US3735771A

US3735771A - Pneumatic reader for perforated media

Info

Publication number: US3735771A
Application number: US00103223A
Authority: US
Inventors: H Panissidi
Original assignee: International Business Machines Corp
Current assignee: International Business Machines Corp
Priority date: 1970-12-31
Filing date: 1970-12-31
Publication date: 1973-05-29
Anticipated expiration: 1990-05-29

Abstract

A pneumatic, perforated tape, intermittent motion reader is connected to a pneumatic-to-hydraulic interface in a hydraulic control system. A hydraulically controlled pneumatic purge system is provided for ejecting or purging foreign matter from the pneumatic reading lines between successive cycles of reading by the reader, by blowing air under high pressure through the lines in the reverse direction to the direction air travels when the reader is reading. Reading is blocked during the purging cycle by locking diaphragms in the interface.

Description

D United States Patent 1 1 1111 3,735,7'7i Panissidi 51 May 29, 1973 PNEUMATIC READER FOR [56] References Cited PERFORATED MEDIA UNITED STATES PATENTS 5 paniss'di Peeksk'll 1,274,103 7/1918 Story ..137 240 [73] Assignee: International Business Machines 2,827,767 3/1958 Hill ..91/36 Corporation, Armonk, N .Y.

I Primary Exammer-Martm P. Schwadron Flledi 1970 Assistant Examiner-Richard Gerard [2].] AppL NO; 103,223 Attorneyl-lanifin and Jancin Related us. Application Data 1 ABSTRACT [63] Continuation-impart of Ser. No. 824,424, May l4, A 'j perforated tape intermittent 1969 reader 1s connected to a pneumat1c-to-hydraul1c interface in a hydraulic control system. A hydraulically controlled pneumatic purge system is provided for [52] US. Cl. .137/15, 137/239, 137/624.l8, ejecting or purging foreign matter from the pneumatic Y I 235/201 FS reading lines between successive cycles of reading by I Int- Cl..... .i ..G06k the reader blowing air under pressure through Field of Search the lines in the reverse direction to the direction air travels when the reader is reading. Reading is blocked during the purging cycle by locking diaphragms in the interface.

9 Claims, 5 Drawing Figures SENSE 1501111111; VALVE P PURSE CONTROLVALVE PATENIEL Z HH 3,735,771

SHEET 1 OF 5 FIG. 1

8CHANNEL TAPE R PILOT CONTROL VALVE 22o HYDRAULIC 242 T SIGNAL T0 PILOT VALVE DIAPHRAGM?) 224 PURGE CONTROLVAILVE IINVENTOR 227 226 HUG0 A.PAN|SSIDII B M 1W ATTORNEY PATENIEL, HAY 2 91875 SHEET 3 BF 5 PATENIE 7.7291975 SHEET S BF 5 FIG. 20

1 PNEUMATIC READER FOR PERFORATED MEDIA CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of U. S. Pat.

.application Ser. No. 824,424' by H. A. Panissidi enti- BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to fluid sensing means for sensing the presence of indicia in the form of apertures in a record bearing medium and more particularly to means for ejecting foreign material from the sensing .means.

2. Description of the Prior Art In the'prior art means have been provided for preventing foreign material from entering perforated record pneumatic readers.

One such means includes a fluid jet stream from a first source generated on one side of a record card, etc., which passes through an aperture or perforation in it to provide a jet stream of air to be directed towards an orifice on the opposite side of the card. Connected to the orifice is a chamber continuously supplied with clean air from a second source so that the static pressure in the chamber varies as a function of the velocity of fluid flow through the orifice. A fluid pressure sensor is also connected to a chamber. Sufficient space must be maintained at all times between the orifice housing and the record card for flow of the clean fluid even when an imperforate record card surface is positioned between the jet stream and the orifice. This provides for continuous purging of contamination in the chamber. When the jet stream impinges on the orifice, the pressure differential is measured by the sensor. Problems associated with this approach are that the orifices will tend to become clogged with oil and lint if no filter is used. If a filter were used in a-factory environment, it would need to be cleaned very frequently and would have to be very elaborate to handle the kinds of contaminants present in a factory as opposed to a normal data processing environment.

The prior art has not shown meansfor using positive pressure single direction pneumatic reading combined with positive pressure ejection of contaminants in the reverse direction.

SUMMARY OF THE INVENTION An object of this invention is to provide means for purging contaminants from a pneumatic reader for aperture coded media.

Another object of this invention is to'provide a positive pressure reader for sensing air pressure passing through aperture coded media wherein the reader operates independently and intermittently.

Still another object is a purging system for such a reader wherein cross talk through the purging circuit is eliminated during the reading cycle.

Yet another object of this invention is to release purging pressure in the pneumatic circuit in a reader beforebeginning a reading cycle.

Another object'of this invention is to prevent reading of pulse data during pneumatic conduit purging cycles in a reader.

A further object is to clean the tape prior to reading the perforations therein while transferring its position on a reader.

Still another object is to eliminate the use of filters in a pneumatic reader for perforated media.

In accordance with this invention, a pneumatic reader for perforated media is provided in which an intermittent or periodic pneumatic purging cycle is employed to eject foreign matter by employing a reverse flow of air through the reader input lines between reading cycles.

Preferably sensors in the reader are disabled when the purging operation is being undertaken.

