Drywall fastener

Abstract

A drive-in expansion fastener is provided having a generally cylindrical, hollow body with a tapered end formed from an angular truncation of the body. The body is reinforced by at least one longitudinal rib so as to permit drive-in penetration from the tapered end even if the fastener is formed from plastic materials. The fastener is retained within the wall by at least one pair of hinged flanges which expand or move circumferentially apart in response to the threaded insertion of an ordinary screw within the hollow portion of the body. That screw engages an inclined surface within the body to cam the flanges outwardly. The flanges engage the back surface of the wall while a longitudinally slit portion split length of the body expands within the hole created by drive-in penetration.

Description

preferably extends along longitudinal axis 24. As shown, body portion 22 is hollow and is formed with passageway 26 extending from one end to the other. Tapered portion 28 is formed at one end of body portion 22, and base portion 30 is formed at the other end. Flanged portion 32, which serves to retain fastener 20 within the wall, is located between tapered portion 28 and base portion 30.

Tapered portion 28 is preferrably preferably created as an angular truncation of body portion 22. In visual effect, this truncation creates a slice or cut across body portion 22 at a slight angle A with respect to longitudinal axis 24. As shown, the truncation exposes passageway 26. Thus, in some respects tapered portion 28 resembles the tip of a hypodermic needle. Typically, angle A is less than 45 degrees. The specific angle used according to teachings of the present invention will depend upon the composition, density and thickness of the wall and the dimensions of fastener 20. Angle A is selected so as to facilitate a clean and gradual cut through the wall. A gradual cut is preferred so that substantially all the wall debris can be received within fastener 20 when penetrating the wall. As shown, with ordinary drywall boards and an initial passageway opening of approximately 0.17 inch (0.43 cm) in diameter, angle A is between 5 degrees and 10 degrees.

The wall debris is received during penetration in open portion 34 of passageway 26. In certain embodiments, the configuration of fastener 20 can exert compression stress on the wall as it is penetrating, but this stress is minimized by accumulating debris within fastener 20. In this manner, blow outs are avoided since the fastener does not simply plow through the wall. At the same time, passageway 26 includes a reduced diameter portion 36 which prevents that debris from interfering with expansion adjustment by a threaded screw or other retention element.

To reinforce body portion 22 and facilitate drive-in of fastener 20 when formed from plastic materials, longitudinal rib 38 is provided from base portion 30 to the end of tapered portion 28. Rib 38 is, for example, integrally molded with body portion 22 and tapers to decrease in thickness and/or width from base portion 30 to tapered portion 28.

Tip end 40 of tapered portion 28 provides initial cutting penetration for fastener 20. As shown, tip end 40 has a flat, vertical end wall of height T, that height corresponding to the radial wall thickness of cylindrical body portion 22. On the other hand, as shown in FIGS. 2 and 3, tip end 40 includes a horizontal point of minimal width.

To further facilitate penetration, tapered portion 28 is preferably provided with cutting edges 42 on body portion 22. For example, fastener 20 includes an interior surface 44 lining passageway 26 and an exterior surface 48. Interior surface 44 can be provided with cutting edge 42 at its uppermost portion when the angular truncation of body portion 22 leaves a narrow, flat surface 46 across tapered portion 28 between interior surface 44 and exterior surface 48. Flat surface 46 can also be tapered toward tip end 40 as shown at 50 to reduce wall stress even more during initial penetration.

Base portion 30 is provided with a circumferential, radially extending shoulder or flange 52 to support the drive-in load (as, for example, caused by hammering) on fastener 20 during wall penetration. This flange is preferably relatively thin so as to minimize outward projection from the wall surface when the fastener is fully mounted. Flange 52 also serves as a stop or limit to the penetration of the wall by fastener 20 and as a stop or limit to the extent of insertion of the retention element. Radial ribs or flanges 54 are provided on body portion 22 and, for example, extend from flange 52 along longitudinal axis 24 toward tip end 40. Flanges 54 serve to stiffen flange 52 and assist in supporting drive-in load. Flanges 54 are also typically much shorter than rib 38 and, in combination with rib 38, serve to prevent rotation of the fastener with respect to the wall by slightly penetrating and engaging the wall when the fastener is fully in place. Base portion 30 is also provided with indicia 56 on its end face for indicating the angular orientation of fastener 20 about axis 24. It has been found that greater loads can typically be supported at some orientations of fastener 20 than at other positions.

