GB1559968A - Grinding head - Google Patents

Description

(54) GRINDING HEAD (71) We, REINHOLD REILING and KARL REVILING both citizens of the Federal Republic of Germany, and both of D-7531 Kampfelbach-Ersingen, Grundeltorstrasse 9, Federal Republic bf Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates two an abrading, buffing, or grinding head, hereinafter referred to as a grinding head, of the kind adapted to carry. replaceably a sheet of abrasive material and to be detachably and drivingly connected to a portable rotary power unit, and is an improvement in or modification of the invention set forth in our Patent Number 1475979.

According to the present invention there is provided a grinding head of the kind adapted to carry replaceably an abrasive sheet and to be detachably and drivingly connected to a portable rotary power unit, said head comprising a circular dished support member having a convex outer face and a concave inner face; a shank having an inner end secured to and projecting centrally from the inner face of said support member, and having a screw-threaded inner end portion, and an outer end portion adapted to be detachably and drivingly connected to a portable rotary power unit; on said shank, a circular dished clamping member of smaller diameter than that of the support member and having an inner concave face facing the inner face of said support member, an outer convex face and a central hole through which said shank passes; a clamping nut on said screw-threaded portion of the shank and a cutting disc clamped between peripheral edge faces of the support member and the clamping member, the cutting disc being of greater diameter than the support member, and having a central hole through which the shank passes.

Preferably, the cutting disc is flexible, and the clamping action of said member is such as to cause the disc to flex and increase its stability.

An embodiment of the invention will now be described, by way of example, with refer ence to the accompanying diagrammatic drawings, in which: Fig. 1 is an exploded sectional view of a grinding head and a cutting disc according to the present invention1 and Fig. 2 is an assembled view corresponding to Fig. 1.

Referring to the drawings, the grinding .head shown corresponds to that shown and described in. Patent Number 1475979, except that the hard-paffding member and the sheet of abrasive material.are omitted, as these, and especially the latter are not required when the cutter blade is fitted. A detailed description of the grinding head is therefore unnecessary, and the various parts will simply be indicated by reference numerals.

2 indicates the support member, 3 its peripheral edge, 4 the spindle or shank, 5 the screw-threaded inner portion of the shank, and 6 the outer portion of the shank adapted to be detachably and drivingly connected to a portable rotary power unit. 7 indicates a cutting disc, 8 the clamping member, 9 the peripheral edge of the latter, and 10 the clamping nut.

The cutting disc 7 has a central hole through which the shank 4 passes, as shown in Fig. 2. Also as shown in Fig. 2, the cutting blade 7 is clamped between the peripheral edge 3 of the support member 2 and the peripheral edge 9 of the clamping member 8.

The cutting disc 7 is, of course, of greater diameter than the support member 2, and, as the latter is of greater diameter than the clamping member 8, the respective peripheral edges 3 and 9 of the members 2 and 8 abut the cutting disc 7 in radially spaced zones, as shown in Fig. 2.

Thus, when the blade 7 is flexible, and especially a known blade incorporating fib rous material, the nut 10 can be tightened sufficiently to cause the cutting disc 7 to flex slightly out of its plane or become slightly dished due to the radial spacing between the peripheral clamping edges 3 and 9. This results in the cutting disc 7 being surprisingly firmly gripped by the members 2 and 8, and also results in the cutting disc becoming stabilised or rigidified sufficiently to eliminate or reduce the tendency for such blades to flutter in use.

WHAT WE CLAIM IS: 1. A grinding head of the kind adapted to carry replaceably an abrasive sheet and to be detachably and drivingly connected to a portable rotary power unit, said head comprising a circular dished support member having a convex outer face and a concave inner face: a shank having an inner end secured to and projecting centrallyfrom the inner face of said support member, and having a screw-threaded inner end portion, and an outer end portion adapted to be detachably and drivingly connected to a portable rotary power unit; on said shank, a circular dished clamping member of smaller diameter than that of the support member and having an inner concave face facing the inner face of said support member, an outer convex face and a central hole through which said shank passes; a clamping nut on said screw-threaded portion of the shank; and a cutting disc clamped between peripheral edge faces of the support member and the clamping member, the cutting disc being of greater diameter than the support member, and having a central hole through which the shank passes.

2. A grinding head as claimed in Claim 1, in which the cutting disc is flexible, and the clamping action of the said members is such as to cause the disc to flex and increase its stability, so that, in use, any tendency for the disc to flutter is eliminated or reduced.

3. A grinding head and a cutting disc as claimed.in Claim 1 substantially as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. or reduce the tendency for such blades to flutter in use. WHAT WE CLAIM IS:

1. A grinding head of the kind adapted to carry replaceably an abrasive sheet and to be detachably and drivingly connected to a portable rotary power unit, said head comprising a circular dished support member having a convex outer face and a concave inner face: a shank having an inner end secured to and projecting centrallyfrom the inner face of said support member, and having a screw-threaded inner end portion, and an outer end portion adapted to be detachably and drivingly connected to a portable rotary power unit; on said shank, a circular dished clamping member of smaller diameter than that of the support member and having an inner concave face facing the inner face of said support member, an outer convex face and a central hole through which said shank passes; a clamping nut on said screw-threaded portion of the shank; and a cutting disc clamped between peripheral edge faces of the support member and the clamping member, the cutting disc being of greater diameter than the support member, and having a central hole through which the shank passes.

2. A grinding head as claimed in Claim 1, in which the cutting disc is flexible, and the clamping action of the said members is such as to cause the disc to flex and increase its stability, so that, in use, any tendency for the disc to flutter is eliminated or reduced.

3. A grinding head and a cutting disc as claimed.in Claim 1 substantially as hereinbefore described with reference to the accompanying drawings.