US3420254A

US3420254A - Pneumatically sampled serializer

Info

Publication number: US3420254A
Application number: US468217A
Authority: US
Inventors: James A Machmer
Original assignee: International Business Machines Corp
Current assignee: International Business Machines Corp
Priority date: 1965-06-30
Filing date: 1965-06-30
Publication date: 1969-01-07
Anticipated expiration: 1986-01-07
Also published as: GB1094450A; FR1485867A

Description

Jan. 7, 1969 J. A. MACHMER ,4

PNEUMATICALLY SAMPLED SERIALIZER Filed June :50, 1965 Sheet of 2 JAMES A. MACHMER ATTORNEY.

7, 1969 J. A. MACHMER 3,420,254

7 PNEUMATICALLY SAMPLED SERIALIZER Filed June 30, 1965 Sheet 2 of 2 FIG. 3

United States Patent 3,420,254 PNEUMATICALLY SAMPLED SERIALIZER James A. Machmer, Lexington, Ky., assignor t0 International Business Machines Corporation, Armonk,

N.Y., a corporation of New York Filed June 30, 1965, Ser. No. 468,217

US. Cl. 137-815 ltl Claims Int. Cl. FlSc 3/04 ABSTRACT OF THE DISCLOSURE Pneumatic signalling pulses are reliably converted into electrical pulses by a diaphragm operated switch provided with a combination of fluid damping and a dual spring rate support for an electrical contact. The fluid signal pulses are derived from a mechanical distributor that sequentially samples the output of a plurality of pure fluid latches to provide for serial transmission of data having parallel significance.

Disclosure of the invention The serializer of my invention employs a single sophisticated fluid-to-electric transducer in combination with a novel fluid commutator mechanism to achieve low cost reliable conversion of parallel data signals into serial form.

Coded space-mark data is employed in both serial and parallel form by various data handling mechanisms. Typewriters, tape readers, and similar local mechanisms usually operate on data in parallel form, Whereas communications systems and computers find it more convenient to handle data in serial form, thus minimizing the number of data conduits which must be provided. Interfacing a parallel data handling system with a serial data handling system requires some mechanism for serializing or converting the data from one form to the other. Serializing mechanism is ordinarily required to inject synchronizing data commonly in the form of start and stop bits to permit the mechanism receiving the serial data to properly recognize the data channels of a received signal.

Existing serializing mechanism commonly takes the form of electric commutation, or more commonly electronic shift registers which are controlled by a precise time base. Existing systems, however, require a basic electronic power supply in addition to the electronic elements for performing the serializing function. In a system such as a wholly mechanical, or mechanical and pneumatic system, where an electronic power supply does not exist, the cost of the electronic serializer mechanism becomes prohibitive.

Accordingly, it has been an object of my invention to provide comparatively low cost reliable serializing mechanism for use particularly in systems lacking a separate electronic power supply.

Another object of my invention has been to provide serializing mechanism for use in a pneumatic or other fluid data handling system.

A further object of my invention has been to provide a versatile and inexpensive fluid-to-electric transducer for converting high frequency fluid pul es into electrical signals of precisely controllable duration.

One concept of my invention relates to the use of pure fluid latches or similar fluid actuated and fluid controlling bistable devices for temporary storage of data presented in parallel, together with a rotating fluid sampling commutator that is driven by a synchronous motor. The synchronous motor, usually available for other purposes, defines a convenient time base. The commutator sequentially delivers data representative fluid pulses to a single transducer for generating electrical output signals. By this concept it becomes practical to provide a highly reliable transducer without unduly adding to the overall cost of the mechanism.

Another concept of my invention involves the use of a specific pneumatic sampling commutator that sequentially engages coplanar sampling ports in a face-to-face relationship, thus providing an especially simple construction from both a parts manufacturing and assembly standpoint.

Another concept of my invention involves the particular fluidto-electric transducer wherein a combination of fluid damping by a restricted orifice, and dual spri lg rate support for an electric contact, provides a rapid bounce-free circuit control that is readily and precisely adjustable to permit accurate equalization of ouput signal length.

