US2091283A

US2091283A - Platen printing press

Info

Publication number: US2091283A
Application number: US749933A
Authority: US
Inventors: Lawrence R Johnson
Original assignee: Chandler and Price Co
Current assignee: Chandler and Price Co
Priority date: 1934-10-25
Filing date: 1934-10-25
Publication date: 1937-08-31
Anticipated expiration: 1954-08-31

Description

Aug. 31, 1937. R. JOHNSON 2,091,283

PLATEN PRINTING PRES S Filed Oct. 25, 1934 3 Sheets-Sheet l INVENTOR. Lat/raf/ae 7?. MEX n60 ATTORNEX 5;

Aug. 31, 1937. L. R. JOHNSON PLATEN PRINTING PRESS Filed Oct. 25, 1934 3 Sheets-Sheet 2 ATTORNEY;

Patented Aug. 31, 1937 1 UNITED STATES PATENT OFFICE PLATEN PRINTING PRESS Application October 25, 1934, Serial No. 749,933

7 Claims.

This invention relates, as indicated, to printing presses of the Gordon or platen type, but has reference more particularly to presses of this type which are provided with pneumatic suction de- Vices for feeding sheets to and delivering them from the platen of the press.

Suction devices of the aforesaid character usually include oscillatable tubular arms provided with sucker tip assemblies adapted to engage or contact the sheets and valves for periodically breaking the vacuum in the arms and sucker tips when suction is not desired.

Occasionally, a sheet which is to be removed from the platen by the delivery sucker tips is torn or otherwise mutilated so that it will not be engaged by one or more of the sucker tips. This leaves the delivery suction line open to the atmosphere so that the sheet in question will probably fall back onto the platen. In order to prevent injury to the type form and other parts of the press, it is customary in such cases to manually stop the press and remove the defective sheet or sheets before re-starting the press. lhe starting and stopping of a press not only results in a loss of time, but causes a strain on various parts of the press, besides the loss of electrical energy in starting, which, in the case of a large heavy press, is an item of considerable expense.

The present invention has as its primary object the elimination of the foregoing diificulties and disadvantages by the provision of means responsive to the failure of the vacuum in the sheet removing means for breaking the vacuum-in the sheet-feeding means, so that the feeding of the sheets will be discontinued, but the press will continue in operation. Another object of the invention is to provide means responsive to the breaking of the vacuum in the sheet-feeding means for throwing into operation the throw-off lever oi the press.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims; the annexed drawings and the following description setting forth in detail certain mechanism embodying the invention, such disclosed means constituting, however, but two of various mechanical forms in which the principle or" the invention may be used.

said annexed drawings:

Fig. 1 is a fragmentary side elevation of a Gordon or platen type printing press embodying the invention;

Fig. 2 is a front elevation of the mechanism for breaking the vacuum in the feed line;

Fig. 3 is a side elevation of the mechanism shown in Fig. 2;

Fig. 4 is a horizontal cross-sectional view, taken on the line 4-4 of Fig. 2 and showing the normal position of the plunger which breaks the vacuum in the feed-line;

5 is a horizontal cross-sectional View, simi lar to 4, but showing the plunger in position to break the vacuum in the feed line;

Fig. 6 is a more or less diagrammatic view showing the arrangement of the various suction lines;

Figs. '7 and 8 are views similar to Figs. 2 and 3 respectively, but showing a modified form of the invention. v

A printing press of the Gordon or platen type includes, as indicated in Fig. 1, a frame i, in which is journalled the main shaft 2 having mounted on one end the large gear cam wheel 35 which is adapted to oscillate the platen (not shown) between sheet-receiving and printing positions.

The press also includes sheet-feeding and delivery mechanism, the suction line to the feeding mechanism being indicated by the numeral t in Fig. 6, such suction line being connected to one side of a double-acting vacuum pump 5, whereby the necessary suction is provided in said line.

The sheet feeding mechanism is disclosed in Root Patent No. 1,969,946, granted Aug. 14, 1934.

