GB2060112A

GB2060112A - Threaded Fasteners having a Sealing Cover

Info

Publication number: GB2060112A
Application number: GB8033036A
Authority: GB
Original assignee: Illinois Tool Works Inc
Current assignee: Illinois Tool Works Inc
Priority date: 1979-10-12
Filing date: 1980-10-13
Publication date: 1981-04-29
Also published as: IT1133835B; JPS5663112A; SE8006648L; BR8006529A; IT8025211A0; NL8005592A; ES265661U; DE3038433A1; CA1142780A

Abstract

A screw-threaded fastener 10 includes a head 12 having top surface 32 contoured (at 34) for interlocking engagement with a driver, a threaded shank 14 extending from the clamping surface 36 and a moisture-impervious cover 16 which overlies the head portion 12 and extends axially away from the clamping surface 36 to form a flange 42 for sealing the fastener 10 to a workpiece surface into which the fastener is driven. The flange 42 is inwardly deformable upon contacting the work piece surface so as to deflect work piece fragments, produced as the fastener is driven into the work piece, away from the seal between the flange 42 and the work piece surface to preclude the fragments from interfering with the seal. A cavity 44 receives the work piece fragments as the flange is deformed. <IMAGE>

Description

SPECIFICATION Threaded Fasteners Having a Sealing Chip Skirt Background of the Invention The present invention is generally directed to an improved fastener and more particularly to an improved threaded fastener which establishes a seal between the fastener and a work piece surface into which it is driven.

There are many applications where fasteners must be threadingly received by work pieces.

Thread tapping and thread forming fasteners are very popular for this purpose because the work piece openings to receive the fasteners need not be pre-tapped with internal threads. Also, drilling screws are popular because they include their own drill tip and therefore do not even require a pre-drilled hole.

Screws or fasteners of this type, when driven into a work piece, scrape paint or other corrosion resistant coatings from the work piece surface immediately adjacent or around the connection between the fastener and the work piece. The exposed bare work piece surface areas are thus subject to corrosion or rust unless means are provided to seal the connection between the work piece opening surrounding areas and the fastener.

Further, work piece fragments are produced by thread tapping and drilling screws. These fragments can interfere with the aforementioned seal unless they are displaced from the seal area.

These fragments can further be harmful to or damage moving parts or electrical components associated with or near to the fastener connection.

Prior art fasteners have therefore been proposed and used which include a moisture impervious cover about the head of the fastener which are arranged to enclose and seal the exposed work piece surface areas. However, fasteners of this type in the prior art have not been structured to both provide an effective seal and cope with the work piece fragments. Hence, moisture sealing fasteners of the prior art suffer from the collection of work piece fragments in the seal area which eventually, if not immediately, destroy the intended seal of the connection between the fastener and the work piece. Further, those fragments which are not lodged in the moisture sealing area are rendered free for displacement to moving or electrical components associated with or near to the fastener connection. As previously mentioned, these fragments can cause harm or damage to such components.

It is therefore a general object of the present invention to provide a new and improved moisture sealing fastener.

It is a more specific object of the present invention to provide a moisture sealing threaded fastener which provides a complete and effective moisture sealing notwithstanding the production of work piece fragments as the fastener is driven into a work piece.

It is a still further object of the present invention to provide such a fastener which deflects work piece fragments away from the seal area and further traps the fragments to preclude their free displacement.

The invention therefore provides a fastener comprising a head portion having a clamping under surface and an upper surface contoured for interlocking engagement with a driver, a shank portion extending from the clamping surface having a transverse dimension smaller than the head portion and a thread, and seal means overlying the head portion and axially extending from the clamping surface for sealing the connection between the fastener and a work piece surface into which the fastener is threadingly received. The axial extension comprises a flange which is inwardly deformable upon contacting the work piece surface for deflecting work piece fragments away from the seal between the flange and the work piece surface to preclude the fragments from interfering with the seal.

Brief Description of the Drawings The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with further objects and advantages thereof, may best be understood by making reference to the following description taken in conjunction with the accompanying drawings, in the several figures of which like reference numerals identify identical elements, and wherein: Fig. 1 is a side view, partly in cross-section, of a fastener embodying the present invention; Fig. 2 is a top plan view of the fastener of Fig.

1;and Fig. 3 is a side view, partly in cross-section, on, illustrating the fastener of Fig. 1 after being fully driven into a work piece.

Description of the Preferred Embodiment Referring now to Figs. 1 and 2, the fastener 10 embodying the present invention is of a type commonly referred to as a drilling screw.

However, it will be apparent hereinafter that the present invention may also be advantageously employed in thread tapping or thread forming screws as well or in any fastener for that matter wherein a seal between the fastener and a work piece is desired. The screw 10 generally includes a head portion 12, a shank portion 14, and a moisture impervious cover 1 6 overlying the head portion 12. The shank portion 14 of the fastener or screw 10 includes a drill point 18 at the end of shank 14 opposite the head portion 12. The drill point 1 8 is fluted and includes a pair of segments, one of which is shown at 20, removed from the circular cross-section of the shank and leaving land portions 22 remaining therebetween.The drill point 18 has an effective transverse width substantially equal to the transverse width of the shank roots 24 and of lesser dimension than the effective transverse dimension of the thread crests 26. The thread of shank portion 14 defined by the roots 24 and crests 26 extends helically from the drill point 18 to the head portion 12.

