Anchoring device

Abstract

 The device (7) for anchoring a mast which is intended to carry an aerial comprises a tubular ring into which the mast is intended to be inserted. A screw is adapted to be screwed through a threaded hole in the ring such as to cause the end of the screw screwed through the ring to exert pressure against the mast. The portion of the screw situated outside the ring extends through a suitably tubular strut (12) extending in a plane tangetial in relation to the ring. The screw extends through the strut (12) at one end thereof whereas the opposite end of the strut is provided with means permitting anchoring on the roof, wall or the like. Suitably, a nut is screwed onto the screw in a position between the head of the screw and the strut for clamping the strut between the nut and the ring. The length of the strut (12) is preferably adjustable. In the embodiment shown three anchoring devices are mounted.

Description

[0001] The present invention refers to anchoring devices, in particu­lar a device enabling anchoring of masts, preferably antenna masts on house roofs, house gables and the like, the anchoring device according to the invention permitting adjustment of the mast tube in a desired direction, normally in the perpendi­cular direction.

[0002] Even if in most cases it is desirable that an aerial mast extends perpendicularly upward, if not for other reasons than aesthetic ones, it is of extreme importance for paraboloid aerials to provide a stable part adjusted in a predetermined position as a starting point for directing the paraboloid aerial towards various satellites in a satellite orbit at a very great distance ordinarily above the equator. From all points of view the mast intended to carry the paraboloid aerial is the preferred part for this purpose.

[0003] In Swedish patent application 86 04401-3 there is described a support for the paraboloid aerial proper as well as arrange­ments for adjustment of the aerial attached to the support. This known aerial support is intended to cooperate with a mast which is securely anchored in a vertical position.

[0004] The purpose of the present invention is to provide a stable anchoring of this mast. Both as far as work and cost for the aerial support and the mast support are concerned it is essential that both mounting and necessary adjustments are easily and securely performed and that both the mast and the aerial support cannot be inadvertently moved from the adjusted positions. The expert will understand that the invention is not limited only to its use as described here.

[0005] It is often desired to place aerials as high above the ground as possible in order to elimite the risk that objects such as trees, neighbouring houses or the like might shield the aerial and disturb the signals received thereby from satellites and other transmitters. Accordingly, it has become self-evident to mount aerials on roofs in positions where it is possible steadily to anchor the aerial masts. However, in particular modern bungalow roofs some times have a soft structure as far as the underlying construction is concerned so that this easily may move due to changing loads, while still complying with the requirements as far as bearing resistances are concerned due to the use of adequate roof timbering. Such roof constructions however often cause difficulties to find suitable places for mounting an aerial mast such as to guarantee a stable anchoring. In some cases a gable tip or a wall may constitute a preferable anchoring place for an aerial mast.

[0006] It is the purpose of the present invention to eliminate the above-mentioned problems. This purpose is achieved by an anchoring device of the type indicated in the claims from which also the characteristic features of the invention will appear.

[0007] Hereafter, the invention is described in detail by reference to the attached drawings in which

FIGURE 1 is a schematic partial view of an aerial mast mounted on the roof of a house using the anchoring device according to the invention,

FIGURE 2 is a schematic partial view, in part in section, of an anchoring device according to the invention,

FIGURE 3 is a schematic partial view of an aerial mast mounted on a house gable using the anchoring device according to the invention and

FIGURE 4 is a partial view of the anchoring means of the aerial mast according to Fig. 3 seen from above.

[0008] In Fig. 1 there is schematically shown a house roof 1 with the position of certain rafters 2, 3, 4 indicated. An aerial mast rests with its lower end on a plate 6 which in turn is non-­slidingly attached to the roof exactly on a rafter 3. At some height of the mast in the embodiment shown three anchoring devices 7 according to the invention are mounted each having a strut extending downwardly towards three different attachment positions on the rafter in question.

[0009] In Figs. 3 and 4 it is shown how an aerial mast 5 is attached to the gable tip of a house. The mounting substantially corre­sponds to the embodiment shown in Fig. 1 apart from the fact that all the anchoring devices 7 extend to the wall. In the embodiment shown five anchoring devices 7 are used the lower-­most of which extends from the lower end of the mast 5 in an oblique downward direction to the house wall thus forming the anchoring device which to the greatest extent carries the weight of the mast 5 whereas the other four anchoring devices 7 support the mast 5 in its mounted vertical position.

[0010] As substantially appears from Fig. 2, every anchoring device 7 comprises a tubular ring 8 having an inner diameter slightly larger than the diameter of the mast tube 5 to enable the ring 8 to be passed over the mast tube 5. On the outer surface of the ring 8 a head or nut 9 is weldingly attached around a hole in the ring and the threaded hole 10 through the head or nut 9 is radially directed. A comparatively strong screw 11 is screwed into the threaded hole 10 leaving a comparatively great portion of the screw 11 outside the head 9 when the end of the screw 11 has passed through the ring 8. The screw 11 extends through a square tube 13 forming part of a strut 12 through a pair opposed holes therein. Between the head 14 of the screw 11 and the square tube 13 a nut 15 is screwed onto the screw 11.

