Tool bracket

Abstract

 Mounting device for easily exchangeable fastening of a grinding disc , cutting disc or the like on the end of a machine axle, said mounting device including a hub (7) on the machine axle and a disc (16) that can be mounted from the free end of the hub, said disc being connected with or made up of a grinding disc, cutting disc, or the like machining means. Said disc have a central hole (1) from the edge of which protrusions (2) protrude inwards, and the hub has on the outside recesses (10) corresponding to the protrusions of the disc, which axial recesses transcend into peripheral blind grooves opposing the intended rotational direction so that the tool can be pushed onto the tool bracket axially and then be turned into the blind groves so that the protrusions of the tool come in contact with the end walls (15) of said blind groves for the transfer of turning forces from the hub to the grinding disc.
A grove (12) for an O-ring is arranged around the hub on the sides of the blind groves facing away from the free end of the hub, said grove as the O-ring partially overlapping the peripheral groves (11) so that of the groves on sides facing away from the free end of the hub only shelves (14) remain. The peripheral groves are somewhat wider than the thickness of the protrusions (2) so that this until abutting one or several of the shelves of the groves resilient bear on the O-ring.

Description

[0001] In order to make concrete floors level end even grinding machines are used provided with several grinding discs or pads to increase the machining speed. By having the separate discs rotate in different directions the turning forces influencing the grinding machine and resulting from the rotation of the discs can be balanced. A problem at the grinding is that the grinding in itself can result in unevenness and notches causing a need for further grinding, for instance this may be caused by a grinding disc remain standing on the same place while rotating or cutting into an upwards bulging area.

[0002] The object of the invention is to remedy the above problem and reduce the risk of cutting damages.

[0003] In accordance with the invention the above problem is solved with a tool bracket in accordance with claim 1 for an exchangeable mounting of grinding discs on machine axles. A further problem at known mounting devices for grinding discs is that the disc at the machining sometimes get stuck so hard that the forces required to undo them risk to damage mounting device as well as grinding machine.

[0004] Further characteristics and advantages of the invention are apparent from the subclaims and from the following description of the mounting of a grinding disc on a grinding machine axle with reference to the appended drawings. In the drawings figs. 1 and 2 show a grinding disc seen from above and from the side respectively, fig. 3 a fastening hub for the grinding disc seen from the side of the grinding disc, fig 4 the fastening hub from the side, fig 5 the fastening hub in a longitudinal section, figs 6 and 7 perspective views of the fastening hub, fig 8 a cross section of the hub and fig 9 an axial section of the hub.

[0005] The grinding disc has a centrally arranged hole 1 from the edge of which four triangular protrusions 2 project inwards. The protrusions are evenly spaced over the perimeter of the hole. Due to the protrusions the hole gets the shape of a cross with short broad arms of the same length. The protrusions 2 facing inwards are in their inwards facing corners 3 rounded. The grinding disc is further provided with grinding linings or blocks 5 and holes 6 extending all the way through for transport of grinding dust.

[0006] On the axle of the grinding machine a hub is fastened. The hub has in the outer end, facing the object that is to be grinded, axial recesses 10 corresponding to the protrusions 2 of the grinding disc and a diameter allowing the fitting of the grinding disc on the hub 1. The recesses 10 transcend after a short distance into peripheral groves 11, with a width that is larger than the thickness of the disc. All peripheral groves have the same direction in relation to their corresponding axial recesses and against the working direction of the disc. After the axial pushing of the disc over the hub the grinding disc can be turned with the protrusions 2 into the peripheral groves 11. The turning is continued until the protrusions contact the end walls 15 of the peripheral groves.

[0007] Inside of the peripheral groves (towards the machine axle) a grove 12 with part circular cross section is arranged in parallel with the peripheral groves and partly overlapping these. In this part circular grove an O-ring is placed extending partly into the peripheral groves. Between the peripheral groves and the grove for the O-ring a narrow shelf 14 remains that serve as a stop for the movement of the disc in the direction of towards the hub if the pressure on it should become so large that the O-ring yield. This means that the grinding disc with the protrusions in peripheral groves individually or jointly can yield with a maximum measure defined by the location of the shelf. A certain angling of the disc is also possible.

[0008] The friction between the grinding disc and the O-ring and between the O-ring and the hub will as a result of the compression of the O-ring and the resulting forces be enough to grip the disc in the turned in position.

[0009] The O-ring does not only serve as a locking of the disc but permit furthermore in particular a certain flexibility of the disc in axial direction as well as for inclination. This reduces the strain on disc as well as machine, and also reduces the risk of unevennesses in the ground surface.

