US3549217A - Center plate lubricating device - Google Patents

Description

Dec. 22, 1970 w, WATSONv 3,549,217

CENTER PLATE LUBRICATING DEVICE Filed Nov. 29, 1968 u-- pn-apiip-nm---- 1''... 'IIDII'I.

, -q 2e 16 j Inventor William. R. Watson. 3 MmaaQ,W, Cavk & Enf- United States Patent 3,549,217 CENTER PLATE LUBRICATIN G DEVICE William R. Watson, Oak Lawn, Ill., assignor to Nalco Chemical Company, Chicago, 11]., a corporation of Delaware Filed Nov. 29, 1968, Ser. No. 779,885 Int. Cl. B61f 5/16 US. Cl. 308-137 5 Claims ABSTRACT OF THE DISCLOSURE A high strength, non-dusting center plate lubricating device which comprises a paper disc adapted to fit between a body bolster center plate and a truck bolster center plate. The paper disc is uniformly impregnated with -60% by weight of molybdenum disulfide.

INTRODUCTION The center plate assembly of a railroad car is part of the truck wheel frame assembly. The center plate assembly consist of two components. They are the body bolster center plate and the truck bolster center plate.

The truck bolster center plate is physically part of the truck wheel frame. More specifically, it is in the center of the frame member which is parallel to the railroad car wheel.

The body bolster center plate is the removable portion of the center plate assembly. It is adapted to fit on top of the truck bolster center plate.

The center plate assembly has a circular center opening adapted to fit a solid cylindrical pin. The pin is dimensioned to be in loose fitting relationship with the center openings of the center plate assembly.

Normally two trucks are used to carry one railroad car. The bottom surface of the railroad car which rides parallel to the ground is designed with two circular openings centrally located near the ends of the car. These openings are adapted to fit the cylindrical pin of the center plate.

The function of the center plate is to allow the swiveling of the truck portion of the railroad car when traveling on curved tracks.

The swiveling motion is allowed by the pivoting action of the center plate assembly. However, this pivoting action necessarily requires the movement of the surfaces of the body bolster plate and the truck bolster plate against one another. As a consequence, the contacting surfaces of the respective center plate portions require lubrication.

Inadequate lubrication will result in severe 'galling and undue frictional wear. Inadequate lubrication will also result in a restriction in the case of swiveling of the railroad car trucks. Such a restriction causes increased wheelflange wear, reduction of lateral thrust on journal bearings, increase in hot-boxes and probably most important non-uniform train resistance. Many substances have been applied to center plates in the hope of finding an adequate lubricant to minimize these problems.

Many of the common petroleum based greases have been tested. However, such greases have failed to provide adequate lubrication, even for short periods of time. These greases completely disappear from the center plate contact area after a short period of time. They are extruded over the rim of the truck center plate.

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Solid compounded lubricants have also been tested. The solid compounded lubricants appear to produce better results than the greases. However, the period of time for which they offer protection is relatively small.

Attempts have also been made to use graphite applied in a laquer carrier to a depth of 6" to the truck center plate. Experience with this type of lubrication system indicates that under extreme conditions of temperature and pressure the lacquer oxidizes and resinifies, thereby producing abrasive substance which counteracts the lubricity imparted by the graphite.

Thin plastic discs impregnated with either molybdenum disulfide or graphite afford lubrication to the center plate and prevent metal seizure. However, the discs themselves eventually disintegrate and portions are extruded over the rim of the center plate. The coatings afforded by these devices were not uniform in all cases.

Certain liners were also tested and proven unsatisfactory. Examples of such liner compositions are: High tensile bronze liners and phenolic laminated fabric liners, soft steel liners, and 325 Brinell liners. Their ability to provide adequate lubrication was marginal. They also caused dangerous conditions since sharp edges were formed which protruded form the center plate pin.

From the above, it maybe concluded that many schemes have been tested and proposed in an effort to afford adequate long life lubrication to center plate assemblies. Grease-like substances tend to be extruded from be tween the surfaces of the mating center plates, thereby depriving certain of the contact areas with a lubricant film. Greases and other devices or methods which have been used, while alfording short term lubrication, are not capable of impartinlg long term lubrication to the center plate assemblies. In other cases Where adequate lubrication is achieved, many of the devices are expensive and diflicult to manufacture, there-by making their use economically prohibitive.

It would be a great benefit to this art if an inexpensive yet effective device or lubricating system were available which could provide lubrication to center plate assemblies lasting for long periods of time at low cost. Such a device should be simple to manufacture and should be capable of installation or application without the need of special equipment or trained personnel. Another desirable feature for a lubricant or device would be a lubricant which possesses such characteristics as high shear strength, is non-dusting and would not tend to be extruded under conditions of normal usage.

OBJECTS It is, therefore, an object of this invention to provide a lubricating device specifically adaptable to lubricate center plates which exhibit the following properties: (1) providing long term lubrication, (2) high shear strength, and (3) non-dusting.

THE DRAWINGS For a more comprehensive understanding of the invention, reference may be had to the drawings of which:

FIG. 1 is a top view of the molybdenum disulfide impregnated paper disc.

