Gypsum Board Fastener

Abstract

Gypsum wallboard having an unbroken front face and means for affixing the wallboard to a support consisting preferably of a blind fastener extending into the body of the board through the back face, grasping the board by enlarged portions of the fastener disposed within the body of the board.

Description

This invention relates to affixing fastening means to gypsum wallboard, and particularly to blind fasteners having enlarged portions disposed within the body of the wallboard.

The most common ways of fastening gypsum wallboard to a structure are by screws or nails extending through the board into a base structure or by adhesive application. Screws or nails have unsightly heads remaining in view after application. Adhesive application lacks positive or mechanical affixation, particularly while the adhesive is wet or unset.

An object of the present invention is the provision of a novel immediate positive mechanical affixation of wallboard. It is a particular object to provide such affixation without any evidence of such affixation apparent on the wallboard face.

It is a further object to provide a novel method of attaching anything to gypsum wallboard or vice versa.

These and other objects will be clearly understood in considering the preferred embodiments as set forth in the specification and shown in the drawings in which:

FIG. 1 is an isometric view of a section of a wall with gypsum board mounted in accordance with the invention.

FIG. 2 is an isometric view of a section of a ceiling with gypsum board suspended in accordance with the invention.

FIG. 3 is a bottom view of a blind rivet suitable for use in accordance with the invention.

FIG. 4 is a cross-sectional view of the blind rivet of FIG. 3 taken along line 4--4.

FIG. 5 is a side view of a self-drilling mandrel, in accordance with the invention.

FIG. 6 is an end view of the self-drilling mandrel of FIG. 5.

FIG. 7 is a cross-sectional view of the edge of a ceiling gypsum board during the process of affixing suspending means thereto in accordance with the invention.

FIG. 8 is a cross-section similar to FIG. 7 on completion of the said affixing process.

FIG. 9 is a rivet gun for self-drilling blind rivets, in accordance with the invention.

Referring to FIG. 1, there is shown a vertical wall 10, in section, with two gypsum wallboards 12, 12, forming vertical joint 14. Affixed to the back face 16 of each wallboard 12 are a plurality of horizontally spaced, parallel elongate mounting strips 18. Mounting strips 18 are affixed to the back face 16 by blind rivets 20, 20.

Mounting strips 18 have a cross-section of two oppositely directed flanges, upper flange 22 and lower flange 24, in spaced parallel planes, adjoined by a central horizontal web 26. Rivets 20, 20 extend through holes 28, 28 in upper flange 22 and into the board back face 16.

The lower flange 24 of each mounting strip 18 is interlocked with spaced vertical studs 30 by their disposition behind upwardly directed hangers 32 bent outwardly and upwardly from the two opposite faces of studs 30. Studs 30 are affixed to the floor and ceiling of a room by usual means (not shown).

In FIG. 2, a ceiling 40 is shown, including two gypsum wallboards 42, 42 forming joint 44. Affixed to the back face 46 of each wallboard 42 are a plurality of spaced parallel elongate mounting strips 48, including one mounting strip 48 adjacent each joint 44 and one mounting strip 48 halfway therebetween. Mounting strips 48 are affixed to the back face 46 by blind rivets 50, 50.

Mounting strips 48 include an upwardly extending bulbed flange 52 and a lower horizontal flange 54. Bulbed flange 52 has an elongate, semi-circular rib 56 in approximately the middle thereof. Rivets 50, 50 extend through holes 58, 58 in the lower flange and into the board back face 46.

The bulbed flange 52 of each mounting strip 48 is interlocked with spaced parallel T-bars 60, a common available means for supporting elements having the bulbed shape of flange 52. T-bars 60 have a pair of opposed, resilient, bulbed sidewalls 62, 62 for receiving and holding therebetween one bulbed flange 52 or a pair of oppositely disposed bulbed flanges 52, 52. A top wall 64 extends outwardly forming flanges 66 which have suitable clips 68 grasped thereunder and extending up and over a suitable carrying channel 70.

Rivet 50, which is the same as rivet 20, is shown in FIGS. 3 and 4, and a mandrel 80 which is used with rivet 50 is shown in FIGS. 5 and 6.

Rivet 50 includes a circular head 82 and a cylindrical stem 84. A continuous elongate cylindrical opening 86 extends axially through the head 82 and stem 84, for the insertion of a mandrel 80. The stem 84 includes a plurality of axially weakened sections 88 at the bottom thereof. The axially weakened sections could be spaced upwardly from the very bottom of stem 84, however the preferred form is as shown, a plurality of axially extending sections 88 with axially extending slots 90 therebetween.

Mandrel 80 includes a main shaft 92 which will fit through the rivet opening 86, and extend a substantial distance out of the head 82. At the bottom of mandrel 80 is an enlarged bottom 94 of greater diameter than shaft 92 and having a top shaft 96 adapted to push upward and outward against the bottoms of weakened sections 88. The mandrel shaft 92 has a relatively small diameter neck 98 just above the enlarged bottom 94, which is designed to break when the mandrel top shaft 96 has pushed weakened sections 88 completely upward and outward.

