WO2001075319A1

WO2001075319A1 - Shaft

Info

Publication number: WO2001075319A1
Application number: PCT/GB2001/001408
Authority: WO
Inventors: Sheila Hamilton; Charles Jonathan Kennet; William Crookston
Original assignee: Teknek Electronics Limited
Priority date: 2000-04-01
Filing date: 2001-03-30
Publication date: 2001-10-11
Also published as: GB0008044D0; AU2001244332A1

Abstract

There is described a hollow shaft (22) having drive means located within the shaft in the form of an air motor (28). Further there is described an air pressure supply system for securing correct operation of the shaft.

Description

Shaft

This invention relates to a shaft, and in particular to a shaft comprising internal drive means,- to a shaft comprising storage means for pressurised air; and to a shaft comprising pressure monitoring means.

A machine, such as a cleaning machine, often comprises a shaft that is normally driven to rotate by contact with a rotating roller. If the shaft is removed from contact with the rotating roller, its rotation slows and then stops. When the shaft is replaced in contact with the rotating roller, the inertia of the stationary shaft produces a drag force on the rotating roller with a detrimental effect on a wor piece in the machine.

From one aspect, the present invention provides a shaft comprising a hollow cylindrical body, and drive means disposed within said body. The exterior of said cylindrical body preferably is adapted for the releasable mounting of a hollow cylindrical core.

Typically, said drive means comprises a motor, preferably adapted to be driven by means of compressed air.

In one preferred arrangement, said motor is attached to a fixed spindle and to the cylindrical body and operates to rotate the cylindrical body.

From another aspect, the invention provides a shaft comprising a cylindrical body having storage means for pressurised air.

Preferably, the shaft further includes one or more inflatable elements on the exterior of the cylindrical body, and means for connecting said inflatable members with the pressurised air storage means.

The storage means may comprise a pressure chamber within the cylindrical body; and preferably comprises a first, operating, pressure chamber communicating with the inflatable elements; a second, reserve, pressure chamber adapted to store air at a pressure greater than that at which the first chamber is adapted to store air; and valve means interconnecting the first and second pressure chambers to supply air to the first pressure chamber when the pressure therein drops to a predetermined value .

A further aspect of the invention resides in a shaft comprising a cylindrical body, a drive spigot extending from one end of the cylindrical body, and air inlet means accommodated within the drive spigot .

Yet another aspect of the invention is provided by a shaft comprising a cylindrical body carrying at least one pneumatically actuated element, and pressure monitoring means for monitoring pneumatic pressure within the shaft.

Said pneumatically actuated element may comprise one or more inflatable elements on the exterior of the cylindrical body adapted for the releasable mounting of a hollow cylindrical core. Alternatively, or additionally, said pneumatically actuated element may comprise an air motor disposed within said cylindrical body for rotating the shaft.

Embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings in which:

Fig 1 is a schematic cross section of shaft means of a further aspect of the present invention comprising air storage means. Fig 2 is a schematic cross section of shaft means of an aspect of the present invention comprising drive means ;

Fig 3 is a schematic cross section of shaft means of a further aspect of the present invention comprising drive means ; and

Fig 4 is a schematic cross section of shaft means of a further aspect of the present invention comprising pressure checking means.

Referring to the Figures, a machine such as a cleaning machine comprises a roller set mounted on or adjacent the machine. The roller set comprises a first, working, roller and a second, back-up, roller.

The first roller is a cleaning roller. The first roller has a longitudinal axis and is mounted, by suitable bearings, for rotation about an axis aligned (as viewed from above) substantially on a radius of the machine centred on the machine's rotation axis. The periphery of the first roller is cylindrical or frusto-conical about its longitudinal axis.

The second roller is an adhesive roller. The second roller has a longitudinal axis and is mounted, by suitable bearings, for rotation about the axis aligned (as viewed from above) substantially on the same radius of the machine as the radius with which the first roller axis is aligned. The periphery of the second roller is cylindrical or frusto-conical about its longitudinal axis. The longitudinal axis of the second roller is such that, in use, the surface of the second roller periphery is in substantially uniform rolling contact with the surface of the periphery of the first roller.

The first roller comprises drive means and, in use, the second roller is normally rotated by rolling contact with the first roller.

