US2894078A

US2894078A - Contact shoe for conductor rail

Info

Publication number: US2894078A
Application number: US585454A
Authority: US
Inventors: Jr Edison A Harkins
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-05-17
Filing date: 1956-05-17
Publication date: 1959-07-07
Anticipated expiration: 1976-07-07

Description

July 7, 1959 E. A. HARKINS, JR

CONTACT SHOE FOR CONDUCTOR RAIL Filed May 17. 1956 can r I .I

25 6 mm am f j V INVENTOR a 50/50 A. l/AQk/A/S J2.

298mm 44k All; ATTORNEJ 2,894,078 Patented July 7, 1959 CONTACT SHOE FOR CONDUCTOR RAIL Edison A. Harkins, In, Bordentown, NJ.

Application May 17, 1956, Serial No. 585,454

" Claims. (Cl. 191-45) This invention relates to a contact shoe for collecting current from the conductor rails which transmit power to crane hoists and the like. More particularly, it is concerned with the problem of eliminating failure or loss of power as the result of dirt accumulating on the conductor rail. In this respect, the invention contemplates improvements in conductor rail contact shoes which are effective in the removal of dirt from the conductor rails and which provide a self-cleaning action for clearing the shoe of dirt removed from the rail.

Eflicient transfer of power from a conductor rail is dependent on its having good electrical contact with the current collecting shoe or trolley wheel on a crane or other trolley carriage. Collections of dirt and grease on the conductor rail can and frequently do interfere with the electrical contact between the rail and current collecting shoe and thus cause a loss or failure of power. In such case, the shoe in moving over the rail gathers the dirt in front of its direction of movement and its continued movement may result in the dirt being rolled between the shoe and rail with a wedging action. In this manner, the dirt may be effective to raise the shoe relative to the rail and thereby provide a poor contact if not an open circuit and consequent failure of power. The elimination of power losses and failures of this character is one of the principal objects of this invention. Another object of the invention is to provide improvements in contact shoes which are operative to remove dirt and grease from a conductor rail while maintaining an effective electrical contact therewith.

The above and related objects of the invention are accomplished by the provision of a contact shoe in which a plurality of current collecting conductor bars have simultaneous sliding contact with the rail. The shoe includes a common supporting structure for moving the conductor bars over the rail and on which the conductor bars are mounted for independent movement relative to each other and relative to such supporting structure. This provision for independent movement in a manner to be described enables one or more of the conductor bars to move out of electrical contact with the rail without interrupting the current collecting elfectiveness of the shoe. Incidental to this feature of the invention, each of the conductor bars has an electrical connection through a shunt circuit to a power transmitting cable which is independent of a circuit to such cable through the metal parts of the shoe.

Further details and advantages of the invention will be come apparent from the following description. In the drawings, there is shown a preferred embodiment of the invention. In this showing:

Figure l is a plan view in which a pair of contact shoes constructed in accordance with the principles of this invention are shown in their operative positions with respect to a pair of vertically spaced conductor rails;

Figure 2 is a front elevational view looking in the direction designated by the line IIII in Figure 1; and

Figure 3 is an enlarged detail and fragmentary sectional view of a portion of one of the shoes shown in Figure 1.

As indicated above, the contact shoe of this invention is particularly suitable for the purpose of collecting current from conductor rails which extend along the trackway for a trolley carriage such as one supporting an overhead crane hoist. The power collected by the shoe is of course transmitted as in conventional practice to the drive for the carriage and the crane or other mechanism carried thereby. In the drawings, horizontal conductor rails are designated by the numeral 1 and it will be understood that such rails extend along the trackway (not shown) for a crane or other carriage (not shown). The numeral 2 designates a wood standard which is secured to the carriage (not shown) for movement therewith and which mounts a pair of contact shoes 3a and 3b respectively constructed in accordance with the principles of this invention. As in conventional practice, the contact shoes 3a and 3b collect current from the conductor rails 1 and form part of the energizing circuit for the drive mechanism on the carriage to which the standard 2 is secured. As best shown in Figure 2, the standard 2 mounts upper and lower contact shoes 3a and 3b which respectively collect current from vertically spaced rails 1a and 1b. The structures of the shoes 3a and 3b are identical and the ensuing description applies to both.

Each of the shoes 3a and 3b comprises a supporting bracket 4 having arms 5 which are connected by a horizontal pivot pin 30 to the standard 2 for pivotal movement about an axis parallel to the conductor rail 1. The bracket 4 may be conveniently constructed by bending a steel strap to the U-shaped configuration shown in the drawings. A brace bar 6 has its ends welded to and braces the arms 5 against movement relative to each other. The bar 6, bracket sides 7 and bracket end 8 define an opening 9 which is centered over the conductor rail 1 when the bracket 4 is in its operative position as shown in the drawings. By reason of its pivotal support, each bracket 4 has a gravitational bias for pivotal movement in a counterclockwise direction as viewed in Figure 2 to its operative position. The bracket sides 7 are angularly inclined transversely of the length of the conductor rail 1 for a purpose to be described.

