Fluid Logic Circuit

Abstract

A NOR fluid logic circuit mechanism comprising an arrangement of diaphragm-controlled valves which have three inputs and which has a single output. This provides effectively a three-input NOR logic element that is preferably made of two injection molded transparent plastic halves that are bonded to a flexible polyurethane membrane between them, the membrane acting as a valve that opens to permit or closes to prevent the passage of air. The proper operation of the device can be seen visually since the area above the diaphragm in the chambers is visible to recognize the position of the device.

Description

BACKGROUND OF THE INVENTION

A particular type of fluid logic element about which this invention has been developed is fully described in the Norwood U.S. Pat. No. 3,318,329. Basically the device is a fluid control apparatus and employs the flexible diaphragm that is interposed between a pair of flow restrictors so as to produce signal amplification or inversion and in which a positive fluid output signal is produced in response to the presence or absence of a control signal. While logic systems utilizing a valve of this particular type can be designed and built up into a variety of configurations to provide all of the basic logic functions, the usual approach creates an inventory problem and is somewhat exemplified by the system that is illustrated in the Brandenberg U.S. Pat. No. 3,407,834.

SUMMARY OF THE INVENTION

A fluid logic module is provided in the form of a three-control input NOR gate that contains five control ridges in five valve chambers. Supply air enters through two paths, a first path containing a resistor from a flow restrictor and through three chambers containing control ridges and a vent for the atmosphere through another resistor or flow restrictor. A second path takes air directly from the supply and passes it into an output chamber containing a ridge and through a second chamber also containing a ridge which vents to the atmosphere. In between these two chambers an output port is created and ducting is provided between the upstream side of the first chamber to the valve of the output chamber and also from the downstream side of the third chamber to the valve of the vent chamber. Additionally the device is constructed in such a way that a transparent area is left above the diaphragm chambers so that a visual indication of the position of the valve diaphragm may be had to determine which way the circuit is operating. By utilizing this particular mechanism additional logic functions such as OR, AND, FLIP-FLOP, NAND, TIME DELAY, ONE-SHOT, and exclusive OR may be provided by interconnecting this basic unit. These basic units, therefore, may be interconnected to execute a large variety of circuits. The assembly is preferably made from a pair of plastic plates into which the valve chambers are formed and to which a nontransparent diaphragm is secured. If desired, only certain chamber areas may be selected for viewing by providing a cover plate with window apertures to show only the selected chambers. A color differential of the bonded surfaces may also be used to help outline the unbonded diaphragm areas to be viewed.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of the basic logic element made in accordance with the invention;

FIG. 2 is an end view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a sectional view taken on line 4--4 of FIG. 1;

FIG. 5 is a sectional view taken on line 5--5 of FIG. 1;

FIG. 6 is a schematic diagram of the device illustrated in FIGS. 1 thru 5 but with the logic ON rather than OFF as in FIGS. 1 thru 5.

FIGS. 7 and 8 are views illustrating the masking of the input chambers with only two windows for viewing the two output chambers; and

FIG. 9 is a schematic diagram showing how the individual elements may be interconnected to provide for the more common logic functions.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 6 the arrangement is illustrated as having a control or supply pressure P.sub.s set in two channels. The first channel includes a free-flow connection as at 12 that leads to a control chamber 13 having a ridge 14 therein and the flow path may be opened or closed by a diaphragm 15. The flow path continues down a duct or conduit 16 which has an output port 17 thence into a second chamber 18 having a ridge 19 therein and a control diaphragm 20 to flow on the other side of the ridge 19 venting to the atmosphere through a vent port 21. The control for this first path consists of a resistor or flow restrictor 30 between the pressure source P.sub.s and a second path. The second path leads from the source of suitably restricted pressure into a first chamber 32 having a control ridge 32 therein, a second chamber 36 with a control ridge 37, a third control chamber 40 with a control ridge 41 therein and thence to an exit resistor or flow restrictor 42. Chambers 32, 36 and 40 have flexible diaphragms 33, 38 and 44 respectively thereacross which are arranged to seat on the ridges 32, 37, 41 respectively as the diaphragm effectively divides the chambers in half. The upper portion of each of the chambers have control ports 34, 39 and 43 therein that may apply pressure to the upper side of the diaphragm. This figure depicts the logic ON and if the two flow restrictor areas 30 and 42 are equal, the pressure between them will be one-half the supply pressure P.sub.s. This is great enough to maintain a closed diaphragm 20 but not enough to close the diaphragm 15. Air, therefore, at supply pressure P.sub.s is directed to the output 17 to act as a signal input. If one or more of the control ports 34, 39 or 43 receives a positive pressure signal, the flow will be blocked in the second flow path and pressure downstream of the control ridge will bleed to the atmosphere through the downstream flow restrictor 42. The pressure upstream will build to the supply pressure P.sub.s and the diaphragm 20 will open and the diaphragm 15 will close. This places the logic in OFF. Broadly a signal to any one of the three input ports produces zero output and conversely all inputs must be zeroed to obtain an output. Therefore, there is diagrammed here a three-input NOR logic element.

