GB2114029A

GB2114029A - Device for grinding and/or honing

Info

Publication number: GB2114029A
Application number: GB08300842A
Authority: GB
Inventors: Torgny Jansson
Original assignee: Tormek AB
Current assignee: Tormek AB
Priority date: 1982-01-15
Filing date: 1983-01-13
Publication date: 1983-08-17
Also published as: GB8300842D0; SE8200209L; DE3300954C2; SE436709B; GB2114029B; DE3300954A1

Abstract

A device for grinding and/or honing, for example of tools, comprises an electric motor (17) suspended in a stand (4) and pivotal about an axle (14) in parallel with but spaced from the motor shaft (19). A rotary disc (8), intended for grinding, honing or the like is located with a hub portion (7) on an axle (5) supported in the stand in parallel with but spaced from the motor shaft (19) and carrying axle (14), which hub portion (7) is provided with a driving surface (13) extending concentrically with the circumference of the disc and frictionally engaged by the shaft (19) whereby the disc is rotated for honing and/or grinding of a cutting tool. The other end of the shaft 5 may carry a grinding wheel 6, the lower part of which is located within a trough 10 of water. <IMAGE>

Description

SPECIFICATION Device for grinding and/or honing This invention relates to a device for grinding and/or honing, for example sharp-edged tools of various kinds.

At conventional devices of this type comprising a honing disc, the disc is mounted directly on the motor shaft. Due to the high motor speed, normally 3000 rpm, and the resulting high circumferential speed of the honing disc, it can be difficult to observe its direction of rotation. It can, therefore, happen that the edge of the tool to be honed unintentionally is turned against the rotation direction, which implies that the relatively soft material of the disc seizes the tool. Hereby not only the disc will be damaged, but there is also the risk that the operator will be injured. A further consequence of the high circumferential speed is that the edge to be honed easily is heated and annealed.These devices with high-speed discs, moreover, require contact and bursting protection, which in certain cases, for example at polishing operations, can be impeding and, in addition, render the device more expensive.

The aforesaid disadvantages are entirely eliminated by the present invention, as it is defined in the characterizing clauses of the attached claims.

It is possible by means of the invention to cause the honing disc to rotate at a low speed, for example 80 rpm, which implies easy observation of the rotation direction. The tool can be controlled without risk of accidents. The low speed implies that there is no risk of edge annealing, and on the same axle, on which the honing disc is mounted, also a grinding disc or a grindstone can be attached. These advantages are achieved by the favourable design of the reduction from the motor speed to the speed of the disc or discs. Thanks to the invention, a simple, reliable and silent speed gear acting by friction is obtained. Due to the fact that the end or ends of the motor shaft are countersunk in the hub portion of the disc, a very compact unit is obtained, and at the same time the motor shaft is protected by the honing disc and/or grindstone located outside.

The invention is described in greater detail in the following by way of an embodiment thereof, and with reference to the accompanying drawings, in which Fig. 1 is a lateral view of the device according to the invention, Fig. 2 is an end view of the device, where the honing disc partially is cut off for rendering the view clearer, Fig. 3 is a sectional view from above of the device, and Fig. 4 shows a detail of the device on a slightly enlarged scale.

1 designates a casing mounted on a base plate 2. The base plate, on which the device is supported, is provided with rests or feet 3. A bracket 4 with U-shaped cross-section is attached upwardly at the casing 1 and extends downward to the interior thereof. The bracket is provided with bearings, which freely rotatably carry an axle 5, which with its ends extends outside the casing. At one end of the axle a grinding wheel 6 is attached, and at the other end of the axle a hub portion 7 is mounted, on which a honing disc is attached, for example by means of screws with nuts 9. The grinding wheel and hub portion preferably are fixed by means of keyed joint (not shown) and nut, see Fig. 3. Beneath the grinding wheel 6 a trough 10 is provided, as shown, which is intended in normal manner to be filled with water when the grinding disc is in operation.The trough side facing to the casing has the form of a transverse wall 12, which in addition to serving as a hold for the trough on the casing also has the object to reinforce the casing. A support iron 11 is provided, as shown, to Facilitate the grinding of the tool.