The periphery of the first roller is coated or covered with an adhesive substance such as a silicone, suitable for cleaning a surface, such as the surface of a photolithographic mask for semi- conductor production. The adhesive surface of the roller has a tackiness which causes adherence to the roller of dust and other undesirable particulates on the upper surface of the mask when the roller is in rolling contact with the periphery of the first roller, thereby cleaning the upper surface of the mask.

The periphery of the second roller is coated or covered with a suitable adhesive substance such as a silicone.

The second roller is rotatably mounted for rotation about an axis in a manner allowing intermittent or continuous application of the second roller to the first roller with the peripheral surface of the second roller in rolling contact with the peripheral surface of the working roller during the application.

The adhesive substance on the periphery of the back- up roller has a degree of tackiness that exceeds the tackiness of the adhesive substance on the periphery of the working roller. Thus, dust and other particulates picked up by the first roller are transferred to the second roller by their mutual rolling contact. This transfer prevents a build up of particulates on the first roller with concomitant loss of cleaning effect.

The peripheral surface layer of the second roller is removable and replaceable when it becomes dirty.

The second roller comprises a shaft 2 substantially co-axial with said second roller, and adapted for fitment of a cardboard or plastic core (not shown) . The core is cylindrical or frusto-conical .

The shaft 2 comprises a plurality of radially projecting members in the form of bladder strips 4 which run substantially the length of the shaft 2, adapted for engagement with the core. The core is normally configured with channels or the like, shaped to accommodate the bladder strips 4.

The shaft 2 further comprises means to inflate the bladder strips 4 to engage the core, and to hold the core in place on the shaft 2. In the embodiments described, the bladder strips 4 are normally deflated. When there is a requirement to engage a core, the bladder strips 4 are inflated from a first deflated position to a second inflated or working position by means of compressed air. For this purpose, compressed air is supplied to the bladder strips 4 via the shaft 2. To maintain the bladder strips 4 in their working position during use of the second roller, there is a continuing requirement for the supply of compressed air.

Known shafts comprise a rotary air coupling at a first end of the shaft that couples the shaft to a permanent air supply. The air supply maintains sufficient pressure within the shaft to maintain inflation of the bladders to maintain engagement between the bladder strips and the core. This arrangement is bulky and clumsy and necessitates location of the machine adjacent air supply means.

The shaft 2 of the embodiment of Fig 1 comprises a pressure chamber that is adapted to be charged with air at or just above working pressure.

In this embodiment the shaft 2 comprises an operating pressure chamber 6 having bladder supply orifices 8 and an operating pressure valve 10. It further comprises a reserve pressure chamber 12 having a reserve pressure valve 14, and a regulated supply valve 16 linking the operating pressure chamber 6 and the reserve pressure chamber 12. The operating pressure chamber 6 is adapted to contain air at operating pressure of between 4.5 and 5.5 bar, the reserve pressure chamber 12 is adapted to contain air at the highest available pressure, probably of the order of 10 bar. For use, each chamber 6,12 is charged with air at the requisite pressure. The pressure in each chamber 6,12 is monitored by means of pressure gauges.

Passage of air between the reserve chamber 12 and the operating chamber 6 is regulated by the supply valve 16, which is normally closed. When the pressure in the operating chamber 6 falls below a pre-determined acceptable level, the supply valve 16 opens, and high-pressure air passes from the reserve chamber 12 into the operating chamber 6, increasing the air pressure therein.

Once the air in the operating chamber 6 reaches operating pressure, the supply valve 16 closes.

Operation of machine processes is not interrupted by recharging of the operating chamber 6.

In operation of the machine, the second roller is caused to rotate by contact with the first roller. The machine process is most efficient when both rollers are rotating at operating speed.

When particulates have accumulated on the second roller and its transfer ability is degraded to below an acceptable level, the second roller must be removed from engagement with the first roller for removal and replacement of the core in preparation for further dirt collection.

When removed from contact with the first roller, the second roller slows to a standstill.

The core of the now-stationary second roller can then be changed. For this purpose, the pressure in the shaft 2 is reduced by means of the operating pressure valve 10. This deflates the bladder strips 4 and releases the grip the strips 4 have on the core.

