Hellbaum, R. F.

English

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NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 
WASWGTON. D.C. 20546 
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(NASA CR OR TMX OR AD NUMBEM (CA~EGORY) 
TO: us~/; iczen~arac & w c n n ~ c a ~  ~nroranae~on Division 
Attentions Miss Winnie Me Morgan 
FROMt ~ ~ / 0 f f i c e  of Assivtaqt General Counsel for  
Patent Matters 
SUBJECT~ ~nnouicement of NASA-Owned U. S. Patents i n  STAR 
In accordance with the procedures agreed upon by Code GP 
and Code U S I ,  the attached NASA-owned U. S. Patent is being 
forwarded fo r  abstracting and announcement i n  NASA STAR, 
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The following information is provided: 
U. S. Patent No, 
Government or 
Corporate Employee a Government 
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Source (if  applicable) t NA . 
NASA Patent Case No. r XLA-07391 
NOTE - If th i s  patent covers an invention made by a corporate 
employee of a NASA Contractor, the following is applicablet 
yes 0 NO 
Pursuant t o  Section 305 (a) of the National Aeronautics and 
Space Act, the name of the Administrator of NASA appears on 
the first page of the patent$ however, the name of the actual 
inventor (author) appears a t  the heading of Column No, 1 of 
the Specification, following the words *. . . with respect to 
https://ntrs.nasa.gov/search.jsp?R=19710008104 2020-03-17T02:37:56+00:00Z
B 978 R F HELLBAUM 3,493,004 
L,OFEC A N D  G A T D  FOR FSjUID CIRCUITS 
F i l e d  May 6, l%8 
PIG. 2 
United States Pateamt Offi-ce 3,493,004 Patented Heb, 3, 1970 
3,493,004 
LOGIC AND GATE FOR FLUID CIRCUIm 
Richard F. EIellbaum, Wamplon, Va., assignor to the 
United States of America as represented by the Admin- 
istrator of the National Aeronautics and Space 
Administration 
Filed Ma  6, 1968, Ser. No. 726,898 
fnt. Cl. Fl5c 1/08 
U.S. Cl. 137-81.5 4 Claims 
It is a further object to provide an AND gate which 
produces an output even though considerable disparity 
exists between the two input signals. 
These and other objects of the invention which will 
become apparent up011 a reading of the specification a te  
accomplished by provididg for each input passage a pair 
of output passages, and wall contours such that wail at- 
tachment will occur with flow through either output pas- 
sage, but the design in such that a preference is felt by 
10 the input flow to attach to one of the outputs. The other 
ABSTRACT O F  THE DISCLOSURE output of each of the inputs are connected together to  f o ~ m  a common output. The input passages are arranged 
A logic AND gate having A and B inputs which each so that flow through kither inpuiirnpingeson flow through 
have a pair of outlets, with one of  each of these joined the other when flowing along its preferred path, and in 
together to form a common output. Each of the A and B 15 a direction to cause switching of both to the connected 
inputs is arranged to produce a wall attachment with a outlets, thus producing the ~ N D  output. Cross ventila- 
wall for both its outlets, but is also arranged to have a tion of both the output chambers eliminates sensitivity to 
preferential attachment to a wall of its unconnected out- loading of the AND output. 
let. The A and B inputs are connected to directly impinge Referring now to the specification and particularly to 
on each other in a direction tending to produce a shift of  20 the drawings, FIG. 1 is a schematic of the basic AND 
each input signal from its preferred to  its joined outlet, gate according to the present invention. 
thus yielding a nonproportional AND output. Cross vent- Shown in FIG. 2 is a schematic of another form of the 
ing of the o ~ ~ t p i ~ t  chambzrs results in outputs insenzitive AND gate according to the present invention. 
