US3202089A - Single sheet presses - Google Patents

Description

1965 E. c. MILLS 3,202,089

SINGLE SHEET PRESSES Filed June 11, 1964 4 Sheets-Sheet 1 INVEN TOR ByuleMua fi:

45 PM, ATTORNEY;

1955 E. c. MILLS 3,202,089

SINGLE SHEET PRESSES Filed June 11, 1964 4 Sheets-Sheet 4 Fig.5. 3

20 3e L l 42 iiiiii 4o 39 35 -37 35 33; i i l INVENTOR 4% WM ATTORNEY 5 tures.

United States Patent 0 3,202,099 SINGLE Si'lllET PRESfiES Edward Cecil Mills, Clifton, Bristol, England, assignor to Western Board Mills Limited, South Wales, a British company Filed June 11, 196%, Ser. No. 374,497 Claims priority, application Great Britain, .ilune 17, 1963, 24,ti78/63 6 Claims. (@l. lull-214) This invention relates to single sheet presses as used in the production of board and other fibrous sheet material.

There are a number of problems involved in the construction of single sheet presses, such as the need to provide, for maintenance purposes, as much separation or daylight as possible between the press platen and the co acting member opposed thereto, whilst reducing as much as possible the actual working stroke of the press. Another problem is that of providing substantially uniform loading over the whole area of the platen whilst keeping the pressure applying equipment simple though reliable in character and economical to install and maintain, using the minimum force to move the platen quickly to the pressureapplying position.

Solutions of the above named and other problems are provided by an improved single sheet press according to this invention, which embodies a number of useful fea- For instance, one object of the invention is to provide a press which operates economically and accordingly the present invention provides a single sheet press which comprises a frame having a stationary press head; a platen mounted for vertical movement beneath said press head and adapted to be loaded with sheet material to be pressed, fluid pressure means adapted to lift said platen toward said press head to apply pressure to sheet material interposed between said platen and said head and means to ensure parallel movement of the loaded platen as it is raised to the pressure applying position.

Another object of the present invention is to ensure a parallel movement of the loaded platen as it is raised to the pressure-applying position. To this end the platen may be suspended at its opposite ends on members of a linkage system which is under the control of a single fluid cylinder means.

Further objects of the present invention are to increase the capacity of the press so far as concerns the size of material which can be handled, by making the press of sec: tional form, and to facilitate the initial assembling and replacement of the fluid cylinder units which apply pressure to the platen. Accordingly it is preferred to employ a press frame of sectional form, in which case the press head surface onto which the platen presses sheet material loaded thereon is constituted by the aligned roofs of tunnel openings in a plurality of laterally adjacent unit sections, a single platen being used within the daylight gap provided by the tunnels of the collateral unit sections.

The need to reduce as much as possible the actual working stroke of the platen--whilst allowing as and when required the lowering of the platen to afford ample daylight-has already been referred to, and with this requirement in mind the improved press embodies simple stroke adjustment means for the platen.

Another feature of the improved press is that full pressure is not applied until the platen is pressing the load against the press head. Prior to this application of final pressure provision is made to keep moving components of a comparatively large number of cylinder units in close proximity to contact with, though applying little pressure to, the platen.

A sectional single sheet press embodying the features specifically referred to and incorporating means for solving the above mentioned problems will now be referred ice to, by Way of example, with reference to the accompanying drawings, but it will be understood that the invention in some of its various aspects, may be employed, possibly with some modification, to existing presses.

In the drawings:

FIG. 1 is a diagrammatic front elevation view, partly in section, of the press according to the invention.

FIG. 2 is a diagrammatic fragmentary end elevation of one of the unit sections of the press.

FIG. 3 is a vertical cross section through a press section, taken along line lll-lll of FIG. 2.

FIG. 4- is a plan View of two of the cylinder unit assemblies carried within each pressunit section,

FIG. 5 is a Vertical section through one of the fluid cylinder units,

FIG. 6 is a fragmentary sectional view, taken at right angles to FIG. 5, and

FIG. Tis a layout of hydraulic circuitry suitable for a sectional press constructed as illustrated in FIGS. 1 to 6.

