US2576389A - Telescoping tower - Google Patents

Description

Nov. 27, 1951 P. B. CRAEGHEAD ETAL 2,576,389

TELESCOPING TOWER Filed March 22, 1945 4 Sheets-Sheet l @WMMM 0 S N Z- E m. M. m 7 $1 H 2. B w

P. B. CRAIGHEAD ETAL 2,576,389

Nov. 27, 1951 TELESCOPING TOWER Filed March 22, 1945 4 Sheets-Sheet 2 0 50% mg N u n 13M ME 5 L, m r B 19 7' TOE/VHF.

Nov. 27, 1951 P. B. CRAiGHE'AD ETAL 2,576,389

TELESCOPING TOWER Filed March 22, 1945 I 4 Sheets-Sheet 5 :1 w muiua" 1951 P. B. CRAIGHEAD ETAL 2,576,389

TELESCOPING TOWER 4 Sheets-Sheet 4 Filed March 22, 1945 m G m N Z a w m M m i w w a fiTTOEA/EV.

Patented Nov. 27, 1951 UNITED; A ES PATENT OFFICE.

Philip B. Craighead, Milwaukee, and. George H. Nelson, Wauwatosa, Wis., assignors. to Safway Steel Products, 1110., Milwaukee, Wis., a corporation of Wisconsin ApplicationMarchZZ, 1945,,SerialNo. 584,216

1: Claim. (01. rac -14) This invention relates to. improvements in telescenic; towers and particularly to towers in which a. plurality of raising sections are lifted simul.- taneously. 7

It is. one object of the invention to provide a telescoping tower having av plurality of lifting sections nesting in a. base section in the lowered position of the tower and therefore occupy ng only the floor space required for thebase section.

Another object of the invention is to provide a rising; tower in which each; of the lifting sections; guided and raised by the action of the section immediately below thelifting, section under consideration.

Another object of the, invention is to provide atelescoping tower in which adjacent lifting; sec,- tions have thesame rate of rise relative toeach other.

Another object of the inventionis to provide a; tower having a plurality of; lifting sections coacting. inseries to secure a raising of all the lifting sections. simultaneously and to the; same extent relative to the preceding or lower section in the series, thereby securing the same degree of; raising ofall sections relative to each other at any given elevation.

Another object of the invention, i to provide a. raising tower in which the operating mechathe: sections are lifted by independent mecha-' nisms severally so related to adjacent sections above the first lifted. section as to:1ock any given section individually against downward movement beyond a predetermined extent in case of failure of any of the lifting mechanisms.

Another object of the invention is to provide a telescoping; tower which is. of, such lightweight and; such. small dimensions wh nin he: low r position. as; to; be readily. n r a h h. rapid; rate:- of simultaneous. li ting. of. all t the sections; can: be; obtained, and, in, whic imple operating; mechanism is employed. and; is:- divide into; portions singly lifting; each one-ofithe sectionsof: thetower.

Obiectsandadvantae s ther thanathosebov ,set forthwillbe apparent, from; the following des cripti qn..when. read, in connection with, the

: accompany g;dr Win n w h: p Fist. 1;. is; a: per-selective iew. o rthe tele cop c:-

tower of the. present, invention in the raised position;

Fig. 2 diagrammatically illustrates the nesting relation of the several sections of the tower to each other, the. relation of the operating mechanism. the tower base section to the first raising section,. and the relation of the operatingmechanism for lifting the several raising sections and theaction thereof in groups of three sections;

Fig. 3. is a topv plan View showing the. several lifting sections of the. tower in nested relation;

Fig. l. is. a side elevation of one of the lifting sections;

Fig. 5 is a sectional view of the base section of the tower, taken on the. plane of the line VV of Fig. 1, but omitting the wheels. and their mounting and the Outriggers of the tower;

Fig. 6 is an enlarged fragmentof a corner of the base section and the first lifting. section;

Fig. '7 is a section taken on the plane of the line VI-I-VII of Fig. 5;

Fig. 8 is a section on the planeof the line VIII-VIII of Fig. 5;

Fig. 9. is an enlarged fragment of one of. the lifting sections taken in elevation,.togetherwith a vertical section of a fragment of the; guide for such section;

Fig. 10v a section taken on a horizontal plane through theline X-X ofv Fig. 9;

Fig. 11 i an enlarged elevation of a portion of the raising mechanism of the several lifting sections above the first section; and

Fig 1-2 is-a section takenon avertical plane onthe line. XIL-XII of Fig. 1.1.

