GB2224099A

GB2224099A - Alignment of shaft flanges

Info

Publication number: GB2224099A
Application number: GB8911064A
Authority: GB
Inventors: Stefan Norberg
Original assignee: Ovako Steel Couplings AB
Current assignee: Ovako Steel Couplings AB
Priority date: 1988-10-24
Filing date: 1989-05-15
Publication date: 1990-04-25
Anticipated expiration: 2009-05-15
Also published as: SE464485B; GB2224099B; GB8911064D0; SE8803794L; SE8803794D0

Abstract

When aligning heavy shafts, their flanges (4, 5) are first roughly aligned, after which an expander bolt (10) is inserted through the roughly aligned flange holes (16). The expander bolts have a conical core (6) and internally conical sleeves (1, 2) arranged axially separated from each other thereon. First the sleeves (1, 2) are inserted into the relevant flange (4, 5) to the plane (50) between the shaft flanges. Then the bolt core (6) is inserted through the sleeves (1, 2), the front end of the conical section (64) passing the join plane (20) between the sleeves (1, 2). In order to keep the nearest sleeve (1) at the join plane (50) when the bolt core (6) is being drawn, a space (8) is used which is placed on the drawn end of the bolt shaft (6) and has a head (86) located between a drawing device (7) fitted on the bolt shaft (6) and the exposed end surface (41) of the adjacent shaft flange. <IMAGE>

Description

DESCRIPTION OF INVENTION Alignment of shaft flanges The present invention relates to a device for aligning shaft flanges of the type revealed in the preamble to the independent means claim appended hereto. The invention also relates to a method of aligning shaft flanges of the type revealed in the preamble to the independent method claim. The invention also relates to the use of expander bolts for aligning shaft flanges with bolt holes, as described more fully in the application claim.

When aligning heavy shafts it is relatively easy to achieve a position in which the holes of the shaft flanges are substantially aligned, i.e. a position in which the alignment is only 1 - 2 mm off, for instance.

However, it is difficult and time-consuming to perform the final accurate alignment so that the flange holes are brought into perfect coaxial alignment.

The object of the invention is to offer a technique permitting relatively fast and simple alignment of shaft flanges with appropriate axial bolt holes in order to facilitate correct and faster alignment of shaft flanges.

According to the invention, a device of the type described in the appended independent claims is used.

Various embodiments of the device are described in the sub-claims defining the device.

The object of the invention is also achieved using a method as defined in the appended independent method claim, various embodiments being defined in the subclaims thereto.

The invention also relates to the use of expander bolts for aligning shaft flanges or the like, in accordance with the appended independent application claim.

The basic idea of the invention is that a rough alignment of the machine elements is carried out first, so that the holes therein are rougly aligned and are only displaced in relation to each other by at most about 1 - 2 mm, for instance. It may be shaft flanges that are being aligned or a machine stand which is being aligned to a foundation or the like. Expander bolts are then inserted in at least some of the roughly aligned machine element holes and the bolts are expanded, resulting in fine adjustment of the holes, and thus the machine elements. The expander bolts are suitably provided with an internally conical outer sleeve, dIvided nto two sections, which cooperates with a correspondinalv conical bolt core.The two sleeves forming the outer sleeve are inserted in respective bolt holes n each of the two machine elements, after which the core is passed through the sleeves so that the front part of the conical section of the core passes the join between the sleeves. The bolt coare is then drawn or pressed through the sleeves, thus aligning the sleeves, and thereby displacing the two machine elements so that their bolt holes are aligned.

The external shape and size of the sleeves may thus closely resemble the shape and size of the holes in the machine elements. The sleeves may thus be solid, and the pressure oil method can be used, for instance, when the core is to be removed from the sleeves. If the sleeves are to be expanded to any great extent, this can be done within the elastical region.

It should also be clear that axially slotted sleeves can also be used in order to permit particularly great expansion, i.e. when the rough alignment of the machine elements is relatively poor.

The bolt shaft may be provided with a coupling member, such as a tapped shaft portion at each end, in which case a drive means such as a nut-like, threaded hydraulic drawing means may be connected thereto and act against the adjacent flange surface via a tubular spacer supporting against the flange surface, its smaller end defining the position of the adjacent sleeve. It should thus be clear that the bolt core may be either pressed or drawn into the sleeves for alignment/expansion purposes.

