GB2246845A - Alignment or levelling apparatus and a method of alignment using the apparatus - Google Patents

Abstract

Apparatus for alignment or levelling of a piece of equipment e.g. a motor comprises a plurality of cell units X, Y, Z having pressure cell means 219 defined within seals 220 and acting between relatively moveable members, 201, 207 to generate a separating force to facilitate displacement of one or more said members in a direction substantially normal to the separating force by sliding of the seal with respect to one member. The apparatus further comprises one or more lateral displacement means 247 and a fluid pressure ram 211 for elevation of the item to be aligned or levelled. In one embodiment a bed plate 205 and thrust plate 241 are employed with the pressure cell units X, Y, Z being placed in between to facilitate accurate positioning/alignment of an item placed on the thrust plate. <IMAGE>

Description

Title: Alignment or levelling apparatus and a method of alignment using the apparatus DESCRIPTION The present invention relates to alignment or levelling apparatus and a method of alignment using the apparatus.

There are many occasions when it is necessary to accurately align two or more pieces of machinery, with a common example being the alignment of a motor output shaft with an item to be driven. The components involved can weigh several tons. Checking alignment is done using such as dial test indicators and physically manoeuvering one of the items relative to the other using such as lifting hoists, levers and chocks until such time as the required alignment is achieved. As such obtaining the desired accuracy of alignment can be particularly time consuming since the apparatus available do not readily facilitate small controlled movements. It is an aim of the present invention to overcome the above mentioned difficulties.

Accordingly, one aspect of the present invention provides alignment or levelling apparatus comprising a plurality of relatively moveable members, fluid pressure cell means to generate a separating force reducing friction between adjacent members to facilitate displacement of one or more said members in a direction substantially normal to the separating force by one or more controllable lateral displacement means and further fluid pressure rams for elevation of the item to be aligned or levelled. For the typical load levels envisaged hydraulic fluid pressure is employed although pneumatic fluid pressure may be an option for some applications.

According to one embodiment the plurality of relatively moveable members is made up of a stack of members comprising at least a base member and a top member, and conveniently one or more (preferably two) intermediate members. Preferably the pressure cell means comprises a plurality of cell units and preferably each unit comprises a plurality of chambers each defined by parts of adjacent members and within a flexible sealing member disposed between adjacent members. In a preferred embodiment a plurality of cells, say 3, are provided between adjacent pairs of members, and it is further preferred to have said plurality of cells between adjacent pairs of members in substantial alignment. This is convenient to facilitate the admission of hydraulic fluid to the respective aligned cells by way of a common port.More preferably a fluid pressure ram is provided for each of the pressure cell units and is carried by the top plate and in alignment with the cells between the adjacent plates so as to be fed from the common port. A stroke of the order of 6mm has been found sufficient for the rams. An alternative is to have each cell ported separately.

Preferred controllable lateral displacement means comprises a hydraulic piston and cylinder assembly secured with respect to one member and acting on another, say an adjacent member. Preferably two such assemblies are provided for movement in mutually perpendicular directions.

The member preferably takes the form of plates with controlled interconnection at least for convenience of pivotability to prevent the assembly collapsing.

Such interconnection may usefully limit the maximum separation of at least some of the plates whilst allowing required movement normal thereto for at least other plates.

In another embodiment one or more (preferably three) discrete cell units are employed. Each cell unit comprises two relatively moveable members provided with fluid pressure cell means to generate a separating force therebetween to reduce friction and thereby facilitate displacement of the members relative to one another in a direction normal to the separating force. Each cell unit has a fluid displaceable piston, preferably in fluid communication with said pressure cell means, for use in elevating the item to be levelled and/or aligned.

Such cell units are preferably disposed at spaced locations, preferably in a common plane, and preferably disposed between a bed plate and a thrust plate. The item to be levelled and/or aligned is placed on the thrust plate. Lateral displacement means is provided to determine the position of the thrust plate, and said means may comprise a plurality of positioning members engaging threadingly with one of the bed plate and thrust plate and cooperable with abutment means of the other of the thrust plate and bed plate, preferably the latter. The positioning members are disposed to make adjustments in two directions normal to one another.

