US2004630A

US2004630A - Grinding disk

Info

Publication number: US2004630A
Application number: US718133A
Authority: US
Inventors: Krug Carl
Original assignee: Individual
Current assignee: Individual
Priority date: 1932-12-06
Filing date: 1934-03-30
Publication date: 1935-06-11
Anticipated expiration: 1952-06-11

Description

June 11, 1935. c. KRUG 2,004,630

GRINDING DISK Filed March so, 1934 Carl K709 mrvzw+c ra i; TT'

Patented June 11, 1935 GRING DISK Carl Krug, Frankfort-on-the-Main, Germany Application March 30, 1934, Serial No. 718,133 In Germany December 6, 1932 the periphery of the grinding disk, this strain rapidly decreases. It has now been recognized that an increase in the strength of the annular zone near the wall of the aperture very efiectively reduces the dangerous strains and leads to an equalization of the strain over the entire cross section of the grinding disk, so that the risk of fracture of the grinding disk is reduced.

With a view to increasing the tensile strength of the material of the grinding disk it has already been proposed to incorporate materials of different nature such as metal insertions or reinforcements in the annular zone. Also in one and the same grinding disk grinding materials of difierent qualities which vary in respect of the nature and magnitude of the grinding granules or the nature and quantity of the binder therefor have been employed without attaining the desired end.

According to the present invention the resistance of the annular zone near the wall of the aperture to the action of the centrifugal forces is augmented by increasing the tensile strength of the material of the grinding disc by an auxiliary treatment, which does not alter the basic structure of the grinding disk in this zone. This is effected for example in that near the wall of the aperture the grinding disk is provided with an additional binder for the grinding granules so that the grinding disk has the basic structure uniformly throughout and is subjected to the supplementary treatment only at the annular zone, i. e., near the wall of the aperture. This is best effected by impregnating and hardening of the disk in the vicinity of the wall of the aperture by means of a solution of artificial resin, which is available commercially under the registered trade-mark Bakelite.

This measure is directly permissible because the parts of the grinding disk near the wall of the aperture which are subjected to reinforcement are not employed for the grinding operation in view of the mechanical means serving for securing the disk on the grinding shaft, so that the auxiliary treatment thereof cannot detrimentally afiect the grinding operation.

The new efiect of the grinding disks produced in accordance with the invention is based on the fact that without detriment to the reliability of operation they can rotate far more rapidly than hitherto and thus afiord a higher output. 1n addition, as the high annular strain at the wall of the aperture is considerably reduced and the lower annular strain at the periphery of the grinding diskis correspondingly increased, an approximately uniform distribution of the strain over the cross section of the grinding disk is attained, which gives increased reliability.

Two embodiments of the invention are shown by way of example in the accompanying drawing, in which:

Fig. 1 shows a side view and Fig. 2 a, cross sectional view of a grinding disk which is adapted for use only on a correspondingly constructed grinding machine.

Fig. 3 shows a side view and Fig. 4 a cross sectional view of a grinding disk the wall adjacent the aperture of which is arranged to accommodate the flange fastening which is customarily provided on grinding machines.

In the embodiment according to Figs. 1 and 2, I is the grinding disk, 2 the annular zone which has been reinforced by impregnation with a solution of artificial resin (bakelite) and hardening,

ing disk which can be mounted between theflanges of existing machines without any alteration thereto in the same way as the ordinary commercial grinding disks. For this purpose the grinding disk I is recessed on both sides to the size of the annular zone 2 which is impregnated with artificial resin and hardened. In this

way recesses

5, 6 are obtained which accommodate the securing flanges. In this way the grinding disk is clamped solely at the point of increased rigidity.

I claim:

1. A grinding wheel of uniform basic structure which has an arbor hole therethrough and which has an outer zone and a relatively narrow inner annular zone adjacent the arbor hole to which has been added a strengthening material throughout the thickness of the wheel, the outer zone being unchanged.

2. A grinding wheel of uniform basic structure which has an arbor hole throughout and which has an outer zone and a relatively narrow inner annular zone adjacent the arbor hole impregnated throughout the thickness of the wheel with a strengthening material, the outer annular zone being unimpregnated and unchanged.

3. The grinding wheel as set forth in claim 2, in which the strengthening material is a synthetic resin.

4. The grinding wheel as set forth in claim 2, in which the strengthening material is a phenolic condensation product. 1

\ CARL KRUG.