US3136202A

US3136202A - Sheet metal expansion anchor having eccentric inturned edge

Info

Publication number: US3136202A
Application number: US199871A
Authority: US
Inventors: Arthur C Wagner
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-06-04
Filing date: 1962-06-04
Publication date: 1964-06-09
Anticipated expiration: 1981-06-09

Description

June 9, 1964 A. c. WAGNER 3,136,202

SHEET METAL EXPANSION ANCHOR HAVING ECCENTRIC INTURNED EDGE Filed June 4, 1962 2 Sheets-Sheet 1 Arz /zur C. Wagner ATT(')RNEY June 9, 1964 c, WAGNER 3,136,202

SHEET METAL EXPANSION ANCHOR HAVING ECCENTRIC INTURNED EDGE Filed June 4, 1962 2 Sheets-Sheet 2 INVENTOR ATTORNEY United States Patent 3,136,202 SHEET METAL EXPANSION ANCHOR HAVING ECCENTRIC INTURNED EDGE Arthur C. Wagner, 340 N. 7th St, Lebanon, Pa. Filed June 4, 1962, Ser. No. 199,871 3 Claims. (Cl. 85-24) This invention relates to anchors for fastenings such as screws and bolts, and more particularly to expansion anchors and to an apparatus for making expansion anchors. This application is a continuation-in-part of my prior application Serial No. 682,652, filed September 9, 1957, now Patent No. 3,038,521.

Expansion anchors are widely used for securing screws and bolts in concrete, stone, tile, cement block and the like and for more securely anchoring screw fastenings in worn screw holes in wooden support members. While 'there are many typesof preformed expansion anchors available on the market, the mechanic or other person requiring the use of such anchors must keep a large variety of sizes of anchors on hand to meet the requirements of the different sizes of screws and bolts which he may use.

Accordingly, it is an object of this invention to provide an apparatus for making expansion anchors or liners on the job as the need arises, and to provide an improved expansion anchor made by this apparatus.

It is a further object of this invention to provide an inexpensive apparatus for making expansion anchors Which can be retailed at a very nominal price and in which a single apparatus is capable of making a Wide variety of sizes ofexpansion anchors.

It is a still further object of this invention to provide an apparatus for making expansion anchors which per- 'mits the anchors to be made at considerably less expense than the cost of preformed anchors.

Itis another object of this invention to provide an expansion anchor made of soft metal and including a laterally inturned innermost edge portion which can be angularly adjusted to adjust the effectiveinternal diameter of the anchor member relative to the fastening mem- Q- ber received by the anchor.

It is another object of this invention to provide an expansion anchor made of soft metal and including a laterally inturned innermost edge portion which is pivotally movable about an axis which is eccentric or offset -with respect to the longitudinal axis of the anchor member to permit the screw fastener or the like being inserted in the anchor member to cam the inturned edge portion either clockwise or counterclockwise, depending upon the direction of eccentricity of the inturned edge,

to thereby permit selective control of the internal diameter of the anchor member. I

It is still another object of this invention to provide a method of winding expansion anchors in which the anchor member is wound in such manner as to have 1 an innermost inturned edge portion which is eccentrically located with respect to the longitudinal axis of the anchor member.

It is still another object of this invention to provide an expansion anchor formed from a metal blank which is shaped in such manner as to provide less thickness of material at the outer end of the formed anchor member to thereby facilitate the insertion of the fastener into the anchor member.

3,136,202 Patented June 9, 1964 "Ice .cludes a framework which supports a mandrel about which the blank is rolled or spirally wound to form the anchor. The framework also supports a guide roller adjacent the mandrel. The mandrel is not fastened to the frame, but is slidably supported in bearings on the frame from Which it may be easily withdrawn to permit removal of the rolled expansion anchor. The supporting framework is provided With several pairs of bearing supports on either side of the guide roller for interchangeably receiving mandrels of different diameters for rolling expansion anchors of different internal diameters.

