US3510126A

US3510126A - Mechanism for feeding a sheet material to a processing machine

Info

Publication number: US3510126A
Application number: US656553A
Authority: US
Inventors: Victor Romanens
Original assignee: J Bobst et Fils SA
Current assignee: Bobst Mex SA
Priority date: 1966-07-29
Filing date: 1967-07-27
Publication date: 1970-05-05
Anticipated expiration: 1987-05-05
Also published as: FR1532871A; ES343939A1; BE701784A; GB1150256A; DE1611341B1; SE331023B; CH440337A

Description

5, 1970 v. ROMANENS 3,510,126

MECHANISM FOR FEEDING A' SHEET MATERIAL TO A PROCESSING MACHINE Filed July 27, 19s? 2 Sheets-Sheet 1 FAVOR ART 5 ZQZZ IL \Ik\1l \\lll\ TIL O 0 0 1 00000 ooooo o 00 I/ 5 @oo o 00 E F 00000 T PIP/0r? ART May 5, 1970 v. ROMANENS 3,510,125

MECHANISM FOR FEEDING A SHEET MATERIAL TO A PROCESSING MACHINE Filed July 27, 1967 2 Sheets-Sheet 2 I\\HF\\\ h m I n K /6 -H i 2/7 /6 E &

l/% "'J. lll' F 6. 5 /f 1f J- I l a 2/4 United States Patent 3,510,126 MECHANISM FOR FEEDING A SHEET MATERIAL TO A PROCESSING MACHINE Victor Romanens, Prilly, Switzerland, assignor to J. Bobst and Son S.A., Prilly, near Lausanne, Switzerland, a corporation of Switzerland Filed July 27, 1967, Ser. No. 656,553 Claims priority, application Switzerland, July 29, 1966, 11,085/66 Int. Cl. B65h 1/06 US. Cl. 27132 11 Claims ABSTRACT OF THE DISCLOSURE A mechanism in which a reciprocal carrier member adapted for holding a sheet of material thereagainst by suction is provided with a displaceable member which projects from the carrier member under a first differential suction pressure to contact a portion of a sheet spaced from the carrier member whereupon the differential pressures are equalized and a second differential suction pres sure is formed whereby the displaceable member is retracted by the force of the second differential suction with the sheet sucked thereagainst so that the sheet is held against the carrier member.

BACKGROUND OF THE INVENTION Field of the invention The invention relates to a transport mechanism for sheet material which employs suction to hold the sheet material against a movable member.

Prior art In machines which process sheet material such as cardboard or the like, it is known to employ a flat member above which is placed a pile of the sheets and from which, by a reciprocal motion the flat member carries the lower sheet in each working cycle, under a gauge, so as to introduce the sheet to a processing machine, the Sheet being carried by the application of suction to the sheet through suction holes having outlets in the upper surface of said member.

It has been found, however, that with a warped or bent sheet, it is possible that the sheet is not subjected to sufficient suction so as to be transported with the reciprocal member.

SUMMARY OF THE INVENTION It is an object of the invention to avoid this deficiency, and to this end it is contemplated to provide a displaceable member in the reciprocal carrier member which is supported for movement by means of a first pressure ditferential between a retracted position and a projected position in the latter of which the displaceable member engages a portion of the sheet material to apply suction force thereto, and then automatically by means of a second pressure differential to bring the sheet against the upper surface of the carrier member. Thereby the lower sheet is always transported with the carrier member even if it is warped or bent.

In order to effect automatic projection of the displaceable member until it contacts the sheet whereupon the displaceable member is then automatically retracted with the sheet sucked thereagainst, there is formed a first chamber bounded in part by the displaceable member. A suction source communicates with said first chamber through a large passageway. A throttled passageway extends from said first chamber to a second chamber and said second chamber communicates with a large outflow passageway in said displaceable member whereby a first "ice pressure differential is created between said first and second chambers. The first pressure differential operates on the displaceable member to cause the same to project from the carrier member. If the displaceable member contacts the sheet it will be sucked thereagainst and block the outflow passageway so that the pressures in the first and second chambers will be equalized. At this point a second pressure differential is created between essentially the second chamber and the atmosphere. This second pressure differential forces the displaceable member and the sheet which is attached thereto by suction, to a relatively retracted position holding the sheet against the fiat surface of the carrier. Interruption of the suction equalizes the second pressure differential and releases the sheet.

