Fluid handling – Systems – With preselecting means for plural valve actuator
Reexamination Certificate
2001-03-28
2003-08-05
Michalsky, Gerald A. (Department: 3753)
Fluid handling
Systems
With preselecting means for plural valve actuator
C137S636200
Reexamination Certificate
active
06601611
ABSTRACT:
FIELD AND BACKGROUND OF THE INVENTION
The invention is based on a hand-actuated control device which is used in particular for the hydraulic actuation of hydraulic valves.
Such a hand-actuated control device is known for example from DE 27 51 946 C2. The control device has a control lever which is mounted cardanically on a device housing by two shafts or shaft stubs, the axes of which form an axial plane and intersect at a swivel point, and is consequently able to be swiveled from a neutral position to all sides about the swivel point. In the case of the known device there are, as control signal generators, four directly controlled pressure-reducing valves, which are arranged at angular intervals of 90 degrees about a lever axis which is perpendicular to the axial plane and passes through the swivel point. Each pressure-reducing valve has an associated tappet, which is guided in the device housing movably parallel to the lever axis, protrudes from the device housing and can be pressed down against the force of a restoring spring and of a control spring of the respective pressure-reducing valve by a plate-like actuating element securely connected to the control lever. The restoring springs acting on the tappet ensure that the control lever in each case assumes a neutral position when it is not being externally actuated and no engagement in a swiveled state is provided for it.
If in the case of the known control device the control lever is swiveled in a plane which is determined by the axes of two diametrically opposed pressure-reducing valves, one of four pressure-reducing valves, that is to say a control signal generator, is actuated. By swiveling the control lever in another plane, it is possible to actuate two pressure-reducing valves simultaneously, the degree of actuation of one pressure-reducing valve in comparison with the degree of actuation of the other pressure-reducing valve being dependent on the position of the swivel plane.
With the known control device, which is customarily used in mobile machines, normally two directional control valve spindles are actuated. For the actuation of further directional control valves, further control devices are necessary. To avoid the expenditure for such further control devices and so as not to take up additional space, it has already been proposed to feed the hydraulic control signals of two pressure-reducing valves of a hydraulic control device which are assigned to the same directional control valve via electromagnetically actuable switching valves to a first or a second directional control valve, allowance having been made for the fact that only some hydraulic consumers of a mobile machine are used simultaneously, while others are always used at different times.
In the case of such pilot control, known from DE 196 30 798 A1, the control device has in addition to four pressure-reducing valves an electric switch, by the actuation which the electromagnets of the switching valves are excited and the switching valves are switched over. It appears to be disadvantageous here that electrical energy has to be additionally supplied to a hydraulic control device which already has a hydraulic pump connection and a hydraulic tank connection. In addition, the actuation of an electric switch requires letting go of the control lever or, if the electric switch is integrated into the control lever, at least altering the way in which it is being gripped. If there is a malfunction of the electric switch, hazardous situations may arise, because valves other than the ones desired are actuated.
SUMMARY OF THE INVENTION
The invention is based on the object of further developing a hand-actuated control device such that a large number of hydraulic valves can be reliably actuated with it, without excessively increasing expenditure.
This object is achieved in the case of a hand-actuated control device according to the invention by this control device being additionally provided with the features disclosed. Accordingly, between two first control signal generators there is arranged a further control signal generator. The control lever can be turned together with the actuating element about the lever axis from a first turning position into a second turning position and vice versa, the first control signal generators being able to be actuated by the actuating element in the first turning position. A recess in the actuating element lies over the further control signal generator when the control lever is in the first turning position, so that said further control signal generator cannot be actuated in the first turning position. By turning the control lever together with the actuating element into the second turning position, a region of the actuating element is moved over the further control signal generator, so that its actuation is possible.
Advantageous refinements of a hand-actuated control device according to the invention can be taken from the subclaims.
In principle, it is conceivable to form the actuating element and arrange the further control signal generator such that, in the second turning position of the control lever, when the further control signal generator is actuated the two first control signal generators are simultaneously also actuated, if the hydraulic consumers are of a type requiring such actuation. If, however, in the second turning position of the control lever, it is to be possible for a control signal generated by the further control signal generator to be emitted simultaneously with a control signal of only one of the first control signal generators, or to be emitted entirely on its own, this is achieved by a form of construction.
The invention can be used with preference in the case of a hand-actuated control device which has four first control signal generators at respective angular intervals of 90 degrees about the lever axis. The activation of a further directional control valve spindle in two directions is possible by being respectively arranged centrally between two first control signal generators two further control signal generators which are diametrically opposite each other in relation to the lever axis, and by the actuating element being provided with four recesses, which in the second turning position are located in the region of the first control signal generators. Consequently, in the first turning position of the control lever only the first control signal generators can be actuated and in the second turning position of the control lever only the further control signal generators can be actuated. It goes without saying that it is possible to arrange at an offset of 90 degrees with respect to the two further control signal generators a second pair of further control signal generators.
The control lever is formed such that it is not rotationally symmetrical in relation to the lever axis, so that it is evident from its position whether it is assuming the first turning position or the second turning position.
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Patent Abstracts of Japan vol. 016, No 165 (M-1238) Apr. 21, 1992 & JP 04 012991 A (Omote Tekkosho:KK) Jan. 17, 1992.
Bosch Rexroth AG
Farber Martin A.
Michalsky Gerald A.
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