US3907278A

US3907278A - Suction assisted endless belt separator

Info

Publication number: US3907278A
Application number: US441438A
Authority: US
Inventors: Jean-Philippe Jaton
Original assignee: J Bobst et Fils SA
Current assignee: Bobst Mex SA
Priority date: 1973-02-28
Filing date: 1974-02-11
Publication date: 1975-09-23
Anticipated expiration: 1992-09-23
Also published as: IT1006382B; FR2219663A5; DE2404323B2; ES423722A1; CA1028722A; DE2404323C3; CH565697A5; SE393790B; JPS49118170A; JPS5320748B2; GB1443077A; DE2404323A1

Abstract

A device is disclosed for feeding sheets to a sheet processing machine, such for example, as to a folding and pasting machine. The novel feeding mechanism includes at least one conveyor having at least one endless belt. The endless belts are intermittently advanced to carry one sheet at a time taken from a pile disposed above the belt or belts. The intermittent advancement of the belt or belts is brought about through a one-way clutch coupling a drive pulley to a crank arm which is oscillated back and forth through a link mechanism driven by a continuously rotating drive wheel. The machine to which the sheets are successively fed includes a pair of pressure feed rollers to which the leading edge of each sheet is moved. After the sheet is grasped by the feed rollers, further movement of the sheet continues the advancement of the belt while the belt drive roller is freewheeling. The belt has a large number of perforations and a vacuum chamber is located below the belt over a region representing a substantial forward portion of the pile of sheets.

Description

United States Patent [191 J aton Sept. 23, 1975 SUCTION ASSISTED ENDLESS BELT SEPARATOR [75] inventor: Jean-Philippe Jaton,Chapelle,

Primary ExaminerRichard A. Schacher Assistant ExaminerBruce H. Stoner, Jr.

Attorney, Agent, or Firm-Hill, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson [5 7] ABSTRACT A device is disclosed for feeding sheets to a sheet processing machine, such for example, as to a folding and pasting machine. The novel feeding mechanism includes at least one conveyor having at least one endless belt. The endless belts are intermittently advanced to carry one sheet at a time taken from a pile disposed above the belt or belts. The intermittent advancement of the belt or belts is brought about through a one-way clutch coupling a drive pulley to a crank arm which is oscillated back and forth through a link mechanism driven by a continuously rotating drive wheel. The machine to which the sheets are successively fed includes a pair of pressure feed rollers to which the leading edge of each sheet is moved. After the sheet is grasped by the feed rollers, further movement of the sheet continues the advancement of the belt while the belt drive roller is free-wheeling. The belt has a large number of perforations and a vacuum chamber is located below the belt over a region representing a substantial forward portion of the'pile of sheets.

5 Claims, 4 Drawing Figures US Patent Sept. 23,1975 Sheet 1 of2 3,907,278

US Patent Sept. 23,1975 Sheet 2 of2 3,907,278

SUCTION ASSISTED ENDLESS BELT SEPARATOR FIELD OF THE INVENTION Sheet feeding devices have been known in the past which have at least one stop against which there bears a pile of sheets placed on at least one conveyor belt and have also included means permitting the separation of the sheets one by one and their introduction into the machine in a given rhythm which can be checked. Such a device is described in Swiss Pat. No. 424,448 and Swiss Pat. No. 493,396.

It is also known in the art to use an endless belt machine such as above described which is perforated and which is displaced in a cavity in which a reduced pressure is created. Such a device is disclosed in German Patent Application No. 1,925,179.

In devices of the type above referred to, it has been noted that at the moment of departure of the sheet a slip occurs between the conveyor belt and the printed side of the sheet. This friction has been a source of soiling of the belt by the printing ink of the sheet, and it has also been noted that the departure of the sheet can not be controlled accurately. Both of the above aspects of the prior art machines referred to are a distinct disadvantage.

BRIEF SUMMARY OF THE PRESENT INVENTION The present invention provides a novel sheet feeding machine which overcomes the above disadvantages. Specifically, the present invention provides a sheet feeding device of the type having at least one endless belt, which is intermittently advanced to carry one sheet at a time from a pile disposed above the belt or belts. The intermittent advancement of the belt or belts is brought about through a one-way clutch coupling a drive pulley to a crank arm which is oscillated back and forth through a link mechanism driven by a continuously rotating drive wheel. The machine to which the sheets are successively fed includes a pair of pressure feed rollers to which the leading edge of each sheet is moved. After the sheet is grasped by the feed rollers, further movement of the sheet continues the advancement of the belt while the belt drive roller is freewheeling. The belt has a large number of perforations and a vacuum "chamber is located below the belt over a region representing a substantial forward portion of the pile of sheets.