Body portion 22 includes a split length 58 extending from base portion 30 to tapered portion 28. This split is, for example, longitudinally aligned and divides flange 52 and flange portion 32. Split length 58 permits expansion of body portion 22 to establish retention of the fastener within the wall. This expansion can be caused by insertion of a retention element 60 into passageway 26.

Flange portion 32 includes at least one pair of circumferentially expandable and radially displaceable elements to retain the fastener by engaging the back surface of the wall and/or enlarging the fastener such that it cannot be pulled back toward the front surface of the wall. As shown, three such pairs 62, 64, and 66 are provided. Each pair comprises two opposing retaining arms separated by split length 58. Each retaining arm includes a body element 68 and a flange element 70. These pairs are spaced apart along body portion 22 and are separated by lateral slices 72 in the body portion such that each pair is separately expandable or circumferentially and radially displaceable. Flange elements 70 project radially outward from and, as shown, longitudinally along body portion 22. Prior to expansion, elements 68 are generally continuous with body portion 22 and enclose a portion of passageway 26.

Flange portion 32 is longitudinally spaced apart from shoulder flange 52 by a distance approximately equal to the wall thickness such that shoulder flange 52 and flange elements 70 bound that wall on either side when fastener 20 fully penetrates the wall. In preferred embodiments of the present invention, various different wall thicknesses can be accommodated with the same fastener by specific dispositions of shoulder flange 52, flange elements 70 and slices 72. For example, the distance toward tip end 40 from shoulder flange 52 to first slice 72' would be 3/8" (0.95 cm), from shoulder flange 52 to second slice 72" would be 1/2" (1.27 cm), and from shoulder flange 52 to third slice 72"' would be 5/8" (1.58 cm). That arrangement would permit fastener 20 to be used with drywall boards of 3/8, 1/2" or 5/8" thickness. The width of slices 72 permits room for accommodating variations in wall thickness such as that caused by paint and/or wallpaper. Thus, expansion of flange portion 32 would not scrape material off of the back surface of the wall and thereby weaken the wall.

In the embodiment illustrated in FIG. 2, the wall thickness is equal to or just less than the distance between shoulder flange 52 and first slice 72'. In other applications if the wall thickness is greater, flange pairs 64 and/or 66 may not fully emerge from the hole created in the wall by penetration of the fastener. However, adequate retention of the fastener is available with at least one flange pair which emerges and is expandable along the back side of the wall. In applications where fastener 20 supports only minimal loads and/or expansion within the wall is permissible, adequate retention is available even if no flange pair emerges from the wall.

Flange elements 70 of flange pair 62 are provided with leading edges 74 which are formed so as to cut through the wall as fastener 20 is inserted. For example, leading edge 74 can be inclined approximately 45° with respect to axis 24 in both the horizontal and vertical planes. Once this cut is made the flange elements 70 of flange pairs 64 and 66 can readily follow through. In some embodiments, penetration can also be facilitated by providing tapered upper portions 75 on flange elements 70.

Expansion of flange portion 32 is accomplished through the use of reduced diameter portion 36 in passageway 26. Portion 36 includes a tapered or inclined face 76 open towards base portion 30. Retention element 60, for example, a threaded screw, is inserted within passageway 26 from the opening in base portion 30. Face 76 serves as a cam surface or ramp for initial adjustment engagement with the leading edges of retention element 60. As shown, split length 58 penetrates to reduced diameter portion 36. In addition, longitudinally extending slots 78 are provided along passageway 26 through portion 36. Preferably, slots 78 are coplanar with axis 24 and approximately level with the lowermost portions of slices 72. At the same time, slices 72 preferably extend approximately halfway through body portion 22. Thus, slots 78 can positively and uniformly locate the hinge base for each body element 68 to control the extent and manner of adjustment expansion.