Due to the provision of a slot in the forming mandrel which receives the innermost edge of the blank during the winding process, the finished anchor includes an innermost edge portion which extends laterally inwardly from the periphery of the innermost spiral turn of the anchor. Since the blank is made of soft metal this edge portion can be easily angularly bent about its ment of the anchor to compensate for either tightness or looseness of the anchor relative to the particular fastener member received by the anchor, and also to permit adjustment of the tightness of the anchor with respect to the hole in which the anchor is received.

Furthermore, the innermost edge portion of the finished anchor is eccentrically located in offset relation to the longitudinal axis of the anchor member, due to the fact that the slot in the forming mandrel is located in offset or eccentric relation to the longitudinal axis of the mandrel. By reversing the mandrel in the supporting framework in which it is located, but still rotating the mandrel in the same direction as before with respect to the same point of reference as before, the innermost edge portion of the formed anchor may be caused to lie either to the right or to the left of the longitudinal axis of the formed anchor. By offsetting the inturned edge away from the longitudinal axis of the anchor, the

fastener member or screw can enter the anchor freely -either in a clockwise or -a counterclockwise direction with respect to its pivotal connection of the spiral strip,

depending on which side of the longitudinal axis of the 55 the mandrel in such manner as to selectively cause the anchor the inturned edge is offset. Thus, by positioning inturned edge to be offset on a desired side of the longitudinal axis of the anchor, the inturned edge can either be bent by the incoming screw-fastener in a direction in which the inturned edge forms a continuous extension of the same spiral turn to which it is attached, or alternatively in a direction in which the inturned edge lies in doubled-over relation to the spiral turn to which it is attached, thus permitting control of the effective diameter of the anchor and further permitting adjustment ing. the overlapped ends together, as by riveting.

of the tightness of the anchor relative to the hole in which the anchor is positioned.

In order to facilitate the insertion of tie screw or bolt in the anchor member, the blank of soft metal from which the anchor member is formed is cut away at one corner thereof in the portion of the blank which forms the innermost turn or turns of the anchor and at the end of the blank which forms the mouth or entrance to the finished anchor. This cutting away of the blank reduces the thickness of the material at the end of the anchor into which the fastener is inserted and thereby facilitates the insertion of the fastener into the anchor.

Further objects and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of the anchor rolling apparatus being used to roll an expansion anchor from a blank of soft metal;

FIG. 2 is a top plan view, partially broken away, of the apparatus of FIG. 1;

FIG. 3 is a view in longitudinal section taken along line 3-3 of FIG. 1;

FIG. 4 is a perspective view of a mandrel of smaller diameter which may be used on the apparatus of FIG. 1; 7

FIG. 5 is a perspective view of a metal blank from which the expansion anchor is rolled;

FTG. 6 is a perspective view of an expansion anchor which has been rolled on the apparatus of the invention;

FIG. 7 is a View of a modified and preferred form of blank having a corner portion cut away;

FIG. 8 is an end view of a formed anchor member illustrating several positions into which the innermost edge portion or sizin strip may be adjusted;

PEG. 9 is a fragmentary view in vertical section, illustrating the reduced wall thickness of the anchor at the end formed from the cut portion of the blank;

FIG. 10 is a view of the device for winding an expansion anchor with the expansion anchor blank in position and with the mandrel inserted from the left-hand side of the framework with respect to the view shown in FIG. 10 to cause the offset slot of the mandrel to lie in a position which causes the inturned edge of the formed anchor member to lie to the left of the longitudinal axis of the formed anchor when viewed from the outer or head end of the formed anchor;

MG. 11 is a view in section showing the anchor member wound with the mandrel positioned as shown in FIG. 10, and illustrating the location of the inturned edge to the left of the longitudinal axes of the mandrel and of the anchor;

FiG. 12 is a view similar to FIG. 10 showing the blank positioned in the winding device and with the mandrel reversed from its position shown in FIG. 10 and inserted from the right-hand side of the framework; and

FIG. 13 shows the anchor member wound on the mandrel positioned as in FIG. 12 and illustrating the position of the inturned edge of the anchor to the right of.

the longitudinal axes of the mandrel and of the anchor member. 1

Referring now to the drawing, the device for rolling expansion anchors is generally indicated at l0 and includes a metal framework 11 of generally rectangular shape. The metal framework 11 in the illustrated embodiment is formed from a single steel strip which is bent into generally rectangular shape and is closed upon itself by overlapping the ends of the strip and suitably fasten- Obviously, the support frame could be made in others ways,

and the illustrated embodiment is by way of example 'only.

