Pumps – Expansible chamber type – Distributor movement adjustable
Patent
1994-05-24
1996-11-19
Thorpe, Timothy S.
Pumps
Expansible chamber type
Distributor movement adjustable
251106, F04B 3908
Patent
active
055756336
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a hydraulic pumping unit for feeding the hydraulic tilting cylinder(s) of a vehicle having a tilting cab, in which a control valve body is provided, at an end projecting beyond the pumping unit housing, with a handle by means of which the control valve body may be turned between at least two positions operative to tilt the cab from the drive position and to tilt the cab back into the drive position of the vehicle respectively.
2. Discussion of the Prior Art
Such a pumping unit, which is designed for manual control, is disclosed in EP-A-0212008. In this well-known pumping unit, the handle is formed by a pin that is extending radially through the projecting control valve end and enables the application of a moment that is large enough to overcome the friction between the control valve body and the bore.
For such pumping units, it is of importance that they can be protected against unauthorized control to prevent, in particular, the cab from being tilted from the driving position by unauthorized persons.
Various solutions have been proposed for this purpose. It has been known, e.g., to apply a solenoid valve in a supply conduit to the hydraulic tilting cylinder, which valve is normally closed and can be opened only by energization (e.g., through a key) from the cab in order to be able to have the tilting cylinder operate by means of the pumping unit.
It is also known to apply a normally opened solenoid valve in a connecting conduit between the pressure conduit and the return conduit of a hydraulic tilting cylinder. In that case, for tilting the cab from the driving position, the valve has to be closed; this, however, can be effected only through electrical energization from the cab.
Such solutions require electrical wiring between the pumping unit and (the dash-board in) the cab, which involves an additional source of failures.
It is also known to prevent unauthorized persons from carrying out the pumping action by blocking the pumping lever or the control valve by means of a (pad) lock or by applying a lock which prevents the pump lever from being inserted in its connecting hub.
The use of separate locks, however, is awkward, whereas such additional means may easily get lost.
SUMMARY OF THE INVENTION
The present invention aims at providing a simple and handy solution, which avoids the disadvantages of the solutions proposed so far.
In accordance with the invention this aim is achieved, in that the handle comprises an inner part that is fixedly connected with the control valve body, and an outer part which is normally enclosing said inner part in a free rotating manner but is mounted to be coupled with said inner part by means of a key-operated lock cylinder, said outer part forming the proper handle.
It is to be noted that U.S. Pat. No. 4,231,240 discloses a screw cap assembly for an automotive gasoline reservoir, which compromises an inner screw-threaded plug part with a key operable cylinder lock for coupling (uncoupling) said inner part with (from) an outer handle part.
The invention will be hereinafter further explained by way of example with reference to the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an axial section through the control knob of the pumping unit according to the present invention;
FIG. 2 is a cross-section along the line II--II of FIG. 1;
FIG. 3 is a cross-section along the line III--III of FIG. 1;
FIG. 4 is a cross-section along the line IV--IV of FIG. 1; and
FIG. 5 shows a longitudinal section through the end portion of the control valve body that extends beyond the pump housing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to the drawing only that part of the housing 1 of the pumping unit is shown, where the rotatably mounted control valve body 2 extends with an end portion 3 beyond the housing 1. 4 reference numerals designates a dish-shaped element, provided with a neck portion 5, that is clampingly engaged in the outer part of the bore 6. A sealing ring 7 is pro
REFERENCES:
patent: 2594141 (1952-04-01), Feighner
patent: 2700984 (1955-02-01), Gleasman
patent: 4231240 (1980-11-01), Fujita et al.
patent: 5213308 (1993-05-01), Jeromson et al.
patent: 5285997 (1994-02-01), Chang
Boel Gustav H. P.
Sonneborn Lambertus J.
Applied Power Inc.
Korytnyk Peter G.
Thorpe Timothy S.
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