EP4166750B1 - Ankergehäuselastabsorber - Google Patents

Ankergehäuselastabsorber Download PDF

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Publication number
EP4166750B1
EP4166750B1 EP22185478.9A EP22185478A EP4166750B1 EP 4166750 B1 EP4166750 B1 EP 4166750B1 EP 22185478 A EP22185478 A EP 22185478A EP 4166750 B1 EP4166750 B1 EP 4166750B1
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EP
European Patent Office
Prior art keywords
bolting
washer
tapered shaft
diameter
bolt
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
EP22185478.9A
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English (en)
French (fr)
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EP4166750A1 (de
Inventor
Krzysztof Skrzypkowski
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Akademia Gomiczo Hutnicza
Original Assignee
Akademia Gomiczo Hutnicza
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Publication of EP4166750A1 publication Critical patent/EP4166750A1/de
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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
    • E21D21/02—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection having means for indicating tension
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
    • E21D21/0026—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts
    • E21D21/0046—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts formed by a plurality of elements arranged longitudinally
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
    • E21D21/0086—Bearing plates

Definitions

  • the subject of the invention is a roof bolting load absorber for use especially in the roofing of underground mine workings exposed to additional dynamic loads from shocks and damping.
  • Polish patent description PL226879B1 discloses a dynamometric bolting washer comprising a pair of cylinders, outer and inner, facing concave sides to each other and able to slide freely over each other, containing at least one elastic element providing resistance to the sliding cylinders, with the washer having coaxial centrally located holes in both cylinders and the elastic element(s).
  • a device On the rod, between the outline of the excavation (e.g., the roof) and the nut or head of the bolting, a device is placed, which is also a dynamometric bolting washer, consisting of two cylinders, between which there are calibrated elastic elements that absorb the energy of the bolting load.
  • a device On the inner cylinder, measuring rings are placed using a tight fit that prevents them from slipping on their own, but can shift due to the relative displacement of the cylinders. The thickness of each measuring ring is selected according to the load-deformation characteristics of the elastic element.
  • a bolting load indicator is known, which is installed between the bolting washer and the excavation surface.
  • the indicator consists of disc springs bounded by two flat thrust washers.
  • the disc springs form the lining component of the bolting that operates as a load absorber for the roof bolting.
  • the lower washer on the side of the excavation has a hole in which there is a threaded sleeve. Inside the sleeve there is a pin that can slide along the longer sleeve.
  • the upper inner part of the sleeve has a spring wound around the pin to ensure constant contact with the upper thrust washer.
  • the extended part of the pin on the excavation side consists of two distinctive sections. The first outer section, extending beyond the nut, is painted black, while the second section, hidden in the nut, is painted red. During the installation of the roof bolting, an initial tension force is given until the pin extends so that the section marked in black shows. Under the influence of the load, the disc springs are compressed, and the pin slides out of the measuring sleeve. The value of the load is inferred from the appearance, the ejection of the section of the pin painted in red.
  • the load on the bolting can be qualitatively estimated.
  • the moving pin can cause the closing of an electrical circuit, connected to the signalling device.
  • the disc springs are enclosed inside two cylinders, with the inner one, located on the side of the excavation, painted red, and the outer one having holes made in the cylindrical wall. After installing the bolting with the indicator, the protruding parts are spray-painted white. When there is any relative movement of the cylinders, caused by a change of force in the bolting, the red parts of the inner cylinder become visible through the holes in the outer cylinder.
  • a bolting load indicator is known, containing a prone element, which has the form of a sleeve with weakened walls, on the side of which four, symmetrically spaced, longitudinal holes are made.
  • the sleeve is placed on the end of the bolting protruding from the rock mass, between its washer and nut.
  • the indicator is inserted on the end of the bolting protruding from the rock mass, between its washer and nut.
  • the weakened sleeve walls lose stability, resulting in swelling and a decrease in sleeve height, signalling the magnitude of the forces applied to the bolting.
  • polish patent description PL192588B1 in which the energy absorber, in a variant embodiment designed for mining boltings, contains two sections of thin-walled columns of different lengths and different wall thicknesses, which are placed concentrically between plates that are typical flat washers used in boltings.
  • the absorber elements are connected to each other by a bolting rod, one end of which is fixed in the rock mass, while the other passes through holes in the washers and is provided with a nut.
  • An additional energy of the sudden load of the bolting is absorbed by way of forcing a deformation of the thin-walled columns. Visual evaluation of the permanent deformation of the columns can also provide general information about the load put on the bolting. 11
