US3476380A - Article actuated pneumatic separator - Google Patents

Description

Nov. 4, 1969 M. CALISTRAT 3,476,380

ARTICLE ACTUATED PNEUMATIC SEPARATOH Filed Dec. 15, 1967 2 Sheets-Sheet 1 FIG. I

46 FIG. INVENTOR.

34 Mme-A cAL/sreAT 26 I I BY Nov. 4, 1969 M. CALISTRAT ARTICLE ACTUATED PNEUMATIC SEPARATOR Filed Dec. 15, 1967 2 She ets-Sheet Z 7' III-P40 FIG. 4v

A R IIIIIIIIJ VIIIIIIII %R r /Y m FIG. 5C

INVENTOR.

M/PCEA CALISTAAT BY K12 6601.74

United States Patent O 3,476,380 ARTICLE ACTUATED PNEUMATIC SEPARATOR Mircea Calistrat, Pikesville, Md., assignor to Koppers Company, Inc., a corporation of Delaware Filed Dec. 15, 1967, Ser. No. 691,014 Int. Cl. B65h 1/06, 3/08 US. Cl. 27132 7 Claims ABSTRACT OF THE DISCLOSURE A pneumatic separator for separating a single sheet or blank from a supply for transfer to subsequent processing apparatus. The separator comprises a hollow, open-ended piston that slides within a continuously evacuated cylindrical sleeve which has resilient means for urging the piston outwardly against a stop limiting such outward movement. In its outward position, the piston engages the single lower Sheet or blank, thereby closing the end of the piston to atmosphere. The evacuation then causes the piston to withdraw within the sleeve to separate the article that is adhering to the piston from the supply and to position the article for transfer by associated transfer apparatus.

BACKGROUND OF THE INVENTION Field of the invention This invention relates generally to the feeding or delivering of sheet or blanks and more particularly to pneumatic separators for a multiple sheet supply.

Description of the prior art Suction means for separating single sheets or blanks from a supply have been of two types. They have been operative either (1) to lift the uppermost blank from the pack and advance or place it in position for advancement by associated transfer means or (2) to separate the bottommost blank from the pack for similar advancement. The latter type is particularly useful in separating blanks which are warped in either the direction of advancement or transverse thereto or both.

The types which lift and/or advance the uppermost blank are usually provided with suction cups which are mechanically moved by suitable linkages into engagement with the top blank of the pack whereupon the suction cups adhere to the blank and separate it from the pack as the cups are retracted. The cup may, itself, pivot to advance the adhering blank or a separate pusher element may thereafter advance the blank. In either event, it is usually necessary to provide means, such as valves, to break the vacuum between the cup and the blank to permit advancement. Devices of this type are subject to considerable wear because of the number of moving parts and the production speeds at which they must operate. Spiess Patent No. 3,000,629 illustrates a vacuum cup utilizing two suction zones, both of which are evacuated for separation of the topmost blank from a pile. When the blank has been raised to the transfer position, vacuum is broken to the stronger of the suction zones by closing the entrance port to the zone by bottoming a piston within its casing or sleeve.

On the other hand, suction devices operative to separate the bottommost blank from a pack are usually of the fixed type; i.e., a vacuum port is provided in the bed-plate which supports the pack. If the blanks of the pack are warped, they do not lie flat against the bed-plate so it is diflicult to transfer or feed the blanks sequentially through a metered opening in register with associated processing machinery. Fixed suction devices are helpful in drawing the warped blanks against the bed-plate but they are not always positive so that jam-ups can occur when the trans- 3,476,380 Patented Nov. 4, 1969 ice fer device attempts to feed a blank through the metered opening. An example of this type suction device is found in Bishop et =al. Patent No. 3,105,681 which also uses a reciprocable suction device to separate the lowermost blank from the pack and advances the blank through a metered opening.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a pneumatic separator actuated by the blank to be separated from a pack which is both simply constructed and reliable. Complex valving arrangements are not necessary to break the suction force between the separated blank and the pneumatic separator. This is generally accomplished by providing an open-ended piston slidably nested within a cylindrical casing or sleeve and having resilient means for urging the piston outward from the sleeve, and into subatmospheric engagement with a blank to be separated from a pack. Evacuation means are provided for automatically creating a suction within the piston upon its engagement with the blank which is operative to telescope the piston within the sleeve thereby drawing or separating the blank from the pack. The invention is operative in conjunction with conventional adjacent transfer means for feeding the separated blank through a metered opening and into subsequent processing machinery.