The foregoing and other objects, concepts and advantages of my invention will be apparent from the following specific description of a preferred embodiment thereof wherein reference is made to the accompanying drawings of which:

FIGURE 1 is a partially exploded perspective view of a serializer constructed according to my invention as operatively connected with a typical schematically shown data source;

FIGURE 2 is a perspective view of a part of the mechanism shown in FIGURE 1 showing a surface construction that does not appear in FIGURE 1;

FIGURE 3 is a cross-sectional elevational view of the mechanism shown in FIGURE 1 and taken along line IIIIII thereof, and

FIGURE 4 is an enlarged cross-sectional view of a portion of FIGURE 3 illustrating some specific construction details thereof.

In FIGURE 1 there is shown a partially exploded perspective view of a serializer or converter S constructed in accordance with this invention. The serializer S is shown constructed to receive information from a typical data source such as a tape reader R that generates fluid data pulse signals in fixed channel parallel space-mark coded form, and convert the code into serial-form including, if desired, synchronizing start and stop bits. The path of data flow may be traced from the source R to data storage block 10 through parallel fluid channels or signal input conduits 11, then through distributor block 30, serially through rotating commutator 40 to fluidelectric transducer 50 and to electrical output conductor C.

Data storage block 10 The data storage block 10 is made up of a plurality of bistable, fluid actuated, fluid output devices that preferably take the form of pure fluid latches 20 of the construction shown in FIGURE 3. Each latch 20 includes a supply portion or air source 21 that delivers a gaseous jet to either of two

output conduits

22 or 23. The output conduits 22 are positioned along straight line 12 for ease of communication with the distributor block 30.

The latch 20 is constructed according to known principles whereby the jet, once established in flow through one of the

output conduits

22 or 23, will remain in that output conduit until an input signal is received to switch it to the other output conduit. Switching signals in the form of fluid pulses are applied to data signal conduit 24 and to reset conduit 25 to respectively enter and clear data from storage. Overload or dump conduit 26- is provided to prevent reswitching of the fluid jet which might be induced due to loading by the relatively closed passageway presented by the serializer mechanism. Also, suitable vents 27 and 2.8 are provided to insure that the latches 20 will be bistable. The signal conduits 11 from the tape reader R are connected individually to the conduits 24 of the respective latches 20. As shown for convenience, the presence of fluid flow in a conduit 11 indicates a space signal and the absence of flow indicates a mark signal. The latches 20 normally direct flow through output conduit 23. A space signal received in a conduit 11 switches the output flow from conduit 23 to conduit 22. The reset conduits 25 are supplied from a common manifold 13 formed in the storage block and having an inlet 14 (FIGURE 1) communicating externally of the storage block and conveniently aligned with latch output conduits 22.

One latch is provided in the storage block 10 for each channel of the parallel input code and in addition a latch 15 is provided to generate a start bit having flow pressure characteristics similar to those of the latches 20. Start bit latch 15 is generally identical to latches 20, but has no reset conduit or vent 27. The asymmetric lack of venting causes the latch 15 to produce a con tinuous flow or space signal at its output 22..

Distributor block The distributor block 30 is formed with internal fluid flow signalling pathways 31 that communicate individually by inlets 31a with output conduits 22 and terminate at their other end in a sampling port 33 formed in an enclosure plate 32. All of the sampling ports 33 lie in a common plane at the surface of the closure plate 32, and on a common circular are 34 that is centered about an axis 35.

In addition to signalling pathways 31, the distributor block contains a reset control pathway 36 having a supply portion 36a that continuously receives fluid from a port 16 connected to supply portion 21 and a delivery portion 36b that is fluidly connected to reset manifold 13 through inlet 14. The supply portion 36a terminates in an outlet port 360 and the delivery portion commences with an inlet port 36d, both of which preferably lie in the plane of sampling ports 33.

The distributor block 30 also includes a stop bit port 37 that is located on are 34 and in the plane of the sampling ports 33. The stop bit port 37 is vented to atmosphere at 38 through the distributor block 30 to provide a mar signal having a characteristic similar to that generated by the latches 20.