More specifically, the present device is characterized in that it comprises a shaft for driving the drive pulley which includes a uni-directional coupling means between the drive shaft and the drive pulley. It also includes means for driving the shaft by imparting an alternating rotary movement thereto in such a manner that the belt is only driven by the drive pulley in one direction, and hence once the sheet has been grasped by the conveying means of the machine to which the sheet is to be fed, the sheet drives the belt and consequently the pulley, which free-wheels. The feeding device further includes means for braking the belt after the sheet grasped by the conveying means of the processing machine has left the belt.

Thus, once the sheet is grasped by the sheetconveying means of the machine, the endless belt no longer intervenes in an active manner but becomes passive, and any slipping between the sheet and the endless belt is eliminated. Since the endless belt, which tends to continue its displacement because of its inertia and the inertia of the pulley, is braked, untimely entrainment of the following sheet is avoided.

THE DRAWINGS The accompanying drawings illustrate, by way of example, a preferred embodiment of the present invention.

FIG. 1 is a diagrammatic side view, in section, thereof.

FIG. 2 is a diagrammatic view in section as taken along line II-II of FIG. 1.

FIG. 3 is a diagrammatic view in section as taken along line IIIIII of FIG. 1.

FIG. 4 illustrates, diagrammatically, a modified form of the present invention.

DETAILED DESCRIPTION The feeding device illustrated in the drawings comprises one or more endless belts I, placed side by side according to the width of the sheets to be introduced and having perforations 2. The sheets for which the present feeding device is particularly adapted for use are cardboard. This endless belt 1 is guided by rollers 3 and 4, a transmission pulley 5 and a tension roller 6 which is displaceable and can be locked in position in such a manner as to ensure a suitable tension of the endless belt 1. The endless belt] is further supported by three rollers 8 and by a vacuum chamber 10 fixed to a cross-bar 12. A permanent reduced pressure is created in the vacuum chamber l0v by means of a vacuum source (not illustrated) connected by a flexible pipe 13 to a pipe 14 of the vacuum chamber 10. This chamber 10 is illustrated in cross section'in FIG. 3. It is fixed to the cross-bar 12 by screws 57 and has, in its upper portion and over its whole length, an opening 59 which covers the endless belt 1, held in permanent contact with the upper portion 10a of the chamber 10, the perforations 2 being displaced opposite the opening 59.

The rollers 3, 4, 6 and 8, the transmission pulley 5 and the cross-bar 12 are fixed to a vertical plate 15, itself fixed to a transverse beam 21, connecting two supports 23 and 24 (FIG. 2) by means ofa fixing and locking device 16 comprising a pin' 17 one of the ends of which comprises an eccentric 18 to which is fixed a ball bearing 19, the other end being equipped with a knurled knob 20 serving to actuate the device 16. A locking handle 61 locks the pin 17 in its position of use. Thus, by turning the knurled'knob 20, it is possible, through the action of the eccentric 18, to position the plate 15 and the members which are fixed thereto, laterally in a very precise manner-,in relation to the supports. The transmission pulley' 5 is mounted on a drive shaft 28 extending between two vertical supports 23 and 24 (FIG. 2).

A pile of sheets of cardboard 7 is illustrated, bearing on the one hand against the endless belt 1 and on the other hand, at the front, against a'gauge 9, known per se. This gauge is adjusted in such a manner as to leave a space 11 corresponding to the thickness of one sheet between itself and the endless belt 1. At the rear, the pile of sheets of cardboard 7 rests on at least one roller 38 fixed to the end of an adjustable arm 39 held in a rectangular U-shaped bracket 40 fixed to a horizontal transverse bar 41, rigidly connected to the support on which the bracket 40 can slide and be locked in the desired position by means of a screw 43, while the arm 39 can be fixed in the desired position on the bracket 40 by means of a locking screw 42. These members are known from the earlier devices. The sheet 7a, which is being fed, is illustrated resting entirely on the endless belt.

Likewise illustrated diagrammatically, in front of the gauge 9, are two

drive rollers

33 and 34 representing the sheet-conveying means of the machine processing these sheets.

The transmission pulley is mounted on the one hand on a ball bearing (FIG. 2) and on the other hand on a one-way clutch or unidirectional coupling device 26 of the free-wheel type, of any design well known per se. Such a clutch is exemplified as comprising an inner ring 26a and an outer ring 26b, rigidly connected to one another for rotation in one direction of rotation by wedging of the tapered rollers 35. The ring 26a and the inner ring of the bearing 25 are driven onto a sleeve 27 positioned on the shaft 28 by a key 29. On the other hand, the sleeve 27 passes through the plate 15 in which it can rotate in a ball bearing 53. The sleeve 27 is held axially on the plate 15 on one side by a split resilient ring 56 and on the other by a spacing ring 55. The drive shaft 28 is positioned and held in the supports 23 and 24 by

ball bearings

44 and 45, the ball bearing 44 being held between two split rings 50 and 50', while the ball bearing 45 is held between two

split rings

52 and 52. On the other hand, the shaft 28 has a journal 46 locked laterally in the ball bearing 44 by means of a sleeve 47, a supporting washer 48 and the crank 30, the whole being secured by a split ring 49. The other journal 51 of the shaft 28 is mounted free in the ball bearing 45 so as to permit the axial expansion of the shaft.

