US2592905A - Apparatus for setting thermostatic controls - Google Patents

Description

April 15, 1952 3, J, JACOBS 2,592,905

APPARATUS FOR SETTING THERMOSTATIC CONTROLS Filed April 26, 1951 2 WSSHEET 2 v 21 F Q) QPERATION LEVER Z0 A24 ,25 3 MICRO Z '1: J

SWITCH INVENTOR sfirnandbe 710063 wwm ATTORNEY Patented Apr. 15, 1952 UNITED STATES PATENT OFFICE APPARATUS FOR SETTING THERMOSTATIC CONTROLS The present invention relates to the setting and adjustment of heat-control mechanism and it relates more particularly to the adjustment and setting: of intermittently-operating heating or cooling systems.

An object of the present invention is to provide novel apparatus for setting and adjusting heatcontrol mechanism.

Another object of the present invention is to provide a novel tool for the rapid and accurate setting and adjusting of heat-control apparatus of the intermittently-operating type. Still another object of the present invention is to provide a new and improved tool for setting and adjusting mechanism intended to control the thermal requirements of a building by the conjoint use of chronometricv means and thermostatic means controlled by temperature outside the space with respect to which heat transfer (either heating or cooling) is to be made.-

Other objects and advantages of the present invention are apparent in the following detailed description, appended claims and accompanying drawings.

One type of temperature-control system which has been found highly efiicient in the maintenance of relatively uniform temperature, with maximum efiiciency in the utilization of fuel,- is that which employs a heat-sensitive element located on the outside of the building, in conjunction with mechanism which places the heating system in operation at predetermined intervals (for example, once an hour) for a variable length of time; the length of heating time varying with the outside temperature. A system of this type is sold by Automatic Devices 00., Chicago, Illinois, under the trade-mark Weather- Man.

This system employs a cam-disc driven by a synchronous motor through one revolution per day, having a series of cam-teeth or sections formed on its periphery, each tooth or section corresponding to a predetermined period of time (for example, one hour) and a cam-follower carried by a pivoted lever constructed and arranged alternately to be raised by the higher portion of each successive cam-tooth and thereafter to ride over the tip of the tooth and to fall to a point adjacent the lower portion of the next successive tooth; the up-and-down movement ofthe lever serving to operate a micro-switch which turns the furnace controls on and ofi. The micro-switch is itself pivotally mounted and is provided with cam mechanism actuated by the outside thermostatic element, so as to be moved toward or away from the lever with variations 3 Claims;

in outside temperature. in this way, the points at which the micro-switch is opened and closed by the lever vary with the outside temperature, so. that, with a relatively higher temperature, the micro-switch is closed and the heating system is operating for only a relatively small fraction of each hour, while, with a relatively lower temperature, the micro-switch is closed and the heating system is operating for a relatively longer fraction of the time.

However, one serious disadvantage of this type of heat-control system has been the fact that a great deal of time is required to set and adjust the mechanism to give the correct heating time, depending upon the characteristics of the particular building and heating system involved.

The extremely time-consuming. trial-anderror procedure which has heretofore been necessary in setting and adjusting this type of heatcontrol system is as follows: The mechanic permits the mechanism to run for an hour or two and times the number of minutes per hour during which the heating system is in operation. If he finds, for example, that the heating system is in operation for 25 minutes out of every hour, whereas it should be operating for only 20 minutes per hour at that particular temperature, he turns an adjusting screw to lower the heating time. He must then wait for at least another hour to time the heating period with the new adjustment setting. He may then find that he has over-compensated and is now getting only 17 minutes per hour and must then make a new adjustment and must repeat the timing operation, requiring at least another hour, to determine whether he has now corrected the heating time to that actually required at the given temperature.

It can readily be seen that a half-day to a day can be taken up simply in adjusting or setting the already-installed heat-control system. If, as is not uncommon, the system goes out of adjustment, at some later date, a similar amount of time is used up in placing the system back in adjustment.

This long drawn out procedure has greatly increased the cost of installing and servicing heatcontrol systems .of this type.

According to the present invention there has been developed, for the first time, a novel tool for setting and adjusting this intermittentlyoperating type of heat-controlsystem, by means of which the heating time per hour, at a given temperature, can be determined in a matter of seconds and the adjustment or setting of the system can be completed within a few minutes, with a far greater degree of accuracy than has heretofore been possible.

