NZ555764A - Mast lifting apparatus and method - Google Patents

Abstract

A mast lifting apparatus (1) for use in positioning and securing mast elements end on end to form a mast or tower. The apparatus includes a releasably attachable mast attachment block (3) adapted to support and guide a moveable beam (4) having a top end and, in use, to allow the beam to be raised relative to the mast attachment block that, in use, is attachable to a mast section. The top end of the beam is adapted with a pulley or sheave means (8), and a first means (11) adapted to lift a mast element into position and a second means (18) adapted for raising the beam.

Description

555764 *10056549550* Our ref: TEN001 Patents Form No. 5 No. 555764 Dated 8 June 2007 COMPLETE SPECIFICATION 40 MAST LIFTING APPARATUS AND METHOD We, TENERGY NEW ZEALAND LIMITED, a New Zealand company, of 12A Home Street, New Plymouth, New Zealand, do hereby declare the invention for which we pray that 45 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: 1 555764 MAST LIFTING APPARATUS AND METHOD TECHNICAL FIELD This invention relates to mast and column lifting devices. More particularly, but not exclusively, the present invention relates to a system, method and apparatus for erecting columns, towers and masts and the like.

BACKGROUND ART Masts and towers are used for a variety of applications such as supporting telecommunications transmitters and receivers, wind turbines, and weather reading apparatus 15 or otherwise. Erecting these masts and towers can be a cumbersome and onerous task, particularly with structures up to and over 100 metres in height in some applications. A conventional method of erecting a mast is by first assembling the mast and then anchoring the lower end to a pivotable base platform, and then using a large crane or mechanism to hoist the assembled mast up to a vertical position by rotating about the pivot base platform. This 20 method can be effective for large diameter masts of short length, but is a difficult task to accomplish with taller masts.

Another method of erecting a mast or tower is to assemble the mast by stacking sections of the structure together end on end. Variants of this technique include attaching a section under 25 the stack of previously assembled and stacked elements. This technique means that the section being added is always at the same space on the ground under the previously added section. However, the amount of force required to lift the mast increases with each section added, and the overall weight and mass increases making the task more difficult with tall masts. This technique therefore is most suitable for shorter mast lengths, and not particularly 30 suitable for taller masts. 2 555764 It is a non-limiting object of the invention to provide a mast lifting apparatus which overcomes at least some of the abovementioned problems, or at least to provide the public with a useful choice.

It is yet a further non-limiting object of the invention to provide a mast lifting system and method which overcomes at least some of the abovementioned problems, or at least to provide the public with a useful choice.

SUMMARY OF THE INVENTION According to a first aspect of the invention there is provided a mast lifting apparatus for use in positioning and securing mast elements end on end to form a mast or tower, the apparatus including a releasably attachable mast attachment block adapted to support and guide a moveable beam having a top end and, in use, to allow the beam to be raised relative to the 15 mast attachment block that, in use, is attachable to a said mast section, the top end of the beam being adapted with a pulley or sheave means, and a means of raising the beam and lifting a mast element into position.

Preferably the means of raising the beam and lifting a mast element into position includes a 20 first winch means. Advantageously the first winch means includes a winch drum and a plurality of pulleys configured and arranged to lift mast elements. Desirably the first winch means includes a motor means.

Preferably the beam is raisable using a second winch means, the second winch means having 25 straps attached to the attachment blocks at either or both ends of the beam or at any point along the working length of the beam.

Desirably the second winch means includes a crank handle for allowing, in use, the beam to be manually raised and lowered as required.

Advantageously a motor driven second winch means may be employed to carry out the winching operation. 3 555764 Alternatively the beam is lifted by utilising a rack and pinion mechanism.

Desirably the mast attachment block is adapted to slidingly retain the beam such that the beam, in use, is slidable through the attachment block and being adapted to guide and support 5 the beam.

Preferably the beam is of a sufficient length to ensure that the reach of the top end of the beam is at or higher than the length of the next mast element to be raised and secured in position on top of the mast.