Rotating commutator 40 The commutator 40 is rotatable about axis and has an operating surface 41 that abuts or effectively lies in the plane of sampling ports 33. The operating surface 41 includes an elongated slot or conduit means 42 extending radially from an outlet portion 43 adjacent axis 35 to beyond are 34 to provide sequential communication with the sampling ports 33. The fluid received by slot 42 from sampling ports 33 is delivered to a center bore or supply portion 44 in the distributor block 30.

The commutator is driven at a predetermined rate by a timing shaft 45 when connected thereto by single revolution clutch 46 that is activated cyclically by an electromagnet 47 each time data is presented to the storage block 10. The timing shaft 45 is driven by a synchronous motor (not shown) of the type that would be available in the reader R or other basic mechanical apparatus.

The commutator 40 also includes valve means 48 provided by an open-sided bridging slot 49 in the operating surface 41 for controlling fluid communication between ports 36c and 36d of the reset pathway 36. The location of slot 49 is such as to permit flow through pathway 36 at the end of each cycle.

Transducer 50 (FIGURE 2) Signal fiuid received by bore 44 is delivered through a variable volume chamber 52. A diaphragm or other movable wall 53 defines one end of chamber 52 and moves in response to flow into and out of the chamber.

The diaphragm 53 operates an electric switch 54 to generate an output signal in conductor C. The switch means 54 is shown as normally closed to provide a mark signal when no signal fluid is supplied to bore 44. Obviously, the principles of the switch construction can be applied to a normally open switch if desired. The switch means 54- includes a substantially rigid electrical contact member 55 mounted adjacent the diaphragm 53 and an electrical contact member 56 that is operatively connected in a force transmitting relationship with the diaphragm 53 for bidirectional movement therewith through a range m by a biasing resilient leaf spring 57. The movable contact member 56 is itself resilient and has an elongated contact surface 56a that is oriented at an angle a of about 45 to the direction of relative movement between the

contact members

55 and 56. The acute angle orientation permits limited relative sliding movement between the contact members at one extreme of the movement range m to assure complete bounce-free contact action and to permit a controlled length contact closure. Bounce of the contact is eliminated by the frictional dissipation of energy between the contact members and by permitting the storage of energy only in the moving contact member 56. The length of contact closure is controlled by fixed-contact adjusting screw or stop 58 that positions the contact member 55 in opposition to return spring 5811.

The length of the space signal or contact open time is also made adjustable to permit accurate time-balancing of the mark and space signals. Space length adjustment is accomplished by limiting the movement range m by adjustable stop or limit screw 59 and permitting limited relative movement between the

contact members

55 and 56 after the stop 59 has been reached. The stop 59 engages a point 57a on the contact supporting leaf spring 57 that is substantially coincident with the point of engagement between the spring 57 and the contact member 56. The leaf spring 57 is mounted on one end in fixed end support 57b and normally flexes about point 57c. When spring 57 encounters stop 59 it becomes ineffective and further movement of the diaphragm 53 is opposed by the greater spring resistance of low mass spring contact 56 that acts against diaphragm 53 through a very short lever arm. This action has two beneficial effects. First, it softens the stopping force with the stop 59 to prevent bounce, and second it permits controllable distribution of the total transmitted energy between the low effective spring rate of spring 57 and the higher effective spring rate of the contact 56 itself. This latter effect permits the storage of some controlled amount of motion that must be returned and thus gives the bit controlled length, but with a minimum of stored energy and inertia effects.

Operation of the mechanism thus described is as follows. Prior to each operating cycle, all latches 20 are in their reset state and the jet from source 21 flows out conduit 23. The commutator 40 is positioned to connect chamber 52 with atmospheric vent 38, thus allowing switch means 54 to be closed. When the tape reader R generates pneumatic pulses in conduits 11 in accordance with a particular punched code read in parallel, it gencrates a short transmit cycle signal which is applied to magnet 47 to pick clutch 46 and initiate clockwise rotation of the commutator 4t). Pulses in conduits 11 set respective latches 20 causing flow out of associated sampling ports 33. The slot 42 in commutator 4t} first traverses the sampling port 33 of the pathway 31 associated with the start bit latch 15 which, as indicated above, is always in the space state. A fluid pulse is, therefore, transmitted to the transducer 50 through the slot 42. The rate of fluid fiow into chamber 52 is limited by restriction 51, thus conttrolling the rate of leftward movement of diaphragm;53fc

and contact member 56; Thefirst motion of flexible;

tact member 56 does not cause separation from rigid contact member 55. Further movement, however, does cause separation to initiate generation of an electrical space signal. Continued movement brings the support spring 57 into contact with stop 59 and effectively reducing, but not eliminating, the flexibility of parts opposing further movement of diaphragm 53 to permit limited further movement thereof.