Generally speaking, the present invention contemplates a novel adjusting tool which is generally disc-shaped with a camming surface extending through substantially more than 180 degrees of are, one end of the camming surface having a radius corresponding to that of the bottom of one of the teeth of the cam-disc, and the other end of the camming surface having a radius corresponding to that of the top of the aforesaid tooth, whereby the camming surface represents a greatly circumferentially expanded contour of one of the cam-teeth; the tool being constructed and arranged to be mounted upon the shaft, in place of the cam-disc, and to be freely rotated, by hand, upon the shaft until the cam-follower is raised sufficiently to open the micro-switch, this point being read olf against appropriate calibrations upon the tool, to give a direct indication of the heating time which would have re sulted had the mechanism been operating, in the normal way, with the cam-disc in place. If this reading indicates excessive or insufiicient heating time, an appropriate adjustment is made in the mechanism and the procedure is repeated, the tool being again rotated by hand to give a direct reading of the heating time which would have resulted with the new setting of the mechanism.

Since it requires only a few seconds for each manual rotation of the tool, the entire adjusting or setting operation can be completed in a matter of minutes. The results obtained when checked against actual heating time, by means of a stop watch, have proven to be extremely accurate; the variations being so small as to be negligible.

For the purpose of illustrating the invention, there is shown in the accompanying drawings one form thereof which is presently preferred and which has been found in practice to give satisfactory results. It is to be understood, however, that the present invention is not limited to the precise instrumentalities and arrangements illustrated and that the several structural elements can be variously arranged and organized, without departing from the spirit or essential attributes of the invention.

Referring to the accompanying drawings in which like reference characters indicate like parts throughout:

Figure 1 is an elevational view of a heat-control unit employing a toothed cam-disc of the type referred to above.

Figure 2 is a view generally like that of Fig. 1 but showing the toothed cam-disc removed and replaced by the novel tool of the present invention.

Figure 3 is a schematic elevational view showing the relationship of the several operating parts of the embodiment of Figs. 1 and 2 when the tool is in the starting position shown in Fig. 2.

Figure 4 is a cross-sectional view generally along the line 4-4 of Fig. 3.

Figure 5 is a view generally like that of Fig. 3 but showing the appearance of the parts after the tool has been rotated to a point at which the cam-follower and lever have been raised to open the micro-switch.

Figure 6 is a cross-sectional View taken generally along the line 6-6 of Fig. 5.

In Fig. 1, there is shown a heat-control unit of the type sold by Automatic Devices Co. of Chicago, Illinois. under the trademark Weather- Man, the principle of operation of which is disclosed in Kucera Patent 2,333,319, to which reference is made for a more complete showing and description, than are incorporated herein.

The unit of Fig. 1 includes a housing or case l0 provided with a hinged side or lid H, and adapted to be fastened on the outside of the building whose temperature is to be regulated.

Within the case H) is mounted a synchronous motor (2 connected, by suitable gearing (not shown), to a shaft I3 which is rotated by the motor at a rate of one revolution per day. The shaft i3 is provided with an axially-extending fiat surface M.

A compound cam 15 is removably mounted upon the shaft l3 in keyed relationship thereto: the cam having a central opening (not shown) corresponding to the cross-sectional configuration of the shaft. The cam I5 is held in place by a screw-threaded thumb-nut l6 and tension spring-washer I! which bears against the outer face of the cam and maintains it in vertical alignment with a cam-follower to be described hereinbelow.

The compound cam l5 includes, as one of its elements a cycle-disc I8 having a plurality (for example, sixteen) of cam-teeth l9, each tooth representing 2 of the circumference of the disc so that it requires one hour for a single tooth to pass a predetermined point, at the fixed irate of rotation of the shaft and the disc.

A cam-follower 2B is carried by one end of a generally horizontal lever 2!, the other end of which is pivotally mounted as at 22, whereby the cam-follower 20 is located above and in vertical alignment with the cam-disc l8 and normally bears against one of the cam-teeth I9.

A micro-switch 23 which is of generally conventional construction having a protruding pin 24 normally spring-urged to outermost position wherein the switch is open, is mounted upon a generally horizontal arm 25, one end of which is pivotally mounted as at 26 and the other end of which is provided witha follower-finger which bears against a conoidal cam 28 mounted upon a shaft 29 which is rotatable and also axially'movable.

The pin 24 is located below the lever 2| sothat downward movement of the lever will force the pin inward to close the micro-switch 23.

