US2485540A - Apparatus for illustrating economic laws - Google Patents

Description

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l' AYPARATUsgFoR ILLUSTRATING ECONOMIC L'Aws Filed May 22, 1947 @sheets-sheet 4 Patented Oct. 18, 1949 OFFICE APPARATUS FOR ILLUSTRATING ECONOMIC LAWS James D. Mooney, Oyster Bay, N. Y. Application May 22, 1947, Serial No..749,645

2 Claims.

This invention relates to improvements in apparatus designed to illustrate the laws oi economics by physical analogies. Apparatus of this type were set forth in my U. S. Letters Patent Nos. 1,989,878 and 2,281,368. The object of the present invention is to provide improved means for giving the mind physical pictures to aid in grasping abstract conceptions.

While in my earlier inventions the various mechanical actions representing economic forces were usually set into motion by means of manually operated controls, the demonstrations are made vastly more effective and convincing by providing suitable mechanisms Which automatically vary the physical factors and thus give a continuous and automatic representation of the interplay and interaction of economic forces.

The subject chosen for illustration in the present invention is the series of interrelated forces and reactions pertaining to supply, demand and price; the all-embracing name commonly used for these relations being The Law of Supply and Demand. Included in this so-called laW are the facts that:

(1) Prices depend upon supply and demand. They tend to rise if supply decreases or if demand increases. Conversely, they tend to fall if supply increases and de mand decreases.

(2) Supply and demand are aiected by prices. High prices tend to cause an increase in supply and a decrease in demand. Conversely, low prices tend to cause a decrease in supply and an increase in demand.

In the form of construction shown in my earlier patents, there was no automatic control of the ow of liquid representing Supply to correct variations in price. In actual business, an increase in price increases prots and stimulates production. It is highly desirable, therefore, that apparatus designed to represent business cycles and economic laws indicates such a relas tionship.

A further deiiciency in the mode of operation of the earlier forms'of my apparatus was the fact 2 demand created by the low prices acquires suflicient momentum to reduce inventories to the point at Which there becomes an acute shortage. There is then a quick reaction which carries prices abovetheir stable or average value. In general, 4demand keeps up longer than it should to bring inventories down and prices up to their proper levels. Supply likewise tends to keep up longer than it should Vto bring inventories up and prices down to their proper levels.

According to the present invention, therefore, valves are provided in both the Supply and Demand lines which are automatically opened wider and closed further by the rise and fall of the Inventory receptacle (i. e., price changes). When the latter sinks, indicating an increase in inventories and a corresponding decrease in price, the Supply valvey is closed further and the Demand valve is opened Wider so that the over-stocked and under-priced condition is rapidly corrected. When the' Inventory receptacle rises, the reverse takes place. The actual distance the Inventory receptacle rises and falls is not very great," soit is not always readily apparent When it stops moving in one direction preparatory to moving in the other.

Another object of the invention, therefore, is to provide a means for giving visual indication of whether or not the receptacle is moving and, if so, in which direction it is moving.

The present invention covers the mechanisms employed to portray, by graphic analogy, the above economic actions and reactions. Basically, the mechanism comprises:

(a) A receptacle containing a variable amountl of liquid representing the stocks or inventories of vgoods available on the market.

(b) Means for introducing into this receptacle a stream of liquid representing the supply of goods for sale on the market.

c) Means fordrawing from the receptacle a stream of liquid representing the demand for goods at the'prevailing market price.

(d) A float which supports the Inventory receptacle and rises and falls as the amount of liquid in such receptacle decreases and increases.

(e)r Various mechanisms and devices for automatically and/or manually varying and controlling the rates of flow of the Supply and Demand streams in various manners aimed to illustrate by analogy the interactions of economic forces in true life.

Conveniently, such mechanisms and devices include electric motors Wound for operation in eitherdirection. These Amotors open or close valves in the Supply" and Demand pipes according to the direction o'f flow of electric current through such motors. The supply of current to such motors is controlled by a series of switches opened and closed by vertical movements of the oat produced by changes in the amount of liquid in the Inventory receptacle.

Operation of the apparatus is as follow-s: Water is forced by a centrifugal pump through a pipe and valve to a header on the Supply shelf. As the pump is of the centrifugal type, the quantity of liquid it delivers may be controlled by a valve in its delivery pipe. The valve in the Supply line is motor-driven and is actuated in the proper manner in accordance with impulses originating from and dependng upon the prevailing conditions of Pricef The mechanical and electrical arrangements are such that, in general:

(a) The Supply valve tends to open when the Price is high.

(b) The Supply valve tends to close when the "Price is low.

The liquid, after pouring from the Supply header and chute, flows into the Inventory receptacle. It then flows, by force of gravity, from the receptacle by way of the Demand pipe. Such gravity flow is dependent on the head of liquid in the receptacle.