Typically the thrust plate and bed plate will be rectangular and two positioning means are positioned along each side, one towards each corner. The bed plate conveniently has a mounting pad in each corner, or otherwise positioned to align with the feet and/or securing parts of the item being levelled/aligned and the positioning means is engageable with a side force of the mounting pad for positioning.

The respective pressure cell means are coupled to a pressure source by suitable interconnecting pipe work and utilising appropriate valving for pressurisation of one or more of the pressure cell means simultaneously or in sequence.

The present invention also provides a method of accurately positioning an item of equipment, eg.

aligning or levelling same, utilising the aforedescribed apparatus comprising interposing said apparatus between a mounting surface and the equipment, determining the degree of out of position, pressuring one of more of the pressure cells to facilitate either insertion of shims for height adjustment, or sideways adjustment utilising the lateral displacement means, de-pressuring and securing the equipment in place.

The present invention also provides a pressure cell unit for use in accurate positioning of a piece of equipment comprising two relatively moveable members, fluid pressure cell means to generate a separating force reducing friction between the members to facilitate displacement of the members relative to one another in a direction normal to the separating force, and a further fluid pressure ram for elevation of the item to be accurately positioned.

The present invention will now be described further by way of example only with reference to the accompanying drawings; in which: Figure 1 is a plan view of the apparatus according to the invention, Figure la is a section of one hydraulic ram and the associated pressure cells, Figure 2 is a cross-section on line XX of Figure 1, Figures 3 to 6 are plan views of the respective relatively moveable plates, Figures 7 and 8 are diagrammatic side and end views respectively showing use of the device in aligning a motor, Figure 9 is a schematic illustration of hydraulic control circuitry, Figure 10 is a perspective view of a bed plate, thrust plate and discrete cell units according to another embodiment of the invention, Figure 11 is a cross-section through one cell unit of Figure 10, Figure 12 is a circuit diagram for the embodiment of Figures 10 and 11, and Figure 13 is a side view showing application of the embodiment of Figures 10 to 12 to levelling of a motor.

Referring firstly to the drawings of Figures 1 to 9, there is shown an alignment or levelling device according to the invention comprising four super imposed plates in the form of a base plate 1 (Figure 3), intermediate plates 2 and 3 (Figures 4 and 5 respectively) and a top plate 4 (Figure 6). The top plate carries four integral hydraulic rams B, B1, C, C1 comprising body 20 and piston 22 whilst pressure cell chambers are disposed between adjacent plates in alignment with the hydraulic rams. The cells are defined by adjacent surfaces of the members and within an annular seal received at least in part in a respective seal groove D of one plate with the adjacent plate being plane at least over the area where it contacts the seal. Simple O-ring seals have been found satisfactorily.The arrangement is illustrated to larger scale in Figure la from which it will be seen that each hydraulic ram is aligned with the respective pressure cells and has a port 19 for supplying pressure to each of the pressure cells associated by way of common port 21.

Complimentary keys 100 and keyway 101 are provided between plates 1 and 2 to limit the movement to the direction of the arrow 24, whilst complimentary keys 103 and keyway 104 are provided between plates 2 and 3 in this instance to limit movement to direction of the arrow 25. The bolts, not illustrated, are preferably provided between plates 1 and 2 and 2 and 3 to allow desired lateral movement without undue separation.

Finally a connection pin A is provided between plates.3 and 4 to maintain substantial axial alignment.

Also shown is a controllable piston and cylinder assembly E with the cylinder body mounted to plate 1 and the piston El cooperating with thrust block 37 of plate 2 whereby pressurisation of the piston cylinder assembly E gives rise to movement of plate 2 relative to plate 1 in the direction of arrow 24. Plate 2 carries a piston and cylinder F, the piston of which co-operates with thrust block 39 of plate 3 thereby pressurisation of the piston cylinder assembly gives rise to movement of plate 3 in the direction of arrow 25 relative to plate 2.

