Note: Descriptions are shown in the official language in which they were submitted.
1~'7~()7~
IMPROVED FLEXIBI.E COUPLING
Background of the Invention
1. Fie]d of the Invention
This invention relates to flexible couplings and, more particularly, to
flexible couplings in which torque is transmitted between two shafts by means
of elastomeric elements in compression.
2. Description of the P_ior ~rt
Flexible couplings for transmitting torque between misaligned driving
and driven shafts by means of elastomeric elements in compression are old and
well known in the art, see IJ.S. Patent No. 2,~373,590. Such couplings have not
only demonstrated the ability to compensate for misalignment between the
driving and driven shaft but also to protect the driving and driven members
from shock loading and vibration. While over the years these couplings have
given good service in the field, assembly and disassembly is a difficult
problem because the elastomeric elements must be inserted in the cavity formed
by the sleeve and hub axially and be precompressed during the process of
insertion. This problem of precompression during insertion becomes
increasingly severe as the size of the coupling increases. Also, if the
coupling must be disassembled, as in the case when the coupled machinery must
be replaced, all the elastomeric elements are normally damaged in the process
and must be replaced, thereby increasing the cost of maintenance. Further, the
cost of these types of couplings has always been relatively high. For the
foregoing reasons these type flexible couplings have not achieved the degree of
acceptance in industry that the performance and reliability they provide would
ordinarily have achieved.
Summary of the Invention
The present invention overcomes the foregoing problems of the prior art
by providing a flexible coupling in which the elastomeric elements can be
~,
assembled into the coupling or removed therefrom radially. The elastomeric
elements are inserted into the sleeve segments and assembled radially over a
hub blade without the need of the degree of precompression required by the
prior art. The present invention minimizes the problem of assembly and
disassembly. Also, the cost of the coupling has been significantly reduced.
The sleeve element of the coupling is comprised of a plurality of
segments adapted to retain the elastomeric elements in operable contact
with the coupling hub which is mounted on a driving or driven shaft. The
individual elements of the sleeve are mated to the rigid hub which is
10mounted on a driving or driven shaft by means of a retainer means. The
retainer means is fixed to the rigid hub by means of fasteners.
Brief Description of the Drawings
Figure 1 is an isometric view of the coupling of the present invention
in the process of being assembled;
Figure 2 is a fragmentary end view, in section of the coupling of the
present invention;
Figure 3 is a fragmentary side view, in section of the coupling of
Figure l;
Figure 4 is a fragmentary side view, in section, of two couplings of the
20present invention in a back-to-back arrangement;
Figure 5 is a fragmentary side view, in section, of a flywheel mounted
coupling of the present invention; and
Figure 6 is a fragmentary end view, in section, of an alternate
embodiment of the coupling of the present invention.
Description of the Preferred Embodiment
-
Referring to Figure 2, the coupling of the present invention generally
designated 10 is comprised of a hub 12 which is made of steel and is adapted to
he keyed to .1 shaft, 14 by means of key 16. Fixed to hub 12 by a weld 18 are a
l~t7~074
plurality of blades 20. It will be understood that a conventional cast hub can
be used in place of this fabricated hub. In the preferred embodiment, hub 12
has five blades. As will be described below, the hub may have less or more
blades than the preferred embodiment. As shown in Figure l, each blade 20 is
adapted to abut the adjoining blade at interface 22. Each blade is of like
length and width.
The sleeve element of the coupling is comprised of a plurality
of part cylindrical or C-shaped segments 28. Segments 28 are determined
by displacing a straight line parallel to itself while being perpendicular
to and constantly intersecting a planar curve defined by three arcs and
two lines. In the preferred embodiment, since the hub 12 has five blades
20, the sleeve is comprised of five part cylindrical metallic segments.
