US2791425A - Sheet feeding means - Google Patents

Description

May 7, 1957 R. M. FORD ETAL SHEET FEEDING MEANS 2 Sheets-Sheet 1 Filed March 2, 1954 FIGZ.

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May 7, 1957 M. FORD ETAL 2,791,425

' SHEET FEEDING MEANS Filed March 2, 1954 2 Sheets-Sheet 2 FIGS.

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United States Patent SHEET FEEDING MEANS Ronald Max Ford and Denis Percy Crane, Olton, Birmingham, England; said Crane assignor to Frank R. Ford Limited, Birmingham, England, a British company Application March 2, 1954, Serial No. 413,682

Claims priority, application Great Britain March 6, 1953 12 Claims. (Cl. 271--=-36) The present invention relates to sheet feeding mechanism for duplicating or printing machines (hereinafter referred to as duplicating machines of the kind specified) having a rotary printing couple comprising a master cylinder to which may be attached a master sheet carrying the matter to be reproduced and with which co-operates a pressure roller, a feeding tray or table being provided at the front of the machine from which copy sheets may be fed one at a time from a stack placed thereon into the nip of the master cylinder and pressure roller.

Various forms of sheet feeding mechanism have been proposed involving the use of a sheet feeding roller supported in a suitable manner to engage with the topmost sheet of the stack and driven rotatably to advance the sheet into the nip of the printing couple the drive being derived from one of the components of the printing couple.

There are however special problems attendant upon producing a satisfactory sheet feeding device not all of which are met in constructions and arrangements hitherto proposed.

One of these problems is the elimination or reduction of lost motion in the drive from the printing couple to the sheet feeding roller. Such lost motion can (and, if present frequently does) result in the forward edge of the sheet being fed into the nip of the printing couple either prematurely or late so that the matter impressed on the sheet is not located accurately in relation to the sheet edges or in relation to matter already appearing on the sheet. This problem is particularly important when the copy sheet is a pro-forma in which certain data impressed thereon from the master sheet must appear in the places designated particularly to it.

Another problem of a fairly serious nature is to overcome or reduce the tendency of the two topmost sheets sticking together so that either both are advanced to the printing couple or the lower of the two sheets is given a certain premature displacement towards the printing couple.

One object of the present invention is to provide im proved sheet feeding mechanism in which lost motion in the drive to the sheet feeding roller is obviated or reduced.

A further object of the invention is to provide drive means of new or improved construction affording gradual acceleration for the sheet feeding roller of sheet feeding mechanism which moves the copy sheets from rest, thereby substantially reducing the risk of slipping of this roller relatively to the copy sheets and reducing the risk of the two topmost sheets sticking together.

A further object of the invention is to provide drive means for the rollers of sheet feeding mechanism of the kind having a primary roller which first moves the sheets from rest and a pair of secondary rollers also adapted to moisten the sheets and disposed between the primary roller and the printing couple, such drive means including a common actuating member driven in timed relation with the master cylinder of the printing 2,791,425 Patented May '7, 1957 couple and adapted to furnish the required, and if necessary different, accelerations for the primary roller and the secondary rollers so that the former may feed only a single copy sheet the latter may control the accuracy of registration of the sheet with 'a particular axial zone on the master sheet.

Yet another object of the invention is to provide drive means for connecting an actuating element driven in timed relation with the master cylinder of the printing couple to one or more sheet feeding rollers of a sheet feeding mechanism which drive means is capable of being applied without major modification to a wide variety of different sizes and different types of duplicating machine of the kind specified.

The invention will now be described with reference to the accompanying drawings illustrating, by way of example, a preferred embodiment of same and wherein:

Figure 1 is a general view in side elevation of a duplicating machine embodying one construction of sheet feeding mechanism according to the invention.

Figure 2 is a view from the opposite side of the machine on an enlarged scale, one of the side cover plates having been removed to expose the means for driving the sheet feeding rollers of the mechanism.

Figure 3 is a further view in side elevation taken in longitudinal cross section at a position in between one end of the master cylinder and the adjacent side frame member of the machine to disclose further components of the means for driving the sheet feeding rollers.

