US3796132A

US3796132A - Cocked damping mechanism

Info

Publication number: US3796132A
Application number: US00236520A
Authority: US
Inventors: H Panissidi
Original assignee: International Business Machines Corp
Current assignee: International Business Machines Corp
Priority date: 1969-05-14
Filing date: 1972-03-20
Publication date: 1974-03-12
Anticipated expiration: 1991-03-12

Abstract

A digital hydraulic system converts binary digital input information into displacement of a digital drive. An air reader is used to operate binary latch valves through an air hydraulic interface. A flow sensing system and a hydraulic logic unit cooperate to provide high speed exchange between the piston adders of the digital drive prior to displacement of the load. A hydraulic cylinder sweeps the load about a vertical axis. A selfcooling, air-driven hydraulic pump with an accumulator, provides relatively constant pressure. A damper secured to the piston adders has an additional drive for providing precise location at the end of damping. An incremental paper tape feed with a four motion rack with toggle action indexes the air reader.

Description

United States Patent Panissidi Mar. 12, 1974 COCKED DAMPING MECHANISM 75 Inventor: Hugo A. Panissidi, Peekskill, NY. f Geoghega Assistant ExammerAllen M. Ostrager [73] Assignee: International Business Machines A or Agent, or Firm Grah S. Jones, ll

Corporation, Armonk, NY. 22 Filed: Mar. 20, 1972 [571 1 ABSTRACT A digita hydraulic system converts binary digital input [211 App! 236520 information into displacement of a digital drive. An air Related US, Application D t reader is used to operate binary latch valves through [62] Division of Sen 824,424, May 14 1969 Pat NO. an air hydraulic interface. A flow sensing system and a hydraulic logic unit cooperate to provide high speed exchange between the piston adders of the digital 52 us. Cl. 91/167, 92/9 drivc prior to displacement of thc lcad- A hydraulic [51] I (1 15 1 1 cylinder sweeps the load about a vertical axis. A self- 58 Field of Search 92/8, 9, 10, 11; 91/167 cooling, air-driven hydraulic P p with an accumulator, provides relatively constant pressure. A damper 5 References Cited secured to the piston adders has an additional drive UNITED STATES PATENTS for providing precise location at the end of damping. 4 An incremental paper tape feed with a four motion E53 Z rack with toggle action indexes the air reader. 3,476,266 11/1969 Devoi 11 92/9 X 7 Claims, 17 Drawing Figures 114i ;l42 .;l4i [J42 EH I42 Ml M2 {98 /200 75 I47 155 Z i 1/2 /4 us me r200 PAIEIIIEIIIImIw afrssdaz SHEET '01 or 14 FIG. 1

TAPE I? 14 SWITCHING 15 I I" I4I,I42 HYDRAULIC I2 VELOCITY BINARY AIR AIR CONTROL LATCH HYDRAULIC VALVE VALVES |NTER|=ACE READER RESET 7 88 PROBE \OPERATE 542x I4I,I42 116 X TOGGLE H5 DRIVE RACK 16 EII FE 52 W To A QQ'JE HYDRAULIC N DAMPER FLOW POWER ADDERS 5 SENSING SUPPLY 156 j {8 81M SYSTEM 75 76/ MFA s? 5 -BLEED H6 CONTROL HYDRAULIC LOGIC START I i ON-OFF /94 DECODER I WITH ALIGNERS TREE |83 L51 25 52/ CLAMP 200 19a RACK BLEED I r I 53\ I 206 f SWEEP 196 54 S SENSE u SWEEP g \SWEEP km R SENSE T PAYENYEDAAA 12 1974 3; 796; 132

