GB2171076A - Manipulable devices - Google Patents

Abstract

A manipulable device has a number of sections in sequence, adjacent sections being hinged about a single axis eg 27, 26, 29, 33. At least two of the axes may be non-parallel. Bowden cables are used to effect relative movement between sections. The cable sheaths eg 13b may be located in blocks eg 42 carried by the sections. A flexible duct 37 extends along the sections and facilitates and guides inspection of flexible elongate devices along the device eg cameras, tools, probes. The duct 37 may be transparent or have viewing windows so that regions outside the duct and the device can be seen eg through gaps 36 between sections. Movement of the cables may be controlled in response to means sensing said relative movement. <IMAGE>

Description

SPECIFICATION Manipulable devices This invention relates to manipulable devices.

European Patent Specification No 104589 describes a multiarticulated manipulator having a number of sections hinged together. Wires are respectively connected to the sections for effecting movement about the hinges. The wires are guided by passing through elements which extend across the sections.

According to this invention a manipulable device comprises a plurality of sections arranged in sequence, adjacent sections being hinged together each about a single axis, a plurality of actuators for effecting relative movement between adjacent sections, and a flexible duct which extends along and within the sections.

The actuators may comprise elongate elements having an outer sheath and an inner wire movable axially in the sheath, eg Bowden cables. The sheaths may be clamped to respective sections. There may be a plurality of winding drums respectively associated with the elongate elements. The actuators may be adapted for effecting said relative movement selectively in either of two opposed senses.

Thus each section may have two Bowden cables respectively arranged to pivot the section in opposed senses.

At least two of said axes may be non-parallel. Successive pivot axes may be parallel or inclined. The sections may have differing lengths between hinges.

The flexible duct may be clamped within the sections as may the Bowden cables.

The duct may be supported by members defining said hinge axes. Regions exterior to the duct may be viewed from inside the duct, and there may be gaps between sections so that regions exterior to the device can be viewed from within the duct.

The flexible duct may have viewing windows.

The flexible duct may be transparent.

The invention includes a manipulable device however defined.

The invention may be performed in various ways and one specific enbodiment with possible modifications will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a side view of a manipulator apparatus; Figure 2 is a view of part of Fig. 1 on an enlarged scale and partly in section; Figure 3 shows part of Fig. 1 in a different orientation; Figure 4 shows part of Fig. 1 in a further orientation; Figure 5 shows a spider; Figure 6 shows a sensor arrangement; and Figure 7 shows a side view of part of Pigure 6.

The apparatus 10 comprises support structure 11 on which are mounted a plurality of winding drums 12 each arramged to operate a respective actuating wire 13 referred to later.

A deployment tube 14 is mounted for axial advance and retract movement on structure 11.

The end of the tube 14 remote from the drums 12 is pivoted to a flexible -mechanism 16 comprising twelve rigid hollow links or sections hinged together, adjcent links being hinged together each about a single axis. Successive links (up to and including the ninth link) are pivoted about parallel axes. Thus the end of the tube 14 is pivoted to the first link 20 about axis 21; the link 20 is pivoted to the next link 22 about axis 23 parallel to axis 21, and so on. However, as shown in Fig. 2, the ninth link 24 is pivoted to the eighth link 25 about axis 26 which is parallel to the pivot axis 27 connecting the link 25 with the seventh link 28 (parallel to axis 21), but at right angles to the axis 29 connecting the link 24 with the tenth link 30. The axis 29 is parallel to the axis 33 connecting the link 30 with the eleventh link 34.The eleventh link 34 is pivoted to the twelfth link about an axis parallel to axis 29. In each case the pivot axis is defined by two hinges which are diametrically opposed.

Thus axis 29 is defined by hinges 31, 32 and axis 33 is defined by hinges 32a.

Numbering from the support tube 14 links one to nine are pivoted about parallel axes and links ten to twelve are pivoted about axes which are parallel to each other and at right angles to axis 21, link nine being pivoted to link ten (30) about an axis (29) at right angles to axis 21.

The links are part-tubular so that in the undeflected state (Fig. 2) the structure 16 presents gaps or apertures 36 in the side through which an inspection device can look outwardly. Extending along the links is a flexible inner tube 37 which may be of plastics and may be transparent or have transparent portions in its wall. The inspection device may be carried on a flexible elongate element inserted along tube 37.

The links can be moved relative to each other about the connecting hinges by wires 13. In the example shown the wires are formed by Bowden cables comprising a flexible outer sheath and a flexible inner wire cable movable axially in the sheath. The cables extend from the drums 12 through the tube 14 and mechanism 16. Thus in Fig. 2 one of the cables comprises outer sheath 1 3b whose end is secured in a pull block 42 secured in the link 28 and the end of the associated wire 13c is secured in a wire pull block 43 secured in the adjacent link 25. A diametrically opposed wire 13d whose outer sheath 13e is secured in a pull block 44 secured in the link 28 diametrically opposite the block 42 and the end of whose inner wire 1 3f is secured in a pull block 45 secured in the link 25 diametrically opposite the block 43.The two wires 13c, 13f are connected to the same drum 12 so that rotating the drum in the one sense will pull on wire 13c to pivot link 25 (and the links further from the tube 14) in said one sense and rotating the drum 12 in the opposite sense will pull on wire 13f to rotate the link 25 (and the links further from the tube 14) in said opposite sense.

One wire for pulling link 30 about axis 29 is shown as 13h and one wire for pulling link 34 about axis 33 is shown at 13k.

Thus as shown in Fig. 3, the mechanism 16 can be bent simultaneously about several of the pivot axes by pulling on various of the Bowden wires.

Two cable pull blocks are secured in the end of the tube 14, their associated wires being secured in blocks in the first link to enable pulling on the wires to cause pivoting about axis 21.

