US3232221A - Explosive marking and printing apparatus - Google Patents

Description

Feb. 1, 1966 P. A. STOWELL EXPLOSIVE MARKING AND PRINTING APPARATUS Filed June 28, 1963 OXYGEN SUPPLY 9 HYDROGEN SUPPLY PHILIP A, STOWELL o 5 0 EL 00 0O) GF 0 EL EL 0 E 6 0 V EL A CL V N 7 Dn T. G G 0 U [L P H G J [L N I EL 4 P R E LU s 0 0 V 0 H H M N U DI I H m A l 1.. WW CL P W 0 I ST U V HDI MW rr. EL I P o E w Aw Wm Nm U Z 0 P f K N 0 0 R M H m R G EL [L m GR DH N R NE EO N NG R A G B R CL [L D G mm m 1 o r R I 2 1 7Q w M A v 5 United States Patent 3,232,221 EXPLOSKVE MARKZNG AND PRENTHJG APPARATUS Philip A. Stowell, Paoli, Fa, assignor to Burroughs Corporation, Detroit, Mich, a corporation of Michigan Filed June 28, 1963, Ser. No. 291,411 6 Claims. (Cl. 101-93) This invention relates to marking and printing apparatus and more particularly, to a high speed marking-printing device utilizing the pressure of a wave generated by the explosion of unstable material in a cavity by an electrical sparkeifeotive to cause an element to mark or print on a record medium.

Heretofore high speed marking and printing devices have: been employedin computer systems utilizing the pressure of the shock wave generated in a small cavity by an electrical spark discharge. The work of Early and Orr as-described in their patent, U.S. 2,737,882, entitled High. Speed Printing and Perforating Machine, and assigned tothe same assignee as the present invention, indicate the energies required for perforating and embossing of characters in paper tape. The nature of the spark discharge in such devices is such as to produce extremely high temperatureshock waves of high peak pressures. It has been found difficult however, to efliciently harness such high temperatures and pressures since much of the heat produced is lost by radiation and absorption in the walls of the cavity, and much of the pressure is lost by gas leakage in a direction parallel to the record medium.

It is an object of this invention therefore to provide an improved marking apparatus which avoids one. or more disadvantages of the prior art arrangements and which has improved operating-efiiciency.

It is a further object of this invention to provide in a printing device a movable member which is accelenated by means of the pressure explosively produced in the device.

In accordance with a preferred form of the invention there is provided a member having an explosion chamber in theform of a cylinder, and containing at one end thereof a piston which is normally restrained against the open end of the cylinder by springs. The fuel for the device which may be in the form of an explosive mixture of'gases such as hydrogen and oxygen, is admitted to the cylinder by suitable. ports opening thereinto. A type Wheel carrying raised type is spaced from the piston in a manner'to permit passage of a record medium and ribbon thcrebetween. When a selected character on the type wheel is inits correct position behind the paper to be printed upon, the explosive charge in the cylinder is detonated: The explosion occurring in the cylinder drives thepiston outwardly until it is arrested by impacting against the record medium to cause the latter to be driven against the ribbon and the raised hard type face forming an' impression of the selected character upon the record medium.

For a better understanding of the present invention together with other and further objects thereof, reference is hadto the. following description taken in connection with the accompanying drawings and its scope will be pointed out-inthe appended claims. In the drawings:

FIG.- 1 is a schematic view partially in section showing the variousparts of the printing device;

FIG. 2 is a sectional view taken along the li-ne-2'-2 of FIG. 1 showingorifices leading into the piston chamber;

FIG. 3 is a partial view of a modified form of the invention.

Referring to FIG. 1 of the drawing there is shown a two-part housing 12 comprising a base portion 13 and a head portion 14, which when joined together form an explosion chamber in the form of the cylinder 15. A piston 16 is slidably received in'theforwardend of the cylinder and is restrained as by springs 17. The fuel for the explosion in the cylinder maybe a hydrogen-oxygen mixture, which gases are admitted from a hydrogen supply 18, and an oxygen supply 19. The gases, separately admitted to the cylinder 15 by means of ports or orifices 2t and 21 formed within the base member 13, maybe detonated by a spark discharge device 23 which is inthe form of a coaxial spark plug. A typewheel 25 having a font of raised type characters 26 about its periphery, is spaced from the free'end of the piston lose as to provide a guide, gap or passage for a recordmedium 27 and a marking ribbon 28. The type wheel is normally rotated at high speed, by means not shown, so that when the de sired character is in line with the piston 16, the explosive charge within the cylinder 15 is detonated. The resulting explosiondrives the piston 16 at a high rate of speed forwardly toward the type wheel until it is arrested by impacting against the record medium 27' on which printing is to occur. The ribbon 28'disposed behind the record medium and in front of the type wheel 25, causes the desired mark to be made when the record medium and ribbon are thus driven against the raised hard type face'26.

