US3288369A - Rail joint - Google Patents

Description

Nov. 29, 1966 L. GROFF 3,

RAIL JOINT Filed June 18, 1965 5 Sheets-Sheet 1 FIG. 1.

INVENTOR EMORY L. GEOFF ATTORNEY E. L. GROFF RAIL JOINT Nov. 29, 1966 5 Sheets-Sheet 2 Filed June 18, 1965 FIG. 8.

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H r l d Y A INVENTOR EMORY L. GROFF BY a H l f ATTORNEY E. L. GROFF RAIL JOINT Nov. 29, 1966 5 Sheets-Sheet :5

Filed June 18, 1965 INVENTOR EMORY GROFF M 4 A 'ORNEY United States ?atent 3,288,369 RAIL JOINT Emory L. Grotf, Pompano Beach, Fla, assignor, hy mesne.

assignments, to Poor & Company, Chicago, 11L, a corporatnon of Delaware Filed June 18, 1965, Ser. No. 464,952; 6 Qlaims. (Cl. 238243) This invention relates to rail joints for connecting the ends of rail sections to form a railroad track. More particularly, the invention relates to so-called oint bars of non-metallic material having generally universal use. Heretofore, it has been customary to manufacture these bars of high grade steel at a rolling mill in steel plants located at strategic shipment points because of'the distance of the point of use from the mill. That 1s to say, under current practice, joint bars are burdened not only with the great expense of making and maintainmg many sets of rolls but also great tonnage transporta tron costs.

On the question of weight, for example, a single socalled 131# metal bar to fit a 13l# rail is twenty-four inches in length, with four bolt holes, and would weigh approximately 83#; and, a single thirty-six inch bar, with six bolt holes, would weight approximately 124#. With two bars to the joint, the dead weight becomes enormous.

Moreover, in the event the bars are used in sections of signal track, the block signal divisions require intervals of insulated joints. Thus, two separate and distinct classes of joint bars must now be manufactured and made available, whereas, with the present invention, the bars in themselves are non-conductive and may be used with a standard insulated end post to provide an insulated joint while the rails between insulated joints using the bars of the present invention may be made conductive with a metallic end post such as shown in FIG. 2 of Patent No. 3,111,264 issued November 19, 1963.

Rail joint bars are in efiect a beam, intended to grip the rail ends with sufiicient force to simulate a continuous rail. It has now been established that continuous rail has many objections, even when made in-situ, and jointed track has advantages quite clear to railway maintenance of way engineers.

Accordingly, a primary object of the invention is to provide a non-metallic relatively light-weight joint bar capable of being produced by molding techniques suitable for use in track. Preferably, the bars are made of a moldable plastic material such as glass fibers enveloped or coated with a thermosetting resin. In that connection,

since the greatest concentration of pressure is longitudinally along the center of the web at the bolt holes, this area is the focal point from which pressure is transmitted to the head and foot to insure proper fit and rail end support. To that end, it is proposed to make rail joint bars wholly of thermosetting resins'utilizing glass rovings or strands wound about a matrix or core which remains as a part of the finished bar. Thus, the present invention contemplates a joint pre-molded to fit the fishing of any given steel rail section having compressive strength commensurate with a steel bar. The advantages attendant to such an advancement in the art are numerous, the most important of which are the overall economical aspects. In the case of steel bars, it is necessary, as previously indicated, to provide and maintain rolls, shears, ovens, dies and tools as well as other heavy equipment, all operated by high-wage personnel, while only a fraction of this effort is required for manufacturing the present plastic bar. Moreover, the cost of storing and shipping is far less for the plastic bar which weighs approximately one-fifth of the amount of the steel bar.

Patented Nov. 29, 1966 An important use for a rail joint of plastic would be in connection with the recently introduced electronically controlled rail systems wherein a single operator sitting at a control panel automatically controls several unmanned trains operating over a single rail net, for example between two distant points as in inter-urban traffie or ani ron-ore mine complex where a punch card control system'now is in operation. In such a system, electrical impulses are transmitted through the rails to con trol the different locomotive engines at several different speeds and to regulate the braking controls. The use of steel bars without adequate insulation would interfere with the maintenance of the critical electronic circuits being transmitted through the rails, contrary to the plastic bar which is a non-conductive, non-magnetic, and non-corrosive element.

Accordingly, the principal objects are to provide a reinforced plastic joint bar having a filler material arranged to provide maximum compressive strength in specified areas; provide a method for manufacturing joint bars of plastic material; and also to provide a method for the manufacture of plastic bars having a filler of reinforcing material.