The improved press diagrammatically illustrated in FIG. 1 comprises five collateral unit sections ll, 1A, 1B, 1C and 1D, which structurally are identical, the form of section 1 being shown by way of examplein FIGSZ and 3. The unit section comprises a Welded metal rectangular frame 2 with two parallel horizontal plates extending longitudinally and transversely therethrough, a base plate 3 and a top plate 4 which define the depth of a transverse through opening 5. These plates 3, 4 are held against defiection by webs 6 disposed between the plates and the opposing floor '7 and roof 8 respectively on the main frame 2. The section 1 is parallel-sided, so that a plurality of interchangeable sections, such as the five shown in FIG. 1, may be clamped together with the side faces in abutment, long bolts 9 passing through eyed lugs ill at the ends of the sections and long bolts 9A passing through guide tubes 11 provided centrally of. the collateral sections being used for clamping. v

When thus collaterally assembled the through openings 5 of the several sections l-lD combine to form a single tunnel 12 extending from front to rear of the sectional press and as the sections are of identical form the contiguous base plates 3 and top plates 4 combined to provide a single solid bed 13 and a firm head 14 for the press.

Within the tunnel 12 is situated a platen 15 of any suitable form. The platen 15 is adapted to be suspended within the tunnel 12 by hanging its opposite ends on rods 16 (at least one near each corner of the press) connected to hell cranks 17 mounted near opposite ends of the press.

Motion is transmitted to said bell cranks l7 and rods 16 to raise and lower the platen 15 by means of further rods 13 pivotably attached to opposite ends of centrally pivoted vertical movement of the platen 1.5 during normal working.

Beneath the suspended platen 15, resting on the several bed plates 3 of the unit sections, are a number of fluid cylinder units 23, conveniently six cylinder units in each press section, so that the five-section press of FIG. 1 employs no less than thirty cylinder units.

When the press sections are assembled the interior of the long tunnel 12 is not accessible for easy maintenance or replacement of a cylinder unit 23 situated beneath the platen l5 and accordingly apertures, 24 are provided in the opposite ends of the frame 2 of each section to give access to the through opening 5 of dissection at the level of base plate 3; it will usually suffice to have a centrally disposed aperture 24 at each end of the section. It is then convenient to insert a cylinder unit the use of high horsepower motors and pumps.

assembly 25 comprising a flat mounting plate 26 carrying three of the cylinder units 23 (FIG. 4) through one of the central apertures 24 and then bodily and laterally displace said assembly 25 out of line with the aperture to leave a clear way for another assembly.

The three cylinder units 23 forming an assembly 25 re conveniently connected in series by flanged connectors 23A so that a fluid line serving three cylinder units 23 needs only to be connected to a junction attachment 27 on an end cylinder. Each cylinder unit 23 (FIG. is of a simple sturdy construction and comprises essentially an upwardly-opening pot cylinder 28, and a ram 29 with a conventional form of sealing ring 30 at its lower end. It is preferred to use a spherical joint between the ram 29 and the ram cap 31 to ensure good contact with the underside of the platen 15. A bleed valve 32 (FIG. 6) is provided in each cylinder 23. To avoid weakening the Wall of cylinder 28 pressure fluid is admitted to said cylinder through a port 23A in the thick cylinder floor. Port 28A communicates with a cross bore 23B in the cylinder floor, and the cross bores 28B of the three cylinders carried on mounting plate 26 are aligned and interconnected by connectors 25A.

Hydraulic circuitry for a sectional press of the character described above can be of a simple character, because of the proposed mode of operation of the press. For instance, it has already been mentioned that the stroke of the suspended platen may be adjusted to a minimum, consistent with providing just suflicient space to load a board onto the platen. This loading may be and preferably is effected conventionally, and platen movement during normal working is small. When required, the rams 29 of the cylinder units 23 may be fully lowered so that a space of about three inches above the platen 15 is made available for inspection and cleaning purposes.

During normal working, fluid at low pressure may be supplied to the cylinder units which is nevertheless just sufficient to raise all the rams 29 so as to maintain contact with the platen 1-5 at all timesthat is, the rams until this position is reached. Contact of the board with t the press head 14 may be signalled in any suitable manner.

Consequently, the final pressure can be applied without Thus the hydraulic circuitry illustrated in FIG. 7, shows a pump set 33 capable of supplying 37.2 cubic inches per second at a pressure of 5000 lbs. per square inch, to provide the necessary full pressure, the said pump set 33 being associated with two high pressure eight gallon accumulators 34 (precharged to 3500 lbs. per square inch) and a pressurised hydraulic oil tank 35 to .240 gallon capacity (average air pressure lbs. per square inch). Oil under pressure may be supplied, via a twoway valve 36 to a main line 37 supplying up to thirty cylinder units 2 3, with 7% inch diameter cylinder bore and 3 inch rarn stroke-a total pressure area of nearly 2000 square inches.

