US2540828A - Clock balance escapement device - Google Patents

Description

Feb. 6, P, J MCCULLOUGH CLOCK BALANCE ESCAPEMENT DEVICE Filed Nov. 15, 1947 2 Sheets-Sheet l v INVENTORI PAUL J. MCCULLOUGH AT TORNEY.

Feb. 6, 1951 P. J. M CULLOUGH CLOCK BALANCE ESCAPEMENT DEVICE 2 Sheets-Sheet 2 Filed Nov. 15, 1947 FIG. 9.

INVENTORi PAUL J. MCCU LLOUGH ATTORNEY,

Patented Feb. 6, 1.951

UNITED PATENT OFFICE 'JGLOCKZ BALANCE ESCAPEMENT :DEVICE .Paul..J.' 1Mc"Cullough, St. Louis, M0,, assignor,;by

mesne assignments, ,to'iThe' Toastswell Commanmllneorporatd, St. "LouisfiMo; a corpora- -tion--of Missouri v-ApplicationNovember 15, .1947, Serial No..'7-86,1'89

Claims. r1 Theinvention relates to clock, mechanismland more particularlyto clock mechanism; for wuselin timing electric toasters .and other .devices.

Reference -is made .to PatentiNoQ862,836,-is-

sued to the present. applicantNovember 1(1, 194.4,

noiseless, if special attentionis .directedto it, a

slight clicking sound can be, heard.

The main object of the present .invention'is to eifect even more quiet operationthan heretofore of clock mechanisms constructed -of parts .made and assembled in quantities andof inexpensive-materials, such asmetal stampings, and to keep the parts in adjustmentirrespective of Wear.

This is accomplished "by .causing the spring member to thrust the balance wheel 'shaft'substantially in the direction of thrust exertedby the scape'wheel on the balance wheel. andpreferably towards the vapex of .an angular aperture. Thisarrangement' restrains movement of thelbalance wheel in "directions both parallel antiperpendicular to the direction of thrust.

In Patent No. "2,362,835, the'balance iwheel comprises a pair of discs clamping between them the base of the Ll-shapedpallet and one of .which palletlegs. The balance wheeliiisc preferably is madeof sheet metal approximately .050"1thick and thepallet preferablyis made of. spring wire approximately .0l4" in'diameter. "It is impractical to punch a circular holein sheet metal smaller in diameter than the .thiekness of the metal, so that'the diameter eftheholespunched in the balance wheel disc for the palletdegsis relatively larger .than the diameter of thepallet legs. The metal of the discsurrounding'thepallet legs cannot readily be pressed firmly into .surrounding engagement with the pallet legs. En-

is provided with circular openings to receivethe legs. .to closely approach the diameter of 'the,.pa1let legs andto permit the metal at'the side of the .slotsto be pressed firmly into engagement .with the pallet legs and securelyhold them in position held in spaced .relation'by posts )3. gears, .4, 5 and fi aremounted upon individual gagement and disengagement of the pallet with :the scape wheel causes constant flexing of the pallet material where theilegsjointhe connecting part which has been strained initially in makingthe sharp bend and thismay result'inithe "legsfracturing at the bend. Also, when press- .ingthemetal about the disc apertur into engagement with the pallet "legs, the latter are 'likelyto shift inthe aperture resultingin'inaccuraciesin the finished balance wheel.

.Another object is to overcome these structural .difficultiesby providingelongated narrow slots in ,the balance Wheel disc to receive thepallet Theaslots can be made sufiiciently-narrow and also ,to reinforce them at the. bent portions. With this arrangement, only a single disc is needed and the pallet legs maybemade sepa- ..rately.and of straight pieces of thin wire and Withoutlthe connecting part therebetween.

"The above and other-detail objectsas willsappear below are attained b the structureillustrated in the accompanying.drawings. in which:

.Figure l is a side view of a clock mechanism embodying the invention, one side plate being .removed.

"Figure 2 is a detail vertical sectiontaksnapproximat'elycn the line 22 ofFigure'l.

L'Figures 3 and 4 are detail vertical sections, drawnto enlarged scale, taken on line :33.of Fjgure'2 and showing the scapewheel and the balance wheel and associated partsin different positions.

JFiigure'S'isa detail of a portion of the spring "member, the balance wheelv shaft in vertical sec- .tion andits bearing, drawn to enlarged scale.

Figure 6 is a perspective view of a balance wheel constructed accordingto the invention.

"Figure "!.is a side view thereof.

Figure 8 is a detail side viewof a balance Wheel disc before the pallets and .shaftare assembled thereto, and

.Figure 9 View similar to Figurel3 show ing another form of the invention.

