US2645480A

US2645480A - Sheet delivery system for presses

Info

Publication number: US2645480A
Application number: US289295A
Authority: US
Inventors: Henry R Long
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-05-22
Filing date: 1952-05-22
Publication date: 1953-07-14
Anticipated expiration: 1970-07-14

Description

y 4, 1953 H. R. LONG 2,645,480

SHEET DELIVERYSYSTEMFOR PRESSES Filed May '22, 1952 2 Sheets-Sheet 1 F/G. f

INVENTOR HE NR) A. LONG ATTORNEYS July 14, 1953 LQNQ SF'IEE'T DELIVERY SYSTEM FOR PRESss 2 Sheets-Sheet 2 Filed May 22; 1952 INVENTOR HENRVRLONG BY ATTORNEYS Patented July 14, 1953 I UNITED STATES PATENT OFFICE SHEET DELIVERY SYSTEM FOR PRESSES Henry B. Long, Linden, N. J. Application May 22, 1952, Serial No. 289,295

This invention deals with a delivery system for delivering sheets from a press or other similar machine from which sheets are ejected in rapid succession. More specifically, this invention pertains to the use of a pneumatic'system for positive or pressure squeegeeing the top surface of each individual sheet ejected from the machine together with a simultaneous negative or vacuum squeegeeing of the bottom surface of the sheet.

At the present time the main limiting factor on the speed of a web-fed press, for example, is the Claims. (Cl. 271-74) speed with which the sheets leaving the press in sequence can be stacked after having been cut off by the knives. This is due to the fact that each sheet has a tendency to float in the air before settling into the stack, mainly because of the light weight of the sheet, and the air cushion underneath the sheet. Attempts have been made to speed the fall of the sheet by blowing air over the surface thereof. and it has been found from tests that some of the reasons therefor are the fact that it takes time for uniform leakage of air from under all of the surfaces of the sheet, and the fact that the air underneath the sheet is compressible and thus acts as a pneumatic pillow, keeping the sheet afloat for a definite period of time. reason, it is difiicult withpresent means to exceed a speed of about 30,000 sheets per hour with such delivery systems.

According to the present invention, a much higher delivery speed is efiected by rapidly applying a progressive air pressure wave which travels across the top of the sheet to produce a squeegee.

action, and simultaneously evacuating the air under the sheet in the same progressive manner, whereby the sheet is deposited on the stack in a very short period of time.

The invention may be more readily understood by reference to the accompany drawings in which Figure 1 represents a partially cut-away isometric view from the forward end of the delivery unit, connected with rotary pressure-vacuum actuating means. Figure 2 depicts the front end View (partially cut away), of the delivery unit shown in Figure 1, together with a cross-sectional view of the rotary valve, while Figure 3 illustrates a cross-sectional side View of the delivery unit together with a schematic side view of the cut-off roll and the pull-out rolls. Figures 4 and 5 illustrate schematically the pneumatic pressure and vacuum squeegeeing effects realized in the aforesaid units. Similar numerals refer to similar parts in the various figures.

Referring again to the drawings, numeral 1 represents a continuous sheet (e. g. or paper) be- This has not been satisfactory.

For this ing discharged from a machine (such as a web press). Cutting roll 2 from which projects cutting knife 3 is rotating at a speed synchronized with the speed of the machine (or press), and contacts stationary knife 4 so as to cut off sheet 5 which is of predetermined length for the finished sheet. Sheet 5 feeds into speed-up pull-out rolls 6 and l rotating in opposite directions and traveling at a higher speed than paper I and also provided with a slip clutch, so that when sheet 5 is gripped between rolls 6 and 1 it forms a slight separation of sheet 5 from the unsevered portion of paper I.

As rolls 6 and l eject sheet 5 into the delivery system, a blast of air is forced through parallel tubes 8 disposed across the lower width of sheet 5, said slip stream of air neutralizing any vacuum underneath the sheet caused by vacuum means (to be hereinafter described) as well as the aerodynamic eifect of the sheet travel, thus preventing it from prematurely sticking to stack 20 and lubricating the sheet as it is ejected into the delivery Zone 9-9. Immediately thereafter, air pressure is directed upon the top surface of sheet 5 (now 5) in rapid succession from rear to forward directions of the sheet by streams of air under pressure discharged through valves [0 into parallel distributor chambers II, the latter being disposed over parallel spaced channels l2 set at right angles to distributor chambers H. With this arrangement, the air is discharged through openings l3 between channels I2 in rapid succession as the air enters first valve M, then i5, etc. up to the forward valve I0, whereupon the procedure is repeated as the next sheet is cut off and enters delivery zone 9. V

Simultaneously, there is a vacuum being drawn progressively from rearward outlets l6, I7 and finally forward outlets I8 disposed at the sides I9 and beneath sheet 5, but above stacked sheets 20 in delivery zone 9 which contains the air resistance layer to be removed as the sheet 5' is being deposited on stack 20. A parallel row of. dischargevents 2| is provided along the Width of sheet 5 entering the delivery area, as well. The front end 22 of the delivery system preferably is a perforated sheet, such as a screen, in order to provide for adequate and efficient egress of air as the sheet 5 is being deposited.

