Apparatus and methods for tensioning cables

Claim 2

A jack for simultaneously tensioning a plurality of cables each projecting through a wedge-shaped bore in an anchor assembly and for anchoring the cables to a structure after tensioning by seating anchor wedges in the corresponding wedge-shaped bores, comprising: a jack body having a front end for operatively abutting the structure during tensioning, and further having a longitudinal passage therein opening at the front end into a mouth for receiving the cables; a tensioning head disposed within the jack body passage for oneto-one gripping of each cable, said tensioning head including (1) gripping means for gripping each cable, (2) unclamping means adapted for longitudinal movement relative to the gripping means from a disengaged position at which the unclamping means is inoperative to release the gripping means to an engaged position at which the unclamping means is operative to release the griping means, and (3) resilient means normally urging the unclamping means to the disengaged position; a plate having a plurality of bores arranged in a pattern corresponding to that of the gripping means, the plate being adapted to be threaded onto the cables independently of the jack body and positioning closely adjacent the free ends of the cables to align the cables ends in the pattern of the gripping means so that the cable ends are held by the plate in proper alignment for receipt by the gripping means upon insertion of the jack body over the cables; means for urging the tensioning head to a position adjacent the mouth of the jack body, so as to bring the plate and the tensioning head adjacent each other and to allow substantially simultaneous receipt of the cable ends by the gripping means upon insertion of the jack body over the cables, and for urging the tensioning head away from the housing to simultaneously tension the cables; and means for engaging the plate to drive the anchor wedges into their corresponding wedge-shaped bores, whereby the cables are anchored to the structure in their tensioned state.

Claim 3

The jack according to claim 1 wherein the plate is dimensioned to be received axially within the mouth of the jack body.

Claim 4

The jack according to claim 1: wherein the gripping means comprises a gripping plate having a plurality of wedge-shaped bores and gripping jaws for seating in the bores to grip the cables extending therethrough; wherein the unclamping means includes means for selectively pulling the gripping jaws out of their corresponding bores in the gripping plate to release the cables from the gripping jaws; and the jack further including biasing means for urging the gripping jaws into their corresponding wedge-shaped bores.

Claim 5

The jack according to claim 1: wherein the gripping means comprises a gripping plate having a plurality of wedge-shaped bores and gripping jaws for seating in the bores in the gripping plate to grip the cables extending therethrough; and wherein the tensioning head further includes means for urging the gripping jaws into their corresponding bores comprising a pressure plate having a plurality of bores arranged in a pattern corresponding with that of the gripping jaws and aligned therewith, the pressure plate being mounted to the rearward side of the gripping plate and spaced a predetermined distance therefrom, a tubular member coupled with the bases of the gripping jaws and extending through the corresponding bores in the pressure plate, and a spring means associated with each tubular member between the gripping jaws and the pressure plate.

Claim 6

The jack according to claim 4 wherein the spring means comprises a series of conical rings surrounding the tubular member.

Claim 7

The jack according to claim 4 further including a pulling plate mounted rearwardly of the pressure plate to the ends of the tubular members extending through the bores in the pressure plate and means for selectively pulling the pulling plate rearwardly to pull the jaws out of their corresponding bores in the gripping plate when the jack is to be removed from the cables after tensioning.

Claim 8

The hydraulic jack according to claim 3 wherein the biasing means includes a pressure plate in fixed spaced relation to the gripping plate, a plurality of tubular members each fastened to a gripping jaw and slidably extending through the pressure plate, the tubular members receiving the cables during tensioning, a plurality of conical rings each associated with and surrounding a tubular member between the jaws and the pressure plate, the conical rings alternately disposed so as to form a resilient assembly tending to bias the gripping jaws towards the corresponding bores in the gripping plate; and the means selectively pulling includes a pulling plate having a plurality of bores arranged in a pattern corresponding to that of the gripping jaws and aligned therewith, the pulling plate axially positioned to the rear of the pressure plate and engaging the free ends of the tubular members, and means for moving the pulling plate rearwardly to pull the jaws out of their corresponding bores in the gripping plate.