The sheet delivery mechanism is disclosed in some detail in Fig. 1, and includes a sucker tip assembly it which is connected to a hollow arm 'l, in which suction is maintained by means of the pump 5, through the intermediary of a suction line 8 connected to the other side of the pump and an oif-take conduit is branching from line 8.

The arm I is adapted to be moved in such a path as to cause the sucker tips to engage a printed sheet on the platen, recede from the platen, deposit the sheet on a delivery table and return to the platen for the next sheet. The necessary movement, a combined oscillatory and reciprocatory movement, is imparted to the arm "I by means of cams 9 and it, which are mounted on a shaft H, this shaft being rotated by and in synchronism with the wheel 3. During the recession of the sucker tips, the lower end of the arm l moves downwardly to the position indicated by the dotted lines in Fig. 1. For the purpose of the present invention, this downward movement of the arm 1 is the principal feature in connection with the delivery mechanism, which it is essential to bear in mind.

It will be understood that suction is to be maintained in the feeder sucker tips only during the feeding of the sheet from the feed table to the platen and in the delivery sucker tips only during the delivery of the printed sheet from the platen to the delivery table. At all other times the partial vacuum, in lines 4 and B is broken by opening these lines to the atmosphere. This is accomplished in the following manner.

The conduit 4 communicates with the atmosphere through conduits I2 and I3, and conduit 8 communicates with the atmosphere through conduits I l and i5. When suction is desired in the sucker tips, the conduits i3 and i5 are respectively closed to the atmosphere by means of tappet valves l6 and l l, which are spring-pressed to the conduit-closing position by means of a tension spring 58, which is secured at one end to a lever i9 upon which the tappets are mounted and at the other end to a lever 2d. Lever 29 is secured to a trip lever 2!, the function of which will be presently described.

The lever I9 is rigidly secured to one end of. a pin 22, which is journalled in a bracket 23 mounted on an extension of the press frame E.

Secured to the opposite end of th pin 22 is a lever 2d provided at one end with a roller 25. This roller engages a cam on the wheel 3. It will be apparent from Fig. 1 that rotation of the cam 26 will periodically lift the tappets ofi the conduits i3 and i5, so as to open these conduits to the atmosphere and break the vacuum in the feed and delivery sucker tips.

Occasionally, a sheet which is to be removes from the platen by the sucker tips is torn or otherwise mutilated so that it will not be engaged by one or more of the sucker tips. leaves the delivery suction line open to the atmosphere, so that the sheet in question will probably fall back on the platen. In order to prevent injury to the type form and other parts of the press, it is customary in such cases to manually stop the press and remove the defective sheet or sheets before re-starting the press. The starting and stopping of a press not only results in a loss of time, but causes a strain on various parts of the press, besides the loss of electrical energy in starting, which, in the case of a large, heavy press, is an item of considerable expense.

In order to avoid these difficulties and disadvantages, I have provided mechanism whereby, when a failure of vacuum in the delivery line takes place, as in the manner above described, the vacuum in the feed line will be also automatically broken.

For this purpose, there is secured to the conduits i3 and a housing 2?, the conduits ex-- tending through the housing as clearly shown in Fig. 4. The conduits i3 and i5 are respectively provided with openings 28 and 29, which are in registration with passages and 31 in the housing. The passages SE? and 3! are in communication with a cylindrical bore 32, the axis of which is transverse to those of the passages 38 and 3!. A port 33 in the housing which is dis posed opposite the passage is in communication with the atmosphere.

Slidably mounted within the bore 32 is a plunger or valve 34 having a socket in one end adapted to receive a coil spring 35, this spring abutting the housing and the plunger. This plunger is provided with two portions 3? and 38 of a diameter substantially equal to that of the bore 32 and with portions 39 and of reduced diameter, the junction of portions 3? and I 39 forming a shoulder fi-l, and the junction of portions 38 and M1 forming a shoulder The plunger is provided at its outer end with a knurled portion 43 whereby the plunger may be pushed into the housing.

The housing 2? is provided with a rearwardly extending arm or bracket to which is pivotally secured the lever or latch 2i and a second gravity-operated latch G5 is also provided, which is pivotally secured to the housing, as by means of a pivot screw 46.