The drill point 1 8 terminates in a pair of cutting edges, one of which is shown at 28, which drill into the work to create an opening in the work piece. As the screw 10 is driven, the threads 30 defined by the roots 24 and crests 26 form a cooperating thread in the drilled work piece opening and permit the screw to be driven home.

The head portion 12 includes an upper surface 32 which is contoured to form a tool receiving recess 34 to afford interlocking engagement of the head portion 12 with a driver (not shown).

The head portion 12 further includes an under surface 36 including a raised surface portion 38 having a generally square outer periphery and an under cut or relief surface portion 40 which extends from the perimeter of the raised portion 38 out to the periphery of the under surface 36.

The moisture impervious cover 16 completely overlies the upper surface 32 of the head portion 12 and is contoured in correspondence with the upper surface to further define the tool receiving recess 34 and rotationally fix the cover 1 6 with respect to the head 12. The cover 1 6 axially extends from the clamping under surface 36 of the head portion 12 toward the shank portion 14.

As a result, an annular flange or seal ring 42 is formed. The annular flange 42 is coaxially disposed with respect to the shank portion 14 and is of greater diameter dimension than the transverse dimension of the shank portion. As a result, a cavity 44 is formed by the annular flange 42 and the clamping surface 36 of the head portion 12.

As may be further noted in Fig. 1 the annular flange 42 terminates in a narrow edge 46 having a curved surface portion 48. Preferably, the moisture impervious covering 16 is formed from a resilient material so that, with the relatively narrow edge portion 46 and its outer curved surface 48, the annular flange 42 is rendered inwardly deformable upon contacting the surface of the work piece into which the fastener or screw 10 is driven.

As has been previously noted, when a fastener such as fastener or screw 10 of Fig. 1 is driven into an opening of a work piece, outer surface paint of the work piece around the opening is scraped by the fastener. Further, in the case of drilling screws and thread tapping screws, work piece fragments are produced. As can be appreciated from the foregoing, as the fastener 10 of Fig. 1 is driven into the work piece, and as the annular flange 42 contacts the work piece surface, the annular flange 42 will inwardly deform (as best seen in Fig. 3) to create a seal between the fastener and the work piece. Also, as the flange inwardly deforms, it will deflect work piece fragments into the cavity or pocket 44 and away from the sealing area established by the annular flange 42.

Referring more specifically now to Fig. 3, it illustrates the fastener 10 after being fully driven into a work piece 50. As can be noted in Fig. 3, the annular flange 42 has been inwardly deformed and received by the relief surface portion 40 of the clamping surface 36. It may be further noted in Fig. 3 that as the annular flange 42 was inwardly deformed, it deflected work piece fragments or paint chips into the cavity 44 (Fig. 1) and eventually up against the relief surface portion 40 and the periphery of the surface portion 38. As a result, the work piece fragments and paint chips 52 were deflected away from the seal area between the annular flange 42 and the surface 54 of the work piece 50.

As can be further appreciated from the foregoing, the fragments 52 are also confined within the fastener 10 to prevent their free displacement into moving parts or electrical components associated with the connection between the fastener 10 and the work piece 50.

As a result, a complete and effective seal is provided between the fastener 10 and the work piece 50 which is free from work piece fragments or paint chips which could immediately or eventually destroy the intended seal of the connection between the fastener and the work piece.

While a particular embodiment of the present invention has been shown and described, modifications may be made, and it is therefore intended to cover in the appended claims all such changes and modifications which fall within the true scope of the invention.

Claims

1. A fastener comprising: a head portion having a clamping under surface and an upper surface contoured for interlocking engagement with a driver; a shank portion extending from said clamping surface having a transverse dimension smaller than said head portion and a thread; and seal means overlying said head portion and axially extending from said clamping surface for sealing the connection between said fastener and a work piece surface into which said fastener is threadingly received.

2. A fastener as defined in claim 1 wherein said seal means axial extension comprises a deformable flange for sealing the connection between said fastener and the work piece.

3. A fastener as defined in claim 2 wherein said flange is inwardly deformable upon contacting the work piece surface for deflecting work piece fragments away from the seal between said flange and the work piece surface to preclude the fragments from interfering with said seal.

4. A fastener as defined in claim 3 wherein said flange and said clamping surface define a cavity for receiving work piece fragments as said flange is deformed, said cavity being separated from the sealed connection by said flange.

5. A fastener as defined in claim 4 wherein said flange terminates in a narrow edge for assisting in the deforming of said flange and the deflection of the fragments.

6. A fastener as defined in claim 5 wherein said clamping surface includes a relief surface portion for receiving said flange as it inwardly deforms.

7. A fastener as defined in claim 6 wherein said shank portion transverse dimension is circular, and wherein said flange is annular and coaxially disposed with respect to said shank portion.

8. A fastener comprising; a head having a clamping under surface and a top surface adapted for interlocking engagement with a driver; a shank portion extending from said clamping surface and including a thread defining a transverse dimension smaller than said head portion; and seal means carried by said head portion including a sealing ring for sealing the connection between said clamping surface and the surface of a work piece into which said fastener is threaded and being inwardly deformable upon establishing said seal for deflecting fragments of the work piece resulting from the threaded engagement of said thread with the work piece away from said seal.

9. A fastener as defined in claim 8 wherein said sealing ring defines a pocket with said clamping surface for trapping work piece fragments.

10. A fastener as defined in claim 9 wherein said seal means completely covers said head portion top surface.

11. A fastener as defined in claim 1 or claim 8, substantially as described with reference to the accompanying drawings.