GB2339160A

GB2339160A - Surface grinding of crockery

Info

Publication number: GB2339160A
Application number: GB9918280A
Authority: GB
Inventors: Gerold Sper
Original assignee: Maschinen und Stahlbau Julius Lippert GmbH and Co KG
Current assignee: Maschinen und Stahlbau Julius Lippert GmbH and Co KG
Priority date: 1999-05-12
Filing date: 1999-08-03
Publication date: 2000-01-19
Anticipated expiration: 2019-08-03
Also published as: GB2339160B; DE19921874B4; GB9918280D0; DE19921874A1

Description

2339160 Apparatus for the surface-grinding of flat crockery The invention

relates to an apparatus for the surface-grinding of flat crockery, in particular of plates made, for example, of bone china (BC) or of vitreous china (VC), on the underside and on the top side thereof.

Following the first firing operation, flat crockery, made in particular of BC or of VC, exhibits pitted elevations on its surface, i.e. on its underside and on its top side, these pitted elevations proving to be disadvantageous during subsequent decoration and glazing operations and/or resulting in rejects. These pitted elevations therefore have to be eliminated in order to prevent the abovementioned rejects. In order is to eliminate the pitted elevations, use has been made, up until now, of two grinding methods, namely barrelgrinding with so-called barrel- grinding machines or surface-brushing of the flat crockery. In the case of barrel-grinding, use is made of vibration drums or vibration pots in which there are located barrelgrinding bodies which are made to vibrate. The vibration of the barrel-grinding bodies brings the corresponding loose fill of the barrel-grinding bodies into a more or less random, i.e. undirected fluid state. The product flow remains undirected in this loose fill; automation of the grinding process is barely possible.

In the case of surface-brushing of the flat crockery, use is made of pairs of brushes comprising, for example, diamond-containing plastic brushes. The brushes of the respective pair of brushes are arranged such that they are in mutual engagement. This mutual engagement subjects the brushes to wear. The brushes 2 are associated with guide rollers on which the flat crockery, in particular plates, is/are supported during the grinding operation. The flat crockery which is to be ground is made to rotate by the rotating brushes.

For this purpose, it is, of course, necessary for the brushes to press with an appropriate grinding pressure against the flat crockery. This intensive contact of the brushes with the flat crockery further increases the abovementioned wear on the brushes. The service life of the brushes is thus limited. It is also the case that this brushing process is carried out manually, the underside and the top side of the flat crockery being brushed, i.e. ground at the same time. Hence the finish quality also leaves something to be desired.

In view of the above, the object of the invention is to provide an apparatus the use of which enables a good finish quality is achieved with a high rate of productivity.

This object is achieved according to the invention, by an apparatus apparatus for the surface grinding of flat crockery on the underside and on the top side thereof, wherein a first grinding arrangement is provided for the surface-grinding of the underside of the flat crockery, and a second grinding arrangement is provided for the surface-grinding of the top side of the flat crockery, the first and second grinding arrangements being spatially separated from one another, with the result that the underside and the top side of the flat crockery are ground independently of one another.

While it is known for the underside and the top side of the flat crockery to be ground at the same 3 time, the invention provides for the underside and the top side of the flat crockery, in particular plates, to be ground separately in terms of space and time.

In the case of the apparatus according to the invention, the first grinding arrangement may have at least one rotating brush. It is likewise possible for the first grinding arrangement to have at least one vibration pot with barrel-grinding bodies.

It has proven expedient if the first grinding arrangement has a first turntable with rotating vacuum suction devices by means of which the flat crockery which is to be ground is secured on its top side. In this case, the or each brush of the first grinding arrangement and the vacuum suction devices of the first is turntable are preferably driven such that mutually opposite tangential velocities occur on the respective contact surface between the brush and the flat crockery which is to be ground. It is thus possible for the brushing and/or grinding velocity to be increased correspondingly because the actual rotation of the respective vacuum suction device and thus the actual rotation of the flat crockery or plate is added, in respect of the grinding performance, to the rotary movement of the corresponding brush.

With the apparatus according to the invention it is advantageous if the first turntable is associated with a feed conveying arrangement for the flat crockery which is to be ground, in order to increase the degree of automation correspondingly. The same purpose, i.e. a further increase in productivity, is served if the rotating vacuum suction devices are provided in groups on the first turntable, because it is then possible for a plurality of plates to be simultaneously ground 4 optimally on their underside.

It is likewise possible for the rotating brushes of the first grinding arrangement to be provided in groups. In this case, it is possible for the rotating brushes of the various brush groups of the first grinding arrangement to have the same grinding properties, or-preferably different grinding properties, in order for it to be possible to carry out more or less a rough-grinding operation in a first operating step and a precision-grinding operation in a following operating step.