Optionally a wireless communication means is provided to control the operation of the first winch means and/or the second winch means. It will be appreciated that various wireless means can be incorporated in the lifting apparatus to enable remote operation of the moving components of the apparatus. Any known form of sensing means, and wireless control 15 devices can be incorporated to carry out any one or more steps and operations of the invention.

According to a second aspect of the invention there is provided a method of raising a plurality of mast elements sequentially to form a mast or tower, the method including the steps of: a. b. c. attaching a mast attachment block to a first mast element that is secured to the base of the mast and raising a beam having a sheave pivotably attached to or adjacent the top of the beam, and raising and then securing the beam at a height that is higher than the length of the mast element whilst paying out a winch cable; driving a winch means configured and arranged with the end of a cable about the sheave to lift the second or next mast element up to the top of the beam, thus allow the second or next mast element to be secured end on end to the first or previously positioned and secured mast element; securing the top of the beam to the second or next mast element before repositioning the mast attachment block to the second or next mast element; and 555764 d. releasing the top of the beam and raising the beam before attaching the end of the cable to the next mast element to be raised into position on the top of the end on end stack of secured mast elements forming the mast.

BRIEF DESCRIPTION OF THE DRAWINGS Preferred and alternative embodiments of the invention will now be illustrated, by way of example only, with reference to the accompanying drawings in which: Figure 1: Shows a side view of a lifting apparatus 1 according to a preferred embodiment of the invention; Figure 2: Shows the lifting apparatus 1 of figure 1 being secured in position at the base of the first secured mast element 2; Figure 3: Shows the lifting apparatus 1 being used to hoist a second mast element 2; Figure 4: Shows the lifting apparatus 1 with the second mast element being secured in position on the first mast element; Figure 5: Shows the head of the lifting apparatus 1 being secured to the top flange 2a of the mast element and the attachment block couplings being repositioned to the highest mast element 2; and Figure 6: Shows the head of the lifting apparatus 1 being raised and being readied to hoist the next mast element to the top of the mast element stack.

DETAILED DESCRIPTION OF THE DRAWINGS Referring to the figures, a mast lifting apparatus, generally referred to as 1, according to a preferred non-limiting embodiment of the invention, is illustrated. 555764 The mast lifting apparatus 1 is configured and arranged to lift and support the stacking of mast sections or mast elements 2 to form a mast or tower sections to form a tower. For purposes of ease of description, and with the interpretation of terms in the claims, references 5 herein to a mast include references to a tower or to any other similar form of vertically disposed structure.

An advantage with this form of mast lifting apparatus 1 is that the components of the mast lifting apparatus 1 can be transported to relatively remote sites for the assembly of a relatively 10 high or tall mast and that the desired height of mast can be varied as required by calculating the number of mast elements 2 required to achieve the desired mast height.

The mast lifting apparatus 1 preferably includes a mast attachment base block 3 adapted to support and guide a moveable beam 4 that may be in the form of a davit beam. The beam 4 is 15 elongate and can be tubular in cross section, and can be adapted to slide in a reciprocal or linear motion through the attachment block 3. Desirably the beam may be rectangular or square in cross section, although alternatively it may be circular in cross section, or may optionally be of any other possible shape in cross section depending on factors such as, for example, the means of raising the beam 4 being employed. When in position and in use, the 20 beam 4 is desirably configured and arranged to be raised after each mast element 2 is raised and secured end on end on the stack of mast elements 2. It can be seen that the length of the beam 4 is advantageously longer than the length of a mast element 2.

The beam 4 can be raised by any known mechanical means, and in this embodiment a davit 25 base having a second carriage winch and pulley means 18 is provided with a top strap 19 and a bottom strap 20. The top end of the top strap 19 and the bottom end of the bottom strap 20 can be merely anchored to the top housing 9 and lower end of the beam 4. Other arrangements can include being affixed to top and bottom attachment points. The carriage winch and pulley means 18 may optionally be driven by a motor through a worm drive 30 gearbox, and employing a chain or double link web belt drive and winch mechanism.

