FR2565616A1 - Device for raising mast elements and mast erected with the aid of such a device - Google Patents

Abstract

The invention relates to a device for raising mast elements. It is characterised in that it comprises a ring 11, one end 12 of which is cut off at right angles whereas its other end 13 is cut off obliquely at a dihedral angle B equal to the dihedral angle A of the oblique cut of the mast elements 2. Application to the transmitting equipment industry.

Description

 The invention relates to a device for lifting the mast elements and to the mast erected using such a device.

 It applies more particularly but not exclusively to the devices for lifting the elements of the masts intended to support and orient the transmitting and / or provisional receiving antennas used for both military and civil purposes.

 Due to the provisional nature of the installation of these antennas, it is known, to facilitate their transport, to produce these masts in several generally cylindrical elements which, during use, are placed end to end and are at each of these butt joints, assembled by engagement in one of the elements of a sleeve carried by the other element.

 For such a mast, we start by assembling the head elements supporting the antenna, then we engage this group of elements in a vertical shaft bearing on the ground by a base.

 Then, to raise the antenna to the desired height, by the base of this barrel, the necessary additional elements are successively engaged and by this the head of the mast is gradually raised.

 Of course, to dismantle the mast, we proceed in reverse.

 To raise the mast head each time from the height of an element engaged in the barrel, a lifting device is mainly used, consisting of a support plate connected by a link to at least one winch calling the plate towards the base of the barrel.

 The plate offers at the base of the mast a support on a flat face with respect to which the axis of the mast is perpendicular.

 In its center, it carries a means of centering the base of the last element engaged.

 For masts whose elements are cut normally at their ends, these elements find a wide support avoiding making them undergo a stress per unit of surface which would be excessive.

 So that during assembly there is no particular orientation to give to the elements without, however, that subsequently there are problems in controlling the orientation of the antenna, it is known (FR-A- 2,393,129) to make masts with elements which, at each junction, have their ends cut at an angle, so as to ensure their self-positioning.

 It is therefore understandable that the last element theoretically presses on the plate only by a point of its bias cut and the pressure which is exerted at this point hastens the deformation of the element which, then, will hardly take support on other elements.

 In addition, this pressure no longer allows the element to rotate about its axis by friction on the plate and it is therefore no longer possible to orient the mast.

 A result which the invention aims to obtain is a device of the aforementioned type which, when lifting the elements whose base has a bias cut, ensures a distribution of the lifting force over the entire extreme surface of the element which reduces the pressure per unit area on the plate and allows their orientation.

 Is also a result targeted by the invention such a device which, with the same plate, allows the lifting of elements as well as bias cut as straight cut.

 To this end, it relates to the device of the aforementioned type, in particular characterized in that it comprises a ring, one end of which has a straight cut while its other end is cut obliquely at a dihedral angle of the same value as the angle. dihedral of the skew cut of the elements of the mast.

It will be clearly understood with the aid of the description below, given by way of nonlimiting example, with reference to the attached drawing which schematically represents
- Figure 1: the lifting device seen in perspective,
- Figure 2: the device -'ru in axial section.

 Referring to the drawing, it can be seen that the mast 1 is made up of elements 2, the ends 3 of which are cut at an angle at a certain dihedral angle "A" chosen so as to ensure self-positioning of the elements between them and a transmission of orientation movements.

 For lifting, under the lower end of the element 2, is supported a plate 4 which, by links 5 such as straps, is itself connected to at least one winch (not shown).

 The upper face 6 of the plate 4 is flat and carries in its center a centering means 7 such as a pin of axis 8 perpendicular to the upper face 6 of the plate and which fits in the axial housing 9 of the end lower 3 of the mast elements 2.

 According to an essential characteristic of the invention, the device comprises a ring 11, one end 12 of which has a straight cut while its other end 13 is cut obliquely at a dihedral angle "B" of the same value as the dihedral angle "A "of the skew cut of the elements 2 of the mast.

 According to another characteristic of the invention, this ring 11 is interposed between the end face 10 of each element 2 and the upper face 6 of the plate 4.

 Thanks to this ring 11, the element finds a support for its entire extreme surface.

 This ring 11 is simply engaged on the centering means 7 also it can be removed to release the plate for the rise of element of straight cut masts.

 The centering means 7 and the bore 14 of the ring 11 have shapes such that said ring 11 can rotate freely around the axis 8 of the mast 1.

Claims (4)

 1. Device for lifting the elements (2) of the mast (1) whose ends (3) are cut at an angle at a certain dihedral angle (A) chosen so as to ensure self-positioning of the elements between them and a transmission of orientation movements, the lower ends of which are, for lifting the elements, supported on the upper face (6) of a plate (4) which, by links (5), is itself connected to a winch and which, in the center of its upper face (6), carries a centering means (7) with an axis perpendicular to said upper face and which adjusts in the axial housing (9) of the lower end (3) of the element (2), this device being CHARACTERIZED in that it comprises a ring (11) of which one end (12) has a straight cut while its other end (13) is cut obliquely at a dihedral angle (B ) of the same value as the dihedral angle (A) of the bias cut of the mast elements (2).  2. Device according to claim 1 characterized in that the ring (11) is interposed between the end face (10) of each element (2) and the upper face (6) of the plate (4).  3. Device according to claim 1 or 2 characterized in that the ring (11) has a bore (14) of shape complementary to that of the centering means (7), which shapes are such that the ring (11) can be threaded and adjusted on the centering means (7).  4. Device according to any one of claims 1 to 3 characterized in that the centering means (7) and the bore (14) of the ring (11) have shapes such that the ring remains free to rotate around the axis of the centering means (7).