Abstract: A sealing fastener, which expands by the insertion of preferably a screw. The fastener comprises a substantially flat and two expandable legs. The head has an upper side and a lower side, preferably separated by a gap. The fastener has further an elastic body molded at least on the lower surface of the head. A large unexpected improvement is achieved by having the elastic body also molded in the gap between the upper surface and the lower surface.

Abstract: The invention relates to a rivet device. The device is characterized in that it comprises a substantially cylindrical tubular body (10), an annular collar extending outwards from the first end of the body, and at least two locking elements (20, 22) formed in the body. Each locking element is constituted by an elastically deformable strip (24) cut out in the body, extending in the direction of the axis of the body, and having a first end secured to the first end of the body and a second end secured to the second end of the body, with each strip having folds (30, 32, 34) in such a manner that in an initial state a portion of the strip projects into the inside of the body and in a deformed state the strip projects to the outside of the body.

Abstract: An expansible anchor for anchoring in a hole drilled in a component has a shank having a rear end provided with a structure for fixing an article and a front end provided with at least two portions of reduced cross-section with adjoining expander cones, expansible sleeve with a structure including an expansible sleeve positioned over each of the portions of reduced cross-section, at least two convex beads mounted on the expansible sleeve with a structure and projecting radially outwards, each of the beads being provided with at least one opening, and the two portions of reduced cross-section having different diameters.

Abstract: The invention relates to a metal fixation insert for stiffening the fixation zone of a part of plastic material on a support. This metal fixation insert is made of rolled steel which is perforated.

Abstract: An encapsulating grommet for use with a push-pin for retaining a covering panel or other structure to a supporting panel is molded in an open condition and includes a hinge portion which permits one half of the encapsulating grommet to be folded against the other half. One of the two halves includes a rectangular frame having an opening surrounded by an umbrella-like flange. The other half snap-fits into the rectangular frame when closed so that the encapsulating grommet may be shipped in a closed condition. One of the two halves has a single side wall, while the other half has an inner and outer side wall separated by a channel. When the two halves are closed upon one another, the single side wall fits into the channel, whereby a labyrinth seal against dust and water will be provided for the internal cavity of the encapsulating grommet.

Abstract: A metal dowel for anchorage in a wall panel, said dowel being made from a folded blank of sheet metal and comprising a pair of flat leg members folded over at one end to lie flat against each other, the legs tapering toward the folded end to form a pointed end to the dowel and being held together at said folded end by a breakable web formed by the fold between said legs. The leg members are fixedly connected together at the opposite end to form a head end to the dowel and a threaded hole is formed out of and located between the legs adjacent the head end of the dowel with a funnel-shaped recess formed out of and located between said legs being axially aligned with said threaded hole and located between the threaded hole and the pointed end. After insertion of the dowel pointed end first into a panel, threading of a threaded member into the threaded hole with the tip thereof entering into said recess, breaks the web and forces the legs apart to anchor the dowel in the panel.

Abstract: The expansible anchor consists of a shank having a threaded portion for fixing an article at its rear end and a reduced cross-sectioned portion with an adjoining expander cone at its front end, and, positioned over the reduced cross-sectioned portion, an expansible sleeve having longitudinal slits forming expansible segments and locking elements protruding beyond the diameter of the expansible sleeve and arranged on the expansible segments. To increase the holding force of the anchor and to allow the expander cone to slide-up and the expansible sleeve to expand in operation if the drilled hole become enlarged as a result of cracks forming, the locking elements consist of several interconnected punched elements on each expansible segment extending in a longitudinal direction of the expansible segments. Each punched element is triangular with a point directed towards the front end of the expansible segments.

Abstract: The present invention is a system for supporting rock within a mine having a bore hole. The system comprises a mining bolt having a round metal tube which has a completely hollow interior and all cross sectional dimensions less than that of the bore hole. The metal tube has a first end and a second end which are swaged closed to permanently close off the completely hollow interior so the bolt can crush and deform during movement of the rock when in place therein. The swaged second end has a square cross section to allow a tool to turn the mining bolt in the bore hole from the second end. The mining bolt has a metal washer flange fixedly attached to the metal tube adjacent to the swaged second end. The system also comprises a bearing plate disposed between the rock and the flange and a resin cartridge for bonding the mining bolt to the rock within the bore hole.

