Abstract:
The invention relates to a screw (1), especially a concrete screw, for screwing into a borehole (20) with a borehole wall (25). Said screw comprises a body (2) having an insertion end (3), a screw down longitudinal direction (5) and a center longitudinal axis (4) and has a thread (7) configured as one-piece with the body (2). Said thread comprises a cutting thread (9) which extends from the insertion end (3) against the screw down longitudinal direction (5) and which has cutting thread flanks (12, 13) running in an essentially parallel manner in relation to one another, has cutting notches (17) which open in a radially outward manner, and a normal thread (11) which follows said cutting thread (9), whereby the normal thread (11) comprises an essentially triangular cross-section.
Abstract:
A fixing device comprises a bright zinc-plated steel shank (1) formed by cold forming with a head (2), the shank having formed thereon by thread-rolling a helical bore wall engagement configuration (6). This configuration comprises a pair of spaced apart helical ridges (7, 8) with a helical ridge (9) of larger elevation provided midway therebetween. The device readily self-taps when turned into a bore in a variety of materials. The device holds firmly in timer end grain and on continued turning of its head will perforate and embed in the timber, no amount of torquing causing the device to ream the bore when the device is penetrated into autoclaved aereated concrete.
Abstract:
The invention pertains to a screw produced by cold rolling, designed to be screwed into plastic material, and having a self tapping thread, the fillets (3) of which are formed, in a sectional view, like a knife blade. The fillet flank surface (6, 8) features an inward curve (5) in its central third and forms an outer thread flank angle ( alpha ) of approximately 30 (between the curve (5) and the crest of thread (27)) as well as an inner thread flank angle ( beta ) (between the curve (5) and the thread root (7)), while the inner thread flank angle ( beta ) in the central portion is substantially equal to or larger than a third of the outer thread flank angle ( alpha ). The invention also relates to a screw, the shank end (34) of which operates as a guide for screwing said screw into a bore (41), while the thread end (32) presents, on the one hand, an end area (36) having a cutting edge (58) for cutting its channel of screw and being oriented askew relative to the radial direction of the screw and, on the other hand, a base line (56) which extends the thread foot edge (60) between a thread flank (49) and the shank jacket (33) and runs in the spiral direction of the screw (32) according to an angle ( beta ) substantially deviating from 90 , while the cutting edge (48) extends into the crest (40) of thread.
Abstract:
The invention pertains to a screw produced by cold rolling, designed to be screwed into plastic material, and having a self tapping thread, the fillets of which are formed, in a sectional view, like a knife blade. The fillet flank surface features an inward curve in its central third and forms an outer thread flank angle of approximately 30 (between the curve and the crest of thread) as well as an inner thread flank angle (between the curve and the thread root), while the inner thread flank angle in the central portion is substantially equal to or larger than a third of the outer thread flank angle. The invention also relates to a screw, the shank jacket of which operates as a guide for screwing said screw into a bore, while the thread end presents, on the one hand, an end area having a cutting edge for cutting its channel of screw and being oriented askew relative to the radial direction of the screw and, on the other hand, a base line which extends the thread foot edge between a thread flank and the shank jacket and runs in the spiral direction of the screw according to an angle substantially deviating from 90 , while the cutting edge extends into the crest of thread.
Abstract:
A threaded fastener (1) is disclosed for anchoring into a substrate comprising a core portion (2) having at least one helical continuous thread provided along a substantial portion of the length of the core, in which the helical thread has a substantially V-shaped cross section defining two flanks (4a, 4b) which subtend an angle of between substantially 60 DEG and 90 DEG , and the thread has a helix angle of between approximately 20 DEG and 45 DEG . The crest of the thread may be flattened, and the fastener (1) is especially suited to anchoring to a masonry substrate.
Abstract:
Tube screws for penetrating materials such as wood, metal and plaster boards to provide an anchoring for a fixing and/or joining such materials is characterised in that at least along its length there are provided external and internal sharp-edged screw threads adapted to cut an elongate annular cavity in material through which the tube screw is rotated. Preferably the tube screws are provided with a profile at at least one of their ends adapted to cut material by a rotating action. Such a tube screw has ends (4,4) having thread starts (5,5).