The present invention pertains to the construction art and, more particularly, to apparatus for, and a method of providing a threaded insert in a work piece.
Applications commonly exist in mechanical construction for providing threaded inserts within a base structure. Where the base structure is relatively soft, such as mild steel, aluminum, phenolic laminates or fiber-reinforced plastics, merely drilling a hole and then tapping does not produce satisfactory results. In addition, where threaded inserts are to be provided in a soft base material it is important that the insert be installed without any driving forces, as by hammering, which may tend to shock or deform the structure during installation.
In addition, particularly where the insert is to be placed in a soft base material, it is important that the means for retaining the insert in the base material not allow the insert to work its way loose from the material in use.
Additional desirable features of such an insert are that:
(1) it be installable from the face side of the base material; PA1 (2) no special tools or bolts be required; PA1 (3) its holding power in the base material increase linearly with applied force; PA1 (4) it be simple and low cost to manufacture; and PA1 (5) it be simple and easy to install.
The prior art has developed numerous devices which are intended for use as threaded inserts. These commonly take the form of expansion bolts wherein an assembly, including a bolt, is driven into a hole provided in the working material. Rotation of the bolt causes the assembly to expand into and grip the working material, thereby forming the threaded insert. None of such assemblies known to the prior art provide the various features detailed above. In particular, none of the prior art insert assemblies has proved itself to be well suited for insertion into soft base or working materials.