Abstract: An expansible anchor for anchoring of an article to a component includes a shank having a portion of reduced cross-section at a front end, elements for fixing the article at a rear end, an adjoining expander cone at a rear end of the shank, and an expansible sleeve positioned over the shank portion of reduced cross-section and locking elements projecting beyond the diameter of the expansible sleeve. To allow the expander cone to enter the expansible sleeve for expansion of it even in the event the drilled hole becomes enlarged as a result of cracks being formed in its wall, the expansible sleeve is provided with a plurality of longitudinal slits so as to form expander arms. Each of the longitudinal slits extends over at least half the length of the expansible sleeve from a front end edge of the expansible sleeve and continues into an enlarged opening provided in the sleeve.

Abstract: A device to detachably connect two, e.g., plate-shaped subassemblies, includes a control element with a projecting retaining portion which can be inserted into aligned openings of the subassemblies and with a head portion to be braced against the first subassembly. The projecting retaining portion has at least one lateral first recess to receive and engage with at lest one locking element of a holding element. The locking element yields flexibly and resiliently when inserting the control element into the holding element. The holding element also has expanding elements to brace against a rear side of the second subassembly. Both the control element and the holding element can be inserted individually in succession or together from a front side of the first subassembly into the aligned openings. The holding element with the expanding elements can be inserted into the openings.

Abstract: A connecting element for joining a structural part with an adjacent structural part has several sleeves (71, 72) provided with respectively one cutout (77) and one extension (74) wherein in each case the extension (74) of one sleeve (71, 72) engages into the cutout (77) of the other sleeve (71, 72). The sleeves (71, 72) are in contact with fitting clearance with an inner wall of a pipe (14) to be attached to a connector (13). A clamping screw (7) is threaded into a thread (9) of the connector (13) and thereby clamps the sleeves (71, 72) mutually in place, the extensions (74, 87) entering more deeply into the cutouts (77, 92) and thereby expanding the circumference of the sleeves (71, 72) until a fixed clamping of the sleeves (71, 72) against the inner wall is achieved. The sleeves (71, 72) are held in flush mutual contact by a serration. The unwound of the sleeves (71, 72) are punched out from steel strip and subsequently formed into cylindrical sleeves (71, 72).

Abstract: A screw or nail sustainer comprising a tube having a chamber for inserting a screw or nail into a base opening of the chamber, at least one fluid flow opening formed with a base portion of the tube for injecting a liquid resin, and at least one ring-like projection formed with a portion of the tube remote from the fluid flow opening toward a tip of the tube to project from and to surround a periphery of the tube. A plurality of bag forming wings are provided with the tip portion of the tube to project radially. The bag forming wings are bent toward the base portion of the tube when the screw or nail sustainer is inserted into a hole of a board so that a bag like portion may be made in cooperation with the outer surface of the tube so as to make an opening toward the base portion of the tube.

Abstract: The fixing element for securing an article on a base material includes a shank having a shank portion for receiving an article to be fixed, a reduced diameter portion having opposite ends including a free end and an expander cone located at the free end; and an expansible resilient sleeve received on the reduced diameter portion and having at an end remote from the expander cone lugs which are bent inwards at one obtuse angle. The lugs have end surfaces facing a transition shoulder between the other end of the reduced diameter portion and the shank portion. The expansible resilient sleeve has a length greater than the length of the reduced diameter portion. The expandsible resilient sleeve also has, in an unstressed condition, a sleeve outer diameter larger than the shank portion diameter and a sleeve inner diameter larger than said reduced diameter portion diameter.

Abstract: An expansion anchor capable of being expanded by thrusting a lock plug into a contacted portion to spread a clamp member having acutely angular peripheral edges. When the anchor is expanded within a hole in a rigid material such as concrete, the angular edges of the clamp member bite into the rigid material, so that the anchor is no longer removable from the rigid material.

Abstract: The mounting stud of an accumulator is secured within a central opening of a base pan mounted elastomeric grommet by way of a metal sleeve having outwardly extending protuberances that grip the inner walls of the elastomeric grommet and inwardly extending protuberances that grip the threaded stud. The protuberances are angled in such a way that both the stud and the sleeve are easily inserted into their mating component but subsequent removal is substantially prevented.

Abstract: In rock or roof bolts, in particular combined rigid profile and stretch or strain roof bolts, the bolt bar, except for the bar tip is surrounding by a sheathing tube and the end thereof projecting out of the drillhole mouth is made tensionable with respect to the rock by means of an anchor plate and a screw means. To ensure the immediate loadbearing capability of such a roof or rock bolt, in particular in the filling mortar method, at least one portion (5) of the sheathing tube (3) is provided as expansion element with cutouts (7) distributed into slots (8) and the bolt tip (2) is formed as abutment.

