FIELD OF THE INVENTION

THIS INVENTION relates to the installation of stressing assemblies, particularly in civil engineering and mining. The invention provides a stressing device, a nose cone for a stressing device, a locking device for a stressing assembly, a locking assembly for a stressing assembly, a stressing assembly and to a method of installing a stressing device.

BACKGROUND TO THE INVENTION

Stressing is commonly used in civil engineering and mining applications, both pre- stressing and post-stressing. Stressing assemblies are provided which are then used on site to tension a tensioning shaft (or some other component), forming part of the assembly. The shaft could be a cable or solid rod. These shafts (or components) are designed to be stressed in accordance with predetermined parameters and it is a problem to ensure that they are, in use, tensioned in accordance with these parameters. These parameters are not automatically recorded.

As indicated above, one particular application is in underground mining where rock faces need to be stabilised and supported. In such applications support shafts should be tensioned to a desired axial tensioning load. Presently, this is achieved mechanically by means of a locking device that is arranged on the support shaft in use and which is adapted automatically to indicate once the desired axial tensioning load has been reached in the support shaft. Such automatic indicating is usually achieved by the use of a frangible load bearing component that ruptures at the desired axial tensioning load, thereby indicating to an operator of the stressing device that the desired load has been attained. The operator then terminates the stressing operation and the locking device then locks the tensioned support shaft.

The applicant has however found that the abovementioned conventional approach is economically unattractive in that it necessarily requires additional components to be manufactured for a range of specific applications and desired axial tensioning loads. Of course, this requirement is also associated with a cost disadvantage from an end user perspective, considering that different types of locking devices have to be purchased for different applications and desired axial tensioning loads.

The present invention seeks, inter alia, to address the abovementioned difficulties associated with the use of frangible load bearing components to specify, in use, the axial tensioning load that is applied to shafts on installation thereof.

SUMMARY OF THE INVENTION

IN ACCORDANCE WITH A FIRST ASPECT OF THE INVENTION, there is provided a stressing device for stressing a stressing assembly, which includes a reader for reading at least one installation parameter provided on a component of the stressing assembly. The stressing device may have a nose cone and the reader may be located on or in the nose cone. The component may then be a locking device of the stressing assembly. ACCORDINGLY THE INVENTION IN ACCORDANCE WITH THE FIRST ASPECT EXTENDS to a nose cone for a stressing device for stressing a stressing assembly, which includes a reader for reading an installation parameter provided on a component of the stressing assembly. Conveniently, the installation parameter(s) may be provided on a data carrier that is located on the component. Conveniently, the reader may be operable optically, using radio waves, electronically or mechanically, with the data carrier similarly being optical in nature, using radio waves, an electrical connection or mechanically operable. For example, the data carrier could have a bar code thereon, could include a radio frequency identification device ("RFID") or a near field communication device ("NFC"), could have an electrical connector or geometric variances (such as steps or grooves). The reader is preferably electrically operable. Accordingly, the stressing device may have a power supply for the reader, which may be a battery. Further the reader may provide an electronic data signal incorporating the parameter(s) and the stressing device, in particular its nose cone, may have an output means for supplying an output data signal. The data signals from the reader may be supplied to a display unit or a response unit, the stressing device then having such a display unit or response unit. It will be appreciated that the installation parameter(s) may be read automatically when the nose cone is brought into engagement with the locking device or the installation parameter(s) may be read before the nose cone is engaged with the locking device. For example, this may be accomplished by connecting the nose cone and the locking device in an electro-mechanical manner, to enable the reader to read the parameter(s). Further, the reader may be operable to read the installation parameter(s) directly, as indicated above, or indirectly. Thus, the installation parameter(s) may be read from the component by means of a reader that is incorporated in the nose cone of the stressing device or by means of a separate, portable auxiliary reader that is engaged with the component to acquire the installation parameter(s) and then connected to or with the stressing device to transfer the acquired installation parameter(s) to a reader in the stressing device. It will be appreciated by those skilled in the art that direct reading is preferred as then there is greater certainty that the correct installation parameter(s) will be used with the stressing assembly to be stressed.

THE INVENTION IN ACCORDANCE WITH THE FIRST ASPECT EXTENDS to a locking device for use in locking a tensioning member of a stressing assembly in a stressed configuration, the locking device including a machine readable data carrier that is arranged in or on the locking device and carries, or is capable of carrying, at least one machine readable installation parameter.