to load. In FIG. 1 ,  passages 2 and 4 are the input signal pas- 
2s sages for signals A and B, converging into each other 
The h e n t i o n  described herein was made by an em- at  a substantial angle. Each of these input passages 2 and 
ployee of the United States Government and may be 4 has a pair of related output passages 6 and 10 and 8 
manufactured and used by or  for the Government for and 12 respectively, downstream from the convergement, 
governmental purposes without the payment of  any royal- with 10 and 12 joined to form a common output 14. In- 
ties thereon or  therefor. 30 put passage 2 directs fluid signal A into an output cham- 
Thig invention relates to a fluid logic element, and more ber 17, formed by the two sidewalls 18 and 20. These 
particularly to a fluid AND gate. sidewalls are contoured so that preferential wall attach- 
Prior art AND gates are of many ,different configura- ment of the jet occurs with wall 18. This may be accom- 
tions, but basically are of two different types, i.e., a fluid plished in any number of ways, all well known in the 
momentum type in which the t\\o inputs are so alranged 33 flueric art, as by providing a wall contour 18 that deviates 
that &hen both signals are present, an  exchange of  mo- but slightly from the direction of the input flow A. Wall 
mentum causes deviation of each signal stream into a 20, on the other hand, breaks away more  sharply from 
common outlet to produce an AND output. A second input passage 2, and flow must cross a gap 19 wider than 
type utilizes the wall attachment principle for both the 40 that a t  21, so that as a result, if the signal A is unin- 
AND output and each sole output, arranging the passages fluenced by other factors, flow preferentially attaches to 
so that the flow is slightly monostable away 'from the sidewall 18. However, wall 20 is contoured sufficiently 
AND output. A cross passage between the inputs is then smoothly and continuously with respect to passage 2 that 
provided so that when flow occurs in both inputs, the wall attachment of flow from input 2 will occur if the jet 
draw in the cross passages biases each input so that the g5 is influenced toward wall 20, as  will be explained fur- 
jets are both switched to the common AND output. ther herein. 
While in general sati\factory, these devices suffer f ~ o m  Input passage 4 directs fluid signal 4 into output cham- 
some rather substantial disadvantages. The momentum ber 15, formed by the sidewalls 16 and 22. These side- 
exchange type of device produces an output varying pro- wall? are formed so as to have the same relationship with 
portionally with changes in input signal magnitude, gen- the input passage 4 a5 that discussed above with respect 
erally an  undesirable effect for the uses to which si~ch de- to input passage 2. Therefore, fluid signal jet B will prcsf- 
vices are put. In add~tion, gross diffe~ences in the input erentially attach to wall 16, but if influenced toward wall 
4gna1 levels may eliminate the AND output altogether. 22, fluid wall attachment will occur with respect to this 
The second type of prior art AND gate suffers from the ~urface .  
d~awback that the switching from one output to the other 55 In operation, if either signal A o r  B is present without 
niust be accomplished by pressures a fraction of the mag- the other, no flow occurs in outpllt 14, but entirely in 
nitude o f  the primary signals, thus requiring high gain in either output 6 or  8 depending o n  the signal Present, thug 
the sw~tchlng funclron T h ~ s  in turn lead\ to sen\ i t~v~ly  of producing the A . E  at 8 and the B.Z a t  6. Conversely, if 
the device to dimen5ional variat~on\ encountered in nor- flow occur? in both inputs 2 and 4, the interaction of the 
rnal manufdcturing proce\'ies, and hence, these devices 00 jets A and B causes mutual influencing of the jets toward 
tend to be relntively expen\ive Both of these types also s ~ ~ r f a c e s  20 and 22, suck that both jets now become r a t  
ale sensttive to loads an the various outputs tached lo its respedive inner wall. 28 and 22, and all ah 
Therefore, i t  is an object of the present invention to the flow now occurs in output 14, and none in outputs 6 
provide :zn AND gate which prodr~ces acr outprtt l h i l  doe\ nnd 8, thus: yielding the AND function A.B. 
