US2410935A

US2410935A - Printing machine

Info

Publication number: US2410935A
Application number: US416548A
Authority: US
Inventors: Walter T Gollwitzer
Original assignee: Multigraphics Inc
Current assignee: AB Dick Co
Priority date: 1941-10-25
Filing date: 1941-10-25
Publication date: 1946-11-12
Anticipated expiration: 1963-11-12

Description

Nov. 12, 1946 w. 1-. GOLLWITZER 2,410,935,

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W. T. GOLLWITZER PRINTING MACHINE Filed Oct. 25, 1941 14 Sheets-Sheet 6 fil/vezv/ior Mailer 7." (j OZZWZZer @florngs Nov, 12, 1946. w. T. GOLLWITZER 2,410,935

I PRINTING MACHINE Filed Oct. 25, 194 1 14 Sheets-Sheet 7 Nov. 121946. w. T. GOLLWITZER I 2,410,935

PRINTING umcnnis Filed Oct. 25, 1941 14 Sheets-Sheet 8 Nov. 12, 1946. w, 1'. GOLLWITZER PRINTING MACHINE Filed 001:. 25, 1941 Zl/a/ZZer- T G'aZZwZzer 14 Sheets-Sheet 10 Nov. 12, 1946. v

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PRINTING MACHINE Fil ed 0ct.- 25, 1941 14 Sheets-Sheet 14 'Z/alfer Zfiollzaifzer:

' flornew Patented Nov. 12, 1946' PRINTING MACHINE Walter 'r. Gollwitzer, Euclid, ohm, assignor to Addressograph-Multigraph Corporation, Cleveland, Ohio, a corporation of Delaware Application October 25, 1941', Serial No. 418,548

22 Claims.

This application is a continuation in part of my copending application Serial No. 221,841, filed July 28, 1938. c

This invention relates generally to printing and like machines through which printing, printing and control or like devices are sequentially fed to have printing operations performed therefrom, and more particularly this invention relates to the platen mechanism of such machines whereby the desired printing impressions are made from the printing means of such devices.

In the use of printing machines of this character the printing impressions which are to be made usually pertain to identification data such as names, addresses and like information, and the printing impressions are made upon webs, sheets, businessinstruments and the like directly from the printing means of such printing, printing and control or like devices which are passed through J the machine. The printing devices from which the rinting impressions are made may take many diiierent forms, but in most instances each printing device embodies a plurality of lines of printing characters, such as embossed type, from which printing impressions may be made upon a sheet, business form or the, like. While a wide variety of printing devices may be employed in machines of the general character to time when'they are brought into printing cooperation with a sheet or business form.

In a printing device of the various types hereinabove referred to, the body of the printing device may embody control means representing variable control datarelated to the identification data represented by the printing characters carried on each such device, and this control data may be utilized for various control purposes in producing the complete business instrument pertaining to each such device. 7

When the printing devices of the aforesaid character are passed through a printing machine or the like, the printing impressions are made directly from the type characters carried by the printing devices. .These printing impressions usually pertain to identifications such as names, addresses and the like, and it will be evident that the number of type characters necessary to provide each such identification may vary substantially so that ,the printing impression made from one printing device may involve but a few type characters while the printing impressions made from another printing device may involve a large number of type characters. Such which this invention pertains, the printing device disclosed in Mohler Patent No. 1,812,894, patented July 7, 1931, is typical of one form of printing device which may be employed. Another generally similar form of printing device adapted for use in connection with the platen mechanism of the present invention is disclosed in my Patent No. 2,132,412, patented October 11, 1938. A printing device of this character includes a rectangular carrier or frame having an embossable metal printing plate removably retained in position thereon, type characters being embossed-on such a plate to appear in relief on the-operative face thereof. Printing devices of a one-piece character may also be employed, such a printing deprinting impressions are usually made through the use of a platen means which presses a-sheet into printing cooperation with the type characters embodied in the printing devices and in prior practice it has been found that the operation of such platen means has caused a heavier printing impression to be made when but a few type characters are present on a printing device than was made when a large number of type characters are present on the printing device. An important object of this invention is, therefore, to make uniform printing impressions from the printing means of such printing devices even though there may be a substantial variation in the number of type characters embodied in the printing devices which are successively passed through the printing machine. a