Further,'in accordance with this invention, cross talk is suppressed by mechanical means during reading. In another aspect, means are provided for releasing pressure in the system prior to reading after purging the system.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a simple embodiment of a pneumatic tape reader and air to hydraulic interface system in which an intermittent pneumatic purging system is employed.

FIG. 2 shows the arrangement of FIGS. 2A-2D which show an overall pneumatic and hydraulic system of the kind shown in FIG. 1 including a few modifications.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Reference is now made to FIG. 1 which shows an embodiment of the present invention which is illustrative with 16 ports to read perforated tape codes representing characters from a plastic tape 11. The 16 ports of the air reader head 10 are connected by sense hoses 12 to 16 diaphragms 102 driving hydraulic pilot valves 13 only one of which is shown in FIG. 1. The air reader head 10, supporting the tape 11, is pressurized with 10 psig air pressure by a spring loaded air manifold 111. A hole in the tape 11 will allow its corresponding diaphragm actuated pilot valve 13 to be pressurized with 10 psig air pressure from the air manifold.

The tape 11 is driven by a sprocket wheel 118 engaging drive holes in the tape 11. The sprocket 118 is attached to the shaft of the drive gear 121. The angular position of the drive gear 121 is accurately maintained by a spring loaded detent 124. When a hydraulic signal is applied on line 242 to the right end of control valve 220, control valve 220 moves to the left against the re- 3 action Qfitsspring 22] allowing the pressure manifold port P 222 to be exposed to line 76, thus applying hydraulic pressure to the end of land 136 of toggle valve 77, to move valve 77 to the right against the reaction of its spring 138 causing the toggle lever 126 to rotate counterclockwise to a vertical position. The pin 128 attached to the toggle lever and contacting the lower surface or rack 125 will raise rack 125 to cause the rack 125 to engage the drive gear 121, while flexing its drive wire 129. The toggle valve 77, which has been driven to the right as described earlier, will expose its port 139 to port P 116 applying hydraulic pressure to the left hand side of the drive piston 130 causing it to move to the right against the reaction of its spring 132 and rotating the drive gear 121 and sprocket wheel 118 counterclockwise advancing the tape 11.

With the hydraulic signal pressure on line 242 removed from the right hand side of the control valve 220, the control valve 220 will return to its initial posi- 1 tion by the reaction of its spring 221 exposing the port I 76 to R or a low pressure return line to the reservoir.

With pressure removed from the left hand 136 of the toggle valve 77, its spring 138 will drive it to the left rotating the toggle lever 126 to its initial position. The

toggle valve 77 will expose port 139 to its port R, thereby removing pressure-from the left hand side of the drive piston 130'allowing it and its rack 125 to return to its initial position by the reaction of its spring 132.

During the above tape advancing cycle, the pilot valve 13 of the hydraulic system must be physically locked by pressure on line 276 from responding to the tape holes as they move over the air reader head, and at the same time, the sense hoses, the diaphragms 102 and air reader ports 12 must be flushed out with a reverse air blast to purge the pneumatic sensing system of any contamination introduced during the previous reading cycle. With a hydraulic signal applied to the right handend of the control valve on line 242, it will move to the left against the reaction of its spring 221 exposing line 76 to its pressure port P 222 applying pressure to the left end of the toggle valve 77 affecting the tape drive as described earlier. Simultaneously it applies pressure on line 276 to the left end 85 of all the pilot valves 13 of the hydraulic system, preventing them from moving during the tape advancing period.

At the same time, line 76 is connected to the

left ends

96 and 96 of the purge control valve 99 and isolating valve 98 respectively causing both valves to move to the right against the reaction of their

respective springs

223 and 108. The transfer of the multiple land isolating valve 98 will expose all of the purge hoses 101 to the Ppo'rt 225 of the transferred purge control valve 99 via lines 235, and the cylinder 236 carrying valve 99. At the same time, it shuts off the air pressure to the air manifold by the scissoring action between line 110 and source 109 by the extreme right hand land 224 of the isolating valve 99.

Because the P port 225 of the purge control valve 99 is connected to a ten psig air pressure source, it provides a high velocity reverse air flow through the sixteen diaphragm chambers 102, sense hoses l2 and the air reader head ports. Thus, any foreign matter, is expelled between the air reader head 10 and tape 11 to the atmosphere. For purging of foreign material from sense lines 12, air under pressure is driven up through line 101 from isolating valve 98 through the input chambers of valves 102 to blow air in reverse up through the line 12 and under or through the tape 11 which is held down by manifold l 1 1 which is positioned by spring 117. Foreign matter is expelled between the tape and the members of air reader 10 as the air escapes. The spring is strong enough to hold the paper down. The spring is sufficiently weak to permit air carrying foreign matter to escape between the tape 11 and the parts of the reader 10. Following the purge cycle, the entire reading circuit and diaphragms 102 must be depressurized before releasing the locked diaphragm actuated pilot valves 13. In order to accomplish the depressurization, the purge control valve 99 must be returned to its initial left hand position before the return of the isolating valve 98 sealing off all the purge hoses 101.