Considering the housing 12 in greater detail it is seen that the base member 13 includes a circumferentially out.

or grooved portion 3t defining a portion of a hydrogen inlet manifold, see FIG. 2, and a like formed circumferential groove 3.1 is provided to constitute a portion of an oxygen inlet manifold. In each case the grooves 30 and.

31 are less than a semi-circle in their circumferential extent and are separated from each other by the solid or ungrooved portions 32 and 33, as seen in FIG. 2. The rear portion of cylinder 15 in base member 13 is threaded at 34 to receive thumbscrew 35 whereby the chamber volume of the cell may be varied to obtain a fine adjustment relative to the energy content of the explosion. The forward end 36 of the base member is of a reduced diameter corresponding with the inner diameters of the grooves 3 3, 31 and is drilled radially toform the aforementioned orifices Ztl and 21. The head. member 14 is recessed as at 37, and includes a dimension which corresponds to the outer diameters of grooves Pill, 31. The outward face 38 of the reduced portion 3.5 of base member 13, bottoms on the face 39 of recess 37 to thereby form a hydrogen inlet manifold 40 with groove 30 and an oxygen inlet manifold 41 with groove 31. Bolts 42 secure the base 13 and head 14 together in the manner shown.

Piston 16 is formed to include an elongated skirt 43 which rides within cylinder 15 and is effective when in its nonaprint position, to seal the exhaust ports 44- formed in the head member 14. As the piston advances as a result of the charge in the cell being detonated, the skirt 43 uncovers the exhaust ports 44'thus permitting the compressed hot gases in the cylinder to escape.

The forward end of the piston includes a reduced head portion 4-5 which serves to push the record medium and ribbon against the type face 26. The piston 16' further includes a radially extending skirt 46 which extends be yond the reduced or neck portion 4-7 of the head 14. Theaforementioned springs 17 are thus secured at one of their ends to the outwardly projecting peripheral edge of the skirt 46 and'at their inner ends to the face 48 of the member 14.

In order to introduce the desired proportions of-hydrogen and oxygen into the cylinder for an explosion of adequate energy, means are provided for controlling the flow rates of the two gases separately. For this purpose the oxygen supply 19 with conduit 50 leading to. the aforementioned oxygen inlet manifold 41 includes an oxygen regulator valve 51 in the conduit. In a similar manner, the hydrogen supply designated 18 with conduit 52 leading to hydrogen inlet manifold 40, includes a hydrogen regulator valve 53, and in addition, a normally closed solenoid actuated valve 54, to further control the hydrogen supply.

The latter solenoid valve d has been found desirable and is provided for the following reason: When the cell detonates, incoming gases combine to burn in the cell until cut-off. Thus the unit cannot fire again until the flame is extinguished. The flame can be blown out, or put out by shutting off the hydrogen flow. If the oxygen alone is shut off, the hydrogen will continue to burn in the air outside the cell. It is possible to interrupt both the hydrogen and oxygen supplies but this is not essential from the standpoint of functionality. The abovementioned two-way solenoid actuated valve 54 is therefore included in hydrogen line 52. The solenoid valve includes a housing containing a coil winding 55, a plunger 56, apertured as at 57, to permit flow of hydrogen through conduit 52, and a suitably apertured fitting 53 surrounding conduit 52 and receiving plunger 56. When the aperture 57 of plunger 56 is axially aligned with conduit 52, as illustrated, the plunger 56 is in its open position and hydrogen under pressure from supply 18 is fed to the combustion chamber 15. Upon a print signal being received by the printing device to fire the spark plug 23-, the plunger 56 of solenoid 54 is tie-energized and the spring 59 thereby advances the plunger to the right to momentarily cut elf the flow of hydrogen into conduit 52. Thereafter solenoid coil 55 is re-energized to restore the plunger 56 to its open position relative to line 52 and against the action of spring 59 so that the cell is once again in its ready state. Due to the fact that oxygen has a greater viscosity than hydrogen it has been found necessary to provide as shown in FIG. 2 of the drawings, a greater number of oxygen inlet ports or orifices 21 than the number of hydrogen inlet orifices 20. This construction helps to insure that there will not be an excess of one gas over that of the other in the mixture, relative to the proportions which are desired.