Slot 42 is rotated into communication with the next succeeding sampling port 33 at a predetermined time governed by the synchronous motor drive of shaft 45. If a mark signal is called for, the sampling port will be at substantially atmospheric pressure, thus providing a vent for chamber 52. Flow from the chamber 52 and diaphragm velocity is limited by restriction 51 and movement of the contact member 56 follows in reverse, the sequence spelled out above. Any remaining tendency to bounce is eliminated by sliding of contact portion 56a against rigid member 55. The relative length of mark and space signals is thus controllable by

stops

58 and 59 which determines the amount of limited arrested motion per mitted at both ends of movement range m. Continued rotation of the commutator 40 brings the radially outward end of slot 42 into serial communication with each of the sampling ports 33 until all have been traversed. After a single IGVOlULiOIl of the commutator 40, clutch 46 will stop rotation, positioning slot 49 across ports 36c and 36d to communicate reset fluid manifold 13, thus preparing the latches to receive a second input.

Those skilled in the art will appreciate that I have provided a neumatic data serializer employing pneumatic latches as storage elements to supply a pneumatic com mutator with parallel data to be converted by commutation to serial data in the form of pneumatic pulses. It will also be understood that I have provided an improved fluid-electric pulse transducer for converting individual pulses into precise controllable squarewave electrical output pulses. While specific preferred structure has been shown herein for purposes of illustration, it will be understood that the principles of my invention are not limited thereto, and that various modifications can be made within the scope of this invention as set forth in the appended claims.

I claim:

1. Apparatus for converting data in parallel space-mark coded form having a fixed plurality of channels into serial electrical coded form comprising:

a plurality of bistable devices, each having a fluid output indicative of its existing operational state, there being one bistable device for each of the parallel channels and individually associated therewith to operate in its respective stable state in response to space and mark information in its associated channel,

a fluid-electric transducer for converting a fluid signal into an electric signal,

conduit means cooperable with said transducer and said fluid output of each of said bistable devices for providing individual communication therebetween, and

means operable to cause a predetermined timed sequential cooperation of said conduit means with each of said bistable devices.

2. Apparatus as defined in claim 1 wherein said fluidelectric transducer comprises:

a variable volume chamber having at least one movable wall and a fluid signal supply portion connected to said conduit means,

metering orifice means in said supply portion for limiting the rate of flow into said chamber,

a substantially rigid electrical contact member mounted adjacent said movable wall,

a low mass, resilient movable electrical contact member assembled in a force transmitting relationship with said movable wall for movement therewith between extremes of a range of movement, and resilient means supporting said movable contact member in position to engage said rigid contact member at one of said extremes,

one of said contact members having an elongated contact surface portion that is oriented at an acute angle relative to the direction of movement of said movable contact member to permit substantial relative movement between said contact members while they are in mutual engagement.

3. Apparatus as defined in claim 2 wherein said resilient support means comprise an elongated leaf spring fixedly supported adjacent one end thereof and connected at a first position along its length distal from said one end to said movable contact member for urging said movable contact member towards said movable wall, and further comprising an adjustable stop positioned to engage said leaf spring substantially at said first position when said movable contact is in the other of said range of motion extremes.

4. Apparatus for converting data in parallel space-mark coded form having a fixed plurality of channels into serial electrical coded form, comprising:

a plurality of bistable pure fluid latches, each having a fluid output conduit for either supplying or not supplying fluid flow according to its existing operational state, there being one fluid latch for each of the parallel channels and individually associated therewith to operate in its respective stable states in response to space and mark information in its associated channel,

conduit means cooperable with said transducer and said fluid output conduit of each of said pure fluid latches for providing individual communication therebetween, and

means operable to cause a predetermined timed sequential cooperation of said conduit means with each of said fluid latches.