The clock frame comprises .sideplates land! A vtrainpf shaftsjournaled in plates [and]: and associated with pinions 1,5;and L9,..respectively. Arshaft 5.0

.mounting pinion ii and journaled in circular .apertures mainplates I I and.2 also. carries :a scape In the embodiment shown in Figures 1 to 8, associated with scape wheel I I is a balance wheel I2 mounted on a shaft I3 journaled in square apertures I 3a in plates I and 2. The apex of one of the angles between adjacent sides of each aperture I3a preferably is positioned at the end of aperture I3a remote from apertures Ida.

Balance wheel I2 comprises a single plate disc I4 having elongated slots Md and provided with a pallet structure preferably formed by a U- shaped unit of small diameter spring wire with its cross piece I8 applied to one face of the disc and with its legs I6 and II extending outwardly from the opposite face of the disc. After the pallet structure is applied to the disc, the metal of the latter is deformed or offset to tightly press the metal against opposite sides of the legs at points spaced from the apex of the sharp angle formed by the bends which connect elements I8 with elements I6 and II. With this arrangement fiexure of the pallet structure restricted to the portions of elements I6 and II projecting from the disc and is not applied to the right angle bend in the wire where repeated flexing might readily result in failure or the wire.

Balance wheel I2 oscillates on its shaft to alternately engage and disengage pallet legs i and II with the scape wheel teeth and the spring quality of the pallet structure gives the balance wheel its oscillatory movement and functions as does the hair spring in the usual clock mechanism. Furthermore, the yielding action of the pallet structure avoids the pronounced click usually present in inexpensive simple clock mechanisms and produces a quiet clock operation which is highly advantageous in timing devices for appliances such as toasters, etc.

To further contribute to the quiet efficient operation of this device and to avoid the necessity of fine fitting of the balance wheel shaft pintles IS in their bearings, a spring member 26 having a bow-like contour with hooked ends extends around a post 3 and has one of its ends engaging a pintle I9 of shaft Ill and the other end engaging an inward projection 2I on plate I. Spring member 20 engages the adjacent surface of the associated pintle I9 and thrusts the opposite surfaces of both pintles I9 toward the apices of the bearing surface angles of apertures I 3a in a direction substantially in alignment with the general direction of thrust exerted by scape wheel II on balance wheel I2 as the teeth of scape wheel II alternately engage pallet legs IB and IT. This arrangement provides for rolling contact of pintle I9 of shaft I3 and the associated looped end of spring member 2!! as do scribed in Patent No. 2,362,836 mentioned above.

The force exerted on balance wheel I2 during its engagement by the scape wheel is in a direction substantially perpendicular to the pallet engaging face of the tooth engaging the pallet leg. When a tooth of scape wheel II engages pallet leg I6, as shown in Figure 3, the direction of thrust of scape wheel II on balance wheel I2 is indicated by arrow at. When a tooth of scape wheel II engages pallet leg II, as shown in Figure 4, the direction of thrust of scape wheel II on balance wheel I2 is indicated by arrow 1/. Between each such engagement, no force is exerted by scape wheel iI on balance wheel I2 and shaft pintles I9 may tend to move away from the opposing bearing surfaces of apertures I3a, particularly when the pintle supporting bearing surfaces incline downwardly away from the apices. Spring member 2!! maintains shaft pintles IQ of balance wheel I2 in apertures I311. substantially in the positions which they normally assume when balance wheel I2 engages scape Wheel II, thus quieting the mechanism. If the sides of apertures I3a should become worn, the thrust of spring member 20 on balance wheel pintle I2 holds the balance wheel pintle against the bearing surface substantially opposite to the scape wheel and thrusts the balance wheel in the direction of thrust of the scape wheel on the balance wheel.

The structure shown in Figure 9 is similar to that previously described in Figures 1 to 8 except that spring member 30 has its looped ends engaging pintle 3| of scape wheel shaft 32 and pintle 33 of balance Wheel shaft 34. Apertures 32a and 34a both may be circular and receive pintles 3| and 33, respectively, but need not fit them closely. Spring member 30 engages adjacent surfaces of pintles SI and 33 and thrusts the shafts apart with the opposite surfaces of the pintles against the bearing surfaces of apertures 32a and 34a in a direction substantially in alignment with the general direction of thrust exerted by scape wheel 35 on balance wheel 36 as the teeth of the scape wheel engage balance wheel pallet legs 3'! and 38.

The above described structures attain the objects set forth in the introductory portion of this specification and provide rugged, inexpensive mechanisms which are so quiet as to be almost inaudible and which have long useful lives, notwithstanding rough handling and other disadvantageous conditions under which clocks must work when used in the type of equipment mentioned.

The details of the structure may be varied substantially from the specific disclosure herein without departing from the spirit of the inven tion and the exclusive use of those modifications coming within the spirit of the claims is contemplated.