A further object of the invention is to enable the platen means of such a printing machine to be actuated by hydraulic means, and more pan duce an excess of such make-up liquid into the system; and to enable such excess liquid to be the movement of the platen or other impression making member of such a printing machine toward the type characters so as to stop the platen in a definite and ascertained position in each operation thereof to thereby insure that uniform impressions will be produced. A further object is to arrange the support for the printing devices and the support for the platen in a common structure so that the pressure incident to the operation of the platen will be so distributed throughout the structure that the strains incident to the printing operation cannot produce uneven printing impressions. Further objects related to the foregoing are to relieve the hydraulic pressure in the absence of a sheet below the platen to thereby prevent the formation of offsets on platen or other impression making member, and to provide a novel and efficient platen structure for use in printing and like machines. Y

Other objects and advantages of this invention will become apparent from the following claims, taken in connection with the following description and the accompanying drawings which disclose certain preferred embodiments of the invention.

In the drawings:

Fig. 1 is a front elevatlonal view of a machine adaptedfor producing business instruments and embodying platen mechanism which includes the features of the invention;

Fig. 2 is a plan view of the machine shown in Fig. i

Fig. 3 is a. front face view of a printing and control de {108 adapted for use with the machine shown in Fig. 1;

Figs. 3A and 3B are fragmentary elevational views of control cards that may be used with the printing and controldevices shown in Fig. 3;

Fig. 4 is a chart of the code under which perforations are made in the control areas of the printing and control devices such as that shown in Fi 3;

Fig. 5 is an elevational view of a. typical business instrument produced by the machine shown in Figs. 1 and 2 of the drawings;

Fig. 6 is a fragmentary elevational view of a Figs. 17 to 17A are vertical sectional views adapted to be read together as a single view and showing an alternative form of platen mechanism and hydraulic actuating means therefor;

Fig. 18 is a fragmental planview of one of the platen mechanisms of Fig. 17, the view being taken'substantially from the line I8-I8 of Fig. 17;

Fig. 19 is a vertical sectional view of the platen 10. mechanism of Fig. 18, the view being taken substantially along the line l9--I9 of Fig. 18;

Fig. 20 is a view of the main pumps of the hydraulic platen actuating means, the view being .taken substantially along the line 2020 of Fig. 21;

Fig. 21 is a longitudinal sectional view of one of the main pumps of the hydraulic system, the view being taken along the line 2i-2l of Fig.

Fig. 22 is a cross sectional view of the pump 20 actuating means, the view being taken substantially along the line 22-22 of Fig. 21;

Fig. 23 is a vertical sectional view of one of the make-up pumps of the hydraulic system;

Fig. 24 is a plan section taken substantially 25 along the line 2424 of Fig. 23;

Fig. 25 is a fragmental plan view of one of the platen mechanisms, as viewed from the line 25-25 in Fig. 17;

Fig. 26 is a fragmental vertical sectional view 80 taken along the line 2626 in Fig. 25; and

Fig. 27 is a fragmental vertical sectional view taken substantially along the line 21-21 in Fig. 26.

While I have shown in the drawings and will herein describe in detail certain preferred emconstructions falling within the spirit and scope of the invention as expressed in the appended claims.

The platen mechanism of the present invention is illustrated herein in different embodiments 46 which have a wide variety of different uses, and

for purposes of disclosure these different forms of the invention have been herein shown as embodied in machines for producing complete business instruments, records and the like. Thus the P f eet Such a y e D Q in e a- 50 first-form of the platen mechanism of the present chine shown in Figs. 1 and 2;

Fig. '7 is a fragmental vertical sectional view taken substantially along the line 1--1 of Fig. 2

and-illustrating the platen and its hydraulic acthe line l2|2 of Fi 7;

Fig. 13 is a sectional view taken along the line 13-43 of Fig. 12;

invention is. illustrated as embodied in the machine which is fully illustrated and described in my copending application, Serial No. 221,841, filed July 28, 1938, now issued as Patent No. 2,296,277,

patented September 22, 1942. Reference may, of

course, be had to my said copending application for details of structure and operation, and the present disclosure is accordingly confined to those elements of the machine which are most 60 directly related to the present platen mechanism.

