US3618891A - Device for selecting extreme value of plural input signals - Google Patents

Abstract

A fluid-operated apparatus for selecting extreme magnitudes, that is, the maximum or minimum magnitudes from several input signals, including a housing which is divided into several uniform chambers which are totally closed for the exception of the input thereto. The chambers are separated by flexible diaphragms carrying actuating projections thereon which transmit the pressure signals to the adjacent membranes or diaphragms, the last actuating means producing a signal corresponding to the extreme value present in one of the chambers by releasing such signal from a fluid source.

Description

United States Patent Inventors Appl. No.

Filed Patented Assignee DEVICE FOR SELECTING EXTREME VALUE OF PLURAL INPUT SIGNALS 6 Claims, 5 Drawing Figs. [1.8. CI 25l/61.2, 235/201 ME, 251/634 Int.Cl Fl6k 31/145 [50] Field oiSearch 251/61, 61.1, 61.2, 61.3, 61.4, 61.5; 235/201 ME [56] References Cited UNITED STATES PATENTS 3,319,644 5/1967 Thorbum 235/201 X 3,335,950 8/1967 Tal et a1 235/201 Primary Examiner-Arnold Rosenthal PATENTEDunv 9 ISYI FIG-1 DEVICE FOR SELECTING EXTREME VALUE OF PLURAL INPUT SIGNALS This is a continuation of application Ser. No. 556,655, filed June 10, 1966, now abandoned.

The present invention relates generally to a fluid control apparatus, and more particularly it relates to a device for automatically selecting extreme values from a plurality of fluid signals of different amplitudes and, which is capable of processing such signals into logical functions.

Devices for automatically selecting extreme values from fluid signals are known. A known such device operates on the principle of power comparison and employs fixedly tensioned elastic membranes which define chambers in a housing. One of the chambers is adapted to receive the input signal, whereas the other chamber contains a nozzle or a valve to which the membrane is mechanically coupled. Such devices may be connected into a system forming a pneumatic series circuit, requiring that the chambers which contain the nozzles or the valves be connected with each other by pneumatic conduits.

The shortcomings of the above-described known system resides in that the presence of nozzles and valves requires mechanical coupling between them and the membranes, furthermore the number of the nozzles or valves should correspond to the number of the anticipated signals. In view of the fact that a large number of nozzles or valves is required to build a relatively simple system, manufacturing costs of such a system are high and its operation, despite the high cost, is unreliable due to the presence of a large number of valves and nozzles which are bound to become clogged after a short time of operation.

' Other devices are also known for processing discrete signals into logical combinations, which employ movable parts such as slides or balls, or the like. An example for the last-mentioned known device is the double return valve which is capable of representing the logical function OR.

1 It is an object of the present invention to provide an improved fluid-operable device for automatically selecting extreme values from a plurality of fluid signals and which is capable of processing of such selected discrete signals into logical functions.

It is a further object of the invention to provide a fluidoperable device for automatically selecting extreme values from a plurality of fluid signals, in which selection of the extreme values is performed solely by the response of flexible members without employing nozzles or valves within the operating chambers.

It is still a further object of the invention to provide a fluidoperable device capable of processing discrete signals into logical functions by employing only simple movable elements without nozzles or valves.

In accordance with the invention the apparatus for the selection of extreme values from a plurality of fluid signals comprises a housing, a plurality of members defining a plurality of successive chambers in the housing, input means for permitting flow of a signal to each of the chambers, means secured to each of the members and movable therewith upon movement of the associated member in response to a signal present in a chamber adjacent the associated member for transmitting movement of one member to an adjacent member, and means responsive to the transmitting means associated with the member of the last one of the successive chambers for producing an output signal.

The invention provides that the members defining the chambers in the housing constitute flexible elements, such as membranes. Each of the membranes is mounted for movement axially in either direction in response to a pressure signal in the chambers at either side of the membrane, and each membrane has a transmitting means carried therewith which is disposed at the side of the associated membrane facing the responsive means.

In accordance with the invention and in one embodiment thereof, the transmitting means comprise projections of a predetermined height which permit actuation of the responsive means when a signal in any one of the chambers has a magnitude larger than the pressure of the fluid in a pneumatic circuit associated with the device, whereby a signal having a maximum value is selected from a plurality of signals of different magnitude.