If the displaceable member does not contact the sheet, the first pressure differential remains so long as the suction is applied. Upon discontinuance of the suction the displacement member retracts of its own weight or by the supplemental action of a spring which may be provided.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a known transport mechanism;

FIG. 2 is a section through a part of the mechanism of FIG. 1 showing the mechanism operating with a warped sheet,

FIG. 3 is a plan view of a mechanism embodying my invention,

FIG. 4 is a side section view through the mechanism of FIG, 3 in a first operative position, and

FIG. 5 is a similar view of the mechanism in a second operative position.

DETAILED DESCRIPTION As seen in FIG. 1 a fiat plate member 1 is adapted to transport the lowermost sheet of material of a pile lying thereabove (not shown) under a gauge 2, one by one, to a processing machine (not shown).

The member 1 is driven in a reciprocal motion in its plane in the direction of the arrows 3, by an oscillating lever 4.

On at least a part of its upper surface and always near the gauge, member 1 has a portion with holes 5, through which a suction force is exerted on the lower sheet of the pile, the suction being intermittently produced in member 1 through a pipe 6 coupled to a vacuum pump by a control-valve.

As shown in FIG. 2, a drawback of the known arrangement is that if the sheet to be seized is not absolutely plane as represented by sheet 7, the suction cannot be exerted and the introduction of the sheet into the process ing machine will not take place.

The present invention contemplates the provision of

suction members

5, 5" supported in member 1 for displacement between two positions, one in which it is generally flush with the surface of member 1 (FIG. 5) and the other in which it protrudes therefrom, by a pres sure differential, against the lower face of the sheet to be transported (FIG. 4), the suction members being controlled so that when the sheet is contacted the suction members are retracted with the sheet sucked thereagainst whereby the sheet is placed against the upper face of the member 1. The suction is interrupted on introduction into the processing machine to release the sheet, the suction members 5', 5" remaining retracted until the return of the suction for the seizure of a new sheet.

In FIG. 3, it is seen that the suction members 5', 5" are provided in addition to the holes 5. As seen in FIG. 4 a vacuum chamber 8 is formed in member 1 to supply suction to holes 5.

The suction member 5 (FIG. 4) is slidable in a cylinder 11 which is secured by a wing-screw 9 threaded on a rod of the cylinder 11 which passes through a cylindrical housing on the member 1.

A cover 12 is fixed on cylinder 11 and slidably receives a rod portion 13 attached to a base or piston 14 of member 5'. Portion 13 is in the shape of a hollow cylinder having an opening 15 in a cover piece 15. The portion 13 communicates, at its lower part, with a second chamber 16 located under the base 14. The opening 15 opens into the interior of an annular elastic member 17 which contacts a sheet of material as will be explained later.

The cylinder 11 is provided with an outer annular recess 18, and there is formed an inner annular first chamber 19 bounded by cover 12, member 5' and cylinder 11.

The recess 18 is in communication with the first chamber 19 through one or several ducts 20 of relatively large section, whereas the first chamber 19 communicates with the second chamber 16 in the interior of member 5' through one or several holes 21, of small size and forming a narrowing or throttling in relation to the ducts 20. This throttling serves to create a pressure differential between the first and second chamber upon application of a suction to the first chamber.

A spring 22 is disposed in chamber 19, acting on the one hand against piston 14, and on the other hand against the cover 12, tending to urge the member 5 to the bottom of cylinder 11.

The spring 22 can however be omitted and the piston be urged to its lower retracted position under the sole effect of its weight, by arranging the member 5' in vertical position.

The annular recess 18 communicates with a suction pipe 23.

The mechanism operates as follows:

As shown in FIG. 4, the suction in pipe 23 creates a vacuum in the annular recess 18, and, through the ducts 20, in the chamber 19.