As appears most clearly from Fig. 3, the hub portion 7 is provided about its circumference with a track or driving surface 13, for example of rubber, which will be described below. The honing disc 8 consists of an outer honing ring 8', which is heeled on a hub 8". As the radial portion of the hub 8" extends along the outer lateral plane of the honing disc and is attached on the outside of the hub portion 7, a space is obtained radially outside the track 13, but inside the inner lateral plane of the honing disc 8.

In the bracket 4, in parallel with the axle 5 a carrying axle 14 is mounted, which pivotally supports a carrying plate 15, which by means of bushings 16 is prevented from axial movement on the axle 14. On the lower surface of the carrying plate 15 (Fig. 2) an electric motor 17 is attached by means of, for example, bolts as indicated in Figs. 2 and 3. The motor can be connected to a current source via a cable 18. The motor shaft 19 extends free bearing outside the motor into the space between the track 13 and hub 8" and, due to the pivotal suspension of the motor 1 7 about the carrying axle 14, is pressed by the gravity against the track 13.As appears from Fig. 4, the free bearing motor shaft 19 extends in between the track and honing disc, thereby permitting the honing disc to be positioned closely adjacent the casing, whereby both the driving shaft 19 and the driving track 13 are protected, and the entire device can be designed with small width.

Due to the arrangement of the axles 5 and 14 relative to each other and to the motor shaft 9 in parallel with said axles, the motor shaft at its clockwise rotation shown in Fig. 2, for driving the honing disc and grindstone automatically is pressed against the driving track 13 when the grinding disc or honing disc is loaded. The friction between the axle 19 and track 13 thereby increases automatically.

As appears from the aforesaid, the present invention, thus, provides a built-in, simple and inexpensive drive gear between motor and grinding and, respectively, honing disc.

It is, of course, possible within the scope of the invention to design the grinding disc with a hub portion corresponding to the hub portion for the honing disc and to arrange the motor shaft extending so through the motor, that each end of the motor shaft engages with a driving surface 13.

The term honing disc is to be understood to comprise also emery wheel and the like.

Claims

1. A device for grinding and/or honing, comprising an electric motor (17), the motor shaft (19) of which has at least one free bearing end, characterized in that the motor ( 1 7) is suspended in a stand (14) pivotal about a carrying axle (14) in parallel with but spacedfrom the motor shaft 9), that in the case of one free bearing motor shaft end a rotary disc (6, 8) intended for grinding, honing or the like is located with a hub portion (7) on an axle (5) in parallel with but spaced from the motor shaft (1 9) and carrying axle (14), which hub portion (7) is provided with a driving surface (13) extending concentrically with the circumference of the disc and facing to the axle, and that the free bearing end of the motor shaft (1 9) with its outer surface abuts the driving surface (13).

2. A device as defined in claim 1, characterized in that the driving surface (1 3) is countersunk in the hub portion (7) inside of the planes defining the sides of the disc (6).

3. A device as defined in claim 1 or 2, characterized in that the driving surface (13) is provided with a friction-increasing coat.

4. A device as defined in any one of the preceding claims, characterized in that the carrying axle (14) is located to the side of the axle (5) and above the motor shaft (19), which engages with the driving surface (13) on the same side of a vertical plane through the axle (5) where the carrying axle (14) is located, and that the motor shaft (19) has a rotation direction, which at the braking of the axle (5) tends to pivot the motor about the carrying axle (14) in such a direction, that the motor shaft (19) is pressed against the driving surface (13).

5. A device as defined in any one of the preceding claims, characterized in that the axle (5) on one side of the motor supports a hub portion (7) with a honing disc (8) and on the other side of the motor a grinding disc (6).

6. A device as defined in claim 5, characterized in that the grinding disc also comprises a hub portion, and the motor shaft extends through the motor and is free bearing on each side thereof, and that the free ends of the motor shaft abut the driving surface of the respective hub portion.

7. A device for grinding and/or honing, substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.