  • the aim of the invention is to develop a roof bolting component that would allow the elastic lining of the bolting in cases of dynamic loading, as well as the dissipation of certain amount of the elastic energy that occurs in the bolting rod, and that would allow a quick visual estimate of the magnitude of the tensile forces or the degree of strain on the bolting.
  • the essence of the load absorber of the roof bolting is that it consists of a dome bolting washer and a special bolt having at one end a cylindrical section provided with a thread passing into a tapered shaft, the diameter of which increases towards the second end, equipped with a head of any known shape, while in the working position, the bolt is passed through a hole in the dome bolting washer, inverted convexly towards the excavation and connected to the bolting rod by means of a connecting sleeve, screwed onto the threaded end of the bolting rod and onto the threaded cylindrical section of the bolt so that the hole of the dome bolting washer encompasses tapered shaft of the bolt in the vicinity of half of its length, and, in addition the section of the tapered shaft on the head side has a strain marker.
  • strain marker consists of at least two circumferential undercuts of the diameter of the tapered shaft.
  • strain marker consists of at least one pitch applied along the generatrix of the cone.
  • strain marker consists of at least two wooden or plastic rods, passed through radial through-holes made in the tapered shaft.
  • fig. 1 shows a simplified view of an energy absorber mounted on an bolting rod in the excavation roof, with a strain marker in the form of circumferential diameter undercuts
  • fig. 2 a fragment of the bolt with a pitch applied by laser technique on the generatrix of the cone
  • fig. 3 - a fragment of the bolt with the pitch in the form of bars going through the radial through-holes made in the tapered shaft of the screw.
  • the load absorber of the roof bolting is located at the end of bolting rod 1, installed in hole 2, made in roof 3 of the mine workings ( fig. 1 ).
  • the special bolt is pulled through a hole in the dome bolting washer 6, turned convexly towards the excavation, and is connected to bolting rod 1 by means of a connecting sleeve 4, screwed onto the threaded end of bolting rod 1 and onto threaded cylindrical section 5a of the special bolt.
  • the cylindrical section 5a passes into tapered shaft 5b with a diameter that increases toward the other end of the bolt, equipped with head 5d of hexagonal shape.
  • the dimensions of the tapered shaft 5b are selected so that its diameter near the middle of its length is equal to the diameter of the hole of dome bolting washer 6 and when the initial tension force of bolting 1 is set the hole of dome bolting washer 6 covers the tapered shaft 5b at a distance not exceeding 0.6 of its length, measured from its narrower end.
  • the section of tapered shaft 5b, extending beyond bolting washer 6, has strain marker 5c, which is constituted by three circumferential stem extension of its diameter, each of which is additionally filled with a different colour of paint.
  • the distances between the stem extensions of strain marker 5c and their location on tapered shaft 5b are chosen so that the first stem extension corresponds to the magnitude of the initial tension force of bolting 1, the second stem extension corresponds to the value of half of the breaking force of bolting 1, and the third stem extension corresponds to the value of the force inducing in bolting 1 stresses equal to the elastic limit of the material of which the bolting rod 1 is made.
  • the scaling of the strain marker 5c is performed on the basis of the results of laboratory tests involving the pulling of tapered shaft 5b through domed washer 6, during which the force and the corresponding relative displacement of the two elements are measured.
  • the strain marker 5c is a graduated marker applied by laser technique on the forming surface of the tapered shaft 5b on its two opposite sides ( fig. 2 ).
  • the strain marker 5c of bolting 1 is constituted by three rods pulled through radial through-holes made in the tapered shaft 5b of the bolt at distances corresponding to known values of longitudinal forces in bolting 1, successively: the initial tension force of bolting 1, a force equal to half of the breaking force of bolting 1, and a force inducing in bolting 1 stresses equal to the elastic limit of the material of which the bolting rod 1 is made ( fig. 3 ).
  • the rods can be made of any material with low shear strength and can have different colours, indicating the achieved degree of strain on the bolting 1 or the longitudinal force in the bolting 1.
  • the strain marker 5c is calibrated so that it indicates only two states of load on the bolting: the initial tension force of bolting 1 and the force causing the attainment of stress in bolting 1 at the elastic limit of the material of which bolting 1 is made.
  • the operation of the roof bolting load absorber is that after the bolting is installed in the rock mass, an initial tension force is given so that the edge of the hole of the dome bolting washer 6 coincides with the first marking on tapered shaft 5b.
  • additional tensile forces may occur, for example, due to delaminations occurring in the roof of the mine workings, the increment of which is quasi-static.
  • the energy of elastic deformation is dissipated gradually as tapered shaft 5b is pulled through the hole of the dome bolting washer 6, i.e. to overcome the frictional resistance and the elastic and plastic deformation of the hole of the dome bolting washer 6.
  • strain marker 5c Thanks to the marked pitch on the strain marker 5c, information on the working point of boltings 1 can be read, and it is possible to decide on the application of additional excavation protection.
  • domed bolting washer 6 by deforming elastically and plastically, provides a bolting lining.
  • the readings of strain marker 5c are not authoritative, and only the fact of deformation of domed bolting washer 6 is noted, so that it is possible to determine the sections of excavations with compromised stability that should be fenced off or where additional protective measures should be applied.

