US2441402A - Automatic timer - Google Patents

Description

y 1943- J. EDELEN 2,441,402

AUTOMATIC TIMER Filed March 25, 1944 Patented May 11, 1948 AUTOMATIC TIMER James L. Edelen, Kirkwood, Mo., assignor to Carter Carburetor Corporation, St. Louis, Mo., a corporation of Delaware Application March 23, 1944, Serial No. 527,853

Claims. 1

This invention relates to timing devices and consists particularly in a novel apparatus of this type for use in connection with a fluid fiow measuring machine to operate a flow controlling valve.

Machines of this type have been used in calibrating and testing carburetors for internal combustion engines. The operators of such flow machines customarily, calculate with the aid of a watch, the quantity of fuel consumed during a period of time. The flow from the measuring device is started and stopped manually so that the attention of the operator is divided between the timing instrument, the shut-off valve, and the carburetor itself.

It is an object of the present invention to provide a timing device which operates wholly automatically, once it is set in motion, to open the flow controlling valve and hold it open for the exact time desired.

A more detailed object is to provide a timing device in which the mechanism is initially set in motion by the operator, but thereafter performs the timed operation and shuts itself oil wholly automatically.

These objects and other more detailed objects hereafter appearing are attained by the device illustrated in the accompanying drawing in which:

Fig. 1 is a diagrammatic view of a carburetor flow machine with the novel timing device applied thereto.

Fig. 2 is a perspective view of the timing device on an enlarged scale.

Fig. 3 is a sectional view of the gasoline flow controlling valve. I

Fig. 4 is a similar view with the valve in a different position.

Fig. 5 is a view of a detail in Fig. 2 and is taken substantially on line 55 of Fig. 2.

The flow machine illustrated in Fig. 1 comprises a suction pump I0 operated by an electric motor H and connected by a pipe I! to a vacuum box l3. A carburetor I4 is shown mounted on top of box 13. The depression in the box, which is effective to draw air and fuel downwardly through the carburetor barrel, is measured by a manometer associated with a scale iii. A practical form of manometer for this purpose is illustrated in my co-pending application, Serial No. 615,688, filed January 1, 1944. The carburetor is connected by a tube IT to an elevated constant level chamber 18 which, in turn, is connected by a tube 19 either to a fuel pump or gravity fuel feed.

A T-fitting 20 is interposed in tube I1 and mounts a vertical burette 2|. A barrel valve is mounted in T 20 and is controlled by an arm 26 to which is connected the core 21 of a solenoid 28. A return spring 29 constantly urges the valve to the normal position of Fig. 3.

The timing device is mounted on a substantial plate 30 having an angle bracket 3| projecting 'rearwardly therefrom. An electric motor 32, mounted on the front face of plate 30, has its shaft 33 projecting through the plate and rigidly attached to a driving cam 34. A shaft 35 is journalled between plate 30 and bracket 3| parallel to the motor shaft and rotatably receives first and second control cams 3'6 and 31 having alternate high and low peripheral surfaces, as shown.

Cam 31 has ratchet teeth 39 formed thereon adjacent a hand lever 40 which is loosely received on shaft 35. Lever 40 carries a pivoted detent 4i urged by its own weight against teeth 39 to form a ratchet. Lever 40 and cam 31 are urged rightwardly by a coiled, compression spring 42 compressed between bracket 3| and the lever. Teeth 43 on the abutting faces of cams 36 and 31 form a one-way, ratchet connection therebetween.

A set of ratchet teeth 45 are formed on the other control cam 36adjacent an angular lever 46 loosely received on shaft 35. A spring lip 41 engages these teeth to prevent counterclockwise rotation of the cam. Lever 46 mounts a pivoted detent 48 yieldingly held in ratchet engagement with teeth 45 by a spring strip 49. A coiled spring 50 is connected between a lug 5| on plate 30 and an extension 52 on lever 46 for constantly urging this lever clockwise.

Lever 46 also has a finger 53 constantly urged against the periphery of driver cam 34 by spring 50. The contour of driver cam 34 is such that during one revolution thereof, from the position shown in Fig. 2, lever 46 is rotated counterclockwise to cause pivoted detent 48 to clear one of the teeth 45. Finger 53 is then dropped to the low point of cam 34 to permit spring 50 to rotate lever 46 and control cam 36, through teeth 45 and detent 48, one step in the clockwise direction. By means of the meshing teeth 43, this motion of cam 36 is also transmitted to control cam 31.

Mounted in bracket 3|, below cams 36 and 31, are cam followers 54 and 55 which actuate switches 56 and 51, respectively, connected to and controlling solenoid 28 and motor 32. The electrical switch connections are conventional and, it is believed, will be clearly understood from the diagram in Fig. 1. These switches are held 3 normally open by springs, diagrammatically shown at 58 and 59.