It has been found desirable prior to firing the cell that the same be preheated, which preheating is accomplished by the use of an electrical cartridge heater 60 received within an annular recess 61 in the rearward portion of the base member 13. The heater is shown connected in series by means of leads 62, 62a with a thermostat 65, the same being supplied with a current from AC. voltage source 63. The thermostat extends within the side walls of the base member 13, so that a portion thereof is fiush with the walls of cylinder 15. When the combustion chamber has been brought up to an adequate temperature, the thermostat 65 cuts off additional current flow to the cartridge heater 60, and permits further current flow only as may be needed to maintain adequate operating temperatures, above the boiling point of water. The use of the abovedescribed heater has been found desirable because the products of combustion of hydrogen and oxygen are water. The same may thus condense on the surfaces which are below boiling point at atmospheric pressure. Hence, it is necessary to insure that piston 16, cylinder 15, coaxial spark plug 23, and all remaining parts in the explosion chamber which come in contact with the products of combustion be raised to a temperature sufiicient to assure that such condensation does not occur.

In operation the explosive printing device functions as follows: A digital character code, for instance representing a desired character, is applied from a source not shown to the buffer and trigger generator circuit device 70, which translates this character and determines a necessary time interval which must lapse after receiving a synchronizing pulse from the type wheel in order that the explosion may occur when the desired type face is in its correct position. After the synchronizing pulse from the type wheel has elapsed, a trigger pulse is applied to the wide range pulse generator 72, which then functions to generate a standard pulse for application to a flip flop circuit device designated 74. The pulse simultaneously proceeds to a pulse delay circuit indicated at 76 and also to a pulse operated relay device designated 78. The flip flop circuit device 74 immediately flips into the ZERO state and remains there until a delay pulse from the pulse delay circuit '76 arrives and flips it back into the ONE state. This generates a pulse of standardized duration which acts as a trigger to the high voltage pulse generator circuit device 30. For the duration of the trigger pulse the high voltage generator device 80 connected to the coaxial spark plug 23 by leads 81, 82 with resistor 83 in lead 81, puts out a pulse of suflicient voltage to cause a useful spark across the spark plug 23. The source of this voltage is a high voltage power supply designated 85.

The simultaneous arrival of the pulse from the wide range pulse generator 72 to the pulse operated relay 78, causes the same to interrupt the hydrogen supply by interrupting the holding current to coil 55 of solenoid valve 54. The pulse operated relay circuit 78 as shown, includes an inductor coil 79 suitably connected to ground. Application of the pulse from the wide range pulse generator 72 applies this pulse across inductor or coil 79. This causes contact 79A of inductor 79 to open thereby interrupting the current flow from the AC. voltage supply 63. The latter current flow to coil 55 of solenoid 54 is thus interrupted which thereby enables spring 59 encircling solenoid plunger 56 to move the same to the right to thereby block the flow of hydrogen to the cell which has since been detonated. Thereafter a delay pulse from the pulse delay circuit 76 through inductor coil 79 closes contact 79A to thereby permit current to flow from the A.C. voltage supply 63. The solenoid coil 55 is thus re-energized and plunger 56 is moved against the action of spring 59 to its initial open position so that aperture 57 is aligned with conduit 52 to thereby permit the combustion chamber to be charged with hydrogen for a subsequent cycle of operation.

In accordance with a modified form of the invention as shown in FIG. 3, the head of the piston 43 is shown as including a male die element 85 which cooperates with a female die member 87. In the non-print position of the piston 43, the same is spaced from member 87 to permit passage of a record member or work-piece 89 which is adapted to be punched therebetween. The female die member 87 is apertured as at 90 to receive the reduced die portion 85, as shown. In all other respects the construction of the combustion cylinder may be similar to that described in FIG. 1 above. Depending on the material to be perforated or punched, as designated by perforations 91 in the material 89, the energy content of the explosion may be varied by adjusting the chamber volume or" the combustion device. This may be done by rotation of the thumbscrew 35 as seen in FIG. 1 above.