When the sucker tips of the delivery mechanism are functioning in a normal manner, the vacuum in the conduit 15 is sufiiciently great to maintain the plunger 34 in the position shown in Fig. 4, in which position the spring 36 is compressed and the portion 38 of the plunger seals the passage 30 and port 33, thereby maintaining the vacuum in the feed conduit. When the tappet ii is lifted so as to open the conduit l5 to the atmosphere, the plunger 34, which would under these conditions be pushed out of the bore 32 by the spring 36 to the position shown in Fig. 5, is prevented from being so moved, by virtue of the latch 25 which engages the shoulder M of the plunger at these intervals. It will be understood that the latch 2! is periodically moved downwardly to the plunger-releasing position whenever the lever 25 is pulled downwardly by the engagement of the arm 'I with the lower hooked end of the lever, but the vacuum in conduit i5 is sufficient at such periods to hold the plunger in the position shown in Fig. 4.

Should a torn or mutilated sheet be placed on the platen and one of the sucker tips fail to make proper contact with such sheet, the vacuum in the conduit l5 will be broken, and will no longer be effective to maintain the plunger in position to seal the feed conduit i3 from the atmosphere. Consequently, when the lever 20 is pulled downwardly by the lower end of arm 7 during the receding movement of the sucker tips from the platen, the latch 2i will be pulled downwardly and the spring 36 will force the plunger 3d to the position shown in Fig. 5, the plunger being stopped and maintained in this position by the engagement of the gravity latch with the shoulder 42 of the plunger. When in this position, the feed conduit i3 is open to the atmosphere and the vacuum therein is broken. Feeding of the sheets to the platen will therefore be discontinued.

Although the feeding and delivery of the sheets are thus discontinued, the press will continue in operation. As a further precaution and to avoid possible injury to the platen or form of the press while it thus continues in operation, means have also been provided to automatically move the throw-oil" lever of the press into operation when the vacuum in the feed line 4 is broken. Such means is diagrammatically shown in Fig. 6, and includes a suction conduit 56, which communicates with the conduit 1. The throw-01f lever is pivotally mounted on a stub shaft 52 which extends from the frame of the press and has a longitudinal passageway 53 which communicates with the conduit 53. A short radially extending passageway St in the shaft 42 communicates with the passageway 53 and with a passage 55 in the throw-oil lever. The passage 55 extends to a cylindrical bore 56 of larger diameter than passage 55, and slidably mounted in this bore is a plunger 57. A coil spring 58 within the bore abuts the upper end of this plunger.

A bell-crank lever 58, which is pivotally mounted on the throw-oi? lever, has one of its arms pivoted to the lower end of the plunger 5? and has secured to its other arm a pin 59, which passes through an aperture in the lower end of the throw-off lever.

In the normal operation of the press, the suc tion in the conduit so is sufficient to overcome the action of the spring 58 and maintain the plunger 51 and pin 59 in the position shown in Fig. 6. When, however, the vacuum in conduit 50 is broken, as in the manner above described,

Cal

the plunger 51 will drop and cause the pin to enter a slot 60 in a bar 6!. Bar 6| is pivotally secured to the bed of the press and is recipro cated as the bed oscillates. The bar, in its reciprocating movement, slides on the connecting link 62 which is pivotally connected to the lower end of the throw-off lever and to the throw-off mechanism. Consequently, when the pin enters the slot 60, the throw-01f lever will be oscillated, that is, thrown into operation. It will be understood that by throwing the throw-off lever into operation is meant that the back-shaft of the bed is alternately oscillated by the throw-01f lever in such a manner that the bed will not contact the platen on the printing stroke of the bed.

As previously stated, the press, after breakage of the vacuum in the feed line, will continue in operation, and the operator, in order to resume the printing operations, needs only to remove the defective sheet or sheets, and push the plunger 34 back to the position shown in Fig. 4, whereupon the feeding and delivery of the sheets will be resumed. Resumption of suction in conduit 4 will likewise result in resumption of the suction in conduit 50, so that the pin 59 will be drawn out of the slot 60 and the throw-off lever may then be moved to its impression or printing position.

