US2606022A - Door operation and control - Google Patents
Door operation and control Download PDFInfo
- Publication number
- US2606022A US2606022A US27754A US2775448A US2606022A US 2606022 A US2606022 A US 2606022A US 27754 A US27754 A US 27754A US 2775448 A US2775448 A US 2775448A US 2606022 A US2606022 A US 2606022A
- Authority
- US
- United States
- Prior art keywords
- door
- piston
- fluid
- valve
- cylinder
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E05—LOCKS; KEYS; WINDOW OR DOOR FITTINGS; SAFES
- E05F—DEVICES FOR MOVING WINGS INTO OPEN OR CLOSED POSITION; CHECKS FOR WINGS; WING FITTINGS NOT OTHERWISE PROVIDED FOR, CONCERNED WITH THE FUNCTIONING OF THE WING
- E05F15/00—Power-operated mechanisms for wings
- E05F15/50—Power-operated mechanisms for wings using fluid-pressure actuators
- E05F15/53—Power-operated mechanisms for wings using fluid-pressure actuators for swinging wings
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S60/00—Power plants
- Y10S60/911—Fluid motor system incorporating electrical system
Description
Aug. 5, 1952 J. H. VANDER VEER ETAL 2,606,022
DOOR OPERATION AND CQNTRQL Filed May 18, 1948 5 Sheets-Sheet 1 IN V EN T 0R. dam/Al- %./D :e Val-ed BYCk eu; (M 5 5557 @fi g- 5, 1952 J. H. VANDER VEER ETAL 2,606,022
DOOR OPERATION AND CONTROL Filed May 18. 1948 s Sheets-Sheet 2 73 J 5 F';:| 2/ as 64 3\ f 66 E latented Aug. 5, 1952 UNITED STATES John H. Vander Veer, Westfield, and Cyrus W.
Bassett, Port-au-Peck, N. J assignors, by mesne assignments, to National Pneumatic 00., Inc., Boston, Mass., a corporation of Delaware Application May 18, 1948, Serial No. 27,754 v 4 Claims. (Cl. 268-66) This invention relates to door operation and control, and particularly to a system providing a plurality of control methods applicable to'a door, to cause it to move from a closed to an open position, to remain in such open position for a selected definite interval or for a selected indefinite interval, and to cause it to return to the closed position after such interval.
One object of the invention is to provide a novel method of controlling the operation of a door, which novel method involves the utilization of three power applying agencies individually or conjointly, according to the choice of the operator or depending upon prevailing conditions, one power applying agency being a fluid motor (in the embodiment chosen for exemplification herein), a second power applying agency being a spring motor, and the third power applying agency being the operator himself.
Such operator may be a regularly assigned attendant of the door, on one occasion, and a mere transient user of the door on other'occasions. Thus, for example, when the invention is applied to the operation of a door controlling passage from one railway car to the succeeding car, in a train of cars, the controls may be manipulated by train passengers, successively, to facilitate their passage through the train, and
' alsoby a train porter, or other attendantwho may desire to have power applied to hold the door open (independently of continuous effort on his own part) for an interval of indefinite duration, 50 that a number of pieces of baggage can be carried through the door-way successively,
before application of door closing effort by the.
operating and control mechanism for such door,
functioning inaccordance with the present in+ vention; and
-F igs. 2 to 5, inclusive: are schematic illustra-i tlqns showingrhow the mechanismof Fig. lurespends differently todifferent situations, according to the particular power applying agency se lected; for usew v ;While the invention is illustrated and described in a vform of: embodiment particularly eflicacious for solution of' problems arising in connection with' the operation of .throughdoors of railway cars, commonly of the swing" type, it will be apparent that the invention may be applied with equal efficacy to the operation of sliding doors, and to doors in other situations; also that portions of the disclosed invention may be employed independently of other portions, and that re-arrangements and modifications of"- parts are possible, and are intended to be em-i braced herein, insofar as they are within the spirit of the invention as herein defined.
