Reaming and Self-Rotating Anchor Rod and Using Method Thereof

Abstract

The present invention provides a reaming and self-rotating anchor rod and a construction method using the reaming and self-rotating anchor rod, which are applicable to supporting for quick tunneling of coal roadways. The reaming and self-rotating anchor rod comprises a rod body, a drill bit, a connecting member, a tray and a nut; one end the connecting member is snap-fixed to the tail part of the rod body, the other end of the connecting member is connected to an anchor rod bolter, the rod body has an annular protrusion at its middle part to block powder so that the powder fills up the clearance between the rod body and the coal mass; the drill bit has female threads and can be screwed into the front part of the rod body, and the drill bit has baffle pawls and spiral grooves on its side surface; a hole in length smaller than the length of the anchor rod is drilled out with an anchor rod bolter first, and then the anchor rod is connected to the anchor rod bolter, the drill bit on the front part of the anchor rod is placed in the preformed hole, and finally the anchor rod is driven to ream and rotate into the coal mass, so as to accomplish the construction with the reaming and self-rotating anchor rod; the reaming and self-rotating anchor rod can shorten supporting time and avoid an abandoned borehole phenomenon incurred by hole collapse or blockage, and anchoring failure, etc., and the anchor rod is simple to manufacture, low in cost, and simple and convenient to operate. Therefore, the anchor rod and the method of using it can be widely applied and can meet the requirement for quick tunneling of coal roadways.

Claims

1. A reaming and self-rotating anchor rod, comprising a rod body, wherein the rod body has threads without longitudinal rib on the external surface and the rod body including an anchoring device and a connecting part in a symmetric wedge on the front and rear of a tail part respectively; a drill bit, wherein the drill bit is arranged at a head part of the rod body; the head part of the rod body connected with the drill bit via a plurality of threads, wherein the pitch of the drill bit is identical to the pitch of the threads without longitudinal rib; a connecting member on the connecting part to facilitate the connection to an anchor rod bolter, an end of the connecting member connected to the rod body is a cylinder with an inverted wedge-shaped cut therein, which matches the symmetric wedge at the tail part of the anchor rod body; wherein, the rod body, the drill bit and the connecting member are interconnected through a threaded connection into a combined structure, and a tightening device, wherein the tightening device comprises a tray and a nut; wherein when the rod body penetrates into a coal seam, the tray is fitted over the tail part of the rod body and is fixed by the nut; wherein an out diameter of the drill bit is greater than the diameter of the anchor rod body by 38 mm, wherein the drill bit has an opening connected with the anchor rod body and a plurality of sharp knives that protrude and incline toward the center of the drill bit are arranged around the opening, the top of each sharp knife being between 3 mm and 5 mm from the center of the drill bit including spiral grooves configured to discharge the slack coal produced during drilling from the drill bit are arranged on the side surface of the drill bit, wherein the spiral grooves are in 5 mm8 mm width and 3 mm5 mm depth; wherein a plurality of baffle pawls are arranged at the clearance between the grooves on the side surface of the drill bit, and each baffle pawl comprises a groove cavity, the groove cavity provides a space for rotation of the high-strength baffle plate, a circular shaft, one side of the bottom of the groove cavity is movably connected with the high-strength baffle plate via the circular shaft, a high-strength baffle plate, and a strong spring, the strong spring being arranged between the high-strength baffle plate and the bottom of the groove cavity, the high-strength baffle plate is ejected by the strong spring and can rotate within the groove cavity via the circular shaft; wherein the symmetric wedge at the tail part of the rod body has a length between 30 mm and 100 mm, and the opening angle of the wedge is between 55 and 75; wherein the rod body has an annular protrusion welded to the rod body between and length of the rod body, the diameter of the annular protrusion is greater than that of the rod body by 3 mm8 mm, and the thickness of the annular protrusion is between 2 mm and 3 mm.

2.-6. (canceled)