The contour of cam 36 is such that switch 55 controlled thereby is alternately closed and opened at successive rotational steps of the cam, each produced by one cycle of driving cam 34. The contour of cam 31 is such that switch controlled" thereby is maintainedv closed during two steps of rotation thereof, as produced by two cycles of drive cam 34, and then opened for one step.

This device operates as follows:

To initiate the timing operation, the operator rotates lever 40 clockwise which, through detent 4| and teeth 39, rotates camST clockwise one stepso as to close switch 51 and start motor 32. Thereupon, rotation of drive cam 34 operates lever 46.

and detent 48 to rotate cam 36 one step. Solenoid switch 56 is then closed, causing valve arm 2-6 tobe rotated counterclockwise and valve 25 to be turned to the npositionsh'owninFig. 4. Liquid in burette 21 is then fedithroughithe tube I! and the carburetor. Since the high. points on cam 31 are relatively. wide, motor switch 51 is maintained closedfor a secondcycle of driving cam" 34. At the end of this cycle, lever 45. and detent 48 are operated by. spring, 50 to-rotate cam 35 another stepandbring a low point thereon opposite solenoid: switch actuator 54 and open this switch. Thereupon, solenoid: plunger 21 is released. and spring 29 returns-va1ve25to the position in Fig. 3 closing, the connection between the burette and carburetor and opening the buretteto elevated fuel chamber l8.-f.or'refilling ofthe'burette; Coincidentally, or slightly thereafter, a low point on cam 31 moves opposite motor switch actuator 55 so that switch 51 is opened and the motor is stopped.

Initiation of the-timing operation by lever 40, is effected independently of earns 36 and 34 because of spring-42-whichpermits ratchet teeth 43 to ride apart. Thedriving motor is maintained in operation automatically for exactly one complete timing periodwhichzis measured bytwo steps of cam 31; regardless'of the'stopping position of drive cam 34. Timing ofthe liquid fuel discharge from. the burette is, thus, effected with a minimum of attention fronrthe operator, who may observe the-functioning of thecarburetor or the manometer. Moreoventhe time element inhis calculation remains constant automatically.

The invention is particularly adapted for use with a portable flow machinesuch as illustrated in my co-pending application mentioned above, but is adaptable to other timed operations where its inherent function may be advantageous.- The device may be modified in. various-respects as will occur to those skilled in the art and-the exclusive useof all modificationsas come within the scope of the appended claims is contemplated.

I claim:

1. A control device-for a timed operation com.- prlsing'a driving member capable of rotation at uniform speed, a pair of controls, respectively, for'a timed operation andsaid member, a pair of cams'and cam followers, respectively, for actuating said controls; means operatively connecting said driving member'andisaid cams for joint; step by step actuation of' said cams, and means to in-- dependently actuate one of 'said cams to start said driving member; said last-mentioned cam being shaped to maintain said driving member in operation between two succeeding steps and to stop said driving member at the third step and the other cam being shaped to actuate its control at each step to alternately start and stop the timed operation.

2. A timing device comprising a driving member capable of operation at uniform speed, first and second-cams and followers therefor for controlling, respectively, a timed operation and said driving member, means operatively connecting said member and said first cam for step by step rotation of the latter by said member, a one-way, operative connection'between said cams for joint rotation thereof by said member, and means to independently. rotate said second cam, step by step,,said second cam being shaped to start said driving member upon rotation thereof through one step from its normal stopping position and to maintain said member in operation through the next step, and to stop said member at the third step, and saidfirst cam being shaped to alternately start and stop the timed operation at succeeding steps whereby accurate timing of the controlled operation is obtained upon initial actuation of said second cam.

3. A timing device as described in claim 2 in which said driving member comprisesa cam having a one-way, ratchet connection to said first control cam arranged to rotate said first cam one step during each cycle of said member.

4. A timing device asdescribed in claim. Zlurther including manual means to rotate said second control camindependentl of said first cam and said driving member to start thetiming cycle, said second cam being: automatically rotated thereafter by said driving member to stopthe timing cycle.

5. A timing control device comprising a motor capable of operation at a uniform speed, a control switch therefona driven shaft, a first and a second control cam rotatablev on said shaft, followers for said cams: for controlling, respectively, a timed operation and said switch, a step by step, operative connection between said motor andsaid first cam, a one way operative connection be-- tween said first. and second cams foreffecting joint rotation-thereofinone direction by'said motor, and manual means to rotate said second cam, independently, tostart said motor, said second cam being shaped to-close said switch during: two succeeding steps of said shaft andv to. open said switch at the thirdsucceeding step, andlsaid first cam being shaped to alternately start,.stop, and restart the timed operation during succeeding steps whereby a uniformly timed operation will be insured upon initial manual movement of' said second cam.

JAMES L. EDELEN.

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

UNITED STATES PATENTS.

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