Support for endless grinding sleeves

A support for endless grinding sleeves for grinding workpieces has a casing which axially running slots or grooves and the support has a round outline in cross section. An axial hole through the support becomes narrower along its length and is designed to receive a wedging cone that is to be drivingly joined with a shaft. The outer surface of the support is made somewhat smaller in size than the inner circumference of the endless grinding sleeve that is to be placed on the support and the cone is driven into the support to radially expand it into engagement with the sleeve.

FIELD AND BACKGROUND OF THE INVENTION 
The present invention relates to supports for endless grinding sleeves. 
In the prior art such supports have been designed for example in the form 
of grinding rolls or grinding porcupines. The casing of known grinding 
rolls or grinding porcupines is made of rubber-like rods or bristles 
forming the desired elastic connection between the grinding porcupine and 
the endless grinding sleeve. The rods extend radially outwardly and form 
the casing of the support. In this case the rods are all of the same size 
so that the casing part of the grinding porcupine is cylindrical. A 
shortcoming experienced with these known systems is that on pressing them 
against a workpiece the endless grinding sleeve is strongly bent and may 
be turned in relation to the roll in the circumferential direction. If 
there is such bending and twisting of the endless grinding sleeve, parts 
of the same are likely to be overstrained and in many cases this will be 
the cause of damage to the sleeve. Furthermore the endless grinding sleeve 
is likely to be damaged at the time it is being fixed in place on the 
grinding roll, because the outer diameter of the roll is always made a 
little smaller than the inner diameter of the endless grinding sleeve 
because of the production tolerances may not in all cases be completely 
realized. In the case of grinding rolls with a metal outer case the 
grinding outer face of the grinding sleeve is not elastic and giving 
enough in its properties. 
SUMMARY OF THE PRESENT INVENTION 
Taking this prior art as a starting point, one purpose or object of the 
present invention is that of designing a support or carrier of the sort 
noted hereinbefore so that there is no longer any trouble in positioning 
the endless grinding sleeve on the support. 
A still further purpose of the invention is to make certain that in such 
cases there is generally no chance of the sleeve being twisted in relation 
to the support. 
An even further purpose of the invention is to make certain that the sleeve 
generally speaking keep its form throughout its working life and when 
being used. 
Furthermore the sleeve of the invention is to be such that, as a base for 
the grinding sleeve, its properties are elastic enough. 
These and other purposes are effected in keeping with the present invention 
in that the support is made up of, an outer sleeve of foamed material or 
rubber with the endless grinding sleeve thereon, a cylindrical casing 
within the the outer sleeve, and a wedging cone which extends in the 
support. The casing of the support has at least one axially running slot 
or groove and a cross sectional outline of the support is round. A hole 
extends through the structure axially, and becomes narrower conically to 
receive the wedge cone, that may be keyed, that is to say 
torque-transmittingly joined, on a shaft or other support means, and 
furthermore the outer circumference of the support is a little smaller 
than an inner hole through the endless grinding sleeve to be fixed on the 
support. 
The useful effects produced by the invention are to be seen more specially 
in the simple way of placing or fixing the endless grinding sleeve on the 
support, more specially inasfar as it is possible in the invention for the 
outer surface of the support to be made with a smooth finish so that the 
sleeve may be slipped onto the support without any marked friction or 
resistance. A driving or keyed connection between the sleeve and the 
support is made possible at any time, even if the grinding sleeves, when 
mass produced, have some tolerance in size. This is because the outer 
circumference of the support may more or less always be changed somewhat 
as desired by the effect of the wedging cone and by the presence of a slot 
or groove in the casing of the support. In this respect however the outer 
form (that is round or cylindrical) of the support is not changed. A 
further useful effect to be experienced with the present invention is that 
the grinding sleeve as supported on the support is not changed while it is 
being used so that the work may be very accurately machined. In the case 
of the prior art it is not possible to be certain of the outer face of the 
grinding porcupine being completely round as desired because of the 
bristles being forced inwardly. 
Further useful effects of the invention will be seen from the claims. 
As part of one useful development of the present invention there are a 
number of slots or slits in the casing that may be placed parallel to the 
middle axis of the support, although it is furthermore possible for them 
to be helical. This design measure is a simple way of making certain that 
the outer surface of the support is in fact round, that is to say 
circular, and cylindrical even in those cases in which the radius of the 
support is increased by the effect of the wedging cone. A further useful 
effect produced by the slots is that the diameter of the support is 
increased in a simple way, more particularly inasfar as such increase is 
produced without any great force being needed. 
In keeping with a measure of the invention, which is of great value, the 
one end of the slots is freely open to the outside in the axial direction 
and the other end of the slots comes to an end within the casing, the open 
ends of each slot and the one next to it being at opposite ends of the 
casing. This part of the design makes possible not only an even radial 
distribution of the forces of the support acting on the sleeve, but 
furthermore there is the especially useful effect of an even axial 
distribution of these forces. 
As a further part of the invention the hole within the support is 
frusto-conical, the part of the wedging cone that is to be placed in the 
hole in the support having a form matching at least part of the hole into 
which it is to be fitted. The axial length of the wedging cone may be 
smaller than the axial length of the support. It is in this way that the 
invention makes use of the known effect of a frusto-conical wedge. 
There is a further useful development of the general idea of the invention 
wherein the casing part of the support is in the form of a prestressed 
sleeve made of rubber-like material, onto which the endless grinding 
sleeve may be fixed in place by friction. This part of the design makes 
certain that there is always the desired elastic joint between the 
grinding sleeve and the support, there being however a limited deformation 
of the grinding sleeve on machining the work, because the elasticity of a 
sleeve made of rubber-like material is made possible even if it is not 
very thick. In this respect it is best if the sleeve made of rubber-like 
material is somewhat chamfered at its top end so that it is then simpler 
for the grinding sleeve to be put in place. 