A time delay network consisting of an orifice 228 in series with a delay piston 226 in cylinder 227 (connected to return 240 of valve 220 by line 241 at one end) is introduced to the right hand end of the purge control valve 99. Although both ends of the purge control valve 99 are exposed to line 76, the pressure buildup or rise is delayed on the right hand end 239 of the purge control valve 99 until the delay piston 226 has moved to the left with a time constant dependent upon cylinder length, its diameter and the size of the orifice 228. When the delay piston 226 has traveled its predetermined distance, the pressure at both ends of the purge control valve 99 will be equal, therefore allowing the reaction of the spring 223 to return the purge control valve 99 to its initial position to expose all the purge hoses 101 to the atmosphere through pneumatic return port R 229. Again, at the end of the tape advance cycle, the control valve 220 will be restored to its initial position by the reaction of its spring 221 with the removal of the hydraulic signal on line 242 exposing line 76 to the low, reservoir, hydraulic pressure. This allows the tape advance circuit, and the isolating valve 98 to reset to'their initial positions. It releases the locking pressure from the left hand ends of the pilot valves 13. I

Resetting of the isolating valve 98 admits air pressure from source 109 into the air manifold 111 and, at the same time, seals the individual purge hoses 10 to prevent cross talk between diaphragms 101 during the reading cycle as with the several diaphragms 101 which are shown in FIGS. 2A-2D. With the release of the locking pressure on line 276 from the pilot valves 13, the diaphragms 102 can respond to a hole in the tape 11 causing the transfer of the associated pilot valve 13 against the reaction of its spring 230. Thus,- data in the form of holes perforated on a tape controls the pilot valves 13 in a hydraulic system.

Lands

96, 231, 96', 234, 237 and 239, as well as 0 rings 230, 233 and 238 provide separation of the hydraulic and pneumatic systems.

Vents

232, 234 and 199 assure protection against pressurized air passing into the hydraulic system.

CONTROL SYSTEM Reference is now made to the control system shown in FIGS. 2A-2D which is shown and described in greater detail in my copending U. S. application Ser. No. 824,424. The system includes an air reader 10 for reading a perforated tape 11 which provides output pulses to a hydraulic control system by means of air lines 12 (FIG. 2C) connected to air hydraulic internected via

lines

141, 142 to extend or retract a corresponding one of piston adders which comprise interconnected pistons and cylinders employed to provide V binary displacement of load bearing shaft 156 by unit distances. 1

A set of variable orifices in a velocity control valve (not shown but connected to line 94) are provided between lines 142 and 342 for the purpose of controlling the rate of displacement of the pistons.

In order that the pistonadders and an output shaft connected to one end thereof may be accurately located rapidly, a damper, shown in my copending application is provided which permits the piston adders to cock itduring an exchange interval.

The exchange interval is a time during which the output shaft is firmly retained in position by braking means shown in part in FIG. 4 of my U. S. application Ser. No. 824,424 and in detail in my copending U. S. application Ser. No. 694,941 entitled Manipulator and the piston adders are reset and extended to the extent that certain pistons are retracted and certain other pistons are-extended. During the exchange period the velocity control valve will be held wide open to permit exchange at maximum permissable velocity, since the piston adders will not be under load. The flow system 23 includes

restrictive passageways

42, 44, 49 and orifices 50 and restrictive bypass valve 41 for varying the resistance of flow of fluid through line 52 and latch valves 14 and

lines

141 and 142 of the hydraulic circuit to the piston adder drive. A hydraulic logic unit responds to an output of system 23 on line to close valve 40 to increase the resistance to flow through system 23 to the piston adder drive and to release braking means controlled by aligner lines shown in Ser. No. 824,424. Exchange piston 35 and move piston 36 biased by springs 43 respond to decline of flow velocity below a predetermined level to cause

lines

24 and 25 to sense such decline by disconnecting those lines from a zero pressure return line 46. The move piston operates with line 24 for sensing the termination of a step of operation of the arithmetic piston adder drive.

In order to provide regulated hydraulic pressure to the system in my copending application Ser. No.

. 824,424, a hydraulic power supply is provided. It

supplies hydraulic pressure for latching of spool valves on

lines

600 and 116 and to the central lands 16 of spool valves in the hydraulic logic unit 20 via line 116. Pressure-is also supplied to the flow sensing system 23, via line 47, which controls two

bleed lines

24 and 25 to the hydraulic logic unit 20. The flow sensing system 23 operates as a function of the velocity of flow through line 47, the flow sensing system 23 and line 52 to the latch valves 14 which connect to the piston adders. When the flow or displacement of piston adders declines below a minimum value the bleed lines 24 and 25 are blocked by flow sensing system 23. A bypass control line 38 from the hydraulic logic unit 20 controls a

port

40, 41 inside the flow sensing system 23 to control one of the flow sensing units therein.

The hydraulic logic unit 20 can be started and stopped. Since the logic unit 20 controls the toggle line 76 in FIG. 2A which powers the feed advance of the tape reader shown in my copending application Ser. No. 824,424 when switch 54 is operated, air is blocked from operating the logic unit 20 and, at the end of a displacement cycle operation of the system stops. Line 94 adapted to connect to operate aligners not shown, which are similar to those shown in my copending United States patent application Ser. No. 694,941.

A set of sweep sense units 33 and a sweep cylinder 34 turn or sweep a load on support about an axis upon an input via line 198 or 200 from one of the latch valves 14. The sweep sense unit 33 is connected to bleed line 25.

EXCHANGE AND VARIABLE VELOCITY CONTROL The exchange and move flow sensing system 23 includes a cylindrical exchange sense piston valve 35, a cylindrical exchange move sense set valve 36 and a by pass poppet 37. The bypass poppet 37 is controlled by pressure in a line 38 connected to the lower output of flow spool valve 39 in FIG. 2B. When pressure in line 38 is above return pressure, it drives piston 37 to the right to open valve 40 by moving it away from surface 41. When there is no pressure in line 38, which results when line 38 is connected to a zero pressure return line, as via groove 95, when valve 39 is down, then piston 37 moves left closing valve 40.

