GB2378055A

GB2378055A - Resiliant electrical connector

Info

Publication number: GB2378055A
Application number: GB0118370A
Authority: GB
Inventors: Jason Scott
Original assignee: Balfour Beatty PLC
Current assignee: Balfour Beatty PLC
Priority date: 2001-07-27
Filing date: 2001-07-27
Publication date: 2003-01-29
Anticipated expiration: 2021-07-27
Also published as: GB2378055B; GB0118370D0

Abstract

A multiple-section component has a connection block (50) between sections which has first and second faces (52,54) separated by a resilient material (56). A terminal (58) is provided in each of the first and second faces, and they are electrically connected together through the resilient material. In an assembled state of the multiple-section component, the connection block (50) is sandwiched between ends of the sections with electrical contacts (42) of the ends contacting a respective terminal (58). The connection block thus provides electrical connection between the contacts (42). The resilient nature of the connection block enables the contacts of the end portions to be flat, because the block enables contact to be maintained even if there is movement of the joint and even when there are slight differences in the separation between the end portions for different joints. This avoids the need for intricate connector designs, which are prone to damage.

Description

ELECTRICAL CONNECTOR This invention relates to electrical connectors, particularly for making electrical connections between signal conductors housed in adjacent sections of a multiple-section component, such as a shaft.

There are numerous applications in which multiple-section shafts are employed and in which a signal from a sensor at one remote end of the shaft must be relayed to the opposite end of the shaft. As one example, the auger piling process involves driving a multiple-section auger deep into the ground. The sections are assembled during the piling process. It is desirable to mount sensors at the auger tip, and signal conductors must pass along the length of the auger to relay the sensor signals to ground level.

Continuous flight auger piling has been used in the construction industry in increasing volume since the early 1980's. Piles are constructed by drilling to the required depth with a continuous flight auger mounted on a piling rig. During withdrawal of the auger, concrete grout or slurry is pumped into the excavated hole through the auger. A steel reinforcement cage may subsequently be lowered into the pile, either under its own weight or with the assistance of a vibrator.

During the initial boring stage, the auger is rotated into the ground at a rate intended to minimise the disturbance of the ground. The rate of advance of the auger during boring should depend upon the nature of the soil so as to cause this minimum disturbance. One indication of the nature of the ground is provided by measuring the torque on the auger during the boring process. This has conventionally been achieved by means of feedback signals from the drive motor.

During extraction, the rate of withdrawal of the auger should be controlled so that the appropriate amount of concrete can be delivered through the auger. The rate of extraction and the flow rate of supplied concrete also need to be controlled to prevent collapse of soil from the walls of the excavation, which would contaminate or otherwise adversely affect the concrete cross section. It is known to provide instrumentation at or close to the bottom tip of the auger to monitor the pressure of concrete at the auger tip. This requires a pressure transducer at the tip, and signal conductors passing from the tip (underground) to ground level. The joints between auger sections are subjected to a harsh environment including water, and some

movement at the joint is inevitable. Difficulties thus arise in establishing the electrical connection to the pressure transducer at the tip of the auger.

According to the invention, there is provided a multiple-section component comprising at least two sections, each section having an end portion provided with at least one contact, the two sections being mountable together such that the end portions oppose each other, the component further comprising a connection block, the connection block comprising first and second faces separated by a resilient material, a terminal being provided in each of the first and second faces, and the terminals of the first and second faces being electrically connected together through the resilient material, wherein, in an assembled state of the multiple-section component, the connection block is sandwiched between the end portions with each electrical contact contacting a respective terminal, such that the connection block provides electrical connection between the contacts.

The resilient nature of the connection block enables the contacts of the end portions to be flat, because the block enables contact to be maintained even if there is movement of the joint and even when there are slight differences in the separation between the end portions for different joints. This avoids the need for intricate connector designs, which are prone to damage. The connection block is the part of the connection which is most prone to wear. However, it can be made as a throwaway product, so that reliable connections can be guaranteed.

The resilient material preferably provides a waterproof enclosure for the electrical connections within the resilient part of the connector, so that the connections are protected from the outside environment.

Each end portion may be provided with one,. two or more contacts. For example two contacts may be provided and each face of the connection block is then provided with two terminals. This enables power to be provided to a remote sensor, as well as allowing a signal to be measured. The two contacts may comprise a first central contact and a second annular contact arranged concentrically with and around the first contact. This means the connection block can be inserted between sections when the sections are coupled together without being sensitive to the angular orientation. Instead, a central contact only could be used for carrying power and signals.