It has been found desirable to accentuate the effect of gravity by a Demand valve in this pipe line. The valve is motor-driven and the mechanical and electrical arrangements are such that, in general:

(a) The Demand valve tends to open when the Price is low (i. e. when the amount of liquid in the receptacle is large).

(b) The Demand valve tends to close when the Price is high (i. e. when the amount of liquid in the receptacle is small).

After flowing from the Demand pipe, the liquid finds its way back to the reservoir from which it is again circulated through the same cycle.

The rise and fall of price are represented by the rising and falling motion of a float which supports the dead weight of the Inventory receptacle. When a large amount of liquid iills the receptacle, representing large inventories of goods, the weight in the receptacle causes the iloat to sink deeply in its supporting iiuid, this action typifying falling prices. Conversely, when the Inventory receptacle is nearly empty, representing a condition of scarcity of goods available for sale, the float supporting the re ceptacle rises, typifying rising prices.

Various means may be employed for opening and/or closing the Supply and Demand valves as the receptacle moves up and down. Preferably such means include mechanical connections to the oat for actuating cam surfaces which can be pre-set to operate electrical switches which will energize the valve-operating motors in accordance with predetermined patterns. In this manner the conditions and variations pertaining to Price can be made to cause the streams of Supply and Demand" to respond in the correct manner.

As an auxiliary and manual means for controlling the actions of the valves-as when it is desired to demonstrate some particular economic phenomenon-a system of manually operated electrical push buttons may be provided. One suitable arrangement comprises six push buttons: three for Supply and three for Demanc In each set of three one button causes the actuatingl motor to increase the Valve opening, another to decrease it, while the third renders the motor inoperative in the event it is desired to demonstrate the effects of blocking or interfering with certain economic forces.

The electrical circuits are so arranged that the push buttons take precedence in operation over the cam-operated switches.

It is also advantageous to provide overtravel limit switches to prevent the motor from driving the valves beyond limits where mechanical damage might be incurred. They also perform the function of making it possible to pre-select the maximum and minimum degrees of valve openings beyond which the valves should not travel for the most eiective presentation.

One suitable form of construction is illustrated, by way of example, in the accompanying drawings, wherein:

Fig. l is a front elevation of the apparatus as a whole;

Fig. 2 is a diagrammatic front elevation of the apparatus showing the liquid circulation means;

Fig. 3 shows the wiring diagram for the valveactuating motors;

Fig. 4 is a more or less diagrammatic view of the oat, Inventory receptacle and the mechanism and switches operated by movements of the former;

Fig. 5 is a plan view of the push button panel;

Fig. 6 is a diagram showing the ranges over which the various motor-controlling switches are operative;

Fig. '7 is a detail view on an enlarged scale of part of the mechanism shown in Fig. 4; and

Fig. 8 is a section on the line 8-8 of Fig. 4.

The apparatus illustrated comprises a cabinet I0 having a wall II extending upwardly from its rear side. This cabinet performs a dual function; rst it acts as a support for parts of the apparatus, such as the Stable money tank I2 and the Demand distributor I3, and second it serves as a housing for the waterreservoir I4, pump I5 and motor IS.

The liquid circulating system is shown in Fig. 2. Water is forced by pump I5 through pipe I1, valve I8 to a header IS on the Supply shelf 20. From the header I9 is a series of outlets 24, three as shown. Adjacent to the first of these are miniature gures and models representing the delivery of b arrels and packing cases containing manufactured goods. Over the second is the representation of an oil derrick as symbolic of natural mineral products. Adjacent the third is a farm wagon to indicate the supply of wheat, cotton and other farm products.

Water discharged from these outlets flows forwardly over the shelf and down its front where an inclined trough 25 collects the Water from all three outlets and discharges it as a single stream through a spout 26. Beneath this spout is an Inventories receptacle 21 of glass or other transparent material mounted on top of the float 28 in the tank I2. From the bottom of receptacle 21 extends a pipe 28a for discharging water into the Demand distributor I3.

The Demand distributor consists of a cylinder 33 from which lead a series of outlet pipes 34. These pipes discharge into a series of downcasts 35, the lower ends of which are above the level of the water in the reservoir I4. Around the downcasts is the representation of a retail ,-oat'for various reasons. enables the distance between the rods 45 and 48, jon the one hand, and the rods 46 and 49, on the storefJtor simulate `the distribution Vof different classesof goods tothe consuming public. '=-f'I--he -pumpl5 is'ofthe centrifugal type as that type delivers water ataconstant pressure rather than at a constant volume. -With a pump having these characteristics, the volume of water deliv- `lered thereby is roughly-proportional to the openopened.

