US3605547A - Self-aligning screw anchor - Google Patents

Abstract

A SCREW ANCHOR, TO BE ENGAGED BY A BOLT TRAVERSING A WALL, COMPRISES A RIGID BAR ALONGSIDE WHICH A LANYARD IS ENTRAINED THROUGH A HOLE PREFORMED IN THE WALL OR PIERCED IN IT BY AN ENLARGED, POINTED HEAD OF THE BAR, THE LANYARD IS ATTACHED TO THE BAR IN THE VICINITY OF A THREADED TRANSVERSE BORE THEREOF WHICH ALIGNS ITSELF WITH THE PIERCED HOLE WHEN THE BAR IS PULLED FLAT AGAINST THE REMOTE WALL SURFACE AFTER ITS TRAILING END OR FOOT HAS CLEARED THE HOLE, MEANS BEING PROVIDED FOR SWINGING THE BAR OUT OF ALIGNMENT WITH THE LANYARD IN ORDER TO PREVENT ITS FOOT FROM BLOCKING THE PULLBACK.

Description

Sept. 20, 1971 o. 'r. MlLLE'i' 3,605,547

SELF-ALIGNING SCREW ANCHOR Filed April 10, 1969 3 Sheets-Sheet 1 Z; l00- -roo 11b kttomey David I. Milief INVENIOR.

Sept. 20, 1971' o. 1'. MILLET SELF-ALIGNING SCREW ANCHOR 3 Sheets-Sheet 2 Filed April 10. 1969 7 G. o m H 4 A f z 3 RUIN w/ in R1 4! h, 3 d 3 c W W a 11 n I d David I. Millet INVEN'IOR.

2 FIG. 9 BY pt. 20. 1911" D. T. MM. 3,605,547

SELF-ALIGNING SCREW ANCHOR Filed April 10. 1969 .3 Sheets-Sheet 5 77 F7 INVENTORI David I. Mil/9f [77a], BY

(Kurt g RpSS Attorney United States Patent 3,605,547 SELF-ALIGNING SCREW ANCHOR David I. Millet, 155 E. 4th St., New York, NY. 10009 Filed Apr. 10, 1969, Ser. No. 815,114 Int. Cl. F16b 37/04 US. Cl. 853S 2 Claims ABSTRACT OF THE DISCLOSURE A screw anchor, to be engaged by a bolt traversing a wall, comprises a rigid bar alongside which a lanyard is entrained through a hole preformed in the wall or pierced in it by an enlarged, pointed head of the bar; the lanyard is attached to the bar in the vicinity of a threaded transverse bore thereof which aligns itself with the pierced hole when the bar is pulled flat against the remote wall surface after its trailing end or foot has cleared the hole, means being provided for swinging the bar out of alignment with the lanyard in order to prevent its foot fromblocking the pullback.

My present invention relates to a screw anchor engageable by a threaded bolt which traverses a wall member in order to support a load thereon. Such screw anchors are used on panels, container Walls and other usually but not necessarily erect wall members of lath and plaster, plasterboard, fiberboard, sheet metal or the like having one inaccessible, remote side.

Conventional screw anchors of this type are designed as so-called toggle nuts, i.e. bars pivotally secured to small nuts engaged by bolts for joint passage through a hole in a wall member, or as internally threaded tubes with spreadable fingers (known in the trade as mollies) that can be deployed against the far side of the wall by a tightening of a mating belt which must then be removed and reinserted by way of a fixture or other load to be secured to the wall. The latter procedure is rather cumbersome and requires advance knowledge of the wall thickness for proper dimensioning of the tube, whereas the use of toggle nuts involves the penetration of the load by both the bolt and the bar since the bolt cannot be withdrawn in order to prevent irretrievable loss of the nut.

The general object of my present invention is to provide an improved screw anchor for the purpose set forth which is of simple design and easy to manufacture while avoiding the disadvantages set forth above.

