Abstract: A shearable fastener has a threaded shank (10) adapted for engagement with a threaded bore and a head (12) formed for engagement with a drive tool. The shank (10) is formed with a series of axially separated weakenings (14) defining a series of shear planes, the weakenings (14) being formed such that the applied torque necessary to cause the shank (10) to shear increases progressively from the shear plane (14) furthest from the head (12) to the shear plane (14) nearest the head (12).

Abstract: A gauge for measuring bone thickness includes an elongated pin for insertion into a bore through a bone section. The pin has a length sufficient to span the entire bone section with a distal tip protruding therefrom. The pin further has a length measurement indicator disposed along an outer surface, such as a series of colored bands or indicia, the visualization of which communicates bone thickness. The gauge also has a head at a proximal end of the pin, which is dimensioned to prevent its movement into the bone section's bore. In a particular embodiment a protrusion extending away from the pin's outer surface is provided to retain the pin within the bore. Methods are also described for measuring bone thickness and for contouring bone.

Abstract: An improved set screw, for use in an osteosynthesis apparatus to secure and fix the spinal rod in the bore of the head of a bone screw, hook, connector or the like from translational or rotational motion, which comprises a head of hexagonal external cross-section and a lower portion having a threaded outer surface. A point is centrally formed on a lower surface of the set screw for penetrating into the rod and the point is preferably surrounded by a spaced and sharpened ring. In some embodiments a peripheral notch is formed between the head and the lower threaded portion of the set screw. A cylindrical bore comprising an upper bore section and a lower bore section is formed in the set screw such that the upper bore section extends through the head and the lower bore section extends partially through the set screw lower portion.

Abstract: A connector assembly that is subjected to alternating loads by an axial flow of force between zero and various maximum values, with an outer assembly component designed as a hollow section and an inner assembly component located in the outer one and fitting by virtue of its shape. In order to detect failure of the assembly caused by a fatigue fracture produced by overloads at the end point in the assembly direction, even before it develops, in a simple fashion within the functional assembly, the assembly comprises a rear area with play that begins at the end of the connection that points in the assembly direction and a forward zero-play area of the inner assembly component that abuts the latter and is located inside the outer assembly component.

Abstract: The invention relates to an airbag apparatus including a container (11) which can be broken open, the container having a base (12) to which there is secured a gas generator (13) and a gas bag (14) which is folded together and accommodated in the container, as well as an outwardly projecting attachment element (15) for the attachment of the container (11) to a vehicle steering wheel (16). In accordance with the invention, the design is such that the attachment element (15) includes a snap fastener (18) secured to the base (12) of the container (11) that can latch directly into an associated bore (17) of the steering wheel (16). The snap fastener has a position of intended separation, in particular a position of intended fracture, between the attachment position of the fastener (15) to the container (11) and the snap means (18).

Abstract: A one piece pin, adapted to be driven by a motor, includes a threaded rod having a self drilling end at one end of the threads of the rod. The self drilling end includes a transversely positioned flat portion integral with the rod having a drilling edge with a point. A flat head is formed on the rod at the opposite end of the threads, the head having a pair of diametrically opposite notches which permit the head to be grasped by a tool. A divisible shank is attached to the heads by a zone of reduced resistance to rupture torque.

Abstract: A threaded fastener including a nut and a bolt with the nut including a ring section and a nut section with the nut section having a main body portion and a neck portion with the neck portion adapted to be moved into the ring section and to be moved radially inwardly such that the threads in the neck portion are moved into compressive engagement with the engaged threads of the bolt to provide prevailing torque structure resisting loosening of the nut member from the bolt.

Abstract: A fastener and an associated fastening method are provided to securely join at least two structural elements to form a structural assembly. Although the fastener can join a variety of different types of structural elements, the fastener is particularly well adapted to join composite panels, superplastically-formed/diffusion-bonded panels, honeycomb panels and hollow core panels since the fastener can securely join these structural elements without crushing or otherwise damaging the structural assembly. The fastener can also be mounted in blind installations, while providing a relatively smooth head following installation. In addition, the fastener can securely join structural elements while tolerating variations in the thicknesses of the structural elements.

