TUBE SCREWS AND METHODS OF PENETRATING MATERIALS USING TUBE SCREWS

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).

Description: TUBESCREWSANDMETHODSOFPENETRATINGMATERIALS USINGTUBESCREWS This invention relates to ttibe screws and methods of penetrating materials, e.g. wooden or metal components or components of softer materials e.g. plaster boards, using such tube screws e.g. to form an anchor for a hook or for connecting tvo or more components, and particularly relates to penetrating such materials without the necess¬ ity of first forming a hole in such materials for the reception of the tube screws. Proposals have previαtisly been made for joining wood to other solid components using tubular, members. Thus British Patent specification 5^1 3^5/filed by George Ernest Osniond on May 21st 19^-1 describes a method of joining using a screw or hollow connector of tubular form. The jointing member when in place can be used as a conduit for electric leads, or as a bush i.e. by the provision of an appropriate internal thread. The tubular member is used in conjunction with an operating tool whereby the screw is driven into the solid substance to be joined. Such a tubular member may be grooved to permit a simple spindle operating tool to be used for driving the member into plain or screw-threaded holes into the materials to be joined, or the operating member may itself be threaded on its internal surface for the recep¬ tion of a corresponding threaded portion of the spindle operating tool. Such a tubular joining member may be made by corrugating thin sheet metal tubes, the resulting cavity wall accommodating a threaded driving tool or for use as a bush. It is an essential feature of such tubular members that they are inserted into unthreaded holes in the material to be joined, a notched leading edge being provided whereby the thread is self-tapping. It is also an essential feature that the bore cavity serves as a throat for the resulting cuttings. OMPI ^ flNAT British Patent specification 957 8 2 filed by Eric Arnold Stromberg on June 22nd 19^2 describes a tubular fastening member for being driven into end- grained wood in which the leading portion has a sharp edge and the plain tubular portion leading away from the sharp edge develops a helically extending groove whereby the fastening member can be driven into and withdrawn from a wooden support in the manner of a screw. In the embodiments illustrated the trailing edge is flared, so that it may be splayed out by a fixing to secure an object to the wood into which the fastening member is driven, or so that it may contain a slot to receive a screw driver. Such a device is primarily intended for driving into end-grained wood, and when joining other objects to such wood, the securing of such other objects to ' the wood is achieved by the splayed configuration of the trailing end. To engage the helically-extending grooves the device must- irst be dsiven e.g. by hammer blows, into the wood. Furthermore any helically-extending grooves which may be provided on the body of the tube do not provide a sharp cutting edge so that the fastening member may only be screwed into the wood with difficulty. The present invention is directed to a tube screw which in use may readily be inserted into materials without the provision of preformed holes in such materials and which relies for its holding effect solely on the combined effect of sharp edges threads on the internal and external surfaces o he tube screw, engaging the material into which it is rotatably inserted and forming, by cutting as it is rotated into the material, a threaded elongate annular cavity therein. OM **N A Thus in its general form the invention provides an open-ended tttbe screw having along at least part of its length external and internal sharp-edged screw threads. Preferably the tube screw has a constant diameter. The invention also provides a method of pene¬ trating a material, comprising presenting the said open- ended tube screw to a material and rotating -same whereby it progressively cuts a threaded elongate annular cavity therethrough and optionally thereafter progressively engages by continued rotation a second material to cut a threaded elongate annular, cavity at least partly there¬ through. Thus the method may be used to provide in a single material for the. reception e.g. of a hook, or two or more materials. The sharp edged screw threads on the external and. internal surfaces of the tube screw's of, and for use in the method of, the invention may have a variety of profiles as hereinafter described. The tube screws may conveniently be threaded along their entire length and thus be of substantially constant diameter. They may be provided with a profile at their ends whereby a second tube element may be offered up to a first tube screw already inserted in material to be ' connected, and by rotation further rotate the said first tube element. By this means tube elements may be used which have a length shorter than that required to reach a second material to be connected. The tube screws of, and for use in the method of, the invention may be used" in association with a driver for exerting a rotation thereto when applied to an end of the tube screw. Thus such a driver may have a pro- filed end portion adapted to engage a corresponding profile on an end of a tube screw. In a particular embodiment the tube screw is used in association with a driver having an internally- and/or externally threaded hollow end of thread profile corresponding to the threads on the tube screw. In a particular embodiment of the tube screws of, and for use in the method of, th ' e invention, an assembly is provided of two tube screws disposed parallel to each other, each side of a tongue element preferably having a sharpened .leading edge, and rotatably connected to opposite edges of said tongue element. Thus when the tube screws are simultaneously rotated into .a material to be connected, the said tongue element is carried with the said tube screws into the material, to provide an auxiliary connecting element. The tube screws of, and for use in the method of, the invention may be made of any suitable material capable of being formed into sharp-edged screw threads e.g. by machining. Thus they may be formed of- metal, particularly steel or aluminium alloy, or a suitable plastics material e.g. ABS plastics, nylon or polyester plastics material. They may be of rigid construction but a particular embodi¬ ment of the invention uses a tube screw which is flexible along its longitudinal axis whereby it may be inserted into materials to be connected using flexible driving means. The invention is hereinafter described in more detail, with reference to the accompanying drawings, of which Figure 1 is a longitudinal section of tube screw according to the invention; Figure 2 is a perspective view of a tube screw provided with profiled ends consisting of thread starts; Figures 3(a) to 3(j) are examples of profiles of the threads present on the external and internal surfaces of the tube screw; Figure is a side view of a screw in which the screw threads are interrupted threads; . Figures 5( a ) to 5 ( g) are representational examples of alternative profiles which may be applied to 5 the ends of the tube screw; Figure 6 is a longitudinal sectional representa¬ tion of two pieces of wood joined together by a tube screw according to the method of the inventi'on and showing a driving tool in position at the trailing end of the 10 ' tube screw; Figure 7 is a longitudinal sectional representa¬ tion of the joint of Figure k showing a following tube screw in place within a guide therefor; Figure 8 is a longitudinal second representation 15 of two pieces of material joined by a tube screw, the open end of which is provided with a stopper; ,, Figure 9 is a side view of a tube screw when in position which is provided with an oversize stopper the end of the tube screw becomes splayed; and 20 Figure 10 is a schematic representation of an assembly according to the invention of two tube screws each rotatably mounted on a side of a control blade element. Referring to the drawings, Figure 1 shows one 25 embodiment of a tube screw 1 according to the invention made of thin-walled material e.g. metal or plastics material, having along its length an external sharp-edged screw thread 2 and an internal sharp-edged screw thread 3. In the embodiment illustrated the internal and 0 external threads are in phase giving a corrugated appearance. If desired however they may be out of phase with each other. Figure 2 shows another embodiment wherein the ends k , k of the tube thread are profiled by the provis- 5 ion of starts 5 presenting a notched appearance. Such notched profiles may serve for instance to engage OMPΪ ? AT initially the material to which the. tube screw is presented, and/or to provide engagement with a correspon¬ dingly profiled driving tool, and/or to engage the similarly profiled end of a longitudinally contiguous tube screw when a plurality of tube screws are rotatably driven into material. The profiles of the screw threads may take a variety of forms as shown in Figures 3(a) to.3(j), the essential feature being that the threads are sharp-edged. Figures 3(a) to 3 (h.) show profiles which are flat-faced, and Figure 3(j) shows a profile which has curved faces. The profile of Figure 3(f) may be obtained by subjecting a plain tube to a series of helically-disposed perfora¬ tions, and then to apply to the thus-perforated tube a band e.g. a steel band having one edge sharpened and the other edge profiled to provide sharpened tongues along its length spaced apart from each other so as to fit into adjacent perforations in the tube when the strip is wound helically around the perforated tube, the edges of said tongues being sharpened. By this means a tube is provided which has on one surface a sharp-edged continuous thread, and on the other surface a sharp-edged discontinu¬ ous thread. The profiled band may be spirally wound on or in the tube whereby the continuous thread is either on the outside or the inside surface- of the tube. One or both screw threads on the tube screw according to the invention may be continuous screw threads, or they may be discontinuous, e.g. as hereinbefore des¬ cribed in relation to Figure 3(f) or as shown in Figure k , wherein a series of stamping operations on the tube material produces a series of flanges, generally in a spiral configuration. Such flanges may extend inwardly and outwardly of the tube body. If desired, one or more flutes may be provided longitudinally of the threads on the tube screw so as to " provide a channel for debris generated by the tube _ UMPI * W - IP ^ AT screw being rotatably driven into material. As hereinbefore described and illustrated for example in Figure 2, the ends of the tube screw may be profiled. A variety of end profiles may be used, examples of which are illustrated in Figures 5(a) to 5 ( g) • Such profiles may be adapted so that the tube screw may be turned in either direction by a correspondingly pro¬ filed driving tool e.g. as shown in Figures 5"(a) and 5(ϊ>) ». or may be adapted to be released when the direction of rotation of the driving tool is reversed. It is essential that such end profiles are adapted to cut material by a rotating action. Figure 6 illustrates a final stage in the method of penetration of the invention when the tube screw has been rotatably driven through a first wood piece 2 into a second wood piece 3 by a hollow threaded driving head k mounted on a support which may