More particularly, it is an object of this invention to provide a screw anchor which, unlike the conventional molly, can be used with a wide range of wall thicknesses and, in contradistinction to the known toggle nut, can be emplaced in the absence of the load which, subsequently, needs to be traversed only by the bolt so that its boltreceiving hole or eye may be of relatively small diameter.

Another object of my invention is to provide a screw anchor which, in addition to affording the aforestated advantages, can pierce its own mounting hole in the panel or other wall member to which it is to be affixed.

These objects are realized, pursuant to my present invention, by the provision of a rigid bar having a threaded bore extending transversely from a major face thereof, in combination with an elongate, preferably flexible element--hereinafter referred to as a lanyard-attached to that face in the immediate vicinity of the threaded bore and movable with reference to the bar. When designed for or foot clearing the pierced hole, the bar is swung out of alignment with the lanyard by positioning means on the bar designed to prevent its foot from blocking a reverse movement whereby, in response to a pull exerted upon the outwardly projecting trailing end of the lanyard, the said face of the bar comes to rest against the remote wall surface with its bore in alignment with the pierced hole. The enlarged head can be omitted along with the pointed edge, if the wall has a preformed hole wide enough to receive the bar with the lanyard next to it.

The positioning means serving to swing the bar may be constituted by a resilient hinge connecting the bar with the lanyard, in the simplest case through an extension of the elastic lanyard itself; it is, however, also possible to use one or more springs bearing upon the lanyard which in that case may be inherently inelastic. Alternatively, or in addition, the bar may have a weighted portion so as to be top-heavy when emerging from the pierced hole, thus tilting about a substantially horizontal hinge axis with elevation of the threaded bore above that axis to confront the hole. A further possibility resides in the provision of second elongate element or lanyard extending alongside the first-mentioned one during insertion, the two elements being attached to the bar on opposite sides of the threaded bore so that by their manipulation the bar can be properly oriented.

Besides helping position the bar behind the wall as an anchor nut for a screw or bolt, the lanyard according to the invention may also serve two further functions, namely (a) that of firmly holding the bar onto the remote wall surface during insertion of the bolt and (b) that of securing the bar against rotation with the bolt during the screwing of the latter into the threaded bore. The first function involves the fastening of the projecting forward extremity of the lanyard to the front surface of the wall in a taut state, e.g. with the aid of an adhesive coating or a tack, wherebyparticularly if this element consists of resilient material-the :bar is held in close contact with the rear wall surface while the bolt, traversing the fixture or other load to be supported thereby, is introduced into the hole alongside or through the flat or tubular lanyard. The second purpose may be accomplished if the lanyard itself lacks the necessary torsibility, by the provision of a stiffening strip adjacent the lanyard and/or the presence of a forwardly projecting boss on the wall-engaging face of the bar, with the lanyard (reinforced or not) or the boss fitting sufliciently snugly in the pierced hole to resist rotation about the bolt axis. The enlarged head of the bar, when forming a transverse shoulder beyond the point of attachment of the lanyard, also helps resist rotation since its wedge-shaped profile at that shoulder will tend to bite into the yieldable wall material at a certain distance from the axis of the bore and the bolt. The tendency of the bar to rotate with the bolt can be reduced, however, in a manner known per se by having the threads of the bolt fit only loosely into those of the bar in an initial stage of insertion, whereupon the bar may be drawn forward by the bolt to increase its frictional contact with the wall as the bolt is screwed home.

The above and other features of my invention Will be described in greater detail hereinafter with reference to the accompanying drawing in which:

FIG. 1 is an isometric view of an embodiment of my invention;

FIGS. 2-5 are side-elevational views of the same embodiment, showing consecutive steps in the emplacement of my improved screw anchor;

FIGS. 6 and 7 are side views of two modifications of the device of FIGS. l-S;

FIG. 8 is a vertical section of a screw anchor reprepresenting a further embodiment;

FIG. 9 is a side view, partly in section, of a modification of the device of FIG. 8;

FIG. 10 is a view similar to FIG. 8, illustrating another modification;

FIG. 11 is an end view of the device of FIG. 10, taken in the direction of arrow XI thereof;

FIG. 12 is a side View showing still another screw anchor according to my invention partly driven through a wall;

FIG. 13 is a similar view showing the embodiment of FIG. 12 fully emplaced;

FIG. 14 is a front-elevational view of the device of FIG. 13;

FIG. 15 is a view similar to FIG. 10 taken on the line XV-XV of FIG. 13;

FIG. 16 is an isometric view of yet a further embodiment of my invention;

FIG. 17 is a side view showing the embodiment of FIG. 16 partly driven through a wall; and

FIGS. 18 and 19 are views similar to FIG. 7, illustrating two further modifications.