The above and further objects and novel features of the invention will appear more fully from the following detailed description when the same is read in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are not intended as a definition of the invention but are for the purpose of illustration only.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings wherein like parts are marked alike:

FIGURE 1 is a side elevation in cross-section of the pneumatic separator showing the piston engaging the lowermost blank of a pack prior to separation;

FIGURE 2 is similar to FIG. 1 and shows the lowermost blank subsequent to separation from the pack but prior to feeding or transfer through a metered opening;

FIGURE 3 is a cross-section of the pneumatic separator taken along the line IIIIII of FIG. 1;

FIGURE 4 is an end elevation of a series of the pneumatic separators engaging the lowermost blank which is shown warped transverse to the transfer or feed path of the blank;

FIGURES 5A, 5B, and 5C are schematic illustrations of the sequence of operation of the separators during a typical feed cycle; and

FIGURE 6 illustrates an optional locking feature to deactivate the separator.

DESCRIPTION OF THE PREFERRED CONSTRUCTION The novel pneumatic separator assembly 10 is illustrated in FIG. 1 as being associated with a conventional packsupporting bed-plate 12 adjacent the forward or leading edge 14 of the lowermost blank 16 of pack 18. A conventional gate 20 above the bed-plate 12 is vertically adjustable in the known manner to define a metered opening 13 of the required size between the gate 20 and bed-plate 12 to permit only one blank at a time to pass therethrough. As shown in FIG. 5, the blanks of pack 18 are often warped in the direction of feed of the blanks, and the leading edges 14 of the blanks that rest against the face of gate 20 are likely to be spaced above the top surface of bed-plate 12. Any attempt to feed the lowermost blank 16 through the metered opening 13 without employing the novel separator assembly 10 will merely jam the leading edge 14 into the face of gate 20.

The separator 10 of this invention draws the leading edge 14 of lowermost blank 16 downward against the top surface of bed-plate 12, as illustrated in FIG. 2 so that the feeding mechanism will engage the trailing edge of the blank and advance it through opening 13 until it is gripped by a pair of pull rolls 22, as seen in FIG. C. Rolls 22 advance the blank into adjacent processing machinery (not shown). When the trailing edge of the lowermost blank clears the separator 10, the separator is again operative to draw the next lowermost blank downward against the fbed-plate 12 and the sequence is repeated.

Referring now to FIGS. 1 and 3, separator comprises a tubular piston 24 that is open on both ends and is slidably positioned within a casing or sleeve 26. Sleeve 26 is secured in any convenient manner such as, for example, by a press-fit in a hole 28 in bed-plate 12. The upper end of sleeve 26 is preferably flush with the top surface of bed-plate 12. The lower end of sleeve 26 is joined to a transverse duct or header 30 by, for example,

welding. A hole 32 is provided in header 30 so that a path is provided for the flow of air from the upper end of piston 24' into header 30.

A tension spring 34 urges piston 24 upwardly against the lowermost blank 16. Spring 34 is provided with conventional end loops 36 which surround an upper pin 38 and a lower pin 40. These pins 38 and 40 are preferably provided with reduced diameter reliefs 48 to retain spring 34 centrally within piston 24. As best illustrated in FIG. 3, lower pin 40 is positioned in a pair of diametrically aligned holes 42 in piston 24, and upper pin 38 is positioned in a pair of diametrically aligned holes 44 in sleeve 26 so that it remains fixed. Pin 38 extends through a pair of diametrically aligned longituidnal slots 46 provided in piston 24. The tension of spring 34 pulls pin 40 upward, carrying the piston 24 with it, to the position shown in FIG. 1. If no blanks are lying on bed-plate 12, the piston 24 will extend upward until pin 38 bottoms in slots 46.

Of course, other means may be utilized to urge the piston upward against the lowermost blank. For example, a coil compression spring of approximately the same diameter as the piston 24 may be placed between the piston 24 and the header 30. Another example is a metal bellows of approximately the diameter as the piston 24 placed between the piston and the header.