One end of theshaft 29 is connected to a diaphragm-bellows 30 located within a bulb 3| disposed on the outside of a case 10 and containing xylol or some other suitable material the amount of volatilization of which varies with the temperature and causes corresponding movement of the diaphragm-bellows 30.

As can be seen particularly in Fig. 3, inward movement of the diaphragm-bellows 30 (resulting from a rise in temperature) from the solid line position to the dash-dot line position causes inward movement of the shaft 29 and the conoidal-cam 28 and results in a counter-clockwise tilting of the arm 25 so as to move the pin 24 further away from the lever 2i.

The other end of the shaft 29 is provided with an adjusting knob 32 which permits manual axial rotation of the shaft 29 so as to bring into cooperative relationship with the follower-finger 21 a different meridional contour of the conoidalcam 28. This permits adjustment of the mechanism to accommodate differences in thermal requirements of the particular heating system or locality.

The cam-disc l8, the cam-follower 20, the lever 2|, and the micro-switch 23 are so positioned that, when the bottom 33 of one of the teeth I3 is below the cam-follower 20, the lever 2| will rotate clockwise until it strikes and depresses the pin 24 of the micro-switch 23, thereby opening the micro-switch and putting the heating system (not shown) into operation. this position, the cam-follower 28 is out of contact with the tooth I9. As the cam-disc |8 rotates slowly (clockwise in Fig. 3) successively higher portions of the cam-tooth are brought into alignment with the cam-follower until finally the tooth contacts and raises the cam-follower sufiiciently to permit. the pin 24 to return to its original: outermost position opening the micro-switch 23 and shutting off the heating system.

For the remainder of the hour the cam-follower and the lever will continue to be raised gradually by the cam-tooth l8 until, at the end of the hour, the cam-follower 28- willride over the tip 34 of the tooth l9 and will. then fall to its. lowermost position, re-closing the micro-switch 23 and re-starting the heating system.

It is apparent that, at a given outside temperature, the micro-switch will be closed and the heating system will be operating for a predetermined fractionof the time.

With a rise in outside temperature. resulting in an inward movement of the conoidal-cam 28, the pin 26 of the micro-switch 23 will be in a somewhat lower position, which will mean that it will be released sooner upon upward movement of the cam-follower 28 and the lever 2|. as a result, the micro-switch will be closed and the heating system will be in operation for only a smaller fraction of each hour.

Conversely, a drop in outside. temperature will result in outward movement of the conoidal-cam 28 and a raising of the pin 24 sothat the microswitch 23 will remain closed and the heating system will remain in operation for a greater portion of each hour.

The cam-follower 28 is provided with a pointer which overlies the outer face of the cam-disc l8 and extends in proximity to appropriate hourly calibrations on the disc.

In addition to the adjusting knob 32 (which is primarily a cold weather adjustment to vary the degree of heat delivered at low temperatures), adjusting screws 38 and 31 are provided to vary the heat delivered in mild weather and to vary the temperature at which heat is cut off in mild weather.

As mentioned above, these various adjustments require manipulation when the heating system is first installed and, prior to the present invention, each such adjustment required a long wait on the part of the service-man before he could determine whether additional adjustments were necessary.

According to the present invention, when it is desired to set or adjust the mechanism, the cam I5 is removed from the shaft l3 by first unscrewing the thumb-nut l8, and is replaced by the novel tool 38.

The tool 38 is a relatively thin, more or less disc-like member, formed of sheet-metal or synthetic resin or other suitable material and is provided with a central reinforcing hub 39 having a circular opening 48 fitting over the shaft l3, in freely rotatable relationship therewith, after the spring-washer I1 and thumb-nut l6 are replaced.

The tool 38 is provided with an outer peripheral camming-surface 4| which extends through 300 degrees or are. One end 42 of the cammingsurface 4| has a radius corresponding to the radius of the tooth bottom 33, while the other end 43 of the camming-surface 4| has a radius corresponding to that of the tooth top 34. The radius of the camming-surface 4| increases more or less uniformly from the smaller end 42 to the larger end 43 so that the camming-surface 4| represents a greatly circumferentially expanded contour of one of the individual cam-teeth !9 described above. Appropriate calibrations are provided upon the outer face of the tool 38. These calibrations, as shown in Figs. 3 and 5, may include the numbers 0-6-10 and so on up to 60, with subdivisions for units and half-units. However, any other suitable calibrations could be employed instead.

