US2578992A

US2578992A - Electrosteam actuator

Info

Publication number: US2578992A
Application number: US780367A
Authority: US
Inventors: John W Dickey
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1947-10-17
Filing date: 1947-10-17
Publication date: 1951-12-18
Anticipated expiration: 1968-12-18

Description

De. 18, 1951 J. w. DICKEY 2,578,992

ELECTROSTEAMACTUATOR Filed Oct. 17, 1947 s Sheets-Sheet 1 IN V EN TOR.

. M1 1000 WITNESS zm.mz:+ k zxx AT ENE? Dec. 18, 1951 J. w. DICKEY 2 ELECTROSTEAM ACTUATOR Filed Oct. 1'7, 1947 3 Sheets-Sheet 3 IN V EN TOR.

WITNESS: U BY 5m. m7: %@M ITOHZVEY Patented Dec. 18, 1951 UNITED STATES ELECTROSTEAM ACTUATOR John W. Dickey, Newfield, N. Y., assignor to Bendix Aviation Corporation, a corporation of Delaware Application October 17, 1947, Serial No. 780,367

1 Claim. (01. 60- 25) The present invention relates to an electrosteam actuator and more particularly to a rectilinearly actuated jack or ram energized by internally generated steam. The present disclosure is in the nature of an improvement over the structure shown in applicants prior application, Serial No. 608,539, filed August 2 1945, now Patent No.

2,548,708, and incorporates novel and desirable features for controlling and utilizing the steam actuator, and for preventing it from generating excessive pressures or temperatures.

It is an object of thepresent invention to provide a novel electro-steam actuator incorporating devices for controlling and cushioning its operation.

It is another object to provide such a device incorporating means for storing up energy in the actuator and using it as an impulse driver or impeller.

' It is another object to provide such a device having pressure and temperature actuated elements for protecting the actuator from excessive stresses.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawings, in which: Fig. 1 is a vertical substantially mid-sectional view of one preferred embodiment of the invention. the electrical connections being shown diagrammatically;

Fig. 2 is a similar view of an embodiment of the invention incorporating means for cushioning and controlling the stroke of the actuator;

Fig. 3 is a detail in side elevation showing the thermostatic control for the electrical heating element shown in Fig. 2;

Fig. 4 is a further elevation on a reduced scale showing a pair of actuators such as illustrated in Fig. 2 used to operate a rotary shaft such as a window adjusting shaft;

Fig. 5 is a side view of the structure shown in Fig. 4;

Fig. 6 is a vertical substantially mid-sectional view of an embodiment of the invention in which the piston of the actuator is automatically caused to reciprocate continuously in order to perform thefunction of a pump;

Fig. 7 is a similar view of an embodiment of the invention adapted to be used as an impulse drive such as a starting device for internal combustion engines? and Fig. 8 is a section taken substantially on the line 8--8 of Fig. 7.

In Fig. 1 of the drawing, there is illustrated a cylinder I having a puddle 2 of vaporizable conductive liquid at its lower end with aheating element in the form of a perforated metallic disc 3 immersed in the liquid to supply electrical energy for vaporizing the liquid. A piston Al having a packing member 5 is slidably mounted in the cylinder and has a rod 6 suitably fixed thereon, which passes through an opening 1 in a closure plate 8 fixed as indicated at 9 to the upper end of the cylinder I.

The disc 3 is fixed in the lower end of the cylinder l by means of suitable insulating mounting members H), H and I2 and a clamping bolt (3 which serves as a binding post for the attachment of an electrical conductor.

Means for supplying electrical energy to the disc 3 is provided comprising power lines It and I5, the line I4 being connected to the binding post l3 through a manual switch it while the line I5 is grounded on a mounting bracket H for the cylinder L; The power lines are preferably connected to a source of alternating current as indi cated in order to prevent electrolytic action in the liquid.

Means for limiting the vapor pressure beneath the piston 4 Within the cylinder 1 is provided in the form of a safety valve comprising a spherical member IB which is heldseated by a spring 19 in the upper end of a passage 2| through the piston 4, whereby said passage is normally closed, but escape of steam through said passage is permitted when suflieient pressure is built up to over come the force of the spring 19. Vent 22 in the closure plate 8 permits passage of fluid above the piston l into and out of the upper end of the cylinder l.