SHEET 12 F 14 FIG. FIG. F|G-3 3A 3B FIG. 3A

1 lsoLAnol vALvE o- DISPLACEMENT IN' INCHES PURGE CONTROL vALvEo- L0AD1"- VELOCITY CONTROL vALvE0- READER RACK PISTON0 READER TOGGLE vALvED- ALIGNER PISTON 0- ALIGNER. vALvEo- ALIGNER DELAY P|STON0 ALIGNER LATCH VALVE0- DAMPER PISTON o DAMPER DELAY P|STON0 DAMPER VALVE0- EXCHANGE mm 0- MOVE vALvE 0- MOVE SENSE vALvED- EXCHANGE SENSE VALVE0- BYPASS P0PPET(1 1" CYLINDER 0- o.1 LATCH VALVE0 2" CYLINDER-' N0.2 LATCH VALVE0 N0.2 PILOT vALvEo- MOVE DELAY P|STON0- FLOW VALVE 'o- FLOWVVALVE PISTON0 START VALVE o- PROBE VALVE 0- PROBE DELAY P|STON-0- PROBE PHASE P|$TON0- TIME IN MILLISECONDS PATENTEDHAR 12 I974 saw 13 OF 14 FIG. 3B

IlllIlllIlIlIlIlIIlIIIIIIIIIII TIME IN MILLISECONDS- skrssLma ISOLATION VALVE PURGE CONTROL VALVE LOAD VELOCITY CONTROL VALVE READER RACK PISTON READER TOCGLE VALVE ALIGNER PISTON ALICNER VALVE ALIGNER DELAY PISTON ALICNER LATCH VALVE DAMPER PISTON DAMPER DELAY PISTON DAMPER VALVE EXCHANGE VALVE MOVE VALVE MOVE SENSE VALVE EXCHANGE SENSE VALVE BYPASS POPPET I" CYLINDER NO. I LATCH VALVE 2" CYLINDER NO.2 LATCH VALVE NO.2 PILOT VALVE MOVE DELAY PISTON FLOW VALVE FLOW VALVE PISTON START VALVE PROBE VALVE PROBE DELAY PISTON PROBE PHASE PISTON PAIENTEDNAR 12 m4 3.796; 1132 saw u nr 14 COCKED DAMPING MECHANISM This is a division, of application Ser. No. 824,424 filed May 14, 1969 now U.S. Pat. 3,726,190.

CROSS REFERENCE TO RELATED APPLICATIONS This application is related to copending U.S. application Ser. No. 694,941 by I-I.A. Panissidi entitled Manipulator, U.S. Pat. No. 3,550,630 issued on application Ser. No. 695,139 by I-I.A. Panissidi entitled Serial-to-Parallel Hydraulic Device, and U.S. Pat. application Ser. No. 824,425 now U.S. Pat. No. 3,641,877 entitled Flow Sensing System and Valve by R. C. Hebert, filed herewith.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to damping devices. More particularly, this invention relates to damping devices which are secured to a digital drive mechanism.

2. Description of the Prior Art Conventional damping mechanism may contain springs or other means for returning the damper'to a zero or neutral position. However, previously known damping mechanisms in the art have not included any means for precisely locating the moveable mechanism relative to a fixed member. Accordingly, in connection with accurate digital drives, it is highly desirable to provide some means for providing damping and at the same time including control mechanism and means for precisely locating the load at the end of the displacement cycle.

Prior air driven engines have toggled relatively slowly thereby causing a fairly high degree of regulation or fluctuation in output pressure from the oil pump. Faster systems have often employed electrical motors which have created a significant heat dissipation problem. External cooling arrangements have been supplied for such systems including radiators, circulation of oil to the radiators on the exterior of the system. Such radiators require space and are costly.

location. In connection with digital drives, means are provided of accurately locating the first member of the digital drive relative to a zero position after each operation of the digital drive to displace the load in a predetermined direction has been accomplished. In another aspect, means are provided for initially cocking the damping mechanism into a position in the opposite direction from the final direction of displacement. Subsequently, upon deceleration by the damper with minimum overshoot, the load is caused to locate by positive locating means in the damper.

An object of this invention is to provide accurate location of a digital drive subsequent to the major displacement motion of that drive and damping thereof.

A further object of this invention is to provide means for efficient damping of a drive subsequent to displacement of the load.

A related object is to provide damping with minimum overshoot.

An object to this invention is to provide means for reversing the direction of operation of an air engine prior to the time that the pump being driven thereby reaches its extreme position.

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

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a schematic block diagram of the overall system employed in accordance with this invention.

