Strand anchor

Abstract

A strand anchor, especially for use in mining, comprising a strand having several wires, an anchor head, an anchor plate supported by the anchor head for placement onto the rock, should make it possible to discharge the displaced air when the curable material is being injected into a drilled hole, without the need for a separate hose. At least one longitudinal channel, preferably a plurality of longitudinal channels, is/are formed between the wires of the strand, so that air can be discharged to the outside through the strand through the at least one longitudinal channel when the curable material is being injected into a drilled hole.

1 . A strand anchor comprising:
 a strand including a plurality of wires;   an anchor head;   an anchor plate supported by the anchor head for placement onto rock;   the plurality of wires defining at least one longitudinal channel between the wires of the strand, the at least one longitudinal channel permitting air to be discharged to an outside through the strand through the at least one longitudinal channel when a curable material is injected into a drilled hole.   
     
     
         2 . The strand anchor as recited in  claim 1  wherein the wires have different diameters. 
     
     
         3 . The strand anchor as recited in  claim 2  wherein a first diameter of a first wire of the plurality of wires is at least 10% larger than a second diameter of a second wire of the plurality of wires. 
     
     
         4 . The strand anchor as recited in  claim 3  wherein a first diameter of a first wire of the plurality of wires is at least 20% larger than a second diameter of a second wire of the plurality of wires. 
     
     
         5 . The strand anchor as recited in  claim 4  wherein a first diameter of a first wire of the plurality of wires is at least 30% larger than a second diameter of a second wire. 
     
     
         6 . The strand anchor as recited in  claim 2  wherein at least one of the following is present:
 the wires are configured with an essentially circular cross section and lie on each other, so that each longitudinal channel is delimited by the wires; and 
 a cross-sectional surface area of a flow, or a sum of the cross-sectional surface areas of the flow, of the at least one longitudinal channel is at least 0.1 mm 2 . 
 
     
     
         7 . The strand anchor as recited in  claim 6  wherein a cross-sectional surface area of a flow, or a sum of the cross-sectional surface areas of the flow, of the at least one longitudinal channel is at least 0.5 mm 2 . 
     
     
         8 . The strand anchor as recited in  claim 7  wherein a cross-sectional surface area of a flow, or a sum of the cross-sectional surface areas of the flow, of the at least one longitudinal channel is at least 1 mm 2 . 
     
     
         9 . The strand anchor as recited in  claim 8  wherein a cross-sectional surface area of a flow, or a sum of the cross-sectional surface areas of the flow, of the at least one longitudinal channel is at least 2 mm 2 . 
     
     
         10 . The strand anchor as recited in  claim 9  wherein a cross-sectional surface area of a flow, or a sum of the cross-sectional surface areas of the flow, of the at least one longitudinal channel is at least 5 mm 2 . 
     
     
         11 . The strand anchor as recited in  claim 10  wherein a cross-sectional surface area of a flow, or a sum of the cross-sectional surface areas of the flow, of the at least one longitudinal channel is at least 10 mm 2 . 
     
     
         12 . The strand anchor as recited in  claim 6  wherein each longitudinal channel is delimited by three wires. 
     
     
         13 . The strand anchor as recited in  claim 2  wherein the at least one longitudinal channel includes a plurality of longitudinal channels. 
     
     
         14 . The strand anchor as recited in  claim 13  wherein the plurality of longitudinal channels includes at least 5 longitudinal channels. 
     
     
         15 . The strand anchor as recited in  claim 14  wherein the plurality of longitudinal channels includes at least 10 longitudinal channels. 
     
     
         16 . The strand anchor as recited in  claim 15  wherein the plurality of longitudinal channels includes at least 20 longitudinal channels. 
     
     
         17 . The strand anchor as recited in  claim 16  wherein the plurality of longitudinal channels includes at least 30 longitudinal channels. 
     
     
         18 . The strand anchor as recited in  claim 1  further comprising a plurality of individual wires and at least one spacer, the individual wires being held concentrically with respect to the strand by the at least one spacer. 
     
     
         19 . The strand anchor as recited in  claim 18  wherein the individual wires are arranged at a distance from the strand. 
     
     
         20 . The strand anchor as recited in  claim 1  wherein the strand anchor is a mining strand anchor. 
     
     
         21 . The strand anchor as recited in  claim 1  wherein the at least one longitudinal channel includes a plurality of longitudinal channels. 
     
     
         22 . A method for setting a strand anchor comprising the following steps:
 drilling a hole into rock;   inserting a strand of the strand anchor into the drilled hole;   injecting curable material into the drilled hole in the area of an entrance of the drilled hole; and   discharging from the drilled hole air displaced by the curable material at least partially through at least one longitudinal channel present in the strand.   
     
     
         23 . The method as recited in  claim 22  wherein the air flows through a back end of the at least one longitudinal channel at a back end of the strand into the at least one longitudinal channel and through a front end of the at least one longitudinal channel at a front end of the strand. 
     
     
         24 . The method as recited in  claim 23  wherein the front end is outside of the drilled hole. 
     
     
         25 . The method as recited in  claim 22  wherein after the curable material has been injected into the drilled hole, the curable material is brought into contact with an outside of the strand so that a mechanical connection is established with the strand after the curable material has cured. 
     
     
         26 . The method as recited in  claim 25  wherein the strand anchor includes a plurality of individual wires around the strand, and the curable material forms a mechanical connection with an outside of the individual wires and between the strand and the individual wires. 
     
     
         27 . The method as recited in  claim 22  wherein, after the curable material has cured, a tensile force is applied to the strand via an anchor head. 
     
     
         28 . The method as recited in  claim 27  wherein the curable material is mortar or synthetic resin. 
     
     
         29 . The method as recited in  claim 27  wherein the tensile force also is applied to individual wires of the strand anchor surrounding the stand. 
     
     
         30 . The method as recited in  claim 22  further comprising, after the hole has been drilled and before the strand has been inserted, inserting a cartridge containing another curable material into the drilled hole. 
     
     
         31 . The method as recited in  claim 22  wherein the strand anchor comprises:
 the strand including a plurality of wires; 
 an anchor head; 
 an anchor plate supported by the anchor head for placement onto rock; 
 the plurality of wires defining the at least one longitudinal channel between the wires of the strand, the at least one longitudinal channel permitting air to be discharged to an outside through the strand through the at least one longitudinal channel when the curable material is injected into the drilled hole. 
 
     
     
         32 . The method as recited in  claim 22  wherein the air is discharged completely. 
     
     
         33 . The method as recited in  claim 22  wherein the at least one longitudinal channel includes a plurality of longitudinal channels.