US2060800A - Sheet feeder - Google Patents

Description

Nov. 17, 1936. H. EHREG ET AL SHEET FEEDER Filed Jan. 6, 1936 3 Sheets-Sheet 1 A rromvsy Nov. 17, 1936. H. EHRIG ET AL SHEET FEEDER Filed Jan. 6, 1936 5 Sheets-Sheet 2 ,N VE N TOIQ S; 16/15 155/ 9, mm 44/7004 Arromvey H. EHRIG ET A]- S HEET FEEDER Filed Jan. 6, 1936 s Sheets-Sheet a Nov, 17, 1936.

Patented Nov. 17, 1936 UNITED STATES PATENT OFFICE SHEET FEEDER Hans Ehrig and Ulrich Keilhauer, Leipzig,

Germany Application January 6, 1936, Serial No. 57,655 In Germany December 6, 1935 8 Claims. (01. all-as) feeding sheets or blanks of paper, cardboard, metal foil, and like flexible materials, piled up on a table, to the presses concerned.

The principal object of the invention is to provide a structurally improved sheet feeder, which will be of greater and more universal serviceability in the printing and allied trades, viz. which can be put in action to advantage for a greater variety of printing jobs and other work than sheet feeders knownheretofore.

This and various other objects aimed at by our invention and the advantages obtained will be more fully understood by the reader after having critically reviewed the working characteristics of the two main classes of sheet feeders known in the trade:viz. of feeders, hereinafter briefly called dashers, by which the sheets are singly transferred to the press as seen in Fig. 1 of the accompanying drawings, viz. being dashed forward one behind the other-in spaced relation-to each other;-and sheet feeders for staggered feed, hereinafter briefly called "staggerers, by which the sheets are conveyed to the press in staggered position to each other, viz. in the form of a continuous row of sheets overlapping each other to a large extent as seen in Fig. 2.

As a matter of fact known to practitioners dasher feeders have a wider range of application than staggerers, inasmuch as a great variety of different printing jobs can be carried out therewith.

' Besides carrying out jobs, wherein the sheets under treatment are still in virgin, unprinted condition, sheets, which are to be reprinted, having gone already through the press and received imprints, can be safely transferred to the press with dasher feeders, without incurring the risk of smearing, setting off and afllicting like damages to the sheets in transit.

In addition thereto bydasher feeders sheets of paper for chromolithographic, artistic and kindred purposes can be safely fed having polished,

' calendered, chalked and glazed surfaces of a delicate, highly sensitive nature, and which must be Lil safeguarded against being rubbed, shuflled or otherwise brought into frictional contact with each other.

Dasher feeders however have the disadvantage, that their output is relatively low, since the speed, at which the sheets are ultimately dashed forward to the front lay marks of the feed .table must be kept below certain limits because of the risk of buckling and tearing the front edge of sheets on striking against said front lay marks. Notwithstanding the provision of slowing-down gears in dasher feeders for retarding the sheets 5 in transit immediately before reaching the front lay marks only a maximum number not exceeding 3-5000 sheets per hour can be safely transferred in practice by dasher feeders to the press consistent with the size, weight, pliability and 10 other physical properties of the paper, of which the sheets consist.

Since printing and other presses usually can be run faster than at the rate of 3-5000 sheets per hour the output of presses fitted with-dasher feed- 5 ers is in fact curtailed by technical imperfections of those feeders, which means, that the production costs of the printing jobs carried out therewith are higher than they should be.

In contradistinction thereto with feeders for staggered feed, referred to above, in which every first sheet in transit, viz. that, which approaches the front lay marks and is the nearest thereto needs to. be ultimately advanced only through a relatively short distance so as to reach the latter, a larger number of sheets can safely be fed, averaging 5-7000 sheets per hour, consistent with their size, weight, pliability, etc.

However feeders for staggered feed (Fig. 2)

cannot be used for the reasons indicated above 30 in those many cases, where the sheets are to be reprinted as in multicolor printing, or present relatively large areas covered with imprints in bold type, made with plenty of printing ink, or

in which the sheets have surfaces of a delicate 35 nature indicated hereinbefore, and must not come into frictional, rubbing or shuttling contact with each other in transit to the press.