Abstract: The invention relates to a fastening element with a torque-limiting function, comprising on the one hand a fastening member (2, 2') with working threads (4), that is to say threads which are active for the fastening function of the element, and on the other hand a gripping member (3, 3') which is arranged so as to be capable of being turned with the aid of a spanner, wrench, screwdriver or other tool for attaching the fastening element (1, 1') and connected or connectable to the fastening member (2, 2') via torque-transmitting threaded connection (5, 6/17, 18) with sufficient strength in order to be capable of transmitting to the fastening member torque of the size for which the fastening element is intended, and in which the gripping member is arranged to be unscrewed and turned relative to the fastening member, on attachment of the fastening element, only when the torque exceeds a given predetermined torque.

Abstract: A new overload protection device has been invented of the type in which components are fixed mutually by means of a safety member adapted to be cut or broken when the components are subjected to an overload, wherein the safety member is a thread spiral or spirals adapted to be cut loose from a member, rod or sleeve when the thread spiral (or spirals) is subjected to an overload.

Abstract: A hinge connects the webbing of a first bridge span to the webbing of a second bridge span. The hinge has male hinge plates on opposite sides of the first span's webbing and has female hinge plates on opposite sides of the second span's webbing. A shaft passing through the male hinge plates and first span's webbing is threaded on the ends but is smooth between the ends. Pockets at outer surfaces of the male plates surround the threaded ends and accept torque limiting nuts engaging the shaft. The nuts have heads, recess bodies and frangible necks connecting the heads to the bodies. No part of the bodies extends past the outer surfaces of the male plates. When the nuts are driven onto the shafts at a given torque, the necks break and the heads twist off. Then any remaining parts of the necks are removed. The male hinge plate can then be rotatably mounted adjacently between the female hinge plates.

Abstract: Thus, the present device provides a nut and bolt assembly having a lower threaded end and opposing upper threaded end. A first flange seats above the lower threaded end and an upper flange seats below the upper threaded end. A weak point having a known torque limit is provided below the upper flange. A nut is mounted on the upper threaded end. When the nut is turned beyond the torque limit of the weak point, it causes the bolt to break at the weak point. The bolt of the present invention is relatively inexpensive to make and use. It is designed preferably to be used in conjunction with a pressing member and a pipe junction holder for holding a pair of joined pipes.

Abstract: Anchor unit of this invention is provided with a plug which is driven into an anchor socket or sleeve to expand its split end portion by rotating a bolt which is engaged with the anchor socket or the plug by threads, in a predetermined direction. In one embodiment, the plug is a separable end portion of the bolt which is movable together with a remaining portion of the bolt when the bolt is rotated in the above described predetermined direction and twisted off or separated from the remaining portion when the bolt is rotated in a direction opposite to the above described predetermined direction.

Abstract: A traction stud for an endless snowmobile belt including an elongate rod having a ground engagable end and a threaded end which can be coupled to the track with a threaded fastener. A slot is cut into the threaded portion of the track such that the terminal end threaded portion is separated from the remaining threaded portion by a gap but coupled thereto via a reduced stem which, after installation, can be broken away so that the remaining portion of the stud shank is flush with the fastener. The invention also contemplates the method of making the stud and the method of installing the stud with a transverse slot providing a weakened break away portion which can be severed by the application of transverse force to remove the axially inner terminal end of the stud.

Abstract: A non-removable, tamper-proof bolt has a threaded shaft, a permanent head, and a torque head which is sheared off from the assembly when the bolt is fastened. The shaft has an opening formed therein at the forward screw end, and the opening has a profile for engagement with a torque tool. The torque head is formed with a hole as well which extends through the entire torque head coaxially with the threaded shaft. The torque head is attached to the permanent head by the intermediary of a bridge defined around said hole in the torque head. Once the torque head is sheared off, the bolt cannot be turned until the opening formed in the forward screw end is exposed by drilling through the shaft from the permanent head inwardly.

