Tool for Positioning Railway Track Components and Method of Manufacture

The invention concerns devices used to position railway tracks and ties or sleepers, and methods of making such devices. More particularly, the invention concerns the spade-shaped tools used in railway building equipment to move tracks and ties to desired positions, and methods of making such tools.

When adjusting railway tracks, ties and similar devices to the proper position for use, very sophisticated machines often are used. These machines typically include hydraulically activated, rather simple spade-shaped tools which are used to move the tracks to the correct position. Railway track ties, or sleepers, rest on and in a bed of gravel, macadam or other ballast material. The spade-shaped tools are pressed with great force downward through this bed, then under and in toward the sleepers. Due to the great amount of wear to which the tools are subjected by the bed material, they will usually be worn out within a few days. The portion of the tools which actually wears out is the blade or working surface, while the integral support shaft experiences much less wear. In spite of this, the prior art practice has been to replace the entire tool since the tool is manufactured in one piece.

An object of the present invention is to provide an improved tool of the type just discussed in which it is possible to replace only those portions of the tool which are actually worn.

A further object of the invention is to provide a method of manufacturing the replaceable blade for such a tool.

These objects of the invention are given only by way of example. Thus, other desirable objectives and advantages of the invention may occur or become apparent to those skilled in the art. Nonetheless, the scope of the invention is to be limited only by the appended claims.

In a tool according to the invention, the shaft as well as the blade will become worn; however, wear on the shaft has been estimated to be approximately one tenth that of the blade. Thus, one shaft could last as long as ten blades before it has become worn to such a degree as to require replacement.

In accordance with the invention, an improved tool for incorporation in machines used to position railway tracks and ties comprises a support shaft and a blade member which is mounted by force-fit on the shaft. The support shaft has a first axis, an upper end adapted to be gripped by such machines and a lower end. The lower end is tapered upwardly and outwardly from the first axis and has a transverse cross section which tapers inwardly from the front side of the lower end toward the back side of the lower end. The blade member has a second axis, a front side, a back side and a pair flanges extending from the back side to define an upwardly extending and opening slot in which the lower end of the support shaft is received with the front side of the shaft facing the back side of the blade member. The slot in the blade member is tapered upwardly and outwardly from the second axis and has a transverse cross section which tapers inwardly toward the center of the slot, as measured from the back side of the blade member toward the outer ends of the flanges. As a result, when the lower end of the support shaft is forced into the slot on the back of the blade member, the blade member is removeably secured to the support shaft by a force fit, thereby permitting replacement of a worn blade member and reuse of the support shaft. Preferably, the flanges on the blade member are formed integrally with the blade member during casting or forging operations.

In accordance with the method of the invention for manufacturing the tool of this type, a support shaft of the type previously mentioned is formed. An intermediate form of the blade member is then formed which has a second axis, a front side, a back side and a pair of integral flanges extending from the back side to define an upwardly extending and opening slot for receiving the lower end of the support shaft, the slot being tapered upwardly and outwardly from the second axis of the blade member. Thereafter, the blade member is deformed to cause the outer end of the flanges to move toward the second axis of the blade member so that the slot thereafter has a transverse cross section which tapers inwardly toward the center of the slot, as measured from the back side of the blade member toward the outer ends of the flanges. Depending on the method used to manufacture the blade member, the initial forming step may cause the blade member to be flat or to bow toward the flanges. In the first instance, the deforming of the blade member simply comprises bending of the flanges toward the center of the slot to cause a taper to form in the transverse cross section of the slot. In the latter instance, the blade member is deformed by essentially flattening it to cause a taper to form in the transverse cross section of the slot.

FIG. 1 shows a side view of a support shaft according to the invention.

FIG. 2 shows a back view of a support shaft according to the invention, as seen from the left in FIG. 1.

FIGS. 3 and 4 show sectional views taken along lines 3--3 and 4--4 in FIGS. 1 and 2.

FIG. 5 shows a side view of a blade member according to the invention.

FIG. 6 shows a rear view of a blade member according to the invention.

FIG. 7 shows a top view of a blade member according to the invention.

FIG. 8 shows a top view of an intermediate stage in the manufacture of the blade member in which the body of the blade member is bowed convexly toward the flanges on its back side and the transverse cross section of the slot between the flanges is not tapered.

FIG. 9 shows a top view of an intermediate stage in the manufacture of the blade member in which the body of the blade member is essentially flat and the transverse cross section between the flanges is not tapered.

FIG. 10 shows an assembled tool according to the present invention.

The following is a detailed description of the invention, reference being made to the drawing in which like-reference numerals identify like-elements of structure in each of the several Figures.