Referring first to Fig. 1, the door H is shown as carryin two short shafts, l2 and l3, in vertical alignment along the axis of swing of the door; the lower shaft |3 being adapted to pivot" ina stationary bearing plate M at the floor level, while the upper shaft |2 receives the turning effort applied thereto by the selected one of three power applying agencies, namely, the fluid motor I6, the spring motor H, or the hand of the person desiring passage through the door way The determination of which agency is to be effective on any given occasion depends, first',p upon the setting of a three-position control switch 2|, and secondly, upon the availability of energizing power for the two motors l6 and H. The manner in which these two factors determine the functioning of the system will become apparent as the description progresses.
The motors Hi and H are illustrated as adapted to receive compressed air or other operating fluid from a common feed line 26, the feeding and exhausting of such fluid being under the control of a pair of valves 5|, 52-; the
former being spring-biased to a fluid feeding position and shiftable to a fluid exhaustingposition upon energization of solenoid winding 28, and the valve 52 being spring-biased to a fluid exhausting position and shiftable to a fluid feed-- ing position upon energization of solenoid winding 3|l. Two conduits 3|, 32 lead to motor "I6, and a'single conduit 33 leads to motor H; the motor l6 having two mechanically connected pistons 36, 31 reciprocable in connected cylinders 38', 39, respectively, andithe motor l1 having a.
motor and of the. connections between the two motors, which control arrangement operates to hold the spring motor I! in an idling position, so to speak, throughout periods of utilization of the fluid motor l6 exclusively; the spring motor; however, being instantly shiftable to working, relationship to the door whenever desired; by the mere act of reversing the settingof there-- mote control switch 2|; and: being also" auto'-- matically shiftable to said working relationship whenever, for any reason, fluid pressure is absent from the feed line 26.
This novel control arrangement includes the use oi the pressure feeding conduit 33, above described, to. maintain sufiici ent pressure against the piston 40 of the. motor [.1 to hold its spring fully compressed. throughout all periods of excIusive, control. by the fluid mOtOr l fi also the 1156 of a slotted. link 46 as part of the mechanical transmission between the. said piston 40 and the door shaft; t2; the length. of the slot. inlink 4.6 being. sufllcient to permit. a full stroke: of. the
pistons 38- and 3.1, under fluid power,.wi-thout. ex ertingany reverse. pressure on the pistonJDw-hich therefor remains in an idle" position; it being noted, however, that this idling relationship will automatically beconverted to aworking relationship whenever fluidpressure isremoved from linen,
The. application of pressure fluid to motors l6 and I1 is under the directionofa pair of solenoid valves 5t, 52,, and a delayed-action.53;: the solenoidwindings-n, 30 f. valves i 52-, and-the windin: of relay 53-beingsu-pplied with: current from a source 56, under the joint control of door latch switch 51 and the 'three-position control switch It, previously referredto. The multiple: operatI.-- ing possibilities areasfollows: 1 1
. QperdtiQn-Aiwpening; andclosing of; thedoor. by pcwer applied: to motor (Control switch 2| in Automatic position, bridging: contacts: 62, 13 (figs-,2 and 3') j With control switch- 2+ inthe Automatic" posi-- tion bridging, contacts I3, 62 aci-rcuitis completed from source to theiwi-nd-in of pressure magnet valve 52' to' d rect: pressure) fluid through thevalves 527and 51- in successionand-into cylin-' den, througl-rconduit s21, and-alsothroughcomduit 31 to-the working; chamber-between. the two I pistons 36, 3;! and at the same time through conduit as to motor 151,. thus.- placingthe. system in: condition for successive automatic-opening. and
closings movements of the? door: I i the doors-being now intheolosed position, as; e differential of pressureon pistons 36: and 31' is such; as .i-,o-hold:v said pistons in: their Y extreme leftward ,positionsi (See: Fig; .Moreoven, piston MS. of: motor Iii,
ig'held at its extremerrightward-'position (Fig; 2:)i by-reasorrof;the;pressure-fluidaentering themotor bywayofconduit-fi. 1
Let it be'supposedithatwitlr the parts; in the positions j-ustrindicated'.. at person desiring; pas-' otconductors' 63" and 64,; and its own normally-- bridged contacts and 66. Energization of the relay Winding, though only momentary, is sumcient to snap the bridging member 61 of the relay into bridging relationship to contacts 68 and 69, which bridging relationship continues for three, four, five, or more seconds, according to the adjustment, (not shown) of the delayed-action dashpot or other mechanism governing the return of bridging member 61 to its normal (non-bridging position).