In one embodiment, the data carrier may be electronically readable and the parameter(s) may be electronically storable. The parameters may, in particular, include the magnitude of a desired stressing load at which the tensioning member is to be locked in its tensioned configuration by the locking device. Further parameters may be those associated with the various parts of the stressing assembly, such as the length and other dimensions of the tensioning member. The tensioning member may, in particular, be a shaft which may be a cable or rod.

When the tensioning member is flexible, such as a cable, the locking device may comprise a body with a passage through which the cable passes and a locking subassembly may be provided that is receivable inside the passage to lock, in use, the cable inside the passage and relative to the body.

It will be appreciated that the locking device does not have a frangible tensioning indicating component, such as a 'snap ring', which is designed to fail at the desired axial tensioning load to indicate to an operator that the desired load has been attained.

When the tensioning member is rigid, such as a rod, the locking device may typically be a nut, with the rod and the nut then having complemental screw threads.

In such cases the tensioning device may be a socket.

In one embodiment, the data carrier may be electronically programmable with the parameter(s) being electronically stored. The data carrier may, as indicated above, utilise radio waves and, in particular, may comprise a radio frequency identification device (RFID) or a near field communication (NFC) device. The NFC device may be either an NFC chip or an NFC tag. In another embodiment of the invention, the data carrier may comprise a barcode, in particular a 2D barcode. The data that is carried or capable of being carried by the data carrier may include, in addition to the installation data, manufacturing data and/or identification data. The data may be in the form of "read only", i.e. non-editable, data and/or in the form of "programmable", i.e. editable, data. The data may comprise both non-editable and editable data. Thus data such as manufacturing data and/or identification data (typically an order number, size, and identification number) may be non-editable. The editable data may typically comprise installation data, including at least the magnitude of the desired tensioning load, as well as, for example, the length and size of the tensioning member, borehole size and depth (when the support shaft installation comprises a rock bolt) etc. In practice, the non-editable data may typically be supplied by a locking device manufacturer, whilst the editable data may typically be supplied by a user of the locking device, being programmed into the data carrier by the user after purchase.

THE INVENTION ACCORDING TO THE FIRST ASPECT EXTENDS FURTHER to a locking assembly which includes a locking device and a locking subassembly as hereinbefore described.

THE INVENTION ACCORDING TO THE FIRST ASPECT EXTENDS STILL FURTHER to a stressing assembly which includes a tensioning member and a locking assembly as hereinbefore described. THE INVENTION ACCORDING TO THE FIRST ASPECT EXTENDS also to a method of installing a stressing assembly which includes reading at least one installation parameter from a component of the stressing assembly.

The parameter(s) may be read automatically or by operator intervention.

Thus, the installation parameter(s) may be read when a nose cone of a stressing device is brought into engagement with the component of the stressing assembly. Alternatively, the installation parameter(s) may be read by coupling the nose cone to the component in an electro-mechanical manner. As indicated above the component may be a locking device of the stressing assembly.

Further as indicated above, the installation parameter(s) may be read directly, or indirectly. Thus, the installation parameter(s) may be read from the component by means of a reader that is incorporated in the nose cone of the stressing device or by means of a separate, portable auxiliary reader that is engaged with the component to acquire the installation parameter(s) and then connected to or with a reader in the stressing device to transfer the acquired installation parameter(s) to the stressing device.

The read parameter(s) may be displayed to an operator of the stressing device or may be used to control installation of the stressing device. As indicated above the installation parameter may be read electronically, in a wireless or wired manner, optically or mechanically.

The method may include storing the installation parameter in a carrier that is in or on the component and may also further include storing a plurality of further parameters which are associated with the various parts of the stressing assembly.

IN ACCORDANCE WITH A SECOND ASPECT OF THE INVENTION, there is provided an axial stressing device for axially stressing a stressing assembly, which includes

an axial load applying mechanism; and

an axial load sensor for sensing the axial load applied, in use, to a locking device of the stressing assembly. In addition, the axial stressing device may have a reader as described above, for reading a desired installation load value. Alternatively, or in addition, the axial stressing device may have an input module for inputting, in use, a desired installation load value. The axial stressing device may further have a display for displaying, in use, the applied axial load as well as the desired installation load value.