FIG. 2 shows the relationship between the various sections of the large diagram of FIGS. 2A-2K. FIGS. 2A-2K show the overall connections between the various subsystems of the integrated adder drive assembly employed in accordance with this invention, and in FIGS. 2K and 2L additional details of the system are shown.

FIG. 3 shows the relationship between FIGS. 3A and 3B.

FIG. 3A and 3B show the displacement characteristics of valves and mechanism in the hydraulic system shown in FIGS. 1 and 2A-2K in accordance with this invention as a function of time.

FIG. 4 shows the sweep and arm clamping mechanisms for the base of a manipulators arm.

- DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT CONTROL SYSTEM Referring to FIG. 1, the present system includes an air reader 10 for reading a perforated tape 11 which provides output pulses to a hydraulic control system by means of an air line 12 and an air hydraulic interface 13 which converts pneumatic pulses to hydraulic values. The air hydraulic interface transfers pulse inputs to hydraulic binary latch valves 14 which remember or retain a O or a 1 condition, depending upon the sense or polarity of the input transmitted from reader 10 through the interface 13.

The outputsof the latch valves are in general connected via

lines

141, 142 to extend or retract a corresponding one of several piston adders 15 which comprise a series of interconnected pistons and cylinders employed to provide binary displacement of a load bearing shaft 156 by unit distances, in binary progression from from one thirty-second inch to almost 32 inches in binary steps up to 16 inches.

For the l, 2, 4, 8 and 16 inch long piston adders, a set of variable orifices in a velocity control valve 17 are provided between

lines

141, 142 and 342 for the purpose of controlling the rate of displacement of the pistons with larger displacements.

In order that the piston adders 15 and the output shaft 156 connected to one end thereof may be accurately located rapidly, a damper 18 is provided which permits the piston adders 15 to be cocked during an exchange interval.

The exchange interval is a time during which the output shaft 156 is firmly retained in position by braking or arresting means shown in part herein and shown in full in above U.S. Pat. No. 3,575,301 and the piston ad- 7 ders 15 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 17 will be held wide open to permit exchange at maximum permissable velocity, since the piston adders 15 will not be under load.

Referring again to the damper 18, when the load has provides hydraulic damping with minimum overshoot and is actuated via line 75 by hydraulic logic unit to provide mechanical positioning ultimately to a precise home position. Cocking minimizes overshoot and optimizes use of time for the steps of exchanging piston locations and driving the load.

In order to provide regulated hydraulic pressure to the system a hydraulic power supply 22 is provided. It supplies pressure for latching and to the central lands 16 of spool valves in the hydraulic logic unit via line 116 and the flow sensing system 23, via line 47, which controls two bleed lines 24 and to the hydraulic logic unit 20 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 15. 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.

. grooves 45 with the bleed lines 24 and 25, thereby con- The hydraulic logic unit 20 can be started and stopped. Since the logic unit 20 controls the toggle line 76 which powers the feed advance of the tape reader 10, when switch 54 is operated, air is blocked from op erating the logic unit 20 and at the end of a displacement cycle operation of the system stops.

As the drive is adapted to displace a plurality of members, a decoder is connected to the logic unit 20 via line 94, and to certain ones of the latch valves 14, to operate aligners 31 to hold the various members to be displaced by the output shaft, through a linkage, not shown, which is similar to that shown in copending U.S. Pat. No. 3,575,301. Clamp rack 33 is engaged when it is desired to drive the Z arm of the output, for example, a manipulator, as shown in FIG. 4.

A set of sweep sense units 33 and a sweep cylinder 34 are employed to sweep a load on support 190 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.

Referring to FIGS. 2A-2J, the overall system is shown in greater detail than in FIG. 1 and the connections between the various systems are shown.