Each segment must be of identical axial length and at least as long as
blades 20. The faces 33 and 34 thereof must be parallel to each other
and perpendicular to the outer periphery 35. Each of the segments 28
are placed around the blades of hub 12 as shown in Figure 1. The segments
28 are constructed so that the angle between the straight portions 29 is
slightly less than 360 divided by 5, it being understood that if more or
less than 5 segments are used then the angle between the straight portions
will be less than 360 divided by the number of elements. This will
insure that when the segments 28 and blades 24 are assembled around hub 12
as described below, the segments 28 will contact in the area of tips 31,
but when the coupling is finally assembled the straight portions 29 will
mate and form interface 30 of significant area. Elastomeric elements 24
of this preferred embodiment are solid cylinders of an elastomeric material
such as rubber.
-- 3 --
0~7~
As shown in Figure 1 when a pair of elastomeric elemen~s 24
are inserted in segments 28 and segments 28 of the sleeYe are placed around
the blades 20 of hub 12 a small amount of precompression is created in
7~
each element 24. The assembled hub and sleeve is now placed between retainer
ring 26 and rigid hub 36, Figures 1 and 3. However, retainer ring 26 is
independent of hub 12 and shaft 14. Rigid hub 36 is mounted on driven shaft
46. The assembled hub and sleeve are now fixed between the retainer ring 26
and the rigid hub 36 by means of bolts 40 which extend through openings 42 in
rigid hub 36 and 44 in retainer ring 26. In the preferred embodiment five
bolts are used for symmetry with the blades of the hub 12 and
segments 28.
6RS
~ Retainer ring 26 and rigid hub 36 have mirror image ~ffl~crs 32 and 38.
Because of chamfers 32 and 38 and the clamping effect caused by bolts 40, the
segments 28 move radially toward the axis of the coupling compressing
the elastomeric elements 24 in the process of clamping. Whereas the
segments 28 of the sleeve are solidly clamped between retainer ring
26 and rigid hub 36 by reason of the contact with faces 33 and 34, the hub 12
is free to move, within limits, in the axial, radial and angular directions so
that the coupling can accommodate misalignment be~ween the driving and driven
shafts.
It is clear from the foregoing that rotation of shaft 14 will cause
rotation of hub 12 and blades 20. Torque will be transmitted from blades 20 to
elastomeric elements 24 to sleeve segments 28 which are fixed to rigid hub 36.
The torque will cause rotation of hub 36 and shaft 46.
An alternative embodiment of the coupling is shown in Figure 4 when two
such couplings are used to correct relatively large misalignments. This
arrangement is known in the art as "full flex". In this embodiment driving hub
12 transmits the torque to a driven hub 48 through two couplings as described
in the preferred embodiment minus the rigid hubs but interconnected by a common
plate 50. In this embodiment the bolts 40 of each coupling are threaded in
staggered and tapped holes 52 of said plate 50. Plate 50 has chamfered guides
07'~
54 and 56 on both sides to accommodate the cylindrical segments 28 of the
sleeves as previously described. In order to maintain a reasonable dynamic
balance guide bushings 56 may be used bstween retainer rings 26 and hubs 12 and
48.
Another embodiment of the coupling of the present invention is used in
connection with internal combustion engines. The coupling is mounted on the
engine's flywheel 58, as illustrated in Figure 5. An adapter 60 is bolted to
the flywheel 58 in a conventional manner. The adaptor, which acts as a rigid
hub, is provided with chamfered guides 62 and tapped holes 64. Cylindrical
segments 28 are fitted in the same manner as previously described, using
retainer ring 26 and bolts 40. The torque from the flywheel is thus trans-
mitted to the shaft 14 through the hub 12.
It is known that the present invention could be embodied in a configura-
tion other than a circular one. One such configuration is illustrated in
Figure 6.
If desired in any embo~iment of the present invsntion, a continuous cir-
cumferential band 66 can be welded to the outside circumference of the
elements 28, as shown typically in Figure 3. It will be understood,
however, that use of band 66 eliminates the advantage of radial assembly of the
elastomeric elements but the cost benefit of the invention is retained.
While I have described certain preferred embodiments of my invention, it
will be understood that it may otherwise bs embodied within the scope of the
following claims.
-- 5 --
