1. A tractor comprising a transmission casing, a traveling-system power transmission mechanism provided in the transmission casing and interposed between an engine and an axle, a PTO-system power transmission mechanism provided in the transmission casing and interposed between the engine and a PTO shaft, and a changeover mechanism provided in the transmission casing and interposed between both power transmission mechanisms, wherein
when the power transmission of the PTO-system power transmission mechanism is interrupted at a middle portion thereof by the changeover mechanism the changeover mechanism is configured so as to be capable of performing a changeover manipulation to connect a downstream side portion of the PTO-system power transmission mechanism and a downstream side portion of the traveling-system power transmission mechanism,
the changeover mechanism is comprised of a traveling-system power transmission gear which is mounted on a traveling-system power transmission shaft which constitutes a portion of the traveling-system power transmission mechanism, a PTO-system power transmission gear which is mounted on an upstream-side PTO-system power transmission shaft which constitutes a portion of the PTO-system power transmission mechanism, and a shift gear body which is arranged coaxially with the upstream-side PTO-system power transmission shaft and is mounted on a downstream-side PTO-system power transmission shaft which constitutes a portion of the PTO-system power transmission mechanism, and
the shift gear body is formed by mounting a slide member on the downstream-side PTO-system power transmission shaft in an axially slidable manner and by forming a PTO-system side shift gear which is meshed with the PTO-system power transmission gear and a traveling-system side shift gear which is meshed with the traveling-system power transmission gear on the slide member thereby, with the sliding of the slide member, enabling a manipulation to selectively change over the meshing between the PTO-system power transmission gear and the PTO-system side shift gear and the meshing between the traveling-system power transmission gear and the traveling-system-side shift gear.
2. A tractor according to claim 1, wherein a PTO transmission part which comprises the PTO shaft is detachably mounted on the transmission casing and an input shaft which is provided to the PTO transmission part is detachably connected to a downstream-side end portion of the PTO-system power transmission mechanism.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A sample preparation apparatus for flash chromatography, comprising:
a source of microwave radiation for applying microwave energy;
a microwave cavity in wave communication with said source;
a microwave transparent vessel in said cavity holding chromatography media; and
a gas pump in gas communication with said vessel in said cavity for moving gases through said vessel during the application of microwaves to the vessel and chromatography media to facilitate evaporation of solvent from said chromatography media.
2. The apparatus according to claim 1, wherein said microwave source is selected from the group consisting of magnetrons, klystrons, and solid state devices.
3. The apparatus according to claim 1 further comprising a microprocessor for controlling said microwave source.
4. The apparatus according to claim 1, comprising a waveguide between said source and said cavity.
5. The apparatus according to claim 1, wherein said vessel comprises a chamber portion and a top portion.
6. The apparatus according to claim 1, wherein said microwave transparent vessel is selected from the group consisting of glass, polymers and quartz.
7. The apparatus according to claim 5, comprising a gas inlet about said top portion of said vessel for allowing make-up gas into said vessel.
8. The apparatus according to claim 7, wherein said gas inlet comprises tubing projecting into said vessel.
9. The apparatus according to claim 1, comprising a gas outlet about said vessel for allowing solvent to evacuate said vessel.
10. The apparatus according to claim 9, wherein said gas outlet communicates with said gas pump.
11. The apparatus according to claim 1, comprising chemical resistant tubing between said vessel and said gas pump.
12. The apparatus according to claim 3 wherein said microprocessor controls said microwave source and said gas pump.
13. The apparatus according to claim 7, wherein said gas inlet is in physical communication with said gas pump; and
said gas pump maintains pressure in said vessel to facilitate the evaporation of the solvent from the chromatography media.
14. The apparatus according to claim 1, wherein said gas pump comprises a vacuum pump.
15. A microwave-assisted chromatography sample preparation instrument, comprising:
a microwave source;
means for controlling the application of microwave energy from said microwave source;
a microwave transparent vessel in wave communication with said microwave source for evaporating solvent from a solvent-containing composition;
a gas inlet tube about said vessel for allowing make-up gas into said vessel;
a gas exit tube about said vessel for allowing solvent to evacuate said vessel; and
a gas pump in physical communication with said vessel for creating a gas flow through said vessel to evaporate solvent from the solvent-containing composition in the vessel and from the vessel during and between applications of microwave energy.
16. The instrument according to claim 15, wherein said microwave source is selected from the group consisting of magnetrons, klystrons, and solid state devices.
17. The instrument according to claim 15, wherein means for controlling the application of microwave energy comprises a microprocessor in signal communication with said source for controlling the application of microwave energy from said microwave source to said sample.
18. The instrument according to claim 17, comprising means for pulsing the microwave energy to avoid overheating the sample.
19. The instrument according to claim 15, comprising a waveguide between said source and said vessel.
20. The instrument according to claim 15 wherein said microwave transparent vessel is selected from the group consisting of glass, polymers, and quartz.
21. The instrument according to claim 15, wherein said gas outlet communicates with said gas pump using chemical resistant tubing.
22. The instrument according to claim 15 wherein said microprocessor simultaneously controls said microwave source and said gas pump.
23. The instrument according to claim 15, further comprising a temperature sensor for measuring the temperature of the sample.
24. The instrument according to claim 23, wherein said temperature sensor is selected from the group consisting of infrared detectors, ultraviolet detectors, and fiber optic sensors.
25. The instrument according to claim 23, comprising a temperature sensor in signal communication with a computer microprocessor.
26. The instrument according to claim 25, wherein said microprocessor is in signal communication with said source and with said temperature sensor for thereby moderating the application of microwaves from the source based upon the monitored temperature.