US3116838A

US3116838A - Cableway for bridge construction

Info

Publication number: US3116838A
Application number: US220592A
Authority: US
Inventors: John A Park; Robert P Fox
Original assignee: American Hoist and Derrick Co
Current assignee: American Hoist and Derrick Co
Priority date: 1962-08-28
Filing date: 1962-08-28
Publication date: 1964-01-07
Anticipated expiration: 1981-01-07

Description

1964 .LA. PARK ETAL CABLEWAY FOR BRIDGE CONSTRUCTION Filed Aug. 28, 1962 5 Sheets-Sheet 1 b ///M//HV 1 r wv m3 R INVENTORS J/nv 19. Park By Pose-27' 7? Fox MW...

Jan. 7, 1964 J. A. PARK ETAL CABLEWAY FOR BRIDGE CONSTRUCTION 5 SheetsSheet 2 Filed Aug. 28, 1962 INVENTORS J20 4. PJRK BY P7' 7-? Fox MWms m 5 Sheets-Sheet 3 J. A. PARK ETAL fram/ar Jan. 7, 1964 CABLEWAY FOR BRIDGE CONSTRUCTION Filed Aug. 28, 1962 J. A. PARK ETAL 3, ,838

CABLEWAY FOR BRIDGE CONSTRUCTION 5 Sheets-Sheet 4 Arm/giver:

Jan. 7, 1964 Filed Aug. 28, 1962 0 P m mm n a MA 72 2 l 2 3 M N l I #R W1 a M o lo 9 1K I I] 2 4, 78 H 7 U 2 H I 1 4 n 8 .V z: m 2G1 H z I "-1" y 7 w mm I I #1 a \w u 2 I a 9 I L A m a n E 1| LW| H.. o I QU w 0 O m 2 l\ O o o 1 FIE! lU United States Patent 3,116,838 CABLEWAY FOR BRIDGE CONSTRUCTION John A. Park, P.0. Box 1532, Pueblo, 0010., and Robert P. Fox, St. Paul, Minn.; said Fox assignor to American Hoist & Derrick Company, St. Paul, Minn, a corporation of Delaware Filed Aug. 28, 1962, Ser. No. 220,592 13 Claims. (Cl. 21294) The present invention relates to cableways and more particularly to a cableway which may be used in the construction of bridges, dams or other structures across deep canyons or in normally inaccessible places.

Normally in bridge construction across canyons or deep gulleys particularly, the bridge piers are built and the girders for the bridge are placed on top of the piers from the ground surface. A great amount of false frame work has to be built to support the girders as well as the piers during the bridge building operation. Cable- Ways eliminate this falsework, and permit fast construction work in rough terrain.

The device of the present invent-ion presents a cableway which is mounted to two towers, placed on opposite sides of a canyon. The trolley for carrying the work or load hook is mounted on a two-part track cable as shown, so that very high loads can be carried with the trolley. In addition the towers are pivotally mounted about two axes, about a first axis so that the tower may be raised into working position and about a second axis for moving the top of the tower from side to side sufiiciently far so that girders for opposite sides of a road bed can be put into place without changing the position of the towers. The amount the towers tilt can be changed to meet any requirement.

The unique two part track cable permits extremely high loads to be carried and thus facilitates the bridge construction by lowering cost and speeding up the overall operation.

Carriers are provided for the trolley control lines to support the slack portions as the trolley moves from side to side between the towers. Also, a unique construction of the tower is utilized for placing the track cables over sheaves at the top of the tower.

All of the cables can be a standard length as takeup reels are provided for storage of excess cable beyond any dead end points of the device.

It is an object of the present invention to present a new and improved cableway construction for building bridges dams and other structures in normally inaccessible areas.

in the drawings,

FIG. 1 is a schematic side elevational view of a cableway made according to the present invention;

FIG. 2 is a schematic end elevational View of a tower used in the device of FIG. 1;

FIG. 3 is a schematic view taken as on line 3-3 in H6. 2;

FIG. 4 is an enlarged side elevational view of a cableway tower used in the device made according to the present invention;

FIG. 5 is an enlarged end elevational view of upper sheaves on the cable tower of FIG. 4;

FIG. 6 is a fragmentary enlarged side elevational view of lower supports on a trolley used in the device of the present invention;

FTG. 7 is a fragmentary enlarged side elevational view of a latch mechanism used to engage and move a trolley control line carrier in the present invention;

FlG. 8 is an enlarged fragmentary perspective View of a base of a tower used in the device of the present invention;

3,116,838 Patented Jan. 7, 1964 FIG. 9 is a top plan view of a cable winch used for operating the trolley of the present invention;

FIG. 10 is a perspective end view of the device of FIG. 9;

FIG. 11 is a fragmentary enlarged schematic view of the trolley and rope carriers;

FIG. 12 is a schematic view of mechanism used to erect the towers; and

FIG. 13 is a schematic view of a modified form of backstay and track cable anchoring mechanism.

