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US 4,044,667 AGranted
Mandrels for supporting containers with negative and positive air pressure
AssigneeChromax Limited
InventorJohn Maxwell Jackson
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AssigneeChromax Limited
InventorJohn Maxwell Jackson
Estimating the term…
A machine for printing on thin-walled frusto-conical containers having little resistance to transverse deformation is provided with rotatable mandrels for holding and centering the containers during printing. Each mandrel has a rotatable body provided with two axially spaced centering rings adapted to engage the walls of the container and centralize the container relative to the axis of the mandrel upon axial movement of the container on to the mandrel. The centering rings make sealing engagement with the walls of the container and subdivide the space enclosed between the container and the mandrel body into an end chamber between the base of the container and the outer end of the mandrel, and an annular chamber between the side wall of the container and the mandrel body. The mandrel body is provided with suction conduit means for extracting air from the end chamber so as to hold the container on the mandrel with the centering rings in sealing engagement with the container walls, and the mandrel body is also provided with pressure conduit means for supplying compressed air to the annular chamber to support the side wall of the container against transverse deformation during a printing operation.
A rotary mandrel for holding and centering a container having a base, a side wall which is circular in cross-section and an open top at the end of the side wall remote from the base, said mandrel comprising a body having an inner end thereof mounted on a support and an outer end insertable into the interior of the container through the open top thereof, the mandrel body being rotatable about the longitudinal axis of the mandrel body and having two axially spaced centering rings on the periphery thereof co-axial with said rotational axis, said centering rings being engageable with the side wall of the container to centralize the container with respect to said rotational axis upon axial movement of the container on the mandrel body towards the inner end thereof, and said rings subdividing the space enclosed between the container and the mandrel body therein into an end chamber between the mandrel body and the base of the container and an annular chamber between the mandrel body and the side wall of the container, said end chamber being pneumatically sealed from said annular chamber when said centering rings engage a side wall of a container fitted on the mandrel, first conduit means in the mandrel body for extracting air from said end chamber, and second conduit means in the mandrel body for supplying fluid under pressure to said annular chamber whereby, in operation, the difference between the pressure in the end chamber and atmospheric pressure exerts a force on the base of the container holding the container on the mandrel, and the pressure of the fluid in the annular chamber supports the part of the container side wall between the centering rings.
A multi-cylinder printing machine for printing on containers of a standard size each having a base, a side wall which is circular in cross-section and an open top at the end of the side wall remote from the base, said printing machine comprising a frame, a turret rotatably mounted on the frame, and a plurality of rotary mandrels mounted on the turret and adapted to hold said containers, said frame having a plurality of stations disposed around the turret, said stations including a container loading station, a container unloading station, and printing stations between the container loading and unloading stations in the circumferential direction of the turret, and said turret being angularly movable to index each mandrel in succession to each of said stations, wherein each of said mandrels comprises a support member on said turret, a mandrel body mounted on said support member for rotation about the longitudinal axis of the mandrel body, said mandrel body having an outer end insertable into the interior of one of said containers through the open top thereof and having two axially spaced centering rings on the periphery of the mandrel body co-axial with said longitudinal axis, said centering rings being engageable with the side wall of the container to centralize the container with respect to said longitudinal axis upon axial movement of the container on the mandrel body towards its support member, and said rings sub-dividing the space enclosed between the container and the mandrel body therein into an end chamber between the mandrel body and the base of the container and an annular chamber between the mandrel body and the side wall of the container, said end chamber being pneumatically sealed from said annular chamber when said centering rings engage a side wall of a container fitted on the mandrel, first conduit means in the mandrel body for extracting air from said end chamber, and second conduit means in the mandrel body for supplying fluid under pressure to said annular chamber, and wherein said frame includes a vacuum conduit connectable to a source of vacuum, a pressure conduit connectable to a source of fluid under pressure, and distribution means operable upon rotation of the turret to connect said first conduit means of each mandrel to said vacuum conduit during passage of said each mandrel through the loading station and printing stations and to connect said second conduit means of each mandrel to said pressure conduit during passage of said each mandrel through the printing stations, whereby, during passage of said each mandrel through the printing stations, the difference between the pressure in the end chamber and atmospheric pressure exerts a force on the base of the container holding the container on the mandrel, and the pressure of fluid in the annular chamber supports the part of the container side wall between the centering rings.
Dependencies are inferred from the claim text.