The invention aimsat providing a structurally improved sheet feeder, which presents the ad- 40 vantages of both classes of feeders, described above, namely which can be converted at a moments notice from a dasher feeder into a staggerer and vice versa.

In connection therewith the invention aims at so redesigning the sheet feeder concerned, that certain drawbacks occurring with feeders of the aforedescribed classes and being known as stoppers or misfeedings are eliminatedzto the press in a reliable, trouble free manner,

and without necessitating tiresome, or time consuming readjustments, conversions, etc.

For this purpose self-adjusting, suction operated actuating means are provided for gently tilting upwardly the sheet separating primary grippers and in such manner, that no "creeping will occur at the upper-most sheets of the pile, which would impair the correct registering of the sheets at the front lay marks.

Another important feature of the re-designed feeder is the provision of suction operated secondary gripping means for stretching the separated sheets in lateral direction, while they are further advanced and delivered to the sheet conveyor proper.

Still other objects aimed at by the invention will become incidentally apparent hereinafter to practitioners in this field.

The nature and scope of this invention are briefiy outlined in the appended claims and will be more fully understood from the following specification taken together with the accompanying drawings, in which:

Figs. 1-2 are fragmentary side elevations diagrammatically showing by way of an example a sheet feeder improved according to this invention; in Fig. 1 the feeder is set for dashing i. e. transferring the sheets singly and spaced from each other to the press, while Fig. 2 shows the feeder re-set for staggered feed;

Fig. 3 diagrammatically shows the path of movements of the primary and secondary grippers, cooperatively associated according to this invention for separating the sheets from the pile,

stretching them in lateral direction and delivering same to the conveyor;

Fig. 4 is a plan appertaining to Figs. 1 and 2;

Figs. 5-8 are diagrammatic lay-outs showing different characteristic positions of the sheet separating means;

Figs. 9-10 are side elevations drawn in a larger scale and showing some important structural details of the primary grippers and the suction operated means provided for upwardly tilting same;

Fig. 1-1 is a front view of said primary grippers and their tilting means;

Fig. 12 is a front view showing two of the sheet delivering secondary grippers, and the suction actuated means for laterally stretching the sheet intransit;

Fig. 13 is a cross section through one of the sheet delivering and stretching grippers.

With the objects in view stated hereinbefore the sheet feeder re-designed according to this invention and shown by way of an example in the drawings essentially consists of (A) A device for separating the sheets from a pile, lifting and advancing them in the feeding direction;

(B) A sheet conveyor, which transfers the separated sheets to the press and is provided according to this invention with two sets of actuating means adapted to work the conveyor at the operators option alternatively at two different rates of speed.

A. Sheet separating device The sheets are separated by two sets of suction operated grippers-hereinafter called primary grippers IO-lll, and secondary grippers 20-20, 2l2l', 22--22', and by means of an air blast tube having nozzles, which are diagrammatically indicated at P, P. r

The said primary grippers l0, l, while being at rest in their initial position shown in Fig. 1 engage the sheets near their front edge and are then tilted upwardly about their rear edge 1 (Fig. 9-10) by improved tilting means, which are also suction operated, whereupon the said grippers HI, ID are moved by their actuating means in the direction of arrows c--c2 in a closed path of movements seen in dot and dash lines in Fig. 3, until they reach again their initial position; while the grippers l0, l0 pass point i the sheet in transit is disengaged therefrom and is re-engaged first by the outside grippers 2020' of the secondary set, which will immediately stretch the sheet in lateral direction, as indicated in dash lines in Fig. 12, whereupon the other grippers 2l 2l', 22-22 of the secondary set join in by also engaging the sheet and advance the latter in the direction of arrow e (Fig. 3) towards the sheet conveyor; the sheet being disengaged .at point 11 and in turn re-engaged by the rollers 34, 35 of the conveyor referred to hereinafter.

Air under reduced pressure briefly called suction air is supplied from an air pump or a storage tank to the primary grippers l0, l0 through rubber tubes L3, L4, which are guided by rollers R, R (Figs. 9-10) the admission and cutting-off of the suction air being controlled by cam actuated valves or equivalent air distributing means of known design (not shown). air is supplied to the grippers 20-20', 2l2l', 2222 of the secondary set.

