Claims
- 1. An improved fabricated resistor grid having a frame including a pair of oppositely positioned conducting members and a zigzag resistor comprising flat individual strips of resistance material positioned opposite each other, each strip having an offset portion at each end, said offset portions being parallel to each other and extending in opposite directions, each offset portion being joined to the opposite direction offset portion of the adjoining strip so as to form a current path between the said conducting members,
- the improvement comprising
- a short supporting member of conductive material of a gauge at least equal to that of said strip forming a sandwich between each of said joined offset portions and projecting outwardly therefrom, parallel to said offset portions, and a block of insulating material carried by said conductive members having recesses in its inner surface adapted to mate with said outwardly projecting supporting members.
- 2. The fabricated resistor grid of claim 1 in which said sandwich is held together by a resistance weld between said short supporting member and said adjoining offset portions.
- 3. The fabricated resistor of claim 1 in which said sandwich is held together by a nut and bolt in compression; said bold extending through said short supporting member and said adjoining offset portions.
- 4. The fabricated resistor grid of claim 1 in which said supporting strip of conductive material extends inwardly between said parallel strips.
- 5. The fabricated resistor grid of claim 1 in which the outwardly projecting end of said supporting strip is divided into parallel segments.
- 6. The fabricated resistor grid of claim 1 in which the outwardly projecting end of said supporting strip terminates in outwardly extending solid cylindrical studs.
- 7. The fabricated resistor grid of claim 1 in which the outwardly projecting end of said supporting strip terminates in outwardly extending hollow cylindrical studs.
- 8. The fabricated resistor grid of claim 1 in which said block of insulating material fits into an opening in said structural member, said opening having a greater length than said block with spaced projections on each side of said block that overlap inwardly extending spaced projections from said structural member in said opening when said block is at one end of said opening and do not overlap said inwardly extending projections when said block is at the other end of said opening.
- 9. The fabricated resistor grid of claim 1 in which said joined offset portion is formed to include cylindrical passages therethrough and said cylindrical passages are filled by solid cylindrical elements which project beyond said offset portions so as to mate with recesses in said block of insulating material.
- 10. The fabricated resistor of claim 9 in which said solid cylindrical elements project inwardly beyond said offset portions between said parallel strips.
- 11. The fabricated resistor grid of claim 9 in which said solid cylindrical elements are the ends of a U-shaped cylindrical bar, the cross piece of which bar is positioned within said offset portion.
- 12. The fabricated resistor grid of claim 1 in which said strips of resistance material are embossed longitudinally so as to stiffen them.
- 13. The fabricated resistor grid of claim 1 in which said strips of resistance material are lanced or severed longitudinally between said offset portions.
- 14. The fabricated resistor grid of claim 1 in which the frame is a rectangular frame having a top member and a bottom member each connected to said oppositely positioned conducting members.
- 15. The fabricated resistor grid of claim 1 in which the frame is an annular frame.
BACKGROUND OF THE INVENTION
This application is a continuation-in-part of our application Ser. No. 465,323, filed Jan. 16, 1990, now U.S. Pat. No. 5,049,8 issued on Sep. 17,1991
Our invention relates to resistors used for dynamic braking in diesel-electric locomotives. It is more particularly concerned with such a fabricated resistor grid assembly having a novel heat dissipating construction which makes possible the use of organic or other inexpensive insulation between the resistor element and the frame of the grid.
The braking of diesel electric locomotives conventionally involves the shunting of the motor terminals with a resistor or bank of resistors. When that is done, the motors, driven by the moving locomotives, act as generators and the current they generate passes through the shunt resistors. The resistor converts the current into heat which in turn must be dissipated. Conventionally the resistor comprises a folded or zigzag strip or strips of resistance material mounted in a metal frame. That strip may be a unitary fan-folded strip, as is shown in Kirilloff et al. 4,109,526 and 4,651,124, or a fabricated zigzag strip such as is shown in Harkness 4,651,125 and 4,654,627.
Our invention utilizes a zigzag resistor element mounted in a rectangular or annular frame, the element being made up of individual strips of resistance material, each strip having an offset at each end in opposite directions. Each offset end portion is joined to the end of the adjoining strip offset in the opposite direction through a third strip element or tab which projects between the offset ends and at its outside end is configured to mate with a hole or cavity in a body of insulating material carried by the side element of the frame. This third element may be thicker than the resistor strip and may project inwardly between the undivided strips so as to form a heat sink.
US Referenced Citations (3)
| Number |
Name |
Date |
Kind |
| 4051452 |
Luy |
Sep 1977 |
|
| 5045831 |
Kirilloff et al. |
Sep 1991 |
|
| 5049851 |
Kirilloff et al. |
Sep 1991 |
|
Continuation in Parts (1)
|
Number |
Date |
Country |
| Parent |
465323 |
Jan 1990 |
|
Patent Grant
5159310