The liquid 2 may be an aqueous solution of a suitable salt such as sodium sulphate, and the level of the liquid in the cylinder is preferably maintained above the piston 4 as shown, in order to provide a. reserve to replace evaporation, and to condense any steam which escapes by the safety valve IS. A layer of oil 20 on the surface of the liquid 2 may be used to retard evaporation.

In the operation of this embodiment of the invention, closure of the manual switch 16 completes the circuit from the power line M through the disc 3 and the vaporizable liquid 2 to the body of the cylinder l and back through the lead IS. The heat generated by the resistance of the liquid to the passage of the current therethrough causes violent ebullition, and the pressure of the steam so generated raises the piston 4 in cylinder l, whereby the piston rod 6 may be caused to actu ate any load connected thereto.

Ifthe load to be actuated by the piston rod 6 should stick or should exceed a predetermined value, the pressure in the lower end of the cylinder builds up until the spring 19 is overcome by the pressure on the valve member I6, whereupon said valve member rises and permits the excess pressure to be released. The steam which escapes by the safety valve l8 is condensed as it enters the cool body of liquid above the piston 4, and when the switch i6 is opened to allow the parts to return to idle position, this liquid can return to the bottom of the cylinder by passing around the cup-shaped piston packing 5. The return of the piston to idle position is preferably assisted by a spring 23.

In Fig. 2 of the drawing, there is illustrated a cylinder 25 in which is slidably mounted a piston 26 similar to that shown in Fig l. The lower end of the cylinder contains a vaporizing liquid 21, and an electrical heating device 28 for vaporizing the'liquid is mounted in the lower end of the cylinder, insulated therefrom as illustrated at 29 and held in position by a clamping bolt 3| which provides an attachment for an electrical feed wire 32.

In this embodiment of the invention, the heater 28 comprises a resistance wire of suitable material adapted to be heated by the passage of current and means for heating the wire is provided comprising a battery 33 grounded at 34 and connected through a manual switch 35 to a feed wire 36. Wire 36 is connected to a movable contact 31 which normally engages'a fixed contact 38 to which a lead 39 is connected.

Means for

opening contacts

31, 38 as the piston 26 approaches the end of its stroke are provided comprising a flange member 4| fixed on a rod 42 attached to the piston, and a plunger 43 slidably mounted in a closure plate 44 in position to

open contacts

31, 38 when actuated by engagement of flange member 4|. The closure plate 44 is fixed as indicated at 49 to the cylinder 25, and serves as mounting means for

contacts

31, 38 which are supported thereon while being insulated therefrom as indicated at 45. The closure plate also serves as a guide for the piston rod 42. Means for deenergizing the electrical heating element 28 when the temperature ,of the cylinder 25 rises above a predetermined value is provided in the form of thermostatically controlled contacts 46, 41 best shown in Fig. 3. These contacts are mounted on a ring 48 clamped around the lower end of the cylinder 25 by a bolt 49 and insulated from the cylinder by a sleeve Contact 41, which is mounted on the clamping bolt 49, is connected to the electrical conductor 39, while contact 46 is mounted on a strip of bimetal 52,

which is connected to the heater lead 32, and is so tensioned as to maintain the contacts in engagement until a predetermined temperature is exceeded, upon which event the contacts are separated and the heater is thus deenergized.

In this embodiment of the invention, means are provided for preventing sudden motion of the piston 26 such as might be caused if the load should stick and should then be suddenly rethereby effectively preventing sudden or rapid movement of the piston. A spring 50 is provided for urging the piston toward its idle position.

In the operation of this embodiment of the invention, closure of manual switch 35 energizes the heater 29 since

contacts

31, 33 and contacts 46, 41 are normally closed. The consequent heating and vaporization of the liquid 21 .in the bottom of the cylinder generates steam pressure which causes the piston 26 to move upward, aotuating the rod 42 until the flange member 4| engages the plunger 43 whereupon the heating circuit is broken by the opening of

contacts

31, 36, and the generation of steam is interrupted. If

for any reason the liquid in the lower end of the cylinder should runlow, or pressure therein become excessive so as to raise the temperature of the lower end of the cylinder above a predetermined value, the thermostatic contacts 46, 41 open and break the heating circuit.

