GB1601997A

GB1601997A - Remote-controlled apparatus

Info

Publication number: GB1601997A
Application number: GB19813/78A
Authority: GB
Original assignee: National Research Development Corp UK; National Research Development Corp of India
Current assignee: National Research Development Corp UK; National Research Development Corp of India
Priority date: 1978-05-16
Filing date: 1978-05-16
Publication date: 1981-11-04

Description

(54) REMOTE-CONTROLLED APPARATUS (71) We, NATIONAL RESEARCH DEVELOPMENT CORPORATION, a British Corporation established by Statute, of Kingsgate House, 6974 Victoria Street, London S.W.1, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention concerns remote-controlled apparatus and more particularly, but not exclusively, such apparatus for the remote operation of in-situ testing instruments in bore holes.

According to the present invention there is provided remote-controlled apparatus comprising a hydraulic piston-and-cylinder assembly operably connected to an electric motor by way of a screw mechanism, said motor, mechanism and assembly being serially located along the interior of an elongate substantially cylindrical casing, the free space within said casing being substantially filled with hydraulic fluid, and said fluid being contained within said casing partially by a flexible wall member externally exposed to the ambient pressure through said casing.

The proposed apparatus is suited to the above more particular application by serial connection of the motor, screw mechanism, and cylinder assembly which facilitates packaging in the cylindrical casing which, in turn, is compatible with passage through a bore hole, typi cally by way of a drill tube. For this purpose the screw mechanism is preferably of nut-andscrew form to assist in providing a transveresly compact structure.

The proposed apparatus is also advantageous in its use of hydraulic power to afford accuracy in the relevant powered operation of associated equipment, while allowing the hydraulics to be confined locally to the site of operation, electric power being passed between the control and operation sites to operate the motor. In these circumstances, it is also appropriate to employ electrical signals for relaying operating data between the sites.

For this last purpose the apparatus preferably comprises a pulse generator operable in response to rotation of the motor and screw mechanism, the pulse output of this generator indicating operational displacement in the cylinder assembly by reference to algebraic summing, and hydraulic flow rate by reference to pulse frequency. A limit switch operably connected to the screw mechanism is also preferably included to provide a signal which defines a datum position for the purposes of displacement.

The apparatus also preferably comprises a pressure transducer responsive to the interior of the cylinder assembly to provide signals whereby hydraulic output pressure can be monitored.

The fluid filling of the casing serves as a protection in relation to likely use in a flooded bore tube or in sea bed testing, and this fluid is subject to the ambient pressure by way of the flexible wall member. A pressure transducer is preferably provided for response to this fluid pressure. Also a variable volume reservoir internally communicated with the interior of the cylinder assembly and externally exposed to ambient pressure can be provided to compensate for remanent air in the assembly.

The above and other features of the invention will be clarified by the following description, given by way of example, of a presently preferred embodiment illustrated by the schematic, partially sectioned view thereof in the accompanying drawing.

The illustrated apparatus has an elongate circular-cylindrical casing 10 which houses, in one end portion, a hydraulic piston-and cylinder assembly including a reciprocatory piston 11 and a fixed cylinder 12. The cylinder communicates through a port 13 in the adjacent end of the casing with the end of a flexible hose 14 secured to the port, the hose leading to an associated equipment (not shown) to be hydraulically powered by the apparatus. This end of the casing is also formed at 15 for mechanical connection with the associated apparatus.

The piston 11 ls drivably connected with the nut component 16 of a nut-and-screw mechanism of recirculating ball lead screw form, and the screw 17 of which is drivablv connected, in turn, to the output shaft of a geared electric motor 18.

It will be seen that the motor, screw mechanism, and cylinder assembly are serially connected in coaxial alignment with the casing to provide a slim elongate package suited to passage through a bore hole or drill tube.

The motor and other electrical components mentioned bereinafter are hermetically sealed.

Also, the casing is substantially filled with protective hydraulic fluid except towards the upper end of the drawing where the casing houses a flexible reservoir 19 for such fluid, which reservoir is exposed through the casing to the ambient pressure.

A pulse generating switch 20 is operably connected between the screw 17 and the adjacent surrounding structure to provide an output which can be monitored to indicate hydraulic fluid displacement in the cylinder 12 by algebraic summing of the pulses. Also, in this connection, a limit switch 21 is provided for operation by the nut 16 when the latter is in a predetermined position so that the switch output indicates a datum for the displacement measurement. In addition, the frequency of the pulse output from switch 20 indicates the rate of hydraulic flow from the cylinder 12.

