US2692731A - Thermostat for internal-combustion engines - Google Patents

Description

Ot. 26, 1954 F. P, FARRAR THERMOSTAT FOR INTERNAL-COMBUSTION ENGINES Filed Dec. 27 1951 INVENTQR. 705m Z?. P czmar wpa@ UNITED STATES PATENT DFFICE THERMOSTAT FOR IN TER-N AL- COMBUSTION ENGINES `lohn F. P. Farrar, Maywood, Ill., assignor to Chicago Metal Hose Corporation, Maywood, Ill., a corporation of Illinois Application December 27, 1951, Serial No. 263,549

2 Claims.

This invention relates to thermostats for internal combustion engines, and concerns particularly thermostats adapted for mass production, for volume distribution, and sale.

Internal combustion engine thermostats, of the type commonly employed in automobiles and the like, present certain problems due to the cost considerations involved, and due to the necessity for reliable operation with a minimum of maintenance Iand care. These devices are produced in large quantities and sold at a relatively low cost. It is accordingly highly desirable that the fabrication be eected with a minimum amount of material, so arranged as to impart maximum strength to the unit in respect to the amount oi material used. It is further desirable that the arrangement of parts be such that the units may be mass produced, in their fabrication and assembly, with minimum likelihood that manufacturing tolerances and the like will impair the desired operating characteristics.

In accordance with the present invention a thermostat structure is provided, adapted for low cost mass production, having a maximum strength and rigidity in respect to the material used, and which exhibits improved operating characteristics when installed, with a minimum of maintenance or repair.

It is accordingly an object of the present invention to provide a thermostat for internal combustion engines, of low cost and of improved construction and operating characteristics.

More specifically stated, it is an object of the present invention to provide an improved thermostat, for automobiles and the like, which can be mass produced at minimum cost but with mass accuracy; which has improved strength; and which operates more smoothly and with minimum probability of freezing or binding in service.

A further object of the invention is to provide an improved thermostat, of the type delined. which has improved ow characteristics, and which is less subject to twisting and vibration and fatigue, when used either with rigidly or loosely mounted engines, and which is thus more durable and long lived in service.

Various specic advantages, features and objects of the invention will be apparent from the following specification, when taken in connection with the accompanying drawings, wherein a preferred embodiment is set forth for purposes of illustration.

In the drawings, wherein like reference numerals refer to like parts throughout- Fig. 1 is an assembly view, in vertical section, taken as indicated by the line l--l of Fig. 2, of a thermostat structure constructed in accordance with and embodying the principles of the present invention;

Fig. 2 is a side elevational view of the thermostat of Fig. 1, and with the open position of the valve being illustrated in dotted lines;

Fig. 3 is an enlarged plan view of the thermou stat shown in Figs. 1 and 2;

Fig. 4 is a detail sectional view of the valve, valve seat, and associated parts, of the structural assembly; and

Fig. 5 is a perspective detail view of the valve seat, stem guide, and associated parts,

Referring more specically to the drawings, the thermostat structure illustrated comprises a casing Ill having an outwardly directed flange portion I2, the peripheral shaping and character of which are in accordance with the particular constructional requirements of the engine with which the thermostat is to be associated.

The casing carries a U-shaped thermostat strap, said strap comprising a pair of legs lll and it connected at their lower ends by a platform porion I8, the latter forming a support for the thermostat bellows, indicated at 25J. Preferably the strap legs I4 and I6 are provided with reinforcing ribs, as indicated at 22. The upper portions of the straps or legs are widened as shown at 23, for increased stability and strength, and the extreme upper ends of the legs are reduced to provide shoulders which are staked to the main support casing as indicated, respectively, at 24 and 26.

More specifically, the platform portion It of the bellows support strap is provided with a circular channel 2B, as shown, which channel forms a receiving and centering recess for the lower open end of the cup-like bellows, and also forms a channel for the reception of solder or the like into which the bellows end may be hermetically sealed, as indicated at 3l) in the structure shown.

The upper plate 32 of the bellows is suitably secured to a valve stem 34, the latter providing a central passage 36 communicating with the interior of the bellows. As Will be understood by those familiar with devices of the type in question, the bellows may be lled with thermally responsive fluid, by means of the passage 3E, after which a ball 38 is driven into the passage, `to seal the same, and the ball in turn physically and hermetically sealed in position by soldering as indicated at 40.

The valve stem 34 is externally threaded at its upper end, and threadedly carries a valve member 42; the latter, after threaded adjustment to the proper position, being locked from inadvertent rotation by further soldering of the parts as indicated at 44.

The valve is of a cross sectional shape, as best shown in Fig. 1, for maximum strength, and to provide a relatively fiat outer ange portion 46 cooperable with an upstanding ange portion 48 of the main casing member, the latter forming a valve seat 49. The valve 42 is preferably formed with a leakage opening 5U, Fig. 3, of predetermined size, asis conventional instructures of the type set forth. l

As best shown in Figs. 3, 4 and 5, the upstanding flange 48 of the casing is provided at one diametrical point with a cross web or bar portion 52, the central portionofwhich is perforated and formed downwardly as indicated at 54, providing a guide for the valve stem 34 in its movements. It will be seen that the web or bar `portion 52 of the casing is formed integrally with the valve seat 49, the web thus forming an integral extension at the diametrical rpoints indicated which points are disposed along a diametral portion at substantially right 4angles to the dametral positioning of the bellows supporting strap so that resistance to tilting of the valve stem is at spaced diametrically opposed points. The arms of the cross web are preferably provided with reinforcing ribs as indicated at 56, which together with the general dished shaping of the cross web, and the downturned flange 54 of appreciable eX- tent, provides a rigid and rm cross web support. If desired, the flange 54 may act as a limit stop for the opening movement of the valve, the flange for this purpose being arranged to engage a suitable shoulder portion -58 vformed on the valve stem.