Preferably the second grinding arrangement has at least one rotating brush. In adaptation to the first grinding arrangement, the second grinding arrangement is may have a second turntable with rotating vacuum suction devices by means of which the flat crockery is secured on its underside. As has already been explained above in conjunction with the first grinding arrangement, the or each brush of the second grinding arrangement and the vacuum suction devices of the second turntable may be driven such that mutually opposite tangential velocities occur on the respective contact surface between the corresponding brush and the flat crockery which is to be ground, as a result of which the grinding velocity on the top side of the flat crockery is correspondingly high.

As on the first turntable, it is also possible for the rotating vacuum suction devices to be provided in groups on the second turntable. The same applies to the rotating brushes of the second grinding arrangement; these may expediently likewise be provided in groups. In order also to be able to carry out a rough-grinding operation and a precision-grinding operation on the top side of the flat crockery, it is possible for the rotating brushes of the various brush groups of the second grinding arrangement in the same way as the brush groups of the first grinding arrangement - to 5 have different grinding properties.

It is beneficial to the product flow and/or the product through-passage of the flat crockery which is to be ground if the first turntable and the second turntable are arranged one beside the other such that they overlap at a common transfer region. Such a design provides the advantage that the flat crockery, in particular plates, to be ground, can be transferred automatically from the first turntable onto the second turntable, in order for it to be possible for the top is side of the flat crockery to be ground once the underside of the flat crockery has been ground. Once the top side of the flat crockery has been ground, said crockery is removed from the second turntable at a removal position. Thereafter, the brushed and/or ground flat crockery may be, for example, decorated and glazed.

Further details, features and advantages can be gathered from the following description of an exemplary embodiment of the apparatus according to the invention for the surface-grinding of flat crockery, in particular plates, said exemplary embodiment being illustrated schematically in the drawing, in which:

Figure 1 shows a side view of the apparatus for the surface-grinding of flat crockery, in particular of plates, Figure 2 shows a plan view of the apparatus according to Figure 1, Figure 3 shows a detail of Figure I in order to 6 illustrate a section of the first grinding arrangement, Figure 4 shows an illustration, similar to Figure 3, of a second embodiment of the first grinding arrangement, and 5 Figure 5 shows an illustration, similar to Figure 3, of a section of the second grinding arrangement of the apparatus of Figures 1 and 2. Figures 1 and 2 show a schematic illustration of a design of the apparatus 10 for the surface-grinding of flat crockery, in particular of plates, on the underside and on the top side thereof. The apparatus 10 has a first grinding arrangement 12 for the surfacegrinding of the underside of the flat crockery and a second grinding arrangement 14 for the surface-grinding of the top side of the flat crockery. The first and the second grinding arrangements 12 and 14 are spatially separated from one another. The first grinding arrangement 12 has a first turntable 16 and the second grinding arrangement 14 has a second turntable 18.

The first turntable 16 is provided with rotating vacuum suction devices 20 by means of which the flat crockery which is to be ground is secured on its top side. As can be seen from Figure 2, the vacuum suction devices 20 are provided in groups, i.e. in this case in pairs, on the first turntable 16.

The first grinding arrangement 12 has brushes 22 which, as with the vacuum suction devices 20 of the first turntable 16, are provided in groups or in pairs. Each brush 22 is connected to a drive motor 24. Each vacuum suction device 20 of the first turntable 16 is connected to a drive 26. The brushes 22, which are for example inclined slightly in relation to the horizontal, and the vertical vacuum suction devices 20 7 of the first grinding arrangement 12 and of the first turntable 16, respectively, are driven such that mutually opposite tangential velocities occur on the contact surface (crockery underside) between the respective brush 22 and the flat crockery which is to be ground. This is indicated in Figure 1 by the arcuate arrows 28.

The first turntable 16 can be driven in rotation about a vertical axis 32 with the aid of a drive arrangement 30. It can be seen from Figure 2 that the first turntable 16 is associated with a feed conveying arrangement 34 with the aid of which flat crockery, in particular plates, to be ground is/are fed automatically in a stepwise manner to the apparatus 10 is and, with the aid of the first turntable 16, moved in a stepwise manner in relation to the brushes 22 of the first grinding arrangement 12. With the aid of the brushes 22, the underside of the flat crockery is ground over its entire surface. Following this grinding of the underside of the flat crockery the flat crockery is automatically transferred, at a common transfer region 36, from the first turntable 16 to the second turntable 18. In this case, the vacuum suction devices 20 of the first turntable 16 are deactivated and, at the same time vacuum suction devices 38 of the second turntable 18 are activated, i.e. have vacuum applied to them, in order to secure the plates which have been ground on the underside and, with the aid of brushes 40 of the second grinding arrangement 14, to abrade the surface of the top side of said plates. The brushes 40 of the second grinding arrangement 14 - as with the brushes 22 of the first grinding arrangement 12 - are connected to drive motors and provided in groups, i. e.

8 in pairs. Correspondingly, the vacuum suction devices 38 of the second turntable 18, which rotates in a stepwise manner about a vertical axis, are provided in groups or in pairs.