Theseveral sections are preferably formed generally of square tubing to minimize the weight of the structure, the several pieces of tubing being joined either by directly welding thepiecestogether or by means ofangles, plates, or other suitable joint-forming str-uctures. Generally the structure comprises a base, section and a plurality of lifting sectionswith. only the first lifting section driven directly from. operating mechanism mounted in the base section, and the remaining lifting sections being raised by. the section below. and, assisting in raising, the, next higher section. The sections are so dimensioned that. they nest in the base section. and; severally provide guides for the, succeeding orinner sections immediately adjacent, any given. section. The particular lifting. mechanism. disclosed reduces the weight of such mechanism toaminimum and causes simultaneous-.raising of. all-.sections, from the nested: position tothe: h ll; extended position of the tow-er and to the: same 'ings' for wheels 20';

degree and at the same rate for the various sections relative to each other.

Referring to the drawings by reference numerals, numerals II to I5, inclusive, severally and generally designate a base section and a plurality of lifting sections, the sections being numbered inv sequence from the base section to the last raising or the working platform section. It will be obvious that any number of raising sections may be employed if the base section is suitably dimensioned to give adequate working 1 space on the last raised section and if the interdependent portions of the structure are made of suificient strength to support the portions superimposed thereon. The base section II is shown as being constructed with a substantially square bottom frame of suitably joined structural shapes such as the channels I9 which are preferably extended at the four bottom frame corners to form mount- O-ther angles or channels 2 I extend across the bottom frame for stiffening the frame, and together with members 22 provide' a support for the'mechanism for operating the tower. The corners of the bottom frame I9 are reinforced by bars or angles 23 extending interiorly across the several corners of the frame and cooperating with the frame members in supporting portions of the operating mechanism. Uprights or posts 23 are erected on the bottom frame I9 at the corners thereof and are joined "by top rails 21 to former. substantially cubical frame. The frame sides are braced, at approximately the middle of the corner post heights,

byhorizontal braces 28 which are connected by diagonal braces 29 with the bottom frame I9 *andwith'the top rails 21. 1 An angle designated 30 is fixed in each of the inside vertical corners of the base section'to serve as a guide for the next section, which is the first raising section I2. A ladder 3| is fixed on one side of the base section which is also provided with outriggers 32 pivoted on the bottom frame I9 and the corner posts 26 and provided with screws 33 for securingground contact of the outriggers under 'all conditions to assure stability of the-tower prise vertical members or corner posts 31 joined by horizontal members or cross bars adjacent the top and bottom ends of the corner posts, and also at. approximately the center of such posts as indicated at 38, 39, and 40, the bars being braced by diagonally extending members M. It will be understood that the above mentioned frame members are preferably madeof tubing both for the purpose of minimizing the weight and to receive a portion of the operating mechanism in the case of the first lifting section. Each lifting section accordingly also forms a substantially cubical frame and is provided with a ladder 45 (see Fig. 1) on the same side of the tower as ladder 3| to allow climbing of the tower when at any elevation.

The lifting sections I2, I3, and I4 are also provided with angles 42 set into the interior of 4 the several vertical corners thereof to provide guides for the section nesting into another section. Thus the angles 30 of the base II provide guides for the first lifting section I2, theangles 42 of the section I2 provide guides for the second lifting section, and so forth. Each of the lifting sections I2, I3, and I4 has four cha'in'sprockets, generally indicated at 43, (shown in detail in Figs. 11 and 12) mounted on the top bars 38 adjacent the upper corners of the sections and 'also have four anchors 44 preferably mounted adjacent such sprockets to serve respectively as the carrying means for and as attachment points for some of the operating mechanism.

The first lifting section I2, in addition to the above structure common to the several lifting sections, also has a nut 48 mounted at or in the lower end of the several corner posts 31 and keyed as at 49 to the bottom bars to prevent rotation of such nuts. And the fourth or last lifting section has a working platform 52 secured thereon with a railing 53 about such platform.

The several lifting sections are connected with the base section and are interconnected by chains, indicated at 55, fastened at one end, for example, to the chain anchors 34 on the base, passing over the sprockets 43 of the first lifting section I2 and fastened at the other end to the bottom of the second lifting section I3 as by an anchor 46 to raise such second section. The driving-chainsfor the third lifting section I4 are fastened to thechain anchors 44 on the first lifting section I2 and pass over the sprockets 43 of the second lifting section and are fastened at one end to the bottom of the third lifting section. The interconnections for the remaining lifting sections are grouped in threes similar to the groupings described immediately above, as will be seen from the diagram in Fig. 2, and hence neednot be further described.