Referring to the drawings and the numerals of reference thereon, a cableway illustrated generally at 19 includes a first end tower 2t} and a second end tower 21, each of which is pivotally mounted about two separate axes, as shown in FIG. 8, on

pins

22 and 23, to a base 24 which is very firmly anchored into the ground surface illustrated at 25. The towers are suitably anchored to the ground surface 25 with

backstays

26, 26 which are anchored to the ground as at 27. As shown schematically in FIG. 1, one backstay is used. However, in actual operation, a plurality of backstays can be used if necessary.

A trolley or trolley car 30 is illustrated schematically in FIGS. 1 and 4 and fragmentarily in FIG. 6. The construction of the trolley will be more fully explained later. The trolley is carried on a plurality of sheaves shown generally at 31, which engage two

track cable lengths

29 and 32, which are part of one long track cable 33. The track cable not in use is wound onto a storage drum illustrated schematically at 34. One length 01f the track cable passes through a first line clamp 35 which is firmly anchored into the ground 25 and then extends upwardly at an angle over a first track cable sheave 36 which is rotatably mounted with respect to first tower 29. The lower cable length 32 extends between the towers above the work site and is mounted over a second trolley cable sheave 37 on sec/0nd tower 21. The track cable then extends downwardly to a third track cable sheave or tail block 40 which is rotatably mounted as at 41 to a support 42 which is firmly anchored into the ground. The track cable 33 is then extended upwardly over a fourth track cable sheave 43 which is rotatably mounted with respect to the second tower 21. and cable length 29 extends back to the first tower 21) above and substantially parallel to the lower length 32 of the cable.

The cable is then mounted over a fifth track cable sheave 44 which in turn is rotatably mounted with respect to first tower 28. The cable then extends downwardly back to the ground as at 4-5 and is anchored to a line clamp 46 which in turn is firmly anchored to the ground.

The excess cable is then stored on storage reel 34.

It can be seen that the two lengths of track line 33 are connected together through sheave 40 so that any load on one of the lengths extending between the towers will be transmitted through the sheave 40 to the other part of the line. Thus the load is always equalized between the cable lengths and a great deal more load can be lifted by the trolley than with a single part line.

A button line 5t) is used to support

rope carriers

60 and 61. The button line is dead ended to ground to a suitable clamp 51 and extends upwardly in a length 52 over a first button line sheave 53 and has a horizontal length 54 which extends between first and second towers 249 and 2.1 and is substantially parallel to the

lengths

29 and 32 of the track cable. The button line 50 further is threaded over a second button line sheave 55 which is rotatably mounted on second tower 21 and a length 56 of the button extends back down to a clamp 57 which is anchored in the ground 25.

The button line is used to support first and

second rope carriers

60 and 61 respectively. Rope carrier stops 62 and 63 are provided on the button line and prevent the rope carriers from moving toward the center of the cable assembly past their stops. The

rope carriers

60 and 61 are further supported on a plurality of

sheaves

64 and 65, respectively, which ride on upper length 29 of the track cable. The rope carriers are utilized to support the trolley control cables.

These supports and the trolley controls will be more fully explained later.

In addition, a messenger line 68 is provided. The messenger line is threaded over a first sheave 69 on first tower 20 and a second sheave 70 on second tower 21. The messenger line extends downwardly as shown as 71 and 72 and is dead ended at the base of the towers. The messenger line carries an electric cable for supplying power to power drums on the remote side of the cable length. A remote side, as shown in FIG. 1, is indicated at 73. The control and work side is indicated at 74.

The trolley or trolley car 30 is constructed, as perhaps best shown in FIG. 6, with a frame 79 which consists of a pair of spaced upright

first end members

80 and 81 respectively and a second pair of spaced

upright end members

82 and 83 respectively. The first and second upright end members are joined together at the bottom thereof by a pair of spaced parallel

lower frame members

84 and 85 and also are joined together by crossed braces illustrated generally at 86.

