US3884004A

US3884004A - Fastening insert for concrete structures

Info

Publication number: US3884004A
Application number: US383463A
Authority: US
Inventors: William L Douma; Herman N Douma
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-07-27
Filing date: 1973-07-27
Publication date: 1975-05-20
Anticipated expiration: 1992-05-20

Abstract

A fastening insert for concrete structures comprises a preferably tapered body member formed preferably of inexpensive, high density cellular plastic material which may be either conveniently molded or extruded into the desired shape for attachment to a concrete mold form to provide a readily accessible exposed base for selectively attaching fixtures or the like to the concrete structure after the mold form is removed. Molded through holes or apertured flanges may be provided to accept a nail or the like to secure the body member in position on the mold form during formation of the concrete structure. The base of the body member may be ridged, roughened, apertured, or dimpled to provide a plurality of selectively positioned recesses to aid in initiating the engagement of a threaded fastener therewith. Stabilizing means which may comprise rod-like extensions or flanged collars emanating from the body member may be provided to increase the interengagement between the body member and the surrounding concrete.

Description

United States Patent 1 Douma et al.

[ FASTENING INSERT FOR CONCRETE STRUCTURES [76] Inventors: William L. Douma, P0. 53

Whippany Ave, West Paterson, NJ. 07424; Herman N. Douma, 488 Berkshire Rd., Ridgewood, NJ. 07450 22 Filed: July 27,1973

21 Appl.No.:383,463

[451 May 20, 1975 386,674 4/1965 Switzerland 52/704 Primary Examiner-John E. Murtagh Attorney, Agent, or FirmJesse Woldman ABSTRACT A fastening insert for concrete structures comprises a preferably tapered body member formed preferably of inexpensive, high density cellular plastic material which may be either conveniently molded or extruded into the desired shape for attachment to a concrete mold form to provide a readily accessible exposed base for selectively attaching fixtures or the like to the concrete structure after the mold form is removed. Molded through holes or apertured flanges may be provided to accept a nail or the like to secure the body member in position on the mold form during formation of the concrete structure. The base of the body member may be ridged, roughened, apertured, or dimpled to provide a plurality of selectively positioned recesses to aid in initiating the engagement of a threaded fastener therewith. Stabilizing means which may comprise rod-like extensions or flanged collars emanating from the body member may be provided to increase the interengagement between the body member and the surrounding concrete.

10 Claims, 14 Drawing Figures PFJENTEU M20195 SHEET 10F 3 FIG. 1

FIG. 2

FIG. 3

FIG. 4

PATENTEB HAYZOIBTS 1. 884, 004

sum 3 OF 3 FASTENING INSERT FOR CONCRETE STRUCTURES BACKGROUND OF THE INVENTION 1. Field of the Invention The invention is directed to the field of support means and principally to a fastening insert for concrete structures and the like.

2. Description of the Prior Art Prior art devices, designed to permit the support or suspension of brackets, hangers, fixtures and the like from concrete walls or ceilings while avoiding the necessity for drilling directly into the concrete and applying an anchor thereto, generally comprised relatively expensive and complex assemblies fabricated generally of metal and adapted to be fastened directly to the base of a mold form prior to the addition of concrete thereto. After the concrete had set, the mold form was removed, permitting access to the exposed base of the embedded device. Early devices of this type featured a non-adjustable,internally threaded interior portion, as exemplified in U.S. Pat. No. 1,218,378, issued Mar. 6, 1917 to H. Dippel. Not only were such devices relatively expensive, but they had the additional drawback of requiring a time consuming, inefficient, and tedious operation to precisely locate such devices on the mold form to accommodate fixedly spaced fasteners attached to fixtures, supports, outlet boxes, and the like. Later devices designed to alleviate this problem are exemplified in US. Pat. No. 1,922,479, issued Aug. 15, 1933 to P. N. Joslin, which discloses a concrete insert employing a threaded member slidably disposed within a flanged housing. Although such devices required somewhat less critical positioning than did the former devices, adjustment was limited however to movement along a single axis. Due to the nature of their construction and fabrication, such prior art devices comprised a number of exposed joints such that the probability of leakage of concrete into the interior of the device presented an additional complication which necessitated further measures to insure that a proper seal was provided, thereby further increasing their expense and complexity.

