US3495608A

US3495608A - Fluidic elements and devices thereof

Info

Publication number: US3495608A
Application number: US636100A
Authority: US
Inventors: Robert F O'keefe
Original assignee: Pitney Bowes Inc
Current assignee: Pitney Bowes Inc
Priority date: 1967-05-04
Filing date: 1967-05-04
Publication date: 1970-02-17
Anticipated expiration: 1987-02-17
Also published as: DE1750440C3; DE1750440B2; FR1561035A; DE1799026B2; DE1799026C3; JPS4926224B1; GB1236073A; GB1236074A; DE1750440A1; JPS491358B1; DE1799026A1

Description

R. F. OKEEFE FLUIDIC ELEMENTS AND DEVICES THEREOF 2 Sheet s 1 2i; Hi

80661 1 Weak ATTOe EY Feb. 17, 1970 R. F. OKEEFE 3,495,608

FLUIDIG ELEMENTS AND DEVICES THEREOF Filed May 4, 1967 2 Sheets-Sheet 2 INVENTOR.

Robe/ i f Kee/e l/ko iTTOK/VEY United States Patent 3,495,608 FLUIDIC ELEMENTS AND DEVICES THEREOF Robert F. OKeefe, Trumbull, Conn., assignor to Pitney- Bowes, Inc., Stamford, Conn., a corporation of Delaware Filed May 4, 1967, Ser. No. 636,100 Int. Cl. Fc 1/12; G06d 1/00 US. Cl. 13781.5 7 Claims ABSTRACT OF THE DISCLOSURE A fluidic element in which a stream of fluid medium directed between an emitter and a collector is alternately maintained in a laminar or constrained turbulent mode of operation to obtain a sensible pressure recovery differential at the collector to control other fluidic elements or pressure or flow responsive devices. A plurality of fluidic elements is formed in a plate-like member which is combined with a channeled circuit layer such that a plurality of these layers can be stacked one upon another to form integrated fluid logic circuits for achieving highly complicated control functions.

Cross references Summary of the invention This invention relates generally to improvements in fluids devices, and more particularly to improved means in such devices which permit the interconnection of a large number of devices in a unitary composite assembly to form integrated fluid logic circuits.

A fluid element of the type utilized in the present invention comprises generally an emitter and a collector between which a stream of fluid under pressure is normally maintained, the emitter and collector being disposed at opposite ends of a substantially closed fluid interaction chamber. At least one control port is disposed adjacent to the emitter in position to direct a stream of fluid into the first mentioned stream in such manner as to change the mode of operation of the latter from laminar to constrained turbulent.

In the laminar mode of operation, a relatively high degree of pressure recovery is obtained at the collector, whereas in the constrained turbulent mode of operations a relatively low degree of pressure recovery is obtained at the collector, the differential between the two degrees of pressure recovery being readily sensible, either by mechanical devices or by other similar fluidic elements. The fluidic element is provided with a venting means which communicates with ambient atmosphere and through which the fluid escapes when the fluidic element is in the turbulent mode of operation.

Heretofore, fluidic elements generally of the type above described, and others similar thereto, have been formed in relatively thin plate-like members by means of appropriately shaped grooves and bores in the plate-like member so as to produce a usable device. It is also known to provide a plurality of substantially identical spaced apart fluid elements which can be interconnected in order to provide a wide variety of fluid logic circuits capable of performing any desired control function.

These prior devices have generally fallen into two different categories, in that they either have incorporated ice a plate-like circuit layer having channels therein for permanently interconnecting two more of the fluidic elements, or they have been provided with means for connecting external fluid conducting conduits selectively and changeably to portions of the fluidic elements in order to form a desired fluid logic circuit.

A significant limitation of these prior art fluidic devices is that in both of the above-described types, provision is made, on at least one of the broad faces of the plate-like member and/or a sealing cover member, for external connection to fluid conducting conduits which extend from a source of pressure fluid to one portion of the plate-like member, and from other portions thereof to pressure responsive devices or to other fluidic elements. Thus, it has been impossible prior to the present invention to stack a plurality of individual plate-like members one upon another, each incorporating a plurality of fluidic elements, in order to achieve a composite assembly unit making up an integrated fluid logic circuit.