Abstract: A method of producing an intended breaking point at a predetermined location of a tension member for a soil anchor of a strain-hardened steel or a steel which is not which is not in a thermodynamic equilibrium, for example, a wire or a steel wire strand, to enable removal of the free steel length after use by applying a tensile force which exceeds the working load. The predetermined breaking point is obtained by heating the tension member at a predetermined location in a controlled manner to a temperature at which the state of strain-hardening or the state of being not in a thermodynamic equilibrium is at least partially cancelled, wherein the predetermined breaking point has a breaking load which is equal to or smaller than the breaking load of the untreated tension member, but greater than the yield point of the untreated tension member.

Abstract: A fastener assembly for permanently securing together a pair of mating panels having aligned apertures therethrough including a bolt having an enlarged head at one end, a threaded shaft portion at the other end and an integral main body portion interconnecting the head and the shaft portion, a split ring bushing encircling the bolt, a first nut threadably mounted on the bolt having deformable protrusions thereon and a second nut threadably mounted on first nut also having first deformable protrusions thereon, both sets of protrusions being deformable at a predetermined load thereon into the threads of the bolt and the first nut respectively, the first nut being forced against the bushing when threaded on the bolt and the second nut abutting against an underside of one of the panels when threaded on the first nut thereby providing a mechanical lock between the deformed protrusions and the mating threads permanently locking the panels together.

Abstract: The invention relates to a set screw having a self-limiting external torque head. The head has a hexagonal external cross-section and an internal bore which extends through a necked portion. The necked portion joins the external torque head to the threaded screw portion of the set screw. The necked portion has a cross-sectional thickness and strength to provide for shearing at a predetermined load limit, such as from about 54 to about 64 pounds per inch. The threaded screw portion has an internal hex to allow for the internal application of loosening torque at about two-thirds of the tightening torque limit, i.e., to provide a loosening torque of about 40 inch-pounds. The screw member includes a high-compression, rod-contacting surface such as a knurled surface.

Abstract: A tamper proof threaded fastener construction (10) comprising a conventional elongated threaded fastener body member (20) having an enlarged head member (30) provided with a contoured and tapered frangible member (40) which is used to drive the fastener construction (10) in a rotatable fashion, and when the frangible member (40) is removed leaves an irregular surface (45) which prevents the fastener construction (10) from being rotatably driven in any direction.

Abstract: A vehicle steering wheel assembly (20) includes an air bag module (24) connected with a frame (42) of a vehicle steering wheel (22). The module (24) includes an inflator (62), an air bag (64), and a mounting hub (66). An internal groove (184) in the mounting hub (66) receives resiliently deflectable tabs (208) on the inflator (62) to secure the inflator to the mounting hub. A mounting portion (240) of the air bag (64) is received in one section of an external groove (182) on the mounting hub (66). A base portion (262) of a guide ring (260) is received in another section of the external groove (182). A wall portion (266) of the guide ring retains the mounting portion (240) of the air bag (64) in the groove, to secure the air bag to the mounting hub. The steering wheel frame (42) has a plurality of tabs (164) which are deformed into slots (162) in the mounting hub to secure the module (24) to the frame.

Abstract: A fastener system includes an applicator for engagement by a tool, and a fastener such as a screw having a first surface with first screw threads in a one hand direction for engaging a workpiece. An attachment mechanism is provided to transfer rotational force from the applicator to the fastener and has second and third screw threads in an opposite hand direction to the first screw threads. The second and third screw threads are interfaced to establish a torque of the predefined magnitude prior to the fastener being attached to the workpiece. When the torque applied by the tool exceeds the predefined magnitude, the attachment mechanism begins to unthread and further application of torque from the tool to the fastener ceases, thereby controlling the applied torque to no greater than the predefined magnitude. The attachment mechanism can be used in a variety of applications including flush mounted heads, shallow aperture installations and multistage torque mountings.