This vacuum is weakened by reason of the existence of the holes 21, establishing communication between chamber 19 and the outlet opening 15 to establish a sucking vent in annular member 17. However, since the holes 21 provide a throttling effect (the total section of openings 20 preferably is greater and at least equal to that of the holes 21) a first pressure difference will exist between the

chambers

16 and 19 which differential will overcome the action of the spring 22 (if used) and raise the member 5' to the position shown in FIG. 4. In the absence of the spring 22 the pressure difference will merely have to overcome the weight of member 5'.

This projection of the member 5' will enable elastic member 17 to contact the lower surface of a portion of a sheet to be transported which may be initially spaced from the upper surface of member 1. It is obvious that the member 5 will be raised only until it contacts the sheet as will be additionally explained hereinafter.

At the time the elastic member 17 contacts the sheet, the latter seals the opening 15 such that the full suction can now be produced in

chambers

16, 18 and 19 and interconnecting passageways 20 and 21.

At this point the first pressure differential in

chambers

16 and 19 is cancelled or equalized. After equalization of the first pressure differential and upon the continuous application of suction a second pressure differential is created between second chamber 16 (including the portion 13) and the atmosphere as a result of the sheet closing off Opening 15 from the atmosphere.

This second pressure differential forces the piston 14 down against the bottom of cylinder 11 to reduce the second chamber 16 and the passageway in portion 13 to a minimum size. It will be understood that the member 15 with the sheet held thereto by suction will be retracted to hold the sheet against the fiat upper surface of the carrier member.

If the sheet is not contacted the displaceable member 5' will remain in its extending position until the suction is interrupted. Upon the dissipation of the suction the member 15 is urged to the bottom of cylinder 11, under the action of its own weight and spring 22 (if used) as shown in FIG. 5. The sheet 7 is thus sucked by the member 5' and applied against the member 1, the orifices 5 of which can in turn keep it correctly flat in order to cause it to pass under the gauge.

The working cycle is as follows:

As the conveying member 1 is brought to a position under a pile of sheets, a valve means (not shown) will place the pipe 23 into communication with a vacuum source. Under the effect of the vacuum, and the consequential first pressure differential as has already been shown, the suction member 5' will rise until it contacts the sheet, after which it will automatically retract under the force of the second pressure differential with the sheet sucked thereagainst and apply the sheet onto the upper surface of member 1. A second valve means (not shown) may be provided so that it will at that moment put the third vacuum chamber 8 in communication with the same or another vacuum source to create a third pressure differential between chamber 8 and the atmosphere, bringing about a perfectly fiat applicationof the sheet on the member 1. If the vacuum forces are the same in the second and third chamber the third pressure differential will be the same as the second pressure differential.

While maintaining the vacuum in the chamber 8 and pipe 23, the member 1 will then be moved forward, transporting and introducing the sheet into the processing machine.

Upon introduction of the sheet to the processing machine, the member 1 occupies its most forward position. At this point the suction will be interrupted in chamber 8 and pipe 23 and the second and third pressure differential will disappear to free the sheet for movement by the processing machine. The sheet will then be released and, under the effect of the spring 22, and/or the weight of member 5, the member 5' will remain in retracted position in member 1 to allow unimpeded backwards movement of the member 1 under gauge 2, to its most rearward passage for engagement with the next sheet.

Once the member 1 is moved back, the aforementioned operation is again repeated until the pile is exhausted or as desired. It is to be understood that between the valve means controlling the suction and the motions of the member 1, there is a suitable linkage to insure the synchronization of the working cycle described.

One large vacuum source may serve to operate both the displaceable member 5' and provide suction to the third chamber 8. On the other hand, it may be necessary to provide for two vacuum pumps, for the reason that each should be capable of working to full output and at the required instant without one pump effecting the other or the pressures in the associated chambers.

The embodiment described shows a conveying member with two suction members 5', 5". It is obvious that there could be only one or, on the contrary, more than two of such suction members.

The suction members could be of a construction different from that described, on condition that the af0rementioned working cycle is carried out. For instance, there could be provided a fixed piston surrounded by a movable cylinder bearing the so'called sucking vent.

