US 2835345 A
Description (OCR text may contain errors)
May 20, 1958 w. BECK 2,835,345
ELEVATOR Filed Sept 14 1954 3 Sheets-Sheet 1 49 K i" 1 ML 1. x4 I J] IIHIII 3 3 W. BECK ELEVATOR May 20, 1958 5 Sheets-Sheet 2 Filed Sept. 14, 1954 a MW M E CHAN/SM WEIGH 71E D FLA TFORM M y 1958 w. BECK 2,835,345
ELEVATOR Filed Sept. 14, 1954 5 Sheets-Sheet 3 GUIDES 27L o o near/x1; PLATFORM CAR LIGHTS 2 53 ELEVATOR Walter Beck, Rock Island, 11]., assignor, by mesne assignments, to Montgomery Elevator Company, a corporation of Delaware Application September 14, 1954, Serial No. 455,876
7 Claims. (Cl. 187---17) This invention relates to an elevator mechanism for installation in locations where it is impractical to mount the operating machinery for the elevator at the top of the shaft. It is particularly. adapted for use in television or radio broadcast towers, although it may also be employed where similar problems are encountered.
The extreme normal range of a television transmitter is determined by the height of the tower from which the signals are beamed, and for this reason in hilly country a television broadcast tower will ordinarily be located on a convenient ridge so as to increase the range of the station, and the same result is achieved in the big cities by locating the television antennae on the top of tall buildings.
In flat country where there are no skyscrapers upon which television antennae may be mounted the range of a station can be increased only by building an extremely high broadcast tower. Consequently, in the plains states television broadcast towers which are several hundred feet in height are coming into use; and there are towers planned for parts of the southwest which are expected to be anywhere from a thousand to fifteen hundred feet high. This makes an elevator absolutely essential to the maintenance of the upper parts of the tower, and work on the aircraft warning signal lights which are es sential on all such structures.
The construction of television towers is such that no conventional elevator mechanism can practically be in stalled in such a tower; because the motor and drive pulley are at the top of the shaftway, and the cables from which the elevator cage is suspended hang in a large loop from the drive pulley with the cage on one side of the loop and a counterweight on the opposite side so that there is approximately even weight on the two sides and the elevator motor may drive the elevator cage in either direction with equal ease. The counterweight is essential to provide balanced thrust in both directions on the drive pulley. This puts a very heavy load at the top of the shaftway, and makes it necessary to do the majority of maintenance work at the top of the shaftway. No such arrangement could be employed in a broadcast tower which is several hundred feet high because the towers are very slender and are supported by guy cables, and mounting of the heavy elevator drive. mechanism at the top of the tower would throw a tremendous strain upon the cables as well as the entire tower structure. Furthermore, the top of the tower is ordinarily quite open, and a housing for the drive mechanism would add further undesirable weight. Likewise, the space is very restricted, and service work would be very difiicult.
In accordance with the present invention an idler pulley is placed at the top of the shaftway, and the elevator drive pulley and motor are mounted upon a platform which is suspended from the bottom of the elevator cable, the cage being mounted at the two ends of the cable so that it may run up and down between the sus- United States Patent 2,835.3 Patented May 2t), 1938 pended, machinery weighted platform and the idler pulley at the top of the shaftway. The weighted platform suspended at the bottom of the cable provides ample friction between the drive pulley and the cable to obtain it a positive drive without slippage, so that a counterweight may be eliminated. The elevator shaftway may be provided with conventional vertical guide rails which permit the elevator cage to have all normal safety devices, and the weighted platform may be mounted to ride up and down a short distance between the lower ends of the guide rails to eliminate any problems arising from cable stretch or changes in cable length and tower height due to temperature variations. The variations in cable length and tower height due to temperature changes in a climate such as that found in the southwest of the United States may be eight or nine inches per thousand feet of height.
Ordinarily the maintenance work necessary on a television broadcast tower can be performed by one man, or at the most, two; so the elevator cage may be made quite small and light. A cage having a three foot square platform is ample, and by using principally aluminum construction the total weight of the cage need be only five or six hundred pounds. Adequate friction on the elevator cable may be maintained by a machinery platform having a total weight of about forty-eight hundred between guide rollers which may conveniently be mounted on the elevator cage itself to hold the cable away from the cage. Likewise, conventional elevator mechanisms have a flexible control cable which connects the control panel in the elevator cage electrically with the controls for the elevator drive mechanism. Ordinarily the control cable is not under tension, so that it is particularly susceptible to wind deflection. In particular, the governor rope which normally hangs loose below the elevator cage could very easily be blown out of the shaftway and caught in the tower framework. Thus,
make them substantially immovable.
the governor rope is also held in place by suitable rollers; and the control cable is replaced by a series of parallel trolley wires extending the length of the shaftway which may be supported at as close intervals as is necessary to Electrical communication between the control panel in the cage and the trolley wires is provided by conventional trolley shoes or rollers on the side of the cage.