Claim 9

A jack according to claim 1 wherein: the gripping means includes a gripping plate having a plurality of wedge-shaped bores and gripping jaws for seating in the bores in the gripping plate to grip the cables extending therethrough; and the unclamping means being adapted to coact with stop means located adjacent the mouth of the jack body, the unclamping means includes an unclamping plate having a plurality of hollow stubs, each mounted in a bore in the unclamping plate, the bores in the unclamping plate arranged in a pattern corresponding to that of the gripping jaws, the unclamping plate being slidably positioned axially in the passage and slidably attached to the gripping plate side closest to the mouth, the stubs being retained within the bores in the gripping plate to engage the gripping jaws and drive them out of their corresponding bores upon movement of the unclamping plate into engagement with the stop means.

Claim 10

A jack according to claim 1, wherein the tensioning head urging means includes: a plunger attached to the tensioning head and slidable within the passage and having a bore to receive the cables, the plunger further having a first external step and the passage having a corresponding first internal step facing the first external step, the first external step and the first internal step forming the opposite ends of a first fluid-tight expansible pressure chamber between the plunger and the jack body, the plunger further having a second external step and the passage having a second internal step facing the second external step, the second external and the second internal step forming opposite ends of a second fluid-tight expansible pressure chamber between the plunger and the jack body; means for introducing hydraulic fluid into the first pressure chamber to move the plunger away from the mouth to simultaneously tension the cables; and means for introducing hydraulic fluid into the second pressure chamber to move the plunger into said position adjacent the mouth.

Claim 11

A jack according to claim 9, wherein the plate engaging means includes: a striker piston having an external step and the passage having a corresponding third internal step facing the striker piston external step, the striker piston external step and the third internal step forming the opposite ends of a third fluid-tight expansible pressure chamber between the striker piston and the jack body; and means for introducing hydraulic fluid into the third pressure chamber to move the striker piston towards the mouth to drive the anchor wedges into their corresponding bores in the anchor assembly.

Claim 12

A jack according to claim 1, wherein: the tensioning head urging means includes a plunger slidable in the passage and having an annular shoulder defining a double acting piston and means for hydraulically driving the piston towards and away from the mouth of the jack body; and the plate engaging means includes a single acting striker piston slidable in the passage adjacent the mouth thereof for driving the anchor wedges into their corresponding wedge-shaped bores in the anchor plate to anchor the cables, the striker piston having an external annular shoulder and the passage having a corresponding internal annular shoulder and the external and internal shoulders forming the opposite ends of an annular expanSible fluid-tight pressure space, and means for introducing hydraulic fluid into the annular space to move the striker piston toward the anchor plate to move the wedges into their corresponding wedge-shaped bores.

Claim 13

The jack according to claim 11 in which the working area of the face of the plunger piston which is effective to move the plunger away from the mouth is greater than the working area of the other face of the plunger piston which is effective to move the plunger back towards the mouth.