.central transverse axis of the framework with a pair of oppositely disposed apertures and 22, respectively,

which serve as bearings for a mandrel generally indicated at 24. Mandrel 24 includes a slot 26 along the length thereof for receiving the metal blank which is to be rolled, as will be explained more fully hereinafter, slot 26 being offset a short distance from the longitudinal axis of the mandrel. MandrelZd in the illustrated embodiment may be, for example, Ai-inch in diameter, and slot 26 may be ;.-inch wide and /s-inch deep. Mandrel 24 is bent at one end thereof at an angle slightly less than degrees from the axis of mandrel to form a handle portion 28.

A guide roller 39 is positioned adjacent mandrel 24, roller 3% being a tubular sleeve-like member which is supported for rotation by a pin member 32 which in turn is rigidly supported with respect to framework 11 in oppositely disposed apertures in the

respective sides

12 and 14. Pin member 32 has its ends peened to prevent movement of member 32 out of its supports in the

sides

12 and 14.

In order to permit the support framework 11 to receive another mandrel of different size,

sides

12 and 14 are provided with a second pair of bearing apertures 34 deep.

In using the device of the invention for rolling expansion anchors, a soft metal blank 42, such as the one shown in FIG. 5, is selected of a suitable length and width. for the particular anchor which is to be rolled. The thickness of the blank may be in the approximate range of -inch to V -inch for example. The metal blank 42 is preferably provided with a continuous unperforated and ungrooved surface on both sides thereof. The surfaces of the blank may be rough, as shown in the view of FIG. 5, or may be smooth. While the blank 42 is made of a soft metal such as aluminum, it has suf- -ficient rigidity to require the use of a mandrel for rollshown in FIG. 2 is used and a blank 40 having a size 1% x 2 inches is used, the l fii-inch dimension of the blank being rolled. The blank42 is laid across the surface of guide roll 3i) and mandrel 24 is turned to a position in which the edge of blank 42 can be inserted in slot 26. With the edge of blank 42 engaged with slot 26, mandrel '23 is then turned toward'the operator to thereby rotate mandrel 24 in a counterclockwise direction with respect to the view shown in FIG. 1 or in a clockwise direction with respect .to the View shown in FIG. 3. Rotation of mandrel 2d roils the blank 42 up'into the spirally wound form shown in FIG. 6. After the blank has been completely wound, mandrel 2% is then withdrawn from its bearings 2ft and 22 and the finished expansion anchor is free of the mandrel and ready for use. A /s-inch hole is drilled in the surface which isto receive the expansion anchor and the /s-inch lag screw or bolt expands the anchor, causing the anchor to embed itself into the surface of the hole in which the anchor is inserted.

The tool equipped with the

mandrels

24 and 38 can be used for rolling various sizes of anchors used in connection with the most popular or widely used screw and bolt sizes. For example, mandrel 38 which is assumed to have 'a j -inch outer diameter can be used for rolling an anchor sion being rolled, and a A-inch hole being drilled in the surface which receives the expansion anchor. An expansion anchor for a #14 metal cutting screw or for a At-inch lag screw is rolled from a 1 x l A-inch metal blank with the 1-inch dimension being rolled on a inch mandrel, and a 4 -inch hole being drilled in the surface which receives the expansion anchor. An expansion anchor for a /2-inch lag screw or bolt is rolled on a mandrel having a %-inch diameter from a metal blank having a size 3 /4 X 2 inches withthe 3 fii-inch dimension being tightly rolled.