Abstract: A fastening element particularly adapted for use in conjunction with a mandrel for opening the expandable sleeve of the fastening element into secure relationship with a wall having a hole into which the fastening element is inserted. The sleeve is designed to provide a radial channel for enveloping the plate member adjacent the hole. The mandrel becomes a part of the fastener and offers good resistance to shear forces and also provides the means for removing the fastening element as well as fixing it to the object to be fastened.

Abstract: An anchor adapted for insertion in a hole through the wall. The wall includes inner and outer surfaces with the hole extending inwardly through the wall from the outer surface of the wall to the inner surface of the wall. The anchor comprises a head, a body, and a passage through the head and body into which a fastener, such as a screw, is adapted to be inserted. The passage has a central longitudinal axis. A surface on the head is engageable with the outer surface of the wall when the body of the anchor is inserted in the hole. At least one resiliently flexible leg extends axially of the body and terminates in a free end moveable generally radially inward and outward relative to the central axis of the body. The anchor also has a holder adjacent to the free end of the leg. The holder projects laterally outwardly from the leg. The leg is adapted to resiliently flex generally radially inwardly as the body is inserted in the hole to a point where the holder exits the hole on the inside surface of the wall.

Abstract: The bolt assembly comprises a traction shaft 1 with an anchoring extremity 13, an expansion ring 2 formed by means of expansible leg elements 18,19, and a brace 3 disposed around the shaft 1 and supported against a shoulder 24 provided upon the expansion elements 18, 19 in order to provoke expansion of leg portions 22, 23 with an undercut portion of an anchoring hole. The expansion elements 18, 19 extend between the shaft 1 and the brace 3 so as to give the latter a bearing surface of the same length as the legs 22, 23. The shoulder zone 24 defines an articulation region for the legs 22, 23.The bolt assembly is used for the fixing of pieces within a zone subject to tensile forces within a building material.

Abstract: An anchor comprising a bolt having an upper cylindrical part with an outer thread adjacent its top and a lower conical head, and a sleeve surrounding the bolt, the sleeve comprising an upper cylindrical portion and an annular expander, the expander having multiple slits therein which open to the bottom end and extend axially. The slits form expansion pieces therebetween having curvatures which, before expansion of the pieces, are substantially the same as the curvatures at the corresponding positions of the outer peripheral wall of the conical head, which the pieces contact after expansion.

Abstract: A cone expansion wall-plug is provided comprising a shank (1), a spacer (13) disposed about the shank, an expandable socket (4) and, at the end (5) of the shank (1), a cone (3) for expanding the socket (4). In order to be able to secure an object to be fixed against the edge of the anchorage hole formed within a supporting material for housing the wall-plug, the socket (4) includes a compressible zone (8) in the form of a bellows and bent lugs providing expansion and guiding teeth (10). The socket (4) is formed by die-stamping a metal sheet blank.

Abstract: An expansion dowel includes an axially extending sleeve with a leading end and a trailing end. The sleeve is conically shaped for at least an axially extending portion from the leading end with the conically shaped portion diverging outwardly toward the trailing end. Axially extending projections protrude outwardly from the outer surface of the conically shaped portion of the sleeve and have at least one axially extending flank with a planar surface inclined relative to the axis of the sleeve. The at least one inclined flank forms a working surface which acts against any pulling out force on the sleeve and ensures high anchoring values.

Abstract: A suspension peg is provied in which the wire, obtained by die stamping a metal strip and bonding the same, forms a securing eye and has at its end, to be introduced into an anchorage hole, a cylindrical portion formed by two shells and a truncated expansion cone adapted for cooperating with an expandable anchorage socket under the action of a retractive force exerted upon the eye.

Abstract: An improved wall fastener for hollow walls,the fastener having two spreadable anchoring blades designed to spread behind the wall following insertion of a screw thereinbetween. The fastener is made of thin sheet metal which has been hardened through a heat treating process, such as quenching. Complementary engaging means on the blades are used to hold the blades together during the heat treatment and to prevent the separation thereof until the screw insertion.