A first upper sheave carrier 89 is pivotally mounted as at 90 between the first

upright end members

80 and 81. The sheave carrier 89 has a pair of spaced apart sheaves 91 and 92 rotatably mounted thereon. The sheaves 91 and 92 engage upper length 29 of the track cable.

A second upper sheave carrier 95 is pivotally mounted as at 96 between second

upright end members

82 and 83. The second upper sheave carrier has

sheaves

97 and 98 rotatably mounted thereon.

Sheaves

97 and 98 also engage upper length 29 of the track cable.

A first lower sheave carrier 99 is pivotally mounted as at 100 between the first

upright end members

80 and 81 of the trolley and sheaves 101 and 102 are rotatably mounted thereto. A second lower sheave carrier 103 is pivotally mounted as at 104 between the second

upright end members

82 and 83 of the trolley and this sheave carrier has

sheaves

105 and 106 rotatably mounted thereto.

Sheaves

101 and 102 and 105 and 106 engage lower length 32 of the track cable and the load on the trolley 30 is then supported through the

sheaves

91, 92, 97, 98, 101, 102, 105 and 106.

Three load hook sheaves 109, 110 and 111 are rotatably mounted between

lower frame members

84 and 85, respectively as 112, 113 and 114, respectively. In addition, a small guide sheave 115 is rotatably mounted between two center support members 116 and 117.

As shown in FIG. 6, first rope carrier 60 is constructed with two spaced,

upper side members

119 and 120. The two

rope carriers

60 and 61 are substantially the same in construction except one operates to the left and one to the right.

A button line sheave 122 is rotatably mounted between the

side members

120 and 119 and is supported on the horizontal length 54 of the button line 50 which extends between the two end towers.

The plurality of sheaves 64 are rotatably mounted between sheave side plates 123 and are supported by and rotate on upper length 29 of track cable 33. A lower rope carrier sheave 121 prevents the carrier from jumping off its supporting cables.

A bumper support 124 is fixedly attached between

side members

119 and 120 and extends toward the trolley 30. A bumper 125 is fixedly attached to an outer end thereof. A bumper 126 is attached to the side plates 123.

The sheave carriers on the trolley also have

bumpers

127 and 128 which are alined with the bumpers on the rope carriers. When the trolley moves into engagement with the rope carriers the bumpers take the initial shock of contact. In addition, a trolley return line sheave 130 is rotatably mounted between the

side support members

119 and 120, a trolley line guide sheave 131 and a trolley control line guide sheave 132 are also rotatably mounted between the side members.

A pair of latch assemblies illustrated generally at 135 are provided at the upper ends of the pairs of upright side support members of the trolley. The latch assemblies are utilized for engaging the respective alined and adjoining rope carriers and moving the rope carriers with the trolley as the trolley goes back and forth between the towers. The latch assemblies will permit the rope carriers to be returned against the

stops

62 and 63, respectively, when the trolley is returned toward the center of the cable support from position adjacent either tower.

The latch assembly consists of a latch dog 136 which is pivotally mounted as at 134 to the upper ends of the

upright support members

80 and 81 and 82 and 83 respectively. The latch dogs 136 extend outwardly in a direction parallel to the track cables beyond the bumpers on the trolley.

As can be seen the outwardly extending ends 137 of each of the latch dogs has a tapered ramp 138 and a cam receptacle 139 which is positioned to engage a roller 140 that in turn is rotatably mounted on a support 141 which is fixedly attached to sheave side plate 123. The roller 149 is rotatably mounted with respect to the rope carriers. As stated previously each of the rope carriers is substantially identical in construction and there is a roller 140 which will be engaged by the opposite latch member on the trolley as the trolley moves toward opposite towers from center.

As can be seen best in FIG. 7 the latch dog 136 is guided with upright guide members 145 which are fixedly attached to a bracket 146 which in turn is fixed to the upper sheave carriers on the trolley. A rod 147 is slidably mounted with respect to bracket 146 and a spring 148 is positioned beneath the bracket and around the rod 147. A clevis 149 is attached to the rod 147 and also is attached to an ear 150 on the latch dog 136. A washer 151 is positioned over rod 147 and abuts on lower end of the spring. A pair of nuts 152 are threadably mounted on the rod and are used to adjust tension on the spring 148.

