US2761531A - Sectional mast - Google Patents

Description

Sept 4, 1955 H. M. ANDERSON 2,761,531

SECTIONAL MAST Filed Feb. 19, 1951 2 Sheelts--Sheei'l 1 Sept. 4, 1956 H. M. ANDERSON SECTIONAL MAST 2 Sheets-Sheet 2 Filed Feb. 19, 1951 ,im fl-'DMAZM ATTORNEY United States Patent SECTIONAL MAST Harry M. Anderson, Fergus, `Ontario, Canada, assigner to Beatty Bros. Limited, Fergus, lOntario, Canada, a corporation ofCanada Application February 19, 1951, Serial No. 211,605

Claims. (Cl. 189-26) This .invention relates to a mast which is particularly adapted for supporting a television antenna at the required height for reception in the zone where the televisionreceiver is located.

'It is known that television waves travel in a straight line and do not follow the earths curvature. Thus, the .maximum distance at which `the receiving station can be located from the broadcast station, without making special provision for elevating the receiving antenna, is relatively small. By elevating the receiving antenna, receiving stations that arelocated on fringe of the normal range of the broadcast station or beyond 'the range may be brought within the-.range of the broadcast station. 'Ihere are, of course, obvious limits to which the antenna may be elevated.

The principal objects ofthis invention are to provide a mast for a television antenna which is light in weight; inexpensive to manufacture; easily transported to the siteon which itis to 'be erected, quickly and easily erected on the site; very rigidand strong.

It will be apparent, of course, that the mast will have other uses and accordingly it is to be understood 'that reference to its useasamast for a television antenna is for the sole purpose of illustrating the construction of the same and is not to be construed asa limitation thereof.

For an understanding of the inventionreference is to be had .to the following description and accompanying drawings in which:

Figure l is an elevation of a sectional .mast built up in situ from individual sections or units in accordance with this invention.

Figure 2 is cross section on the line 2-2 Fig. 1.

Figure 3 is a fragmentary elevation of the mast shown in Fig. 1, but on a large scale.

The television mast illustrated in Fig. 1 is formed of a plurality of units which are connected together in the manner hereinafter described to form a television mast of a predetermined height. It has been determined that the most suitable length of each unit is l0 (ten feet) and each side approximately l0" wide but the invention is not limited to those particular dimensions. Referring to Fig. l, it will be seen that the mast shown consists of sectional units A, B, C, D, E, F, and G, each being identical in construction and interchangeable one with the other. The construction of these units will be described subsequently. The height of the mast may be varied as required by adding additional units or using less than the number shown. It is felt, however, that the number illustrated is sul'lcient to provide an understanding of the invention.

Referring first to Figs, l and 3, it will be seen that the mast is supported on base which comprises a tubular post to which is attached three one piece brackets 11 projecting radially therefrom post 10 at equally spaced intervals. The outside free edge of each bracket is bent to form V-shaped vertical edge portion 12 to which the bottom unit A is attached in the manner hereinafter described. The post 1t) is supported on a base plate 13 to which it is pivotally attached by means of bracket 14 2,761,531 .latentedV Slept. v4,

erice and hinge ,pin 1S vpassing through the lower-Eend Dfthe post. Y

.Each unit comprises Vthree 'vertical girders '16 conf nected together by vhorizontal girts, 17.' Thexgirders are formed vfrom angle iron so that each :unitis V-:shaped in cross section. The girders and lgirts 'are `joined 'tof gether by welding to -form a very rigidlunitarysstrucnne. The girts are formed with an inwardly projecting; Hedge l18 which serves as a stitfener aswell as a support-.as hereinafter described. To obtain the -desired :rigidity for the mast, it is preferable to provide each unitiwith a plurality of girts arranged above eachother at :predetermined spaced `intervals .as shown. In the present/illus,i tration they are-spaced 18%, inches apart providing prop- 'erly `spaced rungs for the erector to ascend and .descend the mast. The girts adjacent each end of -eachunit are spaced inwardly from .-the .end so'that the ends of adjacent units willt into .one another as shown indetail in Fig. 3. It will be seen that the lowerend of the girders 16 yof unit Drtelescopically t inside the upper vendsof the girders 16 of the unit C and are supportedon Vthe .upper lgirts 17, Tothis end .lower ends of the girders are Vcloser together than at the top end, the distance being such .as toperrnit the lower ends of the girders to tit inside the upper ends of the, girders of vthe vnext lower unit. The ends of adjoining girders are connected together -by bolts 19 entered through bolt holes which are in line whenthe lower end of one section, rests -on the girtoftheinext lower section. This makes it unnecessary 'for the erectoli to 'hold the section while placing bolts. This arrange;r

` ment'is carried out throughout the assembly ofthe mast'.

The lower end of the girders 16 of the bottom unit A of the mast iit over the V-shaped portions 12. and are lconnected' thereto by bolts 27.

