Shim supported upon a pivot pin between upper and lower receivers of an ar-15/m16/m4 style firearm and for reducing misalignment and play

Abstract

An improved shim construction incorporating a thin body exhibiting a profile generally matching a selected mounting ear of a lower assembleable receiver, the shim including an arcuate perimeter with an flat interconnected base surface. The body exhibits an aperture defined therein such that, upon placement between an inner facing surface of the ear and an intermediate positioned cylindrical shaped portion, a subsequent widthwise traversing installation of a pivot pin causes the shim body to be sandwiched between the receivers to occupys an excess tolerance, thereby reducing or eliminating instances of misaligning slop or play exhibited between the receivers. The shim may exhibit a thickness in a range of 0.001″ to 0.010″. A plurality of shims can be provided as a kit and which are applied in scalable fashion to compensate for varying excess tolerance established between the receivers.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]The present invention claims the priority of U.S. Ser. No. 61 / 530,429 filed Sep. 2, 2011.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention teaches an improved shim stock design, improving upon prior art disc shaped shims. The improved shim exhibits a thin arcuate body with a flat bottom which matches the profile of either of the spaced apart ears associated with the lower receiver and between which seats a tubular shaped and downwardly extending protrusion associated with the upper receiver. The shim can be employed either singularly or in a plural / stackable fashion and in order to eliminate the existence of excess tolerance (spacing) exhibiting between the upper and lower receives, such as which is further characterized as “slop” or “play” and which can otherwise result in misalignment between the receivers.[0004]2. Background of the Relevant Art[0005]Firearms such as the M16 / M4 / AR15 rifle include uppe...

AI Technical Summary

Benefits of technology

The improved shim construction has a thin body that matches the shape of a selected ear and is connected to a flat base surface. It has a hole in the middle through which a pivot pin can be installed to secure it between two parts. This design helps to align and reduce any misalignment or play between the parts, making it easier to assemble and use them together.

Problems solved by technology

A problem commonly associated with such assembled receivers is the incidence of “slop” or “play” and which is defined as any degree of looseness in the tolerance established between the aligning lugs and ears.

Such looseness in the inter-fitting of the parts can be the cause of undesirable rattling or noise.

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