GB2223560A

GB2223560A - Shaft coupling with alignment adjustment means

Info

Publication number: GB2223560A
Application number: GB8921157A
Authority: GB
Inventors: Charles C Heald; John P Gamlin
Original assignee: Ingersoll Rand Co
Current assignee: Ingersoll Rand Co
Priority date: 1988-10-04
Filing date: 1989-09-19
Publication date: 1990-04-11
Anticipated expiration: 2009-09-19
Also published as: IT1233011B; JPH02142923A; CA1316004C; JPH0587690B2; SE8903120L; CN1015565B; AU619045B2; AU4169889A; GB2223560B; FR2637336A1; SE8903120D0; CN1041642A; IT8921795A0; DE3933154A1; GB8921157D0

Description

SHAFT COUPLING WITH ALIGNMENT ADJUSTMENT MEANS This invention relates to a

coupling for rigidly interconnecting the shafts of rotating machinery in axial alignment and more particularly to a coupling having means for adjusting the axial alignment of a pair of axially aligned shafts interconnected by the coupling.

Two general types of couplings are used for interconnecting the shafts of rotating machinery. one type is known as a "flexible coupling". In using a flexible coupling, each piece of machinery includes a bearing support system that independently and completely supports its rotating shaft without.the need of additional support from outside of the machinery. The shafts of such machinery are interconnected by the flexible coupling that absorbs any misalignment of the shafts. The designers of such machinery attempt to position the machinery with the shafts in axial alignment but recognize that the machinery may not be in exact axial alignment or may move out of axial alignment after installation. Such misalignment is handled by the flexible coupling allowing the machinery to operate without the need for the shafts to be in perfect axial alignment.

The second type of coupling is known as a "rigid coupling". A rigid coupling is normally used in the situation where the bearing support system for one of the pieces of machinery is inadequate to support fully and independently the shaft of such machinery by itself and relies on the bearing support system of the interconnected piece of machinery. In using the rigid coupling, the two 2 pieces of machinery are connected together by a means such as a common support system which anchors the two pieces of machinery in fixed relationship relative to each other and the shafts are interconn_ected by the rigid coupling with the intention that they be in good axial alignment. However, the shafts are not always in perfect alignment and frequently much effort is expended to ensure that the shafts are in axial alignment and remain in such alignment during use of the machine.y. The alignment problems with a rigid coupling are more likely to arise as the distance between the interconnected machinery becomes greater. This invention relates to a rigid coupling.

An object of this invention is toprovide a rigid coupling is for rigidly interconnecting the rotating shafts of machinery together in axial alignment and including means for adjusting the axial alignment of such shafts when necessary and locking the shafts in the finally adjusted relative position to prevent them from moving out of such alignment position during operation.

Another object of the invention is to provide a shaft coupling of the rigid type which allows the end portion of one shaft to swivel in the coupling and contains plural adjustment members spaced around the end portion of the one shaft to move the end portion of the shaft to a swivelled position relative to the coupling and to the axis of the other shaft engaged in the coupling.

According to the present invention, there is provided a coupling for interconnecting two axially aligned shafts together for transmitting torque from one shaft to the 3 is other shaft, said coupling comprising an elongate cylindrical body having an axial bore therein extending over its length adapted to receive the adjacent ends of both shafts in substantial axial alignment, means fpr keying the ends of each shaft to the adjacent coupling body for transmitting torque between said shafts through said coupling body, fulcrum means on said coupling for firmly grasping one of said shafts at a point spaced from its end over a relatively short distance along the length of the coupling, the bore of said body being spaced from said fulcrum means and being substantially larger than the end of said one shaft whereby said one shaft can tilt along its length about the fulcrum means of said coupling allowing the axis of said one shaft to tilt to an inclined position relative to the axis of the coupling body and means in said coupling body for engaging the end of said one shaft and urging it to said inclined position relative to the axis of said coupling body for adjusting said one shaft relative to the coupling to change the relative axial alignment between the two shafts and to lock the one shaft in the changed axial alignment position.