The mechanism for moving the grippers of the primary set along the path indicated by a dot and dash line in Fig. 3 comprises: (1) a couple of hook shaped arms ll, (2) pitmans l2, which are linked to said arms H and are slidingly guided and supported at their forked front ends by a rotary driving shaft 10, driven from shaft 80; (3) levers l3 linked to said arms H and fulcrumed at 3a; (4) pins l2, l3 projecting from said pitmans l2 and levers l3 respectively and being cooperatively engaged by covered cams (not shown), which are formed within a rotary disk l4 keyed to the driving shaft 10.

The mechanism for moving the grippers 20-2D', 2|-2l', 22-22 of the secondary set along the path indicated by a dash line in Fig. 3 comprises: 1) two pairs of angular arms 21, (2) double cranked levers 28 linked to said arms 21 and fulcrumed at M, (3) pins 21, 28' projecting from arms 21 and levers 28 respectively and being cooperatively engaged by covered cams (not shown), which are formed within rotary disks 29, 29' (Fig.4) keyed to the driving shaft ID.

A structurally improved tilting mechanism operated by suction airis provided for the purposes of this invention for tilting the primary grippers I0, 10 around their rear edges rr' on engaging the top sheet of the pile S. Said tilting mechanism comprises: (1) air cylinders I5, l, which are in communication with the atmosphere at 5a and are connected at 50 with tubes L, L2 leading to the suction air distributing means (not shown) referred to above; (2) spring loaded pistons 5i slidably fitted in said cylinders and being responsive to suction air propagating therein as seen in Fig. 10, (3) pin and slot gears I 6 of arc shape, which are formed at the upper ends of arms II for guiding the grippers l0, l0 during their tilting motion, the center of the arcs concerned being at r-r'; (4) bell crank levers l1 and links l8, l9 interconnecting said pistons 52 and grippers l0, l0.

Likewise suction One of the outstanding advantages derivedfrom operating the above describedtilting mechanism indirectly by suction air instead of by directly and positively acting power transmitters lies therein, that the improved tilting mechanism is self-adjusting: Sheets differing in their thickness and pliability-e. g. tissue paper as against thick and stout paper-are differently, namely, individually treated during the tilting action: Since the total power transmitted from the pistons 51' and available at the grippers I0, 10 for upwardly folding the front edges of the sheets is in all cases practically the same the grippers I0, ID are tilted through a smaller angle-approximately 2030-in the case of sheets of stout paper than in the case of thinner papers being under treatment, where the tilting angle will be about 30-40.

Another advantage lies in the fact that, in all cases ample time is given to the grippers l0, I for settling upon, firmly engaging by suction and upwardly folding the sheets to be separated;-

thus avoiding misfeedings, which are often due to insuflicient time being given to the grippers for settling upon and securely engaging by suction the sheets, when the pressand its feeder run at high rates of speed; in other words a noteworthy feature consists in the grippers I0, 10' being declutchcd or emancipated during their settling, engaging and tilting action from any directly or positively acting driving elements of the feeder and being meanwhile practically independent of the working speed of the latter.

As explained above the sheets separated and lifted by the primary grippers l0, l0 are disengaged therefrom and reengaged ati (Fig. 3) first by the grippers 20-20' of the secondary set in order to be laterally stretched. The stretching mechanism with which the grippers 20-20' are structurally associated according to this invention is also suction operated and comprises: (1) air cylinders 25-45, which are in communication with the atmosphere at 511 and to which suction air is supplied at e through rubber tubes and a distributing device of known design (not shown); (2) spring loaded pistons 5n, which are responsive to suction air propagating in said cylinders, and to which the grippers 20, 20' are attached; the nozzles of the latter being in communication with the cylinders 25, 25' through channels 21',

The sheets in transit on being engaged near their lateral edges by the grippers 20-20' (Fig. 7) are simultaneously stretched as indicated in dotted lines in Fig. 12 and are thereupon engaged also by the grippers 2l--2l', 22-22 for being delivered in flattened condition to B. The sheet conveyor and out of operation at the operator's option.