In setting or adjusting the heat-control mechanism, the tool 38 is first placed in the position shown in Figs. 3 and 4 wherein the smaller end 42 of the camming-surface 4| is in line with the cam-follower 20. In this position, the lever 2| will be in contact with the pin 24 of the microswitch 23 so that the micro-switch will be closed and the heating system will be operating.

The tool 38 is then rotated slowly by hand, relative to the shaft |3, until the cammingsurface 4|. contacts the cam-follower 2| and raises the lever 2| sufficiently to release the pin 24 and to open the micro-switch 23 as shown in Figs. 5 and 6. The point at which this occurs is read off against the calibrations on the tool, by means of the pointer 35.

For example, if the micro-switch is opened at a reading of 30, as shown in Fig. 5, this indicates that, with that particular setting of the various adjusting screws, the heating system would have been in operation for 30 minutes out of each hour. If this figure is too high or too low (as can be determined by reference to an appropriate chart supplied by the manufacturer of the heat-control system, showing the relationship of temperatures to heating times) one or more of the adjusting screws or knobs can be appropriately manipulated.

The testing procedure can then be repeated. That is, the tool 38 can be reset to the starting position shown in Fig. 3 and manually rotated to the point at which the micro-switch re-opens. The new reading of the tool calibrations relative to the pointer 35 can then be checked against the manufacturer's chart to determine whether the heating time is now correct.

If this shows an over-correction or an undercorrection, the adjusting screws can be further manipulated and'the operation once again repeated, until the heating time indicated by the tool 38 corresponds exactly to the heating time called for by the manufacturers chart.

Tests have proven that when the cam I5 is replaced, the actual heating time corresponds precisely to the figure indicated by the tool 38.

Inasmuch as it requires only a few seconds for each manual rotation of the tool 38, the entire setting or adjusting operation is but a matter of minutes, assuming, of course, that the heat control mechanism itself is not defective.

It is apparent, therefore, that it is possible to effect enormous savings in the time of servicemen and others who would normally be required to install and periodically check this intermittent-heating type of heat-control system.

While the 300 degree cam-surface has been found to be highly effective and accurate, the present invention is not limited to that figure and, instead, the camming-surface can be extended through greater or lesser circumferential dimensions. It is preferred, however, to employ substantially more than 180 degrees of are for the camming-surface t: l, in order to obtain maximum accuracy. The calibrations can be applied to the tool 38 in any suitable manner, as for example, by printing, engraving, etching, etc.

Where the tool is formed of synthetic resin, it is possible to mold it as an integral one-piece element, and to form raised or recessed calibrations during the molding operation, by providing suitable markings on the mold. v

The present invention may be embodied in various other forms and, accordingly,.the foregoing embodiment is to be considered as illustrative and not restrictive, reference being made to the appended claims as indicating the scope ofthe invention.

I claim: v 1. For use in setting heat-control apparatus having a shaft rotated at constant speed and having a rotary cam detachably mounted upon said shaft and adapted to be rotated thereby once every day and provided with a plurality of relatively small teeth on its periphery, and having a follower lever cooperating with said teeth and adapted to be reciprocated thereby, and having a micro-switch constructed and arranged to be periodically actuated by the reciprocating lever so as periodically to start up and shut off the heating system, and having temperature-controlled means for varying the point of actuation of the micro-switch by the lever thereby to vary the ratio of heating time to non-heating time, and having one or more manual adjusting means for correcting the aforesaid ratio of heating time to non-heating time; a generally disc-like tool having a peripheral camming surface extending through a substantial portion of the circumference of the tool, the radius of the tool at one end .of the camming surface corresponding to the radius ofthe rotary cam at the low point of its teeth and the radius of the tool at the other end of the camming surface corresponding to the radius of the rotary cam at the high point of its teeth, the contour of the camming surface corresponding generally to the contour of one of the rotary cam teeth but being greatly circumferentially expanded relative thereto, said tool having circumferentially-distributed calibrations formedthereon, said tool being constructed and arranged manually to be rotated upon the shaft just sufficiently to cause its camming surface to raise the follower lever enough to actuate the micro-switch and shut off the heating system,

the calibration reading of the tool at the point REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,694,164 Crosthwait Dec. 4, 1928 2,095,355 Cate Oct. 12, 1937 2,333,319 Kucera Nov; 2, 1943

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