Abstract: An expansion peg is provided including a tubular socket threaded at one end, and having a split and expandable portion at the other end thereof which is disposed inside the socket. A first wedge intended to come into abutment against the bottom of an anchorage hole and a second wedge detachably secured to the first wedge and intended, under the action of a striking tool, to become disengaged from the first wedge and to cooperate therewith for causing expansion of the split end of the socket, is disposed within the socket and split end portion thereof.

Abstract: A retainer includes a cylindrical sleeve projecting downwardly into a hole in a plate with a flange at the lower end of the sleeve engaging the underside of the plate. Resilient fingers struck out from the sleeve engage the top of the plate to cooperate with the flange in holding the sleeve in place. A fastener initially is threaded along dimples in the sleeve to hold the fastener while permitting the latter to be threaded down into a member beneath the plate. As the fastener is threaded down, its head engages the sleeve which is crushed between the head and the plate so as to be out of the way.

Abstract: A lock bolt is disclosed for introduction into a through hole in a structural component. The lock bolt generally is a one piece tubular bolt member having a shank with two sections joined at a first end by a bridge and with a resilient locking member integral with a first of the two sections at a second end and extending within the bolt shank and then radially outward of the bolt shank at the second of the two sections to define an end portion to in conjunction with an abutment on the bolt secure the bolt in the through hole.

Abstract: An improved wall fastener for hollow walls, the fastener having two spreadable anchoring blades designed to spread behind the wall following insertion of a screw thereinbetween. The fastener is made of thin sheet metal which has been hardened through a heat treating process, such as quenching. Complementary engaging means on the blades are used to hold the blades together during the heat treatment and to prevent the separation thereof until the screw insertion.

Abstract: An expansion shell is formed from a single piece of sheet metal consisting of two spade-shaped leaves connected by a narrow portion which becomes the bail. The leaves are corrugated along their transverse axes so as to form a series of undulations of increasing amplitude and the leaves are formed into semi-cylinders. The corrugated semi-cylindrical leaves are centrally slotted along their longitudinal axes so as to form four leaf segments. The corrugated leaf segments are then compressed along their longitudinal axes so as to cause the undulations to form a tapered pleated metal fold, wherein the crests of the undulations become semi-cylindrical ridges capable of gripping the rock formation.

Abstract: A screw grommet comprises a pair of flange halves, a pair of leg halves depending from the respective flange halves and a small thickness portion connecting the lower ends of the leg halves. When fitting the screw grommet, the leg halves are thrust into a panel opening and then a tapping screw is screwed into the threaded grooves to separate the leg halves from each other while their opposed surfaces remain parallel so that the screw grommet is reliably secured to the panel. Thus, the screw grommet is adaptable to tapping screws having different diameters and also to panels having different thicknesses or openings of different diameters.

Abstract: A blind rivet having an easily settable secondary head with the rivet body having a plurality of longitudinally extending circumferentially spaced weakened areas terminating in spaced relation from the rivet flange and the open end of the rivet so that upon setting, the rivet body separates at the weakened areas to form a plurality of outwardly extending deformed areas for an enlarged secondary head on the rivet.

Abstract: An expansion dowel is made up of an expansion sleeve and an expansion body with a radially outer conically shaped surface. To expand the sleeve, the expansion body is pulled into the leading end of the sleeve. The leading end of the sleeve is connected to the expansion body by two elongated webs. A bridge section on the end of each web forms the connection to the expansion body and the bridge section is breakable under expansion conditions. The expansion dowel can be formed from a single blank of sheet metal in a forming operation.

Abstract: An anchor having a shank, a reduced neck portion on the inner end and a tapering portion, and engagement means on the outer end and having a one-piece wedging collar arranged around the reduced neck portion, and having an overlapping portion extending partially up the tapered portion, and such collar having a leading and a trailing end and an axial slot extending part way therethrough from the leading end, near the tapered portion and terminating at a bridge portion, near the trailing end and at least two generally dome-shaped bosses formed in said collar, extending outwardly, and defining a maximum spacing there between greater than the diameter of the shaft shank of such anchor, the bosses being located between the leading end, and the bridge portion, on either side of the axial slot.

Abstract: An expansion dowel includes an axially extending expansion sleeve and an expansion member rolled from a section of sheet metal. The sleeve has a leading end and a trailing end and the inside surface of the sleeve is threaded for an axially extending section from the trailing end. The thread is formed before the sheet metal is rolled. To assure there is no misalignment of the thread along the butt joint, tangs and recesses are formed along the edges of the butt joint so that the edges interengage one another when the sheet metal section is rolled. By interengaging the butt joint edges, the sleeve does not expand circumferentially when a bolt is threaded into the trailing end of the sleeve.