EXCHANGE AND VARIABLE VELOCITY CONTROL The exchange and move flow sensing system 23 includes a cylindrical exchange sense piston 35, a cylindrical move sense piston 36 and a bypass 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 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 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 are grooved at 45 to connect the bleed lines 24 and 25 to the return 46 to the low pressure side of the hydraulic pressure supply 22. Pressure from the hydraulic pressure supply 22 is supplied by line 47 to the inlet 48 on the upstream end of the valve of the bypass poppet 37 which may or may not be open, as described above, and to the inlet 49 to the move sense piston 36. Each of the exchange sense piston 35 and the move sense piston 36 is provided with necting the bleed lines to return 46. The by-pass 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 15 are being driven in the move or exchange mode of operation. A further feature of this system is that since each of the orifices 50 is substantially of the same order of magnitude in diameter and length, the resistance to fluid flow provided by each thereof is substantially 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 46 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. (See U.S. Pat. No. 3,641,877 for a more complete description under this section).

HYDRAULIC LOGIC UNIT The hydraulic logic unit comprises a plurality of spool valves, delay pistons in cylinders which comprise compliance or capacitive units which require a time delay for displacement from one end to the other end of the cylinder in which they are housed; orifices, check units described below in connection with FIG. 2L, interconnections and outlets which control other elements of the overall system. Certain of the 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 are held 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 inlet side to 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 relievd during movement of the spools to relieve friction forces.

When the start diaphragm 56 is operated by the pressure at inlet 53 (assuming pneumatic toggle 54 is on) from the reader start apertures 28 in the tape via line 29, or otherwise provides input from a two way solenoid or valve 27, etc. then the start spool valve 55 is driven upwardly thereby connecting its lines 57 to the right and to the left to higher pressure from the central annular groove 16 as the central land or ring passes therabove. Accordingly, pressure will be applied at the junction 58 between the orifice checks (described below in connection with FIG. 2L, 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 is connected to the point 64 which supplies the lower end of flow spool valve 39; and by orifice check 65 point 64 is connected to line 66 and phase piston 67. It will be noted that line 66 is connected to bleed line 25 and both are connected to the upper end of the flow spool 39, valve which is spring biased downwardly. Accordingly, when the flow phase piston 67 has moved fully to the top of its cylinder at the end of 60 milliseconds, then as soon as the exchange sense valve causes the bleed line 25 to be disconnected from the return 46, the pressure on the line 25, and therefore on the upper end of the flow spool valve will be increased and the flow spool valve will be driven back to its position as shown in FIG. 2B by the force of the spring 87. Initially, then, as soon as the start valve is operated, the flow valve will be operated also and pressure will be placed upon line 38 from the central high pressure source and line 38 will connect pressure to the bypass poppet, which will remain open until the flow valve is driven back to its 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 will be driven rather rapidly upwardly shortly after the flow valve is driven upwardly, by the spring 53. It should be noted that later, when flow is reversed, the delay piston 68 cooperates with the orifice check 70 to provide a long time delay before it is possible for the move valve 69 to be reset down against the force of its spring 53. When the move valve is driven upwardly, the line 71 from the upper end thereof has the pressure thereon released, thereby releasing pressure on the upper end of the exchange spool valve 72 which will have pressure on the lower end thereof from the line 38 which, after the delay valves have permitted the pressure to build, 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 valves shifts, thus releasing the pressure from the uper end thereof. Line 75 is connected to the damper 18 including its pistons as shown in FIG. 1 and FIG. 2J secured to one end of the piston adders 15. At this point in each displacement cycle of the drive, pressure is released from the damper positioning pistons 80. Accordingly, the damper is released so that it can be cocked during the exchange mode of operation. After an interval of about milliseconds selected to allow pilot valves 85 to be positioned, according to the data in the tape, the probe delay piston 62 will have reached the opposite end of its cylinder. Accordingly,'the pressure at the lower end of the probe spool valve 61 will have reached a high enough level to overcome the spring biasing force at its upper end and to drive the valve upwardly thereby providing 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 each 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 reader 10. Thus, the