While there have been described what are at present considered to be the preferred embodiments of this invention, it will be obvious to those skilled in the art, that various changes and modifications may be made herein without departing from the invention. For example, although cylinder gases may be used for fuel and oxygen with this device, it also is within the purview of this invention that these gases be generated by electrolysis of water. This would require merely an electrolytic cell and an electrical rectifier. It may be further seen that this device may also be used if desired, for such other industrial operations as stamping, embossing or as an actuator of a type where very high rates of acceleration are desired. It should further be apparent that a plurality of such explosion chambers 15 having movable piston elements '16, may be disposed in a single line across the page and adapted to cooperate in parallel with a rotata-ble drum having columns of circumferentially disposed type therearound to mark or otherwise print out a completeline of characters simultaneously. Alternatively, itis equally within the purview of this invention to provide a single combustion cell and piston as illustrated, which may be mounted for movement along a line par-allel to such a drum having type characters therearound and in which one character is printed at a time, with successive characters being printed or marked until a complete line is made.

The principal advantages of thisdevice are the very high rates of acceleration obtainable in the piston because of the large force which can be applied thereto as compared to the force that may be available in electrically operated solenoids and its low mass compared to the mass of a solenoid plunger. In addition, very low currents are required to initiate the explosion in the unstable gases by means of the spark plug and as a consequence there is little erosion of the electrodes. Also, by employing a piston device to seal the explosion chamber, greatly improved efiiciencies are obtained. It is therefore aimed in the appended claims to cover all such changes, modifications, as fall within the true spirit and scope of this invention.

What is claimed is:

1. Printing apparatus comprising, a body having an elongated cavity for containing an explosive mixture of gases therein, said mixture when exploded forming a reaction product which condenses at ambient temperature, heater means received in said body for preheating the body to prevent said condensation, a piston member movable within said cavity, a member juxtaposed to the free end of said piston and in closely spaced relationship therewith to permit a record medium to be inserted therebetween, separate value and conduit means for introducing and regulating the flow of said gases into said cylinder in accordance with their viscosities, spark means extending into said cylinder, and circuit means connected to said heater means and including a source of power connected to said spark means for producing an explosion of the gas in said cavity to thereby accelerate the piston which is caused to mark the record medium, venting means associated with said cavity for removing said reaction product, and thermostat means associated with said body and connected with said heater means.

2. Marking apparatus comprising, a body having a cavity in the form of a cylinder therein, means for varying the chamber volume of said cavity, separate valve and conduit means for controlling the fiow of hydrogen and a continuous flow of oxygen separately into said cylinder for mixture within the latter, said conduit means including means for regulating the flows in accordance with the viscosities of the oxygen and hydrogen, spark discharge means extending within one end of said cylinder, a piston mounted for movement between mark and non-mark positions within the other end of the cylinder and having a portion projecting therefrom, a met ber positioned in spaced relation from the projecting portion of the piston to permit passage of a record medium therebetween, circuit means including a source of power connected to said electric discharge means and operable for producing an explosion in said cylinder such that energy is transferred to said piston to cause the same to mark, heater means for preventing condensation of the reaction product of the explosion, exhaust means associated With said cylinder for removing the reaction product of said explosion, bias means associated with said piston and said body for returning said piston to its nonmark position, and means associated with said valve and conduit means for the hydrogen and actuated by operation of said circuit means for momentarily interrupting the flow of said hydrogen.

3. Printing apparatus comprising, a body having an elongated cylinder therein, a piston mounted for sliding movement in one end of the cylinder for effecting printing on a-recordrnedium, means for separatelyintroducing.

a plurality. of ga-ses'in-theform of hydrogentand'ioxygenw within the cylinder to formxan explosive mixture therein,- said introducing means including inlet port means having a first volume for introducing the hydrogen into the cylinder and inlet port means havingga secondjvolume which is greater than said first volume for introducingtheoXygen into the cylinder, means for controlling the. flow. of said'gases into the cylinder, a spark device exposedto theinterior of the cy'linder, a surface spaced fromthe piston and in opposedrelationshi-p thereto for permitting saidrecord medium to be guided therebetween, circuit means including a source of power connected'to said spark device for producing a controlled explosion in the cylinder such that the explosive reaction transfers energy to the piston to accelerate it and cause it to effect printing on the record medium, heater means for preventing condensation of the reaction product of the explosion, and venting means for removing the reaction product from the cylinder.