In another embodiment of the invention, the device is made capable to process the discrete signals into logical functions by providing a mechanical, electrical or optical signal transducer I in cooperation with the projection of the last membrane associated with the last one of the successive chambers, so that if a signal appears in any one of the chambers, the projection will transmit movement of the membrane associated with the chamber where the signal is present to the membranes of the successive chambers and finally to the transducer, whereupon a logical function of the type "OR is produced, due to the fact that the presence of a signal in either one of the chambers is capable to actuate the transducer element.

In another embodiment of the invention the projections transmitting motion of a membrane to the adjacent membranes are so shaped and arranged that a transducer disposed in cooperation with the projection associated with the last membrane of the last chamber of the successive chambers will be actuated only if a signal is present in each of the chambers. Under the last-mentioned circumstances, actuation of the transducer produces a logical function of the type AND.

In a still further embodiment of the invention the logical function OR is produced in a device in which the flexible membranes are replaced by pistons slidably mounted in the housing and each piston defining a chamber within the housing and, carrying a projection similar to the projections described in connection with the above OR embodiment, whereupon presence of a signal in any one of the chambers will cause the associated piston to be displaced, which displacement then transmits motion to the adjacent pistons, whereby a logical function of the type OR" is produced at a transducer pin cooperation with the projection of the last piston.

The invention will become more readily apparent from the following description of preferred embodiments thereof illustrated in the accompanying drawing, in which:

FIG. 1 is a schematic showing of a device for selecting the maximum or largest among a plurality of input signals;

FIG. 2 is a schematic showing of a device, similarly in structure to that of FIG. 1, for processing discrete signals into 0R" function;

FIG. 3 is a schematic showing of a device for selecting the minimum or the smallest from a plurality of input signals;

FIG. 4 is a schematic showing of a device similar in structure to that of FIG. 3, for processing discrete signals into the logical function AND";

FIG. 5 is a schematic showing of a device for processing discrete signals into OR combinations by means of movably arranged pistons or the like.

With reference to the drawing in which like elements are designated by the same reference numerals, and more particularly to FIG. 1, the fluid-operable device for selecting the largest value from a plurality of input signals includes a housing I in which a plurality of membranes 2a, 2b, 2c are mounted and define chambers 6, 7, and 8 in cooperation with the housing walls. It is understood that any number of membranes could be mounted into the housing, but for illustrative purposes, only a device including three membranes is shown. Chambers 6, 7, and 8 each have an input terminal 9', l0, and. 11, respectively. The membranes 2a. 2b and 2c carry projectionlike elements 3, 4, and 5, respectively, which are adapted to move with their associated membranes in response to pressure signals 9, l0 and 1] fed through inputs 9', 10' and II. It is understood that the shape of the projections is a matter of choice and it is the height of the projections which should be correlated with the spacing of the adjacent membranes. The housing 1 has in its top wall portion a recess la formed therein, which has the configuration of a projection associated with any of the membranes and is aligned with the centerline of the adjacent membrane 2a. The projections serve to transmit motion of the membrane to an adjacent membrane. Motion transmission by the projections occurs in one preferred direction to operate a load as hereinafter described, whereas the projections serve to block movement of an adjacent membrane during its movement in the opposite direction.

The housing terminates in a pneumatic circuit portion having a nozzle 12 which is aligned with the projection 5 which is last in the succession of the membranes, projection 5 being arranged to cooperate with nozzle 12 in a. manner that nozzle 12 may be closed or opened by projection 5 under certain conditions hereinafter described. The pneumatic circuit includes a source 14 of pressurized fluid which through a throttle valve 13 flows in the space surrounding the nozzle and into a load circuit (not shown) beyond the nozzle so that an output signal 15 is capable of being developed under certain conditions hereinafter described. Nozzle l2 communicates with a system capable of relieving the pneumatic circuit of pressures when nozzle 12 is not engaged by projection 5, such system preferably being the atmosphere.

During rest position of the device, as shown in FIG. 1, the output signal 15 is zero since projection 5 of the last membrane 2c is out of engagement with the nozzle 12, therefore, any pressurized fluid flowing from source 14 is relieved to the atmosphere through nozzle 12.

