US2862707A - Sheet transfer apparatus - Google Patents

Description

Dec. 2, 1958 R. G. vo?sEY SHEET TRANSFER APPARATUS Filed Nov. 29, 1955 A T T OFLl 5Y8.

2,862,707 SHEET TRANSFER APPARATUS henna George v'tsyse London, England, assignor to Peter Carmichael and Company Limited, London, England, a British company Application November 29, 1955, Serial No. 549,762

Claims priority, application Great Britain December 1, 1954 3 Claims. (Ci. 271-3) This invention relates to sheet transfer apparatus of the kind in. which. sheets or blanks of paper (hereinafter called blanks). or the like are passed through a machine on a number; of transfer members; such as rotary cylinders; on the surface of which they are held by suction applied. from. inside the cylinder through orifices in the cylinder-wall.

Such apparatus is used: in automatic envelope making machinery where envelope blanks are carried from stage to stage on a series of cylinders and is also used in printing;andothermachineryt. The blanks: are usually fed to the first cylinder from a wad orv stack, but they maybe cut by the; machine from reels of paper and then be fedlto the, first cylinder Difiiculties havehitherto been encountered when the feeder failsgto feed blanks to the firsbcylinderor-whenv a, blank becomes misplaced, or

apthe beginning andend of a run as the suction orifices in some of the cylinders are thenuncovered, and thus allow-gait, tocnter the system with the result that the' consequent fall inthevacuum in the main supply line "makes itdifiicult or impossibleto handle. the blanks.

Theoretically, this difficulty could be overcome by the proyisionofa vacuum pump or'pumps having sutficient capacity-tocope with; the worst'conditions to which the apparatus might be subjected and yet to maintain the vacuum at a high enough level to permit the blanks which do pass through .the, apparatus to be handled satisfactori- 1 However, thisis-not always commercially parcticable because the cost of providing satisfactory vacuum-producing devices on machines dealing with large or heavy sheets of paper is prohibitive, and alsobecause the size of thejvacuum;'producingrequipment would be too great.

various wayslhave been proposed for overcoming this diificiiltyibu't. none of them has proved completely satis- V factory 'or capable of, universal application.

It .isjnyobjec't'of .tl'iepresent inventionto provide an improved apparatus which does enable blanks to be handled satisfactorily wat slow or high speeds, at the beginning afid'fe'nd 'of a run; and if the flow of blanks passing tion suction apertures which are'larger than the ones used in known apparatus thus giving more positive holding capacity than has hitherto been possible, Without a corresponding increase in the sizeof the vacuum producing'equipment;

It'isyet another object of the invention to provide a meansof-picking up information from a blank in one section of a machineand sending that information forwardaheadiof the blank,.in order to'prepare a following station for the arrival of the blank-.;

Accordingly, the invention provides a blank transfer United S ttes Patent apparatus comprising a movable transfer member on which blanks can be held by suction applied to the interior of the member so as to act on the blank through orifices in the transfer me'mber'and a trigger valve which is responsive to the pressure inside the transfer ,rr 1emher and is adapted to control the application of suction to another part of the apparatus, the said valve being automatically opened by the decrease in pressure produced inside the transfer member when a blank is held thereon.

According, to another aspect, the invention provides a blank transfer apparatus which comprises a plurality of movable transfer members adapted to hold blanks by internally applied vacuum, wherein each of the transfer members is connected directly with a source of vacuum, the connection to the first member including means for maintaining vacuum at a desired level while the apparatus is in operation and the connection to each other transfer member being controlled by a trigger valve which isnormally closed but which is automatically opened as a previous member passes a pre-selected position if that previous member is carrying a blank.

If the previous member carries no blank, the trigger valve controlling the following cylinder will close or remain closed as the case may be. 7

It will be appreciated that any desired number of transfer members can be employed and that each station need not be a transfer station, but could be a printing, counting, folding or cutting station or the like.

The trigger valve or valves can be opened or maintaiued in the open position by the-vacuum to which the valve or valves is or are directly connected when a'preceding transfer member reaches the appropriate'position, only if'that member is carrying a blank. However,- if the previous member carries no blank, air at atmospheric pressure will be admitted to the head of the trigger valve which will then close or remain closed as the case may be and so prevent leakage of air into the'system.