In FIGS. 1-5 I have shown a screw anchor 10- according to my invention, comprising a rigid bar 11 (e.g. of metal) which resembles a conventional toggle nut in being movably supported on a carrier 12 and provided with a threaded bore 13 designed to receive a bolt 14 (FIG. after being driven through a wall 100. Carrier 12,. referred to hereinafter as a lanyard, is a resilient strap or thong (e.g. of rubber) which, when unstressed, is generally L- shaped, with the shorter leg 12:: of the L cemented or otherwise secured to the bar 11 and the longer leg 12c extending generally perpendicularly therefrom, the two legs being interconnected at a bend 12b in the immediate vicinity of bore 13. Bar 11 terminates at one end in a pointed head 11aforming a projecting edge 11c which overhangs the adjoining leg 12a of the lanyard 12. Bend 12b acts as a resiliently biased hinge which, while urging the leg 120 into its transverse position, nevertheless allows the same to be flattened against the adjoining face of bar 11 as a coplanar extension of leg 12a.

FIG. 2 illustrates the mounting of the device on a wall by flattening the lanyard 12 against the bar 11 and driving the assembly through the wall 100, with the pointed head Ella leading, as indicated by an arrow A. For this purpose, the flat trailing end 111) .of the bar 11 may be struck by a hammer and then pushed completely through the resulting hole 101 in wall 100 with the aid of a screwdriver or other convenient tool. As soon as the end lllb clears the hole 101, lanyard 12 tends to resume its remembered shape whereupon bar 11 swings into an at least partly erect position as illustrated in FIG. 3, preferably through an angle of 90 or greater. If this angle is obtuse, as shown, a forward pull on the lanyard 12 (arrow B, FIG. 4) brings the head 11a of the bar into contact with the rear surface of wall 100 whereupon further traction will drag this head upwardly along that surface, without any risk of jamming, until the position of FIG. 5 is reached in which the bar 11 is drawn flat against the wall 100 with the lanyard held stretched along the bottom of hole 101 to align the bore 13 with that hole for traversal by the bolt 14. In this position the beveled edge 11c of bar 11, projecting slightly beyond the thickness of lanyard 12, may bite into the rear surface of Wall 100 to help secure the bar '11 against rotation when the bolt 14 is screwed home. Such rotation of the bar is also resisted by the lanyard 12 which may be held taut by gluing or otherwise fastening its free end to the front of wall 100 as illustrated at in FIG. 5.

If the hole 101 is to be plugged for purposes of re plastering, or if the screw anchor 10 is to be replaced by another one of different thread diameter, the lanyard 12 may be detached from the wall whereupon the device will simply drop into the space therebeyond.

In FIG. 6 I have shown a modified screw anchor 20 whose bar 21 is generally similar to that of the preceding embodiment but whose lanyard 22 has a remembered shape of a J or U, consisting of a fixed leg 22a, an intermediate link 22b adjacent the threaded bore 23 and a free leg 22c parallel to leg 22a in the unstressed state. The distance a" between legs 22a and 220 corresponds here to the thickness of the wall on which the device is to be mounted; this dispenses with the need for fastening the projecting leg of the lanyard to the front surface of the wall.