In adjustment expansion for the arrangement of FIG. 2, retention element 60 slides over face 76 and forces each element of flange pair 66 radially outwardly and circumferentially apart. As retention element 60 continues in passageway 26 toward end tip 40, each element of flange pair 64 and then flange pair 62 is forced apart. The expansion of each of these flange pair elements is pivotal with respect to body portion 22 at slots 78 and enlarges the effective circumference of this portion of fastener 20. In certain embodiments, insertion of a sufficiently large retention element will also cause radial expansion of body portion 22 between flange portion 32 and base portion 30 within the wall to snugly embrace the wall material. Expansion of fastener 20 within the wall is also available where, for example, the wall thickness is sufficiently large that one or more flange pairs remain within the wall. In such circumstances the flange pairs can tend to expand toward the back surface of the wall to prevent withdrawal of fastener 20 toward the front surface of the wall. In this manner, retaining fastener 20 within the wall also secures the retention element to the wall.

Using a self lubricating and relatively inexpensive material such as Rynite SST35 to form fastener 20 and/or passageway 26 can significantly reduce the torque necessary to use threaded screws for adjustment expansion. Providing passageway 26 with a large diameter permits several different sized screws to be used as retention elements since adjustment need only result from engagement with reduced diameter portion 36. With radial expansion and circumferential expansion displacement, only minimal opening of the flange pair elements is needed to provide secure retention of the fastener.

It has been found that fastener 20 has greater load bearing capacity when slit split length 58 is at the top of body portion 22 and rib 38 is at the bottom such that the flange pairs spread apart above the lateral midline created by the plane of slits 78 and axis 24. This load-bearing capacity can be sufficiently large so as to enable fastener 20 to be used in ceiling applications.

Although the present invention has been described above in detail, the same is by way of illustration and example only and is not to be taken as a limitation on the present invention. The scope and content of the present invention are defined only by the terms of the claims appended hereto.

Claims

1. An expansion fastener capable of being directly hammered, punched or screwed into a drywall board for securing a retaining member, comprising:

a generally cylindrical, longitudinally extending hollow body portion having a tip at one end for penetrating the drywall board and a base portion at the other end with a passageway extending therethrough between said tip end and base portion;

said body portion including a longitudinally extending tapered portion at one end thereof extending from the tip end towards the base portion for effecting a clean and gradual cut through the drywall board;

said body portion including a flange portion which expands circumferentially extending in the longitudinal direction of the body portion, said flange portion expands radially outwardly in response to insertion of said retaining member into said body portion and at least a portion of said flange portion is displaced circumferentially; and

said flange portion includes means facing toward said tip end for cutting through the drywall board as the fastener is inserted; and

prior to said expansion of said flange portion, said flange portion projects radially outward from said body portion.

2. The fastener according to claim 1 wherein said tapered portion is formed by an angular truncation of one end of said body portion extending longitudinally from said tip end toward said base portion.

3. The fastener according to claim 1 wherein said tapered portion includes a cavity for receiving debris caused by insertion of said fastener into a said drywall board member.

4. The fastener according to claim 3 wherein said body portion includes a generally longitudinal passageway therethrough and said cavity includes a portion of said passageway.

5. The fastener according to claim 4 wherein said passageway includes a longitudinal restriction having an inclined face for initial engagement with said retaining member.

6. The fastener according to claim 1 wherein said flange portion extends longitudinally with said body

portion.7. The fastener according to claim 1 wherein said body portion includes an exterior surface, and further including a tapered longitudinal rib for reinforcing said body portion, said rib being disposed adjacent

said exterior surface and radially extending from said body portion. 8. The fastener according to claim 1 wherein said body portion includes an exterior surface, and further including means connected to said exterior

surface for preventing rotation of said body portion. 9. An expansion fastener capable of being directly hammered, punched or screwed into a drywall board for securing a retention member to a said board, comprising:

a generally cylindrical, longitudinally extending hollow body portion having a tip end at one end for penetrating the drywall board and a base portion at the other end and a substantially longitudinal passageway therethrough;

said body portion including a tapered means extending from the tip end towards the base portion for facilitating penetration of said board by said body portion;

said tapered means being formed by an angular truncation of one end of said body portion extending from said tip end towards said base portion;

said body portion including a retaining portion for preventing removal of said body portion from said board;