binary drive will be reset in accordance with the most recent input data provided thereto in the tape under the air reader 10. It will be understood that another variety of input source could be connected through a suitable interface. About 40 milliseconds after start, the probe phase piston 63 will rise to the top of its somewhat longer cylinder and at that time will cause a pressure build up at its lower end, which is connected to the upper end of the probe spool valve 61 which is spring biased downwardly. Since the presures of the opposite ends of the probe spool valve 61 will be equal and opposite, accordingly, the probe spool valve will be driven downwardly by its spring 86. At this time pressure will be removed from the probe line 81. This will not mean the end of the exchange motion of the piston adders which will be under control of the hydraulic latch valves 14 which will remain as positioned during the probe portion of the control cycle of the hydraulic logic circuit 20. So long as the exchange continues, the exchange sense piston 35 will remain in its upper position against its spring as will the movesense piston. At a predetermined point, when the exchange velocity ends and the flow of hydraulic fluid due to elimination of pressure differential and the end of flow through the sense pistons 35 and 36, they will both move down to their spring biased lower positions. Accordingly, bleed line 24 will be closed momentarily and bleed line 25 will be closed for the remainder of each cycle of operation of the hydraulic logic unit 20. Line 25 will thereby cause build up of pressure on the upper end of the flow valve 39 as mentioned above and the spring 87 at the top thereof will act to drive the flow valve 39 down. Pressure will build on the line 24 and line 89 from

lines

16 and 688 through the flow valve 39. However, the delay piston 68 and the orifice in orifice check will deferthe build up of the pressure in the lines 24 and the build up of the inlet 89 to move valve 69, and actually the move valve 69 will not be operated at this time, because, a short time later, bleed line 24 will be reconnected by move sense piston 36 to the return 46 and will bleed pressure from inlet 89. Line 688 will apply pressure immediately to the central cylindrical cavity 188 of the exchange spool valve 72 held up by pressure in line 38 and thereby providing pressure on line 90 to the lower end of the aligner latch valve 74. The aligner latch valve 74 will be driven upwardly since the upper end thereof will have low pressure, as on line 75. The pressure had been released as described above. Ac cordingly, the aligner latch valve will release pressure on line 91 to permit the aligner spool valve 92 to be driven upwardly by a spring 93. This will apply pressure to line 189 resetting start spool valve 55 applying pressure from line 116 to reset line 88 to reset all of the pilot valves and will release pressure from line 94 which is connected to the aligners 31 so that one of the members connected to the output of the load shaft can be driven at this point. Further, line 94 is also connected to the velocity control valve 17 in order to reduce the orifice into the piston adders during the period of driving of the load. As the load is now free to move, the piston adders can move and accordingly flow will resume in line 52 (as indicated above in connection with line 24) and for that reason the pressure drop across the move sense piston will resume and the move sense piston will be driven upwardly again thereby bleeding pressure from the bleed line 24. However, the bypass poppet 37 will have pressure released therefrom on line 38 since the flow valve 39 will, as described above, have been driven downwardly thereby connecting line 38 to the return 95. Pressure on line '76 from aligner latch valve 74 in FIG. 2A to the reader 10, FIG. 2D, will operate the reader feed mechanism. In addition, in the purge control in FIG. 2B, 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 interface 13. Air under psig pressure will be driven through the purge inlets 101 across the surface of the diaphragms of the interfaces 102 and out through the reader lines 12 to purge or to drive oil out of the system and to clear and chad and other material from the lines 12, and 112. The remainder of the purge cycle is described below, after discussion of concurrent valve operations.

The pressure will remain on line 76 until such time as the motion of the piston adders ends and the move valve 69 is driven downwardly in final closure of the bleed line 26 by closure of the move sense piston 36, so that at that time, line 71 will drive the exchange valve 72 down removing pressure from line 90 and at the same time applying pressure to line 103 through the orifice of orifice check 104 and delay piston 105 after a time delay of 90 milliseconds, drive the damp valve 73 down against its spring and to apply pressure on line 75 therefrom to drive the aligner latch valve 74 down and remove pressure from line 76 and apply pressure to line 91 and through the orifice in the orifice check 106 and delay piston 107 cause a time delay to run to drive the aligner valve 92 down against its spring 93. The aligner delay piston 107 will require another 120 milliseconds to drive downwardly. Accordingly, final alignment will not occur for some time.