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  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Structural Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Force Measurement Appropriate To Specific Purposes (AREA)
  • Piles And Underground Anchors (AREA)

Claims (5)

  1. Lastabsorber der Dachverankerung, der eine Verbindung mit dem in das Gesteinsmaterial eingebetteten Ende der Verankerung hat, dadurch gekennzeichnet, dass er aus einer kuppelförmigen Verankerungsscheibe (6) und einem speziellen Bolzen besteht, der an einem Ende einen mit einem Gewinde versehenen zylindrischen Abschnitt (5a) aufweist, der in einen sich verjüngenden Schaft (5b) übergeht, dessen Durchmesser zum anderen Ende hin zunimmt, und der mit einem Kopf (5d) mit beliebiger Form versehen ist, wobei der Bolzen in der Arbeitsposition durch ein Loch in der kuppelförmigen Verankerungsscheibe (6) geführt wird, in der Arbeitsposition durch ein Loch in der gewölbten Verankerungsscheibe (6) geführt wird, konvex zum Aushub hin umgedreht und mit der Verankerungsstange (1) mittels einer Verbindungsmuffe (4) verbunden wird, die auf das Gewindeende der Verankerungsstange (1) und auf den zylindrischen Gewindeabschnitt (5a) des Bolzens geschraubt wird, so dass das Loch der gewölbten Verankerungsscheibe (6), das Loch der Kuppelscheibe (6), den konischen Schaft (5b) des Bolzens in der Nähe der Hälfte seiner Länge umfasst und außerdem der Abschnitt des konischen Schafts (5b) auf der Seite des Kopfes (5d) eine abgestufte Dehnungsmarkierung (5c) aufweist.
  2. Absorber nach Anspruch 1, dadurch gekennzeichnet, dass der Der Abschnitt des konischen Schafts (5b), dessen Durchmesser dem Durchmesser des Lochs der gewölbten Verschraubungsscheibe (6) entspricht, befindet sich in einem Abstand, der 0,4 bis 0,6 seiner Länge entspricht.
  3. Absorber nach Anspruch 1, dadurch gekennzeichnet, dass die Dehnungsmarkierung (5c) aus mindestens zwei umlaufenden Hinterschneidungen des Durchmessers der konischen Welle (5b) besteht.
  4. Absorber nach Anspruch 1, dadurch gekennzeichnet, dass die Dehnungsmarkierung (5c) aus mindestens einer Teilung besteht, die entlang der Mantellinie des Kegels angebracht ist.
  5. Absorber nach Anspruch 1, dadurch gekennzeichnet, dass die Dehnung
    Die Markierung (5c) besteht aus mindestens zwei Holz- oder Kunststoffstäben, die durch radiale Durchgangslöcher in der kegelförmigen Welle (5b) geführt werden.
EP22185478.9A 2021-07-20 2022-07-18 Ankergehäuselastabsorber Active EP4166750B1 (de)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PL438538A PL438538A1 (pl) 2021-07-20 2021-07-20 Absorber obciążenia obudowy kotwowej

Publications (2)

Publication Number Publication Date
EP4166750A1 EP4166750A1 (de) 2023-04-19
EP4166750B1 true EP4166750B1 (de) 2024-06-05

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EP22185478.9A Active EP4166750B1 (de) 2021-07-20 2022-07-18 Ankergehäuselastabsorber

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EP (1) EP4166750B1 (de)
PL (1) PL438538A1 (de)

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2850937A (en) * 1955-04-28 1958-09-09 Eldon K Ralston Snap type bolt tension indicator
US3133468A (en) * 1961-03-21 1964-05-19 James D Cumming Tension indicating device
CA2018970A1 (en) 1990-06-13 1991-12-13 Gordon R. Friesen Rockbolt load indicator
AU664186B2 (en) * 1991-08-30 1995-11-09 Technological Resources Pty Limited Rock bolt load sensor
RO118766B1 (ro) * 1999-03-02 2003-10-30 Adam Szabo Aparat pentru monitorizarea sarcinii axiale a ancorelor miniere
PL192588B1 (pl) 2000-12-15 2006-11-30 Glowny Instytut Gornictwa Absorber energii
PL67289Y1 (pl) 2012-03-26 2014-07-31 Główny Inst Górnictwa Indykator obciążenia kotwi
PL226879B1 (pl) 2014-07-11 2017-09-29 Akademia Górniczo Hutnicza Im Stanisława Staszica W Krakowie Sposób pomiaru obciazenia kotwy oraz dynamometryczna podkładka kotwowa
WO2017214639A1 (en) * 2016-06-09 2017-12-14 Ncm Innovations (Pty) Ltd Progressive load indicator

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Publication number Publication date
PL438538A1 (pl) 2023-01-23
EP4166750A1 (de) 2023-04-19

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