When the volume of liquid in the receptacle 21 representing Inventory increases due to the rate` of iiow from the Supply shelf exceeding the rate of flow from the receptacle 21 to the Demand` distributor, the float 28 sinks in the Stable money .tank l2. When this happens marketwise, the price of the goods drops. Hence, means are provided for indicating the depth of submergence of the tank in terms of price. Such means include a pointer 40 attached to the iioat and a ,Price scale 4| graduated so that the price is a maximum when the receptacle 21 is empty and a minimum when it is full.

As the receptacle 21 is on top of the float 28, the combination is top-heavy. Means are, therefore,

frequired for maintaining the float in upright po- :sition without interfering with its vertical rise and fall with changes in the amount of liquid in *the receptacle 21.

iy According to the present invention, this is accomplished by a parallel linkage support extending throughA a slot 43 in the wall Il, shown more o particularly in Fig. 4. A bar 44 is provided having two cross-rods 45 and 46 passing therethrough and rigidly connected thereto. Abovethe bar 44 is a link 41 likewise provided with cross-rods 48 and 49 rigidly connected thereto. The ends of rods 45 and 48 are'journalled in bearingsl (not shown) mounted on the rear side of the wall Il. The ends of rods 46 and 49 are similarly journalledk in bearings (not shown) mounted on the back wall of the float 28. As rods 45 and`48 are spaced apart the same distance as 46 and 49, and are located in parallel vertical planes, the iioat is maintained in upright position at all times irrespective of the extent to which it is submerged in the liquid in the tank l2. Lateral wobble is eliminated by the fact that the bearings for the ends of the rods 45, 46, 48 and 49 are spaced apart a considerable distance.

l"Ihe"b:f .ck wall of the fioat is spaced well forward'of therear edges of the top and sides of the In the first place, it

other, to be made greater than would otherwise be the case. This flattens out the curved path of movement of the iioat. In the second place, it reduces the effective cross-section of the float and hence increases the variation in the depth of submergence of the float for any given change in the amount of fluid in the receptacle 21. In other words, it makes the apparatus more responsive to variations in the ratio between supply and demand. On the other hand, reduction in the eiective cross-section of the float reduces its weight-supporting power. To overcome that objection, a counterweight 39 is provided to produce a lifting force nearly equal to the weight of the float and receptacle when the latter is empty.

Movement of the rod 44 controls the opening and closing of the valves I8 and 29. Before this 'control mechanism' is described, the valve operating means and the electrical circuits by which such means are controlled will be described.

The stem of valve 29 has on its rear end a worm wheel 56 driven by a worm 5l on a shaft 52 carrying another wormwheel 53 ini mesh with a. worm 54 on the shafti of a motor 56. Similar operating mechanism (not shown) is provided for valve I8- zThe control circuits for the two motors are identical so Aonlyoneais shown diagrammatically in Fig. 3. rThe armature winding is indicated at E58.k To permit .reversal there.are two eldwindings 6| and 62. For convenience in description, it

Vwill be assumedthat it is the Demand valve which is being operated and that the. winding 6I is the one required :for opening the valve. kThere arethree switchesfin serieswith this winding. Switch 63 is the limiting switch which is normally closed and is opened only when the valve nears its fully open position. SwitchA 64 is closed automatically whenthe float sinks (inventories rising and :prices dropping) to. -cause :the Demand valve to open. Switch 65 is rnormally open but is arranged so that it may be closed manually by a push button whenever itis desired to increase Demand arbitrarily. n

` Switches 10,- 1| and 12vhave exactly analogous functions with respect toethe iield winding 62 which, onenergization, causes` the valve to close. In series with the armature there is yet another switch 65 which is normally Vclosed but arranged so that it may be opened manually whenever .it is desired to hold Demand constant arbitrarily. The push button panel is shownin Fig. 5. The buttons 65, 66 and 12 are the operating members of the switches of the same numbers on Fig. 3.

The motor, control circuits and push button switches for operating valve I8 are the same as those described in connection with valve 29, so that no illustration or description thereof is necessary. A

The switches and circuits above described take care of operation of the valves. The apparatus also includes a series of signal lamps arranged alongside of a number of descriptive legends explaining what is happening,- economically speak ing. As shown in Fig. 1, there are ve of such lamps 15, 16, 11, 18 and 19.- For operating these lamps four switches 86, 8 I, 82 and 83 are provided. Two of these switches 80 and 83 are electrically connected so that they operate as single-throw switches, while the other two are double-throw connected. Conveniently, these switches are of the snap-action type described in Eaton U. S. Patent 2,172,613. These switches have a contact arm which snaps back and forth between two contact points as pressure is-applied to or taken off a pin attached to such arm and projecting beyond the body of the switch.