SUMMARY OF THE INVENTION The invention overcomes the problems and limitations noted above with respect to such prior art devices by providing a readily formable plastic fastening device which is more economical, versatile, reliable, and convenient than such devices. The device comprises a preferably tapered body member which may be either molded or extruded preferably from high density cellular material capable of accepting and securely retaining a threaded fastener threadably attached thereto. The body member may be inexpensively foam molded to provide an essentially cellular internal structure and a thin, solid integral skin or outer covering, whereby a threaded fastener such as a wood or sheet metal screw, or the like, may be readily inserted into and secured to the base of the body member at any desired location. Thus, by providing a given exposed base surface, problems of alignment and adjustment are effectively eliminated within the limits of the available base surface area. The body member may be selectively formed to define, for example, a generally square, rectangular, or circular transverse cross section with tapered sides coverging towards a lower portion terminating in a bottom surface which may be scored, ridged, recessed, or apertured to provide a convenient starting point for the attachment of a threaded screw or the like thereto. The tapered body member configuration is adapted to permit the surrounding concrete to brace the embedded insert against longitudinal displacement so that the insert is prevented from being pulled out of the concrete when supporting an external member attached thereto. The body member may be rapidly and simply secured to the mold form by driving a nail longitudinally through the body member and into the mold form base, or by inserting such nails through apertured flanges selectively positioned about the periphery thereof, and into the mold form base. In a further embodiment, the body member is secured to the mold form by a strap bounding the top and sides of the body member and secured to the mold form base by apertured foot portions frangibly connected to the strap and readily parted therefrom after the mold form is removed. Stabilizing collars or rods may be provided to more securely anchor the body member in the concrete. It is therefore an object of this invention to provide an improved concrete insert.

It is another object of this invention to provide an in expensive fastener accepting device for concrete structures.

It is a further object of this invention to provide an inexpensive, readily manufactured concrete insert formed from molded plastic foam material.

It is yet another object of this invention to provide an inexpensive concrete insert formed from extruded plastic material.

It is still a further object of this invention to provide an inexpensive plastic concrete insert having premolded fastener receiving apertures selectively formed therein.

It is yet a further object of this invention to provide a concrete insert in which substantially the entire base thereof may be employed to accept a threaded fastener at any desired location therein.

Other objects and features of this invention will be pointed out in the following description and claims, and illustrated in the accompanying drawings, which disclose, by way of example, the principles of the invention and the best mode contemplated for carrying it out.

BRIEF DESCRIPTION OF THE DRAWINGS In the Drawings:

FIG. 1 is an elevational view, partly cut away and partly in section, of a concrete insert constructed in accordance with the concepts of the invention.

FIG. 2 is an elevational view, in section, of the device of FIG. 1 showing a fastener attached thereto.

FIG. 3 is an elevational view, in section, of a further embodiment of a concrete insert constructed in accordance with the concepts of the invention.

FIGS. 4 and 5 are perspective views, partly cut away and partly in section, of further embodiments of a concrete insert constructed in accordance with the concepts of the invention.

FIG. 6 is a fragmentary perspective view, partly cut away and partly in section, of an embodiment of the base portion of a concrete insert constructed in accordance with the concepts of the invention.

FIG. 7 is an elevational view, partly cut away and partly in section, of a further embodiment of a concrete insert constructed in accordance with the concepts of the invention.

FIGS. 8 and 9 are fragmentary perspective views, partly cut away and partly in section, of lengths of selectively formed plastic extrusions for fabricating further embodiments of a concrete insert constructed in accordance with the concepts of the invention.

FIG. 10 is a fragmentary perspective view of a further embodiment of the base portion of a concrete insert constructed in accordance with the concepts of the invention.

FIG. 1 1 is a perspective view, partly cut away, of yet another embodiment of a concrete insert constructed in accordance with the concepts of the invention.

FIG. 12 is a front elevational view, partly cut away and partly in section, of the device of FIG. 11 embedded in a section of concrete.

FIGS. 13 and 14 are fragmentary perspective views, partly cut away and partly in section, of still further embodiments of concrete inserts constructed in accordance with the concepts of the invention, illustrating the employment of stabilizing means therewith.

