Patent Application
20070031186
The present invention relates self-clinching fasteners and more specifically to cost effective fasteners that can only be clocked into a thin sheet panel one way.
Over the previous decades self-clinching fasteners have displayed a round cross section. A round cross section has permitted the self-clinching fastener itself to be clocked into a sheet panel in an infinite number of orientations.
Recently, several self-clinching fasteners have been developed to be clocked into a sheet panel in four or less possible orientations.
One approach that provides only one possible clocking intended to join two thin sheets at a right angle was disclosed by Winton in U.S. Pat. No. 5,452,978. Winton '978 describes a self-clinching fastener that has a square and/or rectangular base. Winton '978 teaches of a base with a round self-clinching feature coupled with an out-board feature(s) used to prevent the Winton '978 from rotating once self-clinched to a sheet panel.
The disadvantage of this approach is the manufacturing costs to produce Winton '978. The process to produce Winton '978 would involve metal injection molding. The costs associated with such an established process would prevent Winton '978 from gaining any significant market share.
Another approach providing four possible clockings intended to join two sheets at a right angle was disclosed by Winton 5,489,175. Winton '175 teaches of a square self-clinching base that makes use of two parallel features used to self-clinch to a mating sheet panel. As in Winton '978, Winton '175 teaches of a tapped hole used to receive a fastener intended to join two sheets at a right angle. Although not cited in the Winton '175 claims, the drawings of Winton '175 shows a square base.
The disadvantages of Winton '175 are the costs associated with manufacturing coupled by its perceived square base. Because the parallel self-clinching features are perpendicular to an axis of the tapped hole, the manufacturing process for Winton '175 lends itself to the higher costs associated with metal injection molding. Moreover, the square base allows Winton '175 to be installed into a square hole in 4 possible orientations (clockings); thus a minimum of two of the orientations being 90° out from the needed clocking.
Another approach showing two possible clockings intended to join two sheets at a right angle was disclosed by Ross in U.S. Pat. No. 5,810,501. Ross '501 teaches of a rectangular base that self-clinches to a surrounding sheet panel. Ross '501 describes a fastener where the hole intended to receive a threaded fastener is parallel to the two linear self-clinching features. By making the tapped hole parallel to the linear self-clinching features, Ross '501 can be made from an extrusion process, metal injection molding process, or a process known as power metal processing (press metal). The first and last two processes are less costly then the metal injection molding process.
One disadvantage of the Ross '501 invention involves the hardness of the finished part. When fabricating steel parts using the press metal process, the hardness of the finished part is much less then that of cold drawn steel itself. In general, parts manufactured/molded from power metal tend not to be as hard as parts crafted from a bar of cold drawn steel.
When installing self-clinching fasteners in general, it is well known that in order to self-clinch a fastener into a sheet panel, the surrounding sheet panel must be softer than the fastener itself. The process of press metal fabrication can not produce a part hard enough to penetrate some steel panels found in industrial applications today. Nevertheless, the press metal process allows parts to be produced at a reasonable cost and still be hard enough for a limited number of industrial applications.
Another disadvantage of the Ross '501 invention is that for ever configuration needed for market, a separate mold is needed to fabricate that specific size. For the most part, this is the case with an extruded part, metal injected molded part, and parts fabricated from the press metal process.
Another disadvantage of the Ross '501 invention is the needed design symmetry of the fastener for correct installation into a rectangular hole in a sheet panel. Therefore, the Ross '501 invention must be symmetrical in order for it not to be installed backwards into a rectangular hole.
Thus far the disadvantages of the above inventions involve:
As it turns out there is a self-clinching prior art that takes on all of the above disadvantages (less the symmetry objection) and is not used as a right angle bracket. Bentrim in U.S. Pat. No. D461,705S disclosed a self-clinching cable hook. Bentrim '705S shows a rectangular self-clinching base with a non symmetrical hook built onto the rectangular base. In order to use the Bentrim '705S hook effectively, it must be clocked into a sheet panel via the correct orientation. As can be seen from the marketing literature from Penn Fastening Systems (see PEM Bulletin), Bentrim '705S has an indentation mark on the far side surface to direct the clocking of the fastener during installation into a sheet panel.
The Disadvantage of Bentrim '705S lies in the rectangular base coupled with the non-symmetrical design; it can be installed two ways. However, only one way is most often desired by an end user. Another disadvantage of Bentrim '705S is the cost of the manufacturing process; cast power metal. Made from power metal as stated in the PEM bulletin, the limited hardness of the inventive fastener also limits the number of applications.
Clearly, a common thread of disadvantages exists between the two applications; that being the right-angle bracket and the cable hook.
Accordingly, several objects and advantages of my invention are:
(a) to produce a common base that overcomes the disadvantages as stated above; the base when combined with specific added features will serve as an intended application such as a right-angle bracket and/or a cable hook;
(b) to reduce the costs of manufacturing by producing an application on a screw machine whereby various steels with a specific hardness greater than that produced with the press metal process can be formed; and
(c) to produce a non symmetrical fastener that can only be installed one way from any given side of a sheet panel.
Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings.
From
A D shaped cross section of body 39 is seen when viewing base 10 along axis 40 in a direction towards extended land 12.
The diameter of body 39 is greater than the diameter of undercut groove 13 yet smaller than the diameter of extended land 12.
Undercut groove 13 is shown as a D shape cross section. However, if the diameter of undercut groove 13 were smaller then that depicted, undercut groove 13 might not display a D shape cross section and therefore would be completely circular in cross section. Nevertheless, the diameter of undercut groove 13 will always be smaller then the diameter of body 39.
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In operation, from
Inventive bracket 11 will be installed completely when surface 23 is flush with surface 18.
The self-clinching process is describe in most of the prior art cited and is considered will known by those schooled in the art of self-clinching fasteners.
Once inventive bracket 11 is installed, mating panel 24 can be joined to mating surface 14. Screw 25 can then be used to secure panel 20 to inventive application 11 thru hole 27.
In operation, from
From the discussion above it is obvious that inventive base 10 can be used to support numerous applications. For example, base 10 could be used to support an application crafted from nylon as described in