Figure 3a is a fragmentary view on an enlarged scale showing a freewheel or one-way clutch mechanism through which the secondary sheet feeding roller is driven.

Figure 3b is a fragmentary view partly in cross-section showing the transmission means accommodated in the arm which carries the primary sheet feeding roller.

Figure 4 is a fragmentary exploded view showing the detailed assembly of one of the driving members for transmitting motion from the master cylinder cam to the respective chains for driving the sheet feeding rollers.

Referring firstly to Figure 1 of the drawings there is shown therein, by way of example, one form of duplicating machine to which the sheet feeding mechanism according to the present invention may advantageously be applied. This machine may be of the kind comprising a master cylinder indicated in broken lines at 10 such master cylinder being rotatably supported between'side frame members 11 of the machine secured together at a plurality of positions by tie rods 12, this master cylinder conveniently being driven by a manually operable crank or handle 13 the spindle of which has fixed thereto a gear 14 meshing with a further gear 15 fixed to the master cylinder. It will be understood that the master cylinder constitutes one component of a printing couple of which the other component is a pressure roller 16 (Figure 3) and that copy sheets are fed when the machine is in operation into the nip between these two components after having been suitably moistened so that part of the matter carried in the form of hectographic carbon upon a master sheet 17 secured on the master cylinder will be transferred to each copy sheet in turn.

At the front of the machine may be provided a tray or table 18 for supporting a stack 19 of copy sheets of which the uppermost copy sheet is adapted to be engaged by a primary sheet feeding roller 26 supported at the lower end on a forwardly and. downwardly extending arm 21. This primary roller 20 may be of any suitable construction, for example it may comprise a pair of axially spaced roller elements disposed one on each side of the arm 21 which is of hollow construction and serves to accommodate transmission means illustrated in Figure 3b detail for conveying rotary motion from pinion 67 having a sleeve 22 fixed on the arm supporting shaft 23 which extends between the side frame members 11 of the machine. The construction and arrangement of the roller elements, arm and transmission means-may for example be as described in our prior British patent specification No. 678,157, published on August 27, 1952.

The copysheets of the stack 19 may be forwarded to the printing couple comprising a master cylinder and pressure roller 16 along an in-feed pathdefined by guide members 24, 25 and 26 and above and below this path may be disposed a pair of secondary sheet feeding rollers 27 and 28.

The upper of these rollers 27 also performs the function of applying moisture to the copy sheets-by transference of the moistening liquid from apad 29 whilst the lower roller 28 serves to press the copy sheet upwardly against the moistening roller 27 by reason of the fact that it is'pivotally supported betwen a pair of rocker members 30 which tend to urge the roller upwardly under the influence of coiled tension springs 31.

Referring now more specifically to the drive means for the primary sheet feeding roller 20 and the secondary sheet feeding rollers 27 and 28 such drive means may comprise an actuating member driven in fixed time -relationship with the master sheet. This actuating member may conveniently be in the form of a cam 32 mounted upon one end of the master cylinder in a manner which is not herein disclosed in detail but which may be as described and claimed in the specification of our United States Patent No. 2,679,801, issued Junel, 1954.

To transmit motion from this cam to the primary and secondary roller-s, respectively, driving members are provided, one of these being indicated generally at 33 and the other at 34 (Figure 2).

The driving members may conveniently be in the form of levers pivotally supported on one of the side frame members 11 of the machine adjacent to the cam 32 for movement in a plane perpendicular or substantially so to the axis of the master cylinder.

The lever 33 for the primary roller 20 may be of bell-crank form having separate components 35 and 36 as seen particularly in Figure 4.

The component 35 which is of L-shaped form as viewed in side elevation may have an arm carrying a cam follower 37 in the form of a roller coaeting with the peripheral surface of the cam as illustrated in Figure 3 and a mounting arm 38 upon which the component 36 is secured.

The component 36 may be adjusted angularly in relation to the arm 38 to a limited extent about the pivotal axis 33 of the lever by the provision of adjusting screws 40 extending through threaded openings in opposed lugs 41 formed integrally with the arm 38 at one end thereof, the inner ends of the screws 40 abutting the edges of the adjustable component 36.