The successive application of pressure blasts and vacuum may be accomplished by any suitable method, such as by solenoid valves at air inlets 0, l4, l5, l0, etc. and vacuum exhausts 2|, Ni, ii, iii, etc., or by a rotary valve one type of which is shown as valve 24 provided with separate pressure cell 3| and vacuum cell 32 connected to lines 21 and 28 leading to an air blower and vacuum pump, respectively. As

rotors

25 and 26 rotate on shaft 30 within housing 24 they provide successive access through chambers 31 and 32 to each air pressure outlet [4, l5, etc. and vacuum outlet l6, l7, etc. respectively, which are connected by conduits 33, etc. and 34, etc. respectively, providing the squeegeeing eifect heretofore mentioned. I'his squeegee effect may be more readily understood by referring to Figures 4 and 5. The successive blasts of air directed along the length of sheet from openings l3 as air is fed successively through valves M, then 15, etc. is analogous to a squeegee 35 which traverses the suspended sheet in the direction of delivery from rear to forward end (left to right) (Fig. 4) while simultaneously, vacuum applied to front 2| and side outlets successively It, then [1, etc. results in rapid evacuation of the resistant pocket of air under sheet 5, similar to squeegee 36, resulting in a rapid deposition on stack 20, first of theirear portion of sheet 5 enabling the succeeding sheet 5 to enter unhindered. By the time sheet 5 has reached forward end wall 22, sheet 5 has been completely stacked. By this means it is possible to obtain press speeds as high as 60,000 sheets per hour or even faster. 7

It is to be understoodthat line 33 represents a series of air pressure lines from pressure outlets 36, 37, etc. which are fed by air entering valve 26 through inlet 38, while line 34 represents a series of vacuum lines leading from

vacuum discharges

38, 39, etc., the vacuum being drawn from valve 24; through connection 39.

It is also understood that delivery platform 23 on which stack forms is, in accordance with conventional practice, automatically and gradually lowered at a rate predetermined with respect to the particular stock of sheet 5 run through the press, so that stack 23 is at all times lower than the plane in which single sheet 5 is ejected into the delivery zone 9.

It is also understood that rotary valve 24 is synchronized with the press and sheet size so that shaft 38 makes one revolution each time knife 3 severe a sheet of paper, plastic, or whatever sheet material is runthrough the machine.

Although one air blower and vacuum pump are disclosed herein, it is possible to use a number of such units as, for example, a pump for each side of the delivery system, etc. Valves I0 may be provided with regulating means 40 for adjusting the amount of flow of air into each distributor 4 ity and thus regulate proper air pressure over the entire top surface of sheet 5'. 7

It is apparent from Figure 2 that distributor chambers H are tapered along their length in proportion to the amount of air to be carried, so as to provide uniform air velocity through spaces or vents l3. In other words, distributor chambers II are of large cross, section near the air inlets l0 since this section must carry all of the air required to be forced through all of the vents l3. However, since the air is dissipated through vents I3 along the length of chamber II, the cross sectional area of the chamber is proportionately decreased to insure supply of the same amount of air through all of the vents thereunder. However, if air were introduced at both sides of distributing chambers I I, then the chambers would'be of equal cross-section at both ends.

In the operation of the system according to the present invention, sheet 5 is ejected by rolls 6-4 into delivery zone 9. As this takes place, the row of air vents 8 close to the rolls blow a slip stream of air under the sheet, thereby avoiding any possibility of sticking or curling down of the sheet. After sheet 5 (now sheet 5) has glided across delivery zone 9, its upper surface is squeegeed or massaged by pulses of air successively discharged from vents H3 in a forwardly direction as the air is fed in rapid succession from rotary valve 24 through valves 14, 1'5, etc. Simultaneously, the bottomof the sheet is negatively squeegeed by rapid withdrawal of air from zone 9' underneath chamber and, likewise, valves may be provided on the vacuum lines as well. As to two-chambered rotary valve 2 2, the rotor 25, fixed on shaft 3!) is provided with a continuous annular groove chamber L l connecting with air inlet 38. Rotor also has single discharge t! which feeds sue-- one to more readily watch the stacking operation.