When the bypass poppet 37 is to the left, its valve 40 will seat on surface 41 to close off the inlet 42 to the exchange sense piston 35. It should be noted that the exchange sense piston 35 and the move sense piston 36 are each spring biased by springs 43, coaxial therewith in the larger coaxial bore 44 in the

pistons

35 and 36. The

pistons

35 and 36 have annular grooves 45 to connect the bleed lines 24 and 25 to the return 46 to the low pressure side of the hydraulic pressure supply 22.

When piston 35 blocks bleed line 25 from return 46, as the result of a low flow rate through orifice 50 of piston 35, then after a time delay hydraulic logic 20 removes pressure from line 38, by driving flow spool valve 39 down which pulls piston 37 left to close valve 40- on surface 41.- Valve 39 connects line 38 to zero pressure, i.e., return pressure via groove 95. Pressure from a hydraulic pressure supply shown in Ser. No. 824,424 is supplied by line 47 to the inlet 48 on the upstream end of the valve 40 of the bypass poppet 37 which mayor may not be open, as described above, and to the inlet 49 to the move sense piston 36.

Hydraulic line 47 is connected to hydraulic line 52 through system 23 via inlet 48, which connects via inlet 49, orifice 50, coaxial bore 44, and line 51 connected to line 52, and in parallel, when valve 40 is open, through inlet 48, through port 41, past valve 40, through inlet 42, through orifice 50, through coaxial bore 44, and through line 51 to line 52 also. Each of the exchange sense piston 35 and the move sense piston 36 is provided with a smaller axial bore 50 to the upstream end thereof confronting the

corresponding inlet

42 or 49 thereof. The orifices 50 are selected so that when the pressure differential across the orifice 50 is above a predetermined level, then the pistons will be driven upwardly against the pressure of the springs 43 to align the grooves 45 with the bleed lines 24 and 25, thereby connecting the bleed lines to return 46. The bypass poppet 37 provides a means for selectively actuating the exchange sense piston 35. In this way, the flow sensing system may be operated in two modes depending on whether the piston adders are being driven in the move or exchange mode of operation.

A further feature is that each orifice 50 is of the same order of magnitude in diameter and length, so the resistance to fluid flow provided by each thereof is of the same order of magnitude. When both are connected in parallel, the resistance to flow provided by each thereof is of the same order of magnitude. When both are connected in parallel, the resistance to flow is nearly halved, or conversely, flow doubles, approximately. As will be noted, the outlets 51 of the two sense pistons are connected to line 52. Since the two sense pistons are in parallel, and therefore the orifices 50 are in parallel, if the bypass valve 40 is open, the quantity of flow through each of the two orifices 50 will be substantially equal and accordingly the rate of flow into the line 52, if sufficiently large and unrestricted will in general be approximately doubled. Accordingly, when the exchange sense piston 35 is permitted to operate by the bypass poppet 37, the-quantity of fluid flowing from lines 51 through line 52 to the piston adder drive will be greater and the velocity of displacement in the exchange period will accordingly be far greater.

HYDRAULIC LOGIC UNIT The hydraulic logic unit contains many types of elements. These include a plurality of spool valves, delay pistons in cylinders which require a time delay for displace-ment from one end to the other end of the cylinder in which they are housed, orifice check units shown in FIG. 2L of my copending application Ser. No. 824,424, interconnections and outlets which control other elements of the overall system. Certain spool valves are spring-biased into one position as indicated by helical springs in longitudinal cross section, Certain other of the spool valves are latch valves which areheld in position by hydraulic latching means. Such a latching means comprises a passageway 600 tangential to one end of a land of a spool located so that it supplies fluid under pressure to the side of the land regardless of spool position, and contacts a small area on one side. The land thereby creates a laminar pressure gradient along that side which is coupled to the return lines through leakage. There is a ratio of pressures across the land of several times the pressure on the low pressure side which pushes the land to one side and inhibits longitudinal sliding because of friction forces. Pressure can be relieved during movement of the spools to relieve friction forces.

When pressure at inlet 53 coupled from the tape reader actuated by start apertures 28 in the tape 11 via line 29, it operates the start diaphragm 56 (assuming pneumatic toggle 54 is on) or otherwise provides input from a two way solenoid or valve 27, etc. then the start spool valve 55 moves up. This movement connects its lines 57 to the right and to the left to higher pressure from the central annular groove 16 of valve 55 as the central land or ring passesthereabove. Pressure is applied at the junction 58 between the orifice checks (see FIG. 2B) 59 and 60 which connect to the probe spool valve 61, the probe delay piston 62, and the probe phase piston 63.

On the left side, the line 57 connects to the point 64 v to supply the lower end of flow spool valve 39; and by connection through orifice check 65, point 64 connects to line 66 and phase piston 67. Note that orifice check 65 is located differently from orifice check 70.

It will be noted that line 66 connects to bleed line 25 and both connect to the upper end of the flow spool valve 39, which is spring-biased down. However, pressure at point 64 biases the valve 39 up until line 66 is pressurized. When the flow phase piston 67 has moved fully to the top of its cylinder at the end of 60 milliseconds, and when exchange sense piston valve 35 disconnects bleed line 25 from return 46, the pressure on the line 25, and at the top of flow valve 39 increases and the flow valve 39 is pushed down hard to return to its position as shown in FIG. 2B under the force of the spring 87. The time delay is set by the orifice and piston 67.