55 dend check includes constantly reoccurring data F, Fig. 5, which in the present instance is the name and location of the company issuing the check, the words "Check No.." the name of the bank on which the check is drawn, and kindred Figs. 14 and 15 are diagrammatic views illusdata imparting characteristics to the check, i

trating the platen mechanismin two different positions;

Fig. 16 is a schematic wiring diagram illustrating the electrical connections whereby the platen mechanism is controlled;

cluding the border appearing thereon; changing data A, constituting an identification and characterizing the check and; in the present instance. this is an address comprising a name, street and 7 number, and city and state; variable data V -.which are the amount for which the check is to be payable; and other analogous data such as a date E, a numberN and a signature B. The date, number and signature are the first data, in the machine as constructed. to be printed; next the variable data V are printed and thereafter the address A; and finally the form F are printed on the check.

The address or changing data A are printed on the check directly from a printing and control device such as the device D, Fig. 3, and the variable data Vare printed under control of such a printing or like device. It is preferred to employ such printing and control devices for so to do eliminates the necessity of checking printing 'devices or the like against record cards or the like because the printing and control devices, such as are shown in Fig. 3, include both means from which an impression may be made directly and means under control of which impression or other operations may be performed. It is to be understood, however, that when reference is made hereinafter to a printing and control device, save in those'instances where the avoidance of checking is essential, this term is to be considered generic for, as will be apparent to those skilled in the art, the platen mechanism of the present invention may be used with printing devices not equipped with control means. Hence in view of this it is to be understood that While the devices will be described as printing and control devices, this term is used in the generic sense hereinafter, particularly in those instances where it is not essential that the control means of such-a printing and control device be employed.

The printing devices from which the printing impressions are made in such machines may take many different forms. but in most instances each printing device carries a plurality of lines of printing characters, such as embossed type, from which printing impressions may be made upon a sheet, business form or the like. variety of printing devices may be employed in machines of this character, the printing device,

disclosed in Mohler Patent No. 1.312894 patented July 7, 1931, is typical of one form of printing device which may be employed. Another general y similar form of printing device adapted for use with the present invention is disclosed in Gollwitzer Patent No, 2,132.412 patented October 11, 1938. A printing device of this character includes a rectangular carrier or frame having an embossable metal printing plate removably retained in position thereon, type characters being I embossed on such a plate to appear in relief on the operative face thereof. Type characters have also been embossed on a so-called one-piece printing device of the kind disclosed, for example, in Duncan Patent No. 1,026,246 patented May 14, 1912, and devices of this character may be utilized with this invention. Furthermore, in some instancestype characters are formed on suitable stencil paper, carried by alframe of card- .board or other material, and suitable means are provided in printing machines through which 'such devices are fed to, apply ink on the type characters and afford a printing impression on a sheet or the like and printing devices of this kind may be used with the present invention.

The printing and control device shown in Fig. 3 includes a carrier or, as it iscalled in'the art, frame I having, in this instance, a metallic plate 2 removably retained thereon by fixed retaining devices 8, a head 3' at the lower edge of the frame, and yieldableor 'depressible retaining tongues I. :When one or the other of the tongues l isdepressed the plate 2 may be slid endwise from the retaining devices 3 and the'bead 3. Type characters T are, in this instance, embossed inthe metallic plate 2 so as to appear in relief onone face thereof and in intaglio on the opposite face, impressions being made from the relief faces of the type characters T when the printing andcontrol device D is fed into printing relation with the platen P, Fig. 1, in the machine. The printing and control device shown in Fig. 3 also bears an identification card 5 on which an impression is made from the type characters T so that the data which may be printed from the type characters T may be read easily, this facilitating handling of the device D. This card 5 is removably retained on the frame I above the plate 2 thereon by suitable retaining devices I and a bead 8 at the top of the frame. A control card 8 is retained on the frame I atone side of the card 5 by the retaining devices 9 and the bead 8, a retaining device 1 being interposed between the cards 5 and 6, and the underlying portion of the frame I are adapted. to have perforations formed therein in accordance with the code shown in Fig. 4 so as to afford control means or representations of data, and such perforations a in which the card .6 and the underlying portion While a 'wide of the frame I are perforated is not essential to an understanding of the present invention it may be well to note that when data represented by perforations in the card 6 need be changed all that need be done is to remove this card 5 and substitute another unperforated card therefor and this new unperforated card-may then be perforated to afford representations of .the data that are to be substituted for that which has been previously incorporated in the device D. It may be that in sodoing the frame I will also be perforated and this will be done in all instances where the newly formed perforations are located differently than-the supplanted perforations, the