For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawing, in which:- Figure 1 is a vertical section of a centrifugal pump located in a pipeline with a driven shaft thereof extending vertically upwards and connected by the coupling of this invention to a motor mounted above the 4 pump on a frame supported on the pump body with its driving shaft extending vertically downwards in line with the axis of the pump shaft, Figure 2 is an enlarged perspective view of the present coupling with portions being cut away to show the details of the connection between the coupling and the shafts, Figure 3 is a section taken on line 3-3 in Figure 2, and Figure 4 is a section taken on line 4-4 in Figure 2.

The pump 1 shown in the drawing is a centrifugal pump and is known in the industry as a vertical inline type of pump. The pump 1 includes a casing 6 having an inlet 7 and an outlet 8 adapted to be connected to the spaced ends of a pipeline (not shown) which usually supports the pump 1. The pump I is conventional and includes a centrifugal impeller 9 rotating in a pump chamber 10 connected to the inlet 7 and outlet 8. The pump impeller 9 is mounted on the lower end of a shaft 11 extending vertically upwards from the impeller 9 and is supported in a bushing 12 and a seal 13 mounted in the pump casing 6.

The pump 1 is driven by a driver such as an electric motor 15 mounted with its shaft 16 extending vertically downwards in line with the pump shaft 11. It should be recognised that the driving means could be another type of driver such as, for example, a steam turbine and that the invention is not limited to any particular type of driving means. The motor 15 includes an end plate 17 is surrounding the shaft 16 and mounted on a support frame 20 located between the pump 1 and the motor 15. The support frame 20 includes several vertical legs 21 extending between a top ring 22 and a bottom ring 2J. The bottom ring 23 of the support frame 20 sits on and is bolted to the easing 6 of pump 1 and the top ring 22 is bolted to the end plate 17 of the motor 15, resulting in the motor 15, support frame 20 and pump 1 being integrated into a single rigid unit which is intended to hold the two shafts 11 and 16 in axial alignment.

The two shafts 11 and 16 are interconnected by a coupling 25 which is an embodiment of this invention. The coupling 25 includes an elongate cylindrical body, also designated 25, having a bore 26 extending between its upper end 27 and lower end 28. The coupling 25 is split axially into a pair of semi-arcuate halves 29 and 30 which when installed are held together by bolts 31 located at both ends of the coupling and extending between the halves 29 and 30 as shown in Figure 2. The two halves 29 and 30 are clamped together around the ends of the pump and motor shafts 11 and 16 to interconnect. the shafts together for transmitting driving torque from the motor 15 to the pump 1.

Both the shafts 11 and 16 are keyed to the coupling 25 by keys 32 in a conventional manner. The motor shaft 16 includes an annular groove near its lower end which receives a pair of ring sections 33 that fit into a corresponding internal annular groove in the coupling 25 for locking the shaft 16 axially in the coupling 25. one of the ring sections 33 is locked in place in the 6 coupling 25 by a screw 34 extending through a bore in the coupling half 30 and threading into the corresponding ring section 33.

A shaft extension 36 is fixed to the upper end of the pump shaft 11 by means of a threaded portion 37 on the extension 36 received in a corresponding threaded hole in the end of the shaft 11. A washer 38 is located between the extension 36 and the shaft 11 with the threaded portion 37 of the extension 36 extending through the washer 38. The washer 38 is larger than the shaft 11 and is received in an internal groove formed in the coupling 25 to axially lock the pump shaft 11 in the coupling 25 in the same manner that the ring sections 33 lock the shaft 16 axially in the coupling 25. The upper or outer end of the shaft extension 36 is formed with wrench engaging flats 39 to enable the use of a wrench for threading the extension 36 in place on the end of shaft 11. The washer 38 is held in position by a screw 40 extending through a bore in the coupling half 30 and threading into the periphery of the washer 38.

The bore 26 of the coupling 25 is enlarged midway along its length to form the chamber 43 receiving the shaft extension 36. The majority of the shaft extension 36 is located in the chamber 43, where it is spaced from the walls of the chamber 43 so that it can be moved side-to-side.