The circuit diagram is shown in Fig. 9. It will be noted that lamp 11 is in series with both switches 8l and 82 so that if either switch is thrown to light its corresponding lamp 16 or 18, the circuit through lamp 11 is broken.

Lamps 16 and 18,- as their corresponding legends indicate, represent movements in prices. Lamp 11 represents stable conditions with supply and demand substantially in balance. Lamps 15 and 19 indicate excessively high and abnormally low prices.

There is another switch 85 in series with lamp 11 which is closed only when the price is within the range to 84. This additional switch is used to prevent the lamp 11 lighting when conditions are more or less stationary but at the same time unduly high or low.

One of the functions of the present apparatus is to give visual signals indicating not only movement of prices but also the direction in which such movement is taking place. Another function is to give a visual signal indicating lack of movement or stable prices.

The mechanism devised for this purpose consiste essentially of a pivotally mounted part normally centered by a spring or springs between two contact points on an arm pivoted to swing about the same axis as said part and connected to the moving member whose movement is to be indicated. A dash-pot is connected to said part to slow down the movement of the latter so that on all movements of the arm, except the very slowest, the dash-pot will oier greater resistance to such movement than the centering springs so that said part will lag behind the arm and consequently contact one or other of the contacts. Which contact is engaged depends upon the direction in which the arm moves. As soon as the arm comes to rest, the springs slowly move the dash-pot until such part is once' more centered between the two contacts.

In the particular construction illustrated, a disc 90 is fixedly mounted on a rotatable shaft SI to which is rigidly connected a rocker arm I I0. See Fig. 7. One end of this arm is connected to the piston rod III of a dash-pot H2. The other end of the arm I I carries a counterweight I I3 to oliset the weight of the piston and piston rod of the dash-pot.

Loosely mounted on the shaft 9I is another rocker arm 92, pivotally connected at 93 to the link 94 which, in turn, is connected at 95 to the arm 44. Consequently, vertical movements of the oat produce corresponding angular movements of the rocker arm 92.

On the outer end of rocker arm 92 are mounted the snap switches 8| and 82, previously referred to, with their operating pins in contact with or closely adjacent to the top and bottom, respectively, of the rocker arm IIO. When such end of the arm S2 moves upwardly, the switch 8| is closed and the adjacent end of the rocker arm I I0 is moved upwardly. A downward movement of such end closes the switch 82. Springs II5 and II6 are provided for the purpose of returning the rocker arm IIII into parallelism with the arm 92 against the resistance oiered by the dashpot II2. In this position the switches 8| and 82 are positioned as shown in Fig. 9.

Arranged around the periphery of the disc 90 are seven cams |00, |0I, I02, |03, |04, |05 and |06 for operating switches 85, 1I, 64, 83, 80, 88 and 89, respectively. Conveniently the cams are mounted so that thelr position may be adjusted circumferentially with respect to the disc to produce operation of the switches at any desired angular position of the disc.

Subject matter disclosed but not claimed in this application is claimed in divisional application Serial No. 53,561 led by applicant on Oct. 8, 1948.

I claim:

l. A device for illustrating economic laws, comprising a tank containing liquid, a float therein, a liquid receptacle carried by said oat, means for admitting liquid to and discharging liquid from such receptacle simultaneously to represent commodity supply and demand, a price scale at one side of the float and receptacle, a pointer carried by the latter for indicating on the scale vertical movements of the iloat and receptacle. a valve for controlling the rate of such admission and a reversible electric motor for opening and closing said valve, a switch therefor adapted to be closed by the oat to run the motor in one direction when the float rises above a predetermined height and a second switch therefor adapted to be closed by the float to run the motor in the opposite direction when the oat falls below a predetermined height.

2. A device for illustrating economic laws, comprising a tank containing liquid, a oat therein, a liquid receptacle carried by said float, means for admitting liquid to and discharging liquid from such receptacle simultaneously to represent commodity sup-ply and demand, a price scale at one side of the float and receptacle, a pointer carried by the latter for indicating on the scale vertical movements of the float and receptacle, a valve for controlling the rate of such discharge and a reversible electric motor for opening and closing said valve, a switch therefor adapted to be closed by the float to run the motor in one direction when the float rises above a predetermined height and a second switch therefor adapted to be closed by the float to run the motor in the opposite direction when the Iloat falls below a predetermined height.

JAMES D. MOONEY.

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

UNITED STATES PATENTS Number Name Date 1,747,357 Frevier Feb. 18, 1930 2,219,472 Defandorf Oct. 29, 1940 2,281,368 Mooney Apr. 28, 1942 2,351,580 Beckman June 20, 1944 2,416,267 Landon Feb. 18, 1947

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