US3080756A - Thermal responsive actuator - Google Patents

Description

March 12, 1963 w. E. BAKER 3,080,756

THERMAL RESPONSIVE ACTUATOR Filed Dec. 5, 1958 INVENTOR WILLIAM E. BAKER HIS ATTORNEYS n e S s Patent I1 3,080,756 THERMAL RESPONSIV E ACTUATOR William E. Baker, Needham Mass, assignorto Standard- Thomson Corporation, Waltham, Mass., a corporation of Delaware Filed Dec. 5, 1958, Ser. No. 778,520

9 Claims. (Cl. 73-3683) This invention relates to a thermal responsive actuator; This invention isan improvement upon'the thermal responsive actuator of Patent No. 2,806,375, assigned to Another object of this invention is to provide such asealing." 'means' which is capable of effective sealing throughout a'very high number of operations of the actuator rod.

Another object of-this invention is to provide 'a thermal responsive actuator which maybe produced at-compar'a tively low cost.

"Other objects and advantages reside in the construction of parts,'the' combination thereof, the method of manufacture, and the 'mode of operation, as will become more apparent from the following description.

'-In.the drawing,- FIGURE'I is a sectional view of a thermal responsive actuator of this invention, showin the actuator in a deactuated condition.

FIGURE 2 is a sectional view similar to FIGURE l,

showing the actuator. in an actuated position.

FIGURE 3 is a sectional view taken-substantially online 3--3- of FIGURE 1. I v

"FIGURE 4- is a fragmentary sectional view showing a portion of a sealing means fora reciprocally operable actuator rod with the actuator rod removed. Referring-to the drawing in detail, a thermal responsive-actuator of this invention'comprises a container which may be substantially cylindrical-in shape. The

container 10 has a diverging end portion 12 within which acover member 14 is disposed- The cover member 14 is held firmly against the diverging end portion 12 by means-of a bent-over portion 16, as clearly shown in FIGURES 1 and 2.

"Ihe cover member '14 is provided with-an opening therethrough at substantially the center thereof. The edge of the opening on the inner surface of the cover member 14 is arcuate, as shown by reference numeral 20.

face of the'cover member 14 and integral therewith is a hollow ne'clt'22 having an arcuate bent-over end 24. A

body of elastic material or elastomeric material 25 has a main portion 26 within the container 10. The main portion 26 has a-flange 28 which engages the cover mem ber 14 and the diverging portion 12 of the container 10.

22 and the bent-over portion 24 thereof. Preferably the flange ZS-and-the portions 30 and 32 of the elastic body 25 are bonded to the cover member- 14 by any suitable means.

lheelastic body 25 has abore or cavity 34 therein, as

high fluid pressures within the shown in FIGURE 4. The bore or cavity 34 extends through the portions 32 and and into the main portion" 26. Wall members 36 form the portion of the bore'34 which is withi'n'the main portion 26, as shown in FIG URES l, 2, and 3. The cavity 34 extends through most of the length of the main portion 26 of the elastic'body- 25. i

The bore 34 is adapted to snugly receive an actuator rod 40 which is shown as being provided with .a tapered end 42-, as shown in FIGURES l and 2.

Within the container 10 and exterior of the elastic body I 251s a body or quantity of thermal responsive expansible contractible' material '44. The thermal responsive mate rial 44 may preferably be any material such as wax orl the like. This thermal responsive expansive material 44 may be any element or any combination of elements giv- 1 mg the material the physical property characteristics of i a high coetficient of expansion over a given temperature range. A material is selected to provide the desired ex pansion and flow characteristics over the desired temperature range for any given application of the thermal. responsive device.

- As shown in FIGURE 4, the upper end of the portion I 32 of the elastic body 25 has an opening forming the mouth of the bore 34. The diameter of the opening 50" is'slightIy smaller than the'diameter of the actuator rod! 40. The wall surface of the'bore 34,adjacent the open-I; ing 50 is provided with a series of tapered annular'por-i tions- 51. Each tapered portion 51 of the wall surface of the bore 34 terminates in a diameter larger than the opening 50. Also, the wall surface of the bore 34 within the portion 32 of the elastic body 25 has a pluralityof surfaces 52 which are substantially normal to the axis" of the bore 34. Each of the surfaces 52 has an opening' therein substantially equal to the opening 50. Therefore,

when the actuator rod 40 is disposed within the bore 34,

- the portion 32 firmly seals against flow of fluids into the :55 Extending substantially normally fromtheouter suit bore or cavity 34. Thus, fluids are prevented from flowing along the surface of the rod 40 into the cavity or bore34. FIGURE 1 shows-a thermal responsive actuator of this' invention in a deactuated condition. However, upon subjection of the actuator to additional heat the thermalresponsive expansive material 44 expands. As best shownin FIGURE 3, the area'of the enclosing walls 36 is greater than the area of the cavity or bore within which the'rod- 40 is snugly slidably disposed. 'It has been found that when this ratio exists, i.e., in which the cross sectional area of the enclosing walls is equal to or greater than'ther area of the cavity withinth'e elastic body, a squeezing or extrusion action occurs during expansion of the material" 44, as shown'in FIGURE Z. 1 1 Therefore, the actuator rod 40 is squeezed from the cavity orbore 34, as'the'walls 36 move inwardly, as shown in FIGURE-2. This extrusion action or squeezing action is distinguished from'diaphragm action in that in dia-- phragm action the sealing-member follows the 'end offanactuator rod so that the bottom end of the sealing member remains or tends to remain in engagement with the endof the actuator rod as the actuator rod is forced in a direction from the container. During such diaphragm action stresses upon the sealing material are high.

