US2351275A

US2351275A - Portable mast

Info

Publication number: US2351275A
Application number: US450479A
Authority: US
Inventors: Mcconnel Frederick Louis
Original assignee: Individual
Current assignee: Individual
Priority date: 1942-07-10
Filing date: 1942-07-10
Publication date: 1944-06-13
Anticipated expiration: 1961-06-13

Description

June 13, 1944. F L MC ONNEL 2,351,275

PORTABLE MAST Filed July 10, 1942 2 Sheets-Sheet l June 13, 1944. MCCONNEL 2,351,275

PORTABLE MAST Filed July 10, 1942 2 Sheets-Sheet 2 Patented June 13, 1944 UNITED STATES raTENT OFFICE PORTABLE. MAST Frederick Louis McConnel, Emporia, Va.

Application July 10, 1942, Serial No. 450,479

2 Claims.

The invention relates to a portable mast.

An object of the present invention is to provide a simple, practica1 and comparatively inexpensive portable mast, of great strength and durability, composed of laminated, cylindrical or other shaped sections of plywood or other suitable material and characterized by extreme lightness in weight.

While the mast of the present invention is especially designed to be utilized for supporting a radio antenna, it will be understood that it is not limited to such use, as it may be advantageously utilized as 'a flagpole, mast of a yacht, small ship or other boat, and for a number of other purposes.

It is inherent in a portable mast that it must be made of a number of sections, since it is not practical to transport the mast in its total length.

'Heretofc-re, various types of sectional and telescoping masts have been constructed utilizing metallic tubing of varying designs and materials. Many of these masts, however, are based upon the sections being joined by a telescoping joint. Such joints require accurate fits and further reduce the efiective height of the mast by the amount the sections overlap.

Also, various types of masts have been constructed utilizing wood sections joined by various means, and generally with one mast section overlapping another. Such a. mast has the disadvantage of being either weak at the joint, or the diameter or cross section of the mast must be invantages will be eliminated and which can be conveniently constructed without the necessit for accurate fits at the joints. With these and other objects in view, the invention consists in the novel construction, combination and arrangement of parts hereinafter described, illustrated in the accompanying drawings, and pointed out in the claim hereto appended, it being understood that various changes in the form, proportion andminor details of construction within the scope of the claims may be resorted to without departing from the spirit or sacrificing any of the advantages of the invention.

In the drawings:

Figure 1 is an elevation of a portable mast constructed in accordance with this invention;

Fig. 2 is an enlarged detail vertical sectional view showing a joint for mast sections of the same diameter;

Fig. 3 is a similar view showing a joint for mast sections of different diameters;

Fig. 4 is a horizontal sectional View taken substantially on line 4-4 of Fig. 2, and

Fig. 5 is an enlarged detail view of the anchoring means for the guys.

Referring particularly to Figs. 1, 2 and 4 of the accompanying drawings, the portable mast is composed of laminated, cylindrical mast sections 1, of uniform diameter. Each mast section is formed by cutting thin sheets of wood or veneer and wrapping and gluing the sheets to provide a laminated cylindrical wooden tube.

In order to secure the required strength and elasticity, the individual sheets 2 of veneer are wrapped so that the wood fibers in the adjacent sheets are arranged at right angles to one another in the well known manner of manufacture of the flat plywood board. The fibers of the adjacent sheets may be arranged at other angles, such as disposing the wood fibers in the adjacent individual veneer sheets at an angle of 45. Such wrapping and arrangement will increase the strength of the laminated cylindrical wooden tube.

The mast sections I, which are of the same diameter, are connected together by a joint comprising laminated semi-cylindrical wooden joint sections 3, spacing and shoulder-forming semicylindrical members 4, and sectional metal bands 5 and 6. The semi-cylindrical joint section and the semi-cylindrical spacing and shoulder-forming members consist of plywood tubes which are sawed diametrically so as to form two semicylindrical half sections.

The inner radius of the joint or coupling sections is equal to the outer radius of the mast sections to be coupled or joined together. These half sections will have approximately one-eighth of an inch planed or otherwise removed from their vertical edges 1 so that when they are placed around the mast sections to be coupled, they do not quite join or contact.

The metallic bands 5 and 6, which are preferably located at the center and at upper and lower ends of the joint or coupling, have the terminals 8 and 9 bent outwardly to form ears through which pass connecting or clamping bolts Ill. The bolts are adapted to clamp the couplings firmly about the mast.

The spacing and shoulder-forming semi-cylindrical members 4 are located at the inner faces of the coupling sections 3, at the central portions thereof, and their inner and outer faces are of the same diameter as the inner and outer faces of th mast sections which abut against the shoulders formed by the lower and upper edges of the members 4, as clearly illustrated in Fig. 2 of the drawings.