FIGS. 1-4 show various views of a support shaft 10 according to the invention which may be made by forging, casting or machining from a suitable material such as steel. A longitudinal axis 12 extends through shaft 10 and the upper end 14 of the shaft is configured as necessary to be gripped by the machinery for positioning railway track and ties. The lower end 16 of shaft 10 is tapered upwardly and outwardly at an angle .alpha. measured between the side edges 16a, 16b of lower end 16.

As shown in FIGS. 3 and 4, the transverse cross sections 18, 20 taken at about the upper and lower ends of lower end 16 are essentially trapezoidal in configuration except for a small rectangular portion 21 at their bases. The edges of portion 21 preferably are chamfered. Cross sections 18, 20 taper inwardly from one side 22, the front side of the shaft in use, to the other side 24, the back side of the shaft in use, at an angle .gamma. as shown in FIGS. 3 and 4. The very bottom of shaft 10 has a chisel-like surface 25 which extends from back side 24 to front side 22.

As shown in FIGS. 5-7, the blade member 26 according to the invention includes a central vertical axis 28, a front side 30 and back side 32. The overall shape of the front and back sides is essentially rectangular; however, as shown in FIG. 5, the vertical cross section of the blade member 26 is essentially trapezoidal and tapered downwardly and toward front side 30 from the top edge of the blade. On the back side 32, a pair of flanges 34, 36 are provided which preferably are formed integrally with the blade during manufacture. The flanges are essentially rectangular in shape, although their lower edges 34a, 36a slope downwardly toward front side 30 and the lower edge 37 of the blade; so that, the lower edge 37 is of a relatively uniform thickness as best seen in FIG. 5.

Between flanges 34, 36, an upwardly and outwardly tapered slot 38 is defined which extends upwardly from the lower ends 38a of the flanges 34, 36 and outwardly at an angle .beta. to the upper ends 38b of the flanges. Slot 38 preferably is symmetrical about axis 28. As shown in FIG. 7, slot 38 includes a transverse axis 40 and the transverse cross section of the slot, at any given height along the slot, tapers inwardly toward axis 40 from the base ends 42, 44 to the outer ends 46, 48 of flanges 34, 36. Thus, as shown in FIG. 7, the transverse cross section of slot 38 tapers at an angle .delta. symmetrically about axis 40. The interior angles of slot 38 at base ends 42, 44 are equal.

As previously indicated, the lower end 16 of shaft 10 is tapered. Preferably, this taper is rather gradual along the widest part of lower end 16 so that the edges 16a, 16b, as extended, form an angle .alpha. which is less than or equal to 10 degrees. The angles .gamma. between the non-parallel sides of the cross sections 18, 20 shown in FIGS. 3 and 4 preferably are in the range 30 to 50 degrees and equal in magnitude. On blade member 26, the upwardly extending edges of flanges 34, 36 form an angle .beta. of less than or equal to 10 degrees, as shown in FIG. 6; and the horizontally extending edges of the flanges form an angle .delta. of 30 to 50 degrees, as shown in FIG. 7. Angles .gamma. and .delta. preferably are in the range of 30 to 50 degrees; angle .gamma. is less than or equal to angle .delta. and angle .gamma. and angle .delta. differ from each other by no more than two degrees, preferably one degree.

FIGS. 8 and 9 show intermediate forms of blade member 26 during manufacture. Depending upon the precise mode of formation used for the blade member, it may assume the form shown in FIG. 8 in which it bows convexly toward flanges 34, 36 or the form shown in FIG. 9 in which the blade is essentially flat. In either case, at any given height along the slot the transverse cross section of slot 38 is essentially rectangular, rather than inwardly tapered in the manner previously described. To achieve the necessary transverse taper in the situation shown in FIG. 8, blade member 26 is deformed as a whole, using any convenient technique, to the essentially flat configuration shown in FIG. 7. Due to such deformation, flanges 34, 36 swing inwardly to define the tapered transverse cross section. Further inward deforming of the flanges may be necessary in some instances to achieve the desired cross section. Should the blade bow concavely toward the flanges, not illustrated, straightening the blade may require subsequent local deforming of the blades inward to the desired transverse cross section. In the situation shown in FIG. 9, the flanges 34, 36 are themselves locally deformed inwardly toward axis 40 to achieve the desired taper.

To assemble the tool according to the invention, shaft 10 is inserted into slot 38 so that axes 12 and 28 coincide, as shown in FIG. 10. Means such as a heavy hammer are used to force blade member 26 into engagement with shaft 10. Or the hydraulic drive of the associated machinery may be used to seat the blade. A worn blade is simply knocked off in the opposite direction.