7. A method of using the reaming and self-rotating anchor rod according to claim 1, characterized in that, comprising: mounting the drill bit on an ordinary drill rod and mounting the ordinary drill rod on an anchor rod bolter after a roadway is excavated by a tunneling machine, the diameters of the ordinary drill rod and the drill bit are the same and both are smaller than the diameter of the rod body of the reaming and self-rotating anchor rod by 2 mm4 mm; arranging a drilling point for a hole in a coal seam, starting the anchor rod bolter to drill at the drilling point, till the length of the ordinary drill rod penetrating into the coal seam is of the length of the reaming and self-rotating anchor rod, and then stopping the drilling and withdrawing the ordinary drill rod and the drill bit; screwing the drill bit into the front part of the rod body of the reaming and self-rotating anchor rod by means of the threads, placing the drill bit into the hole, keeping the baffle pawls of the drill bit in a closed state and keeping the connecting member for connecting the anchor rod bolter with the rod body in a level state so that the wedge at the tail part of the rod body is right embedded in the connecting member, and then mounting the reaming and self-rotating anchor rod to the anchor rod bolter via the connecting member; starting the anchor rod bolter, driving the reaming and self-rotating anchor rod to advance quickly in the existing small hole to accomplish reaming under the action of the rotation of the drill bit on the front part of the reaming and self-rotating anchor rod and the pushing force applied by a worker, so that friction force is generated between the anchor rod body and the coal seam; decreasing the drilling rate of the anchor rod bolter when that the reaming and self-rotating anchor rod has reached to the bottom of the preformed small hole in the coal seam judged from obvious advancing resistance, utilizing the drill bit on the front part of the anchor rod to rotate the rod body into the coal mass, since the shape knives on the front part of the drill bit are in middle positions, the powder produced during drilling can be discharged away from the head part of the rod body through the spiral grooves on the side surface of the drill bit, the annular protrusion on the rod body blocks the powder flowing out from the hole and thereby the powder fills the clearance between the rod body and the coal mass; shutting down the anchor rod bolter when the exposed length of the anchor rod body is 30 mm150 mm, and separating the connecting member from the symmetric wedge at the tail part of the rod body, since the self-rotation of the anchor rod, there is a force interaction between the connecting member and the rod body, the rod body ought to retreat by some distance together with the connecting member when the connecting member is separated from the rod body, but the strong springs of the baffle pawls on the drill bit eject at this point and the high-strength baffle plates are pushed open and extend out of the groove cavities to block the rod body from further retreating; then, fitting the tray over the tail part of the rod body and mounting the nut on the tail part of the rod body to fix the tray, and using the anchor rod bolter to rotate the nut to accomplish primary pre-tightening of the anchor rod, so that the anchor rod is squeezed and embedded into the coal mass, and thereby the friction force between the anchor rod and the coal mass is increased, the anchor rod is anchored in the full length, and the installation of a complete set of anchor rod is accomplished; at 1 h2 h after the anchor rod works, tightening up the nut with a wrench for secondary pre-tightening, to prevent prestress relaxation of the anchor rod incurred by working of other anchor rods nearby; at 1224 h after the anchor rod works, checking the pre-tightening force on the anchor rod with a torque-indicating wrench, and pre-tightening up the anchor rod again if the pre-tightening force doesn't meet the requirement so that the tray squeezes the cracked coal wall to maintain the pre-tightening force; and repeating the steps to work the next reaming and self-rotating anchor rod.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 is a schematic diagram of the reaming and self-rotating anchor rod during the working process;

[0020] FIG. 2 is a schematic diagram the reaming and self-rotating anchor rod after the working process;

[0021] FIG. 3 is an overall schematic diagram of the drill bit of the reaming and self-rotating anchor rod;

[0022] FIG. 4 is a front view of the tail part of rod body of the reaming and self-rotating anchor rod;

[0023] FIG. 5 is a top view of the tail part of rod body of the reaming and self-rotating anchor rod.

[0024] In the figures: 1rod body; 1-1symmetric wedge; 1-2annular protrusion; 2drill bit; 3connecting member; 4tray; 5nut; 6anchor rod bolter; 7coal seam; 8small hole; 9spiral groove; 10shape knife; 11baffle pawl; 11-1groove cavity; 11-2circular shaft; 11-3high-strength baffle plate; 11-4strong spring.

DETAILED DESCRIPTION

[0025] Hereunder, an embodiment of the present invention will be further detailed with reference to the accompanying drawings.

[0026] As shown in FIGS. 1 and 2, the reaming and self-rotating anchor rod provided in the present invention comprises a rod body 1, a drill bit 2, a connecting member 3, and a tightening device, wherein, the rod body 1 has threads without longitudinal rib on the external surface, the drill bit 2 is arranged at the head part of the rod body 1, the head part of the rod body 1 is connected with the drill bit 2 via threads, and the pitch of the drill bit 2 is identical to that of threads without longitudinal rib.

[0027] As shown in FIG. 3, the out diameter of the drill bit 2 is greater than the diameter of the anchor rod body 1 by 38 mm, the drill bit 2 has an opening connected with the anchor rod body 1, a plurality of sharp knives 10 that protrude and incline toward the center of the drill bit 2 are arranged around the opening, the top of each sharp knife 10 is at 3 mm5 mm distance from the center of the drill bit 2, spiral grooves 9 configured to discharge the slack coal produced during drilling from the drill bit 2 are arranged on the side surface of the drill bit 2, and the spiral grooves 9 are in 5 mm8 mm width and 3 mm5 mm depth. A plurality of baffle pawls 11 are arranged at the clearance between the grooves 9 on the side surface of the drill bit 2, and the baffle pawl 11 comprises a groove cavity 11-1, a circular shaft 11-2, a high-strength baffle plate 11-3 and a strong spring 11-4, wherein, the groove cavity 11-1 provides a space for rotation of the high-strength baffle plate 11-3, one side of the bottom of the groove cavity 11-1 is movably connected with the high-strength baffle plate 11-3 via the circular shaft 11-2, the strong spring 11-4 is arranged between the high-strength baffle plate 11-3 and the bottom of the groove cavity 11-1, the high-strength baffle plate 11-3 is ejected by the strong spring 11-4 and can rotate within the groove cavity 11-1 via the circular shaft 11-2.