During the continuance of this bridging relationship of'pa-rt 6''! to contacts 58, 69 current flows irom" source 56: to the winding 28 of exhaust magnetvalve. the path of flow being by way of said parts. 87;.68', 89, and conductor H. The result: of this activation of valve 5| is to exhaust pressure fluid from cylinder 39, by way of conduit 32', whereupon pistons 36, 31 move from left to right (the pressure on the left side of piston 31 being now dominant) and causes the door H to swing, fromthe closed position to the open position;
When thepre-set timedela-y has run its course (three ormore seconds member 6] drops away from contacts, 69, thus} tie-energizing exhaust magnet valve 5". Pressure fluid instantly reenters: the line;- 32 and the cylinder 39, to the right of piston:- 3fl, moving the piston assembly 36, 31' to the left andthus returning the door H toits closed position.
Operation B.-Causing the door to be held in the open position. (Control switch 2| in Re main @pen position, bridging? contacts 62, 1,3,. 14' (Flare),
When a train porter, or other person desires to. have the; door open, and: remain open for a period: of unmeasured. duration. the switch. 2|.
can-v be. thrown toxthe Remain- Open position,v
thus establishing; a circuit fromv source' 56 to the exhaust, valve magnet winding 28,, by way; of bridged contacts:'l3,. 14 of said switch 21.. As this: circuitmaintains the valve ii in a; positionxwhich continuously ventsrcylind'er 397130 the: atmosphere, by" way of, conduit.- 32 it. willube apparent that:
onset-the door" haszbeenf opened; (as, previously described): it; will remain. open because oi the absence of: any closing pressure. fluid in cylinder- 39'; the; piston: ottmoiibr l'l' beingconcurrently" held' in: its: inner position by the continuing pressure of the pressure 'flui'd acting against. said piston. 1
operaziovrdr-closingatne doorby power stored. in. the: spring motor if; (Control switch 2| in manual? opening" position, separating contacts .2 and from Hi. 'See Ftg. 5.
Placing control switch; It inxi'ts third position.
breaks the normally closed circuit. from source 55 w the winding: ac or pressure? magnet valve As? a: result of" this 'worliing stroke of piston 4'0 the door is moved back to the closed-position, automatically and without any'fluiif pressure assistance following any {opening I thereof menu--- ally; so long as switch 2 I remains this positionr.
The spring 4| will also functionas auto any absence: of: effective electric current, for i'n' either ofgthesezsituatious'tlrerewill be no metric-- tion on the free expansion of spring 4 I, following each compression thereof.
What we claim is:
1. Mechanism for operating a door comprising a cylinder and piston, said piston having less effective area on one face than on the other, a linkage connecting the piston to the door to cause motion of the piston to be transmitted to the door, to move the door in one direction or the other, according to the direction of motion of the piston, a source of fluid pressure, a pair of fluid conduits leading from said source to said cylinder, one conduit terminating in said cylinder on one side of said piston, and the other conduit terminating in said cylinder on the other side of said piston, a valve in one of said conduits, namely, the conduit leading to that end of the cylinder toward which faces that'side of the piston having the greater eifective area, said valve having fluid admitting and fluid-exhausting positions, means for shifting said valve to said fluid-exhausting position to cause the piston to move in the door-opening direction, and settable control means for (a) causing said valve to remain indefinitely in said fluid-exhausting position, following operation of said shifting means, or (b) to shift back to said fluid-admitting position after lapse of a predetermined time interval, measured in seconds, and thereby cause the door either (a) to remain in the open position indefinitely, or (b) to return to closed position at the end of the said time interval, accord ing to the setting selected for said settable control means.