Alternatively, or in addition, the axial stressing device may have a comparator for comparing, in use, the desired load with the actual load, and for providing a load reached signal when they are the same. The axial stressing device may then also have a notifier, which is responsive to the load reached signal, for providing a visual and/or audio notification for the operator that the desired load has been applied. Instead, or in addition, the axial stressing device may have a switch module, also responsive to the load reached signal, for automatically switching the axial stressing device off, or deactivating it, when the desired load has been applied.

The axial stressing device may still further have a data storage unit for storing, in use, the desired load and the applied load. The axial load sensor may be located in a nose cone and the invention in accordance with the second aspect accordingly extends to a nose cone for an axial stressing device for axially stressing a stressing assembly, which includes an axial load sensor for sensing the axial load applied, in use, to a locking device of the stressing assembly.

The nose cone may also have a reader as described above in connection with the first aspect of the invention.

FURTHER IN ACCORDANCE WITH THE SECOND ASPECT OF THE INVENTION, there is provided a method of installing an axially stressed stressing assembly, which includes

applying an axial load to the stressing assembly; and

sensing the axial load applied to a locking device of the stressing assembly. In addition, the method may include reading the desired axial load from a data carrier in or on the locking device, or inputting the desired axial load value, as described above. The applied axial load as well as the desired axial load may be displayed to an operator installing the stressing assembly.

Alternatively, or in addition, the desired load may be compared with the actual load and a load reached signal supplied when they are the same. A visual and/or audio notification may then be generated and supplied to the operator that the desired load has been applied. Instead, or in addition, the axial stressing device may automatically be switched off or be deactivated, when the desired load has been applied. A design load and the applied load may be stored. It will be appreciated that the actual applied load may be stored or it may be stored in some other form, for example as a percentage of the design load.

IN ACCORDANCE WITH A THIRD ASPECT OF THE INVENTION, there is provided a stressing device for stressing a stressing assembly, which includes a data storage unit for storing an installation parameter of the stressing assembly when it is installed.

More than one installation parameter may be stored and the installation parameters that are stored may include any one or more of the following: the desired load, the installed load, an identifier of the stressing assembly, details of the stressing assembly, the identity of an operator of the stressing device, the time of installation and information in regard to the installed location of the stressing assembly The stressing device may have a reader as described above with reference to the first aspect of the invention. Alternatively it may have an input unit whereby an operator may enter the desired load value, the identifier of the stressing assembly, details thereof and his identifier. It may also have a load sensor and comparator as described above with reference to the second aspect of the invention.

In addition the stressing device may have a clock and a position determining module.

The data storage unit may conveniently be electronically operable. The stored data may be transferable to an administration facility. This may be done in a wired or wireless manner. Thus the stressing device may have a port by means of which it may be connected directly or indirectly to an administration computer or it may have a transmitter for wirelessly transmitting the data to a receiver of the administration unit.

STILL FURTHER IN ACCORDANCE WITH THE THIRD ASPECT OF THE INVENTION, there is provided a method of installing a stressing assembly, which includes storing an installation parameter of the stressing assembly when it is installed. As indicated above, more than one installation parameter may be stored and the installation parameters that are stored may include any one or more of the following: the desired load, the installed load, an identifier of the stressing assembly, details of the stressing assembly, the identity of an operator of the stressing device, the time of installation and information in regard to the installed location of the stressing assembly

The desired installation parameters and other data may be read as described above with reference to the first aspect of the invention. Alternatively an operator may enter the desired load value, the identifier of the stressing assembly, details thereof and his identifier by means of an input unit. The applied load may be sensed and compared as described above with reference to the second aspect of the invention.

As indicated above, the method in accordance with the third aspect may include transferring the stored data to an administration facility, in a wired or wireless manner.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail by way of a non-limiting illustrative example, with reference to the accompanying diagrammatic drawings.

In the drawings,

FIGURE 1 shows, in three-dimensional cut away view, one embodiment of a nose cone of a stressing device in accordance with the invention; FIGURE 2 shows, in three-dimensional view, one embodiment of a locking assembly in accordance with the invention;

FIGURE 3 shows, in sectioned view the interoperation of the nose cone of Figure 1 with a stressing assembly having the locking assembly of Figure 2;

FIGURE 4 shows, in sectioned view, the stressing assembly in its stressed configuration;

FIGURE 5 shows schematically a circuit board with componentry, used with the nose cone; and

FIGURE 6 shows schematically a stressing device in accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings and in particular to Figure 1 , reference numeral 10 generally indicates one embodiment of a nose cone of a stressing device in accordance with the invention. The nose cone 10 is for use in axially stressing a cable tensioning member 100 of a stressing assembly 102 (as shown in Figure 4).

