US3196991A - Mast - Google Patents

Description

July 27, 1965 R. L. JOHNSON ETAL 3,196,991

MAST

Filed May 4, 1962 5 Sheets-Sheet l Will 60 m 43 El. 55 1 i 1 INVENTORS,

RICHARD L. JOHNSON HENRY L. SCHIFF, deceased BY ZQON H. scmyminisfla'rrix ATTORNEY.

y 7, 1965 R. JOHNSON ETAL 3,196,991

' MAST Filed May 4. 1962 3 Sheets-Sheet 2 FIG? INVENTORS, RICHARD L JOHNSON HENRY L. SGHIFF, deceased BY RION RigyFF, dminisfmhx ATTORNEY y 7, 1965 V R. L. JOHNSON ETAL 3,196,991

MAST

Filed May 4, 1962 5 Sheets-Sheet 3 U U INVENTORS,

RICHARD L. JOHNSON HENRY L. SCHIFF, deceased yon H. scW, qdzinishmrix ATTORNEY.

United States Patent 3,196,991 MAST Richard 1.. Johnson, Red Bank, N.J., and Henry L. Schifi, deceased, late of Wall Township, Monmouth County, Nl, by Marion H. Schitt, administratrix, Freehold, N "1., assigncrs to the United States of America as represented by the Secretary of the Army Filed May 4, 1962, Ser. No. 192,611 1 Claim. (Cl. 189-26) (Granted under Title 35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment of any royalty thereon.

The present invention relates to extensible and retractable mast structures particularly adapted for use in supporting radio, television or radar antenna or similar devices.

An object of the invention is the provision of a tower or mast which may be readily transported from location to location, and which may be quickly and easily set up for use.

A further object of the invention is the provision of a mast which is of use to the mobile branches of military forces which require quick and efiicient installations and he removal of equipment with dispatch when the occasions arise.

A further object of the invention is the provision of an extensible and retractable mast which may be readily collapsed and may be compactly crated for shipment to other locations.

Another object of the invention is to provide a mast structure of this type with telescoping members which lock themselves automatically when brought into their extended position and which cannot be unlocked by the stress or strain produced by the forces acting upon the mast and/ or the antenna upon the mast.

It is a further object of the invention to provide a mast structure of telescoping rods which unlock themselves automatically by a combination of simple devices without regard to the strain to which the mast is subjected by gravity or by prevailing atmospheric conditions.

Another object of the invention is to provide a support mast having new and improved valve means for raising and lowering the same.

Other objects and features of the invention as well as the combination and construction of parts will be apparent from the following description and from the accompanyin g drawings in which:

FIGURE 1 is a side elevational view of a completely erected mast assembly illustrative of the invention;

FIGURE 2 is a side elevational view of the mast in its collapsed arrangement;

FIGURE 3 is an elevational view of the uppermost section of the mast;

FIGURE 4 is a cross sectional view of the uppermost section taken on the line 44 of FIGURE 3;

FIGURE 5 is a sectional View of the locking collar, with a partial View of a guy support ring, as seen when in locked position;

FIGURE 6 is a view of the locking collar of FIGURE 5 shown when open or unlocked;

FIGURE 7 is an elevational view, and partly cut away showing a mast section and its locking collar with its associated air valve;

FIGURE 8 is an enlarged diagrammatic view showing the operative positions of the locking bolt of the locking collar;

FIGURE 9 is a top plan view of an air valve forming part of the mast structure;

FIGURE 10 is a sectional view of the air valve taken on the line 19-113 of FIGURE 9.

3,196,991 Patented July 27, 1965 For an over-all picture of the mast reference is made to FIGURES 1 and 2 wherein the mast of the present invention is shown in extended and collapsed positions respectively. In FIGURE 1, the mast generally designated as 11, is made of a plurality of discrete mast sections 13, 15, 17, 19, 21, 23, 25, and 27 Each of said sections are of substantially the same length. However each section is of a smaller width than the section preceding it, so that the sections can be telescopically stacked as can be seen in FIGURE 2. The extensible mast 11 is supported on a base 29 by having the first mast section 13 adequately secured thereto. The section 13 also includes a port 31 which serves as an inlet for a pressure medium, such as air or a liquid, for raising the mast sections as hereinafter described. Also afiixed to the mast section 13 is a reel 33 provided with a handle for afiording manual operation of the reel. While a hand operated reel has been shown, it is obvious that a motorized reel can be provided. The reel 33 serves as a housing for a cable 35, one end of said cable being affixed to the shaft of the reel, while the other end of the cable is anchored into and within the mast section 27. The cable 35 includes a weight 37, in the form of a plumb beveled at each of its ends. The weight or plumb 37 is utilized in the operation and functioning of the locking collars when it is desired to lower the mast from its fully extended position as hereinafter more fully described.

