Printing – Stenciling
Patent
1989-04-10
1990-10-16
Burr, Edgar S.
Printing
Stenciling
101115, 101123, B41F 1536
Patent
active
049627023
DESCRIPTION:
BRIEF SUMMARY
This invention relates to an improved print head assembly for use in screen printing machines and more particularly to printing machines of the carouse type.
Screen printing machines of this type may comprise a multiple armed fixed frame and a complementary multiple armed frame which is mounted for rotation relative to the fixed frame. The machine further includes a plurality of print heads and screen platens one group being operatively connected to respective movable arms and the other group being operatively connected to respective fixed arms. Each print head comprises a movable carriage which is mounted for reciprocating movement relative to the arm upon which it is mounted the carriage having suitable spray heads and/or other application devices thereon.
One currently known means for driving each carriage comprises a piston/cylinder assembly which is mounted to a respective arm of the frame and is arranged with the piston rod being connected more or less directly to the carriage with the carriage being located beyond the piston rod at the outer end of the arm.
A major disadvantage of this arrangement is that in many instances extremely long frame arms are required to mount the piston/cylinder assembly in line with the carriage. This particular in-line arrangement can also lead to a general lack of stability in the mounting of the cylinder to the arm. Furthermore, access to the cylinder for the purpose of adjustment can be difficult because it is spaced so far from the free end of the frame arm.
It is an object of the present invention in one aspect to provide an improved print head assembly which alleviates one or more of the aforementioned problems.
According to one aspect of the present invention there is provided a print head assembly for use with a screen printing machine of the type including a multiple armed fixed frame and a complementary multiple armed movable frame which is mounted for rotation relative to the fixed frame, the print head assembly comprising: a mounting frame operatively connected to an arm of the carousel; a carriage operatively connected to the mounting frame and arranged for reciprocating movement relative thereto along a path of travel; drive means for causing the reciprocating movement, the drive means comprising a piston/cylinder assembly having a longitudinal axis, a cylinder having opposed ends with a piston rod extending from one of those ends there being a region defined between the lateral axes at respective ends of the cylinder these lateral axes extending at right angles to the longitudinal axis of the assembly; the carriage being operatively connected to the piston rod by coupling means and arranged so that at least along part of its reciprocating path of travel it is disposed within the region.
The mounting frame may include at least one elongated guide member along which the carriage can travel. Preferably the longitudinal axis of the guide member and the cylinder are substantially parallel and laterally off-set from one another. It is desirable that the cylinder of the piston/cylinder assembly is mounted in fixed relation on the mounting frame.
The mounting frame may further include a pair of spaced apart end plates with the cylinder of the piston/cylinder assembly being mounted between those end plates. The elongated guide member is preferably also mounted between the end plates parallel to and spaced from the cylinder. Preferably the guide member is disposed below the cylinder. It will be appreciated that the piston/cylinder assembly can be either pneumatic or hydraulically actuated and suitable valves and other controls are provided to control its stroke.
The coupling means for operatively connecting the piston rod to the carriage, may include an elongated transfer tube which extends generally parallel to the piston rod and a coupling plate operatively interconnecting the piston rod and the transfer tube. Conveniently the transfer tube can be used for housing delivery lines for the spray heads on the carriage.
A support rod may be provided for slidably mount
REFERENCES:
patent: 2484671 (1949-10-01), Bauman
patent: 2695592 (1950-02-01), Szczepanski
patent: 2885957 (1959-05-01), Hansen
patent: 3096709 (1963-07-01), Eldred et al.
patent: 4084504 (1978-04-01), Fuchs
patent: 4649815 (1987-03-01), Richardson
patent: 4750419 (1988-06-01), Meredith
patent: 4753162 (1988-06-01), Bubley
Burr Edgar S.
Keating Joseph R.
Reefdale Pty. Ltd.
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