said retaining portion including a flange member portion radially projecting outwardly from said body portion and extending longitudinally therewith; and said retaining flange portion expands circumferentially radially in response to insertion of said retention member into said passageway and moves circumferentially; and

said flange portion includes means facing towards said tip end for cutting

through the drywall board as the fastener is inserted. 10. The fastener according to claim 9 wherein said angular truncation exposes a portion of said passageway to receive board debris caused by said

penetration of said board by said body portion. 11. The fastener according to claim 9 wherein said retaining flange portion expands radially and moves circumferentially adjacent and exterior of said board in said response to insertion of said retention

member into said passageway. 12. The fastener according to claim 9 wherein said tapered means includes internal and external surfaces and board-cutting edges at said internal surface to facilitate said

penetration of said board. 13. The fastener according to claim 9 wherein the angle of said truncation with respect to said body portion is established for a particular board composition such that drive-in penetration of said board by said body portion does not result in

formation of a blow out region on said board. 14. The fastener according to claim 9 wherein the angle of said truncation with respect to the

longitudinal axis of said body portion is less than 45 degrees. 15. The fastener according to claim 9 wherein said board comprises drywall material and the angle of said truncation with respect to the

longitudinal axis of said body portion is less than 10 degrees. 16. The fastener according to claim 9 wherein said body base portion includes a base shoulder opposite said tapered means, said shoulder including second flange means for preventing rotation of

said body portion. 17. The fastener according to claim 16 wherein said second flange means includes a plurality of radially projecting elements which extend longitudinally along said body portion from said shoulder.

The fastener according to claim 9 further including expansion means disposed within said passageway for moving said retaining flange portion in response to said insertion of said

retention member into said passageway. 19. The fastener according to claim 18 wherein said expansion means is formed as a longitudinal restriction in said passageway having a ramped end for engaging said retention member.

The fastener according to claim 19 wherein said expansion means includes longitudinal slot means for defining the a

base of said retaining flange portion. 21. The fastener according to claim 20 wherein said means of said flange member portion includes a forward cutting edge having an angle of inclination at least as steep as the angle of said truncation with respect to the longitudinal axis of said body

portion. 22. The fastener according to claim 9 wherein said flange member portion includes at least one pair of initially adjacent, parallel projection body and flange elements before being expanded which move radially outwardly and circumferentially apart in response

to said insertion of said retention member into said passageway. 23. The fastener according to claim 22 wherein said flange member portion includes a plurality of pairs of projection said body and flange elements spaced apart longitudinally

along said body portion. 24. The fastener according to claim 23 wherein said plurality of pairs of projection body and flange elements are sequentially moved apart by said insertion of said

retention member into said passageway. 25. The fastener according to claim 24 wherein said body portion includes a longitudinal split, said split being aligned between said pairs of projection body and flange elements and providing means for said body portion to expand circumferentially in response to said insertion of said retention member into said passageway wherein as said body portion expands radially said body and flange elements of at least one of said pairs of

body and flange elements move circumferentially apart. 26. The fastener according to claim 9 wherein said body portion is formed from a

moldable, plastic material. 27. A drive-in expansion fastener capable of being directly hammered, punched or screwed into a drywall or plaster board for securing a retention element to a said drywall or plaster board, comprising:

a generally cylindrical, longitudinally extending hollow body portion having a tip end at one end for penetrating the drywall or plaster board and a base portion at the other end with a longitudinal passageway extending therethrough between said tip end and said base portion;

said body portion including a tapered means extending longitudinally and having board-cutting edges for facilitating drive-in penetration of said board by said body portion;

said tapered means being formed as an angular truncation of one said tip end of said body portion;

the angle of said truncation with respect to said body portion being established such that penetration of said board by said body portion does not result in formation of a blow out region on said board;

a base portion formed on said body portion at an end opposite said tapered means;

said base portion including a radially outwardly extending shoulder;

said body portion including a retaining means longitudinally spaced apart from said shoulder for preventing removal of said body portion from said board;

said retaining means including a flange portion radially projecting outwardly from said body portion; and

said flange portion includes means facing toward said tip end for cutting through the board as the fastener is inserted, and