Alternatively, the beam 4 may be raised by way of a rack and pinion arrangement, a gearing means, or by a cable and pulley system. It may alternatively be raised hydraulically. In the 6 555764 application of a rack and pinion system, a pinion wheel can engage a rack provided on the beam 4, and the pinion wheel may be rotated by a motor drive means, and may also desirably be remotely controlled using a wireless controller.

In this preferred embodiment the carriage in the form of an attachment block 3 is desirably made of steel sections and plates, and in this non-limiting embodiment a Teflon™ or low friction material block is provided offering low friction for moving the carriage unit or attachment block 3 up and down the davit, as required. The attachment block 3 is of such a length to provide suitable stability of the davit during operation.

The attachment block 3 desirably includes at least one, but may preferably include two or more, clamp arms in the form of mast attachment brackets 5 configured and arranged to releasably attach to a mast element 2 before the next mast element 2 is hoisted up into position. The brackets 5 may desirably be pivotably attached to the block 3 and can be 15 adjustable via a bolt driven side plate (not shown). With such an arrangement the brackets 5 can be located in a suitable position when attaching the brackets 5 to the mast element 2. Cleats may be incorporated in the method of attachment on the mast elements 2 during assembly. It will be seen in operation that the brackets 5 can be adjusted such that, irrespective of the diameter of each mast element 2, the brackets 5 will wrap about the 20 adjacent mast element 2 and centralise the block 3 relative to the central axis of the last element 2.

One form of attachment is to adapt the bracket to enable it to bolt to the top flange 2a of a secured mast element 2 as seen in figures 2 and 5. Optionally and desirably a stabilising link 25 or coupling 6 may also be configured and arranged to releasably attach to a mast element 2 for increased stability of the block 3 and beam 4 during use and to allow for adjustments to be made to ensure the beam 4 is aligned in a substantially vertically disposed orientation. Any known form of coupling or bracket means may desirably be employed in this system arrangement, and in this embodiment a clamp and/or a strap is used.

The block 3 is desirably provided with a beam locking means in the form of a locking pin 7 associated with a corresponding aperture located in or adjacent to the lower end of the beam 7 555764 4. The pin 7 can be used to secure the beam 4 to the block 3 when the beam 4 is raised to its highest position.

A rotatable pulley or top sheave 8 is provided at or adjacent the top end of the beam 4, and in 5 this embodiment of the invention a sheave housing 9 is attached to the top end of the beam 4, and the sheave 8 is rotatably mounted within the housing 9. In an alternative embodiment the top sheave 8 can be replaced with a number of smaller sheaves to reduce the weight and size of the top hat mechanism or top housing 9.

Advantageously the housing 9 is provided with a mast element attachment means desirably in the form of a flange plate or housing flange 15 adapted to allow the housing 9 to be secured to the highest secured mast element 2 during the installation process. The housing flange 15 is desirably provided with an open slot (not shown) in the housing 9 to allow, in use, the cable 10 to be removed horizontally in order to lower the lifting flange or hook 14 to the ground for 15 the next mast element 2 to be connected and lifted up into place.

Advantageously the mast elements 2 are hoisted up into position using a winch means. The winch means advantageously includes a suitable winch cable 10 that is fed from a winch drum 11. The cable 10 may optionally be a high strength polymer giving a nominal factor of 20 safety of 10:1, and it is seen that this type of polymer cable offers a lower potential for damage and mis-feeding on the winch drum 11 as the cable will lie flat and not need to be layered onto the winch drum 11. The cable 10 is fed about a base sheave block 12 and up over the top sheave 8 and can extend back down to the ground for use in lifting mast elements 2. Desirably the cable 10 can be optionally fed through the hollow cavity of the beam 4, and 25 the top end of the beam 4 is adapted to allow the cable 10 to extend into the sheave housing 9 and over the top sheave 8 from the central area of the beam 4. It will be appreciated that the cable 10 can be alternatively run outside the beam 4 and be fed into the sheave housing 9 and over the pulley 8, if desired.