Since plate 4 is coupled to plate 3 the movement transmitted to plates 2 and 3 is thereby simultaneously transmitted to plate 4. Each of the hydraulic rams is supplied with pressure from a separate port and the plane of a plate mounted on the hydraulic rams integral with the top plate can be tilted in the required directions.

Referring now to Figures 7 and 8, the axis of pin A of the device is positioned to coincide approximately with the centre of gravity of the item to be aligned or levelled. The motor sits on a thrust plate interposed between the motor feet and the motor bed plate this will usually be recessed to receive the alignment/levelling device. Simultaneous application of hydraulic pressure to rams C, C1 raises the rear of the machine and tilts the machine axis Y. Similarly, application of pressure to rams B, B1 raises the front of the motor and tilts or levels axis Y. With the weight of the motor supported by all four rams ie B, B1, C and C1, hydraulic pressure is generated in the area enclosed by seals D.

This pressure is produced due to the communication of the pressure areas with the rams by means of the holes drill through items 2, 3 and 4 and holes drilled in the base of the rams. This has the effect of producing a separating force between items 1, 2, 3 and 4 with a consequent reduction in the loading and hence the frictional resistance to sliding. Due to the elevation of the machine by means of rams B, B1, C and C1 a gap is produced between the underside of the thrust plate and the motor bed plate. This gap is available to insert packings or shims at the final alignment stage. With the device in its active state ie rams pressurised and providing the thrust plate is clear of the bed plate, nine movements are available to assist in the alignment of axis X and Y or as an aid to levelling and positioning an individual piece of equipment.The movements are (i) vertically up, (ii) vertically down, (iii) tilt axis clockwise, (iv) tilt axis counter clockwise, (v) rotation about the axis of pin A (item four rotates against item three when a force is applied at right angles to Y), (vi) horizontal movement forward along the direction of axis Y when hydraulic pressure is applied to cylinder E, (vii) horizontal movement backward along the direction of axis Y when hydraulic pressure is applied to cylinder E, (viii) horizontal movement forward at right angles to the direction of axis Y when hydraulic pressure is applied to cylinder F and (ix) horizontal movement backward at right angles to the direction of axis Y when hydraulic pressure is applied to cylinder F. Cylinders E and F would be double acting piston cylinder assemblies with the piston secured to the relevant thrust plate.

In the case of the illustrated ie electric motor, the axis X and Y can be brought into alignment by using the above movements. The conventional method of checking the axial alignment using dial test indicators as shown can be used. When the axes are verified as being aligned by the dial test indicators the gap is measured between the underside of the thrust plate and the motor bed plate and the correct thickness of packings are then prepared and the machine is raised slightly by the hydraulic rams B, B1, C and C1 just high enough to admit the packings or shims. The motor is then lowered onto the packings or shims by releasing pressure until the full weight of the motor rests on the bed plate. The holding down bolts can then be tightened down and the alignment checked again using the dial test indicators.The process can be quickly repeated in the event of any distortion of the bed plate on bolting down.

Finally referring to figure 9 and schematic fluid control diagram is shown with appropriate three way valves to control pressurisation of cylinders B, B1 or C and C1 from hand pump 31, by way of select valves 20, 27, 28. Valves 27 and 28 are three-way valves to incorporate load holding and cylinder movement prevention. The piston cylinder assemblies E and F are double acting and controlled from a pump 33 incorporating a four-way valve and by way of select valves 35, 37. Arrows X denote lines tot he pressure cells for friction reduction.

Reference is now made to Figures 10 to 13 which illustrate a further embodiment of the invention. In this embodiment discrete cell units are employed as illustrated in Figure 11. The cell units X, Y, Z each comprise a base 201 having three projections 203 for eliminating rocking relative to a bed plate 205 described further hereinafter. Located on the base 201 is a moveable housing 207 which itself accommodates in a bore 209 an axially moveable piston 211. The housing has a port 213 by which fluid pressure is admitted to a chamber one end of which is open to an end 215 of the piston 211 and which is also in communication with the base by way of bore 217 to a relieved portion 219 of the housing whose peripheral boundary is defined by a seal groove housing a seal 220 which contacts surface 221 of base 201.