The arrangement which has been utilized to physically produce the device just discussed is illustrated in FIGS. 1 thru 5. Referring to these figures, it is seen that the basic logic block consists of a bottom plate 45 and a top plate 46. The chambers 13 and 18 of the first flow path are shown in FIG. 5 and it will be seen that they are located at both the top and the bottom plate, the control portion of the chamber being located in the top plate 46 while the ridges 14 and 19 respectively are located in the bottom plate 45. In a similar but opposite arrangement by referring to FIG. 4 it will be seen that the chambers 31, 36 and 40 have their ridges 32, 37 and 41 located in the top plate 46 while the control chambers are in the bottom plate 45 through which the control ports 34, 39 and 43 respectively pass. Between the plates 45 and 46 are a pair of nontransparent diaphragm elements, one diaphragm element being preferably secured to each place and bonded to the planar portions thereof. In this fashion two input plenums are in effect created, there being a n input plenum 11 in the bottom plate 45 and 11A in the top plate 46, both of them being fed by an input connection which may be a common one as shown in FIG. 6. In the bottom plate 45 there are passages created being noted that the passage duct 12 is created from the input plenum 11 to the chamber 13 and also passage 16 and vent 21 as well as there being shown a pair of output ports 17 for ease in assembling the circuitry into which this logic device will be utilized. The flow restrictors or resistors are located in the top plate 46 and in effect take the form of small passages being indicated at 30 and 42 respectively.

The plates 45 and 46 are preferably molded from a transparent polycarbonate type of material, for example, or any other transparent type of material and the diaphragms which are preferably made from 0.002 inch polyurethane is bonded to the bottom and top plates and these bottom and top plates are held together along the plane of the diaphragm by any suitable means. If the diaphragm is nontransparent and the area at least above the chambers is transparent, one can visually see the presence or absence of input signals and a corresponding condition of the output elements 13 and 18. As illustrative of the manner in which this appears, FIGS. 7 and 8 illustrate the output elements respectively in the OFF condition and in the ON condition. Thus in FIG. 7 the diaphragm 15 has been pushed down by a control pressure tightly against the ridge 14 and in FIG. 8 similarly the diaphragm 20 has been pushed down tightly against its ridge 19 so that this condition is easily detected.

FIG. 9 illustrates some of the basic logic functions that can be achieved by utilizing some of the basic element that has been illustrated and described above. This has been shown schematically and each of the lines going into the logic element represent one of the three input signal ports 34, 39 or 43 and it will be basically understood by those skilled in the art that by interconnecting them in the fashion shown that the function attributed thereto by the legends in the figure will be created. Similarly any basic logic function can be solved by utilizing the NOR gate as the basic device, and it is not intended that we be limited to those merely shown in FIG. 9 by way of example.

Claims

We claim:

1. A fluid control device comprising a block of material having a top plate, a bottom plate, and nontransparent diaphragm means disposed therebetween, said block having inlet port means for receiving a pressurized fluid and at least one outlet port, means defining a first flow path for pressurized fluid within one of said plates and being formed along one face of said diaphragm means, means defining a second flow path for pressurized fluid within said other plate and being formed along the other face of said diaphragm means, said first flow path passing from said inlet port means to said outlet port with a chamber therebetween, part of said chamber being in said top place above said diaphragm means and part of said chamber being in said bottom plate below said diaphragm means, said first flow path passes through that portion of said chamber that has a ridge formed within it against which said diaphragm means may be pressed whereby the output flow is stopped, said ridge being relatively narrow and extending up from the bottom of said chamber and also extending laterally across said chamber with its opposite ends connected to the vertical walls of said chamber, the area of the block above the chamber is transparent whereby the position of the diaphragm may be visually observed to indicate whether the diaphragm is resting on the ridge and showing a line thereacross and thus whether the logic of the fluid control device is in an on or off state.