Operational data is also provided by a pressure transducer 22 communicated, by way of a pipe 23, with the interior of cylinder 12. This transducer and pipe are associated with a further pressure transducer 24 and a further small piston-and-cylinder assembly 25. This further assembly has its cylinder communicated with the pipe 23 and its piston exposed to the ambient pressure so that the latter can act on the assembly as a subsidiary reservoir to compensate for unvented air in the main cylinder 12. The pressure transducers 22 and 24 are respectively arranged to provide signals indicating the total pressure in the cylinder 12 and the difference between such pressure and the ambient pressure.

The pressure transducers and further cylinder assembly are suitably located, as shown, in a compartment between the motor and reservoir.

Additional electrical components necessary to transmission of operational data are also suitably located in this compartment, with such transmission, and electrical power for the motor, being provided by way of an armoured cable 26 extending from the end of the casing adjacent to the reservoir.

While the invention has been described with more particular reference to the illustrated apparatus, it will be appreciated that variation thereof is possible within the scope of the appendant claims.

WHAT WE CLAIM IS: - 1. Remote-controlled apparatus comprising a hydraulic piston-and-cylinder assembly operably connected to an electric motor by way of a screw mechanism, said motor, mechanism and assembly being serially located along the interior of an elongate substantially cylindrical casing, the free space within said casing being substantially filled with hydraulic fluid, and said fluid being contained within said casing partially by a flexible wall member externally exposed to the ambient pressure through said casing.

2. Apparatus according to Claim 1 wherein said screw mechanism is of nut-and-screw form coaxially aligned with said assembly and motor.

3. Apparatus according to Claim 2 wherein said nut is of recirculating ball form.

4. Apparatus according to any preceding claim comprising a transducer operable to provide signals representing displacement of said assembly.

5. Apparatus according to Claim 4 wherein said transducer is in the form of a pulse generator operably coupled with said screw mechanism to provide signals representing rotation thereof.

6. Apparatus according to Claim 4 or 5 comprising a limit switch operable to provide signals representing a datum position for said displacement.

7. Apparatus according to any preceding claim comprising a transducer operable to provide signals representing the fluid pressure in said assembly.

8. Apparatus according to any preceding claim comprising a transducer operable to provide signals representing the pressure of said hydraulic fluid.

9. Apparatus according to any preceding claim comprising a reservoir communicated with said assembly and operable in response to the ambient pressure to compensate the fluid content of said assembly for unvented air therein.

10. Remote-controlled apparatus substantially as herein described with reference to the accompanying drawing.

11. Apparatus according to any preceding claim in combination with a testing instrument to be hydraulically operated by said assembly.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. turn, to the output shaft of a geared electric motor 18. It will be seen that the motor, screw mechanism, and cylinder assembly are serially connected in coaxial alignment with the casing to provide a slim elongate package suited to passage through a bore hole or drill tube. The motor and other electrical components mentioned bereinafter are hermetically sealed. Also, the casing is substantially filled with protective hydraulic fluid except towards the upper end of the drawing where the casing houses a flexible reservoir 19 for such fluid, which reservoir is exposed through the casing to the ambient pressure. A pulse generating switch 20 is operably connected between the screw 17 and the adjacent surrounding structure to provide an output which can be monitored to indicate hydraulic fluid displacement in the cylinder 12 by algebraic summing of the pulses. Also, in this connection, a limit switch 21 is provided for operation by the nut 16 when the latter is in a predetermined position so that the switch output indicates a datum for the displacement measurement. In addition, the frequency of the pulse output from switch 20 indicates the rate of hydraulic flow from the cylinder 12. Operational data is also provided by a pressure transducer 22 communicated, by way of a pipe 23, with the interior of cylinder 12. This transducer and pipe are associated with a further pressure transducer 24 and a further small piston-and-cylinder assembly 25. This further assembly has its cylinder communicated with the pipe 23 and its piston exposed to the ambient pressure so that the latter can act on the assembly as a subsidiary reservoir to compensate for unvented air in the main cylinder 12. The pressure transducers 22 and 24 are respectively arranged to provide signals indicating the total pressure in the cylinder 12 and the difference between such pressure and the ambient pressure. The pressure transducers and further cylinder assembly are suitably located, as shown, in a compartment between the motor and reservoir. Additional electrical components necessary to transmission of operational data are also suitably located in this compartment, with such transmission, and electrical power for the motor, being provided by way of an armoured cable 26 extending from the end of the casing adjacent to the reservoir. While the invention has been described with more particular reference to the illustrated apparatus, it will be appreciated that variation thereof is possible within the scope of the appendant claims. WHAT WE CLAIM IS: -

1. Remote-controlled apparatus comprising a hydraulic piston-and-cylinder assembly operably connected to an electric motor by way of a screw mechanism, said motor, mechanism and assembly being serially located along the interior of an elongate substantially cylindrical casing, the free space within said casing being substantially filled with hydraulic fluid, and said fluid being contained within said casing partially by a flexible wall member externally exposed to the ambient pressure through said casing.