Initially, after start valve 55 operates, flow valve 39 operates and pressure is placed on line 38. Then line 38 connects pressure to the bypass poppet 37, which remains open until the flow valve 39 returns to home position. Since line 38 is connected to the lower end of delay piston 68 and to the lower end of move spool valve 69, which is biased upwardly, the move valve 69 moves up fast shortly after the flow valve 39 moves up, by spring 53.

Later, when flow reverses, the delay piston 68 cooperates with the orifice check 70 to provide a long time delay before the move valve 69 can be reset down against the force of its spring 53. When the move valve 69 is driven up, the line 71 from the upper end of valve 69 has the pressure thereon released, thereby releasing pressure on the top of the exchange valve 72. Valve 72 has pressure on the lower end thereof applied on line 38. After the

delay valves

68 and 105 permit the pressure to build, valve 72 will then shift upwardly. The damp spool valve 73 has a spring bias at the lower end thereof, and will shift shortly after the exchange valve 72 shifts, thus releasing the pressure from its upper end. Line 75 is connected to the damper including its pistons secured to one end of the piston adders. Then in each displacement cycle of the drive, pressure is released from the damper positioning pistons. The damper is released to be cocked during exchange.

After about 20 milliseconds to position pilot valves 85, the probe delay piston 62 reaches the opposite end of its cylinder. Then the pressure on the lower end of probe spool valve 61 reaches a high enough level to overcome the spring biasing force at its top to drive the valve 61 to provide pressure on probe line 81 from the central annular pressure source 82 as the central land passes thereacross and the lower land passes across the return 83.

The probe line 81 is connected to probe of the inlets 84 of the pilot valves 85 to provide pressure to their central annular cavities. The probe pressure is employed to adjust the hydraulic binary latch valves 14 in accordance with the binary valves provided by the air, tape reader 10. The binary drive is reset by the most recent input data provided by the tape reader 10.

About 40 milliseconds after start, probe phase piston 63 rises to the top of its cylinder and causes a pressure build up at its lower end, connected to the top of probe spool valve 61 which is spring-biased down. Since the pressures of the opposite ends of the probe spool valve 61 will be equal and opposite, the probe valve is moved down by its spring 86. Then pressure is removed from probe line 81. This does not end the exchange motion of the piston adders which are controlled by hydraulic latch valves 14 which remain as positioned during the probe portion of the control cycle of the hydraulic logic circuit 20. While exchange continues, the exchange sense piston valve 35 remains against it spring like move sense piston valve 36.

'When exchange velocity substantially ends resulting in elimination of substantial pressure differential the flow through the

sense pistons

35 and 36 ends, substantially, they move down to their spring biased lower positions. Then bleed line 24 closes momentarily and bleed line 25 closes for the remainder of each cycle of operation of the hydraulic logic unit 20. Line 25 then builds up pressure on the upper end of the flow valve 39 and its top spring 87 pushes flow valve 39 down..

Pressure builds on line 24 and line 89 from

lines

16 and 688 through the flow valve 39. However, the delay piston 68 and the orifice 703 in orifice check 70 defers the build up of the pressure in the lines 24 and the build up of the pressure in inlet 89 to a level sufficient to push move valve 69 down. Move valve 69 will not operate after exchange because move sense piston 36 reconnects bleed line 24 to return 46 to bleed pressure from inlet 89 before sufficient time passes to build up enough pressure in inlet 89. Line 688 applies pressure immediately to the central cylindrical cavity 188 of the exchange spoolvalve'72 held up by pressure in line 38 to provide pressure on line 90 to the lower end of the aligner latch valve 74. Low pressure on line 75 and high pressure on line 90 drives the aligner latch valve 74 up.

The aligner lat'ch valve 74 releases pressure on line 91 so spring 93 drives aligner valve 92 up. This applies pressure to line 189 resetting start valve 55, applying pressure from line 116 to reset line 88 to reset all of the pilot valves 85 and will release pressure from line 94 which is to be connected to load aligners to move the output load. Line 94 also connects to the velocity control valve 17 to move it to reduce the orifice into the piston adders 15 during the period of driving of the load. Now the load can move so the piston adders can move and flow resumes in line 52. Thus the pressure drop across the move sense piston valve 36 resumes and move sense piston valve 36 moves up again to bleed pressure from the bleed line 24.

Pressure on the control line 38 for bypass poppet 37 is released since theflow valve 39 is down to connect line 38 to the return 95. Pressure on line 76 connected to reader from aligner latch valve 74 in FIG. 2A is intended to operate the tape reader feed mechanism. In

' addition, in a purge control shown in my copending application Ser. No. 824,424 pressure in line 76, will operate a pair of pistons 96 from line 97 attached to the line 76 to drive the

spool valves

98 and 99 to the left so that the pressure on line 100 will be connected down into the lines 101 which are connected to the purge inlets to the diaphragms 102 in the air hydraulic interfaces 13 in, FIG. 2C. Air under 10 psig pressure blows through the purge inlets 10] across the surface of the diaphragms of the interfaces 102 and out through the reader lines 12 to purge or to drive oil from the system and to clear chad and other material from the

lines

12 and 1 12.