The housing 207 has a peripheral flange 223 which is received with clearance between the base and an annular member 225 secured to the base to retain the housing captive with the base but free to move in a plane normal to the axis of piston 211 as indicated by arrow A. A spring 215 serves to centralise the housing relative to the base. Piston 211 is provided with a piston return spring 217 to urge it into its withdrawn position.

Referring to Figure 10, a bed plate 205, typically a fabrication, has mounting pads 233, four in the illustration, by which the item to be levelled/aligned is located - see threaded or clearance holes 235. The bed plate has holes 236 for securing it to a prepared mounting surface. The mounting pads present abutment faces 237 referred to further hereinafter. Shown on the bed plate at spaced positions are three cell units X, Y, Z. Constructed for positioning over the bed plate is a thrust plate 241 having openings 243 to accommodate fixings into holes 235 of the bed plate from the item to be levelled/aligned. The thrust plate has formations 245 (two to each corner in the illustration), which receive threadingly positioning screws 247 which are engageable with the faces 237.

When an item is to be mounted in alignment with another item, the bed plate is first secured in place and the three cell units located on the bed plate and connected to the fluid pressure circuitry. Pressure is provided from a pump 501 feeding to a 3-way valve 503 which operated to select operation of units X or units Y and Z. 504 is a pilot operated valve, normally closed and 506 is a three way valve to select raise/lower of units Y and Z. 507 are non-return valves. The thrust plate is placed over the bed pate and rests on the mounting pads. At this stage there is a small distance between it and the retracted cell units.

At this stage the holes in the thrust plate can be aligned with the holes in the bed plate by means of the positioning screws provided on each corner. Any rocking of the thrust plate due to unevenness in the mounting pads must be eliminated by shimming on top of the mounting pads 233.

The next step is to lower the motor/machine onto the thrust plate with the motor or machine holding down bolts placed loosely in position to roughly align the holes.

Dial test indicators 520, 521 are now attached to the half couplings and used to determine the vertical misalignment of the shafts to be aligned. (There are optional methods of determining the amount of shimming required below the motor feet at it to achieve vertical alignment but whichever method is employed this is catered for).

Pressure is now applied to hydraulic units "Y" and "Z" then hydraulic unit X which raises the trust plate clear of the mounting pads. The required thickness of shimming determined from the previous step can now be inserted between the mounting pads and the thrust plate.

Pressure is released from the hydraulic units allowing the full weight of the motor or machine to rest on the bed plate via the thrust plate and the holding down bolts are tightened.

The vertical alignment can now be checked using the dial test indicators. Repeat previous steps if required until vertical alignment is satisfactory.

Horizontal alignment is achieved as follows: The holding down bolts are slackened to allow horizontal movement in any direction.

Pressure is applied to hydraulic units "Y" and "Z" then hydraulic unit "X" until the thrust plate is just clear of the mounting pads.

With the three hydraulic unit activated the resistance to horizontal movement is very low due to the separating force produced in the area enclosed seal.

The horizontal alignment is achieved by means of the positioning screws on the thrust plate which allows movement in any direction in the horizonal plane.

During this operation the dial test indicators are used to measure the movement until the horizontal alignment is verified as correct.

Pressure is then released from the hydraulic units until the motor or machine sits firmly on the bed plate with the holding down bolts tightened.

A final check is made with the dial test indicators to check the all round alignment and if the alignment is correct within the specified limits the hydraulic units and indicators are removed.

In practice it is possible that minor adjustments would be required to either or both the horizontal and vertical alignment of the shafts. These adjustments would be quickly achieved however by simply repeating the steps above.

Claims (28)

1. Alignment or levelling apparatus comprising a plurality of relatively moveable members, fluid pressure cell means to generate a separating force reducing friction between adjacent members to facilitate displacement of one or more said members in a direction substantially normal to the separating force by one or more controllable lateral displacement means, and further fluid pressure rams for elevation of the item to be aligned or levelled.

