US2574314A - Timing device - Google Patents

Description

T. R ARDEN TIMING DEVICE Nmn 6, 11951 Filed Feb. 26, 1948 INVENTORD Thunw Rolfirdem Patented Nov. 6, 1951 UNITED TIMING DEVICE Thomas R. Arden,'Danbury,' Conn, assignor to Bard-Parker Company, Inc., Danbury, Conn., a

corporation of New York Application February 26, 1948, Serial No. 11,200

6 Claims.

This invention relates to timing devices, and has particular reference to a timing device which is especially intended and designed to automatically stop the operation of model airplane engines to predetermine and limit the time periods during which the airplanes are powered in their flights. The present timer may, however,

readily be adapted to perform other timing purposes.

One reason for limiting the duration of powered flights of model airplanes is to avoid flying of the same long distances from their launching points and thereby becoming lost. More importantly, however, in model airplane contests, flights for records and the like, the airplanes usually are flown against time rather than against one another, and a basic factor in determining and comparing their performances is the time during which they are powered in flight. It is important, therefore, to provide a timing device by means of which the time during which model airplanes are powered in their flights may be predetermined very accurately.

Accordingly, one special and important object of the present invention is to provide a timing device which is thoroughly reliable in operation to predetermine accurately the length of time during which a model airplane is powered in its flight. a

' Another special and important object of the invention is to provide a timing device which may readily and easily be adjusted to vary the amount of time during which it operates toperform its function, thereby tov variably predetermine the time periods of events which it controls,;as,- for example, the time period during which amodel airplane is powered in its flight.-

Another special and important object of the invention is to provide a timing device which completes its operation with a quick action, whereby it is rendered very accurate in the performance of its timing purpose. I

In model airplanes, conservation of space and reduction in weight are important considerations. Accordingly, another object of the invention is to provide a timing device which may be quite small in size and of very light weight. a

The present timing deviceis designed to stop an engine by cutting off its fuel supply, and in this connection another object of the invention is to provide'a timing device which is designed to accomplish this purpose reliably and positively.

The'p'resent' timing device is, moreover, of the cylinder and piston, hydraulictype, andin this connection another object of the. invention is to provide a timing device of this type which utilizes as its liquid the fuel which it controls.

With'the foregoing and other objects in view, which will become more fully apparent as the nature of the invention is better understood, the same'consists of a timing device embodying the novel features of construction, combination, and arrangements of parts, as are illustrated by way of example in the accompanying drawings and as will be hereinafter more fully described and claimed. s

In the accompanying drawings, wherein like characters of reference denote corresponding parts in the different views:

Figure 1 is a central, longitudinal section through a timing device constructed in accord ance with the invention. 1

Figure 2 is an end view of the device; and

Figure 3 is a cross section on the line 33 of Figure 1.

Referring to the drawings in detail, it will be observed that the present timing device comprises a cylinder II] which is closed at one end by a head H and which has slidable therein a piston 12 which is urged constantly toward the head II by a spring [3. I i In the head II and extending transversely thereof is a fuel passageway M which, at one end, is provided with a nipple or other suitable fitting 15 for connection with a fuel supply line and which, at its other end, is in communication with a valve chamber IS in said head. I

A bore I! in the head I l provides communication between the fuel passageway I4 and the cylinder space a between said head I] and the piston l2 under the control of a check valve [8 which opens toward said cylinder space aand closes toward said fuel passageway. Thus, upon movement of the piston 12 in the cylinder [[0 away from the head ll, fuel will be drawn into the cylinder space a through the bore H, but will not escape from said cylinder space through said bore upon movement of said piston toward said head ll.

The valve l8 may appropriately be a ball, and a spring I9 preferably is provided to maintain it closed except when the piston I2 is moved away from the head II.

The piston I2 is intended to be moved manually away from thehead II and to that end is provided with a suitable handle 20 which may appropriately be in the form of a rod disposed in axial alignment with said piston and extending therefromthrough a guide opening in a 010- s reil; o th 5. 9i th s li l"; WmQW' P- the end thereof which is closed by the head II. In this connection, the spring I3 may appropriately be a helical expansion spring as shown and may be interposed between the piston I2 and the closure 2| so as to perform its function of urging said piston constantly toward the head I I.

In the head I I is a duct 22 which connects the cylinder space a with the fuel passageway I4 and which has associated therewith a suitable valve 23 for varying its effective cross sectional area.

As shown, said valve 23 may appropriately be of the needle type and may be threaded in the head II so that by rotation thereof its inner, pointed end may be moved into and from the duct '22 to vary the effective cross sectional area of the latter. A suitable handle 24 on said valve 23 exteriorly of the head I I affordsa convenient means for finger engagement to effect desired adjustments of said valve.

The valve chamber I6 extends longitudinally of the head II and at its inner end is connected with the cylinder space a by a port 25, while at its outer end it is provided with a suitable fitting 26 for connection with a part of the fuel supply line leadin to an engine.