At the other end the arm 38 may be provided with a tapped hole 42 for receiving a securing screw 43 passing through an arcuate slot 44 in the component 36.

The lever 34 may be of somewhat similar construction comprising an adjustable component 45 secured to a mounting component 46 which carries a follower 47 coacting with the cam 32 at a position spaced angula-rly from the follower 37 and provided with adjustment screws 48 and a securing screw 49 for adjusting'and re taining the adjustable component 45 in the desired angular relationship with the mounting component 46 about the pivotal axis 50 of the latter.

These levers or driving members are connected to respective sprocket chains 51 and 52 which lap sprocket wheels 53 and 54 which are fast respectively with shaft 68 and with a spindle 55 upon which is fixed a gear 56 meshing with a further gear '57 driving the roller 27 forming the upper of the secondary sheet feeding rollers.

Each of the'c'hains 51 and :52 lap vtheirfrespective sprocket wheels by a segment of the order of 90 thereby engaging a plurality of "teeth of the sprocket wheels and substantially reducing the possibility of lost motion occurring at this point in the driven means between the cam and the sheet feeding rollers.

The chain 51 has tangentially extending portions 58 and 59 the former of-which is connected to yieldable loading means in the form of a coiled tension spring 60 anchored at 61 to the side frame member of the machine and the latter of "which 59 is connected to the driven member or lever 33.

The position occupied by the parts as seen in Figures 2 and 3 is that which obtains just prior to rotation of the primary roller 20 in a sheet feeding direction.

It will be observed that the cam follower 37 will be moved outwardly in a radial direction upon commencement of rotation of the cam whilst the arm 36 of the lever 33 is substantially in alignment with the portion '59 of its'associated' dhain so that such outward motion of the cam follower and consequent rocking of the lever will result initially in only a slight endwise displacement of the chain and the endwise-acceleration of the latter and theacceleration of the associated sprocket 53 will consequently be of a relatively low value.

This is intentionally so arranged in order that the resultant acceleration imparted initially to the roller 20 may be such as to substantially avoid slipping of this roller with respect to the topmost copy sheet. Further 'if' the primary roller were the only sheet feeding roller this would ensure accurate longitudinal registration of the leading edge of this sheet with the particular axially extending zone on the master sheet with which it is required to be brought into contact. Further, the sticking together of successive sheets is believed to be reduced.

This is particularly important where the copy sheet already has marked thereon matter such as lines or tabu- -lated formations in relation to which the material to be applied from the master sheet is required to occupy a precisely determined position.

The chain' 52 which is driven from the lever 34 also has tangentially extending portions 62 and 63 the former being connected to a coiled tension spring 64 anchored at 65, and the latter being connected to the lower end of the lever 34 in this case however the portion 63 and the lever are shown as being disposed approximately perpendicularly to each other so that the acceleration imparted to the chain and sprocket 54 is determined largely by the form of the-cam surface which is of such form in the illustrated embodiment as to ensure that the secondary sheet feeding rollers will accelerate at a rate such that on the reception between them of the leading margin of the copy sheet forwardedby the primary roller, there is substantially no risk of slipping in this case. The copy sheet will already be in motion and maintained in motion by engagement with the primary roller 20 and may readily be arranged to buckle somewhat by virtue of a relatively lower peripheral velocity imparted initially to the secondary rollerson reception of the sheet or by starting these only after reception of the sheets therebetween.

