COMPOSITE ANCHOR Russian patent published in 2007 - IPC E21D21/00 

FIELD: land-based and underground building structures and mining, namely anchoring-bolts for roof, floor, or shaft-lining protection, particularly anchors formed of composites based on fiber material and polymeric binder.

SUBSTANCE: anchor comprises fixing assembly including nut 1 with splins for key and sectional rod. Rod 3 comprises three sections, namely head section 4, end section 5 and one intermediate section 6. Each rod section has central channel 7 of constant diameter. Sections 4, 6 and sections 5 are connected with each other through threaded bushes 10 provided with internal threads flush with sections 4, 5, 6 to be connected. To provide bush flushing with sections outer threaded areas 11 are formed on end of each section. Drilling bit 24 and nut 1 are screwed on section 4, 5 ends free of connection with other sections correspondingly. Shaped extensions 12 are formed on section 4 surface. Surfaces of sections 5, 6 are covered with sacrificial layer 25. Rod 3 sections free of sacrificial layer 25, threaded bushes 10 and nut 1 are made of fiberglass based on fiber material and epoxy binder. Sacrificial layer 25 is made of glass tissue based material impregnated with the same resin. Volumetric ratio between each section 4, 5, 6 fiber and thread, bundle or band fiber of sacrificial rod layer 25 is 1:0.3. Total volumetric binder content in any section is 30%.

EFFECT: increased operational reliability.

18 cl, 15 dwg