Abstract: A pre-load indicating washer for properly tensioning a joint held together by an externally threaded member and an internally threaded member. The pre-load indicating washer has a plurality of protuberances, struck and partially sheared from the annular body of the washer, which are pushed under load back into a corresponding number of indentations in the annular body which are formed when the protuberances are formed. The protuberances of the pre-load indicating washer are curved in outline with no portion of the protuberances extending radially outward beyond the outer periphery of the bearing surface of an externally threaded member when the pre-load indicating washer is positioned adjacent the externally threaded member, or radially outward beyond the outer periphery of the bearing surface of an internally threaded member when the pre-load indicating washer is positioned adjacent the internally threaded member.

Abstract: A nut and bolt assembler comprises a threaded bolt (78a) having a proximal end (140) with a knurled outer surface (142). A nut (144) is press fit onto the bolt knurled proximal end (190) to prevent rotation of the nut (144) with respect to the bolt (78a). Preferably, the knurled outer surface preferably comprises axial splines (142). The connection is most useful on the proximal end of a caging bolt (78a) in a spring brake actuator (10) having a hollow actuator rod (60) into which a head (86) at a distal end of the caging bolt (78a) is positioned with the proximal end (140) of the caging bolt (78a) extending out of the brake actuator through a threaded aperture (77) in an end portion of a brake actuator housing (52). A washer (148) can be provided between the nut (144) and the brake actuator housing (52) to prevent foreign material from entering the break actuator housing (52) through the threaded aperture (77).

Abstract: An unlockable connecting device between two objects is provided. The device includes a connecting member for connecting the objects when the device is in a connected state, and an elastic system for applying to the connecting member a tensile stress for breaking the connecting member when the device is in a separation state. The tensile stress is caused by expansion of the elastic system as a result of elastic resiliency of the elastic system.

Abstract: A screw comprising, in succession between a first end and a second end thereof: a first polygonal head; a breakable neck; a second polygonal head; and a threaded shank; the diameter of the breakable neck being smaller than the diameters of the heads and of the shank, the screw further comprising a cylindrical bearing surface portion situated between the breakable neck and the second head, and having a diameter not less than that of the breakable neck, but less than that of the second head. A tool for tightening such a screw comprises a tightening endpiece including resilient means that project radially into the inside of the tube while they are in the free state, and that are capable of retracting to allow the first head of the screw to be inserted as far as the engagement portion of the tube and to co-operate with the cylindrical bearing surface portion of the screw when the first head thereof is in said engagement portion.

Abstract: The present invention is directed to a bolt with shearable head (1) with an external thread section (15), a head section (3) and a taper section (7) forming a predetermined breakage point (6), provided for between the external thread section and the head section, as well as an end section providing a clamping contact (9). Furthermore, there is provided a threaded bush (15), extending at least partly along the external thread section (5) and having in turn an external thread (17).

Abstract: Fastening plug (10) made of plastic for fastening in a corresponding bore, especially for fastening furniture hardware on furniture, with an elongate stem portion (14) which can be releasably fastened on the associated hardware piece, from whose outer circumferential surface a number of annular projections (16) offset lengthwise on the stem having a triangular cross section tapering outwardly, each forming a knife-edge-like holding burr (18). The outside diameter of the holding burr is greater than the diameter of the corresponding bore, while the stem portion (14) has between the first annular projection (16) on the hardware end and the end facing the hardware a neck (20) whose diameter is smaller than the diameter of the corresponding bore.