'In v.order to supportthe mast in van upright posi-tionjit v is necessary to provide guy Wires which can be attached to the mast at predetermined distances above ground level; 4For a mast of'approximately 4140 feet high, three lsets of guy wires are sufficient, `one at'the top, one about 40 feet above ground level, and the 'third Iabout midway between the two rst mentioned. To att-achY the guys to the mast, there is provided 'a triangular .shaped guy plate '205 which removably fits between the girders and is supported by the ledge 18 of 4'gir'ts :17. The guyplate plate 2f@ Iis' formed with lateral extensions 21, '22, Aand 23 projecting beyond the sides of the plate. The extensions 21, '22 are each provided with a hole Ito receive one guy wire 4while the extension 23 has two holes so that two guy wires may be attached thereto. Each guy plate is formed with a centrally positioned hole 2'4. Atta-chable at any gint is a triangular shaped ,centering plate 25 which has a central hole 26 therethrough registering with the hole 24. The shank of the antenna or the shaft for rotating the `antenn-a passes through the holes f2.4 and 26 which serve to centre lthe same and hold it in correct position. One centering plate for each unit will usually suthce.

The assembly of the mast yon the site is a relatively simple operation. Having determined the number of units required, the 'first step is to join together several lengths which form the lower part -of the mast, preferably up to where the rst guy plate will be placed. This be done with parts lying on the ground. The lower end wi'l-l be attached to base which 1in turn is hingedly connected Ito the base plate "13. A guy plate y20 is placed in the top end of the top of the assembled units (unit C in the present illustration) and the lower set of guy ropes 29, 29a, 29h, and 29C attached thereto. A length of the shaft for rotating .the antenna equal to the assembled .pant -is placed in position and centered by centering plates 25. The assembled parts are then swung to a vertical position and the guy wires secured to anchors 30. The

3 ereotor then ascends the mast .and step by step adds additional units until `a mast of the desired height has been erected. As the erection advances, the erector adds Vcentering plates, guy plates and antenna shaft as required, additional guy `wires such `as wires 31, E31a, 31b and 31e are attached and secured in place. When the las-t uni-t 'has been put in place, the top guy wires (not shown) are attached to the top guy plate and the anchors. The television antenna i-s then mounted in place and connected to the rotating 'shaft (not shown). Since other ways of erecting the mast and as the manner yof erection erecting .the same does not form part of lthe present invention, it is to be understood that the foregoing manner of erecting Ithe mast is only given by Way of illustrating 'one rway in which it can be done.

Although the foregoing specication discloses a mast, triangular in cross section, it will be apparent that other shapes may be used, such as square in horizontal cross, but this, of course, would add to Vthe weight `and cost of the mast. Such modications however are contemplated as being within the scope of the appended claims.

What I claim as new and desire to protect by Letters Patent of the United States is:

1. A sectional mast comprising a plurality of detachable preformed, interchangeable units mounted on top of each other in end to end relationship, each unit comprising three uniformly spaced girders positioned equidistant from and substantially parallel to the Vertical axis of the mast and parallel to each other, upper and lower horizontal girts connected to the girders adjacent the upper and lower ends thereof, each girder projecting above the upper girt and below the lower girt, the lower projecting end of one unit being smaller than the upper projecting girder end of the next lower unit whereby the lower projecting girder end tits inside the upper projecting girder end of a contiguous unit, the lower projecting ends of the girders engaging against the girts to support the units in superposed position, and a bolt locking the telescopically tting ends together against vertical displacement.

2. A sectional mast comprising a plurality of detachable preformed, interchangeable units mounted on top of each other in end to end relationship, each unit comprising three uniformly spaced V-shaped girders positioned equi-distant from and substantially parallel to the vertical axis of the mast and parallel to each other, upper and lower horizontal girts permanently connected to the girders adjacent the upper and lower ends thereof, each girder projecting above the upper girts and below the lower girts, the lower projecting end of one unit being smaller than the upper projecting girder end of the next lower unit whereby the lower projecting girder end telescopically tits into the upper projecting girder ends of the next lower unit, the lower projecting ends of the girders of the upper unit engaging against the upper girts of the lower unit to support the units in superposed position, and a bolt locking the telescopically fitting ends together against vertical displacement.

3. A sectional mast according to claim 1 wherein there is provided a plurality of centrally perforated centering plates located at predetermined positions throughout the heighth of the mast and supported by the said girts, said plates being held against a lateral movement by the girders.

4. A sectional mast according to claim 1 wherein there is provided removable guy plates positioned at predetermined points in the mast and supported by the said girts, said guy plates being held againstV a lateral movement by the girders.

5. A sectional mast according to claim 1 including a base member comprising a post, brackets extending radially from the post and arranged to register with and receive the lower ends of the girders of the lowermost unit and bolts securing said brackets and the said lower ends of the girders together.

References Cited in the le of this patent UNITED STATES PATENTS 473,522 Pitt Apr. 26, 1892 1,174,501 Hughes et al. Mar. 7, 1916 1,486,444 Malmgren Mar. 11, 1924 1,506,984 Marshall Sept. 2, 1924 2,145,232 Bauer Ian. 31, 1939 2,387,120 Cohen Oct. 16, 1945 2,410,246 Scrivener et al. Oct. 29, 1946 2,429,009 Woolslayer et al. Oct. 14, 1947 FOREIGN PATENTS 41,822 Switzerland 1908 79,251 Switzerland 1918 205,744 Great Britain 1923 225,629 Great Britain Dec. 7, 1924 283,406 Great Britain Jan. l2, 1928 319,123 ltaly 1934

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