Note: Descriptions are shown in the official language in which they were submitted.
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: TITLE: FLEXIBLE COUPLINGS
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: BACKGROUND OF THE INVENTION
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The invention set forth in this specification per-
tains to new and improved flexible couplings.
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Flexible couplings have probably been used since
shor~ly after the advent of the modern machine age for
the purpose of transmitting rotation from one shaft to
another. These couplings are normally used in order to
accommodate comparatively minor shaft alignment problems
such as are occasionally encountered because of manufac-
turing or assembly errors. Because of the fact that
these devices are widely used and have been known and
used for many years, it is not surprising that many
different types of flexible couplings have been pro~
posed, built and used.
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: Fortunatelyr an understanding of the present inven-
tion does not require a detailed consideration of all
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such prior couplings. It is considered that there is a
continuing need for new and improved flexible couplings
which are comparatively inexpensive, comparatively easy
to install and disassemble which are effective or their
intended purpose. The latter factor includes the abil-
ity to be used over a long period with no, or substan-
tially no, maintenance. It is considered that known/
prior couplings have not been as completely satisfactory
as desired in all the various ways indicated in the
preceding discussion.
The particular flexible couplings of the ~ype to
which this invention pertains have been manufactured in
the past so as to include two hubs or hub elements which
are adapted to be connected to the shafts joined by the
coupling. These hubs in these prior couplings are both
provided with extending lugs or teeth serving as holding
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means so as to be engaged by corresponding projections
on a band-like motion transmitting means in order to
cause the hubs to rotate in synchronism as one of the
shafts is rotated. The bands used in these prior coup-
lings have been flexible somewhat resilient bands cap-
', able of being wrapped around the hubs so that the pro-
jections on them engage to the holding means on the
hubs.
In these prior couplings non elastic retainers or
retainer bands have been u~ilized to secure the motion
transmitting means in place so as to prevent them from
disengaging the holding means on the hubs. In such
prior couplings the band has been secured in place by
what may be referred to as a peg or projection which i~
fitted within a correspondingly shaped cavity or slot in
the motion transmitting means.
; While flexible couplings of this latter category
unquestionably can be utilized very satisfactorily it is
considered that they are undesirable because of the
inclusion of the peg or projection and the slot or
cavity in the motion transmitting means. Obviously
there are costs involved in connection with the manufac-
ture of any such peg or projection or any such cavity or
slot~ Further, whenever an extending projection is used
there is at least a limited danger of the projecion
being damaged during handling of the parts of the coup-
ling as it is assembled or disassembled. Further the
use of a depression or slot in an elonga~ed flexible
band retaining member is considered to detrimentally
effect the strength characteristics of the band.
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. BRIEF SUMMARY OF THE INVENTION
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- As a consequence of these factors, it is considered
that there is a need for a new and improved flexible
couplings oE the type indicated in the preceding discus-
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'J, sion. More specifically it is considered that there is
a need for flexible couplings as subsequently indicated
1 because such couplings can be easily and conveniently
.. manufactured at comparatively low cost, may be easily
installed and used, because such couplings are very
j effective for their intended purpose and are capable of
being utilized with little or no maintenance for long
periods.
In accordance with this invention these various
objectives are achieved by providing a flexible coupling
for connecting two rotatable shafts, said coupling
including (1) two hubs, one of said hubs being capable
q of being connected to one of said shafts and the other
.~ 15 of said hubs being capable of being connected to the
other of said shafts, each of said hubs including
holding means accessible from the periphery thereof
! capable of being engaged so as to cause said hubs and
;~ said shafts to rotate in synchronism for use in
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transmitting rotation from one of said hubs to the other
of said hubs, (2) motion transmitting means extending
~ generally between said hubs and engaging said holding
: means on both of said hubs for use in cooperation with
said holding means in transmitting rotation from one of
said hubs to the other of said hubs and (3) retaining
. means positioned around said transmitting means for use
. in holding said motion transmitting means in contact
.~ with said holdin~ means during use of said coupling in
which the improvement comprises said motion transmitting
~ 30 means includes interior engagement means located in
:.: engagement with said holding means, said motion
.. ~. transmitting means having exterior engagement means
; capabl~ of being engaged by the interior of said
retainer means and being expanded outwardly in response
``. 35 to the centrifugal force, said motion transmitting means
is an elongated, flexible belt, said belt having an
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interior surface, an exterior surface, ends and sides,
j and wherein said interior engagement means are located
j on the interior of said belt, said exterior surface of
! said belt is convexly curved so that the medial portion
of said belt between said sides is of greater diameter
than said sides when said belt is positioned in said
coupling and serves as said exterior sngagement means,
and said retainer means is an endless band located
around said hubs and said motion transmitting means, the
interior configuration and dimensions of said band being
of a permanent concave configuration corresponding to
the exterior configuration of said belt such that said
band is capable of being slipped on or off of said
motion transmitting means when said motion transmitting
means are located so that said interior engagement means
are located closely to and in engagement with said
holding means and being of such dimensions so that
during rotation of said coupling said exterior
engagement means on said motion transmitting means will
be held by centrifugal force against the interior of
said band so as to prevent said band from being
~ disengaged from said motion transmitting means.
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BRIEF DESCRIPTION OF DRA~ING
Because of the nature of this invention it is best
;; more fully explained with reference to the accompanying
drawing in which:
Fig. 1 is a top plan view of a presently preferred
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embodiment of a flexible coupling in accordance with
this invention;
Fig. 2 is a cross-sectional view at an enlarged
scale taken at line 2-2 of Fig. 1;
Fig. 3 is a cross-sectional view taken at line 3-3
of Fig. 2;
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Fig. 4 is a partial cross-sectional view at an
enlarged scale taken at line 4-4 of Fig 3; and
Fig. 5 is a partial cross-sectional view
corresponding to Fig. 4 of a modified flexible coupling
in accordance with the invention.
The particular couplings illustrated in the
accompanying drawing are constructed so as to embody
the concepts and teachings of this invention summarized
and defined in the appended claims. Since these
~, concepts and features may be utilized in a variety
of somewhat differently appearing and differently
constructed flexible couplings through the use
of ordinary mechanical engineering skill on
the basis of the disclosure embodied in this
;'`.l specification and accompanying drawing
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the invention is not to be considered as being limited.
to the precise structures illustrated in the drawings
and described herein.
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DETAILED DESCRIPTION OF THE INVENTION
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In the drawing there is shown a flexible coupling
10 which is normally utilized to mechanically connect
two aligned or substantially aligned shafts 12. The--
coupling 10 includes two separate, identical cylindrical
hubs 14. These hubs 14 are provided with centrally
located shaft openings 16 which accommodate the shafts
12. These hubs 14 may be secured to the shafts 12
through the use of conventional set screws 18 on the
hubs 14 or in other conventional manners well known in
the fieldO Normally the precise methods of securing the
hubs 14 to the shafts 12 will be dependent upon the size
of the coupling 10 and the sizes o~ the shaft 12 with
which it is to be used. If desired the two openings 16
in the two hubs 14 may differ in dimension so as to
accommodate shafts 12 of different dimension.
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When these hubs 14 are mounted as shown they are
either in axial alignment or are nearly in axial
alignment and they are located on the shafts 12 so that
projecting teeth or lugs 20 (which, as subsequently
described serve as holding means) located on th~ir adja-
j cent ends 22 extend generally towards one another.
These teeth 20 will normally be spaced a short distance
from one another so as to avoid their periodically
i abutting against one another in the event the shafts 12
`) are not in precise alignment. During installation of
~' the coupling 10 the teeth 20 on the adjacent ends 22
will be brought into alignment with one another through
the rotation of one or the other of the shafts 12 as a
, belt 24 serving as a motion transmitting means is assem
;i bled on the hubs 14.
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This belt 24 is preferrably formed out of a some--
what flexible, somewhat resilient material capable of
transmitting a significant rotational force from one of
the hubs 14 to the other during the use of the coupling
10. Presently preferred results are achieved by forming
~' the belt 24 out of an appropriate polyurethane having
:,, the physical properties indicated. It has been found
,' that a urethane material is particularly desirable be-
~ cause it will give or flex sufficiently to accommodate
.,' minor misalignment of the shafts 12 without affecting
', its ability to be utilized over a long period.
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-',.,' As formed, