer shell for receiving lock components, illustratively a spindle, the shell having an annular key way at the front face; the shell has an enlarged head portion at the front and a reduced diameter cylindrical portion extending from the head portion to the rear of the shell; at least one longitudinally extending lug member is disposed on the outer periphery of the cylindrical portion; the at least one lug starts at the enlarged head and extends rearwardly a minor portion of the length of the shell; the lug has portions successively from the enlarged head consisting of straight top and side walls, inwardly tapering top and side walls, and diminishingly angled walls.

Abstract: A self-drilling screw is provided which is suitable for use with both relatively thick metal plate and relatively thin metal sheet. The screw is formed from a blank 1 which includes a shank 2 extending between a head 3 and drilling tip 4. The shank 2, adjacent the head 3, is formed with a frusto-conical enlargement 8. A thread 10, when formed in shank 2, is extended into enlargement 8 so as to create a final part 11 of the thread which, in use of the screw with sheet metal 12, distorts the sheet metal such that it firmly locks onto the enlargement 8. A shallow recess 6 is provided in the underside of head 3 surrounding the frusto-conical enlargement 8.

Abstract: A self-drilling anchor installable in a wall by means of a screwdriver, the anchor being adapted to receive a threaded fastener serving to hold a fixture against the wall. The anchor includes an externally-threaded shank section having a head engageable by the screwdriver and a longitudinal bore threadably to receive the fastener. Integral with the shank section and extending axially therefrom is a drill section having at least one cutting member and guide means therefor, whereby as the anchor is turned in to the wall by a screwdriver, the cutting member then bores a round hole therein whose bank is engaged by the guide means to ensure circularity of the hole. And as the anchor continues to turn, the shank section enters and taps the hole until its head engages the outer surface of the wall to complete the anchor installation.

Abstract: A safety screw for skates, including a male part, provided with a first head and with a first internally threaded stem, and a female part, provided with a second head and with a second stem that has a complementarily threaded first seat for the first stem. In this screw, the male part has an axial external reeding which is adjacent to the first head and has a slightly larger diameter than the first stem. The reeding interacts with a second seat that has a slightly smaller diameter. The second seat is formed at the free end of the female part, and is contiguous to the first seat.

Abstract: A repair plug for sealable insertion into puncture holes in tires has a conical shank carrying one or more buttress threads which may extend onto a head portion adapted for rotation with a screwdriver.

Abstract: An assembly of housings is secured is secured together by a plurality of bolt members. The assembly is subject to a source of vibration, such as an internal combustion engine. To ensure the natural frequency of the bolt is outside the operating range of the engine, tolerance support rings are installed to reduce the effective length of the bolts and thereby increase the natural frequency.

Abstract: A fence system including a frame and a plurality of foraminous panels attached to the frame. The foraminous panels are constructed with continuous integral strands which are connected by integral bonds extending between each of the strands. The integral strands form a zig-zag pattern defining cell apertures therebetween. The cell apertures define a non-circular interior shape. A fastener of the fence system has a shank and a head attached to one end of the shank. A shoulder positioned between the shank and the head is shaped to cooperatively engage a cell aperture for preventing rotation of the fastener when engaged with a foraminous panel. The foraminous panels are attached to the frame with a portion of each neighboring panel having an overlapping area through which fasteners are inserted and attached. An angled top edge cap is attached along a top end of the foraminous panels and is angled to deter climbing.

Abstract: A technique for fastening together logs and a fastener therefor is directed to a self-drilling/tapping fastener which allows the fastener to be driven through the log to be secured without pre-drilling a bore. Counter-bore fins on the fastener head also form a counter-bore for the head. A lubricious coating applied to a portion of the shank accommodates settling of the logs and facilitates installation.

Abstract: The present invention discloses a screw for use with very thin sheet metal. The screw has a head and a shank which has a first and relatively very short tapered section and a second, longer, substantially cylindrical section. The first section attaches to the underside of the head on one end and to the cylindrical section on the other. The first section is broader at the end attached to the head and carries two or fewer turns of threads. The second section of the shank carries uniform threads that are continous with the threads on the first section. The underside of the head also has locking serrations which are triangular, having an included angle of 28 degrees and gradually increase in height at slope of 8-10 degrees with a length of approximately twice their height at their highest point.

Abstract: An article support rack rests on wheels fastened to walls of a washing machine tub. An axle having a partially knurled shaft is inserted through each wheel. A washer is placed over the axle to engage the knurled part and hold the wheel on the axle. The axle is secured in a hole in a wall of the tub.