The spacing and shoulder-forming members 4 form a stop within the coupling, so that when the coupling is placed on a mast section, the members 4 will center the coupling between the two mast sections to be joined and will transmit the weight from the upper mast section directly to the lower mast section, thereby relieving the coupling sections and connecting bands of the vertical strain incident to the weight of the upper mast section.

Suitable bolts pierce the spacing and shoulderforming members, the coupling sections, and the sections of the central metal band 5 and do not pass through the mast sections, which are therefore not weakened by the bolts which secure the said portions of the coupling together. While three metal bands are provided for each coupling in 1 and 2 of the drawings, the number of the bands may, of course, be varied, and if desired, upper and lower clamping bands 6 may be secured to the coupling sections 3 in any suitable manner.

It has been found ample to provide guys l2 for the mast at every second coupling, as illustrated, and these guys may be constructed of wire, chains, or any other suitable flexible material or may be composed of sections linked together to provide for folding the ys.

Any suitable means may be provided for connecting the upper end of the guys with the couplings, and the guys at each coupling are preferably four in number and are shown provided at their upper ends with eyes [3 which are connected by links M with eye bolts l5, located at the center of the couplings and piercing the same between the mast sections.

The guys are preferably connected with anchoring member 16 by means of a short chain ll having its links engaged by suitable shackles 18 provided at the lower ends of the guys. The anchoring member l6 preferably consists of a screw formed by spirally winding a piece of metallic rod of the desired length and diameter.

The anchoring member I6 is provided at its upper portion with a straight shank I9 terminating at its upper end in an eye 29 which is linked into the lower end link of the chain H, but it may be connected with the lower end of the chain or in any other desired manner.

The eye 29 is designed to be of sufficient size to receive a bar adapted to form a handle to enable the anchor to be easily and rapidly screwed into the ground. The anchoring screw is capable of being screwed into every type of soil including rocky soil, unless such rocks are considerably larger than the cross sectional area of the anchor. It has been found by experiment that this corkscrew type of anchor can be readily installed in soil when the ordinary type of helical screw anchor cannot be used, the advantage of the corkscrew anchor being that it is adapted to adjust itself to the soil, due to its inherent elasticity. It is adapted to roll small stones out of its way or shift its position sufficiently to pass large stones, whereas the usual helical type anchor is stopped when it strikes a stone, unless the stone is small enough to be shattered by force.

If two or more guys are utilized on a mast, and if their length be fixed, they must be attached to an anchor which has a fixed distance from the base of the mast. It is usual to supply turnbuckles so that the length of the guys may be ad.- justed to set the mast in a vertical position and to take up slack or stretch in the guys.

However, when a large stone or boulder happens to lie at the point where the anchor should be installed, it may not be discovered until all the other anchors have been installed, and in an extremely rocky terrain, it may not be possible to find'a location where all four anchor points are clear of such large stones or boulders.

In such a case, it may be desirable to move the anchor either farther away or closer to the base of the mast in order to clear a boulder. This movement of the anchor may be such that the fixed length of a guy will not permit the necessary positioning of the anchor to clear such boulder even though adjusted to the fullest extent of the turnbuckle.

In order to take care of this condition, the chain I7 is fastened to the anchor I6. The chain is provided with sufiicient link openings that the pin of a shackle 18 may pass through any link of the chain. Each guy terminates at its lower end in a shackle l8 so that it may be fastened in any link of the chain, as determined by the length of the guy and the distance of the anchor from the base of the mast.

In Fig. 3 of the drawings is illustrated a coupling which is employed when the portable mast is composed of mast sections of two or more diameters. In this form of coupling, shoulderforming, semi-cylindrical, plywood members 2| and 22 are employed in addition to the coupling members 23.

The shoulder-forming members 2|, which are located at the center of the coupling, provide shoulders at their upper edges to receive the upper mast section 24 and the shoulder-forming members 22 are located at the upper portion of the coupling and their lower edges form shoulders to fit against the upper end of the lower mast section 25.

The upper and lower mast-sections are spaced apart by the shoulder-forming members; the sections of the inner shoulder-forming member 2| are secured by the bolts 26 of the coupling to the sections of the outer shoulder-forming member 22 and also to the coupling sections as the bolts 26 pass through all of these parts as well as through the sections of the central metal band 21.

It will thus be seen that the coupling shown in Fig. 3 is especially designed so that the bottom half of the coupling will fit the mast section of larger diameter, and the top-half of the coupling will fit the mast section of smaller diameter. The mast sections do not' have protuberances, either interiorly or exteriorly, and when the portable mast is made up of sections of a plurality of diameters, the smaller sections may be arranged within the larger sections to reduce the space required for stowage during transportation.

