MXPA03005501A - Floating captivated wrenchable nut. - Google Patents

Abstract

A two-piece fastening system utilizes separate parts, a nut and a retainer, which are securely united from opposite sides of the captivating element such as a sheet or panel. The nut body which has an axial threaded bore includes an integral collar located on one side of the nut having an outside diameter less than the outside diameter of the nut body. A tubular shank unitary with the nut body extends coaxially from the collar, the outside diameter of the shank being less than the outside diameter of the collar. The shank includes an expandable portion near its end which is deformable to provide attachment to the second part, a retainer, which has a bore that receives the expandable portion of the shank. The retainer boar includes an inside wall against which the expandable portion of the shank is forced to achieve attachment of the parts. The width of the retainer is preferably greater than the length of the shank so that once attached, the end of the shank is below the end face of t he retainer. The inner face of the retainer abuts an annular end of the collar so that forces between the retainer and a threadably attached par t cannot be transferred through the deformable portion of the shank. The retainer may be composed of a harder material or one that provides reduced friction to enhance its capability as a rotational, load-bearing surface. The two parts are assembled to the panel by inserting the tubular shank of t he nut through the panel aperture, installing the retainer over the shank from the opposite side of the panel, and then deforming the shank against the inner wall of the retainer.

Description

NUT TO ACTUATE WITH KEY, CAPTURED AND FLOATING FIELD OF THE INVENTION The present invention relates to threaded fasteners and more particularly to fasteners that are captively connected to a sheet or panel. More specifically, it relates to a captured nut connected to a panel, by joining two separate elements from opposite sides of the panel. BACKGROUND OF THE INVENTION Fasteners that function as a nut internally threaded are known in the art with the benefit of being captured with an application element such as a sheet or panel. A typical configuration of a fastener captured on a blade is a simple threaded nut with female threads using a hexagonal shaped body to allow rotation by a tool to turn the nut. This fastener is illustrated, for example, in U.S. Pat. No. 6,486,402 to Harger et al., Which describes a loose, detached rivet nut that is rotatably fastened to a strip. The nut is connected to the strip by an arrow or axis of overlap or stacking extending from the back side of the nut. The arrow is first inserted through an opening in the strip and then flared on the opposite side of the strip to a diameter greater than the opening. This provides a loose riveting of the nut that allows it to be rotated while being fastened to the strip. Simple, one-piece fasteners of this type provide the advantages and convenience of capture, however there is problem. The spacing between the capture element such as a sheet or panel and the connected part can not be controlled easily or precisely and many applications have a need because spacing is determined to allow a minimum separation between the components to be joined. In larger applications, stacking of tolerances may also be present as a problem, especially in an environment subject to significant changes in temperature, where a desired spacing may be lost due to relative variations in the size of the pieces by their different coefficients of expansion. A precisely predetermined spacing may also be required where a package is employed between the joined parts. Still another problem is the force limitation of the flare or rivet on the back side of the nut because that portion of the material may be too yielding to counterattack sufficiently high connecting forces against a connected component. Therefore there is a need in the specialty for a catch nut assembly to overcome these problems. COMPENDIUM OF THE INVENTION In order to solve the problems in the art described above, the present invention has been designed. It comprises a two-piece fastening system using separate parts, a nut and a retainer, which securely join from opposite sides of the capture element such as a sheet or panel. The nut body having an axial threaded bore includes an integral collar located on one side of the nut having an outer diameter smaller than the outer diameter of the nut body. A unitary tubular rod with the nut body extends coaxially from the collar, the outer diameter of the rod is less than the outer diameter of the collar. The stem includes an expansion portion near its end that is deformable to provide connection to the retention. The second part, the retainer has a perforation in which the expansion portion of the stem is received. The retainer perforation includes an inner wall against which the expansion portion of the stem is forced to achieve connection of the parts. In the preferred embodiment, the wall of the retainer is frusto-conical and converges in the direction of the body. The width of the retainer preferably is greater than the length of the rod, such that once connected, the end of the rod is below the end face of the retainer. The inner face of the retainer butts to an annular end of the collar, such that forces between the retainer and the threadedly connected part can not be transferred through the deformable portion of the rod. The retainer may be composed of a harder material or one that provides reduced friction to improve its capacity as a load bearing, rotational surface. This two-part nut of the invention is assembled to the panel by inserting the tubular stem of the nut through the panel opening by installing the retainer