The above described extreme value selecting device operates as follows:

Pressure signals 9, 10, 11 are applied to inputs 9, 10, 11' and, for purposes of illustration, it is assumed that signal 10 is larger than the other signals. The output signals must assume the magnitude of the largest signals among the input signals, which is the magnitude of signal 10. Chamber 7 among the uniform chambers will be under the highest pressure. Membrane 2a deflects upwardly until it engages projection la, since the force exerted on membrane 2a from below and directed upwardly as the result of the pressure in chamber 7, is greater than the force exerted on membrane 20 from above, downwardly, and resulting from the pressure in chamber 6 due to the presence of a signal 9. Membrane 2b deflects downwardly and in an extent proportional to the magnitude of the pressure in chamber 7. At the same time projection 4 presses membrane 2b also downwardly due to the fact that the deflection of membrane 2b is greater than the deflection of membrane 20 resulting from the sole effect of the pressure of signal 11 in chamber 8. Projection 5 will, therefore, cover nozzle 12. As a result, the fluid material coming from source 14 cannot escape to the atmosphere. The pressure chamber 30 exerts a force on the bottom of membrane 20. This membrane is, therefore, pressed somewhat upwardly and projection 5 is displaced somewhat from nozzle 12, so that a portion of the fluid material may escape now to the atmosphere over nozzle 12. As a result of this, the pressure of chamber 30 exerted against the bottom of membrane 20 will become less and less and projection 5 will again move closer to nozzle 12. The result is that a balanced condition will set in between the force which moves membrane 20 through the medium of projection 5 downwardly and between the force resulting from the pres sure in chamber 30 against membrane 2c upwardly. Therefore, the output signal will have a magnitude which will equal the magnitude of the largest input signal which, in the illustrating example, is the magnitude of signal 10. The pressure of source 14 must be always larger than the pressure of the largest input signal.

When the magnitude of signal 10 decreases, but it is still larger than any of the other input signals 9, 11, then the gap existing between projection 5 and nozzle 12 in the balanced state will become somewhat larger, and as a result of which, a larger portion of the pressurized material coming from source 14 will escape to the atmosphere. Therefore, signal 15 is again as large as the largest input signal, which is still signal 10.

The present selecting arrangement requires no adjustment or calibration. It is, however, advisable that projections 3, 4 and 5 should be made with a height that they in the inopera tive position nearly engage the adjacent membranes so that their membranes do not require excessive deflection during operation.

The device shown in FIG. 2 is similar in structure to the device of FIG. 1, with the exception that the pneumatic circuit comprising the source 14, the throttle valve 13 and nozzle 12, is replaced by a transducer 16 which might be of an electrically operated device, an optical device or a mechanical plunger. A signal appearing at any of the inputs 9', 10' or 11' will produce a movement of the membranes in a direction of the arrow whereupon the projection 17 of the transducer will be' engaged by projection 5 of the last membrane 20, resulting in the production of a logical function of the type 011"; since actuation of the transducer was due to the presence of a signal in any one of the chambers.

With reference to FIG. 3, the device shown therein represents an apparatus capable of detecting the presence of a signal the magnitude of which is smaller than any of the signals present in the other chambers. To this effect, the device includes a plurality of membranes which are designated by the same reference numerals as those in FIGS. 1 and 2 and which carry at one side thereof projection 21, 22 and 23 which are disposed on the side of the respective membranes facing the nozzle 12 of the associated pneumatic circuit hereinafter described. The membranes on their opposite sides carry spacing elements 18, 19 and 20. Spacing element 18 upon deflection of the membrane, cooperates with the wall of housing 1 whereas spacing elements 19 and 20 cooperate with the projections 21 and 22, respectively. The device of this embodiment includes a pneumatic circuit in which like elements are designated by the same reference numerals as in the pneumatic circuit of FlG. 1, namely a source of pneumatic pressure 14 supplying fluid through throttle valve 13 into the space surrounding nozzle 12 and further continuing into a load (not shown). The nozzle 12, similarly as described in connection with the embodiment of FIG. 1 communicates the pneumatic circuit with a relieving system, such as preferably the atmosphere, when not engaged by projection 23. During an illustrative mode of operation of the device one may assume that one of the input signals, say 10, is smaller than the signal in any one of the other chambers of the device, whereupon membrane 2a deflects inwardly into chamber 7, and membrane 2b also deflects inwardly into chamber 7.

When the pressure in chamber 6 is larger than the pressure in chamber 7, as has been described above and the pressure in chamber 8 is larger than the pressure in chamber 7, membrane 2b deflects upwardly while membrane 20 will deflect downwardly. As a result, the nozzle 12 will be covered by projection 23 and a pressure will build up in chamber 30. This pressure presses the membrane 20 upwardly, whereby also membrane 212 will be able to deflect upwardly. A balanced state will be attained when the pressure in chamber 30 is equal to the lowest pressure in any one of the chambers 6, 7 or 8, which in the illustrative example is the pressure in chamber 7. As a result, the magnitude of the output signal 15 will be equal to the magnitude of the smallest of the input signals. Also here, the pressure of source 14 must be larger than the pressure of the largest input signal in order that a force compensation could be performed so that the output signal could be made equal to the smallest of the input signals.