The sleeve 26 is preferably made of metal. Although the piston 24 may also be made of metal, it is preferably made of a rigid plastic such as plexiglass so that if any accidental breakage occurs, the piston will break rather than the sleeve. The pistons are relatively inexpensive and may be easily replaced.

The blanks may be warped transverse to the direction of advancement as illustrated in FIG. 4. So that the leading edge 14 of blank 16 will be drawn against the bedplate 12 beneath the gates 20, of which there are usually two, it is preferable to provide a separator 10 in longitudinal alignment with each gate. Since the gates are transversely adjustable to accommodate wide blanks, as shown by the phantom lines in FIG. 4, two more separators may be provided in alignment with the outward positions of the gates. When the outermost separators are not being used, as when narrower blanks are fed, a. scrap piece of paperboard can be placed over them to prevent the loss of suction. The suction will maintain the pistons 24 in the down position without the need for fastening the scrap paperboard to the bed-plate 12.

The sleeve 26 of each separator 10 may be joined to header 30 as previously described. A conventional electrically operated blower 50 is connected to the header 30 in the ordinary manner to provide a vacuum therein and consequently in the sleeves 30, The amount of vacuum or suction is preferably equal to about four inches of water although as little as three or as much as eight inches will operate the separators 10 in a satisfactory manner when the blanks are ordinary corrugated paperboard. At less than three inches of water, the suction may be insufficient to insure that the leading edge 14 will be drawn down completely against the bed-plate 12. At more than eight inches, it becomes diflicult to slide the blank across the top of the separator 10. It should be understood that the suction pressure can be changed to suit the need when separating blanks of other materials.

The transfer or feed mechanism illustrated schematically in FIG. 5 is of a conventional reciprocating type. The feed mechanism as illustrated herein is, for example, the type described in Schulz Patent No. 3,038,720 wherein a number of back-stops 52 are spaced across a transverse bar 54 to support the trailing edges of the pack 18 above the bed-plate 12 and to provide a space beneath the pack for reciprocating spring feeders 56 that include lip portions 60 adapted to engage the trailing edge of the lowermost blank when the feeders are in the rear position. The bar 58 supporting the feeders 56 is reciprocated in the conventional manner. Both bars 58 and 54 can be positioned toward and away from the gate 20 to provide for different length packs.

In operation, as seen in FIG. 1, the tension of spring 34 urges piston 24 upwards until it engages the bottom of the lowermost blank 16. The blank 16 closes the end of piston 24 to atmosphere. Suction pressure in sleeve 26 and piston 24 overcomes the slight tension in spring 34 so that piston 24 is drawn downward and within sleeve 26, drawing blank 16 with it to the position shown in FIG. 2. At this time, the feeders 56 are advanced in the normal manner thereby pushing the blank forward, as seen in FIG. 5C, until it is gripped by the pull rolls 22. The pull rolls continue to advance the blank as the feeders 56 return toward the feeding position, FIG. 5A. Concurrently, piston 24 will again rise as the advancing blank clears it since the top of the piston is again open to atmosphere. As soon as the piston 24 engages the next lowermost blank, it will draw it downward, as previously described, to the feeding position, FIG. 5B, Thereafter, the cycle is repeated.

In ordinary suction devices, it is usually necessary to break the suction between the blower, or vacuum pump as the case may be, and the blank engaging member to permit the blank to be advanced. This need usually requires the use of complex valving or venting arrangements which are subject to wear. The present invention does not require these. When the piston 24 approaches the lowermost blank, even a low suction pressure is sufiicient to draw the .blank downward against it, even if the blank is not parallel to the top of the piston, see FIG. 1. When the blank is drawn against the bed-plate 12, the pressure acting on top of the blank merely presses it against the bed-plate. The only pressure between the blank and the piston is the slight amount needed to overcome the tension of spring 34. Thus, the piston is subject to very little wear. The difference in pressure reacts only between the bed-plate and the blank. This pressure is easily overcome by the feeders 56 which slide the blank across the upper surface of the bed-plates. Since the blank is pressed against the large surface of the fbed-plate 12, no unwanted scuffing of the blank will occur.