The spring 148 exerts a resilient force downwardly in the direction as indicated in arrow 155 in FIG. 7 and thus insures that the cam receptacle 139 will be nested on the roller 140 when they engage. The spring 149 will yield to permit the latch dog 136 to pivot upwardly as the roller engages and moves along surface 138.

As can be seen, when the trolley moves in the direction as indicated by arrow 156 in FIG. 1, and with the rope carrier against stop 62 on button line 50, as the trolley 30 approaches the rope carrier 60 the outer end 137 of latch dog 136 will engage roller 140 and the roller moves along surface 138. This will lift the latch member up over the roller and when the cam receptacle 139 has traveled far enough it will snap over and lock onto roller 140. The bumpers 125 and 126 of the rope carrier and the

bumpers

127 and 128 on the trolley will collide and the trolley will push the rope carrier along.

When the trolley is moved in an opposite direction from arrow 156, the cam 139 will engage roller 140 and the rope carrier 60 will be pulled along with the trolley until it engages stop 62. The latch dog 136 will move upwardly in direction opposite from that shown by arrow 155 and the rope carrier will be released. The same action will occur when the trolley moves against the second rope carrier 61.

It should be noted that button line is the same length as the working lengths of the track cable. Thus thermal expansion and working strains of the two cables will be identical and the button line will not become too loose or too slack for the rope carriers to function.

The trolley is moved through the utilization of a trolley control cable or line 160. The trolley control cable 160 is controlled with a traction drum 195 illustrated in FIG. 9. As shown there the trolley control cable 160 is endless and wound about the drum 159. As shown schematically in FIG. 1, a first length 161 leading from the drum eX- tends under a guide sheave 162 rotatably mounted in a sheave block 163 (FIG. 8), which is attached to the base 24 of the tower on the work side 74 of the cableway. The in haul portion of the trolley cable then has an upwardly extending length 164 and is mounted on a second trolley control sheave 165 which is rotatably mounted with respect to first tower 20. The trolley cable has a second length 166 which extends toward the trolley and is mounted over a trolley sheave 167 which is rotatably mounted with respect to the trolley as at 163. The trolley cable then has a third length 171 extending back over tower 20 where it is mounted over a sheave 172, which is rotatably mounted with respect to the tower 21). A downwardly extending length 173 is then mounted over a sheave 174 which in turn is rotatably mounted in a sheave block at the base of the tower 20. The in haul part of the trolley control cable is then dead ended as shown at 175. Excess cable is wound on a storage reel 176.

The return portion of the trolley cable extends from the traction or control drum 159 and has a first length 189 which extends to a first return sheave 181 mounted in a sheave block 132 and has a second return length 133 extending upwardly to be threaded over a sheave 184 rotatably mounted on tower 2h. The return portion of the trolley control cable then has a third horizontal length 185 which is threaded underneath sheave 130 on first rope carrier 61) and is then threaded over sheave 115 on trolley 30 and is then threaded over sheave 1313 of second rope carrier 61. V

The return portion cable 160 is then mounted over a sheave 186 which is rotatably mounted with respect to tower 21. A fourth horizontal length 1 37 of the return portion of the control cable then extends back to trolley 30 and is mounted over a sheave 188 which is rotatably mounted as at 189 to an opposite end of trolley 30 from sheave 167. A fifth length 190 of the trolley return cable then extends back to tower 21 and is dead ended on the tower.

Thus it can be seen that by operating drum 159 the trolley will be moved between the towers in one direction or the other. Because the cable is endless there is no need for any takeup drums on either side of the cable as what is paid out from one side of the drum is automatically taken up by the other. This makes a very smooth operation of the trolley. The drum construction will be more fully explained later.

A load line 195 is mounted over and driven from a load drum 196 and is further mounted over a sheave 197. The load line has an upwardly extending length 198 which in turn is mounted over a second sheave 199 which is rotatably mounted on tower 20. The load line then extends horizontally underneath roller or sheave 131 on first rope carrier 60 and is rotatably mounted over sheave 109 on the trolley. The load line has a load lifting portion 2% extending downwardly from sheave 109 which in turn is mounted over a sheave 201 that is rotatably mounted onto a load spreader block or hoist hook assembly 202. The hook assembly also has a second sheave 203 rotatably mounted thereon and the line is mounted underneath the sheave. An upwardly extending portion 204 is then mounted over sheave 111 on carrier 30 and the load line then extends to a sheave 207 which is rotatably mounted on second tower 21. The line further extends downwardly to be mounted over a sheave 26-3 which is rotatably mounted with respect to the ground 6 and is dead ended as at 209 on the ground. A storage reel 210 is provided for taking up any excess line.