The transmission means provided bctwecn the sprocket 53 and the primary roller 20 and the transmission means provided 'between the sprocket 54, and the secondary roller 27 may be in the form of precision gearing comprising in the first case the toothed sector 66 and pinion 67 which is fast with the tubular spindle 22 and in the second case the gears 56 and 57. The gear 57 is fixed to the shaft 69 on which it is mounted and to this shaft is also pinned or otherwise fixed a ratchet wheel 70 with which co-operate spring loaded pawls 71 arricd on the adjacent endof the secondary roller 27 which is freely journalled on the shaft 69, so that the latter whilst driven from the sprocket54 can overrun when the copy sheet is nipped between the master cylinder and pressure roller. The primary'roller 20- isfixedon a shaft 72 to which is also pinned or fixed a sprocket 73 driven by means of a sprocket chain 74 from a further sprocket Wheel 75 which is freely mounted on the shaft 23. The sprocket wheel 75 carries a spring loaded pawl 76 which engages with a ratchet wheel 77 pinned or otherwise fixed to the shaft 23 so that whilst the roller 20 is driven from the sprocket wheel 53 it also can over-run when the copy sheet with which it is engaged is nipped between the secondary rollers 27 and 28.

A particular advantage of the drive means is that the pre-loading of the chains and their associated coiled tension springs together with the lapping of a substantial segment of the sprocket wheels by such chains reduce lost motion to a very low order. Further the construction is capable of being applied without substantial modification to a variety of types of duplicating machine, whilst the initial value of the acceleration imparted to the primary sheet feeding roller 20 can be very precisely controlled by adjusting the angular relationship between the component 36 and the portion of the chain 59.

What we claim then is:

1. In a duplicating machine of the kind specified, the provision of, sheet feeding mechanism comprising, a sheet feeding roller mounted on the machine in operative relation to an in-feed path for copy sheets, a sprocket wheel connected operatively with said roller by means substantially free from lost motion in a sheet forwarding direction, an actuating member driven in timed relation with the master cylinder, a sprocket chain lapping said sprocket wheel, yieldable loading means tensioning said chain, and, a driving member connected with said chain and connected operatively with said actuating member to impart lengthwise motion to the chain in a direction effecting rotation of the roller to forward copy sheets along said in-feed path to the printing couple.

2. In a duplicating machine of the kind specified, the provision of, sheet feeding mechanism comprising, a sheet feeding roller mounted on the machine in operative relation to an in-feed path for copy sheets, a sprocket wheel connected operatively with said roller by means substantially free from lost motion in a sheet forwarding direction, a driving device including an actuating member driven in timed relation with the master cylinder, a sprocket chain and a driving member connected at one position to said chain and movable to and fro in a direction to impart lengthwise motion to said chain, yieldable loading means connected with the chain at a position spaced therealong from the position at which the driving member is connected to the chain, said loading means serving to tension a portion of the chain intermediate said positions of connection which intermediate portion laps said sprocket and to alternately yield to and absorb the movement of the driving member.

3. In a duplicating machine of the kind specified, the provision of, sheet feeding mechanism comprising, a sheet feeding roller mounted on the machine in operative relation to an in-feed path for copy sheets, a sprocket wheel connected operatively with said roller by means substantially free from lost motion in a sheet forwarding direction, a length of sprocket chain lapping a segment of said sprocket wheel and having respective portions extending tangentially from the sprocket wheel, yieldable tensioning means connected to one of said portions, a driving device including an actuating member driven in timed relation with the master cylinder, and a driving member connected to the other of said portions so as to impart oscillatory movement to the sprocket wheel.

4. In a duplicating machine of the kind specified, the provision of, sheet feeding mechanism comprising, a sheet feeding roller mounted on the machine in operative relation to an in-feed path for copy sheets, a sprocket Wheel connected operatively with said roller by means substantially free from lost motion in a sheet forwarding direction, a length of sprocket chain lapping at least a 90 segment of the sprocket wheel and having respective portions extending tangentially from the sprocket wheel, yieldable tensioning means connected to one of said portions, a driving device including a cam on the master cylinder of the machine and a driving member movable to and fro in response to rotation of the cam and having an initial acceleration from its starting position of a relatively low'value to avoid slipping of the roller relatively to the copy sheets, said driving member being connected to the other of said portions so as to impart oscillatory movement to the sprocket wheel and periodic sheet forwarding rotation to the roller.

