GB2249771A - Rotary station and seal therefor - Google Patents

Abstract

A rotary station comprises a rotatable table 4, Fig 1, carrying a plurality of pneumatically operated stations 12 to index them sequentially through operating positions 14. The air supply lines 18, for pneumatic control and operation of each station 12, are discrete to the respective operating positions 14 and so it is not necessary to supply a system of supply lines 18 which rotate with the stations 12. An end 20, Fig 1A, of a supply line 18 is sealed to a conduit 34 in the table 4 by a PTFE sealing member 24 which has an inwardly directed, tapered lip 32. As air pressure in the line 18 is increased (to operate the station) the lip 32 is urged against the underside 22 of the table 4. The operations effected may be soldering of electrical tags to an object with intermediate invertion of the object. <IMAGE>

Description

ROTARY STATION AND SEAL THEREFOR The present invention relates to a rotary station and to a seal, and in particular to a seal for a pneumatically operated rotary station.

In a rotary station a platform carrying one or more stations rotates about a central axis. Typically a station moves through several positions carrying a product being manufactured and the product is operated on at each position. Usually the operation performed at one position is the same for each station. The operations which may be required to be performed by each station are controlled pneumatically. In prior art systems, the air lines to the stations are fed through the central axis of the device. If different operations are to be performed by a station at two positions, the supply lines and/or control of the air supply are complex.

A first aspect of the invention provides a rotary station comprising a rotatable table having a plurality of pneumatically operated stations thereon, the table rotating the stations through a plurality of positions where different operations are performed, wherein an air supply line for operating a station at a particular position is discrete to that position.

By providing an air supply which is discrete to the position of operation it is possible to simplify the control of the stations and the air supply lines.

It is particularly preferred that the air supply be provided via the table, the table rotating above a supply line at a particular position and having a conduit which supplies air from the supply line to the station.

A second aspect of the invention provides a seal between an air supply line and a surface which moves relative to an end of the supply line, the seal comprising a flexible sealing member which encircles the end of the supply line and is arranged to flex outwardly to bear against the surface to form a seal between the end of the supply line and the surface when there is pressurised air in the supply line.

Other aspects, preferred features and advantages of the invention will be apparent from the following description and the accompanying claims.

The invention will be further described by way of example with reference to the accompanying drawings, in which: Figure 1 is a cross-section through a rotary station forming an embodiment of the invention, Figure la showing an enlarged cross-sectional detail of Figure 1 and illustrating a seal in accordance with the invention.

Referring to Figure 1, an embodiment of the invention comprises a rotary station 2, having a rotatable table 4 which is carried on a shaft 6 which is driven at its lower end (not shown) and is journalled in a tapered roller bearing 8 carried by a stationary support 10.

The table 4 carries four (three are shown) stations 12 which are fixed relative to the table 4 to rotate with the table 4 through four positions 14. The stations 12 are pneumatically operated.

By way of example, the sequence of operation on a product carried by a station would be: Position 1, place product on station Position 2, tin (solder) electrical tags on one side of the product Position 3, invert the product Position 4, tin (solder) electrical tags on the opposite side of the product Position 1, remove product, place new one in the station The tinning operation may, for example, require the station to move the product vertically or laterally, whilst the inverting operation requires a different operation. By providing at each position a supply line or lines 18 dedicated to the function performed at that position the construction of the supply lines 18 to the stations 12 and the control of the stations, which is pneumatic, is simplified.

An air supply line 18 is secured to the support 10 and has an open end 20 spaced a short distance from the underside 22 of the rotatable table 4. A polytetrafluoroethylene (PTFE) sealing member 24 surrounds the end 20 of the line 18. The member 24 comprises a sleeve portion 26 which is a snug fit around the end 20 of the line 18 and has a flange 28 at one end, which flange is held against a threaded rib 30 formed near the end of the line 18 by a nut 31. A radially inward annular lip 32 is formed at the other end of the sleeve 26. The lip 32 tapers in cross-section towards the axis of the sleeve, as is seen clearly in Figure la. The inner edge 35 of the lip 32 is spaced between about 0.04 and 0. 1 mm from the underside 22 of the table 4.

As the table 4 is indexed through ninety degrees, a conduit 34 comes into line with the open end 20 of the line 18. The conduit 34 connects with an air input 36 of the station 12 and has a smaller diameter than the inner edge 35 of the lip 32.

When the air is fed, under pressure, to the station 12, (at the position 14(a)), the lip 32 will be pressed outwards due to the air pressure and so bear against the surface 22 to form a seal between the line 18 and conduit 34. When the air pressure is released, at the end of an operation and before the table 4 is indexed through another position, the lip 32 will relax back away from the table 4, and so wear on the lip 32 is reduced.

Where a station has separate pneumatically operated controls, such as one for linear movement of a product and another to rotate a product, separate air control and hence separate conduits 34 will be provided in the table 34. Each conduit will mate with an air supply line 18 at a respective operating position, a conduit being unused if necessary.

Various modifications may be made to the described embodiment, and it is desired to include all such modifications as fall within the scope of the accompanying claims.

Claims (10)

1. A rotary station comprising a rotatable table having plurality of pneumatically operated stations thereon, the table rotating the stations through a plurality of positions where different operations are performed, wherein an air supply line for operating a station at a particular position is discrete to that postion.

2. A rotary station as claimed in claim 1, wherein the air supply line for controlling operation of a station at a particular position, connects with a conduit in the table.

3. A rotary station as claimed in claim 2, wherein the air supply line connects with the underside of the table.

4. A rotary station as claimed in claim 1, 2 or 3, wherein the air supply line is sealed to the table by means of a sealing member which is urged against the table, to form a seal between the line and table, by pressure of air in the supply line.

5. A rotary station substantially as hereinbefore described with reference to the accompanying drawings.

6. A seal between an air supply line and a surface which moves relative to the supply line, the seal comprising a flexible sealing member which encircles the end of the supply line and is arranged to flex outwardly to bear against the surface to form a seal between the end of the supply line and the surface when there is pressurised air in the supply line.

7. A seal as claimed in claim 6, wherein the sealing member comprises an annular lip which tapers towards its radially inner edge, the inner edge being urged axially outwards, against the surface, by the pressurised air.

8. A seal as claimed in 7, wherein the sealing member has a sleeve portion which is a snug fit around the end of the supply line.

9. A seal substantialy as hereinbefore described with reference to Figure la of the accompanying drawings.

10. A rotary station as defined in any one of claims 1 to 5, and including a seal as defined in any one of claim 6 to 9.