Expansible chamber devices – With releasable stop or latch means to prevent movement of... – Relatively movable working members with interdependent means
Reexamination Certificate
1999-01-13
2001-01-09
Lopez, F. Daniel (Department: 3745)
Expansible chamber devices
With releasable stop or latch means to prevent movement of...
Relatively movable working members with interdependent means
C092S068000, C092S136000
Reexamination Certificate
active
06170384
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a fluid power rotary drive device comprising a rotatably mounted output drive part, which has at least one ring of teeth, with which rack means, arranged on two juxtaposed drive pistons, are in engagement, the drive pistons being adapted to be oppositely moved by fluid actuation in two mutually parallel directions in order to cause a rotary movement of the output drive part between two end positions.
THE PRIOR ART
Owing to the presence of two drive pistons rotary drive of this type are referred to as double piston rotary drives. Their output drive part, which is generally designed in the form of a solid or hollow shaft, extends through and between the two drive pistons, with which it is engaged by gear teeth at a diametrally opposite peripheral position. By means of suitable fluid actuation it is possible for the drive pistons to be driven to perform an oppositely directed linear movement, something which in accordance with the selected direction of travel results in rotary clockwise or counter-clockwise movement. The angular displacement of the output drive part between the two end positions may be more or less than 360° in accordance with the maximum possible movement of the drive pistons.
SHORT SUMMARY OF THE INVENTION
A disadvantage in the case of rotary drive devices known to the assignee is the absence of any possibility of presetting intermediate positions of the output drive part. This means that the field of application is limited to certain uses. Accordingly the present invention is to provide a rotary drive device of the type initially mentioned which renders possible a positioning of the output drive part between the two end positions.
In order to achieve these and/or other objects appearing from the present specification, claims and drawings, in the present invention a position presetting device is provided, which by cooperation with the two drive pistons renders possible the presetting of an intermediate position, between the end positions, of the output drive part and for this purpose possesses an abutment unit having two abutment parts arranged adjacent to each other in an axial extension of the two drive pistons, such abutment unit being adapted to be moved in relation to the drive pistons into a positioning setting, in which the two abutment parts are simultaneously in contact with the respectively associated drive piston.
It is in this manner that the output drive part may be positioned not only in the two end positions but also in at least one intermediate position so that the rotary drive device has more extensive field of application. Because the position presetting means cooperates with the drive pistons, the toothed engagement between the output drive part and the drive pistons is not subjected to any higher load than in the case of a conventional design. The desired intermediate position may be simply set by displacing the abutment unit so far toward the drive piston that each drive pistons engage one of the abutment parts which are fixedly joined together. Owing to the existence of the toothed engagement there is therefore a closed force circuit, which renders possible a play-free fixation of the output drive part in the preset intermediate position.
Further advantageous developments of the invention are defined in the claims.
It is convenient for the abutment unit to be able to be shifted between the positioning setting and a home position, which is outside the maximum possible axial travel of the drive piston, the drive pistons in the home position of the abutment unit being able to be so positioned in their end positions by the action of pressure that the output drive part assumes the respectively associated end position.
It is convenient for the abutment unit to be located, when in the home position, outside the piston receiving spaces for the drive pistons, whereas in the positioning setting it has both abutment parts extending simultaneously axially into the two piston receiving spaces.
Preferably the rotary drive device so designed that a displacement of the abutment unit is possible using fluid force. For this purpose the abutment unit may have an actuating piston connected with the two abutment parts, which piston is acted upon by compressed air, for instance, for causing displacement. In order to be able to produce a compact design with a low height, it is an advantage for the actuating piston to have an elongated outline so that it is may be termed a flat piston.
The abutment parts are preferably designed like plungers and run in parallelism to one another so as to represent a coaxial extension of the respectively associated drive piston. They may be arranged with a transverse spacing between them on the common associated actuating piston. The fluid operation of the actuating piston may selectively be in accordance with a single acting or a double acting fluid power cylinder.
More particularly in order to permit fine adjustment of the intermediate position desired, it is possible for one or both of the abutment parts to have an abutment element, which may be adjusted in the direction of travel of the associated drive piston. In order, using simple means, to permit subsequent adjustment, it is possible for the abutment unit to have one or more cavities, which from the outside render possible an adjustment of the respective abutment element using a suitable tool such as a screwdriver or wrench.
It is furthermore an advantage if on leaving the positioning setting of the abutment unit there is an effective choking of spent air. This renders possible controlled movement of the abutment unit, when the output drive part is moved out of the intermediate position, jitter being avoided.
If the abutment unit is provided with at least one actuating member cooperating with a position sensor, there is the possibility of detecting the intermediate position reached by the output drive part via the abutment unit.
By mutual matching of the length of the abutment parts and of the drive pistons and their relative associations it is possible to select the intermediate position, which is to be preset, practically anywhere between the two end positions. An arrangement which appears to be particularly convenient is the presetting of a middle position, in the case of which the angular position assumed by the output drive part amounts to half the angle between the two end positions.
In the following the invention will be described with reference to the accompanying drawing in detail.
REFERENCES:
patent: 3019771 (1962-02-01), Heese et al.
patent: 3958493 (1976-05-01), Fujita et al.
patent: 37 41 261 A1 (1988-07-01), None
patent: 0 449 803 A1 (1991-10-01), None
patent: 2 138 505 (1984-10-01), None
patent: 63-19408 (1988-01-01), None
patent: 2-60704 (1990-05-01), None
patent: 3-121201 (1991-12-01), None
patent: 4-101809 (1992-09-01), None
patent: 5-223106 (1993-08-01), None
patent: 172167 (1965-06-01), None
Pfeiffer Dietmar
Stoll Kurt
Wagner Albrecht
Festo AG & Co.
Hoffman & Baron LLP
Lopez F. Daniel
LandOfFree
Fluid power rotary drive device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fluid power rotary drive device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fluid power rotary drive device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2521282