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 pre-load indicating washer in which a plurality of protuberances, struck and partially sheared from the annular body of the washer, are pushed under load back into a corresponding plurality of indentations in the annular body which are formed when the protuberances are formed. The mass of material defined by each protuberance/indentation pair is concentrated along the lengthwise central region of the protuberance/indentation pair, thereby stiffening the protuberance, so that when load is applied to the washer, the protuberance will first undergo elastic deformation prior to collapsing back into the indentation from which it was formed.

Abstract: A breakable bolt assembly comprising a pin member, a collet member and a thumb knob member. The assembly is designed to mount without the use of hand or power tools, and features a pin member which breaks apart when the shear force on it exceeds a predetermined magnitude. The pin member comprises an elongated pin body and a pin head. A proximal length portion of the pin body has a plurality of flutes transverse to the length of the pin body and spaced from each other by ribs. The diameter of the pin body at the flute most proximate the pin head is smaller than at the more distal flutes. Thus, shear force is transferred to the most proximal flute, and when the force exceeds a predetermined magnitude, the pin member breaks apart at the juncture of the pin body and pin head. The collet member has an internal passage for receiving the distal end of the pin member, and is compressible around the pin member.

Abstract: A break-way coupling with spaced weakened sections includes a central controlled breaking region and rigid threaded bolts at each end for connection to a base at one end and to a pole or the like at the other end. The controlled breaking region includes two axially spaced necked-down portions of smaller diameter and solid cross-section. Where the axil length of the controlled breaking region is L and the necked-down portions have a diameter D, the dimensions D and L are selected so that the ratio D/L is within the range D/L.ltoreq.0.3. The necked-down portions have conical tapered surfaces to insure that at least one of the necked-down portions break upon bending prior to contact between any surfaces forming or defining the necked-down portions.

Abstract: A rockbolt for anchoring in a borehole and then tensioning it has a nut at its distal end whose screw threaded engagement with the rockbolt is utilised to force the nut against the surface at which the borehole is provided and cause tensioning of the rockbolt. Initially, the nut cannot be run down the rockbolt owing to provision of a disc seated in a recess at the distal end of the nut and which is only forced out from the recess when the nut is subject to a minimum predetermined torque. Holding of the disc in the recess is achieved by deformations of the nut resulting in the perimeter of the disc being frictionally restrained.

Abstract: A fastener assembly for anchoring masonry to a wall support stud includes a sealing member releasably seated in a retaining groove. The fastener threads into the support stud and is affixed to a hole in the masonry with a bonding agent. The retaining groove holds the sealing member in place during the installation of the fastener, and a break-off groove enables the fastener to be severed inside the masonry. After the fastener has been severed, the sealing member can be relocated inside the masonry to a pre-determined sealing position, thereby insuring the use of a controlled volume of bonding agent.

Abstract: A fastener which releasably retains a first member in relation to a second member. The fastener is frangible for fracture upon the application of a tensioning force thereto permitting the first and second members to which the fastener is engaged to be displaced relative to one another. The fastener, once fractured, is retained in the corresponding first and second members to which it was originally attached to prevent the generation of loose pieces. An installation tool is also provided for installing the fastener into the first and second members. The fastener includes a shank which fractures into a first and a second segment. A frangible portion of the fastener is spaced along the shank between the first and second segments and defines such segments for providing a predetermined fracture point. Non-planar engaging portions on the first and second segments retain the fastener in the corresponding first and second members once engaged therewith even after fracture of the fastener.

Abstract: A puzzle is disclosed which includes an elongated left-hand threaded bolt carrying a split lock washer and having a nut at one end. The other end of the bolt is partially threaded into a second nut which has a short length of another bolt threaded at its end. The object of the puzzle is to figure out how to remove the lock washer from the bolt.

Abstract: A fastener, such as a machine screw or bolt, designed with a double head, one located above the other, which when tightened by means of the upper head will, when tightened to a specifically desired amount of inch or foot pounds of torqure, over the amount of torque required to apply the main part of the fastener to the desired degree of tightness will shear the upper head from the lower head, automatically torquing no more than desired. The lower head has a conical shape so as to provide a minimum surface to preclude removal by gripping with pliers, a wrench, or screwdriver. This is effected by having the angle between the surface of the cone and the base of the cone advantageously no more than 35.degree., preferably no more than 30.degree. or less. This ultimately provides a tamper-proof fastener with total automatic torquing capabilities.