FIG. 6 illustrates a locking feature to deactivate piston 24 which may be used should it be desired to operate the feeder without the use of a vacuum or with the vacuum as an assist but without the pistons. The lock comprises a circumferential slot 62 formed at a right angle to the top of each slot 46 as illustrated. Thus, by depressing the piston 24 and giving it a slight twist, slot 62 will be positioned over the pin 38 and prevent extension of the piston. The tension of spring 34 maintains the piston in the locked position. Twisting the piston in the opposite direction will unlock it.

Thus, the present invention provides a simple, positive-operating pneumatic separator which is actuated by contact with the blank. Because of its construction, very law suction pressure is required. It is subject to very little wear since the sliding friction between the piston 24 and the blank is reduced by the suction pressing the blank against the bed-plate 12 rather than against the piston. The piston, because of its construction, has a very small mass, hence. a low inertia, so that it operates rapidly. For example, in actual commercial use, four separators of the type described herein have operated successfully in a printer-slotter machine feeding blanks at the rate of four per second with a suction pressure equal to four inches of water while requiring only two horsepower to operate the blower to displace approximately eighty cubic feed of air per minute per piston.

Having thus described the invention in its best embodiment and mode of operation, that which is desired to be claimed by Letters Patent is:

1. Apparatus for feeding blanks sequentially from a supply of such blanks, comprising:

a support for said supply of blanks;

gate means defining a metered opening with said support for limiting the feeding of blanks therethrough to one blank at a time; suction means in said support for separating a single blank from the bottom of said supply and positioning the leading edge of said blank against said sup port for entry into said metered opening; and

reciprocating advancing means for engaging the trailing edge of said blank to advance it through said metered opening.

said suction means including a tubular piston having one end in communication with an air evacuating means and a blank engaging end, resilient means for biasing said piston toward said supply so that said piston is closed to atmosphere by engagement with said single blank causing it to adhere to said piston and causing said piston to move toward said one end.

2. The apparatus of claim 1 wherein said suction means includes a sleeve, said tubular piston lying within said sleeve and said resilient means urging said piston to extend beyond the end of said sleeve into engagement wit-h said supply and said piston being adapted to telescope within said sleeve when said blank engaging end is closed to atmosphere by said blank, said air evacuating means operative to hold said blank against said sleeve when said piston is telescoped within said sleeve.

3. The separator of claim 2 wherein said resilient means includes:

a first member connected to said sleeve and held in a fixed position thereby;

a second member connected to said piston and movable therewith; and

spring means connected to said first and second members for urging said second member toward said first member for extending said piston beyond the end of said sleeve.

4. The separator of claim 3 wherein said first and second members are pins secured in diametrically aligned apertures in said sleeve and said piston, said piston including diametrically aligned axially elongated slots in the wall thereof through which said first member ex tends providing a stop to limit the extension of said piston beyond the end of said sleeve.

5. The separator of claim 4 wherein said elongated slots include a transverse slot formed in said piston substantially perpendicular to one end of said elongated slots adapted to receive said first member when said piston is rotated in the telescoped position to retain said piston in said telescoped position.

6.'The separator in claim 1 wherein said piston is made of a rigid plastic material.

7. Apparatus for separating a single corrugated blank from'the bottom of a stack of blanks and transferring it to subsequent processing machinery comprising:

a bed plate for supporting said stack of blanks;

a gate mounted above said plate a space of one blank to limit the movement of said stack so that only one blank at a time can pass through said space,

feed means at the rear end of said blanks and opposite from said gate for engaging and urging the lowermost one of said blanks through said space,

said blanks being susceptible to warping whereby the front end of said lowermost one of said blanks that is adjacent said gate lifts from said bed and said blank tends to jam against said gate instead of passing through said space, and

suction means for pulling the front end of said blank against said bed to insure passage of said blank through said gate including:

an aperture in said bed adjacent said gate, a piston reciprocal in said aperture, resilient means urging said piston to extend through said aperture and into engagement with the front end of the lowermost one of said blanks whereupon the end of said piston becomes closed by said blank, and suction means operable upon the closing of said piston for retracting said piston into said aperture to pull the front end of said lowermost blank against said bed, whereby the urging of said feed means will pass said lowermost blank through said space between said gate and bed.

References Cited UNITED STATES PATENTS 906,827 12/1908 Staude 27l-44 EDWARD A. SROKA, Primary Examiner US. Cl. X.R. 27 l44

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