In Figs. 4 and 5, there is illustrated an application of the actuator shown in'Figs. 2 and '3 to operate a rotary shaft such as an adjusting shaft for automobile windows and the like. As there shown, two

such units

55 and 56 operate

piston rods

51, 58 having a lost-motion connection to an arcuate rack member 59 which meshes with a. pinion 6| on a windov adjusting shaft 62. A two' throw switch 63 is airanged to alternatively en-. ergize the

units

55, 56, one such unit 55 serving to move the rack 59 in the direction to raise the window as by means of an abutment 64 mounted on the piston rod 51 while the other unit' 56 serves to move the window toward closed position, as by means of an abutment 64 on the pisg tonrod 58.

In Fig. 6 of the drawing, there is illustrated an electrosteam actuator having means to cause continuous reciprocation of the piston so that the device may be used as a pump. As there shown, a cylinder 65 has a piston 66 slidably mounted therein and arranged to be actuated by steam generated by an electrical heater 68 from a vaporizable fluid 61 in the lower end of the cylinder. Heater 68 is clamped in the lower end of the cylinder 65 by a binding post bolt 69 connected to one end of the heater coil, the opposite end of which is grounded to the cylinder. Means for energizing the heater are provided comprising power leads 1|, 12, the lead 1| being grounded on the cylinder as indicated at 13 while the lead 12 is connected to a contact 14 mounted on alever 15 which is pivoted at 16 so as to rock about a horizontal axis. Contact 14 is insulated from the lever as shown at 11 and isarranged to engage a contact 18 mounted on a bracket 19 but insulated therefrom as indicated at 8|, and connected by a lead 82 to the binding post 69.

A pair of

permanent magnets

83 and 84 are mounted at the ends of lever 15 so that the rocking movement of the lever conveys them alternately into and out of engagement with the exterior of cylinder 65. Cylinder 65 is formed of non-magnetic material while the piston 66 is composed of magnetic material, such as soft iron. Consequently, as the piston approaches the ends of its stroke, the mutual attraction of the magnets and piston actuates the lever 15 to open the contacts at the upper end of the piston stroke, and close them at the lower end of the stroke.

A spring 85 is provided for urging the piston toward its. lower or idle position, the spring being confined in the'cylinder by aclosure plate 86 fixed as indicated at 81 to the upper end of- 5 the cylinder. An inlet fitting 80 having an intake check valve 89 and an outlet fitting 9| havingan outlet check valve 92 are mountedonthe closure plate 86 and connected to the pipe systernstlrrough which liquid is to be circulated by th pump.

In the operation of this structure, upon the application of the electrical energy to the leads II, I2 by and suitable manual control, since the contacts I4, I6 are closed when the piston is in its idle position/the heater 68 will be energized so as to vaporize the liquid 61 beneath the piston 66 and cause the piston to move upward and eject the liquid above the piston through the outlet fitting 91.

When the piston reaches the upper end of its stroke, it comes into proximity to the fixed magnet 83 which is accordingly attracted thereby so as to open contacts 14, 18. The heater 68 is thus deenergized and the piston is permitted to return to its lower position under the action of spring 85, drawing after it a new charge of liquid through the inlet fitting 88. As soon as the piston 66 comes opposite the permanent magnet 84, the latter is attracted by the piston so as to rock the lever I6 in a clockwise direction and close contacts I4, I8 whereupon the operation is repeated.

In Figs. 7 and 8 of the drawing, there is illustrated an embodiment of the invention which is arranged as an impulse actuator for purposes such as the starting of internal combustion engines. As there shown, a cylinder 93 has a piston 94 slidably mounted therein for actuation by steam generated from a liquid 95 in the bottom of the cylinder under the action of a heater 9'6 fixed therein by means of a binding post 91. Means for energizing the heater are provided comprising battery 98 grounded at 99 and connected by a manual switch I M and lead I02 to a movable contact I03 on an elastic blade I mounted on a closure plate I04 on the cylinder but insulated therefrom as indicated at I05. A cooperating fixed contact I 06 is also mounted on the closure plate I04 and connected by a lead I07 to the binding post 91 which latter is connected to one end of the heater 96. The opposite end of the heater is grounded on the cylinder as indicated at I08, and the frame of the device is grounded as indicated at I09 to complete the heater circuit.