Due to the fact that the actuator rod of this inven-' tion is squeezed or extrudedfrom within the bore 34 of the elastic'body 25, as shown in FIGURE 2, the walls; 36 move smoothly inwardly during expansion of the mate-'- rial 4-4." Thus, there are only small stresses'upon the walls I 25 bonded thereto, aidsinguiding the movement of the Patented Mar. 1 2, 1963 a 3 actuator rod 40 as the actuator rod 40 moves through the opening in the cover member 14. Of course, the pressures Within the container are very high during the extrusion action which is illustrated by FIGURE 2, these pressures being caused by expansion of the material 44. Therefore, forces upon the elastic material adjacent the opening through the cover member 14 are very high. Due to the fact that the edges of the inner and outer surfaces of the cover member 14 are arcuate, as shown by referencenumerals and 24, and due to the fact that the elastic body has a portion extending through the opening and along the neck 22, the per unit forces and stresses upon the elastic material adjacent the cover member 14 are reduced. The stresses upon the elastic material adjacent the opening through the cover member 14 are sufiiciently low so that there is little possibility of failure of the elastic material adjacent the opening through the cover member 14. Thus, the neck 22 with the elastic material adjacent thereto serves as an excellent guide and sealing means for movement of the actuator rod 40 through the opening in the cover member 14.

From the above discussion and the drawing it is to be understood that the thermal responsive actuator of this invention is capable of long life and has accuracy, dependability and consistency.

Although the preferred embodimentof the devicehas been described, it will be understood that within the purview of this invention various changes may be made in the form, details, proportion and arrangement of parts, the combination thereof and mode of operation, which generally stated consist in a device capable of carrying out the objects set forth, as disclosed and defined in the appended claims.

-Having thus described my invention, I claim:

1. In a thermal responsive actuator, a container provided with tan enclosing wall having an aperture therethrough, the aperture having an arcuate edge on the inside surface of the wall, a hollow neck attached to the outer surface of the wall and encompassing the apers ture, the neck having an inner surface and an outer sur-- face, a body of elastic material disposed withinthe container and extending from the container through the aperture in said wall, the body of elastic material being bonded'to the wall on the inside and outside thereof, the elastic material also being disposed on the inner and outer surfaces of the neck and bonded thereto, the body of elastic material having a wall member forming, a bore therein; the thickness of the-wa1l member within the neck being much less than the thickness of the wall member withinthe container, the bore being in the. portionsof the body of elastic material within the-neck and on both sidesof thewall, an actuator rod within the bore and reciprocally movable with respect to the wall, and a body ,ofthermal responsive work producing material within the container and exterior of the body of elastic material.

. body of'elastomeric material also-being bonded to said neck, thebody of'elastomeric material having a wall form- 'ing a bore therein'which extends through saidopening and through said neck, thethickness of the wall of the V portion ofthe bore'within the neck being muchiless than the" thickness of the wall forming the remainder of the bore; and a reciprocally movable rod member disposed withinsaid bore. j e e g r 3;. In a thermal responsive ac u or, avcon'tainer, the container having a wall provided with an opening therethrough, the wall having an inner surface and an outer 1 surface, the edge of the opening being ,arcuate at the 2,, In a thermal responsive actuator,-,a container pro r inner and outer surfaces of the wall, a body of elastic material bonded to the said wall, a main portion of the body of elastic material being within the container, an intermediate portion of said body of elastic material ex tending through said opening in 'the wall, an auxiliary portion of the body of elastic material being disposed on the outer sur'face of the wall and extending therefrom, the body of elastic material having wall members forming a bore therein which .extendsthrough the auxiliary and intermediate portions and intojthelma'in portion thereof, the thickness of the wall members forming the bore of the intermediate portion being much less than the thickness of the wall members forming the remainder of the bore, an actuator rod snugly disposed and reciprocally movable within the bore, and a body of thermal expansive material within the container exterior of the body of elastic material.

, 4. In an actuator device, a wall member having an elongated circular passage therethrough, a cylindrical 1 rod member extending through the'pa'ssage and recipro cally movable with respect to the'wall member, the di- 7 ameter of the rod member being considerably smaller than the diameter of the aperture so that a space exists between the rod member and the wall member,,the pas sage in the'wall member having an inner edge and an outer edge, both of the edges being arcuate, a body of elastomericnmaterial extending through the passage and encircling and engaging therod member and in engagement with opposite surfaces of the wall member, the thick ness dimension of the elastomeric material within the passage being considerably less than the thickness of the remainder of the body of elastomeric material. p

5. In a pressure responsive device, an enclosing wall having an opening therethrough, the enclosing wall hav ing opposed surfaces, an elastomeric sealing member having portions thereof in engagement with both surfaces of the enclosing wall, the sealing member also having an intermediate portion extending through the opening in the enclosing wall, the sealing member having an outer extending portion and an inner extending portion which extend from the enclosingjwali on opposite sides thereof, the elastomeric sealing member having wall members forming a cavity therein which extends through the intermediate portion and through the'outer extending :por-v tion of the elastomeric sealing member, and through a part of the innerextending portion, the thickness dimension of the wall members of, the cavity in the inter mediate portion being considerably less than the thick ness of the wall members forming the remainder of the cavity.