Claim 14

A jack for simultaneously tensioning a plurality of cables each projecting through a wedge-shaped bore in an anchor assembly and for anchoring the cables to a structure after tensioning by seating anchor wedges in the corresponding wedge-shaped bores, comprising: a jack body having a front end for operatively abutting the structure during tensioning and further having a longitudinal passage therein opening at the front end into a mouth for receiving the cables; a tensioning head mounted within the passage for movement longitudinally thereof; gripping means carried by the tensioning head for gripping said plurality of cables, said gripping means including (1) a gripping plate having formed therein a corresponding plurality of wedge-shaped bores for receipt of the cables and (2) gripping jaws adapted to be seated in the bores for gripping the cables to enable tensioning thereof; unclamping means carried by the tensioning head for releasing the gripping jaws upon tensioning of the cables, said unclamping means including (1) an unclamping plate mounted on the side of the gripping plate nearest the passage mouth for limited longitudinal movement towards and away from the gripping plate and having formed therein a plurality of bores generally corresponding in number and arrangement to the bores of the gripping plate, (2) means carried by the unclamping plate in association with each bore and protruding therefrom towards the gripping plate for engagement, upon movement of the unclamping plate towards the gripping plate, with the gripping jaws in the corresponding gripping plate bore to force the jaws out of the bore, and (3) resilient means normally urging the unclamping plate away from the gripping plate; means for moving the tensioning head longitudinally within the passage from a forward position at which it is adapted to receive the cables to a rearward position at which the cables are tensioned; stop means located adjacent the passage mouth for limiting movement of the unclamping plate towards the mouth, whereby when the tensioning head is moved towards the mouth the unclamping plate moves corresponding until it is stopped by the stop means whereupon the gripping plate in continuing to move forward moves towards the unclamping plate such that the protruding means engage the gripping jaws and force them out of their corresponding bores in the gripping plates, thereby permitting the jack to be removed from the cables after tensioning; and anchoring means carried by the jack body for driving the anchor wedges into the corresponding wedge-shaped bores, whereby the cables are anchored to the structure in their tensioned state, said anchoring means including an anchoring plate having a plurality of bores arranged in a pattern corresponding to the bores of the gripping plate, the anchoring plate being adapted to be threaded onto the cables independently of the jack body and positioned closely adjacent the free ends of the cables to align the cable ends in the pattern of the gripping means so that the cable ends are held by the plate in proper alignment for receipt by the gripping means upon insertion of the jack body over the cables.

Claim 15

A jack for simultaneously tensioning a plurality of cables each projecting through a wedge-shaped bore in an anchor assembly and for anchoring the cables to a structure after tensioning by seating anchor wedges in the corresponding wedge-shaped bores, comprising: a jack body having a front end for operatively abutting the structure during tensioning and further having a longitudinal passage therein opening at the front end into a mouth for receiving the cables; a tensioning head mounted within the passage for movement longitudinally thereof; gripping means carried by the tensioning head for gripping said plurality of cables, said gripping means including (1) a gripping plate having formed therein a corresponding plurality of wedge-shaped bores for receipt of the cables and (2) gripping jaws adapted to be seated in the bores for gripping the cables to enable tensioning thereof; unclamping means carried by the tensioning head for releasing the gripping jaws upon tensioning of the cables, said unclamping means including (1) an unclamping plate mounted on the side of the gripping plate nearest the passage mouth for limited longitudinal movement towards and away from the gripping plate and having formed therein a plurality of bores generally corresponding in number and arrangement to the bores of the gripping plate, (2) means carried by the unclamping plate in association with each bore and protruding therefrom towards the gripping plate for engagement, upon movement of the unclamping plate towards the gripping plate, with the gripping jaws in the corresponding gripping plate bore to force the jaws out of the bore, and (3) resilient means normally urging the unclamping plate away from the gripping plate; means for moving the tensioning head longitudinally within the passage from a forward position at which it is adapted to receive the cables to a rearward position at which the cables are tensioned; stop means located adjacent the passage mouth for limiting movement of the unclamping plate towards the mouth, whereby when the tensioning head is moved towards the mouth the unclamping plate moves corresponding until it is stopped by the stop means whereupon the gripping plate in continuing to move forward moves towards the unclamping plate such that the protruding means engage the gripping jaws and force them out of their corresponding bores in the gripping plates, thereby permitting the jack to be removed from the cables after tensioning; and anchoring means carried by the jack body for driving the anchor wedges into the corresponding wedge-shaped bores, whereby the cables are anchored to the structure in their tensioned state, said anchoring means including an anchoring plate having a plurality of bores arranged in a pattern corresponding to the bores of the gripping plate, the anchoring plate being adapted to be threaded onto the cables independently of the jack body and positioned closely adjacent the free ends of the cables to align the cable ends in the pattern of the gripping means so that the cable ends are held by the plate in proper alignment for receipt by the gripping means upon insertion of the jack body over the cables.