Fixed to the journal 46 of the shaft 28 is a crank keyed onto the shaft by a key 29 (FIG. 1). This crank 30 carries a crank-pin 58 on which there is articulated the end of a connecting rod 31, the other end of which is articulated on an eccentric crank-pin 36 of a wheel 32.

The device operates as follows:

The wheel 32 is driven with a continuous rotational movement in the direction of the arrow F1, the speed of rotation being adapted to the working rhythm of the machine processing the sheets, that is to say to the speed of rotation of the

drive rollers

33 and 34. The effect of the rotation of the wheel 32 is to impart to the crank 30 a movement which oscillates between the two extreme positions 58' and 58" of the crank-pin 58. The corresponding positions of the connecting rod 31 and of the crank-pin 36 are illustrated by the broken lines 31 and 31", and 36 and 36", respectively. The are 58-58 is such that the corresponding arc A-B measured on the drive pulley 5 is slightly greater than the distance separating the front face 9a of the gauge 9 from the vertical plane passing through the axes of the

rollers

33 and 34 and through the line of contact 60 of these.

The wheel 32 drives the crank 30 in the direction of the arrow F2 when the crank-pin 36, starting from the position 36', turns in the direction of the position 36.

In this direction of rotation of the crank 30, the transmission pulley 5 is driven in rotation by means of the unidirectional coupling 26. On the other hand, the pul ley 5 is not driven when the crank 30 is turning in the opposite direction to the arrow F2, that is to say when the crank-pin 36 is turning from the position 36" to the position 36.

The moment when the endless belt 1 is not being driven, which corresponds to the rotation of the crank 30 in the opposite direction to the arrow F2, will be considered first. At this moment, the lower sheet 7a of the pile 7 is drawn against the endless belt 1 by the vacuum acting through the perforations 2 in the endless belt. When the crank 30 leaves the position 58', the endless belt is driven inthe direction of the arrow F3, and with it the sheet 7a. FIG. 1 illustrates the device and the sheet in an intermediate position, the front end of sheet 7a having arrived half way between the gauge and the

drive rollers

33 and 34 and having already left the endless belt 1.

Before the crank-pin 58 reaches the position 58", the front end of the sheet 7a is grasped by the

rollers

33 and 34 turning in the direction of the arrows F4 and F5. These rollers are driven at a linear speed substantially higher than the speed of the endless belt 1, so that the endless belt is no longer driven by the pulley 5 but by the sheet 7a, by friction without slip, the pulley 5 being driven in free rotation by the endless belt 1. This free rotation of the pulley 5 is rendered possible by the unidirectional coupling 26. The sheet 7a grasped by the

rollers

33 and 34 is illustrated in chain line at 7a.

When the sheet 7a leaves the endless belt 1, this tends to continue its movement because of its own inertia and that of the pulley 5. Nevertheless, the endless belt is rapidly braked by the action of the vacuum chamber 10 on the belt and the friction inherent in the mechanism described. The total stopping of the endless belt 1 takes place shortly before the crank-pin 36 reaches position 36'. From this moment on, the transmission pulley 5 is again kinematically rigidly connected to the crank 30 and drives the belt which carries along a fresh sheet. The position of the roller 38 is adjusted in such a manner that when the rear edge of the sheet 7a passes under the gauge 9, the following sheet drops onto the endless belt which, at that moment, is substantially stopped.

FIG. 4 illustrates, diagrammatically, a modified form of embodiment of the device showing how it is possible to mount two endless-belt devices, as illustrated in FIG. 1, one behind the other in such a manner as to ensure better operational conditions for relatively long sheets, if necessary. The members of the second device bear the same reference numerals accompanied by a prime.

From the operation described above it is clear that the transmission pulley 5 is driven at a precise moment, corresponding to the point 58, this driving being ensured by a simple and precise mechanism. The departure of the sheet is therefore ensured strictly, which enables the following members of the machine to be simplified, which, when conventional devices are used for the introduction of sheets, have to ensure, by other means, such as a chain register, the advance of the sheets at precise moments, in synchronism with the sequential working phases of the machine.

The device described comprises a perforated belt and a vacuum chamber, but the perforation and this vacuum chamber are not absolutely essential to ensure the entrainment of the sheets.

Moreover, the braking of the endless belt may be effected by other means such as a vacuum chamber, which may or may not be an auxiliary one, acting on an unperforated portion of the endless belt, or a mechanical brake acting directly on the belt or on the shaft of the transmission pulley.