Optionally the sheave 8 may be adapted with a gearing means that is associated with a sheave motor means 13 located in the housing 9 that, in use, can additionally drive and guide the cable 10 as it is raised and lowered. A suitable power source means can also be housed in the 8 555764 housing 9 for powering the motor means 13. The power means is desirably a rechargeable battery means.

It is seen in figure 2 that the main cable driving means for lifting a mast element 2 into 5 position is desirably a motor driven winch drum 11 adapted with sufficient torque and power to raise and lower mast elements 2 during installation or construction of a mast. Any form of power means may be employed, and desirably an electro powered or electro-hydraulic power means may be incorporated in the system of the invention. The winch drum 11 may advantageously be driven, for example, by a 1.5kW motor with variable speed and associated worm drive gearbox to provide braking with an irreversible drive ratio. A suitable winch drum 11 may be rated with a lift speed of between 15m/min and 30m/min, although winches operating outside those parameters may be employed. A variable speed winch that is fully controllable is considered advantageous.

Optionally the motor driven winch drum 11 may be adapted with a controller means having desirably a speed controller means that can be adapted with a wireless communications means using known technologies to be remote activated, as required. In this respect the full operation of the winch cable 10 can be desirably controlled remotely by a user.

As seen in figures 2 and 3, the winch cable 10 spools on the winch drum 11 and extends about the base sheave block 12 and up through or alongside the beam 4. The cable 10 then can extend up over the pulley 8 and down the other side of the sheave housing 9. A mast element attachment means, desirably in the form of a lifting flange or a releasably attachable hook 14, is provided at the end of the cable 10.

In operation, and in accordance with a second aspect of the invention, there is provided a method of assembling or erecting a mast or tower or the like using sections or mast elements end on end. The steps of one non-limiting embodiment of the invention are now described and illustrated in figures 2 to 6. As seen in figure 2, the beam 4 is partially raised, and the first mast element 2, shown with flanges 2a at both ends of the mast element, is attached to the mast base 16. Any known form of attachment may be applied, and in this example, apertures (not shown) are provided in the flanges 2a and positioned to correspond to adjacent apertures in the next mast element 2 being hoisted or raised into position, and wherein bolts are 9 555764 provided to attach the next higher mast element 2 to the lower previously positioned mast element 2. As illustrated in figure 2, the first mast element 2 can be manually located and bolted to the mast base 16. Then the mast lifting apparatus is mounted to the first mast element 2 by clamp arms by way of securing at least one, and preferably two or more, mast 5 attachment brackets 5 to the mast element 2. Desirably the attachment brackets 5 are adapted to be secured to the top flange 2a of the mast element 2. Desirably the stabilising link 6 is secured about the mast element 2 to ensure the lifting apparatus 1 is aligned correctly relative to the mast elements 2. The winch cable 10 is secured into position about the base sheave block 12. Alternatively this step can be taken before the lowest mast element 2 is attached to 10 the mast base 16.

The method can include the step a. of raising the davit beam 4 to a sufficient working height above the height of the mast element to be erected and simultaneously winding or paying out the cable 10 to accommodate the additional height of the sheave 8 and beam 4, as required. 15 The beam 4 can then be positively secured in place by any suitable securing means, and in this preferred embodiment a locking pin 7 secures the beam 4 to the attachment block 3. Then in step b. the winch cable 10 is released or paid out by operation of the winch drum 11 so the cable 10 and the section hook 14 are lowered sufficiently to allow a user to attach or secure the hook 14 to a second or next mast element 2. The winch drum 11 is then reversed 20 and the cable 10 is wound back to tension the cable 10 and then the second or next mast element 2 is lifted into the placement position end on end on the first mast element 2.