supplanted and used perforations, in such instances, being covered and rendered ineffective by unperforated portions on the new card 6.

In Fig.6 of the drawings a, fragment of a proof sheet 8-2 that may be produced in the machine is illustrated, and the characteristics ofthis proof sheet and the means in which it is produced will.

be explained more fully hereinafter to the extent necessary for a, complete understanding of the present invention. It may be here pointed out however, that in the production of the proof sheet 8-2 a pager and proofer such as that shown in my copending application, Serial No. 320,778,

filed February 20, 1940, may be associated with the machine shown in Figs. 1 and 2.

The dividend check or sheet S is, in the present instance, severed from a web W, Figs. 1 and 2, that is withdrawn from a roll R which is rotatably supported in the stand In, which, in the machine as shown in Fig. 1, is provided. at the right-hand end of the machine. The web W is led from the roll R to a suitable web withdrawing device contained within the housing N, Fig.

- which, as shown in Fig. 2, is provided longitudinally along the top iii of the machine frame IS. The sheets S thus severed from the web are fed along the guideway G to the left in Fig. 2 by suitable sheet advancing means such as driven rollers I65 so that the leading edges of such sheets S are advanced into engagement with stop fingers [9i and 2| l. During the time that the leading edge of a sheet S is engaged with the stop finger l9l, printing means included in a multiplying mechanism M, and which include a platen means 250, are operative to print variable data, as V, Fig. 5, on the sheet, and after such an impression has been made the stop finger I9] is retracted from engagement with the leading edge of the sheet which thereupon advances into engagement with the stop finger 2| I. When thus engaged with the stop finger II I, the sheet S is disposed beneath a platen P which at predetermined times in the course of operation of the machine is operated to make a printing impression on the sheet S directly from the type characters T of the printing and control device D from which the variable data V of this sheet was derived. The printing and control devices D are advanced through the machin in a step-by-step manner such that each deviceD comes to rest on an anvil located beneath the platen P so that when the platen P is moved toward a printing and control device resting on such anvil a printing impression'is made on the sheet from printing characters embossed or othe"wise formed on the device. Where the type characters on the printing and control device are formed by em- I bossing. such printing impression is made through the intermediary of an inked ribbon interposed between the embossed type characters and the portions of the sheet upon which the printing impression is to be made. After an impression has been made on a sheet by the platen P the stop finger 2 is retracted from introduced into the magazine H from which the devices are withdrawn one at a time to be passed through the machine into detecting and printing positions therein. After passing through these positions the printing and control devices pass into mechanism which operates to direct the devices into one or the other of the drawers J, Fig. 1, in which such devices are stored when not in use and from which they are removed when they are introduced into the magazine H. In the machine in which the :present invention has been illustrated the lowermost printing and control device D in the magazine H is removed therefrom and is fed forwardly through positions or stations in the printing device guideway. One of these stations constitutes a sensing station II,

- 8 Fig. 7, at which the control areas on the printing and control devices are sensed to effect set-up of the multiplying mechanism M, and another of which stations constitutes a printing station III, Fig. 7, wherein the printing devices come to rest on an anvil 264 and impressions are made directly from the type characters provided on the printing and control devices.

In the course of operation of the machine the desired feeding movement is imparted in a step by step manner to the printing and control devices Din a manner fully described in my aforesaid copending application Serial No. 221,841 filed July 28, 1938, there being an actuatin mechanism 280 (Fig. 2) which for each desired feeding movement imparts a reciprocatory stroke to suitable carrier bars or other means mounted in the printing device guideway.