A preferred embodiment of the invention is illustrate in the accompanying drawing which is a diagram of a transfer apparatus for handling envelope blanks in envelope-making machinery in a condition where the sequence ofoperations has been interrupted by the failure of a blank to feed. 7

The apparatus illustrated comprises a number of transfer cylinders 1, 2, 3, 4 and 5 which are rotatable about horizontal axes, the blanks B being fed from a wad W and held on the cylinders by internally applied vacuum acting on the blanks B through orifices O in .the walls of the cylinders. In operation, the blanks may be passed from the curved surface'of one cylinder to another right through the apparatus, but, if desired, folding devices or the like may intervene. in the drawing, all parts under vacuum are shaded.

The first cylinder 1 contains a fixed arcuate manifold 6 having an opening on one side which is closed by the perforated Wall of the cylinder 1 so that suction will be applied through the orifices 0 (only one of which is shown) when they are brought in communication with the fixed manifold 6 as the cylinders rotate. This manifold 6 is directly connected with a main 7 in which a constant vacuum is maintained by a vacuum pump (not shown). In a supply pipe 8 connecting this cylinder 1 to the main 7 is fitted a regulator 9 for limiting the flow or air in the pipe 8 to a desired amount at this point so that itis possible to maintain high vacuum in the main 7 and low vacuum in the cylinder 1 itself when the orifices O of'the cylinder are open to' atmosphere and not covered by an envelope blank. This is necessaryin .order to obtain a pressure diiferential for the operation of a first trigger-valve ashereinafter described -This fiow regulator 9 can be of any suitable type, such as an adjustable needle valve or a simple ring orifice, and is preferably so adjusted that a vacuum of to 17" Hg is always maintained in the main 7 and a vacuum of approximately 3" Hg in the cylinder 1 itself when its orifices O are not covered. The amount of air passing the flowregulator 9 will be so restricted that it is possible to vary the number or size of the suction orifices in the first cylinder 1 without affecting the vacuum in the main 7. This may be needed when dealing with blanks of various widths.

A second supply pipe 10 extends from the main "7 to a fixed arcuate manifold 11 in the second cylinder 2. This arcuate manifold 11 is of similar construction to the one in the first cylinder. The second supply pipe 10 includes piston begins to move under suction applied from the previous cylinder, vacuum at full line pressure passes through the hole in the direction of piston movement and acts as an accelerator to pull the valve into its full stroke position. When the valve has come to rest, the presence of this hole prevents any danger of the valve resetting due to premature loss of vacuum seal in the preceding cylinder.

Each cylinder also includes a conduit 13 (shown in chain dotted lines) which rotates with the cylinder and communicates directly with the orifices 0.

Each fixed manifold also includes a port 19 open to atmosphere to ensure a complete breakdown of the vacuum in the rotatingarcuate manifold 13 at instant of transfer.

When a blank B is fed from the wad W or stack on to the first cylinder 1, the vacuum in the cylinder rises to full line vacuum as the suction orifices O are closed by the blank B. When the cylinder 1 has rotated a preselected amount, the rotating conduit 13 will bridge the fixed arcuate manifold 6 and a passage 14 leading to one side of the trigger valve 12. As a result of this, vacuum at full line pressure is applied directly to one side of the piston 12]; of the trigger valve 12 from the main 7 so that the valve is opened to permit vacuum to be applied directly to the arcuate manifold 11 in the second cylinder 2. Further rotation of conduit 13 isolates the passage 14 and leaves the trigger valve in the position established by the condition of the vacuum in the cylinder trigger valve 12 which will therefore close or remain closed as the case may be.

The fixed manifold 11 and the rotating conduit 13 -in the second cylinder are so arranged that none of the suction orifices O of the second cylinder 2 is connected to vacuum until the envelope blank B is about to be transferred to it from cylinder 1. Conduit 13 then engages with the fixed manifold 11 and the orifices are provided with suction to hold the blank in position on the cylinder 2 and as the blank leaves the first cylinder 1 the supply of vacuum to the orifices O in that cylinder is cut ofi by the rotating conduit 13 disengaging from the arcuate manifold 6 and connection to atmosphere is established an instant later .when the rotating conduit 13 passes over a port 19.

The second cylinder 3 is also associated with a trigger valve 16 controlling a third supply pipe 17 leading directly from the main 7 to a fixed arcuate manifold 18 in the third cylinder 3 so that the sequence is repeated as the blank moves forward on the second cylinder 2. In the diagram, the trigger valve 16 is shown in its cutoff" position as cylinder 2 carried no blank on its previous revolution. The trigger valves will automatically remain in the open or run position as long as a continuous supply of blanks is fed to a preceding cylinder, and only move out to cut ofi the vacuum when a sheet is missed.