on the stem, and then deforming the stem against the inner wall of the retainer. As will be more fully described herein, the use of separate parts instead of deforming a single part allows many advantages and a much wider range of design freedom to provide an application with a nut for actuating with internally tapped, captured key. Because the nut shank is installed sub-level in the retainer, the load support against the back side of the fastener is held by the retainer instead of the deformable element of the nut. In this way, connecting forces are transferred more rigidly to the body of the nut, providing a more secure connection of the parts and preventing over-deformation of the rod that can lock the nut to the panel. Also, the present invention allows the separate parts to be made of different materials, each by its desired characteristic. This is highly desirable, since otherwise the deformable element must necessarily be relatively yielding, while a supporting surface is also required to be hard. Another beneficial feature of the invention is that the stem requires only deformation enough to connect to the retainer instead of undergoing expansion to a larger diameter, larger than the mounting opening. Since a lower degree of deformation is required, a harder material can be used and the joint between the parts can be stronger. Furthermore, under high friction conditions between the retainer and the load holder, the separate retainer is capable of rotating on the nut shank, while a unitary part does not. This can prevent damage to both the fastener and the threaded element. As yet another advantage, the connection space between the capture element and structures of the nut can be precisely controlled by the width of the collar that is located between the body of the nut and the retainer. This allows a more tight tolerance of the nut assembly that provides a loose but tightly held nut. More benefit can be achieved by over-sizing of the connection opening in the panel or sheet, to allow the fastener to "float" in order to compensate for misalignment of the corresponding threaded part or the connection opening. The amount of flotation is limited only by the diameters of the retainer and the nut body that are independent of the degree of deformation of the rod. Other objects and advantages of the invention will be readily apparent from the following drawings and description of the preferred embodiment. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially sectioned isometric front top view of the assembly of the invention. Figure 2 is a partially sectioned front view of the invention in an intermediate assembly stage. Figure 3 is a partially sectioned front view of the invention fully assembled. DESCRIPTION OF THE PREFERRED MODALITY Now with reference to Figure 1, the three main components of the assembly of one embodiment of the invention include the nut body 11, the capture element 13 such as a blade or panel and the retainer 15 which is clamped to the stem of the nut body on the opposite side of the panel. The nut body preferably includes internal threads 17 and flat portions for key actuation 19 about its periphery for rotation with a tool. The body of nut further includes an integral collar 12 and a deformable shank 14 extending axially from the collar. The collar has an annular end 16 for engaging the butt confinement surface 23 of the retainer. An elevated area 10 at the base of the nut body provides a shallow separating support of the panel. The panel 13 includes an opening having an edge 21 that can be sized substantially larger than the shank. The retainer 15 includes an axially tapered inner wall 18 which provides a frusto-conical surface converging in the direction of the nut body and further includes a chamfered end face 25. Now with reference to Figure 2, the nut body 11 of the invention is illustrated positioned to connect the panel 13 to the collar 12 and stem 14 which extends through the opening in the panel. The retainer 15 is placed on the opposite side of the panel with the inner wall 18 positioned on the shank 14 and with the butt confinement surface of the retainer disposed against the end of the collar 12 on the joint 22. As will be readily apparent from this view , the width of the collar 12 is greater than that of the panel 13, providing a rigid structural space 20 between the nut assembly and the panel. Now with reference to Figure 3, the same view shown in Figure 2 is illustrated except that the shank 14 has deformed against the inner wall of the retainer 15, thereby attaching the retainer to the nut body and capturing in a secure manner. the nut assembly 11 to the panel 13. As can be seen from this view, there is also a substantial space between the collar of the nut body and the edge of the opening of the panel 13, thereby allowing the nut assembly to move laterally or float, which may be required for threaded coupling of misaligned parts. Also, this figure illustrates that the shank requires only minimal deformation, the larger outer diameter of the shank shank is less than the opening in the panel 13. Also, as further illustrated, the length of the shank 14 is slightly smaller than that of the shank. the width of the retainer, providing a sub-level connection of the retainer to the nut body. This ensures that the deformable portion of the shank does not contact any component that is held by the nut.

In this way, it will be appreciated that the objects of the invention have been achieved by the preferred embodiment described. It should be understood, however, that there may be many other modifications and changes to the present invention, which will be apparent to those skilled in the art from the foregoing description, however, the present invention will be limited only by the following claims and its legal equivalents.