Similar elements are given similar reference characters in each of the respective drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to FIGS. 1 and 2, there is shown a concrete insert 20 constructed in accordance with the concepts of the invention. The insert 20 comprises a body member 22 having an interior of preferably high density cellular material 24 surrounded by a thin solid integral skin 26. The body member 22 tapers convergingly from an upper portion 28 to a lower portion 30 which terminates in a bottom surface 32 adapted to seat against an upper surface 34 of a concrete mold form base 36. The body member 22 is selectively fastened in a predetemined position on the mold form base 36 by a nail 38 driven substantially centrally longitudinally through the skin 26 and interior cellular material 24 of the body member 22, and into engagement with the mold form base 36, so that the body member bottom surface 32 is seated tightly against the upper base surface 34. A mixture of concrete 40 may now be poured into the mold form and allowed to set, thereby embedding the insert 20 in a selective position within the surrounding concrete 40. The body member 22 is provided with a selectively tapered external configuration to prevent it from being pulled out of the surrounding concrete 40 while supporting an external member fastened thereto. As may be clearly seen in FIG. 1, the concrete 40 is caused to envelope the body member 22 in such manner as to wedgingly brace it against longitudinal displacement in a direction towards the bottom of FIG. 1. Upon removal of the mold form, the bottom surface 32 of the insert 20 is disposed flush with a bottom surface 42 of the concrete 40 and is completely exposed and readily accessible to receive a threaded fastener such as a self-tapping screw 44 (FIG. 2) for attaching, for example, an outlet box 46 to the surface 42 of the concrete 40. To effect the aforesaid attachement, the screw 44 is inserted through a suitable opening 48 in the box 46 and threaded into a selective position in the exposed bottom surface 32 of the body member 22 and into engagement with the cellular material 24 forming the interior of the body member 22. The preferably high density cellular material 24, which may comprise any one of a number of plastic materials such as polyethylene, polypropylene, polystyrene, or like readily moldable compositions, has the advantageous property of providing a secure restraint for the screw 44 while obviating the necessity for pre-drilling, molding, or otherwise forming a prior hole in the insert. It has been found that the pull-out strength of a No. 14 sheet metal screw having spaced threads with an approximate threaded depth engagement in a inch thick specimen of high density foam molded styrene may exceed 200 pounds. The tapered body member 22 may have a round, oval, elliptical, square, rectangular, or polygonal transverse cross section, or combination thereof, if necessary or desirable, without departing from the spirit of the invention and within the concepts herein disclosed. Although the nail 38 may be driven through the outer skin 26 and the cellular material 24, one or more molded or pre-drilled holes may be provided extending longitudinally either through the entire length of the body member 22, or through a selective length thereof to aid in initiating the entry of the nail or like fastener into the body member 22. For example, in the embodiment illustrated in FIG. 3, there is shown a partially tapered body member 50 having an enlarged upper portion 52 comprising a generally non-tapered shoulder-like upper portion 54 extending inwardly as at 56 to communicate with a generally non-tapered lower portion 58 which terminates in a base surface 59. The shoulder-like upper portion 54 thus overhangs the body member lower portion 58 and is provided with a pair of longitudinally extending molded-through holes 60, 60 selectively dimensioned to accept the shank of a corresponding fastening means such as a

nail

62, 62 therethrough. The body member 50 may thus be rapidly and securely selectively fastened in a predetermined location on the mold form base 64 by inserting the nails 62, 62' through each of the respective holes 60, 60' and driving them into the base 64 substantially as shown. In this case, the nails 62, 62' do not occupy any portion of the body member base surface 59, as is the case in the embodiment illustrated in FIG. 1, but are spaced outwardly from the outer periphery thereof, thus providing a larger base area for subsequent engagement by a fastener such as 44.