A tailing line may be used to assist in the raising operation of the mast element 2 and to ensure that the next mast element 2 does not impact on the mast. Once the mast element 2 is 25 raised into position, a user can then desirably secure and complete the flange joint between the flanges 2a of adjoining mast elements 2 using bolts or otherwise. This positively secures the davit to the top flange 2a so that the full weight of the davit of the apparatus 1 can be taken by the secured mast element 2 with minimal rotation of the davit beam 4 and carriage towards the mast 2. It will be seen that the davit should remain substantially vertically aligned when 30 the davit base carriage or attachment block 3 is released from the installed mast element 2 and repositioned. 555764 The next step c. involves repositioning the lifting apparatus 1 and in this step the hook 14 is released from the mast element 2 and the sheave housing 9 and davit is lowered using the winch so as to attach the flange stop or housing flange plate 15 to the top flange 2a of the second or next mast element 2. This action secures the top end of the housing 9 and beam 4 5 so as to enable the secured mast element 2 and hence the mast to support the full weight of the lifting apparatus 1 as the attachment block 3 is repositioned onto the next higher mast element 2. It will be appreciated by a person skilled in the art that the beam 4 can remain in a relatively vertically oriented position as the attachment block 5 and the stabilising link 6 are released from the lower mast element and raised to the point adjacent the top end of the 10 highest attached mast element 2 and reattached thereto. It will be appreciated that the winch cable 10 is wound out and wound in as required to allow for adjustments in the position of the beam 4 and the lifting apparatus relative to the mast base 16 that is adjacent the winch drum 11.

The final step d. in the repeating cycle for installing each of the mast elements 2 is to release the flange stop or housing flange 15 from the top of the highest mast element 2 and to raise the beam 4 to a sufficient height to clear the space required for placing the next mast element 2 on the secured lower mast element 2. When the beam 4 is raised or as the beam 4 is raised, the cable 10 and hook 14 are wound out from the winch drum 11 and lowered to the ground 20 or point at which the hook 14 can attach to the next mast element 2 to be hoisted up onto the stack of mast elements 2. The installation cycle can then be repeated for each of the mast elements 2 until the mast is fully erected.

It will be appreciated by one skilled in the art that as the mast elements 2 are secured into 25 position and the mast height is increased over a certain height, additional stays, guying systems and support wires and devices can be provided to increase the stability of the mast, if desired.

Removal of the lifting apparatus 1 from the assembled mast when all the mast elements 2 30 have been secured in position can be achieved by attaching a lowering post or bracket (not shown) to the top flange 2a of the highest mast element 2, and by advantageously using a tailing line to increase the safety margin. The release mechanism 17 is activated and the hook 14 is then attached to the lowering post and the lifting apparatus 1 can be lowered using the 11 555764 tailing line or the main winch line. To increase clearance of the lifting apparatus 1 from the mast as it is lowered, the sheave block 12 can be repositioned from the base. The sheave block 12 can be located a nominal distance of between about 2 to 5 metres from the mast base 16, or the attachment lines to the mast base 16 can be loosened to achieve a similar result in 5 lowering the lifting apparatus 1 at an angle to the vertical in order to avoid fouling on the mast or supporting guys or stays.

Advantageously it is considered that the mechanical operation of the beam 4, the pulley 8, and the winch drum 11 can be adapted to be desirably activated and controlled by a user 10 remotely using a wireless communication means with transmitters and compatible receivers suitably configured and arranged to communicate between components of the mast lifting apparatus 1 such as the first winch means or the winch 11 and/or the second winch means or the winch 18.

It is also considered optional and desirable to install in suitable locations, where appropriate, sensors or sensor means to provide feedback signals to a user, and as a trigger for starting and stopping functions of the method of the invention. For example, a sensor in the housing 9 can be configured and arranged to detect when the hook 14 is at its highest desirable point and trigger a stop signal to ensure the winch drum 11 stops winding in. Furthermore, sensors may 20 be used to position the block 3 when being raised to the desired point of attachment to the next mast element 2 as illustrated in figure 5.

It will be appreciated that the components of the invention, such as the winch drum 11, length of the cable, and length of the beam 4 will all be influenced by the dimensions and weight of 25 the mast elements, and the intended height of the mast. Different capacity components will be selected to accommodate the operational requirements of the mast lifting apparatus 1.