If desired the load line can be reeved as shown in dotted lines in FIGS. 1 and 11, so that two additional working

parts

211, 211 will be effective in raising the load. In doing this the load line is threaded from sheave 210 upwardly over sheave on carrier 30 and then downwardly. It is then mounted on sheave 203. This increases the lifting capacity of the cable used for the load hook 2112. The load line runs through its sheaves as the trolley moves. The load hook can be raised or lowered simultaneously with movement of the trolley.

In FIG. 2 is mechanism utilized for moving each of the towers 2t} and 21 from side to side. As can be seen the tower is pivoted with respect to the base 24 about axis pin 22.

As shown by way of example, the top of the tower supporting the track cable 33 can be tilted 20 feet to the left or right of center. The positions of the tower are shown in dotted lines in FIG. 2. Beams carried by the load hook may be placed 40 feet apart on the bridge piers. A complete road can then be constructed using only the cableway.

A pair of side

guy wire assemblies

215 and 216 are attached to the top of the tower as at 217 and extend backwardly down to the ground. Guy wire 215 is attached to the ground as at 218 and the guy wire 216 is attached to the ground as at 219. The guy wires are securely anchored into the ground 25.

Each of the guy wires has an upper portion 212 and a lower portion 213 and suitable adjustable tackle indicated generally at 226 extending between the upper and lower portions. As shown in FIG. 3 and FIG. 2 a set of lower sheaves 221 is attached to each of the lower portions 213 and a set of upper sheaves 222 is attached to each of the upper portions 212 of the guy wires. In each of the tackle assemblies, as shown, a cable 225 is dead ended as at 226 to a lower sheave block located in guy wire 216 and then threaded alternately over sheaves of the upper and lower sheave assemblies and then has a length 227 extending downwardly. The cable extends over a winch drum 228 which is powered with a motor 229. The cable extends horizontally as at 231 under a sheave 23 1 which is fixedly attached to a bracket 232 which is fixed to the ground. The cable has an upwardly extending length 235 which extends upwardly to a first sheave of the upper sheave assembly 222 in guy Wire 2115 and then is threaded between the upper and lower sheaves as before and is dead ended to a lower sheave assembly 221 of guy wire 215.

As can be seen the cable 225 is continuous and in order to tilt the tower in either direction the drum 22 8 is activated which will shorten the center distances between the upper and lower sheave assemblies in one guy wire and will lengthen the center distances between the upper and lower sheaves of the opposite guy wire.

It can be seen that the tilting of the tower from side to side is accurately controlled and the tower is firmly held at all times during this operation. The tower will continue to support the necessary cables during this moving operation.

In FIGS. 4 and 5 there is shown structure utilized in placing the track cables for the trolley into place at the top of the tower as well as other cables that are necessary for operation of the unit. As can be seen the

sheaves

44 and 36, which are used to support the track cable at tower 20 are rotatably mounted on sheave pins 241) and 241 respectively which in turn are held on suitable support members 242 of the tower.

The sheaves can be removed from their provided slot 243 defined by the

support members

242, 242.

A lifting jib 244 is provided at the very top of the tower. The jib supports a pair of

jib sheaves

245 and 246 which are rotatably mounted to the lifting jib at the outer ends thereof. The jib sheaves 245 and 246 are spaced an equal distance from the center of the tower. The lifting jib 24-4 is rotatably supported with suitable members 247 extending upwardly from

support members

242, 242. The jib 244 is rotatably mounted about a vertical axis. A cable 250 is mounted on a winch drum 255 which is driven by a motor 256 and extends upwardly in a length 254 and is then threaded over jib sheave 246 and extends across the top of the jib and over sheave 245. The cable has a length 252 extending downwardly. A lifting hook 253 is attached to the end of the cable. The winch and lifting jib are used for hoisting the track cable 33 into place over the sheaves on the towers. As can be seen the cable 33 is hoisted upwardly. The upper sheave 44 is removed from the tower by pulling pin 240. The track cable 33 is then slipped through an opening 266* which is open to slot 243 by rotating the jib until the track cable is properly positioned and is then placed over the lower sheave 36. The second cable length is placed in position the same way after the sheave 44 has been replaced so it is rotatably mounted on pin 240. The lifting hook raises the cable upwardly and the cable is slipped through opening 260. A platform 261 is provided adjacent the upper portions of the tower for people to stand on to help move the cable in place.