When the printing and control devices D are moved to station III, in the desired printing position above the anvil 264, impressions are made therefrom by the platen P, and this platen P may also make impressions from the other printing mechanisms such as a means for printing the number N on the sheet S, as explained in detail in my copending application Serial No. 221,841. In such an instance the additional impressions are made by printing mechanism which cooperates with an end portion such as the left hand end portion of the platen P as viewed in Fig. 12.

As has been explained above, the number of type characters that may appear on various printing and control devices may vary widely from device to device, and in order to prevent a heavy impression being made when only a few type characters appear on a printing and control device and a light impression being made when a large number of type characters appear. the present invention has provided a platen arrangement which will make uniform impressions even under conditions entailing extreme variations in .the number of type characters.

- One factor which contributes to the production of uneven impressions is spring, that is, twisting, in the member supporting the impression making member which, in the present instance, is the platen P. This may be overcome, to a substantial extent by employing relatively rigid members to support the impression making member such as the platen P and in the present instance a pair of relatively heavy and

substantial side members

638 and 539, Figs. 7 and 12, are provided. The members are substantially U-shaped and are formed from relatively thick material. The U-shaped configuration of the side member 538 is afforded by substantially parallel arms 540 and 5H, and an interconnecting arm 2,

similar parallel arms 543 and 5, Fig. 12, and a similar interconnecting arm 5", constituting the side member 538.

tary structure which comprises the movable portion of the impression making means of which the platen P is a part.

it is well understood in the art to which printing machines of the kind to which this inventions pertains find their principaluse that it is essential that the face of an impression member such as the platen P be in strict parallelism with the face of a printing and control device hearing type characters from which an impression is to be made, this preventing smearing and kindred objectionable conditions in impression oper-' ations. This is best attained by providing the point of pivotation of the movable part of the impression means in the plane in which the faces of the type characters from which impressions are to be made will lie and in the present machine this is accomplished by securing blocks 552 to the upper edges of the

side plates

254 and 255 which'form part of the machine frame and are shown in Figs. .7 and 12. 'V-shaped notches 555 are providedin the blocks 552 and the apices of these V-shaped notches lie in the aforesaid plane in which the type characters will lie when a printing and control device is disposed on the anvil 255.

Blocks 555 are secured to the arms 552 and 54.5 of the side members 535 and 539 and these blocks are formed to provide knife edges 558, which are seated in the V-shaped notches 554 so that these knife edges rest in the respective apices afforded by these V-shaped notches 555. Such mounting of the movable portion of the impression means enables this movable portion to be moved with minimum friction, and this arrangement insures that minimum wear will occur in the course of long use of the impression means. Furthermore, the seating of the knife edges 558 in the apices of the notches 555 assures that the point of pivotation of th movable part of the impression means will lie in the plane above described.

. While the rigid construction above described and the assurance that the face of the impression member will lie in the proper plane attribute to the production of the desired uniform impressions, this can be further assured by causing the impression pressure to be effected by a squeezing action which may be the resultof the application of retroactive forces and in order to accomplish this I resort to a hydraulic system for applying the impression pressure.

It has been stated heretofore that the printing and control devices rest on'an anvil 264 during the time impressions are made therefromby the to squeezing and the utilization of the retro active forces when a hydraulic, system is employed, I form a cylinder 559, Fig. 7, in the underside of the anvil 254, a piston 566 being reciprocal in this cylinder and having th rounded outer end thereof positioned to bear upon the bar 550 extended between the arms 54! and 544 of the

side members

538 and 539. Thus when hydraulic pressure is impressed on the piston 560 this pressure is effective on the bar 559 to pivot the

side members

538 and 539 about the knife edge pivotal supportsthereof, and the force effective on the piston is also effective on the anvil and in this way the pressure incident to the impression making operation is a utilization of retroactive forces.

Hydraulic pressure is impressed upon the piston from a pump, generally indicated by 56| in Figs. 1 and 7, which includes an outer casing 562 welded orotherwise suitably secured to a bracket 563 that is pivotally mounted on a tie rod 239, Figs. 1 and 7, intermediate sections of the spacing sleeve 355, the positioning of this bracket intermediate these sections of the sleeve preventing longitui6 dinal movement of the bracket 563 along the tie rod 239. An arm 564 depends from the bracket 563 near the end thereof and an adjusting bolt 565 is mounted in the lower end of the arm 564 and engages a flange on the upright 259 to limit pivotal movement of the bracket about the tie rod 239, this adjusting bolt enabling the outer casing 562 of the pump 56! to be adjusted into a proper vertical position.