Pressure remains on line 76 until the piston adders stop and move valve 69 moves when bleed line 24 closes as move sense piston 36 moves down. Then, line 71 drives exchange valve 72 down removing pressure from line 90 and applying pressure to line 103 through 10 the orifice of orifice check 104 and delay piston 105, after a'time delay of milliseconds, which pressure drives the damp valve 73 down against its spring. Valve 73 applies pressure on line 75 to drive the aligner latch valve 74 down and remove pressure from line '76 and to apply pressure to line 91 and through the orifice in the orifice check 106 and delay piston 107 require a time delay to pass before pressure drives aligner valve 92 down against its spring 93. The aligner delay piston 107 requires another 120 milliseconds to drive downwardly.

However, referring again to the purge unit, when line 71 is pressurized, a piston 99 is shifted right so atmospheric pressure from line 99, to atmosphere will be permitted to resume inside the purge and

reader lines

101 and 12 to return diaphragms 102 to atmospheric pressure. Then when pressure is removed from line 76 as a result of return of the aligner latch valve 74 to its lower position, the spring 108 of the spool valve 98 will act to drive that spool valve to the right and to shut off connections 101 to the diaphragms. It should be noted that the 10 psig air supply 109 is connected to line 1 10 which applies positive pressure to the air pressure head 111 for passage through the tape 11 into the inlets 12 to the diaphragms 102.

During the time that the purge spool valve 98 is to the left, the blocking of pressure by valve 98 from line 110 to the air reader 1 11 will prevent blowing air down into the diaphragms 102 during the purge cycle when air is to be blown in the reverse direction.

The perforated tape reader shown in FIG. 2 will operate in ordinary machine shop air typical of industrial locations, which is contaminated with dirt, oil and water. Cyclic purging of lines 12 is necessary because the reader sense hoses are extremely thin, usually 0.030 inches I.D. making them vulnerable to clogging.

In order to avoid costly memory devices and serial to parallel converters for some applications, the reader is designed to advance the tape up to two characters per step, allowing the system to accept two characters of data simultaneously. The hydraulically driven reader, as shown schematically, consists of an air reader head with 16 ports to accept two perforated characters of an 8 channel Mylar tape. The 16 ports of the air reader head are connected by sense hoses to the 16 diaphragm driven hydraulic pilot valves. The air reader head, supporting the tape, is pressurized with 10 psig air by a spring loaded air manifold. A hole in the tape pres surizes its corresponding diaphragm actuated pilot valve with 10 psig from the air manifold.

The air reader 10 includes an air pressure head 111 which is spring biased downwardly by a spring 1 17. The tape which is used includes eight longitudinal columns and is read in groups of two rows of characters such, as shown in FIG. 2D, simultaneously. Accordingly, the feed must advance two rows of holes for each reading cycle. The top hole in the first row is the start control. The next two holes are M2 and M1 controls for FIG. 2E and the next holes ones are the fractions from onehalf inch down to one thirty-second inch. In the second column in the second hole, the sweep mode of operation of the manipulator which would be attached to the device is entered and in the third hole, the bit for the grip mode of operation of a manipulator gripper would be entered. In the last five holes in the second column, the bits forthe 16, 8, 4, 2 and 1 inch piston adders would be entered. The head 111 is designed so as to I provide air pressure above all 16 holes and underneath the holes would be aligned the various inlets 12 to the diaphragms 102 shown in FIG. 2D.

The feeding mechanism is comprised of a sprocket wheel 118 which operates in cooperation with perforations 119 in the tape 11. The sprocket wheel 118 is secured to shaft 120 and the shaft 120 is journalled for rotation in response to torque applied by' gear 121 which is retained in position by detent pawl 122 which is spring-biased downwardly by spring 123. The pawl 122 carries a pin 124 at one end thereof which fits into the teeth of gear 121. v

The gear 121 is adapted to mesh with a rack 125 which can be raised into gear by a toggle lever 126 which is pivotally secured by pin 127 in which toggle lever carries rack 125 on pin 128. The rack 125 is reciprocably longitudinally slideable on drive wire 129 secured at its distal end to a piston 130 slideably carried in cylinder 131 for longitudinal reciprocation therein.

The cylinder 13] contains a spring 132 at the distal end of the piston 130 for biasing the piston 130 leftwardly. At the opposite end of the cylinder is a release aperture 333 to permit motion to the right. The opposite end of the toggle lever 126 is secured to a drive wire 133 by means of pin 134 to bifurcated end 135 of drive 'wire 133. Drive wire 133 is secured at its distal end to a spool valve 136 carried in cylinder 137.

The spool valve 136 is spring-biased leftwardly by spring 138. At the leftward end of piston 130 is an inlet 139 connected from the central portion of cylinder 137 adapted forcommunication with the two inlets 81 and 281 into the lower cylinder 137 from the central portion thereof.

At the leftward extreme end of cylinder 137 is located an inlet from line 76. Line 76 from the aligner latch valve lower outlet is provided for starting operation of each cycle of the"reader. If pressure were applied to line 76, it would function to pull the toggle level 126 counterclockwise about pin 127 by means of flexing of drive wire 133. Lever 126 and pin 128 will drive the rack 125 up into engagement with the gear 121 preparatory to actual driving motion. When this occurs, i.e., valve 77 is to the right, the connection of line 139 to the cylinder 137 will be made to the line 116. This will drive the piston 130 to the right against the reaction of its spring 132 pulling wire 129 and the rack 125 to the right and turning the gear 121 counterclockwise about shaft 120 thereby advancing the tape 11 two character positions to the left as the sprocket 118 is turned on the shaft 120 counterclockwise.