The screw anchor 30 of FIG. 7 differs from those of the preceding figures by having a normally arcuate strap 32 secured to its bar 31, by mechanical clamping and/ or cementing, at a recess 31d in the immediate vicinity of the bore 33 thereof. With the lanyard 32 again resting on the bottom of the pierced hole 101, the bar 31 tends to assume the swung-out position illustrated in FIG. 7 from which it can be pulled fiat against the hole in the manner illustrated in FIG. 5, followed by a fastening of the lanyard as described above. Since in this case the biasing force stored in the lanyard to deflect the bar is distributed over the entire length of the lanyard, the latter can be made of a relatively stiff material such as spring steel.

In FIG. 8 I have shown a screw anchor 40 whose bar 41, generally similar to the bars of the preceding embodiments, is anchored to it by a lanyard 42 in the form of a tube of rubber or other resilient material which is adhesively bonded to the bar 41 around its threaded bore 43, the outer diameter of the tube 42 being slightly less than the maximum width of the head 41a of bar 41 in order that the hole 101 pierced by this head may accommodate a reinforcing strip 45 of less readily deformable material, e.g. of soft metal such as copper or brass, extending alongside the tube while being adhesively bonded thereto. After the bar 41 has been positioned fiat against the far side of wall 100 in the manner previously described, tube 42 is partly severed at 42d in the plane of the near face of the wall, so as to form two sections 42a, 42c interconnected at a bend 42b by the flexible strip 45 which may be supplemented by a residue of intact tube material. Tube section 420 is then secured to the front surface of the wall while exposing the bore 43. The operation is similar to that previously described, except that the bolt to be threaded into bore 43 also traverses the tube section 42a. Reinforcing strip 45 could also be made of elastic material (eg. spring steel) to supplement the restoring action of tube 42.

In FIG. 9 I have shown a modified screw anchor 40 whose bar 41, designed for insertion into a preformed hole 101' of a wall 100', is a fiat prismatic body lacking the enlarged head of the preceding embodiments. Tube 42, aligned with bore 43', is similar to tube 42 of FIG. 8.

The screw anchor 50 illustrated in FIGS. 10 and 11 has its bar 51 formed with a rearwardly divergent gap 51d closely spaced from the bore 53, this gap receiving an end of a resilient tube 52 which is cut away at 52d so as to form a hinge 52b immediately adjacent the wallcontacting face of the bar. The end of tube 52 may be molded directly into the gap 51d of bar 51. The forwardly projecting extremity of the tubular lanyard 52 is split into two halves 52a, 520 which, when the assembly is properly positioned, are held against the front surface of wall 100 by an annular washer 56 with an adhesive coating engaging the wall. The center hole 56a of this washer gives access to the bore 53 of bar 51, the engaging bolt again passing through a section of the tubular lanyard.

The tubes 42 and S2 of FIGS. 8-1l could also be made of a synthetic elastomer such as polyethylene or polypropylene, and in the most common case may have diameters and wall thicknesses similar to those of an artificial drinking straw.

In FIGS. 12-1S I have shown a screw anchor 60 having means for positively preventing any rotation of its bar 61 with reference to the supporting wall 100. The

head 61a of this bar is wedge-shaped and adjoins, without overhang, the body of the bar which converges toward the opposite end 61b; a boss 61e, rising from the initially upwardly positioned face of the bar, traverses the bore 63 and is set sufiiciently far back from the head 61a to clear the hole 101 pierced by this head in the wall 100 as seen in FIG. 12. A lanyard 62, here shown to be of the strap type similar to that illustrated in FIGS. 1-5, is secured to the bar in the aforedescribed manner at a recess 61d adjacent boss 612. The noncircular profile of boss 61e, here shown to be rectangular, is slightly smaller than that of the head 61a at its widest point so that this boss, together with lanyard 62, fits closely in the hole 101 as best seen in FIG. 15, thereby holding the bar 61 against rotary entrainment by the mating bolt. To facilitate the insertion of boss 61e into the hole 101 upon a forward pull on the lanyard 12, the lateral faces of the bar 61 may also be given a slight draft as seen in FIG. 14; the width of lanyard 62 may then somewhat exceed that of bass 612, corresponding to the maximum width of head 61a.