[0028] As shown in FIGS. 4 and 5, the rod body 1 has an anchoring device and a connecting part in a symmetric wedge on the front and rear of the tail part respectively, the symmetric wedge 1-1 at the tail part of the rod body 1 is in length of 30 mm100 mm, the opening angle of the wedge is 5575, there is an annular protrusion 1-2 welded to the rod body 1 at of the length of the rod body 1, the diameter of the annular protrusion 1-2 is greater than that of the rod body 1 by 3 mm8 mm, the thickness of the annular protrusion 1-2 is 23 mm, the connecting part has a connecting member 3 to facilitate the connection to the anchor rod bolter 6, an end of the connecting member 3 connected to the rod body 1 is a cylinder with an inverted wedge-shaped cut therein, which matches the symmetric wedge 1-1 at the tail part of the anchor rod body, wherein, the rod body 1, the drill bit 2 and the connecting member 3 are interconnected through a threaded connection into a combined structure; the tightening device comprises a tray 4 and a nut 5; when the rod body 1 penetrates into a coal seam 7, the tray 4 is fitted over the tail part of the rod body 1 and is fixed by the nut 5.

[0029] A method of using the reaming and self-rotating anchor rod described above comprises the following steps:

[0030] a. mounting the drill bit on an ordinary drill rod and mounting the ordinary drill rod on an anchor rod bolter 6 after a roadway is excavated by a tunneling machine, wherein, the diameters of the ordinary drill rod and the drill bit are the same and both are smaller than the diameter of the rod body 1 of the reaming and self-rotating anchor rod by 2 mm4 mm; arranging a drilling point for a hole 8 in a coal seam 7, starting the anchor rod bolter 6 to drill at the drilling point, till the length of the ordinary drill rod penetrating into the coal seam 7 is of the length of the reaming and self-rotating anchor rod, and then stopping the drilling and withdrawing the ordinary drill rod and the drill bit;

[0031] b. screwing the drill bit 2 into the front part of the rod body 1 of the reaming and self-rotating anchor rod by means of the threads, placing the drill bit 2 into the hole, keeping the baffle pawls 11 of the drill bit in a closed state and keeping the connecting member 3 for connecting the anchor rod bolter with the rod body 1 in a level state so that the wedge at the tail part of the rod body 1 is right embedded in the connecting member 3, and then mounting the reaming and self-rotating anchor rod to the anchor rod bolter 6 via the connecting member 3;

[0032] c. starting the anchor rod bolter, driving the reaming and self-rotating anchor rod to advance quickly in the existing small hole 8 to accomplish reaming under the action of the rotation of the drill bit 2 on the front part of the reaming and self-rotating anchor rod and the pushing force applied by a worker, so that friction force is generated between the anchor rod body 1 and the coal seam 7; decreasing the drilling rate of the anchor rod bolter 6 when the reaming and self-rotating anchor rod has reached to the bottom of the preformed small hole 8 in the coal seam 7 judged from obvious advancing resistance, utilizing the drill bit 2 on the front part of the anchor rod to rotate the rod body 1 into the coal mass, wherein, since the shape knives 10 on the front part of the drill bit 2 are in middle positions, the powder produced during drilling can be discharged away from the head part of the rod body 1 through the spiral grooves 9 on the side surface of the drill bit 2, the annular protrusion 1-2 on the rod body 1 blocks powder flowing out from the hole and thereby the powder fills the clearance between the rod body 1 and the coal mass; shutting down the anchor rod bolter 6 when the exposed length of the anchor rod body 1 is 30 mm150 mm, and separating the connecting member 3 from the symmetric wedge 1-1 at the tail part of the rod body 1, wherein, since the self-rotation of the anchor rod, there is a force interaction between the connecting member 3 and the rod body 1, the rod body 1 ought to retreat by some distance together with the connecting member 3 when the connecting member 3 is separated from the rod body 1, but the strong springs 11-4 of the baffle pawls 11 on the drill bit 2 eject at this point and the high-strength baffle plates 11-3 are pushed open and extend out of the groove cavities 11-1 to block the rod body 1 from further retreating; then, fitting the tray 4 over the tail part of the rod body 1 and mounting the nut 5 on the tail part of the rod body 1 to fix the tray 4, and using the anchor rod bolter 6 to rotate the nut to accomplish primary pre-tightening of the anchor rod, so that the anchor rod is squeezed and embedded into the coal mass, and thereby the friction force between the anchor rod and the coal mass is increased, the anchor rod is anchored in the full length, and the installation of a complete set of anchor rod is accomplished;

[0033] d. at 1 h2 h after the anchor rod works, tightening up the nut 5 with a wrench for secondary pre-tightening, to prevent prestress relaxation of the anchor rod incurred by working of other anchor rods nearby;

[0034] e. at 1224 h after the anchor rod works, checking the pre-tightening force on the anchor rod with a torque-indicating wrench, and pre-tightening up the anchor rod again if the pre-tightening force doesn't meet the requirement, so that the tray 4 squeezes the cracked coal wall to maintain the pre-tightening force;

[0035] f. repeating the steps ae for working of the next reaming and self-rotating anchor rod.