Abstract: An expansion dowel assembly is made up of an axially elongated generally cylindrically shaped dowel body and at least one wedge-shaped expansion member formed monolithically with the dowel body. The dowel body has a first or leading end which is inserted first into a borehole within which the dowel body is to be anchored and an opposite second end. A severable web connects the expansion member to the first end of the dowel body. Before insertion into a borehole, the expansion member projects outwardly from the exterior surface of the dowel body. When the expansion dowel assembly is inserted into a borehole, the web is broken and the expansion member, now separated from the dowel body, is displaced away from the first end within a wedge-shaped recess in the exterior surface of the dowel body.

Abstract: The disclosure concerns a fixing device for securing fasteners such as bolts into concrete or other similar material. The device comprises a sleeve member (2, 4) having a block portion (6) in which a nut (14) is set. The block portion (6) has a frusto-conical extension portion (16) joined by shearable links (18) to an intermediate portion (20) of the member which has an internal frusto-conical surface (22) complementing the extrusion portion (16) of the block portion. Tightening the bolt shears the links in the usual way. According to the present invention the device is moulded in two longitudinally divided portions (2) and (4), hinged together by a plastics hinge (10) adjacent the block portion (6). In the as-moulded conditions the portions (2, 4) are arranged end-to-end, but are hinged together to form the device ready for use.

Abstract: A blind screw anchor, made of one piece of metal, has a shank, constituted by sleeve portions connected together by uniformly spaced links. A head flange is integrally connected to an adjacent sleeve portion at one end of the shank by a bridge piece bent at right angles to bring the head flange against the shank at that end. A tail cap piece is similarly connected to the sleeve portion at the other end of the shank and bent into abutting engagement therewith.The anchor, made of one piece of sheet metal, is economical to manufacture in a multistage strip forming press. It is especially useful for securing articles to hollow partition walls.

Abstract: An elongate hollow rock structure and installation wherein the elongated shank of the bolt is hollow and has a series of outwardly bowed side or side portions that are capable of resilient deflection. Fin means are provided in sides or side portion, with the overall span of the fin means being greater than the bolt hole into which the bolt is to be impacted. The pin means are tapered so as to provide for ease of insertion of the bolt. Impaction of the bolt into a mine roof hole provides for a compression loading of the fins of the bolt shank such that these engage the aperture wall in a forced-compression state. Corrosion factors are limited to fin edge contact with the aperture wall of the bolt hole. Resilient sides' deformation at the core of the bolt shank is relied upon to compression load the fins for frictional contact with the aperture wall into which the bolt is implaced.

Abstract: An expansion dowel includes an axially elongated sleeve-shaped dowel body slit in the axial direction from the leading end. A spiral-shaped expansion body is located in the dowel body in the axially extending region of the slit. By axially displacing the expansion body toward the leading end of the dowel body it widens radially outwardly and in turn expands the axially slit region of the dowel body providing the required anchoring effect.

Abstract: An expansion anchor for anchoring in drill-holes, preferably in drill-holes having undercuts widening inwardly, comprises an expansion member having an expander cone supported at the bottom of the drill-hole, and an expansible sleeve driven onto the expander cone. The expansion member has an element for fastening or securing articles. The expansion member is punched out from sheet steel and the expander cone is rolled from a suitable flat blank. The gap provided at the outer surface of the expander cone is calibrated for closure.

Abstract: A tube-formed rockbolt is partly circular in its cross-section and opposite its circular portion (12) it has a deep depression (16-18). Its ends are sealed and its outer end has a hole (44, 45) or a fitting (24) through which the bolt can be supplied with high pressure water that expands the tube to anchor it in the borehole.

Abstract: A screw anchoring plug or bushing for use in predrilled mounting holes in elements of semihard materials such as chipboard, consisting of a sleeve made as a rolled up piece of metal sheet material provided with a number of slightly projecting barb-like tongue portions and cured to be resilient, whereby the tongue portions project as leaf springs. The sleeve is threaded for direct engagement with a standard screw, and when it is inserted in the mounting hole and the ends of the tongue portions are hereby caused to resiliently engage the wall of the hole, the sleeve will thereafter be moved axially outwardly when the screw is tightened, and the tongues will cut themselves into the hole wall and get spread to resist further retraction of the sleeve.