The nose cone 10 is similar in function to known nose cones, with a number of added components. Thus, the nose cone 10 has a front locating portion 12 that has a passage 14 therethrough in which a locking device 104 and locking subassembly 106 of a locking assembly 108 (shown in Figure 2) of the stressing assembly 102 are, in use, receivable, as shown in Figure 3, and a rear portion 1 6, that also has a passage 18 therethrough. The portions 12 and 1 6 are coaxially aligned, with the rear portion being engageable with a stressing tool, such as an hydraulic jack as shown in Figure 6. The front portion 12 has a reader 18 located in a groove in the passage 14, for reading installation parameters and other data from a data carrier 1 12 provided on the locking device 104.

The rear portion 1 6 has a load exerting face 20 at its inner end which bears against a hollow load cell 22 that is housed in the passage 14. As shown in Figure 3, in use, a front surface 24 of the load cell engages a load receiving face 1 10 of the locking device 104, with the locking subassembly 106 being received in the load cell 22.

The nose cone 10 further has a circuit board 26 located in an annular cavity 28 in the rear portion 1 6 and a battery 30 in a further recess in the passage 18. A transparent ring 32 is provided between the front and rear portions 12 and 1 6. A number of indicating LED's 34 (with reference to Figure 5) are mounted on the circuit board 26, aligned with the ring 32. Thus, in use, when the LED's 34 are energised, the light that they emit will be visible to an operator of the stressing device. The following are also mounted on the circuit board - a data storage unit 36, a processor 38, a comparator 40, a position determining device 42, a clock 44, a buzzer 46 and an output interface unit 48. The interface unit 48 is connected to a port 50.

With reference to Figure 2, it will be seen that the locking subassembly 106 comprises a plurality of known wedge members 1 14. It is emphasised that the locking device 104 does not have an indicator system, such as a snap ring or the like, although it does have the data carrier 1 12 located in a hole on the outer surface of a body 1 10 of the locking device 104. As indicated above, the data carrier 1 12 is an RFID or a NFC device. Further as indicated above, the desired installation parameters for the stressing assembly 102 are stored in the data carrier 1 12, together with other data such as an identifier of the stressing assembly 102 and parameters of the stressing assembly 102. It will be appreciated that the carrier could be a label with a 2D barcode thereon, which is adhesively affixed to an outer surface of the locking device 104, with the reader 18 then being an optical reader.

Referring to Figure 6, a stressing device in accordance with the invention, in the form of an hydraulic jack 200, is shown. The jack 200 has a nose cone 10 as described above. The jack 200 further has a display 202, with two panels, a panel 206 for displaying the actual applied axial load and a panel 204 for displaying what percentage that is of the desired axial installation load value, as read from the carrier 1 12 by the reader 18. The jack 200 still further has a keypad 208 with keys 210, whereby an operator may input his identity and installation parameters such as the desired installation load value. In addition, the jack 200 has a control switch 212.

In use, the stressing assembly 102 is inserted into a hole, in known manner. The cable 100 is threaded through the nose cone 10 and the rest of the jack 200, also in known manner, and the front portion 12 engaged over the locking assembly 108. In so doing, the reader 18 comes close to the data carrier 1 12 and the data stored thereon, including the desired installation load, is automatically read and stored in the data storage unit 36. The jack 200 is then enabled by means of the switch 212, with the operator being notified thereof by means of the LED's 34 and the buzzer 46. The operator then operates the jack 200, drawing the cable 100 through the locking assembly 108 with the axial applied load being sensed by the load cell 22. The stored desired load is compared with the actual load being exerted, and when they are substantially the same, the operator is notified, again by means of the LED's 34 and buzzer 46. The operator then switches the jack off, with the cable 100 being held by the locking subassembly 106 and the locking device 104 and disengages the stressing device from the stressing assembly. The stressing load and other installation information such as the date and time of installation (from the clock 44), the installation location (from the position determining device 42) are stored in the data storage unit 36, together with information about the stressing assembly. At the end of a shift, a cable or a portable memory device is connected to the nose cone 10 via the port 50 for onward transmission of the installation information to a processing computer located in an administration facility. It will be appreciated that the information could be transferred in a wireless manner by means of a Bluetooth transmitter or the like.