Another factor which has prevented achievement of such a composite assembly unit is the fact that the venting means which is necessary for the fluidic element to operate in the constrained turbulent mode has likewise been provided in one of the broad faces of the platelike member or cover member, thereby requiring that such broad face be exposed to ambient atmosphere.

These and other limitations of prior art fluidic devices have been eliminated by the present invention, the principles of which are illustratively embodied in a fluidic element generally of the type described above. Thus, there is a plate-like member which the grooves constituting the venting means for the fluidic element are extended to the edge of the plate-like member while remaining generally within or adjacent to the plane of the surface of the plate-like member, thereby communicating with atmosphere at the said edge of the platelike member rather than by means of bores extending laterally through the thickness of the plate-like member. By so venting the fluidic element, or a plurality of them, any member of such plate-like members can be stacked one upon another to form an integrated fluid logic circuit device.

In another aspect of the present invention, the composite assembly unit is provided with one or more channeled circuit layers which interconnect the fluidic elements, the circuit layer being composed of a resilent material so as to function both as the circuit layer and as a sealing layer, thereby avoiding the necessity of supplemental sealing layers or gaskets between other rigid members of the composite assembly.

It is accordingly, an object of the present invention to provide a fluidic element having an operative configuration such that a venting means forming a part of the fluidic element is not obstructed and communicates with ambient atmosphere although the fluidic element is substantially completely isolated from ambient atmosphere.

It is another object of the present invention to provide a fluidic device in which a fluidic element is formed in a surface of a body member having a peripheral edge, and a venting means forming a part of the fluidic element terminates at the peripheral edge for communication with ambient atmosphere although opposite surfaces of the body member adjacent the fluidic element are isolated from ambient atmosphere.

It is still another object of the present invention to provide a fluidic device in which at least one plate-like body member is provided with a plurality of fluidic elements and a resilient circuit layer is combined with a plate-like member to provide a fluid logic circuit sealed from atmosphere except at desired points.

It is yet another object of the present invention to provide a fluidic device in which a plurality of fluidic element plates and circuit layers are stacked one upon another to form unitary composite assemblies having an integrated fluid logic circuit.

These and other objects and advantages will be more readily apparent from an understanding of the following detailed description of preferred embodiments of the present invention when considered in conjunction with the accompanying drawings in which:

FIG. 1 is a plan view, with intermediate portions broken away, of fluidic device constructed in accordance with the principles with the present invention;

FIG. 2 is a fragmentary plan view on an enlarged scale of the fluidic element utilized in the device of FIG. 1;

FIG. 3 is a plan view of a portion of the device illustrated in FIG. 1;

FIG. 4 is a plan view of the circuit layer of the device illustrated in FIG. 1;

FIG. 5 is a fragmentary sectional view taken on the line 55 of FIG. 2;

FIGS. 6 and 7 are schematic cross sectional views illustrating respectively two modified embodiments of the instant invention.

Detailed description Referring now to the drawings and particularly to FIGS. 1 and 2 thereof, the fluidic device 10 comprises a generally flat and substantially rectangular plate-like member 12 which is grooved and perforated as hereinafter more specifically described to provide a plurality of substantially identical fluidic elements 14 formed in a surface 16 of the plate-like member 12.

As best seen in FIG. 2, each of the fluidic elements 14 comprises an elongate fluid interaction chamber 20 through which the fluid is adapted to pass in either a laminar or constrained turbulent mode of operation. An emitter inlet port 22 is disposed at one end of the interaction chamber 20, and a collector outlet port 24 is disposed at the opposite end thereof. The interaction chamber is provided with at least one and preferably a plurality of control inlet ports 26 which communicate laterally with the interaction chamber adjacent the emitter port 22.

Each fluidic element 14 is provided with a main fluid inlet line 28 which communicates with an inlet manifold 30, the latter extending substantially the length of the plate-like member 12, as best seen in FIG. 1. An inlet point 32 is provided in the manifold 30 for introduction of fluid under pressure from any suitable source. Each control port 26 is connected by means of a groove 34 with an inlet point 36 whereby fluid may be introduced into the interaction chamber 20 in a manner more particularly described herein below. Also the collector port 24 is connected by means of an outlet groove 38 with an outlet point 40 which in turn is connected, as more fully described below, to other fluidic elements or to pressure responsive control devices.