[0011] Though not shown in detail in the drawings, the struts 12 comprise two portions 13 telescopically shiftable within each other and adapted to be locked in relation to each other enabling the struts 12 to be adjusted to various lengths. At the outer ends the struts 12 are provided with suitably hinged attachment means for attaching the strut end to a roof, a wall or the like.

[0012] The anchoring device 7 according to the invention functions in the following way: After having inspected the place, such as a roof or a wall, where an aerial mast is to be erected and attached and after having formed an opinion concerning the forces that may be expected to act on the aerial carried by the mast 5, such as a paraboloid aerial having a large surface exposed to the wind, a decision is taken as to how many anchoring devices will be necessary to obtain sufficient structural strength of the anchoring construction. A suitable number of rings 8, in the cases illustrated respectively three and five, are passed over the mast tube 5 prior to erection.

[0013] During the assemblage on the roof 1 the rings 8 are passed over the free end of the tube 5 whereafter the tube is erected and the plate 6 is attached to the roof 1 on a predetermined place. Even if this is not shown in the drawings, plate 6 is angularly adjustable in relation to the mast tube 5 for adaptation to various roof inclinations.

[0014] When the mast tube 5 has been erected and the plate 6 has been attached, struts 12 are attached to the rings 8 by screwing, however, initially so loosely that the rings 8 with some friction may be turned about and shifted along the mast tube and the strut 12 may be swung about the screw 11 in question. The telescopic character of strut 12 permits the attachment of the free ends on suitable places on the roof 1, suitably centrally above a rafter and preferably therein, as shown, the strut extending in a tangential direction in relation to the ring 8.

[0015] The vertical adjustment of the mast tube 5 is suitably checked with the aid of a plummet line or a level. By having all the adjustments slightly locked but loose enough to move with slight force, the vertical adjustment may be brought about by forcing the mast tube 5 in the desired direction and when the plummet adjustment is correct the screws 11 are tightened, thereby definitely to establish the positions of the rings 8. Thereafter, the struts 12 are locked in the adjusted positions and the nuts 15 are tightened so that no parts remain movable and the aerial mast 5 maintains the adjusted vertical position.

[0016] During the mounting of mast tubes with the aid of both the device according to the invention and other devices it is obviously necessary that a person initially supports the mast tube 5 while the attachment is initiated. This particularly applies to the kind of mounting as shown in Figs. 3 and 4 where a person standing on a ladder performs the mounting while a person on the roof holds the mast tube 5 in proper position. Also in this case the adjustment is performed in part by the telescopic adjustment of the struts 12 and in part by turning the rings 8 about the mast tube 5.

[0017] The anchoring devices 7 according to the invention act in the mounted condition fundamentally as every strut does. Parabo­loid aerials, however, as mentioned have a large surface exposed to the wind and during heavy wind the anchoring of tube 5 will be exposed to large forces, not only bending forces tending to over-throw tube 5 but also as turning forces. Due to the fact that the struts 12 are attached at a point outside the mast tube proper, in particular turning forces are absorbed much better than in conventional constructions due to the fact that the struts are exposed in part to a pulling force and in part to a compressive force. When the anchoring is performed in such a way that the strut extends in radial outward direction from a ring or corresponding element the mast tube may be turned some degrees prior to the beginning of the extension of the struts. This turning involves a bending of the struts which after some times of use may be weakened to such an extent due to fatigue that the struts may break.

[0018] The construction according to this invention does not permit any turning at all of the mast tube 5 because the slightest turning movement of the tube will become a big movement at the outer portion of screw 11 and the anchoring is such that no movement at all is permitted. Thus, the stresses are sustained by the strut which is exposed to pulling forces.

[0019] Thus, in accordance with the present invention the purpose as initially indicated has been fulfilled and produced a versatile anchoring device of a type which is both simple, cheap and efficient. The expert on this field will appreciate that there are many possible variations of the device here described as an embodiment of the invention, such variations being intended to fall within the frame of the invention.

Claims

1. Anchoring device (7) for solidly anchoring an aerial mast (5) or the like on a foundation (1), said anchoring being restricted to certain places on the foundation, characterized by a ring (8) enclosing the mast (5), a radially extending screw (11) adapted to be screwed into a threaded hole (10) in the ring, and a strut (12) through which the screw extends, said strut being tangential in relation to the ring (8), tightening of the screw (11) locking the ring (8) to the mast (5).

2. Anchoring device as claimed in claim 1, characterized in that a nut (15) is screwed onto the screw (11) in a position between the head (14) of the screw (11) and the strut (12), tightening of the nut (15) locking the strut (12) to the ring (8).

3. Anchoring device as claimed in claim 1 or 2, charac­terized in that the strut (12) is telescopically adjustable and adapted to be locked in the adjusted position.

Drawing