2. Mechanism for operating a door comprising a cylinder and piston, said piston having less effective area on one face than on the other, a linkage connecting the piston to the door to cause motion of the piston to be transmitted to the door, to move the door in one direction or the other, according to the direction of motion of the piston, a source of fluid pressure, a pair of fluid conduits leading from said source to said cylinder, one conduit terminating in said cylinder on one side of said piston, and the other conduit terminating in said cylinder on the other side of said piston, a valve in one of said conduits, namely, the conduit leading to that end of the cylinder toward which faces that side of the piston having the greater effective area, said valve having fluidadmitting and fluid-exhausting positions, means for shifting said valve to said fluid-exhausting position, and settable control means for (a) causing said valve to remain indefinitely in said fluidexhausting position, following operation of said shifting means, or (b) to shift back to said fluid admitting position after lapse of a predetermined time interval, measured in seconds, and thereby cause the door either (a) to remain in the open position indefinitely, or (b) to return to closed position at the end of the said time interval, according to the setting selected for saidsettable control means; said valve shifting means including a source of electric energy, a solenoid whose plunger operates said valve, and a pair of parallel circuits from said source to said solenoid and said settable control means including a switch movable to close one or the other, alternatively, of said parallel circuits.
3. Mechanism as defined in claim 2, wherein one of said parallel circuits includes time-delay means operating to re-open the circuit within a measured interval following closure thereof.
4. Mechanism for operating a door comprising a cylinder and piston, said piston having less effective area on one face than on the other, a linkage connectingthe piston to the door to cause motion of the piston to be transmitted to the door, to move the door in one direction or the other, according to the direction of motion of the piston, a source of fluid pressure, a pair of fluid conduits leading from said source to said cylinder, one conduit terminating in said cylinder on one side of said piston, and the other conduit terminating in said cylinder on the other side of said piston, a valve in one of said conduits, namely, the conduit leading to that end of the cylinder toward which faces that side of the piston having the greater effective area, said valve having fluid-admitting and fluid-exhausting positions, electro-magnetic means for shifting said valve to said fluid-exhausting position, settable control means for (a) causing continuous energization of said electro-magnetic means, and thereby causing said valve to remain indefinitely in said fluid-exhausting position, following operation of said shifting means, or (b) causing only brief energization of said electro-magnetic means, according to the setting selected for said electro-magnetic means, and means for returning said valve to the fluid-admitting position following such brief energization of said electro-magnetic means.
JOHN H. VANDER VEER. CYRUS \V. BASSETT.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 977,270 Bussey Nov. 29, 1910 990,877 Hulme May 2, 1911 1,037,267 Knight Sept. 3, 1912 1,072,749 McElroy Sept. 9, 1913 1,277,000 Turner Aug. 27, 1918 1,326,228 Turner Dec. 30, 1919 1,431,986 Simmon Oct. 17, 1922 1,529,434 Hynes Mar. 10, 1925 1,564,885 Oakley Dec. 8, 1925 1,925,976 Bracken Sept. 5, 1933 1,935,968 Winkelmann Nov. 21, 1933 2,365,742 Brooks Dec. 26, 1944
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US27754A US2606022A (en) | 1948-05-18 | 1948-05-18 | Door operation and control |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US27754A US2606022A (en) | 1948-05-18 | 1948-05-18 | Door operation and control |