The fluidic element 14 is provided with a venting means which extends away from the fluidic element in a manner to communicate with ambient atmosphere while the fluidic element 14 as a whole is essentially isolated from ambient atmosphere. Thus, the fluidic element is provided with at least one and preferably a pair of grooves 42 which communicate with the interaction chamber 20 adjacent to the collector port 24, and extend away from the interaction chamber generally in the direction of fluid flow therethrough but laterally of the outlet point 40. The grooves 42 extend to an edge 44 of the body member of the plate-like member 12 and there terminate, as indicated by numeral 46, to communicate with ambient atmosphere.

The individual fluidic element above described operates in the following manner: a pressure fluid introduced at the inlet point 32, in a manner fully described below, flows through the inlet manifold 30 and the main fluid inlet line 28 and enters the interaction chamber 20 in the form of a laminar jet. The fluid jet impinges on the collector port 24 with a relatively high velocity which allows a relatively high degree of pressure recovery; output flow proceeds through the outlet groove 38 and outlet point 40 to a point of use. The amount of flow and the degree of pressure recovery are determined by downstream load conditions. Unused flow proceeds out through the vents.

If a control fluid is introduced at any one of the inlet points 36, it flows through the connecting groove 34 and is discharged through the corresponding control port 26 into the interaction chamber 20, this control fluid having the effect of changing the fluid jet issuing from the emitter port 22 from laminar to constrained turbulent. In this mode of operation, the fluid from both the emitter port 22 and the control port 26 is vented to atmosphere via the groove 42 and venting outlet 46. The fluid jet from the emitter port now impinges on the collector port 24 with relatively little velocity and corresponding low pressure recovery. By introducing fluid through one of the control ports, the condition of the fluidic element has been effectively changed from on to off.

The mode of operation of the fluidic element is changed from constrained turbulent back to laminar merely by terminating the discharge of control fluid into the interaction chamber 20, thereby effectively again changing the condition of the fluid element from off to on.

The fluidic device 10 illustrated in FIG. 1 incorporates a plurality of substantially identical fluidic elements 14 arranged in spaced parallel relationship. Each fluidic element is independent of all others on the plate-like member 12 except for the venting means, in which the grooves 42 for each element extend divergently away from the in teraction chamber 20 on opposite sides of the output point 40 to a location where the grooves 42 for any two adjacent fluidic elements merge, as indicated by the numeral 42a in FIG. 2. From this point to the edge 44 of the platelike member 12, the grooved portion 42b is common to the adjacent fluidic elements, with the exception of the fluidic elements disposed at either end of the plate-like member. By this construction the maximum venting capacity is obtained with a minimum amount of grooves being formed in the surface 16.

The fluidic element device as illustrated in FIG. 1 can be used in a wide variety of ways depending principally on the type of fluid logic circuit desired. The principal advantage of providing the venting terminal for the fluidic elements along an edge of the plate-like member or element plate, in which the fluidic elements are formed is to facilitate the stacking of one element plate upon another so that a composite unitary assembly can be made up which contains many more fluidic elements than are available on a single element plate. For example a decimal counter might require a circuit logic made up of fifty individual fluidic elements, which could require several element plates stacked one upon another and interconiiected by circuit layers as more particularly desired be- FIG. 5 illustrates the manner in which a typical composite assembly might be made up to form a portion an integrated circuit. Specifically, the element plate 12 is shown in cross section, with the surface 16 containing the fluidic element grooves uppermost. A relatively thin elongate sheet 50 of Mylar or other suitable relatively incompressible but flexible plastic is disposed on the surface 16 of the element plate 12. The sheet 50 as seen in FIG. 3, is provided with suitably positioned

apertures

52 and 54 which permit communication between selected points of the fluidic elements and a circuit layer 56 described below. The function of the flexible sheet 50 is to seal the upper or grooved surface of the element plate 12 in the event that the latter is not perfectly flat when a rigid circuit layer is used, and to prevent the circuit layer from being depressed into the grooves of the fluidic element 14 if the circuit layer 56 is formed of a resilient material.

The circuit layer 56 is disposed on the flexible sheet 50 and is provided with suitable channels and bores which effectively define a predetermined fluid logic circuit which will communicate between at least two individual fluid elements 14. Thus, the circuit layer 56 illustrated in FIG. 4 is provided with a pair of

bores

60 and 62 which are connected by a channel 64, and another pair of

bores

66 and 68 which are connected by a channel 70. The bores and channels above described form a relatively simple fluid circuit for a flip-flop which is shown for illustrative purposes only, the operation of which is explained below.