Referring now to FIGS. 4 and 5, there are shown two further embodiments of a

concrete insert

66, 68, respectively, constructed in accordance with the concepts of the invention. Insert 66 comprises a generally tapered body member 70 having a substantially square transverse cross section, while the insert 68 comprises a generally tapered body member 72 having a substantially circular cross section. It will, of course, be readily appreciated by those skilled in the art that the external contour of either of the

body members

70, 72 may be modified to define any one of the contours described hereinabove. As shown in the partly cut-away section in each of FIGS. 4 and 5, the interior of each of the

body members

70, 72 is comprised preferably of the same high density cellular material 24 used in the fabrication of insert 20, while the exterior is also similarly defined by a relatively thin,

integral skin

74, 74 respectively, essentially duplicative of element 26 of FIGS. 1 and 2. The body member 70, shown in FIG. 4, comprises an upper portion 76 having a pair of

flanges

78, 78 extending transversely outwardly from the periphery of an upper surface 80 thereof. Each of the

flanges

78, 78 is provided with an

aperture

82, 82, respectively, axially oriented generally parallel to the longitudinal axis of the body member 70. The body member 72 of insert 68 is similarly pro ided with a given number, namely, four longitudinally

apertured flanges

84, 84', 86, 86', extending transversely outwardly from the periphery of an upper surface 88 of an upper portion I 90 thereof. The number of flanges, in either case, may

be increased or decreased, if necessary or desirable. Alternatively, a suitable apertured flanged collar (not shown) may be employed with equal effectiveness. Thus, each of the

body members

70, 72 may be securely fastened to a mold form base such as 36 by inserting a nail such as 38 (FIG. 1) through each of the respective apertures in the

flanges

78, 78 84, 84, and 86, 86, and driving it into the mold form base. As pointed out above with respect to the embodiment illustrated in FIG. 3, the nail receiving apertures such as 82, 82' are located beyond the periphery of the base of the body member, so that the nails employed to fasten the

body member

70 and 72 to the mold form base occupy no part of the bottom surfaces thereof, thus providing an unencumbered fastener receiving bottom surface area. The apertured flanges shown in the embodiments illustrated in FIGS. 4 and 5 may, alternatively, be extended longitudinally in rib-like fashion (not shown) along the length of the respective sides of the

body members

70, 72, to provide an increased nail shank engaging structure, where necessary or desirable. The use of simple, common nails to fasten each of the aforementioned embodiments to the mold form base has been described heretofore merely for the sake of simplicity, and is not intended as a limitation on the type of fastener which may be similarly employed. For example, elongate selectively threaded wood screws (not shown) may be utilized to effect the desired attachment by threading them into the mold form base either manually, or by the use of well-known automatically operated screw driving tools (not shown) in a rapid and highly efficient manner. It will, of course, be readily apparent to those skilled in the art that such fasteners may be entirely eliminated and a suitable adhesive (not shown) substituted therefore to effect an adequate bond between the base surface of the body member and the mold form base. Alternatively, both an adhesive and nails or similar fasteners may be employed to attach the body member to the mold form base. Although the bottom surface of each of the embodiments described heretofore may comprise simply a relatively smooth flat surface, a selectively formed bottom surface 92 as shown in FIG. 6 may be provided to enhance the convenience and utility of the instant invention. The bottom surface 92 comprises a plurality of small indentations 94 which may be formed individually or, as illustrated, by the intersection of a series of preferably regularly spaced grooves 96 disposed in a crosshatched pattern, substantially as shown. The indentations 94 may thus be used to provide a convenient starting recess for a self-tapping screw or the like. The grooves 96 may either be molded into the base surface 92 simultaneously with the formation of the concrete insert, or formed therein in a subsequent operation. In the latter case, the thin outer skin of the molded insert will have been pierced or cut, thereby exposing a portion of the interior cellular material, whereas in the former case, the skin will be contiguous and unbroken throughout the base surface 92. In a similar manner, there may be further provided a series of preselectively dimensioned longitudinally extending cavities 98 communicating with the base surface 92 where, for example, it is desired to thread a relatively large shanked self-tapping screw into the insert with a smaller degree of effort than would be required in the absence of such cavities 98. Although the cavities 98 illustrated in FIG. 6 have been molded in the insert and are, consequently, surrounded by a thin solid intergral skin 100, they may be formed therein subsequent to the molding operation, in which case the interior cellular material will be exposed along the walls defining each of the cavities 98. It has been found that, in the case of molded-in cavities in foam molded cellular structures, the skin 100 surrounds the thread area, thereby providing increased holding power approximately 20 percent greater than that obtained when the skin 100 was absent. The peripheral configuration of the base surface 92, although shown as essentially circular, will, of course, conform generally to the particular insert contour employed, and may take on the general base form of any one of the embodiments described heretofore. Additionally, the base surface 92 may be disposed flush with the bottom of the insert, or may be selectively-recessed, as illustrated in FIG. 10 at 102, and inset within a surrounding shoulder portion 104 which is arranged to lie flat against the mold form base to prevent the intrusion of the poured concrete into the recessed base surface 102. In the embodiment illustrated in FIG. 10 there is further provided a clearance hole 106 for receiving a nail such as 38 therethrough. By recessing the base surface 102, as shown, the end of the nail protruding beyond the base surface 102 after the removal of the mold form base may be severed from the remaining shank portion flush with the base surface 102, and, accordingly, interiorly of the surrounding concrete surface, to prevent any interference with a member to be fastened to the insert.

