Metal working – Means to assemble or disassemble – With magazine supply
Reexamination Certificate
1999-07-27
2001-07-31
Hughes, S. Thomas (Department: 3726)
Metal working
Means to assemble or disassemble
With magazine supply
C029S525010, C029S03400A, C029S798000, C029S243530
Reexamination Certificate
active
06266871
ABSTRACT:
This invention relates to a method of and an apparatus for simultaneously feeding multiple fasteners to a workpiece. The invention can be used, for example, to apply fasteners which have a shank and an enlarged head, and is particularly useful where the space between fastening points is inadequate to allow simultaneous access for individual fastener feed mechanisms and/or where the fastening points lie in a number of different planes.
DESCRIPTION OF PRIOR ART
Fastener application machines for applying single fasteners in sequence are well known. Such fastener application machines can be mounted in groups to apply a plurality of fasteners simultaneously, but each machine requires space around an axis along which the fasteners are to be applied to a workpiece, the space being required to mount a fastener feed mechanism, a plunger actuating mechanism and, where required, a setting die support means. Even if the frames of the machines are merged such that one frame can support a plurality of plungers and dies, an individual fastener feed mechanism is required for each fastening point.
There are numerous industrial applications, such as the assembly of side walls for heavy vehicle trailers, in which the required fastener spacing is less than the minimum spacing obtainable with fastening machines according to current practice. Trailer side walls are typically 15 meters long and 3 meters high, and are built in sections which are fastened together with twin-rows of rivets with the rows being 50 mm apart and the pitch of the rivets within the rows may be less than 40 mm. For minimum cost production all the rivets in both rows should be fed and set simultaneously, but due to the limited space available between the rivets this is not possible with currently available fastener application machines.
OBJECT OF THE INVENTION
It is therefore an object of the present invention to provide a method of and an apparatus for feeding fasteners to a workpiece which overcome the above disadvantages.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided a method of feeding multiple fasteners to a workpiece in which the fasteners are mounted in a flexible carrier tape which passes through a guide and indexing means to bring a fastener into axial alignment with a plunger, wherein the fasteners are pre-loaded in the carrier tape in a pattern which simultaneously brings a fastener into axial alignment with a plunger at each of a plurality of fastening positions relative to the workpiece.
Such a method allows simultaneous application of multiple fasteners in situations where the distance between fastening points is significantly less than can be achieved by current fastener application practice.
Preferably, the carrier tape simultaneously brings a fastener into axial alignment with a plunger and a die at each of the plurality of fastening positions.
The distance between each fastener is ideally a multiple of a predetermined unit spacing. The tape indexing means is preferably adapted to index the carrier tape at successive indexes by a variable distance which is a multiple of the predetermined unit spacing. The guide may create a path length between each of the plurality of fastening positions which is an integral multiple of the predetermined unit spacing.
The carrier tape may be pre-loaded with fasteners in a pattern of spacing identical to the pattern of spacing of the fastening positions. Moreover, the carrier tape may be pre-loaded with a plurality of patterns of fasteners, the fasteners of one pattern being interspersed between the fasteners of another pattern.
The carrier tape is ideally flexible about an axis transverse to the longitudinal direction of the tape and/or about an axis parallel to the longitudinal direction of the tape. In this way it is possible to bring the fasteners to any desired fastening points in any plane.
According to another aspect of the present invention there is provided an apparatus for applying multiple fasteners to a workpiece, wherein the apparatus comprises a guide manifold which includes:
a top plate having mounted therein a plurality of plungers which are axially aligned with a plurality of fastening positions;
at least one tape guide adapted to guide at least one tape carrying fasteners such that the fasteners are axially aligned with the fastening positions; and
at least one tape indexing means adapted to bring a fastener into axial alignment with the plunger at each of the fastening positions.
The apparatus may include a bottom plate provided with a plurality of dies which are axially aligned with the plurality of fastening positions. The bottom plate may be mounted on a bottom platen of a power press.
The top plate may be adapted for movement with a top platen of a power press.
Alternatively, the top plate and the bottom plate may comprise the top and bottom platens of a power press.
The tape indexing means may be adapted to index the carrier tape at successive indexes by a variable distance which is a multiple of a predetermined unit spacing. The tape guide may create a path length between each of the plurality of fastening positions which is an integral multiple of the predetermined unit spacing.
The fastening positions may lie substantially in a straight line.
Clamping means may be provided for pre-clamping the workpiece prior to fastener application.
The guide manifold may be mounted on a prime mover in a manner which permits limited positional freedom relative to the prime mover, whereby the guide manifold can engage positioning means to bring the plungers into precise axial alignment relative to the fastening positions.
The plungers may be adapted to urge the fasteners from the carrier tape into delivery tubes for guiding the fasteners to the required fastening positions. The delivery tubes may incorporate an axially continuous longitudinal constriction to restrain the fasteners from free-fall and for preserving a desired fastener orientation. Such delivery tubes are described in EP-A-0 567 240. The delivery tubes may be adapted to receive the fasteners head-first from the carrier tape. The guide manifold may incorporate an aperture between the delivery tubes and the dies to permit the passage of a workpiece with sufficient clearance to allow the workpiece to be lifted clear of the dies after the fasteners have been applied.
For a better understanding of the present invention and to show more clearly how it may be carried into effect reference will now be made, by way of example, to the accompanying drawings in which:
REFERENCES:
patent: 0567240 (1993-10-01), None
patent: 0018269 (1977-02-01), None
patent: 9628266 (1996-09-01), None
Ariel Industries PLC
Cozart Jermie E.
Dorman Ira S.
Hughes S. Thomas
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