A current collecting assembly of a plurality of parallel contact bars or plates 11 respectively extending transversely of the conductor rail 1 is arranged centrally of the bracket opening 9. As best shown in Figure 2, the conductor bars or plates 11 have a rectangular shape and a vertical dimension greater than the bracket sides 7 so that a bottom portion 12 projects below the lower edge 13 of the bracket 4 for sliding engagement at its center with a conductor rail 1. The mounting of the conductor bars 11 on the bracket 4 comprises a pair of rods 15 respectively positioned on opposite sides of the rail 1 and which extend through aligned openings 17 and 18 in the bracket sides 7 and in opposite ends of the conductor bars 11. Washers 16 on the rods 15 space the rods 11 relative to each other. As best shown in Figure 3, the diameter of the openings 17 and 18 is greater than the diameter of the mounting rods 15 extending therethrough. By reason of the angular inclination of the axes of the openings 17 and 18 relative to the mounting rod 15, the conductor bars 11 and rods 15 are restrained against movement in a horizontal direction extending lengthwise of the bars 11. However, and since the openings 17 and 18 have a greater vertical dimension than the rod 15, it will be apparent that each of the bars 11 may move vertically, that is, in a direction normal to the plane of the drawing as viewed in Figures 1 and 3, relative to the remaining bars 11 and to the bracket 4 for a purpose to be described. This mounting of the bars 11 provides for their movement both toward and away from the rail 1 in a vertical direction which is transversely of their path of movement over the rail 1.

Current collected by each shoe 3a and 3b is transmitted through a cable 20 to the drive mechanism for the crane carriage. 20 in electrical contact with one of the bracket sides 5 so that current collected by the conductor bars 11 is conducted through the metal parts of the bracket to'the cable 120. To avoid pitting of the supporting rods 15 by current conducted in this manner and to insure an electrical con- A clamp 21 secures one end of the cable" nection between each of the bars 11 and the cable 20, there is provided a shunt circuit which is comprised of a pair of conductor leads 22 and a bridging conductor 23.

The bridging conductor 23 has a soldered connection 24 with each conductor bar 11 at a point centrally of its upper edge. One terminal of each of the leads 22 has a soldered connection 25 to the bridging conductor 23 and its other terminal 'is secured by the clamp 21in electrical contact with the cable 20. In this manner, the current collected by each of the conductor bars 11 may be transmitted directly to. the cable 20 through the bridge conductor leads 23 and 22 without going through the metal bars 11 and bracket 4 provides a gravitational bias for maintainiing the lower edge 12 of each bar 11 in contact with the rail 1. However, the dimensional diiference between the openings 18 and mounting rods 15 in a vertical direction as described above enables each bar 11 to move vertically relative to the others and without imparting movement to the bracket 4 as it moves over elevations on the rail 1. In this manner, upward movement of one of the conductor bars 11 is ineffective to interfere with the electrical contact of the remaining bars with a conductor rail 1. The angular inclination of the bars 11 is of course effective to move dirt laterally from the rail 1. In the event that any dirt or grease on a conductor rail moves under and elevates one of the bars 11 out of electrical contact therewith, an electrical contact will be had through the remaining bars. Alternate bars 11 are preferably fabricated of steel and brass plates; the steel plates providing improved wear resisting prop connecting said conductor straps, and means mounting said bracket on said support.

2. A contact shoe assembly for collecting current from a conductor rail comprising a bracket of conductive material, a pair of spaced parallel rods carried by said bracket, said rods being made of conductive material, a plurality of conductor straps extending transversely of said rods and having openings in the ends thereof through which said rods project to support said straps on said bracket, said openings being larger than said rods in a direction generally normal to the plane through the axes of said rods so that said straps have limited movement relative to each other and to said bracket, a support, and means mounting said bracket on said support.

3. A contact shoe assembly for collecting current from a conductor rail comprising a support, a bracket of conductive material, a pivotal connection between said bracket and said support, a pair of spaced parallel mounting rods carried by said bracket parallel to the axis of "said pivotal connection, a plurality of conductor straps having openings in the ends thereof through which said rods project to support said straps on said bracket, said straps extending transversely of said rods, said openings independently of said bracket and strap mounting rods.

4. A'contact shoe assembly for collecting current from a conductor rail comprising a support, a bracket of conductive material, a pair of spaced parallel mounting rods carried by said bracket, a plurality of conductor straps erties and the brass plates providing improved conductor properties in the shoe.

As shown in Figure l, the bars 11 and bracket sides 7 in the upper and lower shoes 3a and 3b have angular inclinations in reverse directions. and grease removed from a conductor r-ail by the upper shoe will not gravitate onto the lower shoe.

While one embodiment of my invention has been shown and described it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims.

I claim:

1. A contact shoe assembly for collecting current from a conductor rail comprisinga bracket of conductive material, a pair of spaced parallel rods carried by said bracket, a plurality of conductor straps extending transversely of said rods and having openings in the ends thereof through which said rods project to support said straps on said bracket, said openings being larger than said rods in a direction generally normal to the plane through the axes of said rods so that said straps have limited movement relative to cachother and to said bracket, a support, flexible means for conductively inter- In this manner, dirt having openings in the ends thereof through which said rods project to support said straps on said bracket, said straps extending transversely of said rods, said openings being larger than said rods in a direction generally normal to the plane through the axes of said rods so that said straps have limited movement relative to each other and to said bracket, a connection mounting'said bracket on said support for movement in a direction normal to a plane through the axes of said rods, and flexible means for conductively interconnecting said conductor straps.

5. A contact shoe assembly for collecting current from a conductor rail comprising a support, a bracket of conductive material, a pair of spaced parallel mounting rods carried by said bracket, said rods being made of conductive material, a plurality of conductor straps having openings in the ends thereof through which said rods project to support said straps on said bracket, said straps extending transversely of said rods, said openings being larger than said rods in a. direction generally normal to the plane through the axes of said rods so that said straps have limited movement relative to each other and to said bracket, and a connection mounting said bracket on said support for movement in a direction normal to a plane through the axes of said rods.

References Cited in the file of this patent UNITED STATES PATENTS 959,197 Belzner May 24, 1910 2,003,209 De Saint-Martin May 28, 1935 2,582,440 Keaton et al. Jan. 15, 1952 2,699,597 Arms Jan. 18,1955