Referring now to FIG. 7 there is shown another embodiment of a concrete insert 108 constructed in accordance with the concepts of the invention, and comprising a tapered body member 110 similar to body member 22 of FIG. 1. In this case, however, a sloped flange 112 is disposed adjacent a lower portion 114 of the body member 110 and includes one or more transverse apertures 116 extending through the flange 112 perpendicular to the sloped upper surface thereof. The body member 110 may thus be secured to the mold form base 36 by nails such as 118 inserted through the respective apertures l 16 and driven into the mold form base 36. The flange 112 may comprise either a continuous collar-like extension completely surrounding the lower portion 114 of the body member 110, or, two or more separate segments selectively spaced thereabout. To increase the stability of the insert in the surrounding concrete, embodiments such as illustrated in FIGS. 13 and 14 may be employed. The stabilizing means illustrated in FIG. 13 comprises an elongate rod 120 extending generally transversely through an upper portion 122 of a concrete insert 124, whereas the stabilizing means illustrated in FIG. 14 comprises a flanged collar 126 attached to the periphery of an upper portion 128 of a concrete insert 130. The rod 120 and the collar 126 serve to provide a greater area of contact between the

inserts

124 and 130, respectively, and the surrounding concrete (not shown) thereby assisting to hold the respective inserts more fimly therein. Although only two forms of stabilizing means are shown,

it will be readily apparent to those skilled in the art that many other shapes may be readily employed in a similar fashion without departing from the spirit of the invention and within the concepts herein disclosed, and that several such stabilizing means may be employed with a single insert to increase the stabilizing effect thereof.

The rod 120 and collar 126 may be formed either of metallic or plastic material, as desired and, in the latter case, may be formed integrally with the associated body member during the molding process. The particular location of the stabilizing means in relation to the upper and lower portions of the body member may, of course, be varied without affecting the effectiveness thereof, provided the stabilizing means are located sufficiently above the surface of the concrete to prevent failure of the concrete due to shear stress.

Referring now to FIGS. 8 and 9, there are shown, by way of example, and not as limitation thereof, two extruded plastic elongate segments 132 and 134, respectively, which may be selectively sectioned to form other embodiments of a concrete insert constructed in accordance with the concepts of the invention. The segment 132 may be cut along the respective dotted lines 136 to form a plurality of inserts 138, each having apair of opposing tapered sides 140, together with flanged portions 142 which extend outwardly from the sides 140 adjacent an upper portion 144 of the insert 138. Each of the inserts 138 further comprises a substantially flat base or bottom surface 146 which may be altered, if necessary or desirable, to provide a roughened, grooved, ridged, apertured, or recessed surface, sub' stantially as described heretofore. The segment 134 illustrated in FIG. 9 is generally similar to segment 132 but further includes additional flanged portions 148 extending outwardly from opposing tapered surfaces 150 adjacent lower portion 152 of the segment 134 which may be similarly cut along the dotted lines 154 to provide a similar plurality of inserts 155. The upper and lower

flanged portions

142 and 148, respectively, may subsequently be appropriately apertured to receive a fastening means such as a nail or the like to attach the insert to the mold form base. The particular extruded shapes illustrated in FIGS. 8 and 9 are exemplarly, merely. and are not intended to be exhaustive of the various shapes which may be readily obtained in a similar manner simply by employing a desired extruder exit configuration (not shown) in a manner well known to those skilled in the art.