In this embodiment the lanyard 62 follows the bar 61 through the wall in the wake not only of its head 61a but also of boss 61e, coming to rest on the bottom of hole 101 only after the bar 61 has been pushed fully through the wall. The lanyard, in this case, must be stiffer than in the preceding embodiments to overcome the top-heavy weight distribution of bar 61a.

In FIGS. 16 and 17 I have shown a screw anchor 70 whose bar 71 is attached to two lanyards 72, 72" on opposite sides of its bore 73. Lanyard 72 is secured to the bar 71 adjacent the transverse edge 17c of head 71a whereas lanyard 72" engages the bar just beyond a step 61 of a height substantially corresponding to the thickness of that lanyard, whereby the two thongs come to lie one atop the other on the bar 71 in the shelter of is head 71:: when the bar is driven through a wall 100 as shown in FIG. 17. Bar 71 has a pair of laterally spaced lugs 71g which bracket the reduced extremities 72a 72a" of the lanyards when the same are folded against the bar in the insertion position of FIG. 17, these reduced extremities being subsequently bent in opposite directions (as illustrated in FIG. 16) to immobilize the bar on the wall, as previously described, while giving access to the bore 73. For this purpose a washer 56 (FIGS. and 11) may be used to hold the ends 72a and 72a" against the front surface of the wall 100.

With the embodiment of FIGS. 16 and 17 it is not essential that the lanyards be made of elastic material since the erection of the bar after the traverse of the wall can be controlled by relative manipulation of the two extremities 72a and 72a".

FIG. 18 shows a screw anchor 80 whose bar 81, similar to that of FIGS. 1-5, is hingedly attached at 81d to a lanyard 82 which in this instance may be a rigid rod or strip. A spring 87 tends to swing the element 82 into a position substantially transverse to bar 81 whereby, upon penetration of the wall 100, the head 81a of the bar pivots upwardly (arrow C) so that the foot of the bar recedes from wall 100 into a nonblocking position. Spring 87 is, of course, representative of any suitable biasing means tending to bring about such clockwise motion of bar 81 with reference to lanyard 82.

In FIG. 19 I have shown a further embodiment in the form of a screw anchor 90 whose bar 91 has a top-heavy head 91a, the lanyard 92 being hingedly secured to the bar at a location 91d between the head and the bore 93. In this case, too, the lanyard 92 may be a rod or strip of substantially conresilient material. As the bar 91 clears the hole 101, it tilts counterclockwise (arrow 1)) about the hinge 91d under its own weight so that its tail end 91b again assumes a nonblocking attitude.

It will be understood that compatible features of different embodiments (e.g. the boss 61e of FIGS. 12-15 and the spring 87 of FIG. 18) may be combined and that the precise shapes and specific materials herein disclosed are not crtical.

I claim:

1. A screw anchor comprising a rigid bar having a major face provided with a threaded transverse bore located between the ends of the bar, one of said ends being an enlarged head with a pointed forward edge and with a rear edge parallel to said face at a location of maximum thickness of said bar ahead of said bore, and a resilient tube secured to said bar at said face at a location of reduced thickness in the immediate vicinity of said bore and adapted to lie alongside said face in the shelter of said transverse rear edge upon passage of said bar through a hole in a wall pierced by said head, said tube forming with said bar a junction so biased as to swing said bar out of alignment with said tube upon the trailing end of said bar clearing said hole whereby said face comes to lie against a rear surface of said wall, with said bore confronting said hole, upon a pull on a projecting extremity of said tube trailing said bar, said tube having an inner diameter greater than that of said bore and being provided with a cut-away portion adjacent said face for giving clearance to a bolt traversing said hole within said tube and engaging the threads of said bore.

2. A screw anchor as defined in claim 1 wherein the front extremity of said tube is longitudinally split into two halves attachable to the front surface of said wall on opposite sides of said hole.

References Cited V UNITED STATES PATENTS 991,426 5/1911 Clements -3K 2,398,220 4/ 1946 Gelpscke 853K 2,919,089 12/1959 Durham 85-3 3,211,042 10/1965 Fischer 853 EDWARD C. ALLEN, Primary Examiner

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