[0010] By making the recess in the disk symmetric the disc can be mounted on disc holders that have the peripheral groves directed laterally either to the left or right. Furthermore the opening in the disc can be made rapidly and at low cost by punching. The recess can be punched in the grinding disc itself and no separate bracket need to be riveted to the disc. If desired, one can furthermore make the discs two-sided with the same profile for the recess in the disc.

[0011] In the shown embodiment the number of protrusions on the disc is four but three as well as more than four can be considered.

[0012] Not only the disc is simple to fabricate but also the hub on the machine axle can be made comparatively simple since machining is only required on the outside.

[0013] If more flexibility than that provided by the O-ring is desired an additional O-ring may be mounted between the disc-holder and the driving axle in a concentric grove 15 in either of the each other facing surfaces of the fastening hub or the driving axle.

[0014] In order to facilitate the mounting of the disc the recesses 10 may laterally be chamfered 17 at the connection to the peripheral groves.

[0015] The invention enables a rapid and easily handled change without tools in particular for grinding machines for floors without the use of particular left and right rotating discs but the same discs can be used but with hubs with differently directed groves in the hubs. The invention can also be used at other types of grinding machines, angle grinders, saw blades etc. Since the recess in the disc can punched out and the disc holder only have to be machined on the outside production can be very rational. There is no risk that the discs will get stuck fast, a more even surface is ensured with the invention.

[0016] Practical tests have shown that the grinding discs are efficiently held by the O-ring with entirely straight groves 11. If so desired due to rules or for appearance sake the edge of the peripheral edge closest to the outer end of the hub and the axial recesses can be given a gently rounded threshold 9 protruding somewhat in relation to the rest of this edge. The groves 11 are sufficiently long for the protrusions to be turned past the thresholds.

[0017] Not only the disc is simple to fabricate but also the hub on the machine axle can be made comparatively simple since machining is only required on the outside.

[0018] If more flexibility than that provided by the O-ring is desired an additional O-ring may be mounted between the disc-holder and the driving axle in a concentric grove 15 in either of the each other facing surfaces of the fastening hub or the driving axle.

[0019] In order to facilitate the mounting of the disc the recesses 10 may laterally be chamfered 17 at the connection to the peripheral groves.

[0020] The invention enables a rapid and easily handled change without tools in particular for grinding machines for floors without the use of particular left and right rotating discs but the same discs can be used but with hubs with differently directed groves in the hubs. The invention can also be used at other types of grinding machines, angle grinders, saw blades etc. Since the recess in the disc can punched out and the disc holder only have to be machined on the outside production can be very rational. There is no risk that the discs will get stuck fast, a more even surface is ensured with the invention.

[0021] Practical tests have shown that the grinding discs are efficiently held by the O-ring with entirely straight groves 11. If so desired due to rules or for appearance sake the edge of the peripheral edge closest to the outer end of the hub and the axial recesses can be given a gently rounded threshold 9 protruding somewhat in relation to the rest of this edge. The groves 11 are sufficiently long for the protrusions to be turned past the thresholds.

Claims

1. Mounting device for the fastening of a grinding disc, cutting disc or the like on the end of a machine axle, characterized in

a) that it includes a hub (7) on the machine axle and a disc (16 ) mountable on said hub from a free end of the hub, said disc being connected with or made up of grinding, cutting discs, or the like machining means,

b) said disc having a central hole (1) from the edge of which protrusions protrude inwards and,

c) that the hub on the outside have axial recesses (10) corresponding to the protrusions of the disc,

d) which axial recesses transcend into peripherally directed blind grooves opposing the intended rotational direction so that the tool can be pushed onto the tool bracket axially and then be turned into the blind groves so that the protrusions of the tool are in contact with the end walls (15 of said blind groves for the transfer of turning forces from the machine axle to the tool,

e) that a grove (12) for an O-ring is arranged around the hub on the sides of the blind groves facing away from the free end of the hub, said grove partially overlapping the peripheral groves (11) so that of these on sides facing away from the free end of the hub only shelves (14) remain, and

f) that the peripheral groves are somewhat wider than the thickness of the protrusions (2) so that these until abutting one or several of the shelves of the groves resiliently bear on the O-ring.

2. Mounting device according to claim 1, characterized in

g) that the protrusions in peripheral direction in the disc are shorter than the blind groves extending peripherally in the hub and

h) that the groves on the wall that is closest to the free end of the hub in the part that is closest to respective axial recess bulge outwards from the free end of the hub forming thresholds for the protrusions of the disc when these are turned into the peripheral groves.

3. Mounting device according to claim 1, characterized in that at the transition from the axial recesses to the peripheral groves the inner bend is rounded (17).

Drawing