RING CUTTER FOR TUNNEL DRILLING IN ROCK

Abstract: Cutter ring for drilling tunnels in rock, comprising two substantially identical halves being clamped to a rotation body (2) with two pins (6) arranged diametrically opposed each other and protruding into corresponding shaped holes (9) in the cutter ring halves, which radially inwardly directed portions having dovetail form for clamping in corresponding dovetail groove in the rotation body (2), whereby the dovetail groove being established by an inclined surface in the rotation body and by a wedge formed clamping ring (4) which is tightened radially inwards by means of bolts (5), between the cutter ring (1) and a second inclined surface in the rotation body, where the cutter ring halves being arranged on the rotation body with gaps (3) between the halves and the gaps (3) being offset 90 DEG in relation to the pins (6).

Description: Ring cutter for tunnel drilling in rock s- The present invention is related to a ring cutter for tunnel drilling in rock, which cutter is secured to the rotation, body of the cutter ring with a dovetail shaped cross section. Tunnel drilling machines or full face machines .are 0 used with idle journalled ring cutters distributed on the surface of the cutter head, each ring thereby being exposed to strong wear as well as some deformation. Replacing such cutter rings in known embodiments, mean to dis antel the cutter to remove the cutter ring itself. Some known cutter rings comprise s several segments, which embodiment however are not practical in use of certain rock types. With present technique there complete rings are used which therefore lead to relative comprehensive and time consuming replacement work which for the operator also means heavy working. With the cutter rings according to the present invention a cutter ring in two parts is provided which also is suitable for practical use and additionally may be replaced within a very short time. This is achieved with the cutter ring according to the resent invention as defined with the features of the accompaning claims. In the drawing, Fig. 1 discloses an axial section of a cutter ring bearing and Fig. 2 discloses a side view of the bearing in Fig. 1. A rotation body 2 is journalled on a shaft 6 secured to the cutter head of the drilling machine. The outer circumference of * the rotation body 2 is provided with a dovetail groove which in one side is expanded to a key way. In the dow tail groove are arranged diametrically opposed, two radially inwardly protuding pins 6, adapted for receipt in corresponding holes in one cutter ring half 1. The holes 9 being arranged in the middle of the cutter ring halfs. By inserting the two cutter ring halfs 1 in the dovetail groove and with the pin 6 protuding into the hole 9, the cutter ring halfs 1 may be displaced axially by a corresponding shape of the holes 9 in such a way that the cutter ring halfs 1 may abut against the one half of the dovetail groove in the rotation body 2. Between the cutter ring halfs 1 two gaps 3 with a dimention between 1,5 and 8 mm, preferably between 2 and 4 mm are provided. The gaps 3 have such a size that the cutter ring halfs 1 can be manufactured by simple cutting of a complete cutter ring and the gap thereby is not that large that detrimental strokes .will occure on the edge which is well known to be the case by larger gaps. On the other hand the gaps enable the cutter ring 1 to be deformed to a certain degree without closing the gap and thereby incurring internal stress. The cutter ring halfs 1 are secured to the rotation body 2 by clamping rings 4 comprising two equal halfs where the divition 8 between the two halfs preferably are offset 30° in relation to the gaps 3. The clamping ring 4 preferably has a wedge shaped cross section where one of the side surfaces is abutting against the cutter ring 1 and the other surface is abutting against a corresponding inclined surface in the rotation body 2. o The cutter ring is secured to the rotation body 2 by bolts 5 in axial planes 7 being offset 60° in relation to each other, with one of the planes 7 in the gaps 3. By tightening of the bolt 5, the cutter ring 1 is pressed against one of the inclined surfaces of the dovetail 5 groove in the rotation body 2, thereby secured with sufficient force. The two pins 6 • ensures that the cutter ring 1 will not rotate in relation to the rotation body 2 and the clamping ring 4. 0 This mantling and assembling of a new cutter ring 1 is made very easy by removing the bolts 5 and the two halfs of the clamping ring 4. Thereafter the cutter ring halfs 1 easily can be replaced and the two halfs of the clamping ring are again tightened by the bolts 5 with a force large enough to fix 5 the cutter ring 1 to the rotation body 2.

Claims: P a t e n t C l a i m s 1. Cutter ring for drilling tunnels in rock, 5 comprising two substantially identical halfs being clamped to a rotation body (2) with two pins (6) arranged diametrically opposed each other and protuding into corresponding shaped holes (9) in the cutter ring halfs, which radially inwardly directed portions having, dowtail form for clamping in o corresponding dovetail groove in the rotation body (2), whereby the dovetail groove being established by an inclined surface in the rotation body and by a wedge formed clamping ring (4) which is tightened radially inwards by means of bolts (5), between the cutter ring (1) and a second inclined surface in the s rotation body, CHARACTERIZED IN the cutter ring halfs being arranged on the rotation body with gaps (3) between the halfs and the gaps (3) being offset 90 β in relation to the pins (6). 2. Cutter ring according to claim 1, CHARACTERIZED IN the surface (8) of the clamping ring being offset 30° in o relation to the gaps (3) of the cutter ring. 3. Cutter ring according to claim 1-2, CHARACTERIZED IN the clamping ring (4) being secured by means of six bolts (5) arranged in three axial planes (7) being offset 60" in relation to each other, whereby one plane is arranged in the 5 gaps (3) . 4. Cutter ring according to claims 1-3, CHARACTERIZED IN the gaps (3) having a dimentioned of between 1,5 and 8 nun, preferably between 2 and 4 mm. 0 5

Inventors: NARVESTAD STEIN, NARVESTAD, STEIN
Applicants: STEIN NARVESTAD AS, STEIN NARVESTAD A/S
Application year: 1990
Main classification: E21C25
IPC codes: E21B10, E21D9