While probe pressure drives the air reader, such probing does not occur until after the pressure on the purge line 76 has been generated by means of driving the aligner latch valve 74 to its upper position after the exchange is terminated. The adjustment of the pilot valves during the probe cycle will have been completed .well prior to that time; and with the application of pressure on line 76, and the displacement of the purge spool valve 98 to the left, the pressure applied on line 1 to the air pressure head 1 1 1 will have been blocked by the leftward land of the spool valve 98. This turns off pressure to the reader head 111.

During the period the rack rotates the drive gear, there is a substantial separating force between the rack and gear due to the pressure angle of the gear teeth (20) which is supported by the toggle shaft.

With pressure removed from the left end of the toggle valve, its spring will drive it to the left rotating the toggle lever 126 to its initial position. The toggle valve will expose port 139 to its port 281, thereby removing pressure from the left-hand side of the drive piston allowing it and its rack to return to its initial position by the reaction of its spring.

During a tape advance cycle described in the above application, the pilot valves of the hydraulic system must be physically locked by pressure in line 88 from responding to the tape holes 28 as they move under the air reader head 111, and at the same time sense hoses l2, diaphragms 102 and air reader ports must be flushed out with a reverse air blast to purge the air sense system of any contamination from the previous read cycle. Line 76 to the purge control and isolating valves 98, respectively, causes both valves to move to the left, valve 98 moving against the reaction of its spring 108. The transfer of the multiple land isolating valve 98 will expose all of the purge lines 101 to pressure port of the transferred purge control valve 99 and, at the same time, shut off the air pressure to the air manifold 1 10 by the scissoring action of the extreme left-hand land of the isolating valve 98.

The port 100 of the purge control valve exposed to its 10 psig port 109 provides a reverse air flow pressure. The pressure blows air in reverse through the diaphragm chambers, sense hoses and the air reader head ports. Foreign matter if any is expelled between the air reader head and tape to the atmosphere. Following this purge cycle, the entire reading circuit and diaphragms must be depressurized before releasing the locked diaphragm actuated pilot valves. To accomplish depressurization, the purge control valve is returned to its initial position before the return of the isolating valve 98 seals off all the purge hoses 101.

A time delay network consisting of an orifice in series with move delay piston 68 controls return of the purge control valve 99 to its initial position to expose all the purge hoses to the atmosphere through port 281. Again at the end of the tape advance cycle the aligner latch valve 74 is restored to its initial position with the removal of the hydraulic signal, exposing line 76 to the reservoir allowing the tape advance circuit and isolating valve to reset to their initial positions.

The reset of the isolating valve will admit air pressure to the air manifold and, at the same time, seal the individual purge hoses to prevent cross talk. With the release of the locking pressure from the pilot valves, it

will allow the diaphragms to respond to a hole in the tape causing the transfer of the pilot valve against the reaction of its spring.

An advantage of the above described pneumatic tape reader is that it has a minimal number of moving parts, is capable of reading two characters simultaneously,

and in contrast with the type of reader which had been required in connection with this type of system before, eliminates the need for a character buffer storage unit. Use of pressure instead of vacuum sensing of the tape holes minimizes the problem of contamination and costly filtration. I

AIR HYDRAULIC INTERFACE From the lines 12 of the air reader 10 connection is made, as described above, to the lines 12 to the diaphragms 102 in FIG. 2C. When pressure is applied to a line 12, then one of the corresponding diaphragms 102 operates to drive its pilot valve 85 left. This drives the associated latch valve 14 left, during present of pressure on probe line 81, as the line 84 connects to the right-hand side of the central land of the pilot valve 85. Pressure is applied to the right end of latch valve 14. Latch valve 14-16 on the left-hand side of FIG. 2C. The numeral 14l6 indicates that the latch valve is connected to the 16 inch piston adder 140 by

lines

141 and 142. The right hand one of the lines 142 has pressure applied to it when the pilot valve is actuated by the reader. Line 142 passes through the velocity control valve, and pressure on line 94, reduces the orifice through the velocity control valve for the piston adders. Exchange occurs fast; as described below. First, the load is braked and in essence disconnected from the piston adders so no moving or collapsing of the heavy load occurs during exchange. Secondly, orifices regulate the rate of flow of fluid to the adder drive. Such regulation is afforded in two ways. First opening or closing of the bypass poppet 37 controls the effective orifice size to control flow. Second, a velocity control valve controls flow. The velocity control valve is controlled through line 94 from hydraulic logic 20.

What is claimed is:

1. An apparatus for reading perforated media including pneumatic sensing means,

pneumatic coupling means for coupling pneumatic signals between input terminals of said coupling means and said pneumatic sensing means,

the improvement comprising integral pneumatic purging means for providing periodic pneumatic purging cycles for purging fluid through said pneumatic coupling means in the reverse direction from said pneumatic input signals to eject foreign material from said means for coupling,

and control means for alternating said pneumatic purging cycles with pneumatic coupling cycles, said pneumatic coupling cyclescomprising intervals during which pneumatic input signals are coupled by said coupling means to said pneumatic sensing means.

