Prior to the present invention, various spring nut units have been devised to be preassembled onto support structures to subsequently receive threaded fasteners so that another structure can be attached thereto. These units include a wide arrangement of J and U type spring nuts to function with a variety of threaded fasteners. U.S. Pat. No. 3,426,818 issued Feb. 11, 1969 to MT Derby for Yielding Nut Retainer and U.S. Pat. No. 4,798,507 issued Jan 17, 1989 to B. Otah for Sheet Metal U-Nut disclose some examples of prior art spring nuts.
While such spring nuts generally meet requirements for basic attachment purposes, they do not meet new and higher standards for improved assembly of different components to one another particularly where the different components are produced in quality with large limit stack or tolerances. The resilient retainer ring "R" of the prior art spring nut "N" of FIG. 3B securely holds the spring nut in an installed and nonfloating position in the locating hole or opening "O" in support "S" and further reduces the ramping of the nut on the support and thereby the misalignment of the opening in a panel being attached with the threaded retainer "T" of the nut.
In contrast to prior art fixed nut constructions, the present invention is drawn to a new and improved floating spring nut having an extruded adjustment limiter collar extending downwardly from the upper spring leaf that fits into an enlarged fastener receiving opening in the support that allows limited adjustment of the nut on the support or a first component so that a second component can be aligned therewith and securely fastened thereto with a threaded fastener. The spring nut of this invention is generally retained in any position by the collar and spring action of the upper and lower leaves or arms on a supporting component. The nut after appropriate adjustment efficiently receives and guides a threaded fastener into threaded connection with the nut so that the components can be readily connected to one another by the fastener extending through aligned holes in the components.
More particularly, the floating spring nut of this invention is, in one preferred embodiment, generally U shaped in cross section, provides improved retention and adjustment in its fastening plane and features a cylindrical locating and retaining adjustment collar instead of an inclined resilient locating and retaining ring found on a typical prior art U nut. However, the collar of this floating U nut fits with some clearance in the locating hole of the prior construction of FIG. 3B so that there is some float for adjustment purposes. However, the locating hole in the support for the floating nut preferably has a sufficiently larger tolerance diameter wise to provide additional clearance in any direction in its plane for optimized float of the spring nut. With such larger diameter holes, a relatively large tolerance zone is established in which the nut can be adjusted in the plane of the support component.
The ability of the spring nut to float provides greater flexibility in assembly and connection of a wide range of different and mass-produced components to one another. This invention accordingly enhances the assembly of structures from various sub-components manufactured with large tolerance and eases the effect of manufacturing tolerance stack-ups This adjustability is important to the proper installation and location of many components, particularly finishing components where positioning and adjusting trim panels and other structures is often needed for close fits.
A feature of this invention is in the new and improved locating and retaining collar extruded or otherwise formed in one of the leaves of the spring nut. This collar in cooperation with the edge of the hole in the support establishes the distance that the spring nut is allowed to float.
Moreover the present invention is easily used with a wider range of thickness in support structures and provides assured alignment of the fastener opening provided by the collar in the upper arm with the screw receiving sleeve in the lower arm. This invention accordingly provides a new and improved method of fastening components to one another having a wide tolerance range