What is claimed is:

1. In a clock escapement device, a balance wheel, a scape wheel associated therewith, a shaft mounting said balance wheel, and an element yieldingly thrusting said shaft in a direction substantially in alignment with the general direction of thrust exerted by said scape wheel on said balance wheel.

2. In a clock escapement device, a balance wheel, a scape wheel, shafts mounting said balance wheel and said scape wheel and each hav ing a journal, a plate having apertures receiving said journals and forming bearings therefor, said balance wheel and said scape wheel exerting thrusts one on the other in substantially opposite directions, and a spring element thrusting said balance wheel shaft in a direction substantially in alignment with the general direction of thrust exerted by said scape wheel on said balance wheel.

3. In a clock escapement device, a balance wheel, a scape wheel associated therewith, shafts mounting said balance wheel and said scape wheel and each having a journal, said balance wheel having a pair of widely spaced pallets, said scape wheel alternately engaging said pallets and thrusting said pallets in different directions, and a spring thrusting said balance wheel shaft in a direction between the directions of said thrusts.

4. In a clock escapement device, a balance wheel, a scape wheel, shafts mounting said balance wheel and said scape wheel and each having a journal, a plate having apertures receiving said journals and forming bearings therefor, and a spring element having one end anchored to said plate and having the other end yieldingly thrusting said balance wheel journal against the side of the associated aperture most remote from said scape wheel.

5. In a clock escapement device, a balance wheel, ashaft mounting said balance wheel and having a journal, a plate having an aperture receiving said journal and forming a bearing therefor, said aperture having at least two sides forming the apex of an angle, and a spring element yieldingly thrusting said journal towards the apex of said angle.

6. In a clock escapement device, a balance wheel, a scape wheel associated therewith, shafts mounting said balance wheel and said scape wheel, and a spring element thrusting said shafts in opposite directions.

'7. In a clock escapement device, a balance wheel, a scape wheel, shafts mounting said. balance wheel and said scape wheel and each having a journal, a plate having apertures loosely receiving said journals and forming bearings therefor, and a spring element yieldingly thrusting said journals apart and against a side of the associated aperture.

8. In a clock escapement device, a balance wheel, a scape wheel, shafts mounting said balance wheel and said scape wheel and each having a journal, a plate having apertures loosely receiving said journals and forming bearings therefor, said balance wheel and said scape wheel exerting thrusts one on the other in substantially opposite directions, and a spring element thrusting said shafts in directions substantially in alignment with the general directions of thrust exerted by said scape wheel and said balance wheel on one another.

9. In a clock escapement device, a balance wheel, a scape wheel, shafts mounting said balance wheel and said scape wheel and each having a journal, a plate having apertures receiving said journals and forming bearings therefor, and an element engaging adjacent surfaces of said journals and yieldingly thrusting said journals apart and thrusting the opposite surfaces of said journals against boundaries of the apertures.

10. Structure as described in claim 9 in which the journal engaging element comprises a spring having a hook at each end.

11. In a clock escapement device, a balance wheel, a scape wheel associated therewith, shafts mounting said balance wheel and said scape wheel and each having a pintle, a plate having apertures receiving said pintles, a spring element in engagement with said pintles and yieldingly thrusting said pintles apart against boundaries of the associated apertures.

12. In a clock escapement device, a balance wheel, a scape wheel associated therewith, shafts mounting said balance wheel and said scape wheel and each having a journal, a plate having apertures loosely receiving said journals and forming bearings therefor, said balance wheel having a pair of widely spaced pallets, said scape wheel alternately engaging said pallets and thrusting said pallets in different directions, the reactions from said thrusts urging said scape wheel in directions substantially opposite to the directions of said thrusts, and a spring thrusting said balance wheel shaft in a direction between the directions of said thrusts on said pallets and thrusting said scape wheel shaft in a direction between the directions of said thrusts on said scape wheel.

13. In a clock escapement device, a balance wheel comprising a disc-like member having a pair of slots, pallet structure consisting of a U of spring wire with its cross bar adjacent one surface of said disc and with its legs extending through said slots in said. member and projecting from the other surface, portions of said member adjacent said legs tightly pressing against opposite sides of said legs outwardly of their connection to said cross bar.

14. In a clock escapement device, a balance wheel comprising a disc-like member having an elongated slot, a flexible pallet extending through said slot and held firmly therein by opposing portions of the disc engaging opposite faces of said pallet substantially at the point where the pallet emerges from said disc.

15. In a clock escapement device, a mounting plate having a substantially polygonal aperture, a balance wheel having a shaft provided with a journal loosely received in said aperture, and a spring element exerting a constant thrust on said journal parallel to said plate to hold the journal against play in a bearing formed by the converging sides of an angle of said aperture.

PAUL J. MCCULLOUGH.

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

UNITED STATES PATENTS

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