The portable mast is hinged at the lower end to a suitable base 28 and is'adapted to be swung upward to a'vertical position by a boom 29 and to be lowered by said boom from a vertical position to a horizontal position. The lower end of the portable mast is preferably stepped into a socket of a casting 3| or other metallic member which is hinged to the base 28 by a horizontal pivot or pintle 32.

The boom 29, which is designed to be constructed of plywood sections 33 is hinged at its inner end by a horizontal pivot 34 to the socket forming member 30. Suitable abutting shoulders or other means are provided for limiting the downward movement of the boom with respect to the mast, while the hinge joint is designed to be constructed to permit the boom to be swung toward the mast from a position at right angles to the same for folding the boom against the mast.

The outer end of the boom is preferably provided with an eye 35 for the reception of suitable means for securing the boom to one of the anchors. The base 28 may be anchored in any suitable manner and is designed to constitute a permanent portion of the mast. The boom is also preferably permanently hinged to the mast and is foldable against the side of the mast.

As one of the purposes for which the portable mast is especially designed is to support a radio,

antenna, and since such antenna must be connected to a transmitter or receiver by means of an electrical cable, the tubular mast sections will permit such cable to run through the hollow center of the mast. As the mast sections are spaced apart at their adjacent ends, the coupling may be provided with suitable means for supporting, at different points, a cable containing electric wires so that the upper end of the mast will not be subjected to the weight of the entire cable. Any suitable means may be employed for supporting wire-carrying cable at intervals, for instance, at every second coupling, or as may be required to relieve the top of the mast from the entire weight of the cable.

The mast can be constructed conveniently without the necessity for accurate fits at the joints, and by using the coupling without the necessity of overlapping at the joints. The mast is exceedingly light, the weight of the mast sections themselves being as light as one pound per foot in heights of 50 to 60 feet, and as little as an average of 1.3 pounds per foot in heights up to 75 feet. This is the approximate weight of the mast sections exclusive of guys and couplings. Experience has demonstrated that it is impossible to construct a portable mast of equal height and strength without exceeding these weights, if the mast is made as heretofore constructed.

What is claimed is:

1. A portable mast including a plurality of imperforate, laminated, plywood, tubular sections composed of thin sheets of veneer secured together by an adhesive and a coupling connecting the adjacent ends of the mast sections and comprising laminated plywood semi-tubular sections spaced apart at their longitudinal edges and arranged in overlapping and clamping relation with the ends of the mast sections and spaced apart at opposite sides thereof, spacing and shoulder forming semi-tubular members interposed between the ends of the mast sections and consisting of divided plywood tubes, said semi-tubular members being located within the clamping sections of the coupling and spaced apart at the spaced longitudinal edges of the coupling sections, intermediate and end metal clamping bands composed of sections having their terminals located at the spaced edges of the coupling sections, adjustable fastening devices connecting the ends of the clamping band sections and maintaining the coupling sections in clamping relation with the mast sections, and separate fastening devices piercing the intermediate band sections and the spacing and shoulder forming members and located between and spaced from the ends of the imperforate mast sections and securing the said spacing and shoulder forming members and the coupling sections together, the spacing and shoulder forming members being of material axial length andthe coupling being adapted to impart flexibility to the mast to per mit Whipping and bending of the same without breakage.

2. A portable mast including a plurality of imperforate, laminated, plywood, tubular sections of different diameters composed of thin sheets of veneer secured together by an adhesive and a coupling connecting the adjacent ends of the mast sections and comprising laminated plywood semi-tubular sections spaced apart at their longitudinal edges and arranged in overlapping and clamping relation with the ends of the mast sections and spaced apart at opposite sides thereof, inner and outer spacing and shoulder forming semi-tubular members interposed between the ends of the mast sections and consisting of divided plywood tubes, said semi-tubular members being located within the clamping sections of the coupling and spaced apart at the spaced longitudinal edges of the coupling sections, the inner sectional shoulder forming member corresponding in diameter to the smaller of two adjacent mast sections and having its upper edge forming a shoulder arranged in abutting relation with the adjacent end of the smaller tubular mast section and the outer sectional shoulder forming member surrounding the inner shoulder forming member and having its lower edge forming a shoulder seated upon the upper end of the larger mast section, intermediate and end metal clamping bands composed of sections having their terminals located at the spaced edges of the coupling sections, adjustable fastening devices connecting the ends of the clamping band sections and maintaining the coupling sections in clamping relation with the mast sections, and separate fastening devices piercing the intermediate band sections and the spacing and shoulder forming members and located between and spaced from the ends of the imperforate mast sections and securing the said spacing and shoulder forming members and the coupling sections together, the spacing and shoulder forming members being of material axial length and the coupling being adapted to impart flexibility to the mast to permit whipping and bending of the same without breakage.

FREDERICK LOUIS MCCONNEL.