During the 'downtime' of the second roller, the reserve pressure chamber can be recharged from a separate air supply.

A suitable replacement core is then located on the shaft 2, and the bladder strips 4 are inflated either, in the above-described embodiment, by recharging the operating pressure chamber 6 to working pressure by introducing air from the reserve pressure chamber 12, or, in further embodiments yet to be described, by introducing pressurised air to the shaft via an air inlet from a separate air supply, to engage the core.

It is apparent that, if the machine continues to operate and the first roller to rotate during the interval when the second roller is removed from contact with the first roller, on replacing the second roller in contact with the rotating first roller, the inertia of the second roller will act as a brake, thus slowing the first roller with possible damage to the article currently being cleaned by contact with the first roller.

In a further embodiment shown in Fig 2 , to obviate this braking effect the shaft 22 is provided with internal drive means. This drive means is controllable by pressurised air.

The shaft 22 comprises a drive spigot 24 located on a bearing 26 at a first end of the shaft 22, and drive means in the form of a motor 28 adapted to be air driven. The motor 28 is accommodated within the shaft 22. The drive spigot 24 is fixed, and adapted to accommodate the motor 28 via a one-way clutch assembly 30. The shaft 22 is positioned on the drive spigot 24 to which the motor 28 is attached. The shaft 22 further comprises a pair of exhaust silencers 32.

The shaft 12 further comprises a rotary air coupling 34 mounted on a bearing 36 and connectable to an external air supply 38, and a pressure control valve 40. The air supply system is also in communication with the bladder strips 4. The control valve 40 operates to regulate the supply of pressurised air from the external air supply 38 both to the motor 28 and to the bladder strips 4. That is, in this embodiment, inflation of the bladder strips 4 is maintained by controlled supply of pressurised air from the external air supply 38.

The air supply system comprises a control system comprising platform electronics 42 and an electronically controlled pressure regulator 44, an air inlet 46 connected to a source of pressurised air at 6 bar via an air supply pipe 48, and the rotary air coupling 34 located on the bearing 36 at a second end of the shaft 22.

Pressurised air is directed from the external air supply to the pressure control valve 40 and thence to the bladder supply orifices 8 to inflate the bladder strips 4 and/or to the input of the air motor 28 to drive the air motor 28.

The purpose of the internal drive means is to bring the shaft 22 up to operating speed prior to its contact with the first roller. When it is necessary to drive the shaft 22, the control system operates to apply air of pressure greater than 5 bar to the inlet 46.

The air motor 28 is located on the fixed drive spigot 24. When air of sufficient pressure is supplied to the air motor 28, its location on the fixed spigot 24 prevents rotation of the motor 28. This produces a reaction force that rotates the shaft 22, and thus the second roller. Once the second roller reaches operating speed and is replaced in contact with the first roller, the pressure control valve 40 blocks the air supply to the motor 28, and the second roller is maintained at working speed by its engagement with the working roller.

The pressure control valve 40 also controls distribution of the pressurised air to the bladder strips 4. The pressurised air is supplied via a regulator control valve 50, and a non-return valve 52 that ensures uni -directional passage of air. The bladder strips 4 are also in communication with a quick release valve 54 that is operable to release pressurised air.

This arrangement further includes means to check the pressure of the air bladder strips 4. For the purpose of checking shaft pressure, air of pressure less than 4.5 bar is applied to the inlet. The shaft 22 can be checked, and the air supply topped up by the application of air at 4 bar at any time.

When no air is present the shaft 22 freewheels, and remains inflated.

In an alternative embodiment shown in Fig 3, the shaft 62 comprises a drive spigot 64 located on a bearing 66 at a first end of the shaft 62, and drive means in the form of a motor 68 adapted to be air driven. The motor 68 is accommodated within the shaft 62. The drive spigot 64 is fixed, and adapted to accommodate the motor via a one-way clutch assembly 70. The shaft 62 is positioned on the drive spigot 64 to which the motor 68 is attached. The shaft 62 further comprises a pair of exhaust silencers 72.

The drive spigot 24 further comprises entry means for an air supply system which supply system comprises a control system comprising platform electronics 74 and an electronically controlled pressure regulator 76, and an air inlet 78 connected to a source 80 of pressurised air at 6 bar via an air supply pipe 82.