Claim 16

A jack for simultaneously tensioning a plurality of cables each projecting through a wedge-shaped bore in an anchor assembly and for anchoring the cables to a structure after tensioning by seating anchor wedges in the corresponding wedge-shaped bores, comprising: a jaCk body having a front end for operatively abutting the structure during tensioning and further having a longitudinal passage therein opening at the front end into a mouth for receiving the cables; a tensioning head mounted within the passage for movement longitudinally thereof; gripping means carried by the tensioning head for gripping said plurality of cables, said gripping means including (1) a gripping plate having formed therein a corresponding plurality of wedge-shaped bores for receipt of the cables and (2) gripping jaws adapted to be seated in the bores for gripping the cables to enable tensioning thereof; unclamping means carried by the tensioning head for releasing the gripping jaws upon tensioning of the cables, said unclamping means including (1) an unclamping plate mounted on the side of the gripping plate nearest the passage mouth for limited longitudinal movement towards and away from the gripping plate and having formed therein a plurality of bores generally corresponding in number and arrangement to the bores of the gripping plate, (2) means carried by the unclamping plate in association with each bore and protruding therefrom towards the gripping plate for engagement, upon movement of the unclamping plate towards the gripping plate, with the gripping jaws in the corresponding gripping plate bore to force the jaws out of the bore, and (3) resilient means normally urging the unclamping plate away from the gripping plate; means for moving the tensioning head longitudinally within the passage from a forward position at which it is adapted to receive the cables to a rearward position at which the cables are tensioned; stop means located adjacent the passage mouth for limiting movement of the unclamping plate towards the mouth, whereby when the tensioning head is moved towards the mouth the unclamping plate moves corresponding until it is stopped by the stop means whereupon the gripping plate in continuing to move forward moves towards the unclamping plate such that the protruding means engage the gripping jaws and force them out of their corresponding bores in the gripping plate, thereby permitting the jack to be removed from the cables after tensioning; and means carried by the jack body for driving the anchor wedges into the corresponding wedge-shaped bores, whereby the cables are anchored to the structure in their tensioned state.

Claim 17

A jack for simultaneously tensioning a plurality of cables each projecting through a wedge-shaped bore in an anchor assembly and for anchoring the cables to a structure after tensioning by seating anchor wedges in the corresponding wedge-shaped bores, comprising: a jaCk body having a front end for operatively abutting the structure during tensioning and further having a longitudinal passage therein opening at the front end into a mouth for receiving the cables; a tensioning head mounted within the passage for movement longitudinally thereof; gripping means carried by the tensioning head for gripping said plurality of cables, said gripping means including (1) a gripping plate having formed therein a corresponding plurality of wedge-shaped bores for receipt of the cables and (2) gripping jaws adapted to be seated in the bores for gripping the cables to enable tensioning thereof; unclamping means carried by the tensioning head for releasing the gripping jaws upon tensioning of the cables, said unclamping means including (1) an unclamping plate mounted on the side of the gripping plate nearest the passage mouth for limited longitudinal movement towards and away from the gripping plate and having formed therein a plurality of bores generally corresponding in number and arrangement to the bores of the gripping plate, (2) means carried by the unclamping plate in association with each bore and protruding therefrom towards the gripping plate for engagement, upon movement of the unclamping plate towards the gripping plate, with the gripping jaws in the corresponding gripping plate bore to force the jaws out of the bore, and (3) resilient means normally urging the unclamping plate away from the gripping plate; means for moving the tensioning head longitudinally within the passage from a forward position at which it is adapted to receive the cables to a rearward position at which the cables are tensioned; stop means located adjacent the passage mouth for limiting movement of the unclamping plate towards the mouth, whereby when the tensioning head is moved towards the mouth the unclamping plate moves corresponding until it is stopped by the stop means whereupon the gripping plate in continuing to move forward moves towards the unclamping plate such that the protruding means engage the gripping jaws and force them out of their corresponding bores in the gripping plate, thereby permitting the jack to be removed from the cables after tensioning; and means carried by the jack body for driving the anchor wedges into the corresponding wedge-shaped bores, whereby the cables are anchored to the structure in their tensioned state.