The said power transmission gears comprise: (1) aniaxle 60; (2) sprocket wheels 40-50 journalled thereon and being connected by chains with corresponding sprocket wheels 42-52 attached to drum 30; (3) elliptic spur wheels "-5! journalled on axle 60 and locked with the sprocket wheels 40--50; (4) elliptic spur wheels 43-53 journalled on the rotary shaft and being slotted for cooperation with grooved and toothed clutches ll-l2, which are geared by means of key and slot gears Ia-1c with the rotary shaft 10; (5) double armed levers 13-44 engaging said couplings ll-12 and being operated by a connecting rod having a handle 18.

The ratios of gearing of said chain drives are so chosen, that, when clutch ll engages spur wheel 43 the sheets are carried forward singly and spaced from each other as with da'sher-feeders (Fig. 1) while, when clutch I2 is in operation as seen in Fig. 4 the sheets will overlap each other as in feeders for staggered feed (Fig. 2) referred to at length in the preamble of this specification.

Instead of the said elliptic spur wheels 4l--43, 5I53 other variable speed gears or equivalent slowing down mechanisms may be conveniently used for retarding the sheets on approaching the front lay marks.

Various other changes and modifications may be made in the structural details of sheet feeders of the improved design described hereinbefore without deviating from the spirit and the salient ideas of this invention.

For instance in addition to the hand operated connecting rod 15 a self-acting electromagnetically operated control mechanism may be provided for throwing out of operation the respective clutches H or 12 in case of misfeeding.

The chain drive 40-42 may be dispensed with altogether, where the press concerned is designed for staggered feed only.

Obviously the total number of the grippers provided for the primary and secondary set may be varied, namely chosen consistent with the maximum width of the sheets for which the feeder is built.

What we claim is:

1. In a sheet feeder for printing presses, ruling, folding and like machines the combination with means for separating the sheets from a pile, of means for conveying the separated sheets to the press, said separating means comprising two sets of grippers, a primary and a secondary one, which are cooperatively arranged at the front-end of the pile of sheets, the grippers of the primary set being adapted to engage the sheets from above and being provided with means for being tilted and moved in a closed cycle of movements, so as to separate, lift and advance the sheets in the feeding direction, the grippers of the secondary set being adapted to subsequently engage the sheets from underneath and being provided with means for laterally stretching the sheets and for being moved in a closed cycle of movements soas to further advance and deliver the sheets to the conveying means.

2. In a sheet feeder for printing presses, ruling, folding and like machines the combination with means for separatirfi the sheets from a pile, of. means for conveying the separated sheets to the press, said separating means comprising two sets of grippers, a primary and a secondary one, which are cooperatively arranged at the front end of the pile of sheets, the grippers of theprimary set being adapted to engage the sheets from above and being provided with means for being tilted and moved in a closed cycle of movements,

so as to separate, lift and advance the sheets in the sheets from underneath and being provided with means for laterally stretching the sheets and for being moved in a closed cycle of movements so as to further advance and deliver the sheets to the conveying means-and means provided at the front end of the pile of sheets for blowing air thereunder in the direction opposite to the feeding direction.

3. In a sheet feeder for printing presses, ruling, folding and like machines the combination with 'means for separating the sheets from a pile, of means for conveying the separated sheets to the press,.said separating means comprising two sets of grippers, a primary and a secondary one, which are cooperatively arranged at the front end of the pile of sheets, the grippers of the primary set being adapted to engage the sheets from above and being provided with means for being tilted and moved in a closed cycle of movements, so as to separate, lift and advance the sheets in the feeding direction,- the grippers of the secondary set being adapted to subsequently engage the sheets from underneath and being provided with means for laterally stretching the sheets and for being moved in a closed cycle of movements so as to further advance and deliver the sheets to the conveying means-said tilting means being suction operated and comprising cylinders, spring loaded pistons slidably fitted therein and being responsive to suction air propagating within said cylinders, arc shaped pin and slot gears for guiding the grippers of the primary set during their tilting motion and means for cooperatively interconnecting said grippers and pistons.