rnot vary proportionately with changes in input signal 65 Analysis of this arrangement will show the several dis- 
magnitude. tinct advantages arising themfrom. Firstly, the output at 
It is a further object to provide an AND gate which 84 is nonprsportional, since once the input jets are shifted 
may be manufactured without holding dimensions to ex- from the outer walls, attachment to the inner walls 20 
ceq4vely close tolerances. and 22 occurs and the flow is completely shifted from ihe 
It is yet another object to provide an AND gate which 70 outputs 6 and 8. Secondly, differenses in magnitude be- 
operates normally regardies? of the level of loading of tween the inputs A and B does aot affect the mode of 
the output devices. operation, since both the output paths of A and B in the 
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tca~.trlr,+nt Ic-\\entng of f:rhric:~tion tolcr,tnce rec~rrttcaricnt\ 
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whencvcl flow C"CLLITL sot@y in s,aid lalplsr p:lnhage; 
, i t t i i  ilicrefore tr~antil;~ciur~ng cost\. mean\ for producing wall artacixment flow into stkid 
A practical tlesign of the AN19 gate according to the second outSet paswges whenever Bow occurs in k t11 
pre4ent invention is shown in FIG. 2. 'This unit incorpcs- said inlet passages; and . 
~,iics !he same basic configuration a \  that shown in FIG. means for providing a ntiid connection between said 
E ,  brit has been vented so  as to elirnim~ate scnsitivily to second outlet passages, whemby a nonpropoxtionai 
loads on the various outpettb, A N D  output is provided. 
This has been accomplished by adding vents 24 and 26 2. The AND gate of claim 1 whenein Said means for 
to ~ h , i n ~ b e r s  15 and $7, so that excess fluid may escape producing wall attachment Wow into said second outlet 
wit-11 otitputs 6 and 8 are loaded o r ,  blmked rather than passages includes a central wail member disposed tfown- 
rnnvirig into oritput 14. 1,) stream of said convergernent and having stirfaces rurtning 
In  additiorr, vent passages 28 and 30 have been added between each of said inlet passages and its respsctive ses- 
w111ch join together a s  a cQrnmQ0 vent 3%. This functions ond sutlet passage. 
to provide complete ventilation when passages 10 apd 3. The 'AND gate d claim 1 further inclrading a vent' ' 
12 are loaded o r  blocked. '%tehas  been found Illat 'the oirtlet between each of said inlet passages and its respec- 
- inc3t.lfion of a single side vent docs riot completely elirni- 20 tive outlet passages. 
flare Icakage into outputs 6 and 8 when loads are imposed 4. 'The A N D  gate of claim 1 further including vent 
at; drr output at 14. The central vent allows excess fiuid mean\ located on both sides of eash of said fl~iid paths 
* o  esc'ipe in  both direcbkons, thus ~ninimiz~ng leakage into downstream of said convergelnent. 
i,li6Eets 6 and 8. 
rlrerefore, i t  can be: seer1 that an A N D  gate has beer1 2: References Cited 
:)I o\ ~ d e d  v ~ i l i ~ h  prudrlces a nonprojl~rtional AND output 
~ t b i c i ~  m~iy  be incxpnsively mqnufa~tured, and which is UNITED STATES- PAThNTS 
i r l ~ ~ n s i i ~ v e  lo load~ngr on the various outpc~ts. 3,266,509 -8/1966 Grocbereta l . - - - - ,  147--81.5 
\vhiat i r  as desired to be secured by ' 3,272,214 Wciirg91 ------------ 1'37-81.5 
X eiiers Patent of the United State? is: . ! . 3,277,915 X0/1966 Dackery ----.------ 137=-81,s 
_ _ L A  iogic AND gate comprising: 3,466,130 1/196X Reader - - - - - - -p----  139-81.5 
firi t  ~ n d  .;ecnnd inlct passages arranged to converge into 31366*13' 1'196X Swarte ------------ 137-81 
tsru h other, each. of said insets h;iving a f i r s t  and a 
i c ~ o n d  nil l let passage doe6,nsiream from said con- M' Primary Examinner 
"ergenrent; :!.; WILLIAM It. CLINE, Assistant Examiner 
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Logic AND gate for fluid circuits Patent

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