Disposed on the circuit layer 56 is a cover or sealing layer 72, which may be a relatively thick layer of a suitable rigid plastic, this layer serving to seal all of the channels provided in the circuit layer except at specified locations where communication must be obtained between the fluidic elements 14 and external sources or end points in the overall circuit.

All of the layers above-described are provided with suitably located holes 74 (FIGS. 1, 3 and 4) through which rivets (not shown) may be inserted to maintain the assembly together.

A significant feature of the present invention is the fact that the circuit layer 56 is preferably made of a relatively soft resilient material, for example, rubber. Thus the layer 56 functions now only as a circuit layer but also as sealing layer or gasket, thereby eliminating the need for additional gaskets otherwise necessary if the circuit layer 56 is made of a rigid of noncompressible material.

To fluid logic circuit illustrated in FIGS. 3, 4- and 5 would operate in the following manner when provided with appropriate external connectors as described below. By superimposing FIG. 3 on FIG. 1, and FIG. 4 n FIG. 3, it will be seen that the holes 54 in the flexible sheet 50 align with the outlet points 40a and 40b of the first and second fluidic elements .14 on the element plate 12, and the holes 52 align with the

control inlet points

36a and 36b of said fluidic elements. The

holes

60 and 66 of the circuit layer 56 respectively align with the holes 54 of the flexible sheet '50, and the

holes

62 and 68 repsectively align with the holes 52. Thus communication is obtained between the outlet point 40a of the first fluidic element with the control inlet point 36b of the second fluid element, and between the outlet point 40b of the second fluidic element and the control inlet point 36a of the first fluidic element.

A usable output from the fluidic elements may be obtained by providing bores in the cover plate 72 which are aligned with the

bores

60 and 66 in the circuit layer 56, these bores being indicated by the numerals 80a and 80b in FIG. 5. These bores may be provided with any suitable means, such as bosses, to which external fluid conducting conduits may be attached. Similarly, the several layers shown in FIG. may be provided with bores which will be aligned with the main pressure fluid inlet point 32 in FIG. 1 so that such fluid will be supplied through the manifold 30 to the fluidic elements 14.

Assuming now that pressure fluid is flowing through the main inlet lines 28 of the first and second fluidic elements, and that fluid flow through the first interaction chamber 2011 has been established in the laminar mode of operation, a relatively high degree of pressure recovery will be obtained at the outlet point 40a and fluid will flow through the aligned bores 54 and 60, the groove 64, the aligned bores 62 and 3 6 and enter the interaction chamber b as a control stream, thereby maintaining the jet of fluid flowing through the interaction chamber 20b in a constrained turbulent mode. At the same time a substantial portion of fluid will flow through the outlet bore 80a to be utilized in conjunction with any desired pressure responsive control function. Thus the first fluidic element is effectively on and the second fluidic element is effectively off.

This condition is maintained until such time as a control fluid signal is put into the interaction chamber 20a through any one of the three remaining control fluid ports 26 via an appropriate external connection, such as a series of bores through the several layers abovedescribed which communicate with one of the control inlet points other than point 36a. Such a control fluid jet in interaction chamber 20a will change the main fluid jet therethrough from laminar to constrained turbulent thereby terminating the flow of fluid from outlet point 400! both to the external connection and to the interaction chamber 20b. The latter has the effect of permitting the constrained turbulent fluid flow in interaction chamber 20b to return to laminar, thereby providing fluid flow from outlet point 40b both to an external connection via the bore b and to the interaction chamber 20a through the channel 70, thereby providing a substantial control fluid jet in interaction chamber 20a to maintain the main fluid jet therethrough in a turbulent mode of operation. The first fluidic element is now effectively off and the second fluidic element is effectively on.

This condition can only be again reversed by applying an input control fluid signal to the interaction chamber 20b through an appropriate connection from an external source to one of the control inlet points of the second fluidic element other than point 36b.

The composite unitary assembly as thus far described may be utilized in the manner just described, or with a more complicated fluid circuit associated therewith. However, by appropriate rearrangement of the several layers of the composite and by providing appropriate interconnections therebetween together with appropriate external connections, a very wide variety of fluid circuits may be obtained which will provide extremely complicated control functions.