5. In a duplicating machine of the kind specified, the provision of, sheet feeding mechanism comprising, a primary sheet feeding roller disposed in operative relation to a copy sheet table, a pair of secondary sheet feeding rollers adapted also to operate as copy sheet moistening means and disposed on opposite sides of a copy sheet in-feed path between the primary roller and the printing couple, a common actuating cam for said rollers driven rotatably in timed relation with the master cylinder of the machine, separate primary and secondary sprocket wheels connected respectively and operatively with the primary roller and at least one of the secondary rollers through transmission means substantially free from lost motion in a sheet forwarding direction but including a one-Way clutch means permitting its associated driven roller to over-run, separate tensioned sprocket chains lapping said sprockets, these chains being connected with respective driving members deriving to and fro motion from said cam at angularly spaced positions of its circumference, such cam having a shape imparting relatively low initial acceleration to said driving members to avoid significant slipping of said rollers relatively to the copy sheets.

6. In sheet feeding mechanism for duplicating machines of the kind specified having a sheet feeding roller mounted on the machine in operative relation to an infeed path for copy sheets; means for driving said roller from an actuating member driven rotatably in timed relation with the master cylinder of the machine comprising, a sprocket wheel connected operatively with said roller by means substantially free from lost motion in a sheet forwarding direction, a length of sprocket chain lapping a segment of said sprocket wheel and having respective portions extending tangentially from the sprocket wheel, yieldable tensioning means connected to one of said portions, and a driving member connected to the other of said portions said driving member being operatively connected with said actuating member and having a to and fro motion derived therefrom such that the part of the driving member connected to the other portion of said chain moves in a path which at the commencement of each cycle of operation of the machine is transverse to the length of the chain at the point of connection, thereby imparting an initial acceleration to the sheet feeding roller of a relatively low value to avoid slipping of the roller relatively to the copy sheets.

7. In sheet feeding mechanism for duplicating machines of the kind specified having a sheet feeding roller mounted on the machine in operative relation to an infeed path for copy sheets; means for driving said roller from an actuating member driven rotatably in timed relation with the master cylinder of the machine comprising, a sprocket wheel connected operatively with said roller by means substantially free from lost motion in a sheet forwarding direction, a length of sprocket chain lapping a segment of said sprocket wheel and having respective portions extending tangentially from the sprocket wheel, yieldable tensioning means connected to one of said portions, and a driving member connected to the other of said portions said driving member being rockably mounted on the machine being operatively connected with said actuating member to be oscillated thereby, said driving member having a part connected to said chain which moves in an arcuate path which at the commencement of each cycle of operation of the machine is transverse tothe length of the chainat the point of connectionand which-subsequently has'anapproximately tangential relation'with said chain, thereby imparting an initial acceleration to the sheet feeding roller of a relatively low value to avoid slipping of the roller relatively to the copy sheets.

8. In sheet feeding mechanism for duplicating machines of the kind specified having a sheet feeding roller mounted on the machine in operative relation to an infeed path for copy sheets; means for driving said roller from an actuating memberdriven rotatably in timed relation with the master cylinder of the machine comprising, a sprocket wheel connected operatively with said roller by means substantially free' from lost motion in a sheet forwarding direction, a length of sprocket chain lapping a segment of said sprocket wheel and having respective portions extending tangentially from the sprocket wheel, yieldable tensioning means connected to one of said portions, and a driving member connected to the other of said portions saiddriving member including relatively adjustable components one of which cooperates with said actuating member and the other of which has apart connected with said other portion of the chain and which moves in apath which at the commencement of each cycle of operation of the machine is transverse to the length of the chain at the point of connection thereby imparting an initial acceleration to the sheet feeding roller of a relatively'low value to avoid slipping of the roller relatively to the copy sheets, and, means for adjusting the positional relation of'the components of the driving member relatively to each other to vary'the value of the initial acceleration of the roller.