What is claimed is:

1. In a mechanism for transporting sheet material having a movable carrier member with a flat upper surface, the improvement comprising a displaceable member supported in the carrier member for movement between a first position in which the displaceable member is retracted with respect to the flat upper surface of the carrier member and a second position in which the displaceable member projects from said upper surface for contacting a portion of a sheet of material that may be spaced from said upper surface, a first suction chamber bounded in part by the displaceable member communieating with a suction source, a second chamber bounded in part by the displaceable member and in communication with the atmosphere by means of a large opening through said displaceable member, a small passageway between said first and second chambers providing communication of said suction from said first chamber to said second chamber and said opening, said small passageway providing a throttling effect on said suction to thereby create, when said suction is being applied, a first pressure differential between said first and second chambers that acts on the displaceable member to urge it to an extended position for contact with the sheet which sheet, when contacted, blocks the communication of said second chamber to the atmosphere thereby allowing equalization of pressure between said second and first chambers which equalization in turn forms a second pressure differential between said second chamber and said atmosphere, said second pressure differential operating on said sheet and said displaceable member to force it into its retracted position with the sheet of material sucked thereagainst.

2. An improvement according to claim 1 wherein said movable carrier member is provided with a plurality of suction holes having outlet in said upper surface which suction holes serve to hold the sheet on the carrier by means of a third pressure differential.

3. An improvement according to claim 2 wherein a single suction means provides the suction for said displaceable member and for said third pressure differential.

4. An improvement according to claim 1 wherein said movable carrier member is provided with a bore and a cylindrical member fixed in said bore and slidably receiving said displaceable member, a cover fixed on said cylindrical member and accommodating the displaceable member for passage therethrough, said first chamber being bounded by said cylindrical member, said cover and the displaceable member, a vacuum source communicating with said first chamber.

5. An improvement according to claim 4 wherein said displaceable member has a piston portion on one end and a sheet contacting means at its other end with said large opening therebetween, said piston portion forming said second chamber with said cylinder, said small passageway being through said piston portion.

6. An improvement according to claim 5 wherein an annular recess is provided between said bore and said cylinder, said annular recess opening to said first chamber and being positioned in the communication line between said first chamber and said suction source to facilitate distribution of said suction to said first chamber, said etfective opening to said first chamber being greater than said efiective opening area of said small passageway between said first and second chambers.

7. An improvement according to claim 5 wherein said sheet contacting means comprises an annular elastic member extending from said cover piece and surrounding the opening therein.

8. A sheet material transporting apparatus including a carrier member having a sheet material engaging Surface, said carrier member movable from a supply of sheet material processing machine, said carrier having at least one displaceable suction means associated therewith for grasping said sheets, said displaceable suction means operable by a single continuous suction source applied thereto to rise above the level of said carrier, attach itself to a sheet and retract under the force of said suction, said displaceable suction means including a cylinder member having a closed bottom and a top cover, said cover having an opening therethrough, a displaceable member having a lower piston portion, a central hollow cylindrical portion and an upper material contacting portion, said hollow cylindrical portion passing through said cover and said piston portion slidably received in said cylinder member, a first chamber bounded by said cylindrical member, said piston portion, said cylindrical portion and said core, said suction source being connected to said first chamber, a second chamber formed between said piston portion and said cylinder, said second chamber being in communication with the atmosphere through said central hollow cylindrical portion and through an opening in said upper material contacting portion, a small suction throttling passageway between said first chamber and said second chamber whereby a greater suction force is created in said first chamber than in said second chamber when said second chamber is in communication with the atmosphere.

9. An apparatus according to claim 8 wherein a spring is provided between said cover and said piston portion to urge said displaceable member downwardly against said cylinder member bottom, said spring being overcome by the suction force in said first chamber when said second chamber is in communication with the atmosphere.

10. An apparatus according to claim 8 wherein said displaceable means is received in a cylindrical housing member on said carrier member and held thereinby releasable connection means.

11. An apparatus according to claim 10 wherein said cylinder member has an exterior annular recess that cooperates with said housing member and said suction source to provide a suction distribution passageway about said first chamber.

References Cited UNITED STATES PATENTS 8/1961 Gulick 271-26 8/1965 Dovey 2.7132