As best seen in FIGS. 6 and 8, the finished expansion anchor includes an inner, longitudinal edge or planar portion 44 which extends laterally or radially inwardly from the spiral surface of the innermost turn of the anchor and toward the central longitudinal axis of the anchor at an angle which, in the illustrated embodiment, is substantially 90 degrees relative to a tangent to the arc of the spiral turns of the anchor. The angle of the inwardly extending edge 44 relative to the spiral turns of the anchor results from the fact that edge 44 was inserted in slot 26 of the mandrel during the rolling of the anchor, slot 26, as previously stated, being eccentric or off-set a short distance from the longitudinal axis of the mandrel. Edge 44 serves an important function in the finished anchor since it provides a sizing strip which frictionally engages the thread of the screw or bolt received by the anchor to provide a tight fit of the screw or bolt in the anchor. Due to the fact that the anchor is formed of a soft metal such as aluminum, the edge portion 44 can be easily bent from its initial substantially 90 degree angular position as produced by the slot 26 in the mandrel to any degree necessary, as, for example, to the dotted line positions A and B as shown in FIG. 8, to provide adjustment of .the effective internal diameter of the anchor to-insure a good fit of the screw or bolt in the anchor, or to permit adjustment of the tightness of the anchor in an undersize or oversize hole.

Thus, for example, when the edge 44 is bent to the position A shown in FIG. 8, in which edge 44 approaches a position in which it lies in the same arcuate path as the innermost spiral turn to which it is attached, the anchor accommodates a larger screw or has less tightness in an undersize hole than when the edge 44 is bent to the position B shown in FIG. 8. By bending the edge 44 to position B, in which edge 44 approaches a doubled-over relation to the innermost spiral turn, the effective internal diameter of the anchor can be reduced to provide a better fit for a small diameter screw, or to provide greater tightness of the anchor in an oversize hole.

The adjustment of the edge portion 44 may be made if desired prior to the insertion of the fastener into the formed anchor by inserting a suitable tool into the anchor strip or edge 44 tothe deand manually bending the sizing adjustment of the'internal sired position to give the proper diameter. of the anchor or to adjust the anchor tightness with respect to an undersize oroversize hole, as previously explained. However, because of the fact that the edge portion 44 is eccentric with respect to the longitudinal axis of the anchor due to its formation in the eccentric or offset slot of the mandrel, he innermost end of the entering screw fastener or the like will automatically cam the edge 44 either in a clockwise or counterclockwise direction as required without the necessity of using a separate tool to adjust the position of inturned edge 44.

- An important advantage of the offset position of the inturned edge or planar portion 44 relative to the longitudinal axis of the formed anchor is the fact that it locates the inturned edge 44 in a position in whichit does not interfere with'the entrance of the screw member into the anchor. Furthermore, the anchor may be wound in such manner as to cause the inturned-edge to lie either on the right or left side of the longitudinal axis when viewed from the outer or head end of theanchor, so that an entering right-hand screw will automatically cam the edge 44 ably provided with a cut-away corner portion generally indicated at 46, defined by the

edges

48, 50 and 52. The two

edges

48 and 52 extend inwardly perpendicularly to the side edges 54 and 56 of the blank for a distance substantially equal to the depth of the slot in the mandrel 24. The purpose of forming the cut portion 46 with the

straight edge portions

48 and 52 is to provide straight end edges on the edge portion of the blank which engages the slot of the mandrel (either edge 54 or 56), to thereby insure a better engagement of the blank with the slot in the mandrel than if the inclined edge 50 extended all the way to the edges 54 and 56 of the blank. The blank 42' may be Wound about either its transverse axis, in which case edge 54 engages the slot in the mandrel, or about its longitudinal axis, in which case the edge 56 engages the slot in the mandrel. I