The outer casing 562 of the pump 56! aflords a guide for a piston 566 which is bifurcated, as indicated at 561, at its upper end, and a roller 568 is rotatably mounted on the shaft 569 in this bifurcation. A shaft 510 is journaled in suitable bearings, Figs. 7 and 9, provided at the upper end of the casing 562 and has a cam 5'" fast thereon in alignment with the roller 568, the configuration of this cam being'such that in each revolution of the shaft 515 the piston 566 is reciprocated in the outer casing 562, retroactive force being applied on the piston 566 to maintain the roller 568 in engagement with the cam 51lfby a spring 512 mounted in a relieved part of the piston in the outer casing 562, this spring extending to a shoulder 515 formed on the outer edge of the cylinder 515, that portion of this cylinder immediately beplaten P and in order to realize the above referred low the shoulder 513 being screw-threaded into the lower end of the casing, as indicated at 515. The head of the cylinder 515 is afforded by a block 516'that is bolted to the cylinder and which hasa port 511 therein, the outer tube 518 communicating with this port 511. The outlet tube 518 leads to a port 581 provided in abloek 532 secured to the rear side of the casting 263 which includes the anvil 266. The port 58! leads to a passage 583 in the block 552 which leads to the inlet port 584 that opens into the cylinder 555 above the piston 56!] therein.

The part of the cylinder 515 that is cut away to define the shoulder 513 and the cut-away part on the piston defining a space to receive the spring 512 cooperate to afiord a storage chamber or reservoir 519 which communicates with that portion of the cylinder 514 in which the lower end of the piston 556 is reciprocal through ports 586. The purpose of the reservoir 515 is to enable a greater quantity of a suitable hydraulic oil to be introarea in the cylinder 559 above the piston 565,

communication of this system with the reservoir 519 being established with the reservoir 515 through the ports 580. The additional supply of hydraulic liquid or oil in the reservoir 519 is sufficient to eliminate the necessity of replenishing the v supply of hydraulic oil in the above described system except at infrequent intervals.

When the cam 51| engages the roller 568 and the piston 566 is forced downwardly this piston quickly moves from its normal at rest position shown in Fig. 7 and in the very first stages of this movement closes the ports 580, thereby trapfping in the above described system a quantity of hydraulic oil sumcient to entirely fill this system and consequently as the piston 566 continues its downward movement the pressure impressed on the oil by the piston 566 is impressed on the piston 565, the difierence in the diameter of the

cylinders

515 and 569 and the diiierence in stroke of the

pistons

566 and 566 affording a hydraulic lever which causes the piston 560 to exert su stantial pressure on the bar 550. A

The platen P is *adjustably mounted at the free ends of the arms 5A0 and 5 33, this adjustable mounting being described in further detail offset will be produced on the face of the platen P, and this is objectionable as is well understood in the art. Therefore a detector is provided in association with the platen P which actuates mechanisms that cause the movement of the platen P toward a printing and control device on the anvil 284 to be interrupted in event no sheet overlies the ribbon 11% whereby the formation of an-oifset on the face of the platen in the absence of a sheet is avoided. There are instances, however, where the platen P is to make an impression operation even though no sheet as S is positioned therebelow. Hence, the means under control of the aforesaid detector are arranged to be operative only when, in an impression operation of the platen; a sheet as 8 should be disposed therebelow.

This detector in the present instance includes a spring-pressed pin 535 (Figs. '7 and 12) mounted in the plate 588 of the platen structure out of alignment with the inked ribbon IE!) but in a position to be aligned with a sheet which should overlie this inked ribbon. An opening 581, Fig. 12, is provided in the bed plate 108 in alignment with the pin 585, and when the platen P moves downwardly the pin B85 moves toward the opening 587. If a sheet overlies the opening 581 the pin is prevented from moving thereinto and in the course of downward movement the pin merely compresses the spring effective thereon.