6. Ina thermal'responsive actuator, an enclosingwall provided with anuaperture therethrough, a neck integral with ,the'wall and encircling the aperture, the neckextending'from' the wall on one side thereof, theneckhav ing an outwardlyextending flange at the end thereof, a body of elastic material extending through the aperture, the body of elastic material also engagingthe wall and extending therefrom on opposite sides thereonthe body of elastic material having a cavity therein, a portion of .the cavity being within the-neck,'ian actuator rod disposedwithin the .cavity and reciprocally movable ,through the aperture in the wall, and thermal responsive means exterior ofai e' bodyof elasticmaterial.' j

.7. In ajthermal responsive actuator, a containerahav-, ing an enclosing wall, provided with an aperture therethrough, a neck exterior of the containenextending from the wall and integral therewith and-encompassing the aperture, an elastic body having a main portion within the container, the elastic body also, extending through the aperture and'through the neck and beyond the neck, the elastic body also having a portion onthe outer surface of the neck and onthe outer surface of the enclosing wall,

the elastic bodybeing bonded to the enclosing wall on both surfaces thereof, the elastic body having a bore therein extending through the neck and through the aperture and into the main portion of the elastic body, and actu ator means Within the cavity.

8. In a thermal responsive actuator a container having a portion provided with a neck forming an opening therethrough, the neck extending from the exterior of the container, a body of elastomeric material in bonded engagement with opposite sides of the Wall and with opposite sides of the neck, the body having wall members forming a cavity therein which extends through said neck, the cross sectional area of the portion of the wall members within the container being at least as great as the area of the cavity but the cross sectional area of the wall members which form the portion of the cavity extending through the neck being very small and much less than the area of the cavity.

9. In a pressure responsive actuator device, a rigid wall member provided with an aperture extending therethrough, the rigid Wall member having an inner surface and an outer surface, both of said surfaces being arcuate at the edge of the aperture, elastomeric material bonded to both of said surfaces of the rigid wall member and extending through the aperture, the elastomeric material having resilient wall members forming a bore therein, the bore extending through said aperture, the thickness dimention of the resilient wall members within the aperture being very small compared to the thickness dimension of the resilient wall members outside of the aperture, and a rod member slidably disposed within the bore.

References Cited in the file of this patent UNITED STATES PATENTS 1,873,590 James Aug. 23, 1923 1,873,592 James Aug. 23, 1923 1,926,197 Dun Sept. 12, 1933 2,507,466 De Craene May 9, 1950 2,517,717 Rose Aug. 8, 1950 2,699,357 Roth Jan. 11, 1955 2,806,376 Wood Sept. 17, 1957 2,875,452 1959 Portolano Mar. 3,

Claims (1)

1. IN A THERMAL RESPONSIVE ACTUATOR, A CONTAINER PROVIDED WITH AN ENCLOSING WALL HAVING AN APERTURE THERETHROUGH, THE APERTURE HAVING AN ARCUATE EDGE ON THE INSIDE SURFACE OF THE WALL, A HOLLOW NECK ATTACHED TO THE OUTER SURFACE OF THE WALL AND ENCOMPASSING THE APERTURE, THE NECK HAVING AN INNER SURFACE AND AN OUTER SURFACE, A BODY OF ELASTIC MATERIAL DISPOSED WITHIN THE CONTAINER AND EXTENDING FROM THE CONTAINER THROUGH THE APERTURE IN SAID WALL, THE BODY OF ELASTIC MATERIAL BEING BONDED TO THE WALL ON THE INSIDE AND OUTSIDE THEREOF, THE ELASTIC MATERIAL ALSO BEING DISPOSED ON THE INNER AND OUTER SURFACES OF THE NECK AND BONDED THERETO, THE BODY OF ELASTIC MATERIAL HAVING A WALL MEMBER FORMING A BORE THEREIN, THE THICKNESS OF THE WALL MEMBER WITHIN THE NECK BEING MUCH LESS THAN THE THICKNESS OF THE WALL MEMBER WITHIN THE CONTAINER, THE BORE BEING IN THE PORTIONS OF THE BODY OF ELASTIC MATERIAL WITHIN THE NECK AND ON BOTH SIDES OF THE WALL, AN ACTUATOR ROD WITHIN THE BORE AND RECIPROCALLY MOVABLE WITH RESPECT TO THE WALL, AND A BODY OF THERMAL RESPONSIVE WORK PRODUCING MATERIAL WITHIN THE CONTAINER AND EXTERIOR OF THE BODY OF ELASTIC MATERIAL.

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