Abstract: A device for fastening an object against a wall as a plug-in mounting is described, which is provided with an externally threaded bolt, onto one end of which a nut can be threaded and on the other end of which, which is at least partially conical and the maximum diameter of which is equal at most to the diameter of the bolt, an expander element composed of two half-shell-like parts is displaceably held. The two half-shell-like expander parts are provided, on their two longitudianl edges which in the mounted state are located opposite one another, with at least two lobes each, which for mutually securing one another axially engage one another adjacently and are held on the conical end by positive adjacent engagement in the radial direction and are disposed on the expander element in such a manner that the expander element parts are transversely symmetrical or in the developed state are point-symmetrical.

Abstract: Disclosed are two embodiments (40, 50) of a self-locking prevailing torque fastener featuring a common base portion (2) having an aperture (4) therethrough for receiving a threaded member that is at least partially surrounded by means such as a warped helical edge (6) for engaging the threads of the threaded member. Fasteners (40, 50) are provided with a pair of spaced-apart resilient torque arms having respective sections (8) that respectively extend downwardly from opposite edge of base portion (2) to sections (10) that extend upwardly to sections (12) that extend through respective openings (14) in each to respective free-ends (16) that are adapted to press against opposite sides of the threaded member.

Abstract: A horseshoe shaped body formed of planar sheet metal is formed with a pair of legs joined at one end by an arcuate web. A portion of the web is bent perpendicularly to the legs, and each of said legs has a flange extending outwardly within the plane of the body at each of its free ends. A series of teeth along the inner edges thereof receive and mesh with the threads of the screw inserted therebetween.

Abstract: A plastic fastener for panels comprises in combination a main body of the shape of an angular pillar provided at the upper end thereof with a flange, elastic tongues formed one each on one of the two pairs of opposed side walls of the main body and extended from the lower side of the flange and slanted downwardly toward the interior of the main body, and fitting means formed one each on the other pair of side walls as bulged outwardly, with the aforementioned elastic tongues provided at the lower ends thereof with grips having threads incised therein. With this plastic fastener, union of a supporting panel and a supported panel is accomplished by inserting the main body into a hole bored in advance in the supporting panel until the flange thereof comes into tight contact with the supported panel and depressing a screw past the supported panel into the main body thereby causing the threads on the grips to come into fast engagement with the threads on the screw.

Abstract: A roof support pin for insertion into a roof bore having an opening comprising an elongate tube for insertion into the bore, the tube being compressed prior to insertion of the tube into the bore opening so that the tube expands to frictionally engage the bore a distance from the bore opening. In one embodiment, a roof support plate has a hole with a diameter smaller than the diameter of the bore. The plate hole compresses the diameter of the tube upon insertion of the tube into the bore through the plate hole. In another aspect, a plurality of rings longitudinally spaced axially on and retain the tube compressed prior to insertion of the tube through the plate hole into the bore. The rings slidably engage the tube for retention at the plate for allowing the tube to expand within the bore. In yet another embodiment, a spiral strip wraps and retains the tube compressed prior to insertion into the bore. The spiral strip is stripped from the tube as the tube is inserted through the plate hole.

Abstract: A fastener useful for securing articles on a hollow wall, made of a thin sheet of metal, shaped as to provide two spreadable pointed thin blades for easy insertion into a wall where after the blades are spread apart by the insertion of a screw to form an anchor resisting withdrawal.

Abstract: An expansion dowel assembly includes an expanding sleeve and a spacer sleeve with a deformable metal sleeve spacer member extending between them. At the outset, the spacer member has a non-circular cross section, however, during the expansion operation, the spacer sleeve telescopes into the spacer member and deforms it outwardly so that it assumes an approximately circular cross sectional shape.

Abstract: An expansion screw for being secured in a cavity is threaded at the outer end of its screw portion for co-action with a nut (2) and is provided with an expandable sleeve (10) about its opposite end. The sleeve has an inner profile coacting with an outer profile of the expansion screw for expanding the sleeve when the screw (1) is withdrawn from the sleeve. The outer profile of the screw portion (1) is formed by a plurality of coaxial cones (3-6) with intermediate cylindrical junction portions (7-10), all cones and junction portions being integral with the rest of the screw portion. The inner profile of the sleeve (10) is formed by thickened regions (12), projecting inwards from the inner surface of the sleeve and corresponding to the cylindrical junction portions, and by thinner regions (13) of the sleeve corresponding to the coaxial cones.