The support, in keeping with the present invention, will as a rule be 
joined up with a turning shaft. In this connection it is possible, as a 
useful part of the invention, for the wedging cone to have an axial hole 
therein into which the shaft may then be placed and joined up with the 
wedging cone. A connection between the wedging cone and the shaft may 
furthermore however be so produced by making the wedging cone with a stem 
running out axially from its thinner end and that may be with or without a 
screw thread. In the case of this design of the wedging cone the same may 
be directly screwed to the shaft. Lastly it is possible for the wedging 
cone to have a blind note at its thinner end so that the shaft may then be 
screwed into this hole. 
A detailed account will now be given of the invention using the working 
examples thereof to be seen in diagrammatic figures herein.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to the drawings in particular, the invention embodied in FIG. 7 
comprises a support 10 for an endless grinding sleeve 46. The support 10 
includes, as a major part thereof, a casing 12 which, in cross section, 
has a circular outer outline. The outer surface of casing 12 is 
cylindrical. Casing 12 includes a hole 20 therethrough which is 
frusto-conical. Hole 20 becomes narrower in the direction toward a shaft 
22 on which the support 10 also includes a wedging cone 24 which has a 
central hole 26 therethrough. Wedging cone 24 is received in hole 20 of 
casing 12 and is mounted on a journal 28 extending axially from shaft 22. 
Journal 28 extends through hole 26 of wedging cone 24. Wedging cone 24 is 
held on shaft 22, and urged into the frusto-conical hole 20 of support 12, 
by a screw 30 which is threaded into the journal 28. Screw 30, shaft 22 
and its journal 28 are shown in broken line in FIG. 7. 
As may be seen from FIGS. 3 to 5 the casing 12 has a number of slots 14, 16 
and 18 therein which extend parallel to the middle or central axis of the 
support 10. The one end 14', 16' and 18' of the slots 14, 16 and 18 in 
each case is axially open to the outside. The other ends 14", 16" and 18" 
come to an end blindly within the casing 12. The slots 14, 16 and 18 are 
so formed that the open ends 14', 16' and 18' of one slot and the slot 
next to it come to an end at opposite axial ends 32 and 34 of the casing 
12. 
In an alternate form shown in FIG. 6, the casing may include helical slots 
40 and 42. 
It is furthermore to be seen from FIG. 7 that the wedging cone 24, placed 
within the hole 20 of casing 12, has a form matching that of hole 20 in 
which it is fitted. 
In this respect the axial length d.sub.2 of part of wedging cone 24 which 
extends in hole 20, is smaller than the axial length d.sub.1 of the 
support 12. The support 12 has a prestressed sleeve 44 thereon made of 
rubber-like material, on which the endless grinding sleeve 46 is placed. 
The support 10 at its two axial ends 32 and 34, has larger diameter 
portions which form flanges or steps at 50 and 52 so that the elastic 
sleeve 44 may be permanently fixed to the support 10. 
The inside diameter of the grinding sleeve 46 is slightly larger than the 
outside diameter of the elastic sleeve 44 when the cone 24 is not fully 
seated, although this is shown in the figures. It is for this reason, that 
the grinding sleeve 45 is simpler to put on the support 10 or on the 
rubber sleeve 44. However, another way of making it simpler to put the 
grinding sleeve in place is for the top end of the sleeve 44 to be 
somewhat chamfered. 
In FIG. 2, another way will be seen of joining a wedging cone 24' to a 
driving shaft 23, and in this case, the thinner end of the wedging cone 
24' is pointing towards the end of a journal 29 of the driving shaft 23. 
The end of the journal 29 of the driving shaft 23 has a thread at 60. The 
wedging cone 24' is joined by way of a nut 62 with the driving shaft 
journal 29, such nut being placed in a hole 64 in the casing 12'. An axial 
wedging effect between the wedging cone 24' and the casing 12' is produced 
using a nut 68 so that the connection between the support 10 and the 
driving shaft 23 is not dependent on the axial wedging effect acting on 
the casing 12'. In FIG. 2, elements similar to those in FIG. 7 bear the 
same reference numerals but with primes. 
A further possible way of producing a connection between the wedging cone 
and the shft 23 is one in which the wedging cone has an axial stem or 
shank with a screw thread at its thinner end. By using this thread it is 
then possible for wedging cone to be done up using an axial hole in the 
driving shaft. Another possible form of connection between the wedging 
cone and the shaft is one in which the wedging cone has an axial blind 
hole with a female thread to take up a male-threaded driving shaft. 
A point always to be taken into account in connection with the design of 
the wedging cone is that its degree of taper is to be kept within a 
certain range. If the degree of taper is overly great, the wedging effect 
will not be great enough. In the opposite case, in which its degree of 
taper is not great enough the casing of the support and the wedging cone 
may become so strongly fixed together that there is a self-locking effect. 
It has been seen from experience that it is best if the point at which the 
base of the wedging cone is cut by the generatrix of the outer face of the 
wedging cone is such that the angle between the generatrix and the base is 
10.degree. to 30.degree.. A preferred angle is 20.degree.. 
In the design of FIG. 1 a wedging cone 70 is made of aluminum or synthetic 
resin with strips of cloth let into it and is made in one piece with a 
shaft 71. There is a nut 72 for connecting the grinding sleeve tightly to 
the support. The support has a casing 73 is in the form of a synthetic 
resin sleeve (or wedging sleeve) with slots running in from its two ends. 
There is furthermore a cylindrical outer sleeve 74 of foam material or of 
rubber-like material giving the desired elastic grinding effect. The 
endless grinding sleeve is marked 75.