Each end portion may be provided in a recess at the end of the section, such that, in an assembled state of the multiple-section component, the connection block is housed within the recesses of the two assembled sections. The connection block is then sheltered from the outside of the shaft by the connection between sections.

The component may comprise a shaft, for example multiple-section auger. In this case, a sensor can be mounted at the tip of the auger, and signal conductors run along the auger sections, connected to the end portion contacts. The auger may comprise a core and a flight, the core comprising two concentric walls, and wherein the signal conductors pass between the concentric walls. The conductors may be for reading signals from a pressure detection device at the lower end of the auger.

The invention also provides a continuous flight auger rig comprising a multiple-section auger of the invention and a drive mechanism for driving the auger into the ground.

The invention also provides a connection block for providing electrical connection between end portions of adjacent sections of a multiple section component, the block comprising first and second faces separated by a resilient material, a terminal being provided in each of the first and second faces, and the terminals of the first and second faces being electrically connected together through the resilient material.

An example of the invention will now be described in detail with reference to the accompanying drawings, in which: Figure I shows a continuous flight auger piling rig, with two section of a multiple section auger assembled on the rig; Figure 2 shows the mechanical connection between sections in greater detail; Figure 3 shows the electrical connection of the invention in greater detail; and Figure 4 shows the layout of the connections.

Figure 1 shows an auger rig 10 of the invention for performing a continuous flight auger piling operation. The rig 10 shown in Figure 1 includes two section I la, 11 b of a multiple section continuous flight, hollow-shafted auger 11 which is rotatably mounted on a drive mechanism 12 which is in turn mounted for vertical movement on an upright pillar 13. The auger sections I la and I b may be two of many selectively attachable auger sections. Typically, each auger section will have a length of

approximately 6m, whereas the desired depth of the concrete pile will usually be between 10m and 26m. The auger sections are arranged to be attached to each other by appropriate couplings. Drilling the full length cavity will normally be performed in one stage, with the auger sections typically connected together prior to the commencement of the piling process. Alternatively, for very deep piling or to allow piling in limited headroom circumstances, drilling may be performed in incremental stages.

The drive mechanism 12 includes a depth encoder for determining the depth of penetration of the auger into the ground. Furthermore, concrete is supplied to the auger by a supply system which may include a flow meter.

A monitoring device 14 is provided in the form of a shaft which is coupled between the auger 11 and the drive mechanism 12 for rotation with the auger. The monitoring device 14 has a strain measurement arrangement providing strain signals which enable the rotational torque and/or axial force of the auger to be derived. This torque and force data can be used to control the rotational speed and/or the advance of the auger 11 into the ground as a function of the ground conditions.

The tip 19 of the auger is provided with a pressure detection device, and the signals from the detection device are provided to the surface (for example to the monitoring device 14) along cables running inside the auger sections. The pressure detection device is used during the extraction of the auger to ensure the presence of concrete at the tip 19. The invention addresses the problem of providing reliable electrical connections at the interface (or interfaces) 20 between auger sections.

Figure 2 shows in greater detail the coupling 20 between auger sections. The auger comprises a core 22 and a flight 24, and the core has two concentric walls 26, 28. The inner wall defines the passageway through which concrete is pumped, and signal conductors 30 pass between the concentric walls 26,28.

Each auger section is terminated with an end block 32. One end block is male, having a spigot 34, and the other is female, having a hexagonal bore 36. The coupling of the spigot and bore allow rotational torque to be transmitted between auger sections.

The conductors 30 pass through a passageway 38 in the end block and are terminated at an end portion 40 provided with a contact 42 for each conductor 30. The end portions 40 of the two sections oppose each other, and the contacts 42 are connected together electrically by a connection block (not shown in Figure 2).

The connection block is shown in greater detail in Figure 3. The connection block 50 has first and second faces 52,54 separated by a resilient material 56 which allows some flexibility in the distance between the faces 52,54. The resilient material 56 defines a cushion and comprises a rubber annular bellows in the form of a spring portion 56a and a sealing lip 56b. The lip 56b provides a waterproof seal so that the inside of the connection block is protected from the outside environment.

Terminals 58 are provided in each of the faces 52,54, and pairs of terminals 58 are electrically connected together through the resilient cushion 56 by wires 60.