FIG. 2 is a horizontal cross-sectional view taken across lines 22 of FIG. 1.

FIG. 3 is a horizontal cross-sectional view of a typical center plate assembly, containing the molybdenum disulfide impregnated paper disc of the invention.

With specific reference to the drawings, there is shown in FIGS. 1 and 2 a paper disc which contains uniformly distributed therethroughou-t molybdenum disulfide particles 12.

FIG. 3 illustrates a typical center plate assembly 14 which is composed of a body bolster plate 16 and a truck bolster plate 18.

The truck bolster plate 18 is in the form of a dish having sidewalls 20 and a flat bottom surface 22 which rnates with a corresponding face 24 of the body bolster plate 16.

Both the body bolster plate 16 and the truck bolster plate 18 contain in their center, mating hub assemblies 26 and 28 respectively which contain therein vertically positioned openings 30 and 31 which are adapted to receive a pin 32 in loose fitting relationship.

Pin 32 is adapted to engage an opening 33 located in the bottom of a typical railway car, a portion of which is designated generally by the numeral 34.

Positioned between flat bottom' surface 22 of truck bolster plate 18 and face 24 of body bolster plate 16 is the molybdenum disulfide paper impregnated disc 10. The weight of the mating faces 22 and 24 in conjunction with the horizontal rotation imparted thereto by the movement of railway car body 34 tend to disintegrate paper disc 10 and impart to matingfaces 22 and 24 a tenaciously bonded thin film of molybdenum disulfide. As will be shown later in the examples, the film of the molybdenum disulfide is characterized as being uniformly coated over the mating faces of the center plate assembly 14.

The relative dimensions of the center plate assemblies will vary with the normal load capacity which is to be carried. Table I shows the typical geometric dimensions of the center plate components as a function of load capacity.

THE INVENTION The invention is directed to a device and method adapted to provide long term lubrication for railway car center assemblies. Very simply, the invention comprises a disc .ofpaper uniformly impregnated with. from 10 to 60% by weight and preferably 20 to 40% by weight of finely divided molybdenum disulfide.

The diameter of the paper disc depends upon the diameter of the center plate assembly in which it is to be used. Generally center plate diameters vary between 12 and 16 inches depending on the nominal car capacities. As a consequence, the diameter of the paper disc of this invention will vary between 12 and 16 inches.

Typical thickness of the paper discs of this invention will vary from 0.001 to 0.5 inch in thickness.

THE MOLYBDENUM DISULFIDE COMPONENT coatings on metals are so adherent that they are not easily washed away and can provide long term lubrication even in a liquid surrounding. Molybdenum disulfide is stable in the normal atmosphere or in the absence of' oxygen over a wider temperature range than liquid lubricants, and is unaffected by extreme pressures both high and low. The lubricating action of dry molybdenum disulfide appears to be unafiected by temperatures from -40 to 700 F. Above 700 F. oxidation occurs in air, but under non-oxidizing conditions no change in structure occurs even after heating to 2350 F.

A preferred form of molybdenum disulfide which is used in this invention has a particle size range of from 0.1 to 500 microns. It should be understood, however,

that other particle sizes may be used.

THE PAPER COMPONENT The paper used to form the lubricating discs of the invention may be selected from any number of wellknown cellulosic fibric materials.

Either mechanical or chemical pulps may be used in preparing the discs. From the standpoint of ease of preparation, chemical pulp papers are preferred. These chemical pulp papers may be characterized as either being sulfite or sulfate [Kraft].

Of these two chemical pulps, the sulfite pulps, particularly bleached sulfite pulp papers represent the preferred cellulosic fibric materials from which the lubricating discs are prepared.

As will 'be shown in the examples, while the Kraft paper stocks may be used, thesedo not have the retentive characteristic of the bleached sulfite stocks for purposes of retaining within the interfiber interstices the particles of molybdenum disulfide.

For a more complete description of the papers described above, reference may be had to the Encyclopedia of Chemical Technology, John Wiley & Son, New York, First Edition.

The disc are prepared by adding 10 to 60% by weight of the molybdenum disulfide based on the weight of pulp to a slurry of highly beaten paper pulp. The paper pulp molybdenum disulfide mixture is then thoroughly mixed so that a uniform dispersion is obtained. The water is then drawn off by for example the application of vacuum and a moist mat containing uniformly distributed molybdenum disulfide is produced. This moist mat is pressed and dried to the appropriate specified thickness. The resulting product is a hard, molybdenum disulfide impregnated paper board which has high strength and is nondusting. This paper board can subsequently be brought to the proper diameter disc size. It is understood any conventional papermaking techniques can be used to prepare the discs.

To illustrate the preparation of'the discs, the following are presented by way of example.

EXAMPLES Example I A sample of a bleached, sulfite paper pulp was beaten in a laboratory blender until a freeness 50 seconds was obtained. This paper pulp consisted of 70% cellulose and 30% water. This paper pulp was osterized to break it up further and additional water was added to make a slurry consisting of 33%% by weight of paper pulp and 66 /s% by weight of water. About 30% by weight of molybdenum disulfide based on weight of pulp was added to the slurry andfurther osterized for a few minutes to niix it up. This molybdenum disulfide had a particle size of about 50 microns. The mixture was then put into a Buchner funnel to draw oif the water. The molybdenum disulfide stayed in the paper. The slurry, which was'now a moist mat, was then pressed and dried. The resulting product'was a hard moly-impregnated'paper board which was high strength and is non-dusting.