4. High speed printing apparatus comprising, a body having a cylinder therein, a first valve for controlling the flow of hydrogen into the cylinder, a second valve for controlling a separate continuous flow of oxygen into the cylinder .to mix with the hydrogen, inlet port means having a first volume for conducting hydrogen coming from the first valve into the cylinder, inlet port means having a second volume which is greater than said first volume for conducting oxygen coming from the second valve into the cylinder, spark discharge means exposed to the interior of the cylinder, a piston slidably mounted in the cylinder for movement between print and non-print positions, said piston having an end portion projecting from the cylinder and a surface on the end portion which seals the cylinder when the piston is in its non-print position, a plurality of type characters, said type characters and said body being relatively movable at high speed to position a character selected for printing in spaced relation to the projecting portion of the piston to permit passage of record means therebetween, circuit means including a source of power connected to the spark discharge means for producing an explosion in the cylinder such that energy is transferred to the piston causing the piston to move against the record means and the record means to move against the selected type character, exhaust port means normally closed by the piston and opened by movement thereof for removal of the by-products of the explosion, means biasing the piston to its non-print position, means for preventing condensation in the cylinder, and a third valve under control of said circuit means for interrupting the flow of hydrogen from said first Valve.

5. High speed printing apparatus according to claim 4 wherein said circuit means includes a pulse generator operable in timed relation with said relative movement between said body and said type characters for simultaneously triggering operation of said spark discharge means and said third valve.

6. Marking apparatus comprising, a body having an elongated cylinder, means for varying the chamber volume of said cylinder, a movable marking member received in said cylinder, separate valve and conduit means for separately and proportionately introducing a plurality of gases into said cylinder to form an explosive mixture therein, said mixture when exploded forming a reaction product which condenses at ambient temperature, means for heating the cylinder to an operating temperature above the boiling point of water to prevent said condensation and for maintaining the cylinder at said operating temperature, a spark device extending interiorly of said cylinder, a spaced surface in opposed relationship to said marking member to permit passage of a record medium therebetween, circuit means including a source of power to said spark device for producing an explosion in said cylinder such that the explosion reaction of the gases 7 8 accelerates the marking member to cause it to mark said 2,883,927 4/1959 Egbert 101-4 record medium, and venting means for removing the re- 3,003,418 10/1961 Young 1014 X action product of the explosion. 3,015,263 1/1962 Lounsberry et a1. 101-19 n 3,122,039 2/1964 Sowers 101-3 X Rmrences Cited by the Examiner 5 3,149,562 9/1964 Wilkins et a1. 101 93 UNITED STATES PATENTS 9/1925 Gibson 1O1 4 OTHER REFERENCES 8/1946 Ryan 101-4 X Chemistry of Engineering Materials; R. B. Leighou; 3/1951 Triplett et a1. 101-4 McGraw-Hill Book Co.; 1931, copy Group 470, Class 7/1952 Cook 101 1012 10 101-DK. 3/1956 Early et a1 101-19 X 10/1957 D l 1 1 1 WILLIAM B. PENN, Primary Examiner.

Claims (1)

1. PRINTING APPARATUS COMPRISING, A BODY HAVING AN ELONGATED CAVITY FOR CONTAINING AN EXPLOSIVE MIXTURE OF GASES THEREIN, SAID MIXTURE WHEN EXPLODED FORMING A REACTION PRODUCT WHICH CONDENSES AT AMBIENT TEMPERATURE, HEATER MEANS RECEIVED IN SAID BODY FOR PREHEATING THE BODY TO PREVENT SAID CONDENSATION, A PISTON MEMBER MOVABLE WITHIN SAID CAVITY, A MEMBER JUXTAPOSED TO THE FREE END OF SAID PISTON AND IN CLOSELY SPACED RELATIONSHIP THEREWITH TO PERMIT A RECORD MEDIUM TO BE INSERTED THEREBETWEEN, SEPARATE VALUE AND CONDUIT MEANS FOR INTRODUCING AND REGULATING THE FLOW OF SAID GASES INTO SAID CYLINDER IN ACCORDANCE WITH THEIR VISCOSITIES, SPARK MEANS EXTENDING INTO SAID CYLINDER, AND CIRCUIT MEANS CONNECTED TO SAID HEATER MEANS AND INCLUDING A SOURCE OF POWER CONNECTED TO SAID SPARK MEANS FOR PRODUCING AN EXPLOSION OF THE GAS IN SAID CAVITY TO THEREBY ACCELERATE THE PISTON WHICH IS CAUSED TO MARK THE RECORD MEDIUM, VENTING MEANS ASSOCIATED WITH SAID CAVITY FOR REMOVING SAID REACTION PRODUCT, AND THERMOSTAT MEANS ASSOCIATED WITH SAID BODY AND CONNECTED WITH SAID HEATER MEANS.

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