With these and other objects in view which will more readily appear as the nature of the invention is better understood, the invention consists in the novel construction, combination, and arrangement of parts hereinafter more fully described, illustrated, and claimed.

A preferred and practical embodiment of the invention is shown in the accompanying drawings, in which:

FIG. 1 is an end elevation of one form of a typical plastic rail joint ba-r according to the present invention as it is applied to the fishing of the rail.

FIG. 2 is a side elevation of the bar shown in FIG. 1.

FIG. 3 is a vertical cross-sectional view taken on the line 33 of FIG. 2.

FIG. 4 is a fragmentary side elevation of the matrix about which the reinforcing strands are wound.

FIG. 5 is a vertical cross-sectional view taken on the line 55 of FIG. 4.

FIG. 6 is an elevation of another form of matrix.

FIG. 7 is a cross-sectional view taken on the line 7-7 of FIG. 6.

FIGS. 8 and 9 are fragmentary elevations of typical reinforcements to be embodied in the web of the bar.

FIG. 10 is a diagrammatic perspective view of one form of matrix encased in a body of reinforced plastic prior to being placed in the mold.

FIG. 11 is a cross-sectional view of the mold contaming the body of FIG. 10.

FIG. 12 is an end elevation of a modified form of bar fitted to a rail.

FIG. 13 is a side elevation of the bar shown in FIG. 12.

FIG. 14 is an end sectional view of a plastic bar having metal cladding applied thereto.

FIG. 15 is a side elevation of the bar of FIG. 14.

Similar reference characters designate corresponding parts throughout the several figures of the drawings.

Referring to the drawings, it will be seen'that the present invention is directed to a plastic joint bar B, such for example as a head-free bar adapted to fit into the fishing space of a rail R. Currently, bars of this type are made in a rolling mill, and in the example illustrated the bar has the shape of a standard 131-RE rail. It will of course be understood that this bar is used solely for purpose of illustration, and not by way of limitation.

The present rail joint bar is constructed generally of a synthetic plastic resin. Synthetic resins fall into two basic classifications; namely, thermoplastic and thermosetting. thermosetting resin is the desirable type of material for the present device in preference to the use of thermoplastic resins, since the latter are long chain compounds which soften upon the application of heat.

As thermoplastic compounds undergo no chemical changes and can be heated and cooled any number of times without change, they find little use in many structural applications, since they have limited resistance to heat and are subject to cold flow under load.

Accordingly, in the present invention, thermosetting resins are the most desirable compounds. The basic property of thermosetting resins is to change under heat by polymerization to form infusable cross-linked compounds. Many of these compounds require heat to complete the reaction, but others, for example the epoxies, are exothermic reactions and the heat is purely an accelerator to increase the speed of the reaction and to increase the permissible operating temperature of the resultant joint bar when put into service. Thus, the thermosetting epoxy resins are the preferred compounds for use in producing the present invention in view of their inherent properties. Such compounds include the epoxy-phenolics, epoxypolyamides, epoxy-polysulphides, etc.

Even though the above resins appear to be the most suitable, numerous phenolic polyester, polycarbonate, polytrifluoroethylene, silicone, and phenol silane compounds cannot be ignored; however, the present description will be confined to the discussion of a rail joint bar constructed of the epoxy type of synthetic resins.

The most desirable reinforcing can be provided by utilizing a structural filler in the nature of glass strands more commonly referred to as glass fibers or roving. Numerous glass fiber reinforced epoxy resin compounds are available from commercial chemical concerns which may be utilized in the present invention. These plastic impregnated fibers or roving, generally referred to as glass filled epoxics, are usually supplied on spools ready for use by the manufacturer. The most common use heretofore for this product has been for use in filament winding by the electrical industry and for pressure vessels, rocket cases, tubular and tank type structures. Any suitable type of glass reinforcing strands or roving may be used in combination with any of various compounds of epoxy resins. For maximum strength, a ratio by weight of approximately 70% glass roving to 30% epoxy resin is recommended.

A typical composition for the glass roving may be, for example: silicone dioxide, 26 percent; aluminum oxide, 64 percent; magnesium oxide, percent. Such a composition provides a low alkali magnesia alumina silicate glass of extremely high tensile strength. When combined with any selected epoxy resins, this glass filled epoxy has been tested to indicate a tensile strength on the order of 450,- 000 p.s.i. The above described glass filler is merely an example of one composition which may be employed in carrying out the present invention as numerous other rovings may also be used composed of high strength specialty glass, high modules glass, or quartz fibers.