Channels i2 may be removable and may be of varying width, so that air vents l3 may be made of varying size to enable control of the air velocsheet 5. This is accomplished by first applying vacuum at the roW of vacuum. outlets 2i thence at side outlets IS, IT, etc. successively from rear to forward position by means of rotary valve 24. Such an operation causes the rear portion of sheet 5 to be depressed first (as in Figs. 4 and 5), thus eliminating impedance to the next successive sheet which is treated in the same manner. When the latter sheet reaches forward wall 22 of the delivery zone, sheet 5' already is stacked. Perforated forward end wall 22 also facilitates egress of air from underneath sheet 5 due to its porosity.

One advantage of the present system is obtained by the fact that the delivery zone is completely enclosed, thereby eliminating cross-currents of air and excluding undesired gusts of air which might unbalance the regulated air streams and upset the stacking operation.

Although separate air pressure and vacuum systems are shown herein it is possible to insert nozzles in the air flow intakes at [0 through which air under pressure is blown into distributing chambers ll. When nozzles are employed, thereis a vacuum space immediately beyond the nozzle caused by the aerodynamic effect of the high speed air stream. A tube connection can be made from this zone to the vacuum inlets l6, l7, etc. to provide vacuum, thereby eliminating the need of a vacuum pump. In this case, the effect obtained is analogous to that in the atomizer where the :air stream causes sufficient vacuum to lift a column of liquid.

In. the case of the slip stream blast of air forced through outlet 8, it is preferred that this air stream be cut off momentarily when the air streams from outlets 14 are in operation.

I claim:

1. In a delivery method for stacking of light sheets injected in sequence at a continuous and rapid rate into a delivery zone, the improvement comprising injecting upon the entire upper surface of each sheet a rapid succession of air blasts a rapid successive application of vacuum along the front and at the sides immediately under said sheet in the direction of delivery. I

2. A delivery method according to claim 1 in which a slip stream of air is injected across and under each sheet prior to entry of each sheet into said delivery zone in amount sufficient to replace air evacuated therefrom.

3. A delivery method according to claim 2 in which vacuum is applied across and under each sheet after the pressure application prior to entry of said sheet into said delivery zone.

4. A delivery system for rapid stacking of light sheets injected in sequence into a delivery zone having a forward end, a rear end, and sides, comprising a series of air pressure distribution means disposed above the sheets for distributing pulses of air pressure across each injected sheet in rapid succession in the direction of delivery, a series of suction means at the sides of said zone immediately under said injected sheet for drawing vacuum in rapid succession in the direction of delivery and simultaneously with the pressure distribution on top of the sheet, intermittent air pressure and cut-ofi means for rapidly feeding air pressure and cutting it ofi in succession in said series of air pressure distribution means, and intermittent suction application and cut-off means for rapidly applying vacuum and cutting it off in succession in said series of vacuum application means.

5. A delivery system for rapid stacking of light sheets injected in sequence into a delivery zone having a forward end, a rear end, sides, and top, comprising a series of lateral air distributing chambers open at the bottom thereof and directed from side to side of said top over said delivery zone, an individual air inlet, in each of said distributing chambers to supply a pulse of air thereto, distributing means disposed under said distributing chambers for distributing equally the air discharged therefrom, a series of suction means disposed along the sides immediately :under the injected sheet, a row of suction means disposed in the rear portion of the delivery 6 zone for applying vacuum under and across each sheet prior to entry of said sheet into said delivery zone, intermittent air pressure supply means for supplying air pressure pulses in rapid succession through each of the series of distribution chambers in the direction of delivery upon the top of each sheet, and intermittent suction means for supplying vacuum in pulses in rapid succession through each of the series of suction means in the sides to evacuate the air progressively under each injected sheet.

6. A delivery system according to claim 5 in which the back of the delivery zone comprises a foraminous wall capable of allowing egress of air therethrough.

7. A delivery system according to claim 5 in which the intermittent air pressure sup-ply means and suction means comprise a rotary valve having separate compressed air outlets for each of the air distributing chambers, and separate suction connections to each of the suction means on the sides of the delivery zone.

8. A delivery system according to claim 5 in which a row of air pressure injecting means is disposed prior to entry of each sheet into the delivery zone for injecting a slip stream of air under each sheet in an amount sufficient to replace air evacuated therefrom.

9. A delivery system according to claim 5 in which each air distributing chamber is provided with an inlet control valve.

10. A delivery system according to claim 5, in which a nozzle is disposed for supplying a pulse of air into each distributing chamber and the intermittent suction means comprises a tube leading from the space immediately beyond each nozzle to each corresponding suction means.

HENRY R. LONG.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 923,085 Smith May 25, 1909 1,193,627 Staude Aug. 8, 1916 2,106,199 Wormser Jan. 25, 1938