2. Apparatus in accordance with claim 1 wherein said control means operates inhibiting valve means for preventing sensing by said pneumatic sensing means dur ing operation of said purging means.

3. Apparatus in according with claim 2 including terminating means for terminating purging by said purging means a predetermined period of time prior to termination of operation of said inhibiting valve means in order to prevent residual purging pressure from actuating said pneumatic sensing means.

4. Apparatus in accordance with claim 1 including a source of pneumatic reading fluid connected to an outlet directed at said input terminals of said pneumatic coupling means, and valving means for blocking said 7 source from said outlet during purging by said purging means.

5. Apparatus in accordance with claim 3 wherein said terminating means comprises a time delay circuit and a pressure control valve.

6. Apparatus in' according with claim .1 wherein said purging means includes means for blocking cross talk between separate pneumatic coupling means between pneumatic coupling cycles.

7. An air reader including a plurality of sensing lines,

a source of pneumatic pressure communicating with a pneumatic manifold spaced above the input ends of said sensing lines,

plurality of pneumatic diaphragms responsive to varying pressure in said sensing lines each having an input chamber and coupled to a means for sensing displacement of a said diaphragm from a predetermined position, each of said diaphragms being biased to a said predetermined position, a said sensing line connected to each said diaphragm input chamber, an isolating valve including a manifold having an outlet for fluid connection with each diaphragm input chamber, said valve including a land for closing each outlet in a blocking position of said valve,

means for biasing said isolating valve to said blocking position with a separate land arresting communication between said isolating valve manifold and each of said outlets from said valve,

each of said outlets being connected to an input chamber for a diaphragm,

a purging source of pneumatic fluid under pressure connected to said isolating valve manifold under control of said isolating valve for providing relatively high velocity air flow through said diaphragm input chambers and through said sensing lines to said input ends thereof and therethrough for purging therefrom foreign matter contained therein.

8. Apparatus in accordance with claim 7 including a purge control valve means and time delay means associated therewith connected between said purging source and said isolating valve for blocking purging flow -a predetermined time period after initiation of a cycle of purging flow.

9. A method for reading perforated media pneumatically including,

coupling pneumatic input signals to pneumatic sensing means through pneumatic coupling means,

the improvement comprising using integral pneumatic purging means for periodically purging fluid through said pneumatic coupling means in the reverse direction from the direction from which the pneumatic input signals are applied in order to eject foreign material from said pneumatic coupling means,

and using control means for alternating the pneumatic purging cycles with pneumatic coupling cycles, said pneumatic coupling cycles comprising intervals during which pneumatic input signals are cou pled by said coupling means to said pneumatic sensing means.

Claims

1. An apparatus for reading perforated media including pneumatic sensing means, pneumatic coupliNg means for coupling pneumatic signals between input terminals of said coupling means and said pneumatic sensing means, the improvement comprising integral pneumatic purging means for providing periodic pneumatic purging cycles for purging fluid through said pneumatic coupling means in the reverse direction from said pneumatic input signals to eject foreign material from said means for coupling, and control means for alternating said pneumatic purging cycles with pneumatic coupling cycles, said pneumatic coupling cycles comprising intervals during which pneumatic input signals are coupled by said coupling means to said pneumatic sensing means.

2. Apparatus in accordance with claim 1 wherein said control means operates inhibiting valve means for preventing sensing by said pneumatic sensing means during operation of said purging means.

4. Apparatus in accordance with claim 1 including a source of pneumatic reading fluid connected to an outlet directed at said input terminals of said pneumatic coupling means, and valving means for blocking said source from said outlet during purging by said purging means.

6. Apparatus in accordance with claim 1 wherein said purging means includes means for blocking cross talk between separate pneumatic coupling means between pneumatic coupling cycles.

7. An air reader including a plurality of sensing lines, a source of pneumatic pressure communicating with a pneumatic manifold spaced above the input ends of said sensing lines, a plurality of pneumatic diaphragms responsive to varying pressure in said sensing lines each having an input chamber and coupled to a means for sensing displacement of a said diaphragm from a predetermined position, each of said diaphragms being biased to a said predetermined position, a said sensing line connected to each said diaphragm input chamber, an isolating valve including a manifold having an outlet for fluid connection with each diaphragm input chamber, said valve including a land for closing each outlet in a blocking position of said valve, means for biasing said isolating valve to said blocking position with a separate land arresting communication between said isolating valve manifold and each of said outlets from said valve, each of said outlets being connected to an input chamber for a diaphragm, a purging source of pneumatic fluid under pressure connected to said isolating valve manifold under control of said isolating valve for providing relatively high velocity air flow through said diaphragm input chambers and through said sensing lines to said input ends thereof and therethrough for purging therefrom foreign matter contained therein.

8. Apparatus in accordance with claim 7 including a purge control valve means and time delay means associated therewith connected between said purging source and said isolating valve for blocking purging flow a predetermined time period after initiation of a cycle of purging flow.

9. A method for reading perforated media pneumatically including, coupling pneumatic input signals to pneumatic sensing means through pneumatic coupling means, the improvement comprising using integral pneumatic purging means for periodically purging fluid through said pneumatic coupling means in the reverse direction from the direction from which the pneumatic input signals are applied in order to eject foreign material from said pneumatic coupling means, and using control means for alternating the pneumatic purging cycles with pneumatic coupling cycles, said pneumatic coupling cycles comprising inTervals during which pneumatic input signals are coupled by said coupling means to said pneumatic sensing means.