GB2043502A

GB2043502A - Rod grinding apparatus

Info

Publication number: GB2043502A
Application number: GB7907881A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1979-03-06
Filing date: 1979-03-06
Publication date: 1980-10-08
Also published as: GB2043502B

Abstract

A rod grinding apparatus particularly for grinding the tips of tungsten welding rods in which grinding members 47 are driven by means of a planetary gear system 33-37 and the rod is mounted in the chuck 12, the chuck being mounted so as to not rotate but being mounted so as to allow resilient movement of the chuck axially backwardly when an axial force is applied to the chuck and means 22 for limiting the forward movement of the chuck, whereby the resilient movement will allow the rod held in the chuck to be fed to the grinding members and the means for limiting the forward movement of the chuck will limit the amount of grinding carried out. <IMAGE>

Description

SPECIFICATION Mechanical tungsten rod sharpener The present invention relates to rod grinding apparatus.

Problems have arisen in grinding a suitable tip on tungsten rods, in particular in grinding a suitable tip on tungsten welding rods. If these are to be operated most efficiently then the point of the rod should be a specific shape and it is necessary from time to time to sharpen these rods as they are burnt away.

The apparatus to do so should be simple and rugged and require the minimum of supervision.

The present invention provides a rod grinding apparatus including means for mounting a rod comprising a chuck, chuck mounting means including means for preventing rotation of the chuck, means for allowing resilient movement of the chuck axially backwardly when an axial force is applied to the chuck, and means for limiting the forward movement of the chuck.

The means for preventing rotation of the chuck may comprise a slide of non-circular cross section mounted in a stationary slide mount of similar cross section. The slide is preferably of channel cross section.

The means for limiting forward movement of the chuck may comprise means for limiting relative movement of the slide and slide mount and may comprise a block member mounted on the slide to engage the rear of the slide mount. The block is preferably adjustably mounted to the slide by means of screw fixings.

The chuck is preferably mounted on a support member and the means for allowing resilient movement of the chuck axially backwardly may comprise a resilient means acting between the support member and a stationary mount. The resilient means is preferably in the form of a coil spring which may act between a collar on the support member and the stationary mount.

There may be provided a plurality of grinding members mounted to rotate in planetary fashion around the axis of the chuck, the grinding members being conical and of carborundum or abrasive stone. The grinding members are preferably rotated by planetary gears.

There will thus be described as a preferred embodiment of the invention an apparatus which is particularly rugged and simple to operate. Inserting the welding rod into the chuck is all that is required since the resilient mounting will automatically feed the welding rod towards the grinding members and the means for stopping this forward movement will limit the amount of forward movement and hence will stop the grinding operation when the welding rod has been ground to the right shape.

A preferred embodiment of the invention will now be described by way of example only and with reference to the accompanying drawings in which: Figure 1 is a general arrangement partly exploded of the preferred apparatus of the invention, Figures 2A and 2B show the planetary gear arrangement, Fig. 2A showing the ring gear and Fig. 2B showing the sun gear and planet gears, Figure 3 shows an enlargement of part of the apparatus of Fig. 1, for mounting the chuck, Figure 4 shows the grinding members, Figure 5 is a vertical longitudinal section through part of the apparatus for mounting the chuck, and, Figure 6 is an end view of the parts shown in Fig. 5.

The apparatus illustrated in these Figs.

which may be relatively portable so as to be usable on site comprises a base 10 of generally rectangular shape towards one end of which is mounted chuck mounting means 11.

The chuck is indicated at 12. The chuck is mounted on a hollow mounting bar 13 around which is mounted a collar 14 and as is more clearly illustrated in Fig. 3 the hollow bar 13 is rigidly connected by welding or other such means to a slide 16 of channel cross section ie a "U" cross section. The slide 16 is parallel to the bar 13 which in turn is coaxial with the chuck 12.

The slide 16 is mounted by means of a stationary slide mount 17 comprising a channel shaped member see Figs. 5 and 6 of similar cross section to the slide 16 whereby th slide 16 may slide along the channel section but is restrained from rotation and the slide mount inluding a top portion 18 to restrain removal of the slide 16 vertically. In this way the slide mount ensures that the slide 16 can only slide axially and suitable bearing surfaces on the slide and/or slide mount 17 may be provided to reduce the friction involved in this movement.

It is clear from the Figs. that the slide 16 projects from the backward end of the slide mount 17.

The slide mount 17 is mounted by means of a pillar 19 to the base 10.

Formed in the rearwardly extending portion 21 of the slide are a variety of marks 20 which are indicated more clearly in Fig. 3. A further channel section block member 22 is provided and may be slid on to the rearwardly extending portion 21 of the slide 16. The block 22 carries a screw 23 whereby the block 22 may be slid on to the rearwardly extending portion 21 of the slide 16 so that the front edge 25 of the block 22 abuts one of the marks 20, the screw is then tightened so that the block member 22 is rigidly clamped to the slide 16.The marks 20 along the side of the slide 16 include a first mark 20a which indicates the position to which the slide must be withdrawn when a rod is mounted in the chuck 12, and secondary marks 20b, c, d, etc which indicate the position to which the block 22 must be mounted which limits the forward movement of the slide 16, the marks 20 b,c,d, depending upon the diameter of the rod and being marked accordingly.