2. Apparatus as claimed in claim 1 in which the plurality of relatively moveable members is made up of a stack of members comprising at least a base member and a top member.

3. Apparatus as claimed in claim 2 further comprising one or more intermediate members.

4. Apparatus as claimed in any one of claims 1, 2 or 3 in which the hydraulic pressure cell means comprises a plurality of cell units each having chambers defined by parts of adjacent ones of said plurality of relatively moveable members and within a flexible sealing member disposed between said adjacent members.

5. Apparatus as claimed in claim 4 in which said chambers are in fluid communication with one another.

6. Apparatus as claimed in claim 5 in which a fluid pressure ram is provided for each pressure cell unit and in fluid communication therewith.

7. Apparatus as claimed in any one of the preceding claims in which the controllable lateral displacement means comprises a hydraulic piston and cylinder assembly secured with respect to one member and acting on another member.

8. Apparatus as claimed in claim 7 in which said another member is an adjacent member.

9. Apparatus as claimed in claim 7 or 8 in which two piston and cylinder assemblies are provided to control movement in mutually perpendicular directions.

10. Apparatus as claimed in any one of the preceding claims further comprising means for limiting axial movement of the plurality of relatively moveable members.

11. Apparatus as claimed in claim 4 or any claim appendant thereto in which the plurality of relatively moveable members are common to the plurality of cell units.

12. Apparatus constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings of Figures 1 to 9.

13. Apparatus as claimed in claim 1 in which the fluid pressure cell means are part of discrete cell units.

14. Apparatus as claimed in claim 13 in which there are two relatively moveable members making up the fluid pressure cell means of each cell unit, and each cell unit has a fluid pressure ram.

15. Apparatus as claimed in claim 14 in which the fluid pressure ram is in fluid communication with the pressure cell means.

16. Apparatus as claimed in one of claims 13, 14 or 15 further comprising a bed plate and a thrust plate and wherein the cell units are positioned at spaced locations to act between the bed plate and thrust plate.

17. Apparatus as claimed in claim 16 in which the lateral displacement means act between the thrust plate and the bed plate.

18. Apparatus as claimed in claim 17 in which the lateral displacement means comprise thrust members acting in two mutually perpendicular planes.

19. Apparatus as claimed in any one of claims 13 to 18 in which the respective pressure cell units are coupled to a pressure source via valving for pressurisation of one or more of the pressure cell units simultaneously or in a sequence.

20. Apparatus as constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings of Figures 10 to 13.

21. A method of accurately positioning a piece of equipment to level or alignment utilising the apparatus of claims 1 to 12 or 13 to 20 comprising interposing said apparatus between a mounting surface and the equipment, determining the degree of out of position, pressuring one or more of the pressure cells to facilitate either insertion of shims for height adjustment, or sideways adjustment utilising the lateral displacement means, de-pressuring and securing the equipment in place.

22. A method of positioning equipment substantially as hereinbefore described with reference to the accompanying drawings.

23. A pressure cell unit for use in accurate positioning of a piece of equipment comprising two relatively moveable members, fluid pressure cell means to generate a separating force reducing friction between the members to facilitate displacement of members relative to one another in a direction normal to the separating force and a further fluid pressure ram for elevation of the item to be accurately positioned.

24. A pressure cell unit as claimed in claim 23 in which the fluid pressure ram is received slidably in a bore of one of the members.

25. A pressure cell unit as claimed in claim 23 or 24 in which the fluid pressure cell means and fluid pressure ram are in fluid communication.

26. A pressure cell means as claimed in any one of claims 23 to 25 in which the pressure cell means is formed between adjacent parts of the two members and within a flexible sealing member disposed between the two members.

27. A pressure cell unit as claimed in claim 26 in which the flexible sealing member permits relative sliding movement between the two members in said direction.

28. A pressure cell unit constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing of Figure 10.