US2553203A - Electrostatic sheet-perforating machine - Google Patents

Description

y 1951 L. J. MONTY ELECTROSTATIC SHEETPERFORATING MACHINE 2 Sheets-Sheet 1 Leo JZMo Filed Jan. 8, 1949 May 15 1951 L. J. MONTY ELECTROSTATIC SHEET-PERFORATING MACHTNE Filed Jan. 8, 1949 2 Sheets-She et 2 TO RAIL 34 Isa 29211302 To FRAME Zea Jib (b22350,

ayll/aan/vsmdtix fwwa/m FIG 5 flifomneys Patented May 15, 1951 ELECTRO STATIC SHEET-PERFORATING MACHINE Leo J. Monty,

Reading,

Mass., assignor to Goodall-Sanford, Inc., Sanford, Maine, a corporation of Maine Application January 8, 1949, Serial No. 69,891

Claims. 1

This invention has for its object to provide a machine for efiiciently, accurately, and rapidly electrostatically perforating non-conductive or di-electric sheet material and particularly coated fabrics such as largely employed for upholstery purposes.

The object of the invention is further to provide such a machine acting to produce the perforations without injury to the fabric, but of a character and size to render the fabric sunciently porous to breathe as that term is employed in the upholstery and allied arts, while at the same time the perforations are so minute as to be inconspicuous.

The object of the invention is further, and this is a most important feature, to enable the perforations to be formed in straight parallel rows spaced to any desired extent and extending transversely of the sheet of material. This, among other things, enables the number of perforations per unit of area to be controlled with exactness throughout the entire run of fabric.

The invention has for its further object to enable the perforating operation to be carried on at high speed with the perforations uniformly spaced in uniformly spaced parallel rows, and with each spark discharge formed under the same conditions, thus insuring the advantages of the electrostatic perforating operation to be secured.

Ihese and other objects and features of the invention will appear more fully from the accompanying description and drawings and Will be particularly pointed out in the claims.

The drawings illustrate a preferred embodi- 1 ment of the invention designed for the perforating of coated fabric, such as employed for upholstery and similar purposes, in which the fabric is of a width on the order of 54" and is handled in rolls of fifty yards or thereabouts, but the size of the machine and the Width and length of the sheet material operated upon depends upon the particular conditions.

In the drawings,

Fig. 1 is a top plan view of the machine with a piece of fabric passing through;

Fig. 2 is a front elevation of the machine with some parts broken away and some diagrammatically indicated;

Fig. 3 is a transverse vertical section taken on the line 3-3 of Fig. 2, looking toward the right;

Fig. 4 is a view on a smaller scale generally similar to Fig. 3, but illustrating a multisection machine; and,

Fig. 5 is a diagram illustrating a simple type of means for supplying to the machine the electric current for effecting the electric spark discharges.

The advantages of the electrostatic perforating of sheet material of various kinds are well recognized. The perforations formed in this manner, however minute they may be, still present, due to the burning operation, smooth finished wall openings enabling the passage of air or the breathing effect desired to be secured at all times.

While the machine of this invention may be employed with a wide variety of sheet material, it is particularly designed for use in the perforation of coated fabrics, such as employed in upholstery, Where it is important that a uniform breathing action to a controlled amount may be secured continuously and consistently in commercial operations. An important requirement in the securing of this result is that the number of perforations per unit area shall be uniform throughout and capable of adjustment as the particular character of the sheet material and the use to which it is to be put may deter mine.

In order to effect this result the machine of this invention operates to form the perforations in parallel, preferably straight, rows uniformly spaced to any desired amount, and extending transversely of the sheet of the material.

The essential feature of the machine for se curing the required results is the employment of two endless conveyers supporting and carrying the electrodes with one conveyer mounted above and one below the plane of travel of the sheet of material adjacent a point where it is firmly supported and with the lower run of the upper conveyer and the upper run of the lower conveyer guided to maintain the electrodes while on these runs in opposition and uniformly spaced so as to secure a uniform sparking action.