Turning now to FIGS. 11 and 12 there is shown a further embodiment of a concrete insert 156 constructed in accordance with the concepts of the invention. The insert 156 comprises a tapered body member 158 which is fastened to the mold form base 36 by a strap 160 having apertured foot portion 162 connected to the remaining portion of the strap 160 by frangible sections 164. The body member 158 is selectively recessed along a top portion 166, as at 168, to permit a selective length of the strap 160 to be constrained therein, while the remaining length of the strap 160 extends downwardly adjacent opposing sides of the body member 158. After the body member 158 is selectively positioned on the mold form base 36, it is fastened thereto by nails 170 or like fasteners inserted into the respective apertures in the foot portions 162 and driven into the mold form base 36, as shown. The concrete is then poured thereover and permitted to set. after which the mold form base 36 is removed to expose the bottom surface of the insert 156. In this case. however, the foot portions 162 and the associated nails 170 may be readily removed from the remainder of the strap simply by gripping the exposed shanks of each of the nails in the jaws ofa pliers-like tool 172 and pulling in a direction away from the concrete, thereby causing the foot portions to hingedly rotate about the interconnecting frangiblesections 164 which are designed to readily fracture under such stress, permitting the convenient and rapid removal of the foot portions 162 and associated nails 170. The task of removing the exposed portion of the nails 170 to provide an unencumbered exposed concrete surface is thus conveniently eliminated. The body member 158 of insert 156 is, of

course, still firmly embedded in the concrete by virtue of the tapered form thereof, and the removal of the strap foot portions 162 willin no way affect the reliability of interengagement between the body member 158 and the surrounding concrete. Although the body member 158 is shown as having a generally rectangular transverse cross section, it will be clear that any of the forms described and illustrated heretofore may be adopted for use in a similar manner according to the spirit of the invention and within the concepts herein disclosed.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A fastening device adapted to be embedded in concrete comprising: an integral body member of generally uniform composition and formed of high density foam molded cellular plastic material, said body member having an upper portion and a lower portion, said upper portion being larger than said lower portion and having an undersurface tapering convergingly towards and overhanging said lower portion, said upper portion having at least one elongate aperture extending generally longitudinally along an axis located outside the perimeter of said lower portion, said aperture being arranged to accept a fastener for attaching said fastening device to a concrete mold form, said lower portion of said body member terminating in a generally contiguous planar bottom surface arranged to seat intimately against a concrete mold form and be totally exposed upon removal of the mold form to permit the attachment of an external member to said fastening device at said body member is formed from molded foam plastic material.

61A fastening device as defined in claim 5 wherein said plastic material is polyethylene.

7. A fastening device as defined in claim 5 wherein said plastic material is polypropylene.

8. A fastening device as defined in claim 5 wherein said plastic material is polystyrene.

10. A fastening device as defined in claim 9 wherein said flange portions are disposed generally adjacent said upper portion of said body member.

Claims

1. A fastening device adapted to be embedded in concrete comprising: an integral body member of generally uniform composition and formed of high density foam molded cellular plastic material, said body member having an upper portion and a lower portion, said upper portion being larger than said lower portion and having an undersurface tapering convergingly towards and overhanging said lower portion, said upper portion having at least one elongate aperture extending generally longitudinally along an axis located outside the perimeter of said lower portion, said aperture being arranged to accept a fastener for attachIng said fastening device to a concrete mold form, said lower portion of said body member terminating in a generally contiguous planar bottom surface arranged to seat intimately against a concrete mole form and be totally exposed upon removal of the mold form to permit the attachment of an external member to said fastening device at any desired location within said bottom surface.

2. A fastening device as defined in claim 1 wherein said body member has a generally rectangular transverse cross section.

3. A fastening device as defined in claim 1 wherein said body member lower portion has a generally circular cross section.

4. A fastening device as defined in claim 1 wherein said body member lower portion has a generally uniform crosssection throughout its length.

5. A fastening device as defined in claim 1 wherein said body member is formed from molded foam plastic material.

6. A fastening device as defined in claim 5 wherein said plastic material is polyethylene.

9. A fastening device as defined in claim 1 wherein said fastener accepting means includes apertured flange portions extending outwardly from the periphery of said body member.