Referring to FIG. 6, one arrangement is shown wherein an element plate is provided which has fluidic elements formed in its upper face 102. Disposed on the upper face 102 is a sheet 104 of flexible material having a predetermined pattern of holes (not shown), and disposed on the flexible sheet 104 is a first resilient circuit layer 108 having holes and channels in one surface thereof which define a predetermined circuit or circuits which now interconnect at least two or more of the fluidic elements formed in the surface 102. A second resilient circuit layer 110 is disposed directly on the upper face of the first resilient layer .108, the second layer also having holes and channels in one surface thereof which define a predetermined fluid logic circuit or circuits which interconnect either portions of the fluid circuits of the first layer with other portions thereof or directly with selected portions of fluidic elements in the plate 100. A cover or sealing layer 112 is disposed on the upper circuit layer 110 to seal the assembly from atmosphere. The cover member 110 would, of course, be provided with suitable connections for external conduits as described above depending on the type of fluid circuit provided in the circuit layers and the cotnrol functions thereby achieved. FIG. 7 illustrates another arrangement of the parts in which the element plate 200 is an intermediate layer of the composite assembly. Thus, the element layer 200 has fluidic elements formed in its upper surface 202, and a flexible sheet 204 is disposed on said surface, the flexible sheet have holes formed therein at predetermined locations. A first circuit layer 206 having a predetermined pattern of channels and holes formed therein is disposed on the flexible layer 204 so as to interconnect several fluidic elements. A cover member 208 is disposed on the circuit layer 206 and may be provided with suitable connections to external conduits as described above.

Another circuit layer 210 is disposed n the lower surface 212 of the element plate 200, the circuit layer 210 also being provided with bores and channels in a predetermined pattern to provide a fluid circuit or circuits batween selected portions of two or more fluidic elements. It will be understood that the element plate 200 must now be provided with bores through the plate at all fluid inlet and outlet points which interconnect with any holes in the lower circuit layer 210. Finally, another cover layer 214 is provided on the lower surface of the circuit layer 210 in order to seal the composite assembly from atmosphere.

The lower cover plate 214 may also be provided with bores for connection to external conduits, if desired, or the lower circuit layer may be utilized only to interconnect several fluidic elements, with all connections to external conduits being made through the upper cover member 208.

It should be noted that it is functionally immaterial which surface of the circuit layer or layers the interconnecting channels are formed in, whether facing the element plate or away from it, except that this factor may determine whether or not it is necessary to employ a sheet of the flexible but incompressible plastic between a circuit layer and the element plate. For example, in the FIG. 6 embodiment, if the circuit layers were disposed such that the channeled faces of both layers were adjacent, another flexible material sheet would be necessary between the circuit layers to avoid undesired communication betwen various portions of the circuits. This sheet would be in addition to the sheet 104 which is necessary to prevent the resilient material of the circuit layer 108 from being depressed into the fluid elements.

It will now be apparent that the several layers may be arranged in a number of different ways, and that they may be stacked one upon another in repeated sequences in order to provide a degree of complexity or duplicity in circuit arrangement for the most complicated of control functions. This is achieved by providing all interconnecting circuitry within the circuit layers so that external connections, except at the end plates, are avoided, and also by providing for venting all of the individual fluidic elements along an edge of the element plate so that the broad surfaces of the plates can be isolated from atmosphere and placed in intimate contact with other layers in the composite assembly.

It will be apparent from the foregoing that there is provided a fluidic element and devices thereof which achieve the above-mentioned objects and advantages and avoid the limitations of prior art structures.

I claim:

1. A fluidic device comprising (A) a body member having opposed substantially planar surfaces and a peripheral edge,

(B) one of said surfaces having a plurality of grooves formed therein effectively defining a fluidic'element,

(C) said fluidic element having an elongate interaction chamber, an emitter inlet port communicating with one end of said chamber, a collector outlet port communicating with the other end of said chamber, a control means operatively coupled with said one end of said chamber to control the condition of fluid flow through said chamber between laminar and constrained turbulent modes, and a venting outlet means communciating with said other end of said chamber for exhausting fluid from said chamber to ambient atmosphere,

(D) said venting means being defined by a pair of grooves formed in said one surface of said body member which extend away from said chamber generally in the direction of fluid flow through said chamber but laterally of said collector means to said peripheral edge of said body member for communicating with ambient atmosphere whereby when the fluid flow through said chamber is in said turbulent mode the fluid exhaust from said chamber through both said grooves simultaneously, and

(E) means disposed on said one surface of said body member for sealing all said grooves from ambient atmosphere on said one surface of said body member.

