US3048414A - Journal box dust guard - Google Patents

Description

Aug. 7, 1962 E. s. PEARCE ETAL JOURNAL BOX DUST GUARD Filed April 13, 1959 m w. mmwm w MHYO 0 E r 1 n NM Wm M/ United States Patent Office 3,048,4l4. Patented Aug. 7, 1962 3,048,414 JOURNAL BOX DUST GUARD Edwin S. Pearce, Leslie G. Taylor, and Thomas R. Booth,

Indianapolis, Ind., assignors to Railway Service and Supply Corporation, Indianapolis, Ind., a corporation of Indiana Filed Apr. 13, 1959, Ser. No. 805,751 6 Claims. (Cl. 277-430) This invention relates to dust guards for the journal boxes of railway cars. In the conventional journal-box construction, the axle projects into the journal box through an opening in the rear wall of the journal box, which opening is substantially larger than the axle in order to permit relative movement both horizontally and vertically of the journal box and journal. To prevent dirt from entering the journal box through such opening, it is customary to provide a dust guard which closely surrounds the axle and which is received in a cavity formed in the rear wall of the journal box. As such guards seat against unfinished surfaces on the journal box, the matter of providing an effective seal against the entrance of dirt presents a problem. Moreover, the necessity for accommodating for relative movement of the axle and the journal box usually involves movement of the dust guard in the journal box and, in so moving, the dust guard pumps oil out of the journal box.

It is an object of the invention to provide an improved dust guard which will effectively inhibit the passage of dirt into the journal box, which will not interfere with or be damaged by relative movement of the axle and journal box, and which will not act in operation to pump oil from the journal box.

Our improved dust guard comprises a pad of foamed, oil-resistant elastomeric material adapted to be received in the conventional dust-guard cavity of the journal box and provided with an opening which snugly receives the axle. Surrounding such opening on both faces of the guard are plate-like elements of rigid, preferably nonmetallic material. The thickness of the guard is'such that its pad will be compressed when introduced into the guard-receiving cavity of the journal box. An important charactertistic of our dust guard is that the elastomeric material forming the pad is not of uniform compressibility throughout its thickness. Conveniently, the pad is formed of two layers of elastomeric materials of different compressibility, and the guard is so positioned in respect to the journal box that the material of lesser compressibility is located adjacent the interior of the journal box. We have found that the use of a pad so constructed and arranged relative to the journal box practically eliminates all pumping of oil from the journal box.

Further objects and features of the invention will be come apparent from the more detailed description which follows and from the accompanying drawings, in which:

FIG. 1 is an isometric view of a complete dust guard;

FIG. 2 is a vertical section through a journal box showing the dust guard in position;

FIG. 3 is a fragmental section on the line 3-3 of FIG. 2; and

FIG. 4 is a fragmental section through the dust guard showing in full lines the form it assumes when positioned in the journal box and, in dotted lines, the form it assumes when in unstressed condition.

The journal box construction illustrated in FIG. 2 is more or less conventional. The journal box is provided with the brass 11 and wedge 12 through which the load is transmitted to the journal 13 of a railway car axle 14. The rear wall 15 of the journal box, or that wall nearest the wheel, has an opening 16 which receives with considerable clearance a machined collar 17 on the axle 14 and is also provided with a cavity 18 adapted to receive a plate-like dust guard which closely surrounds the collar 17.

The improved dust guard which is illustrated in its entirety in FIG. 1, comprises a compressible pad made up of two layers 21 and 22 of foamed oil-resistant elastomer, preferably of approximately equal thickness. The two layers 21 and 22 are cemented together through out their extent and have an exterior form adapting them for a snug reception within the cavity 181 of the journal box. Both layers are provided with registering holes 23 adapted to snugly receive the collar 17. On each face of the resilient pad is a plate 24, conveniently of nonmetallic material, provided with a central opening 25 somewhat larger than the opening 23 in the resilient pad. The plates 24 desirably have the same general shape as the pad 21-22 but are smaller than the pad to leave the marginal portions of the pad projecting outwardly beyond the margins of the plates. The plates are held in position on the pad by cementing them thereto preferably over their entire extent.