9, In a sheet feeding mechanism for duplicating machines of the kind specified having-a primary sheet feeding roller disposed in operative relation to a copy sheet table, and a pair of secondary sheet feeding rollers adapted also to operate as copy sheet moistening means and disposed'on opposite sides of a copy sheet in-feed path between the primary roller and the printing couple; the provision of means for driving said primary and secondary rollers comprising separate primary and secondary sprocket wheels connected respectively and operatively with the primaryroller and at least one of the secondary rollers through transmission means substantially free from lost motion in a sheet forwarding direction but including a one-way clutch means permitting its associated driven roller t over-run, separate tensioned sprocket chains lapping saidsprockets and including portions extending tangentially from said sprockets respective primary and secondary driving members connected to said portions, an actuating member d'riven'rotatably in timed relation with the master cylinder and coacting with the driving members to move same to and fro the part of the primary driving member connected to the primary chain having a path of movement which at the commencement of each cycle of operation of the machine is transverse to the length of the chain at the point of connection, and the part of the secondary driving member connected to the secondary chain having a path of movement which at the commencement of each cycle of operation of the machine extends substantially lengthwise of this chain at the point of connection so that the primary roller is accelerated relatively more gradually than the secondary rollers.

10. In a sheet feeding mechanism for duplicating machines of the kind specified having a primary sheet feeding roller disposed in operative relation to a copy sheet table, and a pair of secondary sheet feeding rollers adapted also to operate as copy sheet moistening means and disposed on opposite sides of a copy sheet in-feed path between the primary roller and the printing coupleythe provision of means for driving said primary and secondary rollers comprising separate primary and secondary sprocket wheels connected respectively and operatively with the primary roller 'and'at least one of the secondary rollers through transmission means substantially free from lost motion in a sheet forwarding direction but including a one-way clutch means permitting its associated driven roller to over-run, separate tensioned sprocket chains lapping said sprockets and including portions extending tangentially from said sprockets respective primaryand secondary driving members connected to said portions, a cam driven rotatably in timed relation with the master cylinder-and having an operative cam surface coacting with each of said primary and secondary driving members to move same to and fro and of a form to furnish thereto an initial acceleration'not exceeding that atwhich slipping will take place between copy sheets and said primary and secondary rollers, the angular position of the secondary driving member about the cam axis relatively to the primary driving member being such that the peripheral velocity of the primary roller exceeds that of the secondary rollers upon reception between the latter of the leading margin of a copy sheet, so that the copy sheet is caused to buckle.

11. In a duplicating machine-of the kind specified, the provision of sheet feeding mechanism comprising, a sheet feeding roller mounted on the machine in operative relation to an in-feed path for copy sheets, a cam on the master cylinder of the machine, a driving member and a sprocket wheel connected operatively with said roller by means substantially free from lost motion, and disposed in closely adjacent positions at one end of the master cylinder so as to form a compact group, a length of sprocket chain lapping a segment of said sprocket wheel and having a short portion extending tangentially from the sprocket wheel and connected to said driving member and a further portion also extending tangentially from the sprocket wheel, yieldable tensioning means connected to said further portion, a follower element on said driving member co-acting with said cam to move said driving member to-and-fro in a plane substantially perpendicular to the axis of the master cylinder, thereby moving the chain endwise and imparting oscillatory movement to the sprocket wheel to forward copy sheets along said in-feed path to the printing couple.

12. In a duplicating machine of the kind specified, the provision of, sheet feeding mechanism comprising, a sheet feeding'roller mounted on the machine in operative relation to an in-feed path for copy sheets, a sprocket wheel connected operatively with said roller by means substantially free from lost-motion in a sheet forwarding direction, a sprocket chain lapping said sprocketwheel, said chain having a portion extending tangentially from said sprocket wheel, yieldable loading means tensioning said portion, a driving device including a cam'driven in timed relation with the master cylinder, and a driving member operatively associated with said cam to be moved to-and-fro thereby with a displacement-time characteristic determined by the cam shape, and' connected'to said tangentially extending portion of the chain, means supporting the driving member for movement along a path, as defined by that travelled by the point of connection to the chain, such that the path direction changes relatively to said tangentially extending length of the chain at respective positions occupied by said point along said pathwhereby the displacementtime characteristic of'the chain, sprocket wheel, and roller are modified relatively to those afforded by the cam.

References Cited in the file of this patent UNITED STATES PATENTS 562,124 Doolittle June 16, 1896 2,204,715 Wimmer June 18, 1940 2,622,518 Peterson Dec. 23, 1952

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