It is considered that the capacity of the mast lifting apparatus may be suited to a range of mast heights, although in some applications more than one lifting apparatus with different 30 operational capacities may be used. For example, masts up to about 70 metres in height can use a 160kg (SWL) rated mast lifting apparatus, and a higher mast can be installed using a 225kg (SWL) rated mast lifting apparatus with a larger davit section. Higher masts can be considered with the 225kg or with a higher rated lifting apparatus. 12 555764 It will further be appreciated that materials used for components of the invention include any suitable and durable materials, for example only but not limited to, timber, metal, plastics materials, fabrics, rubber, glass or any combination thereof.

Wherein the aforegoing reference has been made to integers or components having known equivalents, then such equivalents are herein incorporated as if individually set forth. Accordingly, it will be appreciated that changes may be made to the above described embodiments of the invention without departing from the principles taught herein.

It is to be understood that the above description is intended to be illustrative, and not restrictive. Additional advantages of the present invention will become apparent for those skilled in the art after considering the principles in particular form as discussed and illustrated. Thus, it will be understood that the invention is not limited to the particular embodiments 15 described or illustrated, but is intended to cover all alterations or modifications which are within the scope of the appended claims. 13 555764

Claims (14)

Claims:

1. 5 10

2.

3. 15

4. 20

5. 25

6.

7. 30

8. A mast lifting apparatus for use in positioning and securing mast elements end on end to form a mast or tower, the apparatus including a releasably attachable mast attachment block adapted to support and guide a moveable beam having a top end and, in use, to allow the beam to be raised relative to the mast attachment block that, in use, is attachable to a said mast section, the top end of the beam being adapted with a pulley or sheave means, and a first means adapted to lift a mast element into position and a second means adapted for raising the beam. A mast lifting apparatus according to claim 1 wherein the first means of lifting a mast element into position includes a first winch means. A mast lifting apparatus according to claim 2 wherein the first winch means includes a winch drum and a plurality of pulleys configured and arranged to lift mast elements. A mast lifting apparatus according to claim 3 wherein the first winch means includes a motor means. A mast lifting apparatus according to any one of the preceding claims wherein the second means comprises a second winch means, the second winch means including straps attached to the attachment blocks at either or both ends of the beam or at any point along the working length of the beam. A mast lifting apparatus according to claim 5 wherein the second winch means includes a crank handle for allowing, in use, the beam to be manually raised. A mast lifting apparatus according to claim 5 wherein a motor driven second winch means may be employed to carry out the winching operation. A mast lifting apparatus according to claim 1 wherein the beam is lifted by the second means including a rack and pinion mechanism. 14 555764

9. A mast lifting apparatus according to any one of the preceding claims wherein the mast attachment block is adapted to slidingly retain the beam such that the beam, in use, is slidable through the attachment block and being adapted to guide and support the beam. 5

10. A mast lifting apparatus according to any one of the preceding claims wherein the beam is of a sufficient length to ensure that the reach of the top end of the beam is at or higher than the length of the next mast element to be raised and secured in position on top of the mast. 10

11. A mast lifting apparatus according to any one of the preceding claims wherein wireless communication means is provided to control the operation of the first winch means and/or the second winch means. 15

12. A method of raising a plurality of mast elements sequentially to form a mast or tower, the method including the steps of: a.) attaching a mast attachment block to a first mast element that is secured to the base of the mast and raising a beam having a sheave pivotably attached to or adjacent the top of the beam, and then securing the beam at a height that is higher than the length of the mast element whilst paying out a winch cable; b.) driving a winch means configured and arranged with the end of a cable about the sheave to lift the second or next mast element up to the top of the beam, thus allow the second or next mast element to be secured end on end to the first or previously positioned and secured mast element; c.) securing the top of the beam to the second or next mast element before repositioning the mast attachment block to the second or next mast element; and d.) releasing the top of the beam and raising the beam before attaching the end of the cable to the next mast element to be raised into position on the top of the end on end stack of secured mast elements forming the mast. 20 25 30 555764

13. A mast lifting apparatus for use in positioning and securing mast elements to form a mast substantially as herein described with reference to any one of the accompanying drawings. 5

14. A method of raising a plurality of mast elements sequentially to form a mast in accordance with claim 12 substantially as herein described. 16