As can be seen the jib extends outwardly from the sides of the tower an equal distance and thus the loads on the top portions of the tower are equalized. No bending moment is introduced into the lifting operation. The upper portions of the tower, of course, are highly susceptible to bending loads and damage to the tower could result from any heavy bending loads. By having an equalized load the upper portions of the tower can be much lighter than if a cantilevered jib was used. Rotating the jib about its axis makes it easy for the track cable to be installed through opening 260 onto the track cable sheaves.

Thus through the use of this type of assembly the installation of the track cable is greatly simplified and the upper portions of the tower do not have to be specially reinforced.

Referring to FIG. 9 the driving winch assembly for the trolley control cable is shown. An electric motor 263 is mounted on a winch base 264 which can be permanently mounted to asupport such as a floor of a semitrailer positioned on the work side of the cableway. The motor drives through a suitable drive arrangement 265 to a jack shaft 266 which in turn is drivably connected to a drive arrangement 267 which drives a drum shaft 268. The trolley control drum 159 is drivably mounted on the drum shaft 268. The trolley control cable 160 is mounted over provided grooves in the drum. As shown the first length 161 of the trolley control cable 160 is placed in a first groove 271 of the drum. Also as shown in FIGS. 9 and 10 an idler sheave 272 having a plurality of grooves is mounted on a shaft 273 which in turn is rotatably mounted in suitable bearings 274 mounted to the base frame 264 of the winch.

As can perhaps best be seen in FIG. 10 the axis for the sheaves 272 is positioned at an angle with respect to the axis of drum 159.

In this position, the lower portion of a first sheave groove 275 is alined to receive a cable length coming from first groove 271 of the drum. The first sheave groove 275 then directs the cable to a second drum groove 276. A second sheave groove 277 receives 21 cable from the underside of second drum groove 276 and directs the cable to position in a third drum groove 278. The cable is then received by a third sheave groove 279 which is directed to the fourth or last drum groove 280. The opposite lengths of the trolley cable then leaves the control drum from the fourth groove 280.

By wrapping the cable around the drum several times, as shown in FIGS. 9 and 10, the load which can be moved by the drum is greatly increased. The angled sheaves insure that the cable will lead into the proper grooves on the drum at all times.

As shown schematicall in FIG. 12, when the towers 29 or 21 are to be raised, they are assembled in a horizontal position with pin 23 installed in base 24. A strut 285 is pivotally mounted as at 284 on the base also. The strut has a saddle 286 at the top thereof. Backstay 26, which is attached to upper portions of the tower is placed on saddle 286 and attached to tackle mechanism 187 operated by a winch 289. In addition, a guy wire 289 is attached between the strut 285 and the tower. The tower is then pivoted to upright position by pulling on backstay 26.

The strut increases the moment which can be placed on the tower to tend to lift it into upright position. Once the tower is in place, the backstay is anchored and the strut can be removed. When both towers are in place the cables extending between the towers can be installed.

The use of the cableway makes bridge construction very easy. The concrete for the piers can be carried to the forms in suitable containers. The operation is simple and rapid. Deep canyons present no problem.

If greater loads are to be lifted a track cable of more than two supporting lengths can be used. The tail block sheave 40 acts as a load equalizing sheave. Other load equalizing sheaves would be added if more lengths are used for support.

All power generators and the control cable drum can be mounted in a semi trailer for easy moving of the equipment.

The tilting feature of the towers permits building a road bed with the cableway without moving the tower foundations. This makes the use of cableways feasible for construction jobs.

It has been found that in very rough terrain it is not always possible to anchor the backstay of the tower along the tilting axis of the tower. If the anchor points are not on this axis as the tower tilts the track cables and backstay will tighten or loosen, depending upon the position thereof.

Where the tilting of the tower is minimal this does not become a problem. However in some construction jobs it is necessary to cover a wide area with the cableway. For example, using a 200 foot tower, the top of the tower may be tilted feet to either side of center. Any misalinernent between the anchor points and the tilting axis becomes significant.

Also in very rough terrain the anchor points may be on the side of a hill and vertically offset from the tower axis a considerable distance.