It will be seen that since the electrodes travel rectilinearly at a uniform speed, and the sheet of material travels in a direction at right angles to the path of travel of the electrodes, that the rows of perforations will always be parallel and extend at an angle to the edges of the sheet depending upon the relative speeds, that the rows will extend in straight lines when the electrodes and the sheet travel at the same speed, and that the spaces between the rows will depend upon the spacing of the electrodes on the conveyers and the relative speeds employed. The spacing of the perforations in each row will depend primarily upon the spacing of the electrodes on the conveyers, the speed of travel of the conveyers, and the speed of travel of the sheet.

Referring now to the specific embodiment of the invention illustrated the machine comprises a suitable supporting frame including the legs I and girders .2. A roll 3 of the sheet material 4 to be perforated is supported on a shaft 5 at the rear of the machine. Therefrom the sheet material passes forward over an idler roll 6, thence over a rectangular support, thenceover a second idler and is wound up by a driven roll 8 into a roll i} at the front of the machine. Any suitable means, such as the usual belt drive or independent motor, may be provided for driving the roll 8 which feeds the sheet through the machine at the required speed.

The rectilinear support over which the sheet 4 passes between the idler rolls E and l is for the purpose of maintaining the sheet taut in a plane extending transversely of the machine. Preferably, and as shown, it comprises two rigid rectilinear rails it extending in closely spaced parallelism so that the sheet 4 is held by them taut in a plane.

The conveyers employed are preferably sprocket chains. The upper conveyer H at the left of the machine extends around the sprocket wheel :2 on the shaft l3 and at the right around a sprocket wheel 14 carried by the shaft 5. The lower conveyer it at the left extends around the sprocket wheel ll carried by the shaft l8 and the right around the sprocket wheeel l9 carried by the shaft 28. The shafts i5 and 2c are idlers but the shafts i3 and i8 carry intermeshing gears and 22. The shaft i3 is shown as driven by a motor 23 acting through a suitable transmission mechanism 24 so that the speed of the conveyors may be controlled as desired.

Since the electrodes must be maintained uniformly spaced during the perforating operation it is essential that the lower run of the upper conveyer and the upper run of the lower conveyor shall be accurately maintained in uniformly spaced parallelism and parallel with the plane of travel of the sheet. This is easily effected in the case of the lower conveyer by providing a rigid transverse supporting rail 25 upon which the conveyor chain rests and travels while on its upper run. In the case of the upper conveyor a rigid rail 26, shown of L-shaped form, is secured to a rigid channel beam 2? extending transversely of the machine and suitably supported, as indicated, from the platform 2. The lower run of the conveyer ll rides on this rail 25 i and is preferably held in contact therewith by a series of idler sprocket wheels 28inounted on and extending forward from the beam 2'1.

An electrode 29 is secured to the lower conveyer 6 to project therefrom and is shown as a screw longitudinally adjustable in a block 33 secured to one link of the chain forming the cunveyer. The cooperating electrode 3! is similarly shown as a screw longitudinally adjustable in a block mounted on and projecting forwardly from one of the links of the chain constituting the conveyor i l. The electrode 3! extends into an angular suppor 33 which, while on the lower run of the conveyer, rides upon the flange of an angle iron 3 extending in parallelism with the rail 26 and supported from brackets 35 secured to the channel beam 27. The angle iron 3% is an electrically conducting rail and is therefore suitably insulated from the machine as, for example, by forming the supports 36 of Bakelite.

So also the block is of suitable insulating material. Hence the electrode 26 is insulated from the machine except when the angular support 33 is in engagement with the rail 34 or an extension thereof.

The electrodes 28 and 3| are thus carried during their passage across the sheet material directly opposite each other, held spaced at a predetermined constant distance. Any suitable and well known means may be employed for causing the sparking discharge between the electrodes with either alternating or direct current regulated by transformers, resistances, and condom-- and with the required frequency obtained either from the cycles of the alternating current or from the interruption of the direct current, as well understood in the art. Preferably the standard alternating current is employed with a condenser in the secondary circuit and a volt i eter therein for determining the transformed current, all as indicated in the diagram in Fig. 5. One branch of the secondary circuit is connected to the rail 34 which is insulated from the frame while the other branch is connected to the frame of the machine or the rail 25 which is secured to the frame.