In the preferred form of the invention, the mandrel includes a drill point 100 on the bottom face of the enlarged bottom 94, for use with a special rivet gun adapted to rotate the rivet, to be described further below.

In FIG. 7, a rivet 50 is being held and affixed by a rivet gun 102, a bottom portion of the gun being shown. Gun 102 includes a hollow anvil 104 permitting a mandrel shaft 92 to extend up into the jawcase 106 disposed within the anvil 104, and be firmly grasped therein by the jaws 108. Jawcase 106 and jaws 108 are axially movable within the hollow anvil whereby mandrel shaft 92 is pulled upwardly, forcing enlarged bottom 94 against weakened sections 88, and head 82 against anvil 104. Further upward movement of rivet 50 is prevented by anvil 104 and consequently further upward movement of mandrel 80 causes weakened sections 88 to bend outward.

Rivet 50 is disposed with its head 82 resting on flange 54 and stem 84 extending through hole 58, of a diameter smaller than head 82, and into a cavity 110 which extends only part way through wallboard 42 with a diameter substantially equal to the diameter of stem 84 and a depth substantially equal to the extent of stem 84 and enlarged bottom 94. In the preferred form of the invention cavity 110 is formed by the drill point 100 on mandrel 80, as described further below.

Cavity 110 is a cylindrical hole which extends through the wallboard paper cover sheet 112 and part way through the relatively frangible set gypsum core 114. The structural integrity and strength of a gypsum wallboard is provided primarily by the strong fibrous cover sheet 112.

When weakened sections 88 are caused to bend outward, by the upward movement of mandrel 80 described further above, the bending weakened sections 88 penetrate the relatively frangible core 114 and firmly grasp core 114, paper 112 and flange 54 between the rivet head 82 and the bent weakened sections 88. Weakened sections 88 are formed of a predetermined axial length which permit outward bending by a mandrel only sufficient to dispose the bent end substantially perpendicular to the rivet axis and which provide sufficient resistance to further upward movement of the mandrel enlarged bottom 94 whereby further upward movement of the mandrel shaft 92 results in the shaft breaking off from the enlarged bottom at the small diameter neck 98. The rivet is then firmly affixed and the gun 102, with a broken mandrel shaft in it, may be removed, and the broken shaft discarded.

FIG. 8 shows the final product of affixed flange 54, held by rivet 50, and a now useless broken off enlarged bottom 94 in the bottom of cavity 110. Wallboards 42, 42 are thus suspended by means completely hidden from view on the underside of ceiling 40.

FIG. 9 shows a complete view of the novel gun 102 wherein rotating means are combined with the basically known form of rivet gun for blind fasteners. The primary containing element of gun 102 is the lower handle 120 which, at the working end, has a hollow cylindrical motor mount 122 extending upwardly, and the hollow cylindrical anvil 104 extending downwardly, and, extending rearwardly, an elongate finger grasping portion 124.

The jawcase 106 is rotatably mounted in anvil 104. A pair of closely spaced annular shoulders 126, 126, near the top of jawcase 106, have the bifurcated end 128 of upper handle 130 extending therebetween. Upper handle 130 is pivotally mounted in lower handle 120, whereby pressing the rearward end 132 of upper handle down, toward the lower handle, causes the bifurcated end 128 to raise jawcase 106, which causes jaws 108 to grasp a mandrel 80 by shaft 92, and move the mandrel 80 upward, riveting the flange 54 to the wallboard 42.

The top surface of jawcase 106 has a ratchet face 134 thereon. Mounted atop the motor mount 122 is a motor 136 from which a shaft 138 extends downward. The bottom surface of shaft 138 has a ratchet face 140 corresponding to the ratchet face 134. A coil spring 142 normally urges shaft 138 away from jawcase 106. A drive lever 144 is mounted to move shaft 138 downward, engaged ratchet faces 134 and 140, and rotating jawcase 106.

By the provision of means for rotating jawcase 106, the mandrel 80 having a drill point 100 may be used to form cavity 110, and immediately, on completion of forming of cavity 110, rivet 50 is bent and affixed in place, with the same tool, gun 102, thus reducing the labor required and lessening the probability of errors in the overall process.

Having completed a detailed disclosure of the preferred embodiments of my invention so that those skilled in the art may practice the same, I contemplate that variations may be made without departing from the essence of the invention.

Claims

I claim:

1. In combination, a paper-covered gypsum wallboard comprising a relatively crushable set gypsum interior and a relatively strong paper exterior and a metal fastener affixed thereto, said fastener affixing thereto means for mounting said wallboard, the back face of said wallboard having a hole of a predetermined size in the said paper exterior, said fastener having a portion disposed in said hole and a bent second portion disposed entirely within said interior, said bent second portion having a dimension which prevents withdrawal of said second portion through said hole, said interior having crushed set gypsum adjacent said bent section portion, said fastener having no visible elements at other surfaces of said product than at said hole, said interior also having disposed therewithin a broken-off-mandrel enlarged-bottom having a drill-point on the bottom face thereof.

2. The combination of claim 1 wherein said fastener has an enlarged head portion and wherein at least part of said interior crushed portions are disposed between at least part of said bent second portion and at least part of said head portion.