US1584691A

US1584691A - Tower

Info

Publication number: US1584691A
Application number: US660310A
Authority: US
Inventors: Franklin M Bowman
Original assignee: Blaw Knox Co
Current assignee: Blaw Knox Co
Priority date: 1923-08-31
Filing date: 1923-08-31
Publication date: 1926-05-11
Anticipated expiration: 1943-05-11

Description

F. M. BOWMAN TOWER Filed August :51 1925 2 Sheets-Sheet 1 May 11 ,1926 F. M. BOWMAN TOWER Filed August 31. 1923 2 Sheets-Sheet 2 INVENTOR Patented May 11, 1926.

UNITED STATES PATENT oFFicE.

. FRANKLIN M. BOWMAN, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 BLAW-KNOX COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF NEW JERSEY.

TOWER.

Application filed August 31, 1923. Serial No. 660,310.

The present invention relates to towers, such as are employed in engineering work for carrying transmission lines, and for signal and wireless work, and to poles, masts and similar structure, the term towers being employed herein broadly to designate structures of this general character. I

A tower, as ordinarily constructed, has four sides, the load being carried principally by members at the four corners of the tower extending longitudinally thereof from the top to the bottom of the tower. The four sides of such a tower are all alike, and each is stiffened by diagonal bracing.

An object of the present invention is to provide a tower which requires fewer structural elements than the above type of tower, while having the necessary strength to withstand the stresses to which it may be subjected in use.

In the usual four sided tower construc- 3 tion, it is customary'to carry the four coranchorage. A further object of the present invention is to provide a tower having the foundation portion thereof so constructed as to effect a saving in the amount of excavation and in the amount of concrete required in the usual four sided tower construction.

In the accompanying drawings there is shown, for purposes of illustration only, one embodiment of the present invention, it being understood that the drawings no not define the limits of the invention, as changes may be made in the construction therein disclosed without departing from the spirit of the invention or scope of my broader elaims.

In the drawings:

Figure 1 is a diagrammatic elevation of a tower embodying my invention;-

Figure 2 is a view of the tower taken at right angles to the view of Figure 1;

Figures 3 and 4 are fragmentary views, corresponding to Figures land 2, of the rower portion of the tower;

Figure 5 is a horizontal sectional view taken on the line VV of Figure 3, and

Figure 6 is a detail view illustrating the effect of broken transmission wires.

Instead of having four sides and four continuous vertical corner posts at the intersection of said sides, as in the usual tower construction, a tower constructed in accordance with my inventionhas only three sides. One side of the tower above the foundation is substantially the same as in the four sided tower construction, that is to say, it com prises continuous vertical corner posts 2 and 3 and diagonal bracing members 4. Each of the other two sides of the tower has all of its longitudinally extending members consisting of diagonal bracing members 5, said members being preferably arranged in pairs, the two members of each pair extending obliquely to and crossing each other intermediate their ends. r

The three sides of the structure are trussed at intervals by means of horizontal triangular frames 6 to which the ends of the members forming the continuous posts 2 and 3 and of the diagonal bracing members i and 5 are connected. The side having the diagonal bracing members 4 may also have horizontal truss members 7 intermediate the tri angular frames 6. These horizontal frames divide the tower structure into a number of superposed stages or sections each of which is triangular in shape at its upper and lower ends. At the extreme top of the tower the horizontal triangular frame may be omitted, thereby providing a slightly modified form of top stage or section of the tower in which two diagonal bracing. members 8 extend from the apex of the triangular frame 6 at the base of the section and are connected at their upper ends to the upper ends of the continuous posts 2 and 3. The frontface of this top section has two crossing diagonals 8.

It will be apparent from the above description that one face of the tower, namely, the front face, is composed of the vertical corner posts 2 and 3, diagonals 4 and 8 and

horizontal members

6 and 7, while each of the other faces of the tower is composed of

diagonals

5 and 8 and horizontal members 6.

l Vith a tower structure as described, the wooden cross arms, such as 9, 10 and 11, for carrying telephone or telegraph wires 12 and transmission lines 13, or the like, may prieferably be arranged as illustrated in Figures 1 and 2.

The ordinary stresses applied to a tower of this character are due to the pressure of the wind and to tension in the wires. Wind pressure tends to bend the tower so as to put the continuous post 2 in tension, and the continuous post 3 in compression, or vice versa. The forces due to tension in the wires tend to put the

diagonal members

5 and 8 in compression if the wire pull is in the direction of the arrow, Figure 2, and to put them in tension if the wire pull is in the opposite direction. If, however, a wire on one side of the tower should break on one side of a cross arm, and a wire on the other side of the tower should break on the opposite side of the cross arm, as illustrated in Figure 6, there would be a twisting moment applied to the tower, as illustrated by the arrows in said figure. A tower constructed in accordance with my invention is especially adapted for taking care of such twisting strains, as well as for taking care of the strains due to unequal tension in the wires, and to wind pressure.

