GRINDING TOOL

Abstract: Grinding tool having two circular rounds (10, 11) disposed on a spindle (15) and bobbins (26) distributed around the spindle, which are parallel to the spindle and span the distance between the rounds. On the bobbins, rods (23) are mounted which project from the periphery of the rounds. The bobbins and the rods mounted thereon are removably arranged between the rounds by the rounds being detachably interconnected on the spindle with a spacer (13) therebetween.

Description: GRINDING TOOL This invention relates to a grinding tool having two circular rounds disposed on a spindle, which are interconnected on the spindle with a spacer there¬ between, and rods distributed around the spindle, which are mounted between the rounds projecting from the periphery thereof for pivotal movement about axes which are parallel to the spindle. A grinding tool of this type is described in the international application PCT/SE79/00186 , several arrangements being proposed therein for allowing the rods to be exchanged not only to be replaced by new, identical rods, when they are worn down, but also so as to allow change between rods of different types and dimensions, so that the rods can be adapted to the work for which the grinding tool happens to be used. The purpose of the invention is to provide a further improved embodiment of the grinding tool of the type referred to above, further facilitating the handling of the rods and their mounting into the tool and their dismounting therefrom, and for this purpose the grinding tool has been given the characteristics appearing from claim 1. In order to illustrate the invention an embodi¬ ment thereof will be described in more detail below with reference to the accompanying drawings in which FIG. 1 is a perspective view of the grinding tool seen from the front end, FIG. 2 is an end view of the tool also seen from the front end, FIG. 3 is an axial sectional view of the tool , FIG. 4 is a perspective view of a bobbin with rods arranged thereon, and -^T k t; . {j V. -- 0 3 FIG. 5 is a perspective view of the tool, partly dismantled, illustrating the mounting of the bobbi ns i n the tool . The grinding tool shown in the drawings comprises two circular plastics rounds 10 and 11, the round 10 thereof having five smooth pins 12 which are integral with the round and project perpendicularly from one side thereof. The pins 12 thus arranged on the round 10 are uniformly distributed about the centre of the round. Moreover., the round 10 has at said one side a central cylindrical socket 13 projecting perpendicularly from said side and having five axial slots 14 which extend from the free end of the socket 13 nearly up to the round 10 and are uniformly distributed around the socket. A spindle 15 is threaded with a square portion 16 through a central square opening 17 in the round 11 and bears with a convex head 18 against one side of this round. With a threaded portion 19 the spindle is freely passed through a central aperture in the round 10, and a nut 20 is screwed onto the threaded portion. By the nut being tightened the rounds 10 and 11 can be clamped towards each other with the central socket 13 forming a spacer between the rounds, the free end of the socket 13 being received by a central circular cavity 21 in the round 11. Then, the spindle 15 is non-rotatably connected with the unit thus clamped on the spindle, by means of the square portion 16 received by the square aperture 17 in the round 11. The spindle has a projecting end portion 23 with which the grinding tool can be secured in a chuck on a drilling machine or other drive machine. A number of steel 'springs 23 with circular cross section are wound helically through some turns to form an eye 24 from which a shorter end portion 25 of the steel spring projects. The steel springs are passed with the eye 24 onto a tubular bobbin 26 the eyes having such a fit on the bobbin that the rods can pivot freely. The bobbin, which preferably consists of a cheap plastics material, has a fixed flange 27 at one end thereof while a flange 28 at the other end is made in the form of a head on a stopper 29 which is introduced into the tubular bobbin 26 and is held therein by means of a suitably formed snap lock or by the stopper 29 being held in the bobbin 26 by friction. In the embodiment shown an annular bead 30 is provided on the stopper 29 quite close to the flange or head 28 to snap into an annular groove, not shown, inside the bobbin 26 and so to hold the stopper 29 detachably in the bobbin. The bobbin 26 is dimensioned to be passed onto one of the pins 12 with the rods passed onto the bobbin, when the rounds 10- and 11 are separated, as shown in FIG. 5, a circular cavity 31 being provided in the round 10 about the pin 12 to receive the end flange 27. The projecting end portions 25 of the rods 23 are inserted into one of the slots 14 when the bobbin is being mounted. When the round 11 is then connected to the round 10, the end flange 28 will be received in a circular cavity 32 in the round 11. The bobbins thus mounted can be freely rotatable in the cavities 31 and 32 but they can also be fixedly clamped between the two rounds. Thus, it will be seen that the rods 23 are always received by the bobbin, at use as well as storage, and as a consequence there¬ of are easy to handle. The bobbin which should be made of plastics, considering the cost, will be heavily worn when the grinding tool is being used, if the. rods are ' .freely pivotable on the bobbin, but because the rods of the embodiment described can pivot to a limited extent only due to the engagement of the end portions 25 in the slots 14 this wear is considerably reduced such .that the bobbins can stand the total life of the rods In the embodiment shown the pins 12 extend over part of the axial length of the bobbins only but it is also possible to let them extend up to the round 11 with a portion having reduced diameter, said portion in that case passing through a central axial aperture in the stopper 29. Alternatively, a thinner pin can be provided on the round 11 and pass through the stopper 29 to meet the pin 12 when the rounds are interconnected. Moreover, it is possible to dispense with completely the pins 12 and retain the bobbins between the rounds exclusively by the end flanges 27 and 28 thereof being received by the cavities 31 and 32, respectively.

Claims: CLAIMS 1. Grinding tool having two circular rounds (10, 11) disposed on a spindle (15), which are interconnected on the spindle with a spacer (13) therebetween, and rods (23) distributed around the spindle, which are mounted between the rounds projecting from the periphery there¬ of for pivotal movement about axes which are parallel to the spindle, c h a r a c t e r i z e d in that the rods (23) are arranged on bobbins (26) with retaining end flanges (27, 28), and that the bobbins are remov¬ ably arranged between the rounds (10, 11) and by the interconnection thereof are fixed in a position sub¬ stantially parallel to the spindle (15). 2. Grinding tool according to claim 1, c h a r a c t e i z e d in that one end flange (28) of the bobbin (26) is removable. 3. Grinding tool according to claim 1 or 2, c h a r a c t e i z e d in that the end flanges (27, 28) of the bobbins (26) are received by cavities (31, 32) in the rounds (10, 11). 4. Grinding tool according to any of claims 1 to 3, c h a r a c t e r i z e d in that at least one round (10) has a guide pin (12) to be inserted into the bobbin (26). 5. Grinding tool according to any of claims 1 to 4, c h a a c t e r i z e d in that the spacer com¬ prises a central socket (13) on one round (10), the free end of the socket being engagable with the other round (11). 6. Grinding tool according to claim 5, c h a r a c t e r i z e d in that the rods (23) con¬ sist of spring wire which is helically wound to form an eye (24) for mounting the rod on the bobbin (26), and that an end portion (25) of the rod, projecting from the eye, is received by an axial slot (14) in the central socket to limit the pivoting of the rod on the bobbin.

Inventors: HOLMBERG G
Applicants: HOLMBERG GOTE ESKIL YNGVE, HOLMBERG G
Application year: 1980
Main classification: B24D13
IPC codes: B24D13, B24D17