The terminals 58 are positioned on the connection block 50 to align with the contacts 42, so that connected pairs of terminals 58 are for providing a connection between pairs of the contacts 42.

The end portions 40 comprise an insulating block 41 held in place using a retaining circlip 43.

When the multiple-section shaft is assembled, the connection block is sandwiched between the end portions. The end faces 40 are provided in a recess 60, so that the connection block is surrounded by the walls of the recess. This prevents water or other contaminant entering the connection area. The resilient cushion enables connections to be maintained despite movement of the joint, and also provides a watertight barrier to the inside of the connection block. Typically, the connection block has a diameter of around 30mm, and the diameter of the auger shaft is around 15cm. The cushion may allow the gap between end portions to vary by up to around 4mm.

The contacts 42 and the terminals 58 are flat contact pads, and can therefore easily be cleaned before assembling the sections together. The connections are also not prone to damage. Establishing a connection is easily achieved on site, as there are no intricate male and female components to connect.

As shown in Figures 3 and 4, the terminals 58 (and therefore also the contacts 42) are arranged as a first central terminal 62 and a second annular terminal 64 arranged concentrically with and around the first terminal 62. This enables the connection block to be inserted in any angular orientation. The block also has symmetry so that it may be inserted either way up.

Although the invention has been described in detail in connection with an auger, it may be applied to any sectioned component which needs to carry wires. For example, the invention may be applied to connections between drilling rod sections,

cone penetrometer rod sections, or for signal conductors extending through support structures such as precast or steel pile sections. For example, in the mining or oil exploration fields, it is often desirable to mount sensor devices at the ends of long probe devices.

Various modifications will be apparent to those skilled in the art.

Claims

1. A multiple-section component comprising at least two sections, each section having an end portion provided with at least one contact, the two sections being mountable together such that the end portions oppose each other, the component further comprising a connection block, the connection block comprising first and second faces separated by a resilient material, a terminal being provided in each of the first and second faces, and the terminals of the first and second faces being electrically connected together through the resilient material, wherein, in an assembled state of the multiple-section component, the connection block is sandwiched between the end portions with each electrical contact contacting a respective terminal, such that the connection block provides electrical connection between the contacts.

2. A component as claimed in claim 1, wherein each end portion is provided with at least two contacts, and each face of the connection block is provided with at least two terminals.

3. A component as claimed in claim 2, wherein the at least two contacts comprise a first central contact and at least one annular contact arranged concentrically with and around the first contact.

4. A component as claimed in any preceding claim, wherein the resilient material comprises an annular rubber spring with external lips which provide a waterproof seal.

5. A component as claimed in claim 4, wherein the connections between the terminals comprise wire connectors in a central hollow of the annular spring.

6. A component as claimed in any preceding claim, wherein each face of the connection block comprises a rigid insulating block.

7. A component as claimed in any preceding claim, wherein each end portion is provided in a recess at the end of the section, such that, in an assembled state of the

multiple-section component, the connection block is housed within the recesses of the two assembled sections.

8. A component as claimed in any preceding claim comprising a multiple-section auger, wherein a sensor is mounted at the tip of the auger, and wherein signal conductors run along the auger sections, connected to the end portion contacts.

9. A multiple-section auger as claimed in claim 8, wherein the auger comprises a core and a flight, the core comprising two concentric walls, and wherein signal conductors pass between the concentric walls.

10. A multiple-section auger as claimed in claim 8 or 9 further comprising a pressure detection device at the lower end of the auger.

11. A continuous flight auger rig comprising a multiple-section auger as claimed in claim 8,9 or 10 and a drive mechanism for turning the auger into the ground.

12. A connection block for providing electrical connection between end portions of adjacent sections of a multiple section component, the block comprising first and second faces separated by a resilient material, a terminal being provided in each of the first and second faces, and the terminals of the first and second faces being electrically connected together through the resilient material.

13. A connection block as claimed in claim 12, wherein each face is provided with at least two terminals.

14. A connection block as claimed in claim 13, wherein the at least two terminals comprise a first central terminal and at least one second annular terminal arranged concentrically with and around the first terminal.

15. A connection block as claimed in claim 12,13 or 14, wherein each face comprises a rigid insulating block.

16. A connection block as claimed in any one of claims 12 to 15, wherein the resilient material comprises an annular rubber spring with external lips which provide a waterproof seal.

17. A connection block as claimed in claim 16, wherein the connections between the terminals comprise wire connectors in a central hollow of the annular spring.