be rotated either manually or be power driven, the two wood pieces thereby being ■ joined. Figure 7 illustrates a method of joining- in which after a first tube screw 1 has been inserted into the wood portion as described and illustrated in Figure 6, a following and similar tube screw 2 is presented to the trailing edge of the tube screw, preferably through guide means 3 > and rotated so as further to displace the first tube screw 1 deeper into the materials to be joined. As hereinbefore described, the ends of the tube screws may be profiled to intercalate with each other, to effect rotation of the leading tube screw by the rotating following tube screw. After the tube screw has been inserted into the material, a hook, eye or other fixing may be inserted into the end portion which is substantially flush with the sur¬ face of the material into which it is contained or onto a protruding part. If desired a sealing plug may be in¬ serted. Thus Figure 8 shows a plug 6 having a hollow threaded portion engaged in the sunken end of the screw plug. If desired, the shown plug 6 may be in fact a further tube screw according to the invention having an external diameter corresponding to the internal diameter of the tube screw in situ, but provided at its trailing edge with a hook, eye or other fixing. If desired the plug 7 having an oversized hollow threaded portion may be used to effect splaying as shown in Figure 9 at 8. As hereinbefore set forth, instead of the plug a hook, eye or other functional fixing may be - inserted. As shown in Figure » if the trailing (or for- ward) end of the tube screw stands proud of material into which it is inserted, then the insertion of a plug or the like having an outwardly chamfered head as shown results in a splaying out of the free end of the tube screw, thus enhancing its* securing effect. A particularly interesting use of the tube screws of the invention lies in providing anchoring means in plaster board or similar clad materials having a relative¬ ly soft or friable core. Thus the tube screw is rotatably driven through the clad material, at least one of the ends standing proud of a cladding into which may be screwed a hook, eye or other functional device. Preferably the other end also stands proud of the remote cladding, and a bolt of other functional device may be screwed therein, or a segmental end may be turned back to provide an anchoring. In non-accessable voids, such turning back may be achieved by the use of a retractable butterfly device in known manner. Figure 10 shows an assembly according to the invention,, whereby two tube screws 9 and 10 are each rotatably attached by rings to a side of a central blade element 13 preferably having a sharpened leading edge Ik . " When the two tube threads are simultaneously rotated so as to enter material as hereinbefore described, the central portion 13 also enters the material, thus forming a reinforcing element or join therein to join two laterally disposed materials. OM Ar IP 2 NA

Claims: CLAIMS 1. A tube screw 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. 2. A tube screw according to Claim 1, characterised in that the said internal and external • screw, threads extend along the whole length of the tube screw. 3. A tube screw according to Claim 1 or Claim 2, characterised in that the said tube screw has a constant diameter, along its entire length. h . A tube screw according to Claim 1, characterised in that the said tube screws are provided with a profile at at least one of their ends adapted to cut material by a rotating action. 5 * A tube screw according to Claim k , wherein the said profile is provided by thread starts. 6. A tube screw according to any of Claims 1 to 5 » in association with a driver for exerting a rotation thereto when applied to an end of said tube screw. 7. A tube screw and driver according to Claim 6, wherein the said driver has a profiled end portion adapted to engage a corresponding profile on an end portion of the said tube screw. 8. A tube screw and driver according to Claim 6, wherein th.e said driver has a hollow end internally and/or externally threaded of profile corresponding to the threads of the said tube screw. 9. A tube screw according to any of Claims 1 to 8, which is made of metal or plastics material. 10. A tube screw according to Claim 9 » which is flexible along a longitudinal axis. 11. An assembly comprising two tube- screws according to any of Claims 1 to 10, rotatably mounted one on each side of a tongue element. 12. A method of penetrating a material with a tube screw, comprising presenting a tube screw according to any of Claims 1 to 10 to a material and rotating the tube screw whereby it progressively cuts a threaded elongate annular cavity therethrough. 13. A method according to Claim 12, wherein the tube screw is further rotated whereby it thereafter progressive¬ ly rotates through a further material whereby the two materials become connected. 14. A method according to Claim 12 or Claim 13 , wherein a further tube screw is applied to the trailing end of the screw already in the material, and rotated whereby both tube screws progressively enter the material. 15. A method according to any of 'Claims 12 to lk , wllerein a plug, hook, eye or other functional device having a hollow threaded portion is rotatably inserted into an end of a tube screw in the material, to provide a fixing. 16. A method according to Claim 15, wherein said plug, hook, eye or other functional device is provided ■ with an outwardly chamfered head whereby the said end of the tube screw standing proud of material in which it is inserted, is splayed out.

Inventors: STEENGRACHT MOYLAND J
Applicants: STEENGRACHT MOYLAND J
Application year: 1981
Main classification: F16B37
IPC codes: F16B5, F16B25, F16B37