Fastener delivery tube

Abstract

A fastener delivery tube (21) incorporates an internal guide (22)—such as a continuous sleeve lining, flexible, or resiliently deformable spring strips (34, 37, 38) or re-circulating balls (54)—forming a longitudinally movable constriction, inhibiting fastener free-fall through the tube and preserving fastener orientation, by maintaining fastener (25) contact with a driving plunger (28) in its passage there-through and upon exit there-from into contact with a workpiece.

Description

[0001]This application is a reissue of U.S. application Ser. No. 08 / 049,083, filed on Apr. 20, 1993, now U.S. Pat. No. 5,398,860.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This invention relates to the presentation of fasteners to workpieces. More specifically, it relates to fasteners which are to be machine applied and need to be fed, through a delivery tube, from a supply, such as a carrier tape, to a remote workpiece—often with restricted access.[0004]2. Description of the Prior Art[0005]It has been found desirable to provide such a delivery tube with the capability of exerting a controlled restraining force, sufficient to hold the fasteners in a desired orientation throughout their passage through the tube—but preferably without marking the fastener body.[0006]The term tube is used herein to embrace any configuration or disposition of chamber, enclosure or passageway.[0007]The term fastener is used herein to embrace a disparate variety of elements for joinin...

AI Technical Summary

Benefits of technology

[0018]More particularly, by contriving that such a constriction moves longitudinally of the delivery tube, co-operatively in conjunction with fastener movement through the tube, both fastener free-fall can be restrained and a desired fastener orientation preserved.

[0023]It has also been found that the restraining force can be successfully applied by deploying internally and longitudinally of the delivery tube strips of spring material or mounted strips of spring-loaded rigid, or semi-rigid material.

[0030]The restraining force which the balls can apply to a fastener can be controlled, by ensuring that they are brought into contact with a friction pad, disposed so that all the balls in the loop have to pass by it in the course of a complete revolution or passage around a loop.

[0034]According to one aspect of the invention there is provided a delivery tube for a fastener application machine, for transferring fasteners with a shank and relatively enlarged head, discretely in succession, from a supply, such as a carder tape, to a fastening station, at which fasteners are applied to a workpiece, by a driving head of a fastener application plunger, movable internally of the delivery tube, the delivery tube incorporating a guide, to bear upon a fastener in its transit through the delivery tube, by forming a local passage constriction, movable longitudinally of the tube, co-operatively in conjunction with fastener movement, to restrain the fastener head from free-fall there-through, and preserve a desired fastener orientation within the guide.

Problems solved by technology

It has been found that, in circumstances where it is not possible to use a guidance tool, and where the fastener has an inadequate bearing surface on its major diameter, or where the length of the fastener is small relative to its diameter, it is often advisable to restrain the fastener during its passage through the delivery tube by exerting a restraining or gripping action or force sufficient to prevent any movement of the fastener under its own weight.

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