In building a steel work tower of this character, degree angle members may be used for all of the main elements of the tower. hen such angle members are used, the members forming the corner posts 2 and 3 may be crimped at suitable places, as indicated in Figure 5, to receive the diagonal bracing members and the horizontal frames. Of course, it will be understood that angles which are rolled to 60 degrees instead of 90 degrees may be employed, if desired.

The foundation portion of the structure may consist of three diagonal members 14-, which are connected at their upper ends to the base section of the tower at points adjacent the three vertices of the base triangular frame (5 by means of connecting

angles

15 and 16, and have their lower ends converge to substantially apoint and connected to a short channel section 17. This foundation portion of the structure will usually be embedded in concrete which will preferably extend slightly above the base triangular frame 6.

An important advantage of the present invention is that it provides a tower which is more economical to manufacture than the four sided tower. For example, atower such as illustrated in the drawings may be conveniently constructed from lift -seven pieces, while the corresponding four sided tower requires siXty-four pieces. The tower illustrated may be constructed to have a total weight of 1030 pounds, while the four sided tower will have a weight of 1130 pounds to secure the same strength for like conditions of strain. These are important considerations, in view of the fact that transmission towers are very frequently erected in places that are accessible only with difficulty, so that the weight and the number of pieces that have to be conveyed are important factors affecting the total cost of construction of the line.

Another important advantage arising from the invention is due to the construction of the foundation portion of the tower. By bringing the longitudionally extending members to a common point, and securing them at such point, it is not necessary to rely upon the concrete to secure strength for the steel structure, but it is only necessary to rely upon it to hold the pieces of the foundation structure firmly. Moreover, as already pointed out, there is also a saving in the amount of excavation and in the amount of concrete required to anchor the structure over that required to carry down the four corner posts of the usual four sided tower construction.

1 claim:

1. In a structural metal tower having but two uprights, means connecting the uprights, horizontally projecting structural elements at spaced intervals in the uprights, and upwardly extending and downwardly extending diagonals connecting the outer portions of the horizontal elements with the uprights, substantially as described.

A structural metal tower having but two spaced apart interconnected uprights forming the main skeleton of the tower, horizontally disposed elements projecting out from the main skeleton at difierent elevations, a pair of upwardly divergent diagonals connecting the outer portion of some of the horizontal elements with the respective upri hts, and downwardly divergent elements connecting the outer portion of some of the horizontal elements with the respective uprights, substantially as described.

8. A structural metal tower having but two spaced apart interconnected uprights forming the main skeleton of the tower, horizontally disposed elements projecting out from the main skeleton at different elevations, a pair of upwardly divergent diagonals connecting the outer portion of some of the horizontal elements with the respective uprights, and downwardly divergent elements connecting the outer portion of some of the horizontal elements with the respective uprights, said downwardly divergent diagonals from one of the horizontal elements crossing the upwardly divergent diagonals from a lower horizontal element, substantially as described.

l. A structural metal tower having but two spaced apart interconnected uprights forming the main skeleton of the tower, horizontally disposed elements projecting out from the main skeleton at different elevations, a pair of upwardly divergent diagonals connecting the outer portion of some of the horizontal elements with the respective uprights, and downwardly divergent elements connecting the outer portion of some of the horizontal elements with the respective uprights, said downwardly divergent diagonals from one of the horizontal eleinents terminating at Substantially the plane of the horizontal element immediately below it and wherein the upwardly divergent diagonals terminate at substantially the plane of the horizontal element next above it, substantially as described.

5. A structural metal tower including only two spaced apart uprights, means connecting the uprights, triangular horizontal frames secured to the uprights at suitable points therealong, diagonal braces extending upwardly from the outer ends of some of the triangular frames to each of the uprights, and diagonals extending downwardly on the outer ends of some of the triangular frames to each of the upri hts, substantially as described.

6. A structural tower including only two spaced apart uprights, a plurality of triangular frames secured to the uprights at suitable intervals, the lowermost of said frames being at the lowermost ends of the uprights, a downwardly extending structural member secured to each corner of the lowermost frame, said downwardly extending structural elements being convergent, an anchor member to which the lowermost ends of said downwardly extending structural members are connected, a diago-' nal extending from one corner of said lowermost triangular frame upwardly to each of the uprights, and diagonals connecting the other triangular frames with the uprights, substantially as described.

In testimony whereof I have hereunto set my hand.

FRANKLIN M. BOWMAN.