Conveyors: power-driven – Conveyor section – Endless conveyor
Reexamination Certificate
1998-10-23
2001-01-16
Kramer, Dean J. (Department: 3652)
Conveyors: power-driven
Conveyor section
Endless conveyor
Reexamination Certificate
active
06173832
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to improvements in or relating to assembly line systems and is particularly concerned with conveyor chains used in such systems.
Cardanic conveyor chains are well known and may be utilised to carry pallets to various work stations along the assembly line, said pallets carrying workpieces to be operated on at the work stations.
In many known arrangements, the conveyor chains comprise chain links connected together in such manner that gaps occur in between the links on either side of the central axis of the conveyor chain, in order to allow the chain to follow a curved path in a generally horizontal plane. As the chain negotiates such a curved path the gaps on the inside of the curve tend to close whilst the gaps on the outside of the curve tend to open wider. Such gaps have been recognised as undesirable since it is possible that a finger, for example, could be trapped in such a gap and injured. Disadvantages of connecting together the links of the conveyor chain in such a manner that these gaps exist are discussed in Patent Specification No. WO 94/26636 and that Patent Specification outlines an arrangement including a disc-shaped element that covers the gaps during such relative rotation of the links in a horizontal plane. Other arrangements have been proposed for covering the gaps which include crescent fin-like projections that cover the gaps, although such proposals have been found to impose a restricted movement of the links relative to one another about a generally horizontal axis.
Whilst the arrangement shown in Patent Specification No. WO 94/26636 apparently shows an arrangement in which the movement about two mutually orthogonal axes is less restricted than some other arrangements including disc-shaped elements covering said gaps, it is believed that there still tend to be disadvantages with that arrangement.
For example, although the disc elements cover the gaps in the chain shown in WO 94/26636, the disc elements themselves are below the upper level of the chain thus creating shallow recesses an either side of the central axis of the chain which could lead to an ingress of dirt or other particulate matter. Furthermore, it is believed that the conveyor chain could be manufactured in a more efficient, simpler or cost-effective manner.
SUMMARY OF THE INVENTION
It is an object of the present invention to at least alleviate one or more of the aforementioned, or other, disadvantages associated with a conveyor chain incorporating some means to cover the gaps between the links of the chain.
According to the present invention there is provided a conveyor chain including links connected together to be rotatable relative to one another about mutually orthogonal axes, the chain having gaps in between the links to allow the chain to follow a generally curved path, in use, in a generally horizontal plane, said gaps on the inside curvature of the chain closing with the gaps on the outside of the curvature opening, said gaps being covered by plate means during rotation of the links in said generally horizontal plane, the conveyor chain being characterised in that the upper surface of the plate means is generally co-planar with the upper surface of the links and/or in that the chain is made up of units each comprising a link and plate means integrally formed with a core that is positioned within, and formed separately from, the link, said units being connected to one another by means of pivot pins that pass through said cores.
In an alternative embodiment, it is possible that said plate means is fastened to the core in overlying relationship rather than being integrally formed therewith.
Further according to the present invention there is provided an assembly line system including at least one conveyor chain in accordance with either of the immediately preceding paragraphs.
Preferably, the plate means is in the form of a disc element having a curved or part-circular head portion received in a stepped guide recess in the adjacent link thereby allowing relative rotation of two adjoining links, in use, generally in a horizontal plane. The disc element may be provided with a base portion overlying a generally C-shaped annular portion of the link receiving the core that is connected with the disc element. The head portion of the disc element may be provided with rearward chamfered straight edge boundaries adjacent front (preferably curved) upper surfaces of the associated link and said rearward edge boundaries may act to limit or restrict the degree of rotation of adjoining links relative to one another in an upward and/or downward sense of rotation.
Further according to the present invention there is provided a conveyor chain having one or more of the following features:
(a) gaps in between links of the chain on each side of the axis of the chain said links being rotatable relative to one another in a generally horizontal plane, in use, (or in the plane of the links when aligned) in order for the chain to follow a curved path in said generally horizontal plane, each link having a flat upper surface which is stepped down to provide a guide recess for a disc element that covers the gaps during relative rotation of the links in said generally horizontal plane, each said link preferably having a generally C-shaped annular portion which receives a core connected to the disc element with the disc element overlying said C-shaped annular portion,
(b) links including a generally C-shaped portion receiving a core with an overlying disc element arranged to cover gaps occurring in between the links, during relative rotation of said links in a generally horizontal plane, in use,
(c) links connected together with gaps occurring on each side of a central axis of the chain, said gaps being covered by disc elements during relative rotation of the links in a generally horizontal plane in use, the complete upper surface of the disc elements being visible from above the chain and presenting a substantially flat upper surface substantially co-planar with the upper surface of the links, said disc elements being received in guide recesses in the links, and
(d) a series of interconnected links receiving disc elements that cover gaps in between the links during relative rotation of the links in a generally horizontal plane in use, the upper surfaces of the disc elements being substantially exposed and presenting a flat surface to the conveyor belt in conjunction with upper surfaces of the links.
Further advantageous features of the present invention will be apparent from the following description and drawings.
REFERENCES:
patent: 2319617 (1943-05-01), Manierre
patent: 2619843 (1952-12-01), Kampfer
patent: 3317030 (1967-05-01), Davis
patent: 3493097 (1970-02-01), Karr
patent: 3895691 (1975-07-01), Shiraishi
patent: 4524865 (1985-06-01), Von Hofen
patent: 4895248 (1990-01-01), Wahren
patent: 5402880 (1995-04-01), Murphy
patent: 5407061 (1995-04-01), Okada et al.
patent: 5429227 (1995-07-01), Krossmann et al.
patent: 5586644 (1996-12-01), Coen et al.
patent: 5803236 (1998-09-01), Wahren
patent: 1.095.233 (1955-05-01), None
patent: 94/26636 (1994-11-01), None
Jaketic Bryan
Kramer Dean J.
Pillsbury Madison & Sutro LLP
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