At the axial opposite end of the base 10 to the chuck mounting means 11 is mounted a power unit 31 which will generally be in the form of an electric motor. Mounted to the shaft of the electric motor 31 is a sun gear 32 which meshingly engages with three planetary gears 33, 34, 35 which in turn mesh with an internal ring gear 36. The ring gear 36 is mounted against rotation in a suitable bracket 37. It is arranged that the motor 31 and chuck 12 are coaxial.

Extending from the axis of each planetary gear 33, 34, 35 towards the chuck is a respective axle 38, 39, 40 these being mounted by means of bearings in a plate 42 which is mounted in a suitable bracket 43. To the protruding end of the axles 38, 39, 40 is mounted rods 44, 45, 46 and to the end of each of these rods 44, 45, 46 is mounted a respective grinding member 47, 48, 49 in the form of a carborundum or abrasive stone member.

In operation of the device, the chuck 12 is urged by means of the coil spring 15 acting between the collar 14 and the slide mount 17 forwardly towards the conical grinding members 47, 48, 49. This forward movement is restrained to an adjustable extent by means of the block 22.

The apparatus above described is operated as follows. The block 22 is set to the desired mark 20 which will depend upon the diameter of the rod being ground. The rod is mounted in the chuck and will of course extend backwards through the hollow mounting bar 13 and through the channel of the slide 16.

The slide 16 is withdrawn until the mark 20a is aligned with the rear of the slide mount 17.

The rod is slid forward until it is in contact with the grinding members 47, 48, 49. The mark 20a therefore provides an indication of the correct positioning of the rod for the commencement of the operation. The chuck is tightened to clamp the rod and the initial position of the rod is such that the spring 15 is under compression.

The motor 13 is then activated so as to rotate the sun gear 32 and hence the planetary gears 33, 34, 35. This causes the grinding members 47, 48, 49 to rotate both about the axis of the chuck and also about their own axes, the respective two rotations being in opposite directions. As the grinding members 44, 45, 46 rotate they grind the tip of the tungsten welding rod mounted in the chuck 12 and as the grinding proceeds the coil spring 15 feeds the rod in towards the grinding members 44, 45, 46. When the grinding operation is complete the block 22 will have moved into contact with the rear of the slide mount 17 at which point the grinding operation will be complete.

It will be seen that the apparatus described is extremely rugged and can be used on site.

Furthermore, once the welding rod has been mounted in the apparatus correctly and the motor switched on the apparatus can be left so as to grind the welding rod automatically without further attention. The operator can, for example, continue welding with another welding rod whilst one welding rod is being ground. When the operation is finished no further forward movement of the welding rod takes place and so no further grinding will take place. If necessary an automatic switch can be provided under these conditions (perhaps sensitive to the torque exerted by the motor 31) so that the apparatus will switch itself off when grinding is completed.

Claims

1. A rod grinding apparatus including means for mounting a rod comprising a chuck, chuck mounting means including means for preventing rotation of the chuck, means for allowing resilient movement of the chuck axially backwardly when an axial force is applied to the chuck, and means for limiting the forward movement of the chuck.

2. Apparatus as claimed in claim 1 in which the means for preventing rotation of the chuck comprises a slide of non-circular cross section mounted in a stationary slide mount of similar cross section.

3. Apparatus as claimed in claim 2 in which the slide is of channel cross section.

4. Apparatus as claimed in claims 2 or 3 in which the means for limiting forward movement of the chuck comprises means for limiting relative movement of the slide and slide mount.

5. Apparatus as claimed in claim 4 in which the means for limiting relative movement of the slide and slide mount comprises a block member mounted on the slide to engage the rear of the slide mount.

6. Apparatus as claimed in claim 5 in which the block is adjustably mounted to the slide.

7. Apparatus as claimed in claim 6 in which the block is adjustably mounted to the slide by means of screw fixings.

8. Apparatus as claimed in any of claims 1 to 7 in which the chuck is mounted on a support member, and the means for allowing resilient movement of the chuck axially backwardly comprises a resilient means acting between the support member and a stationary mount.

9. Apparatus as claimed in claim 8 in which the resilient means comprise a coil spring.

10. Apparatus as claimed in claims 8 or 9 in which the resilient means acts between a collar on the support member and thestation- ary mount.

11. Apparatus as claimed in any of claims 1 to 10 further including a plurality of grinding members mounted to rotate in planetary fashion about the axis of the chuck.

12. Apparatus as claimed in claim 11 in which the grinding members are conical.

13. Apparatus as claimed in claim 11 or 12 in which the grinding members are of carborundum or abrasive stone.

14. Apparatus as claimed in any of claims 11 to 13 in which the grinding members are rotated by planetary gears.

15. Apparatus as claimed in claim 1 substantially as hereinbefore described with reference to the accompanying drawings.