The air supply means is connected to a pressure control valve 84 via a regulator valve 86. The regulator control valve 84 is also in communication with the bladder strips 4 via a non-return valve 88. That is, in this embodiment, inflation of the bladder strips 4 is maintained from the external air supply.

Pressurised air is directed from the external air supply to the pressure control valve 84 and thence to the bladder supply orifices 8 to inflate the bladder strips 4 and/or to the input of the air motor 68 to drive the air motor 68.

The purpose of the internal drive means is to bring the shaft 62 up to operating speed prior to its contact with the first roller. When it is necessary to drive the shaft 62, the control system operates to apply air of pressure greater than 5 bar to the inlet 78.

The air motor 68 is located on the fixed drive spigot 64. When air of sufficient pressure is supplied to the air motor 68, its location on the fixed spigot 64 prevents rotation of the motor 68. This produces a reaction force that rotates the shaft 62, and thus the second roller.

Once the second roller reaches operating speed and is replaced in contact with the first roller, the pressure control valve 84 blocks the air supply to the motor 68, and the second roller is maintained at working speed by its engagement with the first, working roller.

The pressure control valve 40 also controls distribution of the pressurised air to the bladder strips 4. The pressurised air is supplied via a regulator control valve 86, and a non-return valve 88 that ensures uni-directional passage of air. The bladder strips 4 are also in communication with a quick release valve 90, mounted on a bearing 92, that is operable to release pressurised air.

This arrangement further includes means to check the pressure of the air bladder strips 4. For the purpose of checking shaft pressure, air of pressure less than 4.5 bar is applied to the inlet. The shaft 62 can be checked, and the air supply topped up by the application of air at 4 bar at any time. When no air is present the shaft 62 freewheels and remains inflated.

The embodiment shown in Fig 4 illustrates a shaft 102 comprising air inlet means adapted to communicate, via a rotary air coupling 104 located on a bearing 106, with bladder supply orifices 8 via a non-return valve 108 to supply pressurised air from an external air supply 110 to bladder strips 4, to inflate the strips 4. In this embodiment the shaft is inflated normally. When the machine is in operation, the air is continuously under pressure. Due to the inclusion of the non-return valve 108, in the event that the air supply is lost, the shaft remains inflated. This arrangement is adapted to monitor the pressure of the bladder strips 4 during operation of the machine.

Improvements and modifications can be made to the above without departing from the scope of the invention.

Claims

1. A shaft comprising a hollow cylindrical body, and drive means disposed within said body.

2. A shaft according to claim 1, in which the exterior of said cylindrical body is adapted for the releasable mounting of a hollow cylindrical core.

3. A shaft according to claim 1 or claim 2, in which said drive means comprises a motor.

4. A shaft according to claim 3, in which said motor is adapted to be driven by means of compressed air.

5. A shaft according to claim 3 or claim 4, in which said motor is attached to a fixed spindle and to the cylindrical body and operates to rotate the cylindrical body.

6. A shaft comprising a cylindrical body having storage means for pressurised air.

7. A shaft according to claim 6, further including one or more inflatable elements on the exterior of the cylindrical body, and means for connecting said inflatable members with the pressurised air storage means.

8. A shaft according to claim 7, in which the storage means comprises a pressure chamber within the cylindrical body.

9. A shaft according to claim 8 in which said storage means comprises a first, operating, pressure chamber communicating with the inflatable elements; a second, reserve, pressure chamber adapted to store air at a pressure greater than that at which the first chamber is adapted to store air; and valve means interconnecting the first and second pressure chambers to supply air to the first pressure chamber when the pressure therein drops to a predetermined value.

10. A shaft comprising a cylindrical body, a drive spigot extending from one end of the cylindrical body, and air inlet means accommodated within the drive spigot.

11. A shaft comprising a cylindrical body carrying at least one pneumatically actuated element, and pressure monitoring means for monitoring pneumatic pressure within the shaft .

12. A shaft according to claim 11, in which said pneumatically actuated element comprises one or more inflatable elements on the exterior of the cylindrical body adapted for the releasable mounting of a hollow cylindrical core.

13. A shaft according to claim 11 or claim 12, in which said pneumatically actuated element comprises an air motor disposed within said cylindrical body for rotating the shaft.