In FIG. 13 structure is shown which will compensate for the differences in length of the track cable and the backstay which are necessary to hold the towers properly positioned under these conditions.

As shown, the backstay 26 and the two lengths of track cable 33 which are normally anchored to the ground will be fastened with respect to a sheave block 291. The backstay is fastened directly thereto, as at 292. The track cable is passed through

clamps

293, 293, which are the same as the

clamps

35 and 46 used previously at the ground. The clamps are of design so that the cable is not kinked or damaged. The excess cable is stored on

storage drums

34, 34 as before.

The

clamps

293, 293 are attached to the sheave block as at 294, 294. A sheave 295 is rotatably mounted in the sheave block 291.

An adjustment cable 296 is anchored to ground 25 with a double swivel 227. The adjustment cable 297 extends over sheave 295 and an upper adjustment sheave assembly 298 is rotatably attached with respect to the other end of the cable.

A lower adjustment sheave assembly 301 is rotatably tounted in a double swivel block 362 which in turn is attached to the ground at position spaced from double swivel 297. A cable 303 is reeved between the .upper and

lower sheave assemblies

298 and 301 respectively.

An end portion 304 of cable 303 extends from the lower sheave assembly to a suitable conventional power hoist 305.

By controlling the cable 303 to lengthen or shorten the distance between the upper and lower adjustment sheave assemblies, the length of the track cable and backstay can be accurately controlled to compensate for necessary changes when the tower is tilted. .It can :be seen that the same adjustable machinery can be used for mounting the backstay and equalizing sheave for the track cable on the .remoteside of the cableway.

Because the towers can be tilted a great amount to either side, and, of course, can be positioned any desired distance apart, a large area can be covered for construction work without changing the tower positions. Regions formerly completely inaccessible now can be worked for construction of dams, bridges or other structures.

While the description herein deals mainly with a cableway for bridge construction, it is to be considered by way of example rather than limitation. It is apparent that the cableway can be adapted to many construction projects.

What is claimed is:

l. A cableway comprising a pair of spaced apart towers, a track cable suspended between said towers, a trolley mounted for movement along said track cable, cable means for moving said trolley back and forth between said towers, said cable means for moving said trolley being controllable from position adjacent a first of said towers, a load line carried by said trolley having means thereon to support a load, means adjacent a first of said towers to control said load line and thereby raise and lower a load carried by said trolley, a button line extending between and supported by said towers, at least one rope carrier supported by and movable along said button line, said rope carrier having means thereon to support said cable means for moving said trolley, said track cable being anchored at a first end thereof with respect to the ground at position spaced from said first tower, extending over a first sheave rotatably mounted on said first tower, thence extending over a sheave rotatably mounted on said second tower, thence extending over a sheave rotatably mounted with respect to, supported by and adjacent the ground, thence extending back over a fourth sheave rotatably mounted on said second tower spaced from said second sheave, thence extending over a fifth sheave rotatably mounted on said first tower, and clamp means anchored with respect to the ground adjacent the first end of said cable for receiving said cable from said fifth sheave.

2. The combination as specified in claim 1 wherein said track cable is of standard length and excess cable is stored on a storage drum rotatably mounted adjacent said clamp means.

3. The combination as specified in claim 1 wherein said trolley has sheaves mounted thereon that engage said track cable so that each of the portions of said cable extending between said towers supports an equal load.

4. A cableway comprising a pair of spaced apart towers, two lengths of track cable suspended between said towers, said track cable lengths being joined together and mounted over a rotatable load equalizing sheave, a trolley mounted for movement along said track cables and having means thereon for transferring load to both of said cable lengths, power operated continuous cable means for moving said trolley back and forth between said towers, a button line extending between said towers and fastened with respect thereto, a rope carrier mounted for movement along said button line, said trolley controlling movement of said rope carrier, means on said rope carrier for supporting said cable means, a load line carried by said trolley and extending to at least one .of said towers, said load line having means thereon to .engage and support a load, and means adjacent a first of said towers to control said load line and thereby raise and lower a'loadcarried by said trolley.

5. The combination as specified in claim 4 wherein .said button line is the same length as said track cables.

6. The combination as specified in claim 4 wherein 7. The combination as specified in claim 6 wherein said track cable lengths are vertically spaced and each length is mounted over a separate sheave at each tower, said load equalizing sheave being mounted adjacent the ground spaced from said second tower and the cable lengths being fastened with respect to the ground at position spaced from said first tower.