In the valve chamber I6 is a valve member 21 of the spool type which, at its inner end, .is providedwith a'valve formation 28 for cooperation with a seat surrounding the portto control flow of fuel through said port, and which, at its :1

outer end, is provided with a second valve formation 29 for cooperation with a seat constituted by the inner end of the fitting 25, or'byany other suitable means, to control flow of fuel from the chamber I6 to said fitting 26.

The distance between the valve formations 28 and 29 is slightly less than the distance between the seats with which they cooperate. Consequently, when either of said valve formations is closed, the other is open. In this connection, a

suitable spring 30 tends constantly to move the valve member 21 inwardly and hence maintains the valve formation 29 normally closed and the valve formation 29 normally open.

Extending from the inner end of the valve member21 through the port 25 into the cylinder space a is a stem 3I which is engageable by the piston I2 just prior to said piston reaching its limit of movement toward the head -I-'I, so that by the final small amount of movement of said piston toward said head I I, the valve member-21 is moved positively outward and thereby the valve formation 28 is opened and the valve formation 29 is closed. In this connection, the

effective cross sectional area of the port 25 and the strength of the spring 30 are such, in relation to the strength of the spring I3, that the valve member 26 is not moved outwardly by the pressure generated in the cylindrical chamber a by said spring I3, but only by positive action of the piston I 2 against the-stem 3 I.

Suitable means, such as a laterally flexible spring arm 32 suitably fastened to the closure 2I and engageable in an annular channel 33 in the handle rod '20, is provided to releasably hold the piston I2 in a starting position spaced any suitable distance from the head II.

Assuming that the timer is interposed in an engine fuel supply line; that the cylinder space a. is devoid of fuel, and that the piston I2 is at .its limit of movement "toward the head II, it is apparent that by exerting a pulling force on the handle .rod 20 the piston will be moved away from thehead II 'and thereby fuel will be drawn freely into the cylinder space a. through the bore 4 I! from the fuel line constituted in part by the passageway means afforded by the passageway I4, the valve chamber I6 and the fitting 25. It will further be apparent that by pulling on the handle rod 28 until the channel 33 becomes alined with the spring arm 32 and the latter engages in said channel, a definite starting position of the piston I2 will 'be established and a definite amount of fuel will be contained in the cylinder space a.

Once the cylinder space a has been charged withfuel in the manner stated and the piston I2 is in its starting position, the spring arm 32 willactyby engagement with the channel 33, to maintain that condition indefinitely or, in other words, until the spring arm 32 is flexed from said channel 33 by finger pressure exerted against said arm. Thus the engine may be operated as long as desired prior to initiation of a predetermined time period of operation thereof by manual release of the spring-arm 32, since the normally open valve formation-29 will permit free flow of fuel from the source of supply to the engine.

Upon release of the spring arm 32, the spring I3 will act to urge the piston I2 toward the head I I and to force the fuel contained in the cylinder space a from said cylinder space. Since the checl: valve I8 will prevent flow from the cylinder space a through the bore I1, and the normally closed valve formation 28 of the valve member 21 will prevent flow of fuel from said cylinder space a into the valve chamber IS, the duct 22 obviously constitutes the only avenue for escape of fuel from said cylinder space a. The rate at which fuel may escape from the cylinder space a through the duct 22 determines the rate of movement of the piston I2 toward the head II by the spring I3 and hence determines the amount of time required for said piston to move from-its starting position to its position in which it contacts the stem 3| and opens the valve formation 28. The valve .23 constitutes .an adjustable means for varying the effective cross sectional area of the duct .22 and hence the rate of escape offuel therethrough from the cylinder space a. Accordingly, by adjusting said valve 23, the time required for the piston I2 to move from its starting position to its position in which it engages the stem 3| and opens the valve formation 28 may be variably predetermined.

When the piston I2 engages the stem 3| and opens the valve formation 28, fuel may escape freely from the cylinder space a through the port 25 and hence the final portion of the movement of the piston I2 toward the head I I is quite quick. When the valve formation 28 is opened the valve formation 29 is simultaneously closed, thereby cutting off the fuel supply to the engine and causing the same to stop. Obviously, the valve formation 29 will be maintained closed until the piston I2 again is manually moved outwardly relative to the head I I, whereupon :the spring 38 will act to shift the valve member 21 to close the valve formation 28 and open the valve formation 29-.

If desired, but not necessarily, a check valve 34 may be included in the outlet portion of the fuel line between the valve chamber I6 and the engine to prevent fuel from being withdrawn from this portion of the fuel line when the piston I2 is. moved outwardly relative to the head to charge the cylinderspace a with fuel. Appropriately, said check valve 34 may be incorporated in the fitting '26, as shown.

7,: v Obviously, the present timingtdevice mayyadvantageously be of very small sizeand light weight and possesses the further advantage that it utilizes the fuel which it, controls as the liquid medium for its hydraulic operation. It is, moreover, smooth and positive in operation and in itself constitutes a fuel reservoir so that the fuel tank may, if desired, be correspondingly reduced in size. It furthermore'acts, by subjecting the fuel in the fuel line to pressure, toinsure supply of fuel to the engine.