It should also be clear that the preferred embodiment of the device need not necessarily be driven in order to effect substantial expansion of the outer diameter of the sleeves, and that therefore the expression "expander bolt" shall be interpreted as a construction comprising a sleeve which could expand but which does not necessarily expand upon performance of the invention.

The invention will be described schematically in the following, with reference to the accompanying drawing.

However, it should also be clear that the embodiment described by way of example is only a preferred embodiment and that the inventive concept is applicable in other functionally equivalent situations.

The single figure of the drawing shows in perspective an axial section through a part of the shaft flange joint.

The drawings thus show two heavy shaf , 15 aligned to each other by means of flanges 4, 5 provided with axial holes 16 distributed around the flange. The holes 16 are arranged to correspond with each of the two flanges and are thus coaxial when the shafts 14 and 15 are fully aligned with each other.

Using conventional means not shown here, the shafts 14, 15 can be roughly aligned to a position where the flanges 4, 5 are substantially adjacent and where the holes 16 in the flanges 4, 5 are only slightly displaced, by up to 1 - 2 mm. Expander bolts 10 (only one of which is shown in the drawing) are inserted in the roughly aligned flange holes 16 and then expanded to achieve perfect alignment of the holes 16 to each other. The expander bolts 10 comprise a bolt core 6 with a conical section 64 overbridging the join gap 50 between the flanges d, 5. Over the conical section 64 of the bolt core is a tubular element, conical on the inside and divided into two longitudinal portions or sleeves 1, 2, the join 20 between the portions 1, 2 lying in the same plane as the plane of the join 50 between the flanges 4, 5.The sleeves 1, 2 are provided with axial slits 3 permitting a considerable increase in the effective outer diater of the expander bolt 10 as defined by the external surface of the sleeves 1 and 2. Both the sleeves 1, 2 have conical inner surfaces with the same conicity as the central section 64 of the core, the external surfaces of the sleeves 1, 2 thus defining a cylinder.

The bolt core 6 is provided at each end with a tapped portion 73 extending out of each hole 16.

A tubular spacer 8 is provided with a head 86 and shaft 85, the shaft extending into the hole 16. The end 81 of the spacer shaft 85 abuts the end of the sleeve 1, and spacer head 86 has an end surface abutting the exposed end surface 41 of the shaft flange 4. The axial position of the sleeves 1, 2 is thus defined so that the join 20 between the sleeves 1, 2 and the join 50 between the flanges 4, 5 will lie in a common plane.

A drawing device 7 is screwed along a screw-thread 73 to the outer thread 63 on the bolt shaft 6 and abuts the head 86 of the spacer 8. The drawing device 7 is provided with a hydraulic chamber 72 with aially movable piston 74 which operates against the axially outer surface 84 of the spacer head 86. By introducing hydraulic fluid through the nipple 71, the chamber 72 can be pressurized so that the piston 74 rests against the outer surface 41 of the flange 4 via the spacer 8, thus positioning the spacer in relation to the surface 41. The shaft 6 of the expander bolt is thus drawn to the left in the drawing, thus expanding the sleeves 1, 2 radially. This expansion of the two sleeves 1, 2 will cause the flanges 4, 5 to be mutually displaced to achieve full coaxial alignment between the holes 16 without any shearing occuring in the sleeves 1, 2 since they are separate from each other. The bolt shaft 6 may be provided in conventional manner with a nipple 61 for pressure oil which is conveyed through a channel, not shown, to distribution grooves on the conical, central, outer surface 64 of the shaft in order to facilitate the axial relative displacement between the bolt shaft 6 and sleeves 1, 2 when the sleeves are solid, i.e. are not provided with axial slots 3 or the like.

Since the bolt shaft 6 is provided with a threaded portion 73 at each end, the expander bolt can easily be removed by removing the spacer 8 and hydraulic device 7 from the lefthand part of the core 6 as shown in the drawing. It can then be assembled on the righthand part of the shaft 6 as seen in the drawing, so that the core is drawn out of the sleeves when hydraulic fluid is forced into the nipple 71.

The drawing shows a joint between two shaft flanges, but it should be evident that the invention is also applicable to similar joints between other machine elements of similar type in which the basic problem is inherent.