The overall thickness of the pad 21--22 is desirably somewhat greater than the width of the cavity 18, while the overall thickness of the dust guard (over the plates 24) is still greater. In conventional railway car journal boxes, the width of the cavity 18 is approximately of an inch. We therefore prefer to make the pad 21--22 so that, when unstressed, its thickness is about one inch, while a preferred thickness for each of the plates 24 is approximately of an inch. When the dust guard is inserted into the cavity 18 it is compressed axially of the journal to a thickness corresponding to the width of the cavity 18. Because of the thickness of the plates 24, the material between them is compressed to a greater extent than the marginal portions of the pad 21-22; but the pad material possesses sufficient resilience to enable the marginal portions of the pad to bear against the opposed walls of the dust-guard cavity.

A preferred material for each layer of the pad 21 and 22 is a foamed urethane derivative, but the materials for the respective layers 21 and 22 are selected so that such layers have different resistance to compressive forces.

For the layer 21, which is disposed toward the interiorof the journal box, a preferred material is an open-cell polyurethane foam of the polyester type having, when unstressed, a density of about 2.2 lbs. per cubic foot. A preferred material for the rear layer 22 is an open-cell polyurethane foam of the polyether type having, when unstressed, a density of approximately 2.2 lbs. per cubic foot. These two polyurethane foams exhibit substantially different responses to compressive forces. If a pad comprising two equal- thickness layers 21 and 22, respectively of the polyester and polyether types of polyurethane foam, is subjected to a progressively increasing compressive force, the reduction in the thickness of the pad during the initial stage of compression will be represented almost entirely by a reduction in the thickness of the polyether layer 22. At a pressure of 0.5 p.s.i., the polyether layer will be reduced to about one-half its original thickness, while the polyester layer will retain about of its thickness. At 0.8 p.s.i., the polyether layer will be reduced to about 25% of its original thickness and the polyester layer to about 40%. At 1.3 p.s.i., both layers will have a thickness about 20% of the original.

A preferred form of guard, embodying A2 inch layers 21, 22 of the polyurethane foams above described and plates 24 of 7 inch thickness will be subjected to a pressure of about 0.75 p.s.i. in a cavity 18 of 7 8 inch thickness and to a pressure of about 1.0 p.s.i. in a cavity of inch thickness. In the former case, the polyether layer 22 a o-team 3 will represent about 30%, and in the-latter case about 40%, t the total thickness of the compressible pad between the plates 24. When the guard is in place, the marginal portions of the pad beyond the edges of the plates 24 will of course be subjected to less pressure than the center portion of the pad between the plates.

When a dust guard of the materials and dimensions above set forth is compressed and positioned in a dustiguard cavity 18 approximately /4 of an inch in width, the polyether layer 22 will be about one-half as thick and twice as dense as the polyester layer 21. In practice, the width of dust-guard cavities varies between about and about of an inch. Owing to the high compressibilities of the foam layers, our guard accommodates itself to such variations with relatively minor changes in the pressure exerted by the guard on the walls of the cavity. Thus, tests indicate that a pressure of about 0.75 p.s.i. will compress the guard described to an over-all thickness of of an inch, while a pressure of 0.80 p.s.i. is more than enough to compress it to a thickness of of an inch.

We claim as our invention:

1. In combination with a railway-car journal and its associated journal box, said box having a dust-guard cavity in its inner wall and said journal having a collar in the plane of said cavity, a dust-guard located in said cavity, said dust-guard comprising a compressible pad having a central opening snugly receiving said collar, said pad comprising two layers of differentiallycompressible material compressed axially of the journal by confinement of the dust guard within its cavity, the layer of lesser 4. compressibility lying toward the interior of the journal box with respect to the other layer.

2. The combination set forth in claim 1 with the addition of two rigid plates secured to the opposite faces of said pad, the margins of said pad extending outwardly beyond the margins of said plates.

3. The combination set forth in claim 1 with the addition that said two layers, when unstressed, are of approximately equal thickness whereby, when the dust-guard is positioned in its cavity, the layer of lesser compressibility will be substantially thicker than the other layer.

4. The combination set forth in claim 1 with the addition that each of said layers is a sheet of an open-cell elastomer foam.

5. The combination set forth in claim 4 with the addition that said two layers, when unstressed, are of approximately equal thickness.

6. The combination set forth in claim 4 with the addition that one of said layers is of polyurethane foam of the polyester type and the other is of a polyurethane foam of the polyether type.

References Cited in the file of this patent UNITED STATES PATENTS 524,162 Cochrane Aug. 7, 1894 1,939,492 Fisher Dec. 12, 1933 2,152,937 Vigne et a1. Apr. 4, 1939 2,434,228 Sale Jan. 6, 1948 2,793,885 Hoyer May 28, 1957 2,805,182 Hallenbeck Sept. 3, 1957 2.840.396 Hennessy June 24, 1958

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