Each of the mast sections 1325, and with the exception of section 27, is provided with a locking collar, generally designated as 39, adjacent to the top of each of said sections. Each of the collars are of identical construction, except for a reduction in size of the successive collars on the respective successive smaller width mast sections as is apparent from the inspection of FIGURE 1 which shows the successive smaller collar on the mast sections. One such typical collar, is shown in FIGURES 5 and 6 in respective locked and unlocked positions, and further shown, partially cut away, in FIGURE 7. In the views, as seen in FIGURES 5, 6, and 7, a portion of the fully extended mast structure between mast sections 17 and 19, and its associated locking collar 39, is shown. In this regard, FIGURE 7 shows the upper portion of mast section 17 which surrounds and is in locked telescopic relation with its next adjacent mast section 19. The locking collar 39 of the mast ection 17 is secured immediately adjacent to the upper rim of the section 17 and, as shown in FIGURE 7 serves to lock the next upper section 19. Such locked engagement of the sections 17 and 19 is eiiected by the engagement of a locking bolt 61, and a ring 41 that is aiiixed to the outer surface of the section 19. The ring 41 is provided with a slot 43 within which may be accommodated the locking bolt 61 referred to above, for securely locking the .mast section 19 in its fully extended position, as shown in FIGURE 7. It is to be noted that the ring 41 is spaced a short distance from the bottom of the mast section 19 so as to aiiord a-more stable and rigid confinement of the section 1% within section 17 when in locked engagement.

The arrangement of one of the locking collars 39 is shown in FIGURES 5 and 6. In the specific example shown in said figures of the drawing it is that collar between the mast sections 17 and 19. The collar assembly includes a one piece housing 45 secured adjacent the top rim of a mast section 17. The housing is suitably secured to the section by bolts 47 or any other means. The housing includes a fitting 49 through which a lubricant, such as grease or oil can be forced into and within the housing 45. The housing also includes a peripheral slot 51 within which are seated a pair of identical arcuate shaped locking arms 53, 55 which, in locked position as in FIGURE 5, substantially engirdle the mast section 19. The arms 53, 55 are pivotally mounted on pins 57, 59

. 3 which are confined in the housing 45. Forming part of the locking collar are springs 60 located between the secured ends of the arms 53, 55 and the housing which function to normally urge the free ends of the arms toward each other. When so urged toward each other, the discrete free ends of the separate arms do not abut, but are spaced from each other to form a gap 62 which is in register with an opening 64 in the housing. Each of the locking arms has aflixed therein the transverse floating locking bolt 61. The bolt61 is supported by a pin 63 that is confined within the housing 45. The pin 63 is in turn slidably engagable in a slot 65 in the locking arm 53 to permit said locking arm to be moved away from a mast section when the locking bolt is to be disengaged from its locked position as hereinafter described. 7 1

To elevate the mast structure described herein, use is made of a fluid pressure medium such as air, water or other liquid. In the specific embodiment shown use is made of air as the pressure medium, and in this regard we have devised a new and novel air valve to regulate the flow of air into the mast structure. Such air valve is shown in FIGURES 9 and and generally designated as 67. Each of the mast sections, except for the first secured section 13, has an identical air valve bolted, or otherwise secured, within the bottom end of the mast section as can be seen in FIGURE 7. The air valve 67 includes a cylindrical body portion 69 having a peripheral flange 71 about its top edge. gasket 73 to effect an airtight seal of the valve 67 within the mast section. The body portion 69 includes an inverted T shaped central cavity .75 which includes an enlarged base cavity 75A. The housing 69 further includes a plurality of tubular passageways one of which is shown, in cross section, as 77 and having areduced portion 77A. within each of said passageways are confined a ball 79, of metal or the like, having a diameter larger than the reduced portion 77A, but of smaller diameter than the main portion 77 of the passageway. By such arrangement the ball is free to ride in the portion 77, but constrained from escape from the housing as is evident from an inspection of FIGURE 10 of the drawing. The ball 79 is normally urged downward, as viewed in FIGURE 10, by' a spring 81. One end of the springSl abuts against the ball 79, while the other end engages the underside of a plate 83 in the upper part of the body portion 69. The plate is secured to the housing by four bolts, one of which is shown at 85. Theplate 83 includes a central opening 87 in register with the cavity 75 and a plurality of openings 89 each in register with the passageways 77, however of a diameter smaller than the passageway 77. Also'shown are a series of bolts 91 in suitable openings which are. used to secure the air valve 67 within a mast section. Within the body 69 is a-confined cavity 93 having a reduced portion 93A which is in open communication with the cavity portion 75A of the entral cavity 75. Within the cavity 93 is a ball 95 which is normally urged against the reduced portion 93A of the cavity 93 by a lightly tensioned spring 97, one end of which abuts against the ball 95 while its other end engages the underside of the plate 83. Extending through the side wall of the body portion69 and into the cavity 93 is a passageway 99 which allows for an egress of air during the lowering of the mast structure as hereinafter described.