FIG. 4 is structurally similar to the embodiment of FIG. 3, therefore like elements which are similar to the abovedescribed embodiments and to the one described in FIG. 3, will be designated by like reference numerals. In this embodiment, like in the embodiment shown in FIG, 2, the device dispenses with the pneumatic circuit and instead has a transducer 16 disposed in cooperation with the last projection 23, so that movement of projection 23, will actuate transducer 16 which might be an electrical device, optical apparatus or a mechanical plunger. In view of the description in connection with the embodiment of FIG. 3, it becomes clear that the device of FIG. 4 in order to operate as a logical converter, should have signals present at all inputs, that is, in all chambers, to cause movement of projection 23 downwardly so that a logical function of the type AND could be obtained upon movement of the transducer in the direction of the arrow.

With reference to the embodiment shown in FIG. 5, the housing 1 includes a plurality of pistonlike elements 24, 25 and 26 which slide in fluidtight relationship with the walls of the housing so that each pistonlike element defines within the housing a chamber similarly like the membranes in the abovedescribed embodiments. Each of the chambers includes an input 9', 10' and 11', respectively. The pistonlike elements carry projections 27, 28 and 29 for transmitting motion between each other. The pistonlike elements 24, 25 and 26 are adapted to slide in the housing over a distance corresponding to the distance between the respective inputs and are guided fluidtight in the housing by means, not shown in the drawing. The arrangement of the embodiment is such that presence of a signal at any one of the inputs, that is in any one of the chambers, will cause a movement of the pistonlike elements downwardly in the direction of the arrow, so that transducer 16 will be disposed in cooperating relationship with the last projection 29 and engaged and moved by such projection, whereupon a logical function of the type OR is produced by the transducer element 16 which might be of the electrical, optical or mechanical type.

It is seen that the invention provides a simplified device for selecting extreme values from among a plurality of signals having different magnitudes and devices which are capable of converting pneumatic signals of the above-mentioned type into logical combinations of the type AND without employing movable elements like valves, whereupon the operation of the device is made more reliable and more economical.

Although the invention has been described with reference to specific embodiments thereof, it is not intended that the invention should be limited to such specific embodiments only, but it should be defined by the scope of the appended claims.

We claim:

1. Apparatus operable with a fluid for the selection of the one of a plurality of fluid input signals that has an extreme magnitude with respect to the other signals, comprising a housing, a plurality of unbiased movable pressure-responsive sealing wall members defining a plurality of uniform successive input chambers in said housing, each of said wall members being individually supported in said housing, separate transmitting means secured to each of said wall members and movable therewith upon movement of the associated wall member in response to a signal present in a chamber adjacent said associated wall member for transmitting movement of one member solely in one direction to an adjacent member, each said transmitting means being secured to only one wall member, and means responsive to the transmitting means associated with the member of the last one of said successive chambers for producing an output signal, wherein each said wall member is mounted for movement axially in either direction in response to a pressure signal in chambers at either side of said wall member, each of said transmitting means being disposed at the side of the associated wall member facing said responsive means, wherein each of said transmitting means is mounted for movement to exert a force on the next adjacent wall member only if there is a pressure difference between said adjacent chambers,'whereby said output signal is produced by the pressure in that chamber which has an extreme value of pressure with respect to the pressure in the other chambers.

2. Apparatus as claimed in claim 1, wherein said transmitting means are projections of a predetermined height permitting actuation of said responsive means by a signal in any one of said chambers which has a magnitude larger than the signals in the other of said chambers, whereby the signal having the greatest magnitude is selected from said plurality of input signals.

3. Apparatus as claimed in claim 1, wherein said responsive means comprises a pneumatic circuit including a source of pressurized fluid, nozzle means disposed in cooperating relationship with the transmitting means associated with the wall member of said last chamber and adapted to be sealed by said transmitting means when engaged thereby, said nozzle means relieving saidpneumatic circuit from pressures of said source when not engaged by said transmitting means, and an output terminal for conveying said pressurized fluid to a load means.