However, referring again to the purge unit, in FIG. 2B, when line 71 is pressurized, the piston 99 will be driven to the right and atmospheric pressure from line 199, to atmosphere, will be permitted to resume inside the purge and

reader lines

101 and 12 so that the diaphragms 102 may be returned to atmospheric pressure. Then when pressure is removed from line 76 as a result of return of the aligner latch value 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 110 which applies positive pressure to the air pressure head 111 for passage through the tape 1 1 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 1 1 will prevent blowing air down into the diaphragms during the purge cycle when air is to be blown in the reverse direction.

AIR READER The perforated tape reader shown in FIG. 2D will operate in ordinary machine shop air typical of industrial locations, which is contaminated with dirt, oil and water. Therefore, cyclic purging of lines 12 is necessary because the reader sense hoses are extremely thin, usually 0.03O inches I.D. making them vulnerable to cloggmg.

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 filifi pdrts 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, suppsaiagthampa is pressiirized with 10 "bsi'gatrs spring loaded air manifold. A hole in the tape will allow its corresponding diaphragm actuated pilot valve to be pressurized 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 117. The tape which is used includes 8 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'for the l6, 8, 4, 2, and 1 inch piston adders would be entered. The head 111 is designed so as to provide air pressure above all 16 holes and underneath the holes would be aligned the various inlets 12 to the diaphragms 102 shown in FIGS. 2E-2H. 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. 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 131 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 13% 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 for communication 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 from the aligner latch valve lower outlet, which is provided for operating the reader. lf pressure were applied to line 76, it would function to pull the toggle lever 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. It should be noted that while the probe pressure is employed for the purpose of driving the air reader, that 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 110 to the air pressure head 111 will have been blocked by the leftward land of the spool valve 98.

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.

It is during this tape advance cycle described above that the pilot valves 85 of the hydraulic system must be physically locked by pressure in line 88 from responding to the tape holes as they move under the air reader head 1 11, and at the same time, the sense hoses 12, 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 99 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 hoses 101 to the port 100 ofthe transferred purge control valve 99 and, at the same time, shut off the air pressure to the air manifold 110 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 psig port 109 provides a reverse air flow through the 16 diaphragm chambers, sense hoses and the air reader head ports with the foreign matter, if any, being 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. In order to accomplish the depressurization, the purge control valve must be returned to its initial position before the return of the isolating valve 98 sealing 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 for exposing all the purge hoses to the atmosphere through port 281. Again at the end of the tape advance cycle the aligner latch valve 74 will be 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 position.

The reset of the isolating valve will permit 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.

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 FIGS. 2E-2H. When pressure is applied above a hole, then one of the diaphragms 102 will operate to cause its associated pilot valve to be driven leftward. This will cause the associated latch valve 14 to be driven leftward also, during the application of pressure to the probe line 81, as the line 84 will be connected to the right-hand side of the central land of the pilot valve 85. Accordingly, the right-hand end of the latch valve 14 will have pressure applied thereto. Referring to latch valve 14-16 on the left-hand side of FIG. 2F, the numeral 14-16 indicates that the latch valve is connected to the 16 inch piston adder by means of

lines

141 and 142. The right hand one of the lines 142 is the one which will have the pressure applied to it in a case in which the pilot valve has been actuated by the reader. It will be seen that the line 142 passes through the velocity control valve 17 in FIG. 21, and if pressure is applied on line 94, then the spool valve 143 will be driven to the right and the orifice through the velocity control valve 17 will be reduced for the longer ones of the piston adders from lengths of 16 inches down to 1 inch. As pressure is applied through line 142, the fluid will flow through line 342 into the space in cylinder 145 to the right of piston 144. If the load is released from alignment or if other pistons are also being displaced at the same time, as in the case of exchange between pistons, then there will be freedom for the cylinder 145 to move relative to the piston 144, and, of course, since the pressure is applied to the right-hand side of the piston and cylinder, the cylinder will move to the right. In the opposite case, the piston 144 would move to the left, if the load were released. In FIGS. 3A and 3B, a graph is shown of the displacement characteristic for the two inch piston adder 146 and the 1 inch piston adder 147. In FIG. 2J, the 1 inch piston adder 147 is shown with its piston 148 extended in cylinder 149, whereas the two inch piston adder 146 is shown with the piston 150 in its collapsed position in cylinder 151. If, for example, it were desired to extend the 2 inch piston adder 146 and to collapse the one inch piston adder 147 during the exchange period, then the orifice provided by the spool valve 143 in the velocity control valve 17 would be retained open and at that time the pressures applied would be on the left-hand