From the foregoing description considered in connection with the accompanying drawings, it is believed that the construction and operation of the'present timing device willbe clearly'understood and its advantages appreciated. It is desiredto point,out,, however, that while only a single, specific structural embodiment of the invention has been illustrated and described, the same is readily capable of specifically different structural embodiments within its spirit and scope as defined in the appended claims.

I claim:

1. A timing device comprising a cylinder, a head closing one end of said cylinder and having therein passageway means constituting part of a liquid supply line, a piston in said cylinder movable toward and away from said head, means for the free flow of liquid from said passageway means into said cylinder between said head and said piston when said piston is moved away from said head, spring means to move said piston toward said head, releasable means to hold said piston in a definite starting position spaced from said head, means providing two outlets for liquid from said cylinder to said passageway means, a spring biased valve maintaining one of said outlets closed against pressure generated in said cylinder by movement of said piston toward said head by said spring means, a valve adjustable to vary the eifective cross sectional area of the other of said outlets to regulate the rate of flow of liquid from said cylinder to said passageway means and thereby vary the time required for movement of said piston from its starting position a predetermined distance toward said head, means whereby said piston acts positively to open said spring-biased valve following a predetermined amount of movement of said piston toward said head thus to permit free flow of liquid from said cylinder to said passageway means and consequent quick movement of said piston during the final part of its movement toward said head, and other valve means operable by said piston during the final quick portion of its movement toward said head to close said passageway means against flow of liquid therethrough.

2. A timing device comprising a cylinder, a head closing one end of said cylinder and having therein passageway means constituting part of a liquid supply line, a piston in said cylinder movable toward and away from said head, means for the free fiow of liquid from said passageway I means into said cylinder between said head and said piston when said piston is moved away from said head, spring means to move said piston toward said head, releasable means to hold said piston in a definite starting position spaced from said head, means providing two outlets for liquid from said cylinder to said passageway means, a spring biased valve maintaining one of said outlets closed against pressure generated in said cylinder by movement of said piston toward said head by said spring means, a valve adjustable to vary the effective cross sectional area of the head,;and a normally open valve fixed with re-.

spect tosaid spring-biased valve and movable with-the latter during opening thereof to close said passageway means against flow of liquid therethrough.

3. A timing device comprising a cylinder, a head closing one end of said cylinder and having therein a liquid passageway and a valve chamber with which said passageway is connected, a piston in said cylinder movable toward and away from said head, spring means to move said piston toward said head, a check valve-controlled bore permitting free flow of liquid from said passageway to the cylinder space between said head and said piston and denying flow of liquid from said space to said passageway, releasable means to hold said piston in a definite starting position spaced from said head, a duct for flow of liquid from said cylinder space to said passageway, an adjustable valve to vary the rate of flow of liquid from said cylinder space through said duct to said passageway, said valve chamber being in communication with said cylinder space, said head having a liquid outlet communicating with said valve chamber and through the latter with said liquid passageway, a valve member in said valve chamber having two valve formations one controlling flow of liquid between said cylinder space and said valve chamber and the other controlling flow of liquid through said outlet, spring means effective to hold said first mentioned valve formation normally closed against the pressure generated in said cylinder space by movement of said piston toward said head by said first mentioned spring means and to hold said second mentioned valve formation normally open, and means whereby said piston acts positively during the final portion of its movement toward said head to shift said valve member to open said first mentioned valve formation and to close said second mentioned valve formation.

4. A timing device as set forth in claim 1, in which the passageway means includes an outlet portion to one side of the last mentioned valve means, having therein a check valve to prevent flow of liquid therethrough toward said second mentioned valve means.

5. A timing device designed to perform its timing function by cutting off flow of fluid through a conduit after the elapse of a predetermined period of time, said device including a fiuid conduit and a chamber, means providing for free flow of fluid from said conduit to said chamber and for throttled flow of fluid from said chamber to said conduit, a member movable outwardly in said chamber to increase its effective size and thus draw fluid into the same from said conduit, means operable in response to a predetemined amount of movement of said member into said chamber to provide for free flow of fluid from said chamber to said conduit and thus provide for quick movement thereafter of said member into said chamber, and means operable in response to said quick through said: conduit.

' 6 A' timingdevioe to out off the fuel supply to an 'en gine and thus" automaticallv stop the engine after the elapse of apr'edeternlined period of time, said'deviceincluding a chamber and means for connecting the same with an engine fuel supply conduit for free flow of fuel to the same from the conduit and for throttledfiow of fuel from the same to the conduit; a member movable outwardly in said chamber to increase its'efiective size and thus drawffuel into the same from said conduit, spring means for moving said member into said chamber 'to expel fuel therefrom into said conduit; a valve for controlling flow of fuel through the conduit, said valve being normally open, means operable in response movement of said member tocut off fiovv of to a predetermined amount of movement of said member into said chamber to provide for free flow of fuel from" said chamber 'to' said conduit and thus providefor quick movement thereafter 01' said member into said chamber, and means'op erable in response 'to said quick movement of said member to close said valve and'thus cut off flow of fuel through said conduit.

' THOMAS R. ARDEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Date

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