This sequence is repeated for any desired number of cylinders.

It will be appreciated that the apparatus provided by the present invention has many advantages over those previously known. When no blanks are passing through the machine only the first cylinder 1 is directly connected with the main 7 and the amount of air that can flow in that cylinder is controlled; thus the pressure in the main can be set and held approximately constant at any desired level irrespective of the number of suction points in the machine. Each vacuum station has its own individual cut-off or trigger valve which is operated solely by the presence or absence of a blank on the preceding cylinder.

As soon as the flow of blanks is interrupted, the trigger valves reset to cut off each station in turn and prevent leakage of air into the system. This arrangement permits blanks to be handled in an equally positive manner at low or high speeds irrespective of whether or not the feeding mechanism misses the feed of a blank or blanks, or the operator removes a blank for inspection, as may be done to check printing or gumrning, and also at the beginning and end of a run.

This arrangement also permits the size or number of suction orifices in all or any of the cylinders to be varied to suit the work in hand. Such variation' in no way hinders the working of the device and no adjustments to compensate are needed.

It will be understood the invention can be used for the control of a complete machine or of only a section or sections of a machine.

By making use of the resetting movement, of the tn'gger valves it is possible to incorporate step by step cut outs to stop the apparatus if a blank fails to pass any of the transfer points. Such a cut out has positive action, does not involve touching the paper and cannot be upset by paper conditions, vibrations etc. It also makes possible stage by stage cut-out control in a very simple manner.

If desired, a trigger valve can be used to control the application of suction to a part of the apparatus other than a transfer cylinder, e. g. a suction-operated printing cylinder.

In another modification, the first trigger valve in the apparatus is operated by an electrical solenoid energized in response to a detector switch when the first sheet enters the apparatus. This replaces the regulator or throttle device 9, but the subsequent trigger valves are suctionoperated. This device eliminates entirely all leakage of air into the system.

Automatic cut outs may be incorporated in each trigger valve to stop the apparatus when a blank fails to pass.

What I claim is:

1. A blank handling apparatus comprising a series of suction-operated blank handling devices at least some of which are blank transfer members on which blanks can be held by means of suction applied to the interior of said members and acting on said blanks through orifices in said members, a source of suction, a plurality of connections each of which connects one of said handling devices directly to said source, a plurality of trigger valves one of which is located in each of said connections except the connection between said source and the first handing device in said series, each of said trigger valves normally closing one of said connections but being responsive to pressure in one of said transfer members at a previous position in said series so as to open automatically when a blank is handled by a transfer member at said previous position.

2'. A blank handling apparatus comprising a series of blank transfer members over which a blank can pass in sequence, each of which members has an orificed surface, a vacuum source, a plurality of connections each of which connects the interior of one of the transfer members to said source of vacuum independently of the other member, so that blanks can be held on said orificed surfaces, means between the first transfer member in said series and said source of vacuum for maintaining the vacuum in said first transfer member at a desired level while the apparatus is in operation, and a plurality of trigger valves each of which controls a connection between one of said transfer members other than said first member and said source of vacuum, each of said trigger valves being normally closed, but responsive to pressure inside one of said transfer members at a previous position in said series so as to be automatically opened if the pressure in said previous one of said transfer members is caused to fall by the travel of a blank on that previous cylinder.

3. A blank handling apparatus comprising a plurality of seriately arranged blank transfer members each having an orificed surface, a vacuum source maintained at a substantially constant level of pressure, a connecting line i for each of said cylinders for connecting each cylinder directly and independently to said source, pressure regulating means connected in the connecting line of the first of said transfer members for maintaining a vacuum within said first member which is relatively low compared to that of the source when no blanks are being transferred.

on said first member, said pressure regulating means permitting the vacuum in said first member to increase to substantially equal that of the source when blanks are being transferred thereon, a plurality of piston valves each connected in the connecting line of each succeeding transfer member and adapted to move between an open and a closed position, means biasing each valve toward its closed position, valve actuation means connecting each piston valve to the immediately preceding transfer member in series and adapted to open said valve when the vacuum in said immediately preceding member substantially equals that of the vacuum source and to maintain said valve open as long as the vacuum in said immediately preceding member is thus maintained.

References Cited in the tile of this patent UNITED STATES PATENT 8 1,408,688 Broadmeyer Mar.'7, 1922 1,418,145 Fischer May 30, 1922 2,686,052 Winkler et a1. Aug. 10, 1954

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