The remainder of the shaft 11 and the extension 36 is held by the coupling 25 over a relatively small length of the coupling 25 so that the portion of the coupling 25 7 holding the shaft 11 and extension 36 serves as a fulcrum about which the shaft 11 and shaft extension 36 can pivot as the upper end of the shaft extension 36 is moved from side-to-side in the chamber 43. Moving the shaft extension 36 in the chamber 43 can serve to change the alignment of the shaft 11 in relation to the coupling 25.

Means is provided for moving the shaft extension 36 in the chamber 43 and locking the shaft extension 36 in place after the completion of the adjustment. As shown in Figure 4, four headless adjustment screws 44, similar to set screws, are threaded in the walls of the coupling 25 at ninety degrees relative to each other about the shaft extension 36. Each screw 44 is formed on its outer end for engagement by a turning tool such as, for example, an Allen wrench and includes a pad 45 on its inner end for engaging the side of the shaft extension 36. Each pad 45 is larger than the threaded portion of the screw 44 so that the screw 44 must be inserted into its threaded hole from the inside of the coupling 25 prior to being installed around the shafts 11 and 16.

Making the pads 45 larger than the threaded holes prevents the screws 44 from accidently backing out of their holes during use, in the event they become loose, which is not supposed to happen, but may occur under unusual and unexpected circumstances.

It should be seen now that the screws 44 can be used to adjust the relative position of the shaft extension 36, and its connected shaft 11, in the chamber 43 to adjust the alignment of the shaft 11 relative to the shaft 16 for aligning the shafts after the coupling 25 is mounted 8 on the shafts. In addition, the screws 44 serve to lock the shaft 11 in its relative position to the coupling 25 during the following operation of the pump 1 and motor 15.

The screw 34 is used to hold the coupling half 30 in place on the shaft 16 during assembly of the coupling and the screw 40 holds the coupling half 30 on the shaft 11 during assembly. The screws 34 and 40 remain in place during operation of the coupling although they only serve a function during assembly and disassembly of the coupling 25.

9

Claims

CLAIMS:

1. A coupling for interconnecting two axially aligned shafts together for transmitting torque from one shaft to - the other shaft, said coupling comprising an elongate cylindrical body having an axial bore therein extending over its length adapted to receive the adjacent ends of both shafts in substantial axial alignment, means for keying the ends of each shaft to the adjacent coupling body for transmitting torque between said shafts through said coupling body, fulcrum means on said coupling for firmly grasping one of said shafts at a point spaced from its end over a relatively short distance along the length of the coupling, the bore of said body being spaced from said fulcrum means and being substantially larger than the end of said one shaft whereby said one shaft can tilt along its length about the fulcrum means of said coupling allowing the axis of said one shaft to tilt to an inclined position relative to the axis of the coupling body and means in said coupling body for engaging the end of said one shaft and urging it to said inclined position relative to the axis of said coupling body for adjusting said one shaft relative to the coupling to change the relative axial alignment between the two shafts and to lock the one shaft in the changed axial alignment position.

2. A coupling according to claim 1, wherein said coupling body is split along its axis into a pair of semi-arcuate halves and fastener means is provided to clamp said halves together around the portions of axially aligned shafts.

3. A coupling according to claim 1 or 2, wherein the means for engaging and urging the end of said one shaft to an axially adjusted position includes several screws threaded into the coupling body at spaced locations around said one shaft and having means on their ends to engage said one shaft.

is

4. A coupling according to claim 3, wherein the means on the ends of said screws are larger thanthe threaded holes receiving said screws thereby preventing said screws from backing completely out of said threaded holes during operation of the coupling.

A coupling according to claim 3 or 4, wherein said one shaft includes a shaft extension removably attached to its end and extending into the enlarged portion of said bore and with the adjustment screws engaging said shaft extension.

6. A coupling for interconnecting two axially aligned shafts, substantially as hereinbefore described, with reference to the accompanying drawing.

7. A centrifugal pump incorporating according to any one of the preceding claims.

a coupling Published 1990 at The Patent Office, State House, 66 71 High Holborn. LondonWClR4TP. Further copies mkybe obtained from The Patent Office. Sales Branch. St Mary Cray. Orpington. Kent BR5 3RD. Printed by Multiplex techniques ltd. ST. Mary Cray. Kent. Con- 187 -1