Abstract: A locking fastener in accordance with the invention comprises a head or a nut body having a radially outer surface defining an outer periphery of selectible configuration and a height dimension defining an axial direction. A shank or a locking neck portion extends axially from the head or nut body and has a radially outer surface defining an outer diameter of smaller cross-sectional dimension than the outer periphery of the head or nut body. A substantially flat radially extending locking surface is defined on the head or nut body between the outer surface thereof and the outer surface of the shank or locking neck, and a plurality of raised locking ribs extend across at least a portion of the locking surface, each of the ribs being arranged angularly offset in a direction corresponding to the direction of rotation of the nut to attain advancement toward a clamped engagement, (viz.

Abstract: A fastener system for securing a multi-layer panel having a first surface adapted to be secured to a substructure, a second surface awash in a fluid flowing thereacross, and a plurality of spaced fastener-receiving holes arranged in a predetermined array in the second surface. Each fastener includes a threaded shank having a diameter smaller than any of the fastener-receiving holes, a load-bearing flange located adjacent the shank having a diameter greater than the shank diameter for pressing the first surface of the panel against the substructure, an unthreaded shank extending away from the load-bearing flange and having a diameter smaller than the threaded shank diameter, and a second flange having a diameter greater than the diameter of the load-bearing flange. The second flange is located on the side of the unthreaded shank opposite the load-bearing flange, and functions to seat against a recessed region of the second surface of the panel.

Abstract: A self-captivating screw becomes captive in a metal sheet, yet is freely rotatable after a simple pressing of the two parts. The screw is applied to the sheet by pressing against an anvil having a circular cavity in alignment with the panel aperture. The screw has an elongate shank with a head at one end and a threaded portion at the opposite end. The head and threaded portion are greater in diameter than the shank. The screw includes a displacer collar just beneath the head which, under pressure, deforms the metal sheet causing the cold flow of panel metal inward about the screw shank without gripping it tightly. The anvil cavity has a diameter greater than the major diameter of the screw threads, but less than the diameter of either the displacer collar or the minor diameter of the threads.

Abstract: A fastener is provided which is adapted to be at least partially embedded within a molded workpiece. The fastener comprises a first threaded section and a second section. The second section has a first end part defining a shoulder for making contact with a first portion of a mold during formation of the workpiece and a second end part having an outer end face for making contact with a second portion of the mold during formation of the workpiece. The second section further includes a crush-boss extending outwardly from the outer end face for contacting the second portion of the mold and thereby ensuring that the second section of the fastener is compressively engaged by the first and second portions of the mold during formation of the workpiece.

Abstract: A shape of the head part of the screw is improved and performance of insertion of the screw when punched and performance of fastening of the screw when seated as well as a finishing treatment upon completion of the fastening against a fastened member are improved. The head part is comprised of an upper large diameter part formed with a first seat surface of inverse truncated cone shape having an outer circumference of a curved concave surface and a small diameter part formed with a second seat surface of an inverse truncated cone shape concentrically and integrally connected to a lower part of the large diameter part and having its outer circumference of a curved concave surface, and an annular projecting edge is formed at a connection part between the seated surfaces of the two-stage curved concave surfaces.

Abstract: Pressure hardware for a seal block assembly used to form a modular, annular seal around a conduit passing through a wall, the assembly including elastomer seal blocks joined in an annulus around the conduit, the seal blocks having pressure bolt apertures parallel to the conduit; the seal blocks are axially compressed and radially expanded to form the seal. The assembly includes pressure hardware in sets each including a bolt, a matching nut, and a first molded resin pressure plate that has a recess large enough for the bolt head to seat in freely rotatable relation in it, with peripheral access for a wrench around the bolt head; a washer is rotatably positioned in the bottom of the recess, which is deep enough so that the bolt head does not project substantially out of the recess. The first pressure plate has a bolt-receiving aperture large enough to admit the bolt rod but small enough to block the bolt head.

Abstract: Thirty-sixth order harmonic noise generation is suppressed in an automotive-type alternator generator by forming a countersink in the leading edge of a through bolt bore to provide a transversely abutting conical surface to the flange of a through bolt which is used to retain the housing elements.

Abstract: By modifying a shape of a head part of a screw, an inserting performance when a punching operation is carried out, a fastening performance when the screw is seated, and a finishing process upon completion of fastening against a member to be fastened are improved.A seat surface of the head part is formed in an inverse truncated conical shape with its outer circumference being a curved concave surface and the upper surface of the head part is formed with a spherical concave surface. The head part is provided with a plurality of spot facing projections extending from the seat surface of the small diameter part at the lower portion of the head part adjacent to the screw shaft part along the curved concave surface of the seat surface in a longitudinal direction. The upper surface of the head part formed in the spherical concave surface is provided with chamfered portions in which an opening edge of the engaging groove of a cross-shaped hole is cut in a conical shape.