Following the grinding of the top side of the flat crockery, it is fed to a removal position 42 of the second turntable 18 and is there transferred from the second turntable 18 so that the ground flat crockery can be processed further. This further processing may involve the flat crockery being decorated and glazed. For this purpose, the second turntable IS is connected to a drive arrangement 44.

The first turntable 16 is moved in a stepwise manner, with the aid of its drive arrangement 30, in the direction of the arrow 46 and the second turntable 18 is moved in a stepwise manner, with the aid of the drive arrangement 44, in the direction of the arcuate arrow 48, the stepwise movements of the first and of the second turntables 16 and 18 being adapted to one another.

While Figures 3 and 5 illustrate designs of the grinding arrangements 12 and 14 with brushes 22 and 40, respectively, Figure 4 shows a first grinding arrangement 12 with vibration pots 50 in which barrel- grinding bodies 52 are located in a loose fill 54. During the vibration of the vibration pots 50 the barrel-grinding bodies 52 form a randomly moving fluid 56 which abrades the underside of the flat crockery 58. Such flat crockery 58 in the form of plates 60 can also be seen in Figures 3 and 5.

The same details are designated by the same designations in each case in Figures 1 to 5, so that there is no need for all the details to be described in 9 specific terms in each case in conjunction with the Figures.

List of designations:

Apparatus 12 First grinding arrangement (of 10) 14 Second grinding arrangement (of 10) 16 First turntable (of 10) 18 Second turntable (of 10) Vacuum suction devices (on 16) 22 Brush (of 12) 24 Drive motor (for 22) 26 Drive (for 20) 28 Arcuate arrow Drive arrangement (of 16) 32 Vertical axis (of 16) 34 Feed conveying arrangement (on 16) is 36 Transfer region (between 16 and 18) 38 Vacuum suction device (on 18) Brush (of 14) 42 Removal position (on 18) 44 Drive arrangement (of 18) 46 Arcuate arrow 48 Arcuate arrow Vibration pot 52 Barrel-grinding body (in 50) 54 Loose fill (in 50) 56 Fluid (of 54) 58 Flat crockery Plate 11

Claims

CIAIMS

1. Apparatus for the surface-grinding of flat crockery on the underside and on the top side thereof, wherein a first grinding arrangement is provided for the surface-grinding of the underside of the flat crockery, and a second grinding arrangement is provided for the surface-grinding of the top side of the flat crockery, the first and second grinding arrangements being spatially separated from one another, with the result that the underside and the top side of the flat crockery are ground independently of one another.

2. Apparatus according to Claim 1, wherein the first grinding arrangement includes at least one rotating brush.

3. Apparatus according to Claim 1, wherein the first grinding arrangement includes at least one vibration pot with barrel-grinding bodies.

4. Apparatus according to any one of Claims 1 to 3, wherein the first grinding arrangement has a first turntable with rotating vacuum suction devices for securing the top side of flat crockery which is to be ground.

5. Apparatus according to Claims 2 and 4, including means for driving the or each brush of the first grinding arrangement and the vacuum suction devices of the first turntable such that mutually opposite tangential velocities occur on the respective contact surface between the brush and the flat crockery which is to be ground.

6. Apparatus according to Claim 4, wherein the first turntable is associated with a feed conveying arrangement for the flat crockery which is to be ground.

12

7. Apparatus according to either of Claims 4 and 5, wherein the rotating vacuum suction devices are provided in groups on the first turntable.

8. Apparatus according to any one of Claims 1 to 7, wherein the rotating brushes of the first grinding arrangement are provided in groups.

9. Apparatus according to Claim 8, wherein the rotating brushes of the various brush groups of the first grinding arrangement have different grinding properties.

10. Apparatus according to any one of Claims 1 to 9, wherein the second grinding arrangement includes at least one rotating brush.

11. Apparatus according to any one of Claims 1 to is 10, wherein the second grinding arrangement includes a second turntable with rotating vacuum suction devices for securing the underside of flat crockery which is to be ground.

12. Apparatus according to Claims 10 and 11, including means for driving the or each brush of the second grinding arrangement and the vacuum suction devices of the second turntable such that mutually opposite tangential velocities occur on the respective contact surface between the brush and the flat crockery which is to be ground.

13. Apparatus according to either of Claims 11 and 12, wherein the rotating vacuum suction devices are provided in groups on the second turntable.

14. Apparatus according to claim 10, alone or together with any one of Claims 11 to 13, wherein the rotating brushes of the second grinding arrangement are provided in groups.

15. Apparatus according to Claim 14, wherein the 13 rotating brushes of the various brush groups of the second grinding arrangement have different grinding properties.

16. Apparatus according to one of Claims 4 and 10 together, or to any one of claims 11 to 15 in combination with both claims 4 and 10, wherein the first turntable and the second turntable are arranged one beside the other such that they overlap at a common transfer region.

17. Apparatus for the surface grinding of flat crockery, constructed and arranged substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.