The conveyers are shown as traveling in the d rection indicated by the arrows 3i and the rail .3

at the leading end is shown as having a curved :rtension 32 guiding the electrode 3! adjacent to a similarly curved plate secured to the frame so that sparking will begin shortly before the two electrodes come into alinement and thus insuring the sparking action beginning before the electrodes pass over the sheet of material.

The machine has been described with a single of conveyors and with a single pair of cora ug elec rodes, one on each conveyer, and this will be sun" ent for a large clas of work, but the speed of operation may be increased both by increasing the number of pairs of electrodes on the conveyors, by increasing the number of pairs of conveyers, or by both. A second pair of elect" des is indicated at 38 and ti in Fig. 2 and Fig. 4 is shown a machine in which the number of pairs of ccnveyers is increased, three such pairs of conveyors being illustrated as an exxnple.

It is unnecessary to describe in detail the multi section construction shown in Fig. 4 because it involves merely a duplication of the conveyers and their supports, the electrodes, etc. already described. As shown, the sheet of material 5 travels from the idler E31 over a plurality of rectangular supports 52 and thence over the idler Three lower conveyors 54 are shown carrying the electrodes 55, all guided and operating in the construction already described. So also three upper conveyors 59 carrying the electrode El are shown, all guided and operating already described. The right hand sprocket wheels 58 are ecured to a single shaft 59 corresponding to the shaft 2i! extended and similarly e upper sprocket wheels fill are secured to a sin s: shaft (ii corresponding to the shaft [5 extended. The drive at the left hand end of the machine not illustrated as it merely involves an extension of the shafts l3 and i8 and the duplication of the sprocket wheels thereon.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

l. A machine for electrostatically perforating sheet material comprising a rectilinear support, means for feeding sheet material across the support in contact therewith, rectilinear guides adjacent the support extending parallel therewith one above and one below the plane of the sheet travel, a pair of endless conveyers one above and one below said plane, with the lower run of the upper conveyer guided by the upper guide and the upper run of the lower conveyer guided by the lower guide, a pair of electrodes one projecting from each conveyer maintained by said conveyers and by said guides in opposition and uniformly spaced while on said runs, means for driving the conveyers, and means for causing predetermined electric spark discharges between the electrodes while on said runs.

2. A machine for electrostatically perforating sheet material as defined in claim I, in which the means for feeding the sheet material acts to feed the same at a uniform speed and the means for driving the conveyers acts to drive them at a uniform speed thus to insure the perforations to extend in parallel equispaced rows.

3. A machine for electrostatically perforating sheet material comprising a rectilinear support, means for feeding the sheet material across the support in contact therewith, a pair of endless conveyers one above and one below the path of the sheet material, means for driving the conveyers at the same speed, means for maintaining the lower run of the upper conveyer and the upper run of the lower conveyer in paths parallel to the support, a pair of electrodes one projecting from each conveyer maintained in cooperative relation while on said runs, and means for causing predetermined electric spark discharges between the electrodes whileon said runs.

4. A machine for electrostatically perforating sheet material as defined in claim 1, in which the upper electrode is mounted in a block projecting forward from the upper conveyer and is insulated from the conveyer, together with a current-conducting rail extending parallel to the upper guide insulated from the machine and upon which the upper electrode rides while upon the lower run.

5. A machine for electrostatically perforating sheet material comprising a plurality of parallel rectilinear supports, means for feeding the sheet material successively across the supports in contact therewith, a pair of endless conveyers i line with each space between the supports, with one conveyer of each pair above and one below the path of the sheet material, rectilinear guides for the lower run of each upper conveyer and the upper run of each lower conveyer, a pair of electrodes for each pair of conveyers, one projecting from each conveyer of the pair and maintained by said conveyers and their guides in 0pposition and uniformly spaced while on said runs, means for driving simultaneously all the conveyers, and means for causing predetermined spark discharges between the several pairs of electrodes while on said runs.

LEO J. MONTY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 736,571 Ball Aug. 18, 1903 1,898,014 Krumholz Feb. 21, 1933 2,011,645 Miller Aug. 20, 1935 2,277,942 Anderson Mar. 31, 1942 2,365,576 Meaker et a1 Dec. 19, 1944 2,372,508 Meaker Mar. 27, 1945 2,388,069 Meaker et al Oct. 30, 1945

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