I claim as my invention:

1. A device for feeding a sheet processing machine having a sheet-conveying means, said device comprising at least one endless belt conveyor positioned to feed sheets successively to said sheet-conveying means, said endless belt conveyor having an upper reach disposed generally in a horizontal plane, a drive pulley for intermittently advancing the upper reach of said belt toward said sheet conveying means, said belt being adapted to entrain, one by one, sheets taken from a pile disposed above said belt conveyor to bring the front edge of a sheet to said sheet-conveying means, means for causing a sheet to be held to said belt until withdrawn therefrom by said sheet-conveying means, a drive shaft, a unidirectional coupling means between said shaft and said drive pulley, and means for oscillating said drive shaft, said belt being only driven by said drive pulley in one direction until the front edge of a sheet has been grasped by said sheet-conveying means, said sheetconveying means causing further advance of said belt until said sheet is drawn off of said belt, and means for braking the belt thereafter until the start of advancement of the next sheet by said drive pulley being directly coupled to said drive shaft to initiate a new cycle of sheet advancement.

2. A device according to claim 1, in which said endless belt conveyor is perforated, and in which suction means is disposed on the under side of said upper reach in proximity to the delivery end'of said sheets.

3. A device according to claim 2, in which a plurality of supporting rollers are disposed below the upper reach of said endless belt conveyor remote from the delivery end thereof.

4. In a machine for processing sheets, which machine includes mating driven sheet advancing rolls which advance a sheet at a predetermined speed when the sheet is gripped by said rolls; a device for feeding sheets cyclicly to said rolls comprising an endless belt conveyor; means supporting said endless belt conveyor below a stack of sheets to be fed; a drive pulley for partially advancing a sheet toward said mating rolls at a speed less than the speed at which a sheet is advanced by said mating rolls; said endless belt conveyor being partially wrapped around said drive pulley; a drive shaft; a oneway clutch connecting said drive pulley to said drive shaft; crank means for oscillating said drive shaft back and forth; said endless belt being advanced first by said drive wheel during one direction of oscillation of said drive shaft until a sheet is grasped by said sheet advancing rolls, said belt conveyor being further advanced by the pull of said advancing sheet on said endless belt conveyor, said belt conveyor being free to further advance by the free-wheeling of said drive wheel on said drive shaft, and brake means for stopping said belt conveyor after the rear edge of said belt leaves said belt conveyor.

5. A device according to claim 4, in which said endless belt conveyor is perforated and in which a suction box is disposed immediately below a portion of the upper reach of said endless belt conveyor adjacent the sheet delivery and thereof.

Claims

1. A device for feeding a sheet processing machine having a sheet-conveying means, said device comprising at least one endless belt conveyor positioned to feed sheets successively to said sheet-conveying means, said endless belt conveyor having an upper reach disposed generally in a horizontal plane, a drive pulley for intermittently advancing the upper reach of said belt toward said sheet conveying means, said belt being adapted to entrain, one by one, sheets taken from a pile disposed above said belt conveyor to bring the front edge of a sheet to said sheetconveying means, means for causing a sheet to be held to said belt until withdrawn therefrom by said sheet-conveying means, a drive shaft, a unidirectional coupling means between said shaft and said drive pulley, and means for oscillating said drive shaft, said belt being only driven by said drive pulley in one direction until the front edge of a sheet has been grasped by said sheet-conveying means, said sheet-conveying means causing further advance of said belt until said sheet is drawn off of said belt, and means for braking the belt thereafter until the start of advancement of the next sheet by said drive pulley being directly coupled to said drive shaft to initiate a new cycle of sheet advancement.

2. A device according to claim 1, in which said endless belt conveyor is perforated, and in which suction means is disposed on the under side of said upper reach in proximity to the delivery end of said sheets.

4. In a machine for processing sheets, which machine includes mating driven sheet advancing rolls which advance a sheet at a predetermined speed when the sheet is gripped by said rolls; a device for feeding sheets cyclicly to said rolls comprising an endless belt conveyor; means supporting said endless belt conveyor below a stack of sheets to be fed; a drive pulley for partially advancing a sheet toward said mating rolls at a speed less than the speed at which a sheet is advanced by said mating rolls; said endless belt conveyor being partially wrapped around said drive pulley; a drive shaft; a one-way clutch connecting said drive pulley to said drive shaft; crank means for oscillating said drive shaft back and forth; said endless belt being advanced first by said drive wheel during one direction of oscillation of said drive shaft until a sheet is grasped by said sheet advancing rolls, said belt conveyor being further advanced by the pull of said advancing sheet on said endless belt conveyor, said belt conveyor being free to further advance by the free-wheeling of said drive wheel on said drive shaft, and brake means for stopping said belt conveyor after the rear edge of said belt leaves said belt conveyor.