Claims

1. In a mechanism having a relatively fixed member, a movable member and damping means coupled between said movable member and said fixed member for exerting a damping force upon said movable member, the improvement comprising selectively releasable means for positively positioning said movable member relative to said fixed member, during engagement of said releasable means, said movable member being secured to a first end of an incremental drive and control means for actuating said incremental drive during an initial interval of time to cock said damping means in the reverse direction of the ultimate direction of travel of said damping means to occur at the end of a driving cycle of said incremental drive when damping motion of said movable member, arresting means for arresting the distal end of said incremental drive from said movable member, said arresting means being affixed relative to said fixed member at said distal end during cocking of said damping means in the reverse direction from said ultimate direction of travel of said damping means.

2. Apparatus including, damping means including a cylinder and a piston, said piston having a shaft secured thereto, an incremental drive having one of its ends secured to the opposite end of said shaft, and having the other of its ends secured to arresting means for selectively arresting said incremental drive, and control meAns for controlling operation of said incremental drive and said arresting means during an initial interval of time of operaton of said incremental drive causing said incremental drive to cock said damping means in the reverse direction from its ultimate direction of travel to occur during an interval of time subsequent to release of said arresting means.

3. In a mechanism having a relatively fixed member, a movable member and damping means cooperating with said movable member for exerting a damping force thereon, the improvement comprising selectively releasable means for positively positioning said movable member relative to said fixed member during engagement of said releasable means with said movable member, said movable member being secured to an incremental drive and damper control means for actuating said incremental drive during an initial interval of time to cock said damping means in the reverse direction of the ultimate direction of travel of said damping means to occur later at the end of a driving cycle of said incremental drive when damping motion of said movable member, means for arresting a fluid system coupled to said damping means and said incremental drive for automatically arresting said incremental drive by operation of said means for arresting upon the distal end of said incremental drive from said movable member, and said damper control means actuating said incremental drive to cock said damping means prior to each output motion of said incremental drive and final control means for automatically engaging said selectively releasable means for positively applying forces to drive said movable member into a central position subsequently to each output motion of said system.

4. In a damping mechanism having a relatively fixed member, a movable member and damping means coupled to said movable member for exerting a damping force thereon, the improvement comprising said damping mechanism including a selectively actuated locating means including a piston in a piston chamber for positively urging said movable member towards a preselected position relative to said fixed member during actuation of said piston, said piston being mechanically coupled with said movable member by rigid means during urging by said piston of said movable member towards said preselected position, and control means for controlling the sequence operations of said damping mechanism operating said locating means subsequent to damping by said damping means said damping mechanism having its movable member secured to a load, said control means permitting said damping mechanism to provide damping while initially passing beyond said preselected position freely and then said control means subsequently providing accurate positioning by actuating said piston for driving said load to said preselected position, said movable member being secured to an incremental drive and during an initial interval of time said control means actuating said incremental drive to cock said damping means in the reverse direction of its ultimate direction of travel when damping said movable member.

5. Apparatus in accordance with claim 4 including means for arresting said incremental drive, said means for arresting restraining the distal end of said incremental drive from said damping means during said initial interval of time of operation of said drive for cocking of said damping means in the reverse direction from its ultimate direction of travel to occur later.

6. Apparatus in accordance with claim 4 wherein said incremental drive comprises a plurality of pistons in cylinders connected in a series, and said means for arresting comprises means for clamping the distal end of said series to be stationary relative to said fixed member during cocking of said damping means.

7. Apparatus in accordance with claim 4 wherein a control system is coupled to said damping means and said incremental drive for automatically cocking said damping means prior to each motion of said incremental drive and subsequently autoMatically engaging said selectively releasable means for positively positioning said movable member.