A favourable embodiment of the invention entails both sleeves 1, 2 being first inserted into respective flange holes 16 up to the join plane 50. The core 6 is then passed through the sleeves 1, 2, at least far enough for the front end of the conical section 64 to pass the join 20, 50. The bolt core 6 can then be driven further in by suitable drive means. The embodiment just mentioned allows favourable use to be made of the conicity of the section 64. The sleeves 1, 2 may thus have an external diameter almost corresponding to the diameter of the holes 16 while still allowing the front part of the conical section of the bolt core to pass freely through the sleeves, past the plane 20, 50, so long as the diameter of the front end of the conical section is less than the smallest dimension of the remaining passage through the radially displaced sleeves at the join 20.

Since the sleeves 1, 2 themselves need not necessarily be expanded radially to any great extent, they may be solid and may even be deformed elastically. This permits practical use of the "pressure oil method", particularly when the expander bolt is to be removed.

The sleeves may preferably have an external diameter corresponding to the flange hole in which it is to be inserted and the internal surfaces of a pair of adjacent sleeves may preferably have the same diameter as the join plane.

Claims

C l a i m s

1. A device for aligning machine elements such as shaft flanges with the appropriate bolt holes, c o m p r i s i n g an expander bolt (10) insertable into the roughly aligned bolt holes of the machine elements.

2. A device as claimed in claim 1, w h e r e i n the expander bolt (10) has a core (6) with a conical section (64) and two axially separated sleeves, the inner surfaces of said sleeves corresponding in conicity to the conical section (64), and wherein each of the sleeves (1, 2) is placed in a machine element.

3. A device as claimed in claim 2, .^.- h e r e i n the expander bolt (10) is arranged to expand the sleeves (1, 2) by axial displacement of the bolt core (6) in relation to the sleeves (1, 2).

4. A device as claimed in any of claims 1 - 3, w h e r e i n the join (20) between the sleeves (1, 2) is located in the same plane as the join (50) between the flanges (4, 5).

5. A device as claimed in claims 3 - 4, w h e r e i n a drawing device (7) is arranged to support the exposed surface (41) of a shaft flange (4) and to displace the bolt core (6) by drawing it, wherein a tubular spacer (8) surrounding the bolt core (6) rests against the exposed surface (41) of the shaft flange (4) and extends into the flange hole (16) to provide supportive axial contact with the sleeve (1) therein and wherein the spacer (8) is loaded by the drawing device (7).

6. A device as claimed in claims 1 - 4, w h e r e i n the bolt core (6) and spacer (8) are arranged to cooperate with the drawing device (7) at one of the two ends (73) of the bolt core (73) in order to adjust or loosen the expander bolt (10).

7. A device as claimed in claims 1 - 6, w h e r e i n the sleeves (1, 2) are axially slotted.

8. A device as claimed in claims 1 - 6, w h e r e i n the bolt core (6) is provided with channesl (61, 62) to allow the insertion of pressure oil to the boundary surface between the conical section (64) of the core and the inner surfaces of the sleeves (1, 2).

9. A method of aligning machine elements such as shaft flanges (4, 5) with bolt holes (16), in which the shaft flanges are first roughly aligned, c o m p r i s i n g the insertion of expander bolts in the roughly aligned flange holes, said expander bolts having two axially separated sleeves (1, 2), placing the bolts with the join plane (20) between the sleeves in the join plane (50) between the shaft flanges (4, 5) and expanding the expander bolts.

10. A method as claimed in claim 9, c o m p r i s i n g the use of expander bolts having a bolt shaft with a conical section (64) and two separated sleeves (1, 2) arranged thereon, the inner conicity of the sleeves corresponding to the conical section (64) of the core.

11. A method as claimed in claim 10, c o m p r i s i n g first introducing the sleeves (1, 2) into bolt holes (16) in respective machine elements (4, 5) and then passing the bolt shaft (6) through the sleeves (1, 2) so that the conical section (64) passes the join (20) between the sleeves, and thereafter driving the shaft axially in order to achieve alignment.

12. The use of expander bolts with two internally conical sleeves (1, 2) arranged one after the other on a correspondingly conical bolt core (6) in order to align roughly aligned machine elements such as shaft flanges (4, 5) with appropriate bolt holes (16) by inserting the expander bolts into the roughly aligned bolt holes and driving the bolt core into the sleeves.

13. Any novel feature or combination of features disclosed herein.