Motor vehicles – Surface effect vehicles – Dynamic seal or fluid curtain
Patent
1981-03-27
1984-01-31
Mitchell, David M.
Motor vehicles
Surface effect vehicles
Dynamic seal or fluid curtain
91385, 56DIG15, 1042441, 180 79, B62D 506
Patent
active
044284497
DESCRIPTION:
BRIEF SUMMARY
The present application is a simplification of the application of Armin Lang filed Aug. 25, 1978, Ser. No. 936,945, now U.S. Pat. No. 4,304,316 cross reference being made thereto.
STATUS OF THE PRIOR ART
The invention relates to a comparator which is distinguished from the application cross referenced above in the economical use of pumping means which feed the feelers that scan a row or rows of plants for vehicle guidance. Thus, in the previous application certain output signals either in the form of a change in pressure or volume acted upon a tiltable plate or lever which controls valves responsive to movement of the feelers wherein the system required a certain minimum operating power at all times with some reduction in sensitivity as a result. Further, in the previously filed application, the hydraulic lines had to be carefully ventilated, whereas the present construction minimizes any such need.
BRIEF DESCRIPTION OF THE INVENTION
The invention utilizes a comparator which does not require special pumps but effects pressures on each side of a flexible membrane such as a diaphragm or bellows in accordance with flow therepast responsive to the throttling of flow on respective sides of the diaphragm. Such differential throttling of flow and thus a difference in pressure built up on the sides of the diaphragm actuates it to operate valves which control flow to a hydraulic motor for centering vehicle wheels after deflection. Also, by a mechanical connection, the wheels can be brought to neutral or straight ahead position from a deflected position. Such connection acts directly on the membrane to flex it for operating the valves even though the feelers have not contacted plants.
The arrangement operates with considerable sensitivity, since only small movement of the feelers to actuate respective throttles is required. There is a constant flow through a respective chamber on each side of the membrane exhausting through a respective variable throttle operable by the feelers. Accordingly, strict ventilation of the hydraulic lines to the variable throttles is not required, air bubbles being automatically removed by the constant flow. By the use of variable throttles which are simple and inexpensive components instead of special pump generators as in the prior application, a considerable simplification and economy is effected.
A detailed description of the invention now follows in conjunction with the appended drawing, in which:
FIG. 1 is a symbolic layout of an overall system showing a basic form of comparator.
FIG. 2 is a longitudinal elevation through a comparator in accordance with the construction of the invention.
FIG. 3 is a partial section in elevation taken in a plane at right angles to the section of FIG. 2, and
FIG. 4 is a radial section through IV--IV of FIG. 2.
Referring now to FIG. 1, the guide means 1 illustrated either as a row of plants or as a parallel row of plants with certain irregularities as shown, will be understood to be scanned by feelers and represent, for example, rows of growing corn. The broken lines 3 represent guide components of an agricultural vehicle such as a harvester. The vehicle has two feelers, 5a and 5b, which jointly scan the center row for purposes of illustration in this instance. A vehicle wheel 7 is shown which can be steered by a hydraulic motor 9 operative through a control valve 11, such a valve being shown in FIG. 5 of U.S. Pat. No. 4,219,093. The housing 13 illustrates a basic comparator for purposes of illustration.
Control valve 11 is pressure fed by fluid drawn from a tank 15 and passing through a high pressure pump 17, being connected to the opposite pressure chambers of the hydraulic motor 9 via respective lines or conduits 19a and 19b and valve 11 is connected by conduit 20 with tank 15. Fluid flow is in the order of magnitude of 0.5 l/m through the control valve 11 and thence through feed lines 22a and 22b to the comparator 24.
It can be noted at this time that basically the comparator is extremely simple and only a diaphragm 26 is utilized in place of
REFERENCES:
patent: 3693504 (1972-09-01), Gilbert
patent: 3708029 (1973-01-01), Sedgfield et al.
patent: 4219093 (1980-08-01), Lang
patent: 4304316 (1981-12-01), Lang
patent: 4367802 (1983-01-01), Stiff
McGiehan Donn
Mitchell David M.
Zahnradfabrik Friedrichshafen AG.
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