The invention is illustrated in a preferred embodiment in the accompanying drawings in which:
Fig. 1 is an elevational view of a broadcast tower provided with elevator mechanism constructed in accordance with the present invention;
Fig. 2 is a view similar to Fig. l, drawn to a larger scale, with the center portion of the tower broken away;
Fig. 3 is a section 011 an enlarged scale taken as indicated along the line 33 of Fig. 1;
Fig. 4 is a section on an enlarged scale taken as indi cated along the line 4-4 of Fig. 1;
Fig. 5 is a schematic view of an elevator mechanism constructed in accordance with the present invention;
Fig. 6 is a schematic view of a normal high rise elevator mechanism;
Fig. 7 is a fragmentary elevational view of the upward travel limit control trolley wire and associated trolley; and
Fig. 8 is a control circuit diagram.
Referring to the drawings in greater detail, and referring first to Figs. 1 and 2, a television broadcast tower it) is shown as consisting of the customary open girder construction, As seen in Figs. 3 and 4-, suitable cross. members it are provided at intervals within the broad cast tower framework in alignment with horizontal frame members l2 to receive brackets 13 for longitudinal mounting plates 14 on which are mounted the guide rails 15 of the elevator shaftway. As best seen in Figs. 1 and 2, the mounting plates 14 and guide rails 15 ex tend at their lower ends into a closed housing 16 at the bottom of the shaftway.
At the top of the tower is a pair of parallel girders l? which, as seen in Fig. 3, support pillow blocks 18 for a grooved idler pulley it? which is journalled in the pillow blocks. An elevator cable it is trained over the idler pulley l9 and has its ends secured to an elevator cage, indicated generally at 21, so that movement of the cable 20 over the pulley 19 may raise or lower the cage.
As seen in Figs. 2 and 4, platform 22 in the housing 16 has a base 23 on which is mounted an electric elevator motor 24 and gear case 25 having a grooved drive pulley as one end of the shaft for which is supported in a bearing block 2'7. The elevator cable 2:3 passes around the grooved drive pulley 26 so that the platform 22 is suspended from the cable. The platform: has recesses 28 provided with guide shoes 29 to receive the guide rails 15, so that the platform 22 may ride up and down in the housing 16 to compensate for tower stretch or shinkage and cable stretch or shrinkage With temperature changes, and yet the platform is guided against lateral shitting. The total weight of the platform 22 and mechanism supported thereon is sullicient to provide the necessary frictional engagement between the elevator cable 2d and the drive pulley 26; and if the normal weight of the platform and machinery is insufilcient, additional weights may be added as needed. The idler pulley 19 and drive pulley 26 are shown as single should also be mounted between guide rollers similar to the guide rollers 37.
Control of the elevator may be accomplished by conventional controls which are illustrated diagrammatically .in Fig. 8. in ordinary elevator construction the cable which connects a control panel in the elevator car with the elevator control mechanism at the motor hangs free in a large loop below the elevator cage, and extends upwardly along the side of the shaftway to the control panel adjacent the driving mechanism upon which are mounted the various relays and switches of the control system. Any loose cable of the above described character would be completely impractical in an open shaftway .such as that here contemplated, because the loose loo of cable could very easily be blown outside the cage .shaftway so that they may be anchored at whatever intervals are necessary to prevent them from being serious- 1y deflected by wind. A series of trolley members 37a to 42a are mounted on the elevator cage to ride respectively on the trolleys 37 to 42; and as seen in Fig. 7,
which illustrates the trolley 4 in, each of the trolleys .38 to up relay 48, down relay and t. rough trol grooved, so that the elevator cage 21 is supported by a single cable strand. cables might be used as is more common in elevator construction.