Driving mechanism for the tower is mounted 'on the bottom frame of the base section II, the

drive being shown as employing an electric motor 51 although any other power means or manual effort may be used to raise the tower. The motor 5'I-is connected by sprocket wheel 58 and chain 59 to a sprocket wheel 6|] mounted on a shaft BI from which power is taken to each of the four corners of the base section II to drive similar mechanisms. Each of such mechanisms includes a driving sprocket 62 for a chain 63 running over a sprocket 64 keyed on a shaft 65. The shaft 65 has keyed thereto a worm 66 within a suitable casing 61 mounted inthe inside corner of the bottom frame I9. The worm 66 engages a worm gear 68 fixed to the end of a screw 69 rotatably mounted in casing 61 and extending upwardly inside the vertical corner of the bottom section and through the nut 48 into the corner posts 31 of the first lifting section II. 1

The four drives 62 to 69, inclusive, are identical, and, being driven from the same source of power'at the same speed, simultaneously act to lift the first raising section I2. As the section I2 lifts, the sprockets 43 idle or roll underthe chains 55, and the reach of the chains between the anchors 34 and the sprockets 43 is lengthened, while the reach of the chain between the sprockets 43 and the bottom of the next raising section I3 is shortened. Such shortening of the latter reach of the chain lifts the second lifting section I3 within the 'first lifting'section- I2 and the two sections are therefore "raised simultaneously at the same rate and hence to the same degree relative to each other. The simultaneous action above described also takes place between the second and third and between the third and fourth lifting sections so that all of the sections rise at the same time and by the same amounts. It will be understood, of course, that the pitch of the screws 69 and the relations of the sprockets 43 and chains 55 are preferably so chosen that the rate of travel of the nuts 48 on the screws, and the rate of travel of the chains 55 over the sprockets 43 will produce the same amount of rise in the first lifting section and the succeeding lifting sections, respectively. It will also be understood that the number of lifting sections may be multiplied indefinitely, provided only that the dimensions of the tower are kept within practical limits and that the weight of the lifting sections, above the first lifting section, does not exceed the strength of the lowermost chains 55 on which all of the lifting sections l3, l4 and 15, above the first lifting section [2, are supported.

Even though the chains 55 are chosen with a sufliciently great factor of safety, it is desirable that each of the lifting sections I3, I, and I5 be provided with means coacting with the next lower section to prevent the dropping of such sections in the event of breakage of a chain under load or any other failure of any of the lifting mechanisms of such sections to operate properly. The means herein employed severally include a dog 12 mounted on a pivot 13, in each of the vertical corner posts 31 of the sections l3, l4, and I5, and having a nose 14 extensible into any one of several slots 15 cut through the guides 42 at regular spacings. One end of each of the several dogs 12 is connected by way of a chain 18 with the adjacent lifting chain 55, and such chains 18 severally hold the dogs in retracted position against the tension of a spring I9 extending between the end of each dog and a cross member 40 of the several sections. So long as the chains 55 are under load and taut, the chains [8 keep the dogs in the full line position shown (in Fig. 9) at which the nose 14 of each of the dogs is retracted into the corner posts 31, and the springs 19 are kept under tension. If the chains 55 become slack for any reason, the chains 18 also become slack and the springs 19 pivot the dogs 12 clockwise to project the nose 14 of each dog into the first of the slots 15 met by the dog in the downward movement of the section. In practice, the slots 15 are formed on approximately two inch centers, and it is hence impossible for the tower to drop farther than two inches upon any failure of a lifting mechanism.

It has also been found desirable in practice to interconnect the trunnions 8| of the sprockets 43 at the upper ends of such trunnions by a bar 82,

which serves as a guard for retaining the chain on the sprockets during all movement thereof and particularly to prevent twisting of the chain on the sprockets.

Although but one embodiment of the present invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claim.

We claim:

In a telescoping tower, a base section, a plurality of lifting sections nested within said base section, all of said sections being rectangular in plan and having vertical members at each corner, the adjacent vertical members of said sections cooperating to guide the sections when moving relative to each other, four jackscrews mounted on said base section adjacent the corners thereof and engaging the first of said lifting sections, power means mounted on said base section for simultaneously actuating said jackscrews to raise the first lifting section, chains interconnecting all of said sections and having rolling contact with the upper portion of I all lifting sections intermediate the base section and the last lifting section, said chains being anchored adjacent the corners of said sections to provide stability for each lifting section about any horizontal axis contained within the base of such section, dogs pivotally mounted on each of said vertical members on said lifting sections and adapted to operatively engage vertically spaced slots in the adjacent cooperating vertical members, means connecting said dogs to said chains to retain said dogs in an inoperative position when said chains are tensioned, and biasing means acting to move said dogs into operative engagement with said slots to prevent relative movement between the adjacent vertical members when said chains are not in tension.

PHILIP B. CRAIGHEAD. GEORGE H. NELSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 283,218 De Rycke Aug. 14, 1883 326,336 Sandberg et al. Sept. 15, 1885 401,623 Albert Apr. 16, 1889 483,001 Hughes Sept. 20, 1892 669,492 Gill Mar. 5, 1901 1,191,312 Jensen July 18, 1916 1,426,276 Christie Aug. 15, 1922 1,644,613 Royer et al. Oct. 4, 1927 1,684,181 Hopkins Sept. 11, 1928 1.924.506 Maier Aug. 29, 1933

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