Publications (1)
Publication Number | Publication Date |
---|---|
US2606022A true US2606022A (en) | 1952-08-05 |
Family
ID=21839586
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US27754A Expired - Lifetime US2606022A (en) | 1948-05-18 | 1948-05-18 | Door operation and control |
Country Status (1)
Country | Link |
---|---|
US (1) | US2606022A (en) |
Cited By (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2710186A (en) * | 1948-07-21 | 1955-06-07 | Nat Pneumatic Co Inc | Door operation and control |
US2800323A (en) * | 1951-10-02 | 1957-07-23 | Pittsburgh Plate Glass Co | Door-operating system |
US2810571A (en) * | 1952-12-10 | 1957-10-22 | Paul R Ferguson | Door actuator |
US2852236A (en) * | 1956-12-28 | 1958-09-16 | Challenge Mfg Co | Laundry drier door |
US2911210A (en) * | 1955-11-25 | 1959-11-03 | Stanley Works | Hydraulic door operators |
US2913876A (en) * | 1953-03-09 | 1959-11-24 | Smiths Jacking Systems Ltd | Hydraulic jack systems |
DE1119148B (en) * | 1958-02-12 | 1961-12-07 | Elisabeth Zoeller Geb Kehl | Drive device for leaves of doors or the like with a pressurized piston-cylinder drive |
US3823510A (en) * | 1971-07-22 | 1974-07-16 | Sigma Tau Ind Farmaceuti | Automatically positionable gate assembly |
US4346533A (en) * | 1980-04-26 | 1982-08-31 | Gebr. Bode & Co. Gmbh | Drive for a vehicle door |
US4378656A (en) * | 1980-05-21 | 1983-04-05 | Firma Gebr. Bode & Co. Gmbh | Anti-clamping device for a vehicle door |
EP0422710A1 (en) * | 1989-10-13 | 1991-04-17 | FAAC S.p.A. | Bar gate device with symmetrical actuator |
US5282336A (en) * | 1992-10-19 | 1994-02-01 | Walt Tucker | Vehicle actuated fence gate |
GB2422405A (en) * | 2005-01-21 | 2006-07-26 | Access Automation Ltd | Ram actuated automated security gate |
US7364489B1 (en) | 2003-04-30 | 2008-04-29 | Hasbro, Inc. | Electromechanical toy |
US7431629B1 (en) | 2002-02-12 | 2008-10-07 | Hasbro, Inc. | Electromechanical toy |
US7695341B1 (en) * | 2002-11-27 | 2010-04-13 | Hasbro, Inc. | Electromechanical toy |
US10245517B2 (en) | 2017-03-27 | 2019-04-02 | Pacific Cycle, Llc | Interactive ride-on toy apparatus |
Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US977270A (en) * | 1910-05-24 | 1910-11-29 | Joseph Warren Bussey | Gate for cars. |
US990877A (en) * | 1910-10-06 | 1911-05-02 | John W Hulme | Automatic safety-lock for doors. |
US1037267A (en) * | 1911-07-18 | 1912-09-03 | Frank Knight | Door opening and closing mechanism. |
US1072749A (en) * | 1910-11-08 | 1913-09-09 | Cons Car Heating Co | Pressure-motor. |
US1277000A (en) * | 1917-05-14 | 1918-08-27 | Westinghouse Air Brake Co | Motor for door and step controllers. |
US1326228A (en) * | 1919-12-30 | A corpo | ||
US1431986A (en) * | 1920-07-19 | 1922-10-17 | Westinghouse Electric & Mfg Co | System of control |
US1529434A (en) * | 1923-07-30 | 1925-03-10 | Cons Car Heating Co | Electric door control |
US1564885A (en) * | 1925-12-08 | Heatingr comsany | ||
US1925976A (en) * | 1932-03-15 | 1933-09-05 | Lawrence B Burrow | Elevating and lowering mechanism |
US1935968A (en) * | 1931-09-28 | 1933-11-21 | Paul W Winkelmann | Window operating device |
US2365742A (en) * | 1941-10-15 | 1944-12-26 | Trico Products Corp | Window operator |
-
1948
- 1948-05-18 US US27754A patent/US2606022A/en not_active Expired - Lifetime
Patent Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1326228A (en) * | 1919-12-30 | A corpo | ||
US1564885A (en) * | 1925-12-08 | Heatingr comsany | ||
US977270A (en) * | 1910-05-24 | 1910-11-29 | Joseph Warren Bussey | Gate for cars. |
US990877A (en) * | 1910-10-06 | 1911-05-02 | John W Hulme | Automatic safety-lock for doors. |
US1072749A (en) * | 1910-11-08 | 1913-09-09 | Cons Car Heating Co | Pressure-motor. |
US1037267A (en) * | 1911-07-18 | 1912-09-03 | Frank Knight | Door opening and closing mechanism. |
