Shaft coupling with alignment adjustment device

A centrifugal pump mounted in a pipeline with its driven shaft extending vertically and a driving motor spaced above the pump on a support frame attached to the pump body and supporting the motor. The shafts of the motor and pump are vertically aligned and interconnected by a coupling that enables the end portion of one shaft to be swiveled in the coupling to adjust the alignment of the shaft axis with the axis of the other shaft and threaded screws for forcing the shaft end to an adjusted position and locking it in the adjusted position during use of the pump.

BACKGROUND OF THE INVENTION 
This invention relates to a coupling for rigidly interconnecting the shafts 
of rotating machinery in axial alignment and more particularly to a 
coupling containing 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 fully and 
independently support 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 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 interconnected 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 insure that 
the shafts are in axial alignment and remain in such alignment during use 
of the machinery. 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. 
SUMMARY OF THE INVENTION 
An object of this invention is to provide a rigid coupling 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 swiveled position 
relative to the coupling and to the axis of the other shaft engaged in the 
coupling.

DESCRIPTION OF PREFERRED EMBODIMENT 
The pump 1 shown in the drawings 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 
1 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 upward 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 the electric motor 15 mounted with 
its shaft 16 extending vertically downward in line with the pump shaft 11. 
It should be recognized 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 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 
23. The bottom ring 23 of the support frame 20 sits on and is bolted to 
the casing 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 FIG. 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 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 of 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 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 FIG. 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 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. 
While only one embodiment of this invention is shown and described in 
detail, this invention is not limited merely to the specifically described 
embodiment, but contemplates other embodiments and variations utilizing 
the concepts and teachings of this invention.