Abstract: Novel preset, calibrated stud bolts and spring-loaded nut assemblies with torque-off spline tips for securing structural conduit units and the like, and method of calibrating the same.

Abstract: A torque limiting bolt for tightening by a power wrench comprises a threaded shank, a tightening head at one end of the shank, a retaining head at the other end of the shank and a nut in threaded engagement with the threaded shank, the tightening head being an eight point head having sixteen external facets of equal size and uniform spacing around the circumference of the head. The power wrench is provided with oppositely rotatable inner and outer sockets engaging the driving head and the nut, respectively, the inner socket being an eight point socket having sixteen internal facets.

Abstract: An electrical wire connector (10) has a C-shaped body section having arcuate ears (22) laterally therealong and converging from a wide end to a narrow end and forming wire grooves (24), a wedge having converging concave side surfaces (32) forming wire channels opposing wire grooves (24) when inserted into the wide end of the C-shaped member (12), and a shear head drive bolt (50) for urging the wedge (14) into the C-shaped member upon actuation to compress and thus interconnect respective wires (16,18) placed along the wire channels. The drive bolt (50) has an outer hexagonal head (54) joined to a smaller inner hexagonal head (56) at a frangible section to be sheared off upon achievement of a selected torque level which assures interconnection of the wires when attained.

Abstract: An expansion anchor assembly comprising a shell having three elongated vertical leaves of generally transverse arcuate configuration arranged to form a 360.degree. surface, the exterior of each leaf being provided with a gripping surface, each leaf being attached at its top to a bail, the bail comprising a solid top portion having a frangible central dome through which a rock bolt can be forced, the interior diameter of the dome being adapted to receive the top end of the rock bolt, the top end of the rock bolt being chamfered to ensure that it remains secure within the central dome during installation and to prevent lateral movement of the rock bolt relative to the anchor shell, and a wedge-member being threadably engagable with the rock bolt and being adapted so that on longitudinal movement of the wedge-shaped member away from the ball, the leaves are wedged apart and relative rotation between the leaves and the wedge member is prevented.

Abstract: A composite threaded collar is fabricated from a panel consisting of multiple layers of fiber reinforced tape, bonded together to form a rigid composite structure. The tape comprises a plurality of longitudinally extending continuous fibers that are joined together by a suitable bonding agent. The stack of properly oriented tape layers is heated while a compressive load is applied, followed by cooling. The rigid panel thus formed is then cut, tapped and machined to form the desired configuration of the collar. A twist off driving portion of the collar will shear between tape layers at an annular notch at a predetermined torque.

Abstract: Tamper proof service bolts for sealing boxcars, automobile hoods, gates and other enclosures, as well as gas and electric meters, railroad switches and the like. In a first preferred embodiment the tamper proof service bolts are characterized by special head service bolts, each having a base member and a collar secured to the base member by means of a connecting bolt having a specialized head recess for receiving a corresponding tool which is required for removing the connecting bolt and the collar from the base member. In another preferred embodiment of the invention retainer clip service bolts are provided, wherein a retainer clip is adapted to mount on each base member and in the collar when the collar is fitted over the base member, to secure the collar on the base member.

Abstract: In order to simply and economically fix to an internal-thread coupling (12) a pipeline (17) furnished with two slidable external-thread connections (15, 18), the invention contemplates fabricating the two external-thread connections (15, 18) together in the shape of one part only. At a predetermined screw-in torque, one external-thread connection (15) is torn off and as a result one pipeline end (16) is safely retained in the internal-thread coupling (12). The second external-thread connection (18) may be slid to the second end (21) of the pipeline and can fix the latter to a further internal-thread connection. The fixing means and methods contemplated by the invention are automation compatible and, upon fixing, protect the pipeline from being detached from the coupling through faulty handling.