If, however, a sheet does not overlie the opening 581 then the pin 58! passes thereinto and. engages a block 58! of insulating material on the upper blade 5 of a pair of switch blades, the other blade of which is indicated by 590, these switch blades being mounted on blocks I of insulating material in spaced apart relation and being supported on the underside of the bed plate I. When, therefore, the pin 585 engages the block 588, contacts on the blades 588 and 59!! are engaged to close an electric circuit which includes the solenoid 592, Fig. '7, provided a sheet as S should be below the platen P at this time, circuit to the solenoid 592 being open at a point other than the contacts on the blades 58! and 580 when an impression operation of the platen is not to be effective on a sheet as S. Such circuit arrangement is described in full detail hereinafter.

Energization of the solenoid 592 retracts the core 591 thereof, Fig. '1, to withdraw the pin 588 on this core from alignment with the end of the piston 59! reciprocally mounted in a cylinder 600 in the block 582, a spring ill normally actin on this piston 599 to urge it into the position in which it is illustrated in Fig. 7 where it can be engaged by the pin 82 to be retained in the said position. The piston 599 is relieved as indicated at. 652 to afford a passage through which communication isnormally established between the ports I and 583. Thus the passage 602 and therefore, in effect, the piston'598 are part of the above described hydraulic system. Now when the solenoid 592 is energized by the engagementof contacts on the blades E89 and 590 and the pin 598 is retracted from engagement with the end of the cylinder 600, the hydraulic pressure, being 12 applied on the piston 598 at this time will overcome the eifect of the spring 6M and will force the piston 599 through the cylinder 600, to the right as viewed in Fig. '7. Such movement of the 5 piston 599 through the cylinder 600 increases the capacity of the above described hydraulic system in such a way that the pressure impressed by the piston 586 is rendered ineffective to bring the platen P into a position whereat it would be effective to make an impression from a printing and control device on the anvil 2 below the inked ribbon 13b. The piston 599 can only move through the cylinder 600 to relieve this pressure in those instances where the presence of a sheet above the ribbon IRb does not prevent the pin 585 from passing into the opening 581 and hence the above described arrangement constitutes a safety which prevents the formation of offsets on the face of the platen P.

It has been explained heretofore that it is desirable that the platen P make uniform impressions irrespective of the number of type characters provided on the various printing and control devices moving into the printing and control position below the ribbon IE1), and it has been explained that this in a great measure is attained by utilizing retroactive forces which are effective to apply printing pressure on the platen P. This is realized in the present instance by providing the cylinder 559 in the anvil casting 253 directly below the anvil and by applying the platen P pressure directly above the anvil so that the force resisting the piston 560, which applies the platen pressure, is impressed on the anvil 264 and this force is opposite to or retroactive with respect to the force imparted through the platen P. This arrangement results in a printing operation entailing what'is, in effect, a squeezing action. I

It has also been explained that by avoiding a rigid structure for supporting the platen P those difliculties attendant to springing in such a structure are reduced to a minimum and since such a structure is utilized in the present machine the production of uniform impressions is additionally 45 assured.

To further insure that uniform impressions will be made in various printing operations of the platen P, I stop the platen P in an identical position with respect to a printing and control device 60 on the anvil 2 in each impression making operation. To this end the lower arms Eli and 5,

Figs. 7, 14 and 15, are so arranged that their outer ends extend above the girder 26 l When the platen is in an upper or inoperative position, in which it is shown in Fig. 14, the arms 5 and 5 are free of the upper edge of the girder 26L but when the platen P attains its operative or impression making position, in which it is shown in Fig. 15, the arms I and I5 engage and rest 00 upon the upper edge of the girder 26!. The parts are so arranged that at the time the arms ill and i so engage the girder "I, the platen P will be in parallel relation with respect to the surfaces of type characters on a printing and control device supported by the anvil 2M and at the time this parallel relation is attained the face of the platen P will be in impression making relation with such type characters. It will be manifest that the engagement of the arms I and 5 withthe girder .28! at this time effectively prevents the platen from moving beyond the above described parallel relation with the type characters and this further insures that uniform impressions will be produced by the platen P in various impression making operations thereof.