The platen lift cylinder unit 2'1 is connected via a suitable four-way control valve 38 to the pump and accumulator feed line 41, and exhausts via discharge line 39 and non-return valve 4! The sequence of operation is, broadly, the raising of the platen 15 by means of the double-acting cylinder unit 21, which is operated from the accumulators 34 via valve 33; follow-up of the platen movement by the rams 29, due to pressure in oil tank change-over movement imparted to the spool of valve 36 when the board loaded on the platen 15 contacts the press head 14, resulting in the accumulators 34 discharging pressurised oil into the cylinder units 23 to raise the rams 29 thereof and thus apply full pressure to the board; reverse changeover of valve 36 to exhaust the system; operation of valve 3% to reverse the action of cylinder 21 to lower platen 15 and thus expel oil in cylinder units 23 via valves 36 and thence to tank 35.

Raising and lowering of the platen 15 may be efi'ected rather rapidly owing to the short stroke of the platen and because the weight of the platen is substantially counterbalanced by low pressure acting on the rams 29. A regulating pressure valve 42 may be placed in the feed line 4-1 extending between the accumulators 34 and the platen lifting cylinder 21 so that the most suitable operational pressures may be selected [and applied.

It is to be understood that dimensions and other qualitative values have been given simply by way of example and that these and modifications in structure may be made by those skilled in the art within the scope of the appended claims.

I claim:

1. A single sheet press comprising a frame having a stationary press head, a platen mounted for vertical movement beneath said press head and adapted to be loaded with sheet material to be pressed, fluid pressure means beneath said platen and adapted to apply pressure to said platen to lift said platen toward said press head to apply pressure to sheet material interposed between said platen and said head, means to ensure parallel movement of the loaded platen as it is raised to the pressure applying position and comprising a linkage system mounted on said frame and supporting said platen at its opposite ends, and a single fluid cylinder means controliing said linkage.

Z. A single sheet press comprising a sectional frame made up of a plurality of laterally adjacent unit sections, and having a stationary press head, a platen mounted on said frame for vertical movement toward said press, the surface of said press head onto which said platen presses sheet material loaded thereon being constituted by the aligned roofs of tunnel openings in said plurality of laterally adjacent unit sections, a fluid-pressure controlled linkage system supporting the said platen so as to lift the loaded platen with a parallel movement until it reaches a pressure-applying position, fluid pressure cylinder units beneath said platen for applying upward pressure to the platen on reaching said pressure applying position, and hydraulic pressure supply means coupled to said fluid pressure cylinder units for supplying fluid pressure to said units for applying full pressure to said platen by said cylinder units.

3. A press as claimed in claim 2, in which each tunnel of said sectional frame houses a plurality of fluid pressure cylinder units each including a pressure cylinder to follow up the ascending movement of the platen in readiness to apply full pressure quickly to the raised platen, and in which said supply means causes said fluid pressure units during this follow-up movement to apply at least only small pressure to the platen.

4. A press as claimed in claim 2 in which said plurality of fluid pressure cylinder units are in groups, and a common mounting for each group of units on which the group of units is mounted, each frame unit sect-ion having an aperture therein opening into the tunnel therethrough through which the groups of units on their common mountings can be inserted into the tunnel.

5. A press as claimed in claim 2 in which a plurality of the fluid pressure cylinder units are aligned, and are hydraulically connected to adjacent units in said plurality, and each has a floor with a cross bore extending diametrically of the unit through the floor and further has a port extending from the cross bore and opening into the interior of the cylinder.

6. A press as claimed in claim 1 in which said single 1,467,201 9/23 Sehriver 100--258 fluid cylinder means includes means for adjusting the 2,300,339 10/42 Camerota 100-258 Stroke of the piston thereof so as to adjust the stroke 2,446,823 8/48 Grant 100- 258 of the platen. r 2,627,289 2/53 Berthe'lsen t 144- 281 References Cited by the Examiner UNITED STATES PATENTS FOREIGN PATENTS 7,666 10/79 Germany.

10 WALTER A. SOH-EEL, Primary Examiner.

3,681,659 3/63 Francis 100-53 X

Claims (1)

1. A SINGLE SHEET PRESS COMPRISING A FRAME HAVING A STATIONARY PRESS HEAD, A PLATEN MOUNTED FOR VERTICAL MOVEMENT BENEATH SAID PRESS HEAD AND ADAPTED TO BE LOADED WITH SHEET MATERIAL TO BE PRESSED, FLUID PRESSURE MEANS BENEATH SAID PLATENT AND ADAPTED TO APPLY PRESSURE TO SAID PLATENT TO LIFT SAID PLATEN TOWARD SAID PRESS HEAD TO APPLY PRESSURE TO SHEET MATERIAL INTERPOSED BETWEEN SAID PLATEN AND SAID HEAD, MEANS TO ENSURE PARALLEL MOVEMENT OF THE LOADED PLATEN AS IT IS RAISED TO THE PRESSURE APPLYING POSITION AND COMPRISING A LINKAGE SYSTEM

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