Abstract: Provision is made for a container which stores and shields radioactive material. Included in the container is an enclosure defining a hollow chamber in which radioactive material is storable. A closure assembly cooperates with the enclosure in such a manner that an internal plug thereof effects a preselected gas-impervious sealing engagement. The closure assembly includes a lug which is rotatable to urge the assembly into sealing engagement and which torsionally fails following achievement of the desired sealing engagement of the closure plug to thereby prevent the lug from being subsequently used to open the container. The container and closure members provides desired radioactive shielding.

Abstract: A pre-load indicating washer in which a plurality of protuberances, struck and partially sheared from the annular body of the washer, are pushed under load back into a corresponding of indentations in the annular body which are formed when the protuberances are formed. The walls of the protuberances and the walls of the indentations are arranged so that when the protuberances are "collapsed" back into the indentations, there is minimal frictional resistance as the walls of the protuberances slide past the walls of the indentations.

Abstract: An extended counterbore nut has a nut body and an attached collar extending from counterbore in the nut body. The bore of the collar is about equal in diameter to the major diameter of the thread of the bolt used with the nut so that the collar aligns the bolt and nut for threading. At a predetrmined axial load, the collar releases from the nut body and enters the counterbore, shortening the nut.

Abstract: An anchoring device for a tension member of an earth- or rock anchor, where a support element transmitting the tensile force is arranged between an anchoring element undisplaceably connected with the tension member and an anchor plate abuttable against a support base, the support element includes a cylindrical hollow body surrounding the anchoring element, whose inner wall has in its lower region projections protruding inward beyond its inner contour, against which the anchoring element abuts in a force-transmitting manner with partial regions of its cross-sectional area. If a predetermined tensile force is exceeded, the support element and/or the anchoring element can plastically deform in the region of their inter-engaging surfaces, so that a relative displacement occurs in axial direction.

Abstract: A breakable composite drill screw comprises a first shank made of a metal unsusceptible of hardening, a driving head extending from one end of the first shank and engageable with a screw driving tool, a second shank made of another metal susceptible of hardening, the second shank being fixedly adjoined to the other end of the first shank to thereby provide a break zone at said other end, a drill bit formed by cold forging at an end of the second shank, a continuous thread formed by thread-rolling to extend around both outer cylindrical peripheries of the first and second shank wherein a portion extending from the break zone to the drill bit is hardened or quenched, and wherein said shanks are adjoined at their engaging surfaces to each other by projection-welding technique making use of a welding lug protruding from either engaging surface, said lug forming the break zone.

Abstract: A threaded fastener has a pin with a head, a cylindrical shank, a shoulder with reducing diameter, a radius at the least diameter of the shoulder whose region is work-hardened, and a threaded end, in that order. The thread extends into near-adjacency to the shoulder, and has no more than approximately one-half of a convolution of an incomplete thread at its end adjacent to the shoulder. A collar is threadable onto the thread. It has a counterbore no longer than the anticipated grip range plus approximately one-half of a thread pitch. The collar may be inherently torque-limited. The term "thread" also includes a peripheral groove.

Abstract: A breakable composite drill screw comprises a first shank made of a metal unsusceptible of hardening, a driving head extending from one end of the first shank and engageable with a screw driving tool, a second shank made of another metal susceptible of hardening, the second shank being fixedly adjoined to the other end of the first shank to thereby provide a break zone at said other end, a drill bit formed by cold forging at an end of the second shank, a continuous thread formed by thread-rolling to extend around both outer cylindrical peripheries of the first and second shank wherein a portion extending from the break zone to the drill bit is hardened or quenched, and wherein said shanks are adjoined at their engaging surfaces to each other by projection-welding technique making use of a welding lug protruding from either engaging surface, said lug forming the break zone.