It will be noted that the casing member I2 may be, and is in the embodiment shown, a relatively simple plate member of light gauge. It has been found that the upstanding flange 48 together with the integrally formedstem guide 52-54, provides a reinforcing and rigidifying structure for the casing, so that notwithstanding the relatively light gauge and simplicity -of the casing, a warp and vibration resistant structure of adequate strength is provided. The downward projection of the stem guide'parts or arms 52, in combination with the upstanding flange 48, brings the stem guide part 54 substantially into the plane of the casing lf2 so that it may readily be used as a stop for the upward limit of travel of the bellows; and so that the stem guide 5'4 .may -be spaced downwardly somewhat from `the upper rend of the stem to improved the guidingaction.' The upstanding ange 48, together with the dishedlike stem guide, also provides an improved path for the uid flow upwardly through the structure, providing a minimum of turbulence on the approach side of the valve.

In combination with the foregoing structures, it will further be -noted that the -bellows support comprises a .simple 'U-strap hung vfrom the plate I2, further minimizing the required metal for lthe structure; the contour and shaping of the casing in the vicinity vof the -valve stem, as above described, imparting sufficient rigidity and balance to the structureso -that a simple `bellows support strap may be employed. The arms 22 of the support 'strap are :imper-forate at .their upper ends, whereas the perforations provided through the casing i2, due to the shaping heretofore mentioned, `do not unduly weaken the support structure.

The integral stem guide, whereinthe guide projects downwardly from the upstanding ycasing flange 48, provides a complete band "portion 54 encompassing the valve stem, which band portion is accurately positioned in respect to the casing, providing for the accurate positioning of the valve 42 in respect to its seat. The arrangement also precludes'the valve and valve stem from nuttering movement eliminating theY necessity for 4 vibration damper holding clips and the like, applied to the bellows. i

As will be understood, in the operation of the structure the plate l2 is mounted in the engine cooling water passage to be controlled, the cooling water passing upwardly through the valve under -control of 'the thermostat, in the usual manner. Thus, the mounted plate portion I2 in the particular installation constitutes a strong supporting area vand the location of the juncture between the support arms 52 and the stem guide 54 .substantially in the plane of the plate portion further assists in reducing any tendency of the guide or stem to tilt during operation.

It is obvious that various changes may be made in the .specific embodiment Yset forth without fdeparting from the spirit of the invention. The invention is accordingly not to be .limited to the particular structures shown and described, but only as indicated in the following claims.

The invention is hereby claimed as follows:

1. A thermostat assembly 4for .internal combustion engines, and comprising a support structure of thin gauge `material and of generallyskeleton form and including a plate portion having an upstanding annular flange form-ing a fluid passage with the upper edge thereof rounded inwardly and `downwardly to` provide a valve seat of rounded cross section presenting line Contact for a valve, a U-Shaped strap vhaving the upper ends of the arms thereof lsecured to said :support structure adjacent the -lower 'margin of said upstanding flange, a thermostatic bellows supported within said strap, `a valve disc having a marginal portion engageable in line contact with said valve seat and an inner depressed annular portion of rounded cross section generally complementing the adjacent rounded surface of said valve seat to improve fluid -iflow characteristicstherebetween, a valve stem interconnecting `said valve disc and the bellows, .a guide for the vvalve stem comprising a sleeve of appreciable axial extent vengaging the valve stem with a close sliding fit to stabilize the stem against tilting'on its axis, a pair of arms integral with the :rounded `upper edge of said upstanding flange and with said guide sleeve and inclined downwardly from said flange to `support and position the guide sleeve with the edge thereof which is adjacent the valve `disc spaced there-k below to .prevent any mutual abutment and assure tight sealing between the valve-seat and valve .disc upon any inward flexure thereof Aon closing, :and said arms extending along a ydiametral ,portion of said upstanding flange at substantially vright angles :to the diametral positioning of` the arms of the U-shaped strap for additionally .resisting tendency of the valve stem to tilt during opera-v tion.

2. A thermostat assembly as claimed incla'im l, wherein .the guide -sleeve is joined to `the support arms substantially in lthe plane of the plate por# tion for increased rigidity in the installed assembly.

References Cited in the file of this patent UNITED STATES PATENTS Number -Name i .Date Re. 17,228 Levyl Mar. 5, 1929 `908,138 Ricksecker Dec.l 29, -1908 1,667,207 Kinnard Apr. 24:, 1928 1,844,488 Ward Feb. 9, 1-932 2,126,498 Paton Aug, .9, .1938 2,263,100 Payne Nov. .18, 1941 2,578,141 Marette Dec. ,'11, '1951

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