Claims (1)

1. CLAIMS 1. A capture nut assembly for loose connection with a perforated element such as a blade or panel, characterized in that it comprises: a nut body having an axial threaded bore; a collar located on a first side of the nut body, the collar has an outer diameter smaller than the outer diameter of the nut body, - a unitary tubular stem with the nut body and extending coaxially from the first side of the nut body , the shank has an axial bore and an outer diameter smaller than the outer diameter of the collar; a portion of stem expansion; and a retainer having a perforation in which the expansion portion of the stem is received, the perforation includes an inner wall, whereby the retainer is axially clamped to the nut body by the deformation of the stem against the inner wall of the retainer. The capture nut assembly according to claim 1, characterized in that the inner wall of the retainer is frusto-conical and converges in the direction of the nut body. 3. The capture nut assembly according to claim 2, characterized in that in addition the collar includes an annular end face that abuts the retainer abuttingly. 4. The capture nut assembly according to claim 3, characterized in that the length of the rod is less than the width of the retainer. The capture nut assembly according to claim 4, characterized in that the nut body and the retainer are composed of different materials, the retainer is of greater hardness than the nut body. The capture nut assembly according to claim 1, characterized in that the collar is unitary with the nut body. The capture nut assembly according to claim 6, characterized in that the frusto-conical inner wall extends over the entire width of the retainer. The capture nut assembly according to claim 7, characterized in that the retainer is circular. 9. The capture nut assembly according to claim 1, characterized in that the end face of the retainer is chamfered. 10. A part assembly, characterized in that it comprises: a nut assembly comprising: a nut body having an axial threaded bore; a collar located on a first side of the nut body, the collar has an outer diameter less than the outer diameter of the nut body a unitary tubular rod with the nut body and extending coaxially from the first side of the nut body, the rod has an axial bore and an outer diameter smaller than the outer diameter of the collar; a portion of stem expansion; and a retainer having a bore in which the expansion portion of the stem is received, the bore includes an inner wall and the retainer is axially clamped with the nut body by the deformation of the stem against the inner wall of the retainer; and a capture element having an opening in which the shank is received, the edge of the element around the opening disposed between the nut body and the retainer wherein a portion of the collar is located within the opening. 11. The assembly in accordance with the claim 10, characterized in that the inner wall of the retainer is frusto-conical and converges in the direction of the nut body. 12. The assembly according to claim 11, further characterized in that the collar includes an annular end face abutting the retainer. The assembly according to claim 12, characterized in that the length of the shank is less than the width of the retainer. The assembly according to claim 13, characterized in that the nut body and the retainer are composed of different materials, the retainer is of greater hardness than the nut body. 15. The assembly according to claim 10, characterized in that the collar is unitary with the nut body. 16. The assembly according to claim 15, characterized in that the opening is substantially larger than the outer diameter of the collar. 17. The assembly in accordance with the claim 16, characterized in that the diameter of the inner wall of the retainer is smaller than the diameter of the opening. 18. The assembly in accordance with the claim 17, characterized in that the nut body further includes tool coupling means for rotating the nut body. SUMMARY OF THE INVENTION A two-part fastening system uses separate parts, a nut and a retainer, which securely join from opposite sides of the capture element such as a sheet or panel. The nut body having an axial threaded bore, includes an integral collar located on one side of the nut having an outer diameter smaller than the outer diameter of the nut body. A unitary tubular rod with the nut body extends coaxially from the collar, the outer diameter of the rod is less than the outer diameter of the collar. The stem includes an expansion portion near its end that is deformable to provide connection to the second part, a retainer having a bore that receives the expansion portion of the stem. The perforation of the retainer includes an inner wall against which the expansion portion of the stem is forced to achieve connection of the parts. The width of the retainer preferably is greater than the length of the rod, such that once connected, the end of the rod is below the end face of the retainer. The inner face of the retainer abuts butt an annular end of the collar, such that the forces between the retainer and a threadedly connected part can not be transferred through a deformable portion of the stem. The retainer may be composed of harder material or one that provides reduced friction to improve its capacity as a load bearing, rotational surface. The two parts are assembled with the panel by inserting the tubular stem of the nut through the panel opening, installing the retainer on the stem from the opposite side of the panel and then deforming the stem against the inner wall of the retainer.