8. The combination as specified in claim 7 wherein said track cable, said load line and said button line are of standard length and excess cable is stored on rotatably mounted storage drums.

9. The combination as specified in claim 7 wherein a backstay is fastened to said first tower, and wherein said backstay and said cable lengths adjacent said first tower are attached to a sheave block, and adjustable means connecting said sheave block to the ground.

10. The combination as specified in claim 4 wherein two rope carriers are provided, separate spaced apart stop means on said button line for each carrier, a first of said rope carriers being movable along said button line be tween said first tower and a first of said stops, a second of said rope carriers being movable along said button line between said second tower and a second of said stops, said trolley having means thereon to engage said first carrier and move it toward said first tower as said trolley moves from center portions of said cable toward said first tower and to move said first rope carrier against said first stop as said trolley returns to center, said trolley also having means to move said second rope carrier toward said second tower and to return said carrier to position against said second stop responsive to movement of said trolley.

11. The combination as specified in claim 10 and a separate jib rotatably mounted on each tower about an axis substantially coincident with the longitudinal axis of its respective tower, a separate pair of jib sheaves rotatably mounted on each of said jibs, the jib sheave of each pair being equally spaced from the axis of their respective tower, and a separate hoist cable reeved on each pair of said jib sheaves so that a load lifted by said hoist cable results in equal load on each of the sheaves in a pair.

12. A cableway comprising a pair of spaced apart towers each pivotally mounted at the base thereof about an axis substantially parallel to a line extending between said towers, a track cable suspended between said towers having at least two lengths vertically spaced apart and joined at one end by load equalizing means, a trolley mounted for movement along said track cable lengths and having support means engaging both of said track cable lengths, a powered cable control drum, cable means on said drum and reeved to said trolley for moving said trolley back and forth between said towers, said cable means for moving said trolley being endless and reeved on said drum so that as cable is payed out from one side of the drum the slack is taken up by the other side of the drum, and a load line controlled by a winch drum and mounted on a sheave on a first of said towers, extending to said trolley and being looped downwardly to engage and support a sheave on a load hook and extending from said trolley to be dead ended with respect to a second of said towers.

13. A cableway comprising apair of spaced apart towers, a track cable suspended between said towers and having at least two lengths vertically spaced apart and joined at one end by load equalizing means, a trolley mounted for movement along said track cables and having means thereon for transferring load to both of said cable lengths, power operated continuous cable means for moving said trolley back and forth between said towers, a button line extending between said towers and fastened with respect thereto, a rope carrier mounted for movement along said button line, said trolley controlling movement of said rope carrier, means on said rope carrier for supporting said cable means, a load line carried by said trolley and extending to at least one of said towers, said load line having means thereon to engage and sup- References Cited in the file of this patent UNITED STATES PATENTS 1,086,912 Hadsel Feb. 10, 1914 2,318,218 Grabinski May 4, 1943 10 2,790,622 Priest Apr. 30, 1957 FOREIGN PATENTS 843,620v Great Britain Aug. 4, 1960

Claims

1. A CABLEWAY COMPRISING A PAIR OF SPACED APART TOWERS, A TRACK CABLE SUSPENDED BETWEEN SAID TOWERS, A TROLLEY MOUNTED FOR MOVEMENT ALONG SAID TRACK CABLE, CABLE MEANS FOR MOVING SAID TROLLEY BACK AND FORTH BETWEEN SAID TOWERS, SAID CABLE MEANS FOR MOVING SAID TROLLEY BEING CONTROLLABLE FROM POSITION ADJACENT A FIRST OF SAID TOWERS, A LOAD LINE CARRIED BY SAID TROLLEY HAVING MEANS THEREON TO SUPPORT A LOAD, MEANS ADJACENT A FIRST OF SAID TOWERS TO CONTROL SAID LOAD LINE AND THEREBY RAISE AND LOWER A LOAD CARRIED BY SAID TROLLEY, A BUTTON LINE EXTENDING BETWEEN AND SUPPORTED BY SAID TOWERS, AT LEAST ONE ROPE CARRIER SUPPORTED BY AND MOVABLE ALONG SAID BUTTON LINE, SAID ROPE CARRIER HAVING MEANS THEREON TO SUPPORT SAID CABLE MEANS FOR MOVING SAID TROLLEY, SAID TRACK CABLE BEING ANCHORED AT A FIRST END THEREOF WITH