The efiluent water from the Buchner funnel had no molybdenum disulfide in it. This showed that the molybdenum disulfide was being retained by the paper. This example is the preferred technique of making the lubricant disc.

disc on the center plate, all of the center plates were inspected. The visual observations are listed in Table II.

TABLE II.CENTER PLATE LUBRIOATING DISC INVESTIGATION FINDINGS Disc Disc Molybdenum disulfide replaced replaced composition of paper alter 1 after 5 matrix disc month if months if- Condition observed after 1 year Test No.:

1 30% moly (203 oz. moly)- Lubrication satisfactory-one old gall. 2.. do Same as test No.1. 3.- do N 0 fresh galls-no evidence of disc lubrication good. 4. 20% moly (1.20 oz. moly) Contact areas well polishedsatislactory lubrication. 5.- moly (0.53 oz. moly)- Alter debris removed, Well lubricated. 6 .Jlo No Gal ssome cxtrusionlubrication Example 11 All the steps of Example I were followed except the paper stock was a bleachedKraft stock.

The efiluent Water from the Buchner funnel contained quantities of molybdenum disulfide. The paper pulp retained about one half of the molybdenum disulfide added. If this process was used to make this molybdenum disulfide paper disc, this water would have to be recirculated in order to recover the molybdenum disulfide. Therefore, although the Kraft paper pulp may be used, the sulfite paper pulp is preferred.

Example III A slurry of pulp comprising molybdenum disulfide was prepared as set forth in Example 1. After the pulp and molybdenum disulfide in it. This showed that the molybplaced into a special paper making tray which was circular in shape and 14" in diameter. Vertically positioned in the center of the tray was the hollow 3" diameter tube.

The pulp containing molybdenum disulfide was put into this special tray and allowed to drain until a wet mat was formed. This mat was then pressed, squeezed and dried in conventional laboratory paper making apparatus.

The finished molybdenum disulfide impregnated paper disc, as well as other similar paper discs were used in the tests more fully described hereinafter.

Example IV The same procedure as Example III was used except that the amount of molybdenum disulfide used was varied. The finished discs contained 10 to by weight of molybdenum disulfide respectively.

Example V In order to test the lubricating ability of the paper discs impregnated with molybdenum disulfide, the completed discs were placed between the faces of a center plate assembly of freight cars. The cars were then used in normal railroad service. The discs tested contained 10%, 20% and by weight of molybdenum disulfide.

After one month, one of the paper discs containing 30% molybdenum disulfide, was replaced. After five months, all of the paper discs were replaced. After replacing the discs, the center plate faces were again placed in contact.

CONCLUSIONS All of the center plates were satisfactorily lubricated. There were no fresh galls. The original galls were somewhat healed.

The results in Table II show that the amount of molybdenum disulfide required for satisfactory lubrication is appreciably less than 2 ounces. The paper matrix disc were very satisfactory, giving equal distribution of molybdenum disulfide and supplying sufiicient sliding action for proper lubrication. The effects of the molybdenum disulfide are accumulative. The lubrication is better after three applications than two or a single application.

What is claimed is: I

1. In a railway truck, means for lubricating the truck center plates comprising a disc of paper having the approximate dimensions of said center plates and having uniformly distributed there throughout from 10 to 60% by weight of finely divided molybdenum disulfide.

2. The device of claim 1 where the paper disc is a sulfite paper disc.

3. The device of claim 1 where the paper disc is from 0.001 to 0.5 in thickness and contains from 20 to 40% by weight of molybdenum disulfide.

4. The device of claim 1 where the molybdenum disulfide has an average particle size range of from 0.1 to 500 microns.

5. The device of claim 2 where the paper disc is a bleached sulfite paper disc.

References Cited UNITED STATES PATENTS 1,235,475 7/1917 Hickman 184-1X 2,219,054 10/1940 Palm et a1. 308-L(UX) 3,000,846 9/1961 rRunton et al 252-12.6X 3,127,346 3/1964 Oliver et a1. 184-1X 2,514,034 7/1950 Dean -199 2,960,352 11/1960 Wood 308-137X 3,170,740 2/1965 Smith 308-137 3,466,102 9/1969 Goodwyn 308-137 FOREIGN PATENTS 622,742 6/1961 Canada 308-L(UX) MANUEL A. ANTONAKAS, Primary Examiner US. Cl. X. R.

2 3 3 UNITED STATES PATENT OFFICE CERTIFICATE 01* CORRECTION Patent No. 3, 5M9, 217 Dated December 22, lqjO 1nventor(s) William R. Watson It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, before line 1, insert After one year from the original placing of the paper Signed and sealed this 23rd day of March 1 971 (SEAL) Attest:

EDWARD M.F'LETGHER,JR. WILLIAM E. SCHUYLER, J Attesting Officer Commissioner of Patent:

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