Mechanical damage is the sole factor having any significant effect on the strength of a glass fiber reinforced plastic rail joint bar, while on the other hand a steel rail joint bar is also affected by time, static load, cold flow, exposure to the elements, annealing, stress corrosion and cracking, and crack propagation. In order to utilize to a maximum advantage the inherent strength of a glass fiber reinforced epoxy resin in connection with the formation of a rail joint bar, a novel method has been devised whereby the epoxy resin impregnated roving is arranged in a particular manner prior to curing to produce the final rail joint bar.

The bolt holes in the joint bar are, as previously indicated, customarily located in the zone of the horizontal neutral axis of the bar and the force of the bolts against the web of the bar firmly clamps it to the head and base of the rail. Thus, the head and base of the rail correspond generally to the top and bottom flanges of a beam and as usual the upper portion of the bar is in compression while the bottom of the bar is in tension.

For the sake of simplicity in carrying the invention into effect, it is proposed to provide a matrix or core M or M of the type generally shown in FIGS. 4-7 of the drawings.

The matrix M may be of any suitable cross-sectional shape, but those shown in FIGS. 4-6 may be considered typical.

According to FIG. 4, the matrix M includes a center member 10 of substantially the length and height of the bar specifications. The member 10 is flanked by side members 11 at opposite faces thereof and which may have the outwardly curved edge flange portions 12. Also the central horizontal portion of the matrix is provided with thimbles T to facilitate the making of holes to receive the bolts in the finished product.

According to FIG. 6, the matrix M may consist of separate longitudinally divided and mating sections 13 and 14 which receive the thimbles T between them. To ensure quick registry of the half-sections of the thimbles, the adjacent edge portions of the sections 13 and 14 may be provided with suitable interlocking portions 15.

FIGS. 8 and 9 illustrate flat circular bolt hole reinforcing discs 16 and cruciform reinforcing members 17. These elements 16 and 17 may be used alone or in conjunction with the primary matrix M. Preferably, these members are stamped out of commercially available sheet material impregnated with an epoxy resin now sold in dry form and then activated chemically to become a part of the entire synthetic resin assembly.

FIGS. 12 and 13 show a bar whose web is relatively thick as compared with the web of other bars shown. A joint bar preferably does not fit the profile of the fishing of the rail precisely so as to provide take-up for wear and to insure maximum clamping effect. In the case of headfree bars, the latter engage the head-web fillet of the rail at the top while the bottom does not engage the base web fillet, but slidably engages the inclined upper face of the rail base. Thus, when bolt pressure is applied the base of the bar slides up the rail base and the head firmly engages the rail fillet.

FIGS. 14 and 15 show how the non-metallic bars may be readily applied with a metal cladding such for example as shown in Lansing Patent No. 2,702,161 dated February 15, 1955. This cladding may be applied by placing the same in the mold at the time of manufacture or may be applied before installation. In the patent, referred to, the metal pieces extend throughout the length of the bars and may be used with the bars of the present case, or alternatively, they may be medially spaced to provide a gap for the purposes described in Lansing Patent No. 2,989,240 dated June 20, 1961.

In the process of manufacture, the matrix M is placed in a jig so that the epoxy resin roving or strand 20 may be wrapped around and about the matrix as illustrated in FIG. 10. These strands may be wound about the matrix longitudinally, as shown, or transversely, according to the specifications of the bar. Moreover, the strands may be crossed in the form of a grid, and also diagonally at desired portions of the bar.

In order to secure maximum longitudinal rigidity in the bar the strands may be wound longitudinally of the bar with the intermediate strands passing around the thimbles T in a continuous figure-8 pattern from one end of the bar to the other. In other words, a strand thus wound would pass around say, the bottom of one thimble, and then cross over to pass around the top of the next adjacent thimble and so on to the opposite end of the bar.

Thereafter, the epoxy winding and its matrix may be placed in a mold as shown for example in FIG. 11. This mold preferably includes upper and lower sections 22 and 23 whose complementary sections are formed with the profile of the bar intended to fit in the rail fishing. Also the member 23 preferably has the bolt hole forming projections 24 which extend from the lower half of the mold into the upper half. This upper half is provided with a cavity 25 which conforms to the outer profile of the bar which receives pressure of the bolts.