US1277000A (en) * | 1917-05-14 | 1918-08-27 | Westinghouse Air Brake Co | Motor for door and step controllers. |
US1431986A (en) * | 1920-07-19 | 1922-10-17 | Westinghouse Electric & Mfg Co | System of control |
US1529434A (en) * | 1923-07-30 | 1925-03-10 | Cons Car Heating Co | Electric door control |
US1935968A (en) * | 1931-09-28 | 1933-11-21 | Paul W Winkelmann | Window operating device |
US1925976A (en) * | 1932-03-15 | 1933-09-05 | Lawrence B Burrow | Elevating and lowering mechanism |
US2365742A (en) * | 1941-10-15 | 1944-12-26 | Trico Products Corp | Window operator |
Cited By (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2710186A (en) * | 1948-07-21 | 1955-06-07 | Nat Pneumatic Co Inc | Door operation and control |
US2800323A (en) * | 1951-10-02 | 1957-07-23 | Pittsburgh Plate Glass Co | Door-operating system |
US2810571A (en) * | 1952-12-10 | 1957-10-22 | Paul R Ferguson | Door actuator |
US2913876A (en) * | 1953-03-09 | 1959-11-24 | Smiths Jacking Systems Ltd | Hydraulic jack systems |
US2911210A (en) * | 1955-11-25 | 1959-11-03 | Stanley Works | Hydraulic door operators |
US2852236A (en) * | 1956-12-28 | 1958-09-16 | Challenge Mfg Co | Laundry drier door |
DE1119148B (en) * | 1958-02-12 | 1961-12-07 | Elisabeth Zoeller Geb Kehl | Drive device for leaves of doors or the like with a pressurized piston-cylinder drive |
US3823510A (en) * | 1971-07-22 | 1974-07-16 | Sigma Tau Ind Farmaceuti | Automatically positionable gate assembly |
US4346533A (en) * | 1980-04-26 | 1982-08-31 | Gebr. Bode & Co. Gmbh | Drive for a vehicle door |
US4378656A (en) * | 1980-05-21 | 1983-04-05 | Firma Gebr. Bode & Co. Gmbh | Anti-clamping device for a vehicle door |
EP0422710A1 (en) * | 1989-10-13 | 1991-04-17 | FAAC S.p.A. | Bar gate device with symmetrical actuator |
US5282336A (en) * | 1992-10-19 | 1994-02-01 | Walt Tucker | Vehicle actuated fence gate |
US7431629B1 (en) | 2002-02-12 | 2008-10-07 | Hasbro, Inc. | Electromechanical toy |
US7507139B1 (en) | 2002-02-12 | 2009-03-24 | Hasbro, Inc. | Electromechanical toy |
US7695341B1 (en) * | 2002-11-27 | 2010-04-13 | Hasbro, Inc. | Electromechanical toy |
US7364489B1 (en) | 2003-04-30 | 2008-04-29 | Hasbro, Inc. | Electromechanical toy |
GB2422405A (en) * | 2005-01-21 | 2006-07-26 | Access Automation Ltd | Ram actuated automated security gate |
US10245517B2 (en) | 2017-03-27 | 2019-04-02 | Pacific Cycle, Llc | Interactive ride-on toy apparatus |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US2606022A (en) | Door operation and control | |
US2155642A (en) | Control for heating systems | |
US2545549A (en) | Safety control for machines | |
US2975875A (en) | Automatic clutch device | |
US2710186A (en) | Door operation and control | |
US2578894A (en) | Door operation and control | |
US2052929A (en) | Electrically operated fluid flow controlling mechanism | |
DE938749C (en) | Device for automatic slide adjustment in hot and cold air systems to influence rooms | |
US2039186A (en) | Hydraulic servomotor for train controllers and the like | |
US2800921A (en) | Power failure responsive cut-off valve system | |
US2220327A (en) | Control system | |
US2578909A (en) | Door operation and control | |
US2052795A (en) | Two-hand control system | |
US1574197A (en) | Door-engine control | |
DE660384C (en) | Cooling system with at least two compressors | |
US2952402A (en) | Air delivery apparatus | |
US2397937A (en) | Remote-control apparatus | |
GB340678A (en) | Improvements in & relating to hydraulic servo-motors | |
DE386315C (en) | Heating system for railroad cars | |
US1975138A (en) | Apparatus for fluid pressure regulation | |
US1968864A (en) | Pump controlling apparatus | |
GB698579A (en) | Dual-switch control means for starting machines | |
US2402933A (en) | Electromagnetic motor and circuit controls therefor | |
US2157327A (en) | Matrix molding machine | |
US2028768A (en) | Die press safety system |