4. Apparatus as claimed in claim 1, wherein each of said wall members comprised a piston having said transmitting means disposed thereon, said transmitting means comprising projections of a predetermined height permitting actuation of said responsive means in response to a signal in any one of said chambers, whereby an OR signal is produced by said responsive means.

5. Apparatus as claimed in claim 1, wherein said responsive means is actuated when a signal is present in any of said chambers, whereby an OR" signal is produced by said responsive means.

6. A fluid-operable device for providing an output corresponding to the magnitude of an input fluid signal having an instantaneously extreme magnitude with respect to a plurality of input fluid signals, said device comprising a housing, a plurality of parallel unbiased flexible members individually supported within said housing and defining a plurality of separate successive uniform input chambers within said housing, an input signal port extending through said housing to each of said chambers, force transmitting means affixed to said flexible members for transmitting movement between said flexible members in response to differences in magnitude of input signals applied to said ports, said force transmitting means comprising separate projections affixed to said flexible members, each projection extending in the same direction toward an adjacent flexible member and being unattached to the respective adjacent member, each said projection being mounted to exert a force in only one direction on the adjacent flexible member, and means responsive to movement of the flexible member of the last one of said successive chambers for producing an output signal, whereby said output signal is produced only in response to that input signal which has an extreme magnitude with respect to the other input signals.

Claims (6)

1. Apparatus operable with a fluid for the selection of the one of a plurality of fluid input signals that has an extreme magnitude with respect to the other signals, comprising a housing, a plurality of unbiased movable pressure-responsive sealing wall members defining a plurality of uniform successive input chambers in said housing, each of said wall members being individually supported in said housing, separate transmitting means secured to each of said wall members and movable therewith upon movement of the associated wall member in response to a signal present in a chamber adjacent said associated wall member for transmitting movement of one member solely in one direction to an adjacent member, each said transmitting means being secured to only one wall member, and means responsive to the transmitting means associated with the member of the last one of said successive chambers for producing an output signal, wherein each said wall member is mounted for movement axially in either direction in response to a pressure signal in chambers at either side of said wall member, each of said transmitting means being disposed at the side of the associated wall member facing said responsive means, wherein each of said transmitting means is mounted for movement to exert a force on the next adjacent wall member only if there is a pressure difference between said adjacent chambers, whereby said output signal is produced by the pressure in that chamber which has an extreme value of pressure with respect to the pressure in the other chambers.

2. Apparatus as claimed in claim 1, wherein said transmitting means are projections of a predetermined height permitting actuation of said responsive means by a signal in any one of said chambers which has a magnitude larger than the signals in the other of said chambers, whereby the signal having the greatest magnitude is selected from said plurality of input signals.

3. Apparatus as claimed in claim 1, wherein said responsive means comprises a pneumatic circuit including a source of pressurized fluid, nozzle means disposed in cooperating relationship with the transmitting means associated with the wall member of said last chamber and adapted to be sealed by said transmitting means when engaged thereby, said nozzle means relieving said pneumatic circuit from pressures of said source when not engaged by said transmitting means, and an output terminal for conveying said pressurized fluid to a load means.

4. Apparatus as claimed in claim 1, wherein each of said wall members comprise a piston having said transmitting means disposed thereon, said transmitting means comprising projections of a predetermined height permitting actuation of said responsive means in response to a signal in any one of said chambers, whereby an ''''OR'''' signal is produced by said responsive means.

5. Apparatus as claimed in claim 1, wherein said responsive means is actuated when a signal is present in any of said chambers, whereby an ''''OR'''' signal is produced by said responsive means.

6. A fluid-operable device for providing an output corresponding to the magnitude of an input fluid signal having an instantaneously extreme magnitude with respect to a plurality of input fluid signals, said device comprising a housing, a plurality of parallel unbiased flexible members individually supported within said housing and defining a plurality of separate successive uniform input chambers within said housing, an input signal port extending through said housing to each of said chambers, force transmitting means affixed to said flexible members for transmitting movement between said flexible members in Response to differences in magnitude of input signals applied to said ports, said force transmitting means comprising separate projections affixed to said flexible members, each projection extending in the same direction toward an adjacent flexible member and being unattached to the respective adjacent member, each said projection being mounted to exert a force in only one direction on the adjacent flexible member, and means responsive to movement of the flexible member of the last one of said successive chambers for producing an output signal, whereby said output signal is produced only in response to that input signal which has an extreme magnitude with respect to the other input signals.

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