Metal working – Method of mechanical manufacture – Spring making
Reexamination Certificate
1999-04-08
2001-09-25
Hughes, S. Thomas (Department: 3726)
Metal working
Method of mechanical manufacture
Spring making
C029S433000
Reexamination Certificate
active
06293015
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention pertains to an apparatus for rotating and simultaneously opening a split ring to facilitate attachment of an object to the ring or to use the ring to interconnect two or more objects.
A split ring comprising a piece of wire formed into two circular coils lying in tight back-to-back relation is well known as convenient means for attaching a variety of objects in a secure, but if necessary demountable, manner. Key rings are one example of the multitude of uses to which split rings are adapted. Split rings are also widely used in the assembly of many products, one of which is the currently popular remote control for keyless vehicle entry systems. The use of split rings for keyless entry remote controls may be to some extent a vestige of the key ring technology being replaced, but split rings still provide a convenient means by which the vehicle owner may retain conventional keys, identification tags, and the like with the remote control.
A split ring is typically characterized by two coils of a single length of wire formed back-to-back in a tight coil with the opposing surfaces flattened somewhat and the opposite free ends spaced by a small gap on opposite sides of the wire at the point of wire crossover from one coil to the other at approximately the midpoint along the wire. In any assembly technique, a narrow-edged tool is typically inserted into the split between the coils and adjacent one free end of the wire to allow the closed-loop objects intended to be attached to the ring to be slipped over the free end. Thereafter, the ring is simply rotated or turned with respect to the object approximately one complete turn to allow the object to travel along the split between the two coils until it reaches the opposite free end, whereupon the object completely encircles the ring coil and is secured thereto.
Equipment of various types has been developed to facilitate the assembly of objects to split rings. Such equipment has varied in complexity from a simple hand-held pliers device including a pointed tooth on one jaw to facilitate opening the split in the ring, to more complex semiautomatic assembly equipment which actually holds, positions, and opens a ring in a manner to allow an operator to handle only the object or objects to be attached to the ring. Examples of prior art devices are shown in U.S. Pat. Nos. 3,340,595 and 3,596,341. An improvement in semiautomatic assembly equipment is disclosed in U.S. Pat. No. 5,077,877, which apparatus can accurately and reliably handle a range of sizes of split rings to present the rings in sequence and in proper orientation for rapid operator-assisted assembly of an object or objects to the ring.
SUMMARY OF THE INVENTION
The present invention provides an improved split ring assembly apparatus which is particularly well adapted for high volume automated assembly of split rings to objects or to the interconnection of two or more objects with a split ring. The method of operation of the apparatus of the present invention also provides a unique approach to split ring assembly.
The apparatus operates to simultaneously turn and open a split ring in a manner which facilitates automated attachment of any closed perimeter object or objects to the ring. The apparatus includes a rotatable ring drive spindle which engages the circular rear face of a split ring. The spindle has a drive pin which defines a path of rotation on the arc of the circular face of the ring and the pin has an edge which engages the gap in the rear face of the ring in response to rotation of the drive spindle to turn the ring. A wedge is positioned to engage the front circular face of the ring and has a leading edge which is biased against the front face and positioned to enter the other ring gap in response to ring rotation to open the ring.
The apparatus preferably includes an outer housing having a cylindrical through bore. The drive spindle is cylindrical in shape and is mounted for independent rotational and axial movements in the through bore of the housing. The diameter of the drive spindle corresponds to the outside diameter of the split ring and the spindle includes an annular ring-engaging axial end. The drive pin is mounted on the axial end of the drive spindle and at the outer cylindrical surface thereof. The axial end of the drive spindle is provided with a flat circular face generally perpendicular to the spindle axis and a peripheral ring-receiving groove which surrounds the circular face. The peripheral groove in the end face of the spindle is shaped to conform to the rear face of the split ring. The drive pin extends into the peripheral groove.
The ring splitting wedge is pivotally attached to the housing on a pivot pin which is disposed with its axis generally radially extending with respect to the housing bore and the cylindrical drive spindle. The leading edge of the wedge is positioned generally parallel to the pivot pin axis and an axial outer wedge surface extends from the leading edge at an acute angle with respect to the plane of the split ring. The wedge is preferably provided with an inner wedge surface which extends from the leading edge generally parallel to the plane of the split ring, but has a recessed portion near the leading edge to provide clearance for the crossover portion of the split ring adjacent to the gap in the front face of the ring.
The housing includes a ring loading slot which extends laterally into the through bore and defines a delivery path to bring a split ring into alignment with the ring-engaging end of the spindle. An indexing device axially positions the drive spindle in the housing bore in the loading position with the ring-engaging end and the drive pin withdrawn from the delivery path, and an operative position in engagement with the rear face of the split ring.
In accordance with the method of the present invention, a conventional split ring is opened for assembly by the steps of (1) rotating the ring on the axis of its coils by engaging the wire end in the gap in one coil with a rotary pin, (2) positioning a wedge having a lead edge in biased contact with the coil on the opposite face of the ring and causing the edge to enter the gap in the coil on said opposite face, and (3) continuing to rotate the ring to cause the wedge to progressively separate one coil from the other.
REFERENCES:
patent: 3340595 (1967-09-01), Hoadley
patent: 3596341 (1971-08-01), Herkner
patent: 5077877 (1992-01-01), Piotrowski
Andrus Sceales, Starke & Sawall
Hong John C.
Hughes S. Thomas
Worth Manufacturing Company
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