As best seen in FIG. 9, the cut-away portion 46 lies in the innermost turn or turns of the formed anchor at the end of the anchor into which the screw or bolt is inserted. Due to the cut portion 4 6, the wall thickness of the anchor is reduced at this end, facilitating the insertion of the screw or bolt. By facilitating the insertion of the fastener member, the amount of force needed to insert the fastener is reduced, thereby greatly reducing the likelihood of fracturing or rupturing the outer surface of the wall which receives the anchor. v

The cut portion 46 also reduces the length of the bent edge portion 44' of FIG. 9 which forms the sizing-strip, so that the axial end of the strip 44 is spaced inwardly from the adjacent outer end of the anchor. This inward spacing of the end of strip 44' also facilitates the insertion of the fastener. When the anchor is used with screw fasteners of the type having an unthreaded neck portion of larger diameter than the remaining length of the screw member, the absence of the bent edge portion 44 adjacent the outer end of the anchor, due to the cut 46, provides an increased space to receive the unthreaded larger diameter neck portion. At the same time, the bent edge portion or sizingstrip 44' is present in the remaining length of the anchor for adjustably frictionally engaging the threaded surface of the screw member, as previously described.

Referring now to FIG. 10, it will be seen that the mandrel 24 is inserted from the left-hand'side of the framework 11, and that the eccentric slot 26 in the mandrel lies to the left of the longitudinal axis of the mandrel when viewed from the right in FIG. 10, and as seen in FIG. 11. The blank 42A is inserted in the winding device with the cut corner portion 46 of the blank facing toward the right-hand side of the framework 11 with respect to the view shown in FIG. 10. As previously explained, the cut corner portion 46 is located at the outer or head end of the formed anchor. The mandrel is rotated in a counterclockwise direction viewed from the right side of the framework 11 (or in a clockwise direction viewed from the handle end in FIG. 10) to produce the formed anchor 42A shown in FIG. 11, with the edge 44A offset to'the left of the longitudinal axis of the mandrel and of the formed anchor, when'viewed from the head end of the anchor as in FIG. 11. A right-hand screw entering the anchor member 42A formed as shown in FIG. 11 will cam the edge 44A in a clockwise direction to cause it to approach or extend beyond position A of FIG. 8 in which edge 44 forms substantially a continuation of the innermost spiral turn of the anchor and lies substantially in the same arcuate plane as the innermost spiral turn. The movement of edge 44A of anchor 42A of FIG. 11 in a clockwise direction will provide a larger internal diameter to accommodate a larger diameter screw, or will provide an anchor of less tightness in an' undersize hole.

On the other hand, when the mandrel 24 is positioned as shown in FIG. 12, being inserted from the right-hand side of the frame 11 and with the handle on the right-hand side, the eccentric slot 26 in the mandrel lies to the right of the longitudinal axis of the mandrel, when viewed from the right in FIG. 12. The blank 42' is inserted in the winding device with the cut corner portion 46 of the blank facing toward the right-hand side of the framework 11, just as in FIG. 10 when the mandrel was inserted from the left-hand side. The mandrel is rotated in a counterclockwise direction when viewed from the right-hand side of the framework 11, and also in a counterclockwise direction with respect to the handle of the mandrel. The formed anchor member will be as shown in PEG. 13 in which the inturned edge 44B lies to the right of the longitudinal axis CL of the mandrel and to the right of the longitudinal axis of the anchor. Thus, when a right-hand screw is inserted in the anchor 423, the innermost end or tip end of the right-hand screw will cam the edge 443 in a counterclockwise direction about its pivotal connec- F tion to the innermost spiral turn to cause edge 44 to overlap or be doubled over with respect to the innermost spiral turn of which it forms a continuation, as seen at B in FIG. 8. With the inturned edge 44B positioned as at B in FIG. 8, the thickness of the'anchor member is increased, thereby reducing the internal diameter of the anchor to accommodate a smaller diameter screw, or to provide increased tightness of the anchor in an oversize hole.