The elevator cage 21 is of generally conventional construction, in that it has a lifting beam 31 upright side beams 31, and a base beam 32 upon which the platform 33 of the cage is mounted. As best seen in Pig. 2, the ends of the cable are secured, respectively, to the lifting beam 30 and base beam 32. The platform 33 for the cage is of very small dimensionsfor example, three feet square, and the cage is constructed of lightweight metals such as aluminum so as to reduce its weight to minimum. An adequate three foot square cage having enclosed sides 34- aud a seven foot high door opening 35 may have a weight as low as six hundred to eight hundred pounds and a capacity of six hundred pounds, which is ample to carry one or two maintenance men and any equipment they would normally require for working on the upper levels of a broadcast tower. Extending rearwardly from one of the side beams 31 is a bracket 36 at the end of which is mounted a pair of guide rollers 37 between which the free side of the cable 20 is guided so that it does not slap against the cage 21 or the framework of the tower when subjected to high winds to which it is exposed due to the open shaftway construction. The elevator may also be equipped with a conventional governor (not shown) which automatically sets safety brake shoes on the elevator car 21' into frictional engagement with the guide rails 15 if the elevator exceeds a predetermined maximum safe speed. This is standard equipment and is not here shown. It is mentioned only because the governor rope (not shown) is ordinarily not under any substantial tension, and
However, it is obvious that several may conveniently consist of a parallelogram linkage 43 provided with a tension spring 43a which tends to extend the linkage so as to hold a trolley wheel 44 in firm contact with the trolley wire.
The trolley wire 37 furnishes a main control wire, which communicates through trolley 37:: with the usual safety switches on the car, such, for example, as a normally closed safety switch t5, a gate switch 4-6 and'a stop switch 57, through which the circuits pass through trolley wire ley wires 39 and ill and trolleys 39a and iller, respectively, to ""up and down push buttons and 53. Car lights 52 and 53 may be wired through a snap switch 54. The up" control circuit is completed through up trolley 411a and '--\trolley wire 41, the upper end portion 55 of which is sheathed with insulation so that if the car overruns the sheathed portion provides safety device which breaks the up circuit at the trolley ila and stops the cage. The separate down trolley wire a2 and trolley 42a permit l the cage to be started down, clearing insulated cable portion 55, when the down button 51 is pressed.
The foregoing detailed description is given for clearness of understanding only and no unnecessary limitations are to be understood therefrom, as some modifications will be obvious to those skilled in the art.
1. In an elevator mechanism: a shaftway; idler sheave means at the top of the shaftway; cable means trained over said idler sheave means; an elevator cage to which the ends of said cable means are secured; a platform separate from the elevator cage having drive sheave means around which the lower end of said cable means is trained where by said platform is suspended on said cable means; driving mechanism on the platform for driving said drive sheave means; and electric control means for controlling operation of the driving mechanism.
2. The device of claim 1 in which guide means are provided to laterally restrain the cable between the sheave means.
3. The device of claim 1 in which guide roller means on the elevator cage provide lateral restraint for the cable.
4. In an elevator mechanism: a shaftway; idler sheave means at the top of the shaftway; cable means trained over said idler sheave means; an elevator cage to which the ends of said cable means are secured; a platform having drive sheave means around which the lower end of said cable means is trained, said platform being suspended on said cable means; driving mechanism on the platform for driving said drive sheave means; and electric control means for controlling operation of the driving mechanism tacting trolley member, and a dielectric sheath surrounds the upper extremity of said limit wire to break the circuit to the trolley member and positively limit upward travel of the cage.
6. In an elevator mechanism. a shaftway having vertical guide rails; idler sheave means at the top of the shaft- Way; cable means trained over said idler sheave means; an elevator cage to which the ends of said cable means are secured, said cage having guide shoes embracing said guide rails; a platform having drive sheave means around which the lower end of said cable means is trained, said platform being suspended on said cable means and having guide shoes embracing the guide rails; driving mechanism on the platform for driving said drive sheave means; and
electric control means for controlling the operation of the driving mechanism from the cage.
7. The device of claim 6 in which safety means are provided to limit the approach of the cage toward the suspended platform.
Rcferences Cited in the file of this patent UNITED STATES PATENTS 216,568 Holske June 17, 1879 515,641 Backman Feb. 27, 1894 516,343 Blake et al Mar. 13, 1894 1,071,309 Goggin Aug. 26, 1913 2,420,903 Noble May 20, 1947 FOREIGN PATENTS 112,293 France May 19, 1876 13,500 Great Britain Nov. 9, 1888