1. A wrist pin for operably attaching a small end of a connecting rod to axially aligned pin bores of a piston, comprising:
a cylindrical body having a through bore, said through bore having a first diameter and a second diameter, said first diameter being less than said second diameter; and
wherein said cylindrical body has opposite end portions spaced axially from one another by a central portion, said first diameter being defined in one of said central portion or said opposite end portions and said second diameter being defined in the other of said central portion or said opposite end portions, said first diameter transitioning to said second diameter generally between the small end of the connecting rod and the pin bores of the piston.
2. The wrist pin of claim 1 wherein said first diameter is defined in said opposite end portions and said second diameter is defined in said central portion.
3. The wrist pin of claim 2 wherein said wrist pin is a monolithic piece of material.
4. The wrist pin of claim 1 wherein said first diameter is defined in said central portion and said second diameter is defined in said opposite end portions.
5. The wrist pin of claim 4 wherein said wrist pin is a monolithic piece of material.
6. The wrist pin of claim 1 wherein said first diameter is substantially different from said second diameter.
7. The wrist pin of claim 6 wherein said first diameter and said second diameter are spaced axially from one another by a sudden change in diameter.
8. The wrist pin of claim 1 wherein the first diameter is about 30-60 percent smaller than said second diameter.
9. A piston assembly, comprising:
a piston crown with pin bosses depending therefrom, said pin bosses having axially aligned pin bores;
a crank shaft having a small end with a bore; and
a wrist pin having a cylindrical body with a through bore, said through bore having a first diameter arranged for receipt in one of said crank shaft bore or said pin bores and a second diameter arranged for receipt in the other of said crank shaft bore or said pin bores, said first diameter being less than said second diameter, said first diameter transitioning to said second diameter generally between the small end of the connecting rod and the pin bores of the piston.
10. The piston assembly of claim 9 wherein said first diameter is arranged for receipt in said crank shaft bore and said second diameter is arranged for receipt in said pin bores.
11. The piston assembly of claim 10 wherein said wrist pin is a monolithic piece of material.
12. The piston assembly of claim 10 further comprising a bushing disposed in said crank shaft bore and wherein said pin bores are bushingless.
13. The piston assembly of claim 9 wherein said first diameter is arranged for receipt in said pin bores and said second diameter is arranged for receipt in said crank shaft bores.
14. The piston assembly of claim 13 wherein said wrist pin is a monolithic piece of material.
15. The piston assembly of claim 13 further comprising a bushing disposed in each of said pin bores and wherein said crank shaft bore is bushingless.
16. The piston assembly of claim 9 wherein said first diameter is substantially different from said second diameter.
17. The piston assembly of claim 16 wherein said first diameter and said second diameter are spaced axially from one another by a sudden change in diameter.
18. The wrist pin of claim 9 wherein the first diameter is about 30-60 percent smaller than said second diameter.
19. A method of controlling the rotation of a wrist pin within pin bores of a piston and a wrist pin bore of a small end of a connecting rod by providing controlled expansion of the wrist pin in use, comprising:
providing a cylindrical body having opposite end portions spaced axially from one another by a central portion;
forming a through bore in said body having a first diameter defined in one of said central portion or said opposite end portions and a second diameter defined in the other of said central portion or said opposite end portions, with said first diameter being less than said second diameter; and
forming a pair of transitions between said first diameter and said second diameter so that the transitions are located generally between the small end of the connecting rod and the pin bores of the piston.
20. The method of claim 19 including forming the first diameter so that it is about 30-60 percent smaller than said second diameter.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A structural system for a protective relay used in an electric power system, the relay being responsive to power signals from an electric power line, comprising:
a main circuit board containing a processor for processing digital input signals thereto to carry out protection functions for the relay;
at least one input signal board separate from the main board responsive to analog input signals from the power system, the input signal board having components thereon which require calibration to produce accurate output signals, wherein the input board also has stored thereon calibration information necessary for said accurate output signals, wherein noncalibrated output signals from the input signal board are, following analog-to-digital conversion, communicated to said processor, along with the calibration information stored on the input signal board, for processing, wherein a change of the input signal board does not require recalibration of the entire relay.
2. A system of claim 1, wherein the components on the input signal board requiring calibration include at least one of the following: at least one current transformer, low-pass filters associated therewith, at least one potential transformer and low-pass filters associated therewith.
3. A system of claim 1, wherein the components on the input signal board include current transformers for all three power signal phases, low-pass filters associated therewith, potential transformers for all three phases and low-pass filters associated therewith.
4. A system of claim 3, wherein all of said components are on one input signal board.
5. A system of claim 4, wherein the input signal board also includes an AD converter responsive to the output of the low-pass filters.
6. A system of claim 1, wherein the calibration is carried out for both magnitude and phase errors.
7. A system of claim 3, wherein the current transformers and their associated low-pass filters are on a first input signal board and wherein the voltage transformers and their associated low-pass filters are on a second input board.
8. An input signal board for use in a protective relay used in an electric power system, the relay being responsive to power signals from an electric power line and including a main circuit board which includes a processor for processing digital input signals thereto to carry out protection functions for the relay, the input signal board comprising:
an input signal board having at least one of the following thereon: (a) current transformers for all three phases of the power signal from the power line and a low-pass filter for each current transformer and (b) potential transformers for all three phases of the power signal from the power line and a low-pass filter for each potential transformer, wherein the current transformers and the potential transformers require calibration to produce accurate output signals, wherein the input signal board has stored thereon calibration information necessary for said accurate output signals, wherein noncalibrated output signals from the input signal board are, following analog-to-digital conversion, communicated to said processor, along with the calibration information stored on the input signal board, for processing, wherein the input signal board can be changed in the relay without recalibration of the entire relay.
9. A input signal board of claim 8, wherein the current transformers and their low-pass filters and the potential transformers and their low-pass filters are all on said input signal board.