2. A fluidic element as set forth in claim 1 wherein said grooves extend divergently away from said chamber on opposite sides of said collector outlet port and terminate at said peripheral edge of said body at spaced apart locations therealong.

3. A fluid device comprising (A) an elongate body member having opposed substantially planar surfaces and a peripheral edge,

(B) one of said surfaces having a plurality of grooves formed therein effectively defining a plurality of substantially identical spaced apart fluidic elements, said fluidic elements being generally elongate and arranged in parallel relationship to each other,

(C) each of said fluidic elements having an elongate interaction chamber, an emitter inlet port communicating with one end of said chamber, a collector outlet port communicating with the other end of said chamber, a control means operatively coupled with said one end of said chamber in position to control said chamber for exhausting fluid from said chamber between laminar and turbulent modes, and a venting outlet means communicating with said other end of said chamber for exhausting fluid from said chamber to ambient atmosphere.

(D) said venting means for each fluidic element being defined by a pair of grooves formed in said one surface of said body member which extend away from said chamber generally in the direction of fluid flow through said chamber but laterally of said collector means to said peripheral edge of said body member for communicating with ambient atmosphere whereby when the fluid flow through said chamber is in said turbulent mode the fluid exhausts from said chamber through both said grooves simultaneously and is vented to atmosphere from all said fluidic elements along a common edge of said body member, and

(E) means disposed on said one surface of said body member for sealing all said grooves from ambient atmosphere on said surface of said body member.

4. A fluidic device as set forth in claim 3 wherein said plurality of fluidic elements are disposed on said elongate body member in spaced substantially parallel relationship, and wherein said venting grooves of each fluidic element are formed to merge with the adjacent venting grooves of adjacent fluidic elements at a location spaced from said other end of said chamber, each venting groove being common to two adjacent fluidic elements beyond said location. 7

5. A composite assembly unit for defining a plurality of interconnected fluidic elements, said unit comprising:

(A) a relatively thick fluidic element plate having upper and lower surfaces, said upper surface being grooved so as to at least partially define a plurality of separate fluidic elements,

(B) a relatively thin sheet of flexible but relatively non-compressible plastic material disposed over said grooved upper surface of said plate, said sheet having holes therein at predetermined locations so as to effectively communicate with selected portions of saidfluidic elements,

(C) a relatively thick circuit layer of resilient compressible rubber-like material disposed over said flexible sheet, said circuit layer having a plurality of circuit channels formed only in the face of said layer opposite from said flexible sheet and having bores extending through said circuit layer which communicate with said channels and with said holes in said flexible sheet whereby said circuit channels together with said bores and said holes in said flexible sheet effectively define a predetermined fluid circuit between at least two of said fluidic elements, and

(D) securing means for securing said plate, flexible sheet and circuit layer together.

6. A composite assembly unit as set forth in claim 5 further including a second circuit layer of resilient material disposed on said first mentioned resilient layer, said second circuit layer having a plurality of closed circuit 9 10 channels formed therein which operatively interconnect at 3,362,421 1/1968 Schaffer 13'/81.5 least some of said fluidic elements in a predetermined 3,366,131 1/ 1968 Swartz 137-815 manner. 3,384,115 5/1968 Drazan et al. l37-8l.5 XR

f 7. A composite assembly unit as set forth i1 1 claim 5 OTHER REFERENCES urther includlng a second circuit layer of resillent ma- 5 terial disposed on the side of said fluidic element plate Langley f M Pnelmfatlc Loglc Packopposite from said flexible sheet, said second circuit layer age, Technlcal Dlsclosure Bunch, 61 5,

having a plurality of closed circuit channels formed there- October PP- 31 in which operatively interconnect at least some of said Stelner: Unlversal Modular System for Pneu fl idi elements in a predetermined manner 10 matic Switching Controls, Process Control and Automation, vol. 11, No. 7, July 1964, pp. 310-312.

References Cited UNITED STATES PATENTS SAMUEL SCOTT, Primary Examiner 3,229,705 l/1966 NOIWOOd l3781.5 15 U.S. Cl. X.R. 3,272,214 9/1966 Warren 13781.5 3 0