Power plants – Pressure fluid source and motor – Pump means moves motive fluid from one chamber to an...
Reexamination Certificate
1999-08-06
2001-07-10
Look, Edward K. (Department: 3745)
Power plants
Pressure fluid source and motor
Pump means moves motive fluid from one chamber to an...
C060S484000, C296S107010
Reexamination Certificate
active
06256987
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a hydraulic operating apparatus, especially for a vehicle covering, having a reversible pump which, via hydraulic lines, one of which is in all cases provided with an unblockable check valve, is connected with the working chambers of at least one double-acting piston-cylinder arrangement.
2. The Prior Art
AT 396.613 discloses an operating apparatus for vehicle coverings wherein the valve-stem side and piston side working chambers of two piston-cylinder arrangements are controlled from both outlets of a reversible pump in order to extend and pull in the covering. The different volumes are balanced out from the reservoir of the hydraulic medium as controlled via a change-over valve. For achieving an emergency stopping function which, depending on demand, can be provided on one or also on both sides, a check valve is employed in one of the hydraulic line. This check valve is unblocked by the pressure in the system at normal operation.
In addition to the operation of the covering itself, an automatic operation of the covering of the cover and/or of its locking mechanism is increasingly desired. For this purpose, further piston-cylinder arrangements are provided which are either supplied via an additional, separate hydraulic circle or are controlled by the main pump of the system via suitable line, valve and control arrangements and the like. Both variants require a relatively large constructive and control-technical effort and increase both the weight and cost of the device.
Thus the object of the present invention is to provide a hydraulic operating apparatus of the above-mentioned type with which, in a simple manner and with a minimum of constructive and control-technical effort, a flexible supply and control of mutually independently operated piston-cylinder arrangements is possible.
SUMMARY OF THE INVENTION
This problem is solved according to the invention in that additional hydraulic lines branch off from both outlet line of the reversible pump, are placed into the check valves, which additional hydraulic lines lead into a common hydraulic line to at least one additional piston cylinder arrangement. In this manner, a pressurized hydraulic medium for the control of the additional piston-cylinder unit, such as for the movement of the covering cap and/or the locking cylinder present in all cases, is available without the need for additional complete hydraulic circle or costly control valve arrangements, being independent of the direction of rotation of the reversible pump and thus independent of the movement of the first piston-cylinder arrangement such as for the movement of the covering itself.
A very simple construction can be realized for the independently controllable pulling-inward or extending-outward of the additional piston-cylinder unit by also making the additional piston-cylinder arrangement double-acting, by dividing the common hydraulic line into two supply lines to both of the working chambers of the additional piston-cylinder arrangement and by providing a change-over valve in one supply line for leading the corresponding working chamber away into a reservoir or for the supply with hydraulic medium from a supply line. The independent controllability of the at least one additional piston-cylinder arrangement is thus only realizable with one change-over valve.
If, according to a further characteristic of the invention, a check valve is placed into the supply line to the change-over valve, an emergency stopping function can be also guaranteed for the at least one additional piston-cylinder arrangement and the uncontrolled falling-back, for example, of the covering cap or the pulling-inward of the locking cylinder upon failure of the hydraulic system can be prevented.
It can be advantageously provided that a derivative line branches off into the reservoir from the common hydraulic line, in which derivative line a pressure-limiting valve is placed. In so doing, the system pressure can be completely limited and thus a damaging of its parts as well as of the covering and its aid components.
To allow for a manual emergency operation of the additional piston-cylinder arrangement or of the parts normally moved by it, for example, in the course of the opening and/or closing of the covering, a blockable derivative line branches off from the common hydraulic line into the reservoir in which a throttle valve is placed. In a failure of the hydraulic system and, for example, a manual opening of the derivative line, the affected parts, such as those burdened by its weight, can slowly sink back into their resting position against the resistance of the throttle valve.
According to a further characteristic of the invention, into a derivative line, a blockable line empties as preferably coupled with the former, which blockable line originates from the hydraulic line between the reversible pump and the piston-cylinder arrangement, preferably from a position between a check valve present in all cases and the piston-cylinder arrangement. Thus, in the case of the necessity of an emergency manual operation, it is provided that all normally hydraulically moved parts are manually operated together, for example, a covering itself and all components belonging to it, such as locking cylinders, covering caps, locking mechanisms and the like.
REFERENCES:
patent: 3126706 (1964-03-01), Dettinger
patent: 4343153 (1982-08-01), Kern et al.
patent: 5067768 (1991-11-01), Fischbach
patent: 5666809 (1997-09-01), Mentink
Dykema Gossett PLLC
Hoerbiger Hydraulik GmbH
Leslie Michael
Look Edward K.
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