Static structures (e.g. – buildings) – With lifting or handling means for primary component or... – Mast or enclosure section elevated to superimposed position
Reexamination Certificate
2000-04-07
2001-10-16
Stephan, Beth A. (Department: 3635)
Static structures (e.g., buildings)
With lifting or handling means for primary component or...
Mast or enclosure section elevated to superimposed position
C052S745180, C052S749100, C052S118000
Reexamination Certificate
active
06301841
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method for erecting an emergency mast for a power line comprising mast elements placed one on top of another.
Emergency masts for power lines are used after one or more of the original masts have been destroyed by for instance a natural disaster such as an earthquake or tornado, another type of disaster or by sabotage. Emergency power masts can also be deployed to replace a faulty underground cable connection or as temporary connection to replace a cable or above-ground power line which is to be repositioned. There is therefore a need for a mast which can be erected quickly in such emergency situations. This mast can be used per se when only a single mast has been damaged by the disaster, or a series of masts can be used when a significant part of such a power line has been destroyed. Known from the prior art, for instance the KEMA brochure and ELECTRON “Emergency lines . . . , you may need them sooner than you think” is an emergency power pylon which is assembled lying on the ground and subsequently erected by means of a crane, by means of a pivoting hoisting boom or using a helicopter. It is also known to assemble a mast in the erected situation by mounting each of the subsequent elements on top of the already existing mast part using a boom suspended in cables.
All these known methods have drawbacks.
Assembly on the ground thus requires extensive lifting equipment which is usually difficult to take to the intended location and which requires much manpower. It is noted here that such emergency power pylons must usually be erected at locations which are difficult to reach and which are often not flat, so chat the available space is small and assembly and erection in this manner involve difficulties.
It is of course simpler to construct the mast elements by stacking, although this is dangerous because operations take place increasingly higher in the mast, wherein the mast elements must moreover be hoisted upward. This also requires the necessary lifting equipment and in particular the professional skill. In addition, the method is time-consuming because the guys must be constantly displaced.
GB-A 1 409 888 discloses a method for erecting a mast comprising mast elements placed one on top of another, comprising the following steps of:
arranging a lifting device at the location where the emergency mast has to be placed;
arranging a first mast element close by the lifting device;
raising the first mast element by means of the lifting device to a height such that a following mast element can be placed under the first mast element;
placing a following mast element under the first mast element and connecting the following mast element to the mast element situated thereabove;
raising the thus obtained combination by means of the lifting device to a height such that a following element can be placed under the combination;
repeating the latter two steps until the mast has reached the required height.
This known prior art relates to a temporary mast structure for a single radio mast or single signal mast.
The use as a temporary mast in a power line necessitates the use of several and sometimes large numbers of masts. The use of the prior art construction would imply the use of a separate lifting device for each of the masts. This is undesirable for logistic reasons.
BRIEF SUMMARY OF THE INVENTION
The aim of the invention is to provide such a method and the mast which result in a mast fit for a power line.
This aim is reached in that
the lifting device is located next to the location where the mast is to be erected;
the lifting device comprises at least one mast element from which at least two lifting frames extend, and
after the mast has reached the required height, the lifting device is removed.
These features result in the removability of the lifting device so that a single lifting device can be used for the erection of several masts leading to important logistic savings.
According to a preferred embodiment, suspension means for the high-voltage cables are arranged on the elements for placing high in the mast, while the relevant elements are situated at a low height adjacently of the guide device, wherein a work platform is also present.
This measure prevents that such usually heavy insulators forming the suspension means have to be handled by people at the top of the mast. This in any case involves dangers and requires much human effort.
According to another preferred embodiment, the mast elements are raised by means of a manually driveable winch mounted on the guide element. By choosing a winch of small diameter and possibly a transmission, the force necessary for pressing upward of the already partially mounted mast can be limited considerably. This has the advantage that this force can be exerted by manual effort so that no separate equipment is required for this purpose. This equipment is in any case not usually available in such emergency situations. It is also possible to make use of a light electric motor or a pneumatic or hydraulic drive.
It will be apparent that such an emergency mast will have to be guyed. It is noted here that the usual power pylons are not generally guyed; they take a wide form at their bottom. This is not possible with emergency power pylons; the components required for this purpose would be much too large or far too many components would be needed, whereby erection of such an emergency mast would take too long and require too much material. This is prevented by guying. Only after the mast has reached the final height are the guys fastened to their ground anchors and tensioned.
It is noted here that the guys are fixed to the mast elements by means of junction boxes which are also suitable for fixing of the insulating suspension elements.
The invention moreover relates to an apparatus for erecting an emergency power pylon formed from mast elements, comprising a frame for placing on the ground, guide means mounted on the frame at a distance from the ground at least corresponding with the height of the mast elements for guiding the mast elements of the power pylon for erection, and a winch mounted on the frame.
This apparatus is particularly suitable for performing a method according to the present invention; mast elements are herein placed and connected in each case to the mast element lying above, wherein the thus obtained assembly is pulled upward by means of the winch. Wound onto the winch for this purpose is a cable which can be coupled to the lowest mast element to be moved upward.
According to a preferred embodiment, the guide means comprise at least two guide sub-frames which are arranged at different heights on the frame and which are each adapted to enclose the mast elements. An adequate guiding of the mast elements thus takes place, which is necessary up to the stage at which guys are attached, since up until then the mast elements are only supported by the guide device.
According to another preferred embodiment, the frame is assembled from at least two mast elements. It will be apparent that this measure limits the number and variety of the components.
The present invention therefore provides a kit of parts for assembling at least one emergency power pylon, comprising at least mast elements and suspension means, and a guide device is included in the kit of parts.
In preference the kit of parts is placed in a closable container together with the mast components. The container can thus be taken quickly to the location where the emergency power pylon has to be erected. The container is provided for this purpose with all relevant parts. The container can be easily transported with usual transporting means, for instance a truck, train or ship.
REFERENCES:
patent: 1758389 (1930-05-01), Bushnell
patent: 2992710 (1961-07-01), Thomson
patent: 3495370 (1970-02-01), Habro et al.
patent: 4309854 (1982-01-01), Vendramini
patent: 4785592 (1988-11-01), Hung
patent: 4837992 (1989-06-01), Hashimoto
patent: 4932175 (1990-06-01), Donnally
patent: 5794387 (1998-08-01), Crookham
patent: 5833430 (1998-1
Rhebergen Bertus
Van Wolven Joseph Franciscus
Banner & Witcoff , Ltd.
Dorsey Dennis L.
N. V. Kema
Stephan Beth A.
LandOfFree
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