It can be. seen that by selectively positioning the mandrel 24 either as shown in FIGS. l-l1, or alternatively as shown in FIGS. 12-13, the direction of offset of the inturned edge 44 can be controlled to lie either to the left or to the right of the longitudinal axis of the'formed anchor, to thereby cooperate with the screw fastener to permit the screw fastener to automatically cam the inturned edge to a position in which it increases or decreases the eifectiveinternal diameter of the anchor member formed on a given mandrel to accommodate the anchor to the screw fastener positioned therein, or to control the tightness of the formed anchor relative to the hole in which it is positioned.

It can be seen from the foregoing that there is provided in accordance with this invention an apparatus for forming expansion anchors for fastenings such as screws and bolts which has. great practicalutility in that it permits the expansion anchor to be rolled on the job as required without the necessity of the mechanic carrying with him a number of various sizes f P eformed anchors. The improved expansion anchor of the invention can be rolled very quickly using the apparatus hereinbefore described at. an expense which is considerably less than that of the preformed expansion anchors currently in use.

tures, brackets, screw insulators, washline hooks, plumbing fixtures and pipes, guy wire hooks, drop cables for utility lines, antennas, picture hooks, and for a wide variety of other installation requirements.

Furthermore, there is provided in accordance with this invention an anchor member and a method of winding such anchor members which'provides an interned edge portion on the anchor permitting adjustment of the internal diameter of the anchor to conform to the fastener member inserted in the anchor, or permitting adjustment of the tightness of the wound anchor with respect to the hole in which it is positioned. The eccentric or offset location of the inturned edge or sizing strip of the anchor permits the sizing strip to cooperate with the screw fastener to automatically cam the sizing strip to a properly adjusted position, and furthermore, permits selective location of the eccentric inturned edge to one side or the other of the longitudinal axis of the anchor, depending on whether it is desired to increase or reduce the internal diameter of the anchor member, or to provide greater or lesser tightness of the anchor in the hole in which it is positioned.

While there has been shown and described a particular embodiment of the invention, it'will be obvious to those skilled in the art that various changes and modifications can be made therein without departing from the invention and, therefore, it is aimed to cover all such changes and modifications as fall within the true spirit and scope of the invention. a

What I claim as my invention is: V

1. An expansion anchor for screws, bolts, and the like, comprising'a blank of metal spirally wound on itself to include more than one radially superposed spiral turn and forming a hollow tubular member of generally cylindrical shape, the radially innermost spiral turn of said anchor terminating in a substantially planar portion extending radially inwardly toward the opposite portion of said spiral turn, said planar portion extending axially of said anchor, said planar portion having one axial end thereof. substantially flush with the normally inwardly disposed axial end of said anchor, said planar portion having a normally axially outermost end which is spaced axially inwardly from the normally outwardly disposed axial end of said anchor, the normally axially outermost edge of at least the innermost spiral turn being spaced for at least a portion thereof axially inwardly from the normally outermost axial end of said anchor and joining said normally axially outermost end of said planar portion whereby to reduce the radial thickness of the anchor at the normally outermost axial end of said anchor, said planar portion being bent radially inwardly about a bend axis lying adjacent'to but in'eccentric offset relation to a first diametral plane of said anchor, said planar portion extending substantially parallel to said first diametral plane and substantially perpendicularly to a second diametral plane of said anchor which lies substantially perpendicular to said first diametral plane, the radial length of said planar portion being so dimensioned that the radially inner edge of said planar portion lies substantially adjacent said second diametral plane.