Drawings are temporarily unavailable. Open the PDF at USPTO
Printing apparatus or machines of special types or for particular purposes, not otherwise provided for: for printing on curved surfaces of conical…
On articles of uniform cross-section, e.g. pencils, rulers, resistors: by rolling contact
Printing machines or presses
Term ended 30 Aug 1994 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
This invention relates to mandrels for supporting open-topped containers of circular cross-section, for example cylindrical or frusto-conical containers, and is concerned more particularly, but not exclusively, to mandrels suitable for use in a multi-cylinder printing machine as described and illustrated in British patent specification No. 1,316,272.
In the printing of containers mounted on rotary mandrels, it is essential for satisfactory results that the containers be accurately centered relative to the rotational axis of the mandrel, since otherwise the pressure between the printing plate and the container would vary during rotation of the mandrel. Various constructions of expandable mandrels comprising collars slidable along tapered cores have been proposed for holding and centering containers in printing machines, but such mandrels are not suitable for use with thin walled containers having little resistance to transverse deformation, since the pressure between the printing plate and a part of the container supported by a collar of the mandrel tends to be greater than the pressure between the printing plate and a part of the container not so supported.
According to the present invention there is provided a mandrel for holding and centering an open-topped container of circular cross section, comprising a rotatable body having an outer end which is adapted to extend into the interior of the container through the open top thereof, two axially spaced centering rings secured to or integral with said body, the two rings being adapted to engage the walls of the container and centralize the container relative to the axis of the mandrel upon axial movement of the container on the mandrel towards the inner end thereof, and said rings subdividing the space enclosed between the container and the mandrel body therein into an end chamber between the outer end of the mandrel and the base of the container and an annular chamber between the mandrel body and the side wall of the container, suction conduit means for extracting air from said end chamber, and pressure conduit means for supplying air or other fluid under pressure to said annular chamber whereby, in operation, the difference between the pressure in the end chamber and atmospheric pressure exerts a force on the base of the container holding the container against the centering rings, and the pressure of the fluid in the annular chamber supports the part of the container wall between the centering rings.
Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a sectional elevation view of a multi-cylinder flexographic printing machine fitted with mandrels for supporting cylindrical containers in accordance with the invention,
FIG. 2 is a sectional elevation view, on a larger scale, of part of the machine of FIG. 1, showing one of the mandrels and its supporting and drive mechanism,
The multi-cylinder flexographic printing machine shown in FIG. 1 is substantially the same as the printing machine shown and described in British patent specification No. 1,316,272 except that the turret is fitted with mandrels in accordance with the present invention. A brief description of the construction and operation of the printing machine is given hereinafter to facilitate understanding of the operation of the mandrels illustrated in the drawings, but the same reference numerals have been used to identify similar parts of the two printing machines and reference may be made to British patent specification No. 1,316,272 for a fuller description of the parts of the machine not connected with the mandrels.
Referring now to the drawings of the present application, the machine shown in FIG. 1 comprises a base 10 having a peripheral wall 11, several printing cylinders 12 mounted one at each of separate printing stations B spaced apart around the outside of the wall 11, a turret 13 rotatably mounted on a vertical spindle 14 on the base 10, the turret having a plurality of mandrels 15 spaced at equal angular intervals around the periphery of the turrret, a master gear unit 16 rotatably mounted on the turret and adapted to rotate the printing cylinders 12 and mandrels 15 in synchronism, and a Geneva indexing mechanism 17 operable to index the turret in one direction of rotation to register each mandrel in turn at a loading station A (FIG. 3), each of the above mentioned printing stations B, each of several drying stations C disposed one between each adjcent pair of printing stations, a final drying station X, and then at an unloading station Y. The containers to be printed are mounted on the mandrels. An air distribution ring 100 fixed to the frame of the machine controls supply of air under pressure and the application of vacuum to conduits leading to the mandrels to hold and support containers mounted on the mandrels in accordance with rotation of the turret as hereinafter described.
As shown in FIG. 2, each mandrel 15 is fitted on the outer end of a spindle 101 rotatably mounted in the turret 13 by bearings 102, 103 spaced apart by two annular spacers 104, the axis of the spindle being radial relative to the rotational axis of the turret. The inner end portion of the spindle is fitted with a bevel gear 29 which meshes with a bevel gear 41 forming part of the master gear unit 16 rotatably mounted on the turret, whereby rotation of gear 41 rotates all the spindles 101 and mandrels 15 in synchronism.