an expansion means disposed within said passageway for circumferentially radially expanding said flange portion outwardly with respect to said body portion in response to insertion of said retention element into said passageway and for

circumferentially displacing said flange portion. 28. The fastener according to claim 27 wherein said fastener is molded from a

nylon material. 29. The fastener according to claim 27 wherein said retention element is threaded for rotatable insertion into said passageway

and said passageway is formed from a self-lubricating material. 30. The fastener according to claim 27 wherein said passageway is longitudinally exposed by said angular truncation such that board material is received therein during said drive-in penetration of said board by said body

portion. 31. The fastener according to claim 30 wherein said retaining means flange portion includes a plurality of pairs of spaced apart hinged members, at least one of said pairs including said flanged portion being circumferentially displaceable apart as

said flange portion is radially expanded. 32. A drive-in expansion fastener capable of being directly hammered, punched or screwed into a drywall or plaster board for securing a retention element to a said drywall or plaster board, comprising:

a generally cylindrical, longitudinally extending hollow body portion having a tip end at one end for penetrating the drywall or plaster board and a base portion at the other end and with a longitudinal passageway extending therethrough;

said body portion including a longitudinally extending tapered means having board-cutting edges for facilitating drive-in penetration of said board by said body portion;

said tapered means being formed as an angular truncation of one said tip end of said body portion;

the angle of said truncation with respect to said body portion being established such that penetration of said board by said body portion does not result in formation of a blow out region on said board;

said passageway is longitudinally exposed by said angular truncation such that board material is received therein during said drive-in penetration of said board by said body portion;

a base portion formed on said body portion at an end opposite said tapered means;

said base portion including a radially outwardly extending shoulder;

said body portion including a retaining means longitudinally spaced apart from said shoulder for preventing removal of said body portion from said board;

said retaining means includes a plurality of pairs of spaced apart hinged members, at least one of said pairs including a flange portion radially projecting from said body portion;

the hinge base of said hinged members is formed by a longitudinal slits split length in said body portion; and

an expansion means disposed within said passageway for moving said flange portion circumferentially and radially outwardly with respect to the circumference of said body portion in response to insertion

of said retention element into said passageway. 33. The fastener according to claim 32 wherein said body base portion includes a circumferential base shoulder for receiving the impact of means for

causing said drive-in penetration of said board by said body portion. 34. The fastener according to claim 33 wherein said shoulder includes visible indicia thereon for indicating the orientation of said fastener

within said board. 35. The fastener according to claim 33 wherein said shoulder includes longitudinally extending projections for preventing rotation of said body portion with respect to said board after said

drive-in penetration and during insertion of said retention element. 36. An expansion fastener capable of being directly hammered, punched or screwed into a drywall board for securing a retaining member thereto, comprising:

a generally cylindrical, longitudinally extending hollow body portion having a tip end at one end for penetrating the drywall board and a base portion at the other end with a passageway extending therethrough between said tip and and base portion;

said body portion including a longitudinally extending tapered portion at one end thereof extending from the tip end towards the base portion for effecting a clean and gradual cut through the drywall board;

said body portion including a flange portion which expands radially and is displaced circumferentially in response to insertion of said retaining member into said body portion;

said tapered portion includes a cavity for receiving debris caused by insertion of said fastener into a said drywall board member;

said body portion includes a generally longitudinal passageway therethrough;

said cavity includes a portion of said passageway; and

said passageway includes a longitudinal restriction having an inclined face for initial engagement with said retaining member;

said flange portion includes means facing towards said tip end for cutting through the drywall board as the fastener is inserted; and

prior to said expansion of said flange portion, said flange portion

projects radially outwardly from said body portion. 37. The fastener according to claim 36 wherein said tapered portion is formed by

an angular truncation of one end of said body portion. 38. The fastener according to claim 36 wherein said body portion includes an exterior surface, and further including a tapered longitudinal rib for reinforcing said body portion, said rib being disposed adjacent said exterior surface and radially extending outwardly from said body portion.

The fastener according to claim 36 wherein said body portion includes an exterior surface, and further including means connected to said exterior surface adjacent said base portion for preventing rotation of said body portion.