A piston rod III in the form of a rack bar is fixed to the piston 94 and is guided for reciprocating movement in an opening H2 in the closure plate I04 which conforms closely to said rack. The rack III is formed with teeth II3 arranged to engage and rotate a pinion I I4 journalled in a plate II5 (Fig. 8) mounted on the closure plate I04. The spaces between the teeth II3 of the rack bar III permit the escape of air from the upper end of the cylinder through the opening I I2 without substantial obstruction. The teeth II3, however, terminate a substantial distance above the piston 94, leaving a solid portion of the rack bar III as indicated at I I0. This portion of the rack bar substantially fits the opening II2 whereby the escape of air from the cylinder is restricted as the piston 94 approaches the upper end of its stroke, thereby forming an elastic cushion for the reciprocating parts. A driving clutch member H6 is splined within the pinion I I 4 and provided with inclined teeth II I arranged to cooperate with similar teeth II8 formed in a driven clutch member II9 which may be formed-on or attached to the extended crank shaft of the engine to be started.

The clutch teeth H1, H8 are yieldably held in engagement by a compression spring I120 mount ed Within the pinion I I4 acting on clutch member II6.

Means are provided for yieldably obstructing the movement of the piston 94 and rack I I I away from'its idle position in order to build up considerable pressure in the lower end of the cylinder prior to the engagement of the rack with the pinion H4 so as to cause said pinion to be actuated energetically as an impulse starter. For this purpose, the upper end of the rack bar III is beveled as shown at I2I, and a roller detent member I22 which is slidably mounted in bracketsl I23 and I24 is yieldably maintained in the path of the rack bar and in: engagement with the beveled surface I2I by springs I25, I26. The brackets I23, I24 are arranged to permit the roller I22 to move out of the path of the rack bar III after the rack bar has exerted suflicient force thereon to cam the roller backward against the action of the springs I25, I26, after which the roller presents substantially no resistance to the further movement of the rack.

The contact-carrying blade I 00 is positioned in the path of movement of the detent member I22 whereby contacts I03, I96 are opened when the detent roller is cammed out of the path of the rack bar I I I, and are held open until the rack bar and detent return to their idle positions.

In operation, starting with the parts in the positions illustrated, closure of the manual switch IOI causes energization of the heater 96 whereupon the liquid is vaporized and steam pressure built up beneath the piston 94. When this pressure becomes sufficient to cause the inclined surface I2I of the rack bar to cam the detent roller I 22 out of the path of the rack bar, the rack is projected forcibly into engagement with the pinion H4, and the latter caused to transmit its rotation through the clutch I I1, I I8 to the engine shaft II9. When the piston approaches the end of its upward stroke, the solid portion III] of the rack bar enter the opening I I2, thus nearly closing said opening. The air trapped in the upper end of the cylinder consequently forms a cushion which yieldingly retards the movement of the piston rod and piston.

When the rack bar III cams the detent I22 out of its path, the contacts I03, I06 are opened, thus deenergizing the heater 96 and permitting the piston 94 t return to idle position under the influence of the spring I30. If the engine has not started, and the operator keeps the starting switch IOI closed, the heater 96 is immediately reenergized and the actuation of the starter repeated.

When the engine starts, the engine shaft II 9 overruns the clutch member II6 until such time as the rack member II I is returned to idle position, whereupon the pinion II 4 is permitted to rotate freely with the engine crank shaft.

Although certain embodiments of the invention have been shown and described in detail, it will be understood that other embodiments are possible and various changes may be made in the construction and arrangement of the parts without departing from the spirit of the invention.

I claim:

In an electro steam actuator, a cylinder and a piston slidably mounted therein, a puddle of vaporizable liquid in one end of the cylinder, yielding means urging the piston toward said end of the cylinder, an electrical heater adapted when 7 energized to form a flash boilerfor said puddle of liquid and thereby generate steam pressure between the piston and said end of the cylinder, and means actuated by the consequent movement of the piston for deenergizing the electrical heater, including further means for arresting the movement of the piston by said steam pressure comprising a fluid trapped in the cylinder back of the piston and a vent for said fluid; in which said trapped fluid is a liquid, and including further a storage chamber for the liquid ejected by the piston through said vent.

*i g JOHN W. DICKEY.

- REFERENCES CITED The following references are of record in the file'of this patent;

Number Number 8 UNITED STATES PATENTS Name Date Dodds June 26, 1900 Hall Aug. 30, 1904 Nathan May 1, 1917 Hill Sept. 4, 1928 Smith Oct. 28, 1930 Persons May 3, 1932 Procofieff-Seversky 1 June 19, 1934 Souter July 21, 1942 FOREIGN PATENTS Country Date France Oct. 11, 1921 Germany Sept. 13, 1933 Germany June 6, 1936