The provision of link 24 with orthogonal hinge axes allows the mechanism 16 to have biplanar movement.

A series of spaced spiders 70 guide the tube 37. The spiders provide hinge pins 71 on which the links pivot. Typically a spider may be made from two identical parts 72, 73 having flanges 74 spaced by spacers 75 with bolts 76 as indicated diagrammatically, Fig. 5.

Each spider may have opposed bosses 77 each formed with one or more apertures 78 through which the cables 13 may pass for guidance. The duct 37 may be supported in the spiders 70 by its outer corrugated surface engaging the inner surfaces 79 of the spiders.

There could be more than one flexible duct 37 extending along the apparatus.

The apparatus may be used to enable remote access and inspection for example of part of a nuclear reactor at locations to which access is restricted or tortuous.

The tubular serpentine skeletal structure or exoskeleton 16 can be moved by simultaneous or sequential operation of selected wires (and thus hinges).

Flexible elongate devices can be inserted along tube 37 and retrieved. These devices may carry at their ends tools or inspection devices which can be remotely operated by using the flexible device.

In modified arrangements the successive hinge axes between links are not all parallel but may be inclined to each other. For example successive hinge axes may be at right angles or other relative angles. More than one link 24 could be included in mechanism 16 which could have more than or less than twelve links.

The links may all have the same axial length between hinges or some hinges may be more spaced than others.

In a further arrangement the separation and relative inclination between adjacent links in a sequence of links may be selected to provide a dedicated device to meet the requirements of a specific access or insertion route for the mechanism 16.

The following are examples of equipment which can be extended or inserted along the tube 37: fibrescopes, small closed circuit television cameras, still photographic cameras, radiographic sources, sampling tubes, ultrasonic probes; applicators for, for example, couplants, lubricants, corrosion inhibitors, paints.

The apparatus can be relatively long in relation to its cross-section or diameter and provides multiple controlled articulations.

The links may be moved by actuators other than Bowden cables; for example the outer sheaths may be omitted if the wires are routed close to the axes of the link hinges through which they pass; electromagnetic, electrothermal, hydraulic or pneumatic actuators may be used in a variety of combinations.

Feedback transducers or other devices may be used to provide data on position and speed of movement of all or selected hinges to enhance control of the snake mechanism 16.

One or more of the central ducts 37 may be constructed from transparent material or be provided with viewing apertures, as may the hollow links, so as to allow a viewing device, such as a fibrescope, to 'look' out along the length of the device and its insertion route to ease insertion and more particularly retrieval in the event of malfunction.

In addition to providing a duct through which devices may be inserted with the 'snake' in situ, the snake can be used as a manipulator and the central duct used to carry services which may readily be changed for a variety of work heads (TV cameras, paint sprays, drills, grinders, cutters and welders for example); thus providing a versatile robotic system. Inspection, cleaning, welding and corrosion protection for example providing a useful combination of functions.

The device may also be used to provide a guidance duct for the insertion of cables, hoses for example via routes which are otherwise difficult to use.

A modular form of construction may also be employed. In this case a series of standard pivoted joints may be provided and subsequently assembled with standard diameter tube or other hollow sections to provide a series of links of various lengths and various angles between adjacent hinge axes so that a 'snake' may readily be configured for specific access routes and applications.

The winding drums 12 could be operated by hand or by electric motors or linear actuators may be substituted for the winding drums. In which latter case control means could be provided for operating the motors or actuators, for example in a predetermined manner. The control means could include a computer and it is desirable to provide signals indicating the relative positions of adjacent links. Conveniently such signals can be obtained using potentiometers, as in Figures 6, 7 for example where links A, 8 are hinged at 80 and link A carries conductive track 81 and link B carries wiper 82 cooperable with the track 81 to provide a voltage output signal on conductor 83 dependent on the relative angular position of links A and B.

The structure 11 need not be horizontal but could be inclined or vertical.

The links need not be circular in cross-section but could be rectangular or hexagonal for example.

The duct 37 need not be plastics but could take the form of a helical spring.

The sheaths of the Bowden cables may be omitted in which case the wires of the operating cables are slidable in supports mounted on the neutral axes of the various hinges.

There may be rollers in the mechanism 16 for assisting the insertion and withdrawal of the duct 37 for exanple rollers could be mounted on brackets or spiders holding the duct.

Claims (12)

1. A manipulable device comprising a plurality of sections arranged in sequence, adjacent sections being hinged together each about a single axis, a plurality of actuators for effecting relative movement between adjacent sections, and a flexible duct which extends along and within the sections.

2. A manipulable device as claimed in claim 1, in which the actuators comprise elongate elements having an outer sheath and an inner wire movable axially in the sheath.

3. A manipulable device as claimed in claim 2, in which the sheaths are clamped to respective sections.

4. A manipulable device as claimed in any preceding claim, in which the actuators are adapted for effecting said relative movement selectively in either of two opposed senses.

5. A manipulable device as claimed in any preceding claim, in which at least two of said axes are non-parallel.

6. A manipulable device as claimed in any preceding claim, in which the duct is clamped wihtin the sections.

7. A manipulable device as claimed in claim 6, in which the duct is supported by members defining said hinge axes.

8. A manipulable device as claimed in any preceding claim, in which regions exterior to the duct may be viewed from inside the duct, and there are gaps between sections so that regions exterior to the device can be viewed from within the duct.

9. A manipulable device as claimed in claim 8, in which the duct is transparent.

10. A manipulable device as claimed in any preceding claim, including means responsive to said relative movement for controlling said actuators.

11. A manipulable device substantially as hereinbefore described with reference to and as shown in Figures 1 to 4, or Figure 5, or Figures 6 and 7, of the accompanying drawings.

12. A manipulable device however defined.