In that form of the invention shown in Figs. 7 and 8, the lifting of the tappet I6 is utilized to open the feed conduit l3 to the atmosphere in case of failure of the delivery mechanism to remove the sheet from the platen. In order to thus lift the tappet It, the following mechanism is provided. The delivery conduit has secured thereto a housing 10 in which is provided a passageway H which communicates with the interior of conduit l5 and with a vertically extending passage, in which is mounted a plunger 12. The lower end of the plunger is in abutment with a spring 13, and its upper end is pivotally connected with a trip lever 14 which is p-ivotally mounted on the housing 10. The lever 14 has a heel portion 15 under which a trip arm 16, mounted on a lever fl, is adapted to be positioned. The lever '51 is pivoted as at 18 to the housing 10 and is also pivotally connected to the lever 20, a tension spring 19 interconnecting the lever IS with the point of pivotal connection of link H and lever 20.

Downward movement of the lever 20 in the normal operation of the press has the effect of periodically withdrawing the trip arm 16 from its position under the heel l5 of the trip lever, but the suction in conduit ill at such times is suflicient to overcome the action of spring 13, so that the trip lever M remains in the position shown in Fig. 8, and the movement of the tappets l6 and H is not interfered with. In case of breakage of the vacuum in conduit l5, as previously described, the plunger 12 will be urged upwardly by the spring T3, with the result that the trip lever is caused to underlie an abutment 80 on the lever I9, thus holding both tappets l6 and Il in raised position. This will, of course, take place when the trip arm 15 is out of the position in which it underlies the heel 15 of the lever 14.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the mechanism herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In a printing press of the Gordon type, pneumatic suction means for feeding sheets to the platen of said press, pneumatic suction means for removing said sheets from the platen of said press, and means responsive to failure of the vacuum in the sheet-removing means for automatically breaking the vacuum in the sheet-feeding means.

2. In a printing press of the Gordon type, pneumatic suction means for feeding sheets to the platen of said press, pneumatic suction means for removing said sheets from said platen, and means responsive to failure of the vacuum in the sheetremoving means during movement of such means away from the platen for automatically breaking the vacuum in the sheet-feeding means.

3. In a printing press of the Gordon type, pneumatic suction means for feeding sheets to the platen of said press, pneumatic suction means for removing printed sheets from said platen, a vacuum being maintained in said last-named means only during the process of removal of said sheets from said platen, and means responsive to a failure of the vacuum in one of said means for automatically breaking the vacuum in the other of said means.

4. In a printing press of the Gordon type, pneumatic suction means for feeding sheets to the platen of said press, pneumatic suction means for removing said sheets from said platen, a vacuum being maintained in said last-named means only during the process of removal of said sheets from said platen, and means responsive to a failure of the vacuum in said last-named means for automatically breaking the vacuum in the sheet-feeding means.

5. In a printing press of the Gordon type, pneumatic suction means for feeding sheets to the platen of said press, pneumatic suction means. for removing said sheets from said platen, conduits leading from each of said means and normally open to the atmosphere, tappets for closing said conduits at predetermined intervals, and means responsive to failure of the vacuum in that conduit leading from the sheet-removing means for automatically opening the other conduit to the atmosphere.

6. In a printing press of the Gordon type, pneumatic suction means for feeding sheets to the platen of said press, pneumatic suction means for removing said sheets from said platen, conduits leading from each of said means and normally open to the atmosphere, tappets for closing the respective conduits at intervals when suction is desired in said feeding and removing means, and valve means responsive to the failure of the vacuum at such intervals in that conduit leading from the sheet-removing means for automatically opening the other conduit to the atmosphere irrespective of whether the tappet for said other conduit is in open or closed position.

'7. In a printing press of the Gordon, type, pneumatic suction means for feeding sheets to the platen of said press, pneumatic suction means for removing said sheets from said platen, conduits leading from each of said means to the atmosphere, tappets for closing said conduits at predetermined intervals, and means responsive to failure of the vacuum in that conduit leading from the sheet-removing means for maintaining both tappets in open position.

LAWRENCE R. JOHNSON.