After the desired number of windings of the strand material have been made on the matrix according to the desired size of the joint bar, the mold assembly is cured by heating. Many of the thermoplastic resins may be cured by means of a single heat, While others may require a post-cure in order to achieve maximum physical properties. An exemplary cure cycle which may be used in the formation of the present rail joint bar when produced with epoxy resin designated EP 787, as produced by U.S. Polymeric Chemicals, Inc., is as follows:

Cure cycle-l hour at 180200 F. Post Cure-1 hour at 250-300 F.

After the appropriate curing has been achieved and the joint bar removed from the mold, it is ready for immediate use, although some epoxy resins may increase in strength for about 21 days after curing and therefore should be stored for this period.

By way of further illustrating the range of the invention, reference may be made to FIGS. 12, 13 and 14.

In FIGS. 13 and 14, the bar B is substantially in the form of a solid rectangle having the rail fishing engaging surfaces 27 and 28 with a flat outer face 29 lying substantially in a plane intersecting the head and foot of the bar, thus providing a web 30 of relatively great thickness to receive the pressure of the bolts to be transmitted to the head and foot.

In FIGS. 14 and 15, the bar B2 is of a cross section substantially like that of FIG. 1 but having upper spaced cladding strips 31 and 32 for the head, and lower spaced cladding strips or shims 33 and 34 at the foot of the bar.

Referring further to FIGS. 14 and 15, it is pointed out that the steel shims or cladding may be readily used with an electrically insulating dimensionally stable thermosetting resin such as epoxy resin, because both in a composite structure follow Hookes Law. The epoxy resins have substantially a coefficient of expansion value sufficiently close enough to the coefficient of expansion value of the steel utilized, and, likewise, have a modulus of elasticity value comparable to that of steel, and said modulus of elasticity can be determined in the same manner as the modulus of elasticity value of steel with respect to the completed insulated joint. Moreover, since the insulated joint including the component parts of the invention are used under all conditions of heat and moisture, the components thereof must not only follow Hookes Law but they must also have substantially close enough and similar co-eflicients of expansion and contraction. Of course, the electrically insulating resin material is dimensionally stable when static and dynamic loads are imposed thereon.

I claim:

1. A nonmetallic rail joint bar including head and base portions connected by a web, said web comprising, an elongated core including an intermediate resin impregnated strip having other strips at opposite sides thereof and whose top and bottom edges turn outwardly, and longitudinally disposed strands of glass fibers impregnated with a thermosetting resin extending from end to end thereof and about said edges, and also having openings in the web spaced to receive the shank of a bolt.

2. A non-metallic rail joint bar according to claim 1, including, discs of reinforcing material having openings registering with the bolt hole openings in the intermediate portion of said core.

3. A non-metallic rail joint bar according to claim 1, wherein, cruciform reinforcing members are embedded in the web at the location of the bolt holes.

4. A non-metallic rail joint bar according to claim 1, including, annular insulating thimbles embedded in said webs and projecting laterally from the core to receive the joint bolts.

5. A rail joint bar comprising, a body including head and base portions connected by a web, said body provided with a vertically extending resin impregnated core whose top and bottom edges project into said head and base portions respectively, a plurality of longitudinally disposed strands of glass fibers impregnated with a thermo-setting resin extending from end to end of said body and about said edges to completely envelope said core, and said body also having a plurality of spaced apart openings through the web thereof to receive the shank of a bolt.

6. A rail joint bar according to claim 5, wherein, said core is longitudinally divided along a line passing through said openings and each divided portion includes interlocking mating edges.

References Cited by the Examiner UNITED STATES PATENTS 2,670,136 2/1954 Moses 238- 3,056,706 10/ 1962 Knoppel 52309 3,186,866 6/1965 Claeys l6l93 FOREIGN PATENTS 919,547 2/1963 Great Britain.

ARTHUR L. LA POINT, Primary Examiner.

R. A. BERTSCH, Assistant Examiner.

Claims (1)

1. A NON-METALLIC RAIL JOINT BAR INCLUDING HEAD AND BASE PORTIONS CONNECTED BY A WEB, SAID WEB COMPRISNG, AN ELONGATED CORE INCLUDING AN INTERMEDIATE RESIN IMPREGNATED STRIP HAVING OTHER STRIPS AT OPPOSITE SIDES THEREOF AND WHOSE TOP AND BOTTOM EDGES TURN OUTWARDLY, AND LONGITUDINALLY DISPOSED STRANDS OF GLASS FIBERS IMPREGNATED WITH A THERMOSETTING RESIN EXTENDING FROM END TO END THEREOF AND ABOUT SAID EDGES, AND ALSO HAVING OPENINGS IN THE WEB SPACED TO RECEIVE THE SHANK OF A BOLT.

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