4. In a sheet feeder for printing presses, ruling, folding and like machines the combination with means for separating the sheets from a pile, of means for conveying the separated sheets to the press, said separating means comprising two sets of grippers, a primary and a secondary one, which are cooperatively arranged at the front end of the pile of sheets, the grippers of the primary set being adapted to engage the sheets from above and being provided with means for being tilted and moved in a closed cycle of movements, so as to separate, lift and advance the sheets in the feeding direction, the grippers of the secondary set being adapted to subsequently engage the sheets from underneath and being provided with means for laterally stretching the sheets and for being moved in a closed cycle of movements so as to further advance and deliver the sheets to the conveying means-said tilting means being suction operated and comprising cylinders, spring loaded pistons slidably fitted therein and being responsive to suction air propagating within said cylinders, are shaped pin and slot gears for guiding the g ppers of the primary set during their tilting motion and means for cooperatively interconnecting said grippers and pistons,-the center of thearc of said are shaped pin and slot gear being located at the rear edges of the grippers of the primary set.

5. In a sheet feeder for printing presses, ruling, folding and like machines the combination with means for separating the sheets from a .pile, of means for conveying the separated sheets to the press, said separating means comprising two sets of grippers, a primary and a secondary one, which are cooperatively arranged at the front end of the pile of sheets, the rippers of the primary set being adapted to engage the sheets from above and being provided with means for being tilted and moved in a closed cycle of movements,

so as to separate, lift and advance the sheets in the feeding direction, the grippers of the secondary set being adapted to subsequently engage the sheets from underneath and being provided with means for laterally stretching the sheets and for being moved in a closed cycle of movements so as to further advance and deliver the sheets to the conveying means,said means for stretching the sheets being suction operated and comprising two cylinders, spring loaded pistons, which are slidably fitted therein so as to be responsive to suction air propagating within said cylinders, and to which two of the grippers of the secondary set are attached viz. those which are nearest to the lateral edges of the sheets.

6. In a sheet feeder for printing presses, ruling, folding and like machines the combination with means for separating the sheets from a pile, of means for conveying the separated sheets to the press, said separating means comprising two sets of grippers, a primary and a secondary one, which are cooperatively arranged at the front end of the pile of sheets, the grippers of the primary set being adapted to engage the sheets from above and being provided with means for being tilted and moved in a closed cycle of movements, so as to separate, lift and advance the sheets in the feeding direction,'the grippers of the secondary set being adapted to subsequently engage the sheets from underneath and being provided with means for laterally stretching the sheets and for being moved in a closed cycle of movements so as to further advance and deliver the sheets to the conveying means-said conveying 'means being double geared, viz. provided with two power transmission gears difiering from each other in their ratio of gearing, and with coupling means for reciprocally throwing those gears into and out of operation, their respective ratio of gearing being so chosen, that the separated sheets are conveyed to the press either singly and spaced from each other, or collectively in the form of a row of sheets overlapping each other.

7. In a sheet feeder for printing presses, ruling, folding and like machines the combination with means for separating the sheets from a pile, of means for conveying the separated sheets to the press, said separating means comprising two sets of grippers, a primary and a secondary one, which are cooperatively arranged at the front end of the pile of sheets, the grippers of the primary set being adapted to engage the sheets from above and being provided with means for being tilted and moved in a closed cycle of movements, so as to separate, lift and advance the sheets in the feeding direction, the grippers of the secondary set being adapted to subsequently engage the sheets from underneath and being provided with means for laterally stretching the sheets and for being moved in a closed cycle of movements so as to further advance and deliver the sheets to the conveying means,-'-said conveying means being double geared viz. provided with two power transmission gears differing from each other in their ratio of gearing, and with coupling means for reciprocally throwing those gears into and out of operation, their respective ratio of gearing being so chosen, that the separated sheets are con veyed to the press either singly and spaced from each other, or collectively in the form of a row of sheets overlapping each other,said coupling means comprising a main driving shaft and two releasable clutches cooperatively associated with said shaft and the said power transmission gears.

8. In a sheet feeder for printing presses, ruling, folding and like machines the combination with means for separating the sheets from a pile, of means for conveying the separated sheets to the press-said conveying means being double geared viz. provided with two power transmission gears differing from each other in their ratio of gearing, and with coupling means for reciprocally throwing those gears into and out of operation, their respective ratio of gearing being so chosen, that the separated sheets are conveyed to the press either singly and spaced from each other, or collectively in the form of a row of sheets over-- lapping each other. I g

' HANS EHRIG.

ULRICH KEJLHAUER.

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