5. A fluid-electric transducer responsive to a source of bi-level fluid information compirsing: conduit means fluidly connected to said source of fluid information,

a variable volume chamber having at least one movable wall and a fluid signal supply portion fluidly connected to said conduit means,

a low mass, resilient, movable electrical contact member assembled in a force transmitting relationship with said movable Wall for movement therewith between extremes of a range of movement, and positioned to engage said rigid contact member at one of said extremes, and

one of said contact members having an elongated contact surface portion that is oriented at a small angle relative to the direction of movement of said movable contact member to permit substantial relative movement between said contact members while they are in mutual engagement.

6. A fluid-electric transducer as defined in claim 5 wherein said support means comprises an elongated leaf spring fixedly supported adjacent one end thereof and connected at a first position along its length distal from said one end to said movable contact member for urging said movable contact member toward said movable wall, and

an adjustable stop positioned to engage said leaf spring substantially at said first position when said movable contact is in the other of said range of motion extremes.

7. Apparatus for converting data in parallel space-mark coded form having a fixed plurality of channels into serial electrical codded form comprising:

a first plurality of bistable devices, each having a fluid output indicative of its existing operational state, there being one bistable device for each of the parallel channels and individually associated therewith to operate in its respective stable state in response to space and mar information in its associated channel,

individual flow pathways, individually fluidly connected to the fluid output of said bistable devices, each pathway terminating in an end portion that lies on a common circular arc,

a fluid-electric transducer for converting a fluid signal into an electric signal, and

a commutator rotatable about an axis coincident with the center of said circular arc and having conduit means therein for sequentially cooperating with said end portions of said pathways during rotation of said commutator, said conduit means having an outlet portion in fluid communication with said transducer for delivering the fluid flow received sequentially from said pathways to said transducer.

8. Apparatus as defined in claim 7 further comprising:

means for resetting said bistable devices to a common state comprising a fluid pathway for delivering a reset fluid signal to each of said bistable devices and valve means carried by said commutator and cooperable with said pathway for selectivity permitting flow of reset fluid to said bistable devices when said commutator is positioned in a predetermined angular position.

9. Apparatus for converting data in parallel spacemark coded form having fixed plurality of channels into serial electrical coded form comprising:

a data storage block having a plurality of bistable fluid latch flow control means formed therein, each fluid latch having a fluid output conduit communicating externally of said block, all of said fluid output conduits lying substantially in a straight line along one edge of said block,

signal input means for selectively setting at least some of said fluid latches individually according to spacemark data,

a distributor block having a plurality of input conduits,

a plurality of flow pathways corresponding in number to the output conduits of said storage block, formed in said distributor block and having inlets communicating externally thereof corresponding in position to the output conduits of said storage block, each of said pathways terminating in a sampling port positioned along a common circular arc, said sampling ports communicating externally of said distributor block and lying in a common plane,

a bore extending along the axis of said arc through said distributor block,

a commutator rotatable about said axis and having an operating surface lying substantially in the plane of said sampling ports, said commutator extending outwardly radially from said axis to beyond said circular arc and further including a radially extending open edged slot formed in said operative surface and extending between said bore and said are to provide fluid communication between individual sampling ports of said distributor block and said bore, and

fluid-electric transducer means fluidly connected to said bore for converting fluid pulses supplied therefrom into electrical signals.

10. Apparatus as defined in claim 9 wherein each of said fluid latches includes a reset conduit for resetting the associated latch to a common state,

said data storage block includes a manifold fluidly communicating with each of said reset conduits,

said distributor block includes a reset pathway having a supply portion continuously connected to a source of fluid flow and terminating in an outlet lying in the plane of said sampling ports and a delivery portion in fluid communication with said reset manifold and having an inlet lying in the plane of said sampling ports, and

said commutator further includes an open-sided bridging slot for connecting said outlet and inlet portions of said reset pathway when said commutator is in a Zilnglli: angular position relative to said distributor References Cited UNITED STATES PATENTS SAMUEL SCOTT, Primary Examiner.

U.S. Cl. X.R. 200-83; 235-201