In FIGURE 4 there is shown a sectional view of the topmost section 27 of the mast and the arrangement for securing the cable 35 and its plumb Weight 37. The mast section 27 is shown in extended position and securely held by the locking collar 39 of the preceding mast section 25. As earlier described one end of the cable is secured .to the reel 33, and the other end of the cable is secured adjacent to the upper end of a movable cylindrical block 191 that is adapted to ride within the mast section. Secured to the lower end of the block 1191 is one end of Beneath the flange is seated a sealing a spring 193. The other end of the spring 163 is secured to a fixed anchor 1635 within the mast section 27.

The steps in the raising of the mast structure from its collapsed position, as shown in FIGURE 2, is as follows. An air line is afiixed to fitting .31 to introduce an air pressure into the mast structure. As the air pressure increases, the first mast section 15 will be raised and carry along with it all the remaining sections in unison. At this time section 15 will be locked in section 13 as hereinafter described. As the air pressure is further increased, air will overcome the resistance of the several springs 51 inthe passageway 77 thereby forcing the ball 79 from its locked position and permit air to rush through the six passageways 77. In this manner air pressure is sufficientlybuiltup to raisethe next mast section and lock said section. The remaining sections of the mast are then separately raised in the same manner.

The manner in which anyone of the locking collars 39 function is as follows, typified by the collar on mast section 13.' As the section 15 is being separately elevated, carrying along with it all the other mast sections in unison, the cable 35 will begin to unwind from the reel 33 and be carried upward as the topmost section, to which the other end of the cable is secured, is being raised. As the mast sections are being raised, the plumb weight 37 will readily engage and begin to pass through the gap 62 between the spring loaded arms 53, 55 and urge said arms apart as shown in FIGURE 6. Momentarily thereafter the locking bolt 61 will engage the ring 41 of the section 15. Such engagement will further urge the arms apart. As the section 15is still being raised, ,the plumb weight 37 will have already passed through the gap 62 and the bolt will be urged into engagement with the slot portion 43 or the ring 41 to thereby lock and secure the section 15 within section 13. To assist in the alignment of the mast sections, each of the sections is provided with oppositely disposed keys 196 that engage keyways 107 in the housing 45. It will be apparent that each of the mast sections will be locked in similar manner. After the mast is fully extended as in FIGURE 1, the air line can be removed from the fitting 31. Any loss of air pressure from the mast structure will be of no import, since no reliance is made upon internal pressure to support the mast structure in its elevated position. The mast structure is held rigid by the system of locking collars 39 and guy supports extending from a guy collar 1179 alfixed to the housing 45. As seen in FIGURE 2, several such guy collars are provided to provide any desired number of guy lines that extend to the ground.

When the mast is fully extended the plumb weight 37 will be positioned above the locking collar of mast section 25. When it is desired to lower the mast to its collapsed position, the reel 33 is rotated to draw the cable 35 on to the reel. As the cable descends the plumb weight will travel through the gap 62 between the arms 53, 55 thereby urging said arms apart. Such movement of the armswill release the locking bolt 61 from engagement with the slot 43 thereby allowing the section 27 to fall.

As the mast section 27 is falling, any normal air pres-' sure within the section will be dissipated through the air valve by the air entering the cavity of the air valve then into the portion 75A. The air then flows, or is forced, through the reduced portion 93A of passageway 93. Such movement of air is suflicient to force the ball upward to overcome the pressure of spring 97. The

air is then free to escape through opening 99. This same action is repeated as each of the mast sections is unlocked from its secured position. By such means a gradual and controlled descent of the mast structure can ends adjacent said base section, each valve being operable by a pressure medium used for raising the discrete successive mast sections to their fully extended position, a

locking collar on each of said mast sections, said locking collar including a pair of opposed spring loaded arms pivotally secured to each section at the end thereof opposite the first mentioned end, said arms engirdling and securing the next mast section of smaller diameter as said mast structure is being raised, means for unlocking said collars to release the secured mast section therein, said means comprising a cable spaced from the mast sections and having one end secured within a reel on the base section and its other end secured within the topmost mast section, a wei ht fixed to said cable intermediate its ends, said weight being adapted to engage contiguous ends of said arms to open same into unlocking relationship With said sections as said mast sections and Weight are being raised and lowered.

References Cited by the Examiner UNITED STATES PATENTS 15 FRANK L. ABBGTT, Primary Examiner.

HENRY C. SUTHERLAND, JACOB L. NACKENOFF,

Examiners.

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