US 3344452 A
Description (OCR text may contain errors)
P. J. QUIMBY CABLE ANCHORAGE Oct; 3, 1967' 2 Sheets-Sheet 1 INVENTOR 7 00/ 1/. Qw'mby Filed March 4, 1966 P. J. QUIMBY CABLE ANCHORAGE Oct. 3, v1967 2 Sheets-Shed 2 Filed March 4, 1966 INVENTOR 1 00/ J Ow'mb United States Patent M 3,344,452 CABLE ANCHORAGE Paul J. Quimby, Bethlehem, Pa., assignor to Bethlehem Steel Corporation, a corporation of Delaware Filed Mar. 4, 1966, Ser. No. 531,725 2 Claims. (Cl. 14-21) This invention relates to multiple strand cable anchorages such as may be used to anchor suspension bridge cables, and particularly to the adjustment of such anchorages for the splay angle of the cable.
Where each individual strand of a multiple strand cable is individually anchored a considerable splay angle of the individual strands from each other is required near the anchorage so that the individual strands may be far enough apart at the anchorage to accommodate the necessary anchoring structure between them. It is therefore necessary to design the anchorage to accommodate the splay angle. This is ordinarily done by special structural elements that are designed to deflect the strands from straight and parallel alignment within the anchorage to the particular individual splay angles of the individual strand immediately outside the anchorage, or by special structural elements each of which is individually shaped to adapt the anchorage to the particular splay angle of an individual strand.
It is an object of the present invention to provide a simple, economical means for adjusting for splay angle in multiple strand cable anchorages without the use of special expensive anchorage structural parts to allow for the splay angle of each individual strand of the cable.
The present invention involves the use of a pre-rotatable spool, having an inclined strand-fitting groove about the periphery, as an anchorage element for each strand. Each spool is rotated when the cable is anchored until the inclination of its groove in the plane of the required adjustment is the same as the splay angle of the strand which is being anchored.
In the figures:
FIGURE 1 shows a diagrammatic elevation of a cable anchorage according to the present invention.
FIGURE 2 shows in elevation a detail of the anchorage means according to the present invention.
FIGURE 3 is a top plan view of the detail of FIG- URE 2.
FIGURE 4 is a vertical section with parts omitted of the detail shown in FIGURE 2, along the line 4-4 of FIGURE 2.
FIGURE 5 shows a detail of a portion of the anchorage.
FIGURE 6 is a detail of a rotatable spool of the present invention.
A multiple strand cable 11 is shown in FIGURE 1 splayed at splay saddle 13 from which individual cable strands 15 diverge to anchorage 17. Anchor bars 19 are fixed in concrete base 21, as shown, connected together and braced by concrete-bearing members 23 which are suitably composed of channel beams welded to anchor bars 19. Anchor plates 25, which may be integral with, or otherwise suitably attached to, anchor bars 19 across the top thereof, extend from concrete base 21 and are partially supported by shoe 27 which may suitably comprise an I-bearn 29 and a bracket 31 resting on base 21 and partially supporting anchor plates 25. A series of anchorage pins 33 pass at intervals through anchor plates along the side away from anchor bars 19. Seven anchorage pins 33 pass through each anchor plate 25 tying it to the remaining plates. Each anchorage pin is secured in the anchor plates 25 by nuts 35 threaded on the ends of the pins.
Between adjacent anchor plates 25 a spool 37 is threaded over each anchorage pin 3-3. Each spool 37 has an in- 3,344,452 Patented Get. 3, 1967 clined groove 39 machined about its periphery. The inclination of this groove from an angle perpendicular to the axis of the spool is the same or greater than the greatest splay angle which is'to be encountered in the particular cable installation being anchored, or, more preferably, the greatest angle which is to be encountered in any normal cable anchorage employing that particular sized spool. It will be understood that the axis of the spool corresponds to the axis of the anchorage pin 33 passing through the spool. The spools 37 are preferably the same Width as the desired distance between anchor plates 25.
On the end of each strand 15 of cable 11 in FIGURES 1 through 3 and 5 is secured an anchorage fitting 41 comprising a socket bowl 43. Socket bowl 43 will usually be of the zinc-poured type wherein the ends of the strand are broomed and inserted into a conical orifice in the socket bowl and molten zinc metal is then poured into the orifice and allowed to solidify around the broomed wires. As may be seen in the figures, socket bowls 43 are broader than they are thick. Each broad portion is pierced by cylindrical openings through which are passed U-bolts 45 which are secured in socket bowl 43 by nuts 47 and lock nuts 49. The curved sections of U-bolts 45 are designed to be the correct size and shape to fit in the inclined grooves 39 in spools 37.
Prior to the attachment of the strands 15 to anchorage 17, socket bowls 43 will be already attached to the ends of the strands. U-bolts 45 are passed over spools 37 and the ends are passed through the cylindrical openings in the broad portions of socket bowls 43 and secured by nuts 47. Spools 3-7 are then rotated until the angle of the groove with respect to a plane perpendicular to the axis of the spool is the same as the splay angle of the particular strand in the horizontal direction. Alternatively, the entire anchorage may be assembled prior to shipment to the job site, with spools 37 pre-set to their proper rotated positions.
After the inclination of the groove 39 is adjusted to the horizontal splay angle of the strand by rotating spool 37, U-bolt 45 is seated in groove 39 at the rear of the spool and nuts 47 are drawn up until the strand is drawn tight with the desired tension. After the correct tension is attained in the strand, lock nuts 49 are rotated to lock nuts 47 in position.
It will be understood that the splay of the strands 15 in a vertical direction is adjusted for by pivoting of the anchorage fitting 41 about anchorage pins 33 and spools 37 in the normal manner. After anchorage fittings 41 and spools 37 are correctly adjusted, nuts 35 may be tightened to secure the entire assembly together and prevent spools 37 from rotating unless this has already been done in prior assembly as noted heretofore.
By the use of the present invention it is possible to adjust for the splay angles of structural cables at cable anchorages by the use of only one standard splayangleadjustment fitting and the necessity of fabricating or having on hand either a multiplicity of special and expensive strand-deflecting parts, or a number of different cable anchorage fittings, is thus avoided.
1. A multiple strand cable anchorage adjustable for strand splay comprising:
(a) a plurality of spaced anchorage members,
(b) at least one pivot pin passing through the anchorage members,
(c) circumferen-tially grooved spools rotata-bly mounted over the pivot pin between the anchorage members,
(d) the circumferential grooves of at least some of the spools being inclined at an angle from a plane perpendicular to the axis of the spool.
'2 A IJ 2. A cable anchorage according to claim 1 additionally References Cited comprising:
(e) strand sockets arranged to be connected to the UNITED STATES PATENTS pivot pins through the spools mounted thereon be- 1,592,481 7/1926 Dunne 24134 tween the anchorage plates by means of spool en- 5 2,161,337 6/1939 Cordova 52-695 X circling connecting means fitting into the grooves of the spools, FOREIGN PATENTS (f) each spool being rotationally positioned so that 583,508 1/1925 France.
the inclination of its groove in a plane oblique to the axis of the pivot pin substantially matches the 10 BERNARD A GELAKI Primary Examiner angle of approach of the strand in this plane.