2. An expansion anchor for screws, bolts, and the like, comprising a blank of metal spirally wound on itself to include more than one radially superposed spiral turn and forming a hollow tubular member of generally cylindrical shape, the radially innermost spiral turn of said anchor terminating in -a substantially planar portion extending radially inwardly toward the opposite portion of said spiral turn, said planar portion extending axially of said anchor, said planar portion having one axial end thereof substantially flush with the normally inwardly disposed axial end of said anchor, said planar portion having a normally axially outermost end which is spaced axially inwardly from the normally outwardly disposed axial end of said anchor, the normally axially outermost edge of a least the innermost spiral turn being tapered for at least a portion of its length axially inwardly from the normally outermost axial end of said anchor and joining said normallyaxially outermost end of said planar portion whereby to reduce the radial thickness of the anchor at the normally outermost axial end of said'anchor, said planar portion being bent radially inwardly about a bend axis lying adjacent to but in eccentric ofiset relation to a first diametral plane of said anchor, said planar portion extending substantially parallel to said first diametral plane and substantially perpendicularly to a second diametral plane of said anchor which lies substantially perpendicular to said first diametral plane, the radial length of said planar portion being so dimensioned that the radially inner edge of said planar portion lies substantially adjacent said second diametral plane.

3. An expansion anchor for screws, bolts, and the like, comprising a blank of metal spirally wound on itself to include more than one radially superposed spiral turn and forming a hollow tubular member of generally cylindrical shape, the radially innermost spiral turn of said anchor terminating in a substantially planar portion extending radially inwardly toward the opposite portion of said spiral turn, said planar portion extending axially of said anchor, said planar portion having one axial end thereof substantially flush with the normally inwardly disposed axial end of said anchor, said planar portion having a normally axially outermost end which is spaced axially inwardly from the normally outwardly disposed axial end of said anchor, the normally axially outermost edge of at least the innermost spiral turn being spaced for at least a portion thereof axially inwardly from the normally outermost axial end of said anchor and joining said normally axially outermost end of said planar por- 10 tion whereby to reduce the radial thickness of the anchor at the normally outermost axial end of said anchor, said planar portion being bent radially inwardly about a bend axis lying adjacent to but in eccentric ofiset relation to a first diametral plane of said anchor, said planar portion extending substantially parallel to said first diametral plane and substantially perpendicularly to a second diametral plane of said anchor which'lies substantially perpendicular to said first diametral plane, the radial length of said planar portion being no greater than the radius of said innermost turn so that said planar portion does not cross said second diametral plane.

References Cited in the file of this patent UNITED STATES PATENTS 1,350,562 Ogden Aug. 24, 1920 2,150,866 Sipe Mar. 14, 1939 2,390,937 Holland Dec. 11, 1945 3,007,239 Lermont Nov. 7, 1961 I FOREIGN PATENTS 155,021 Australia Feb. 3, 1954 1,023,043 France Dec. 24, 1952 OTHER REFERENCES Afiidavit of Mr. C. W. Tomlin, executed March 28, 1962, cited in applicants prior case Serial No. 61,041.

Claims

1. AN EXPANSION ANCHOR FOR SCREWS, BOLTS, AND THE LIKE, COMPRISING A BLANK OF METAL SPIRALLY WOUND ON ITSELF TO INCLUDE MORE THAN ONE RADIALLY SUPERPOSED SPIRAL TURN AND FORMING A HOLLOW TUBULAR MEMBER OF GENERALLY CYLINDRICAL SHAPE, THE RADIALLY INNERMOST SPIRAL TURN OF SAID ANCHOR TERMINATING IN A SUBSTANTIALLY PLANAR PORTION EXTENDING RADIALLY INWARDLY TOWARD THE OPPOSITE PORTION OF SAID SPIRAL TURN, SAID PLANAR PORTION EXTENDING AXIALLY OF SAID ANCHOR, SAID PLANAR PORTION HAVING ONE AXIAL END THEREOF SUBSTANTIALLY FLUSH WITH THE NORMALLY INWARDLY DISPOSED AXIAL END OF SAID ANCHOR, SAID PLANAR PORTION HAVING A NORMALLY AXIALLY OUTERMOST END WHICH IS SPACED AXIALLY INWARDLY FROM THE NORMALLY OUTWARDLY DISPOSED AXIAL END OF SAID ANCHOR, THE NORMALLY AXIALLY OUTERMOST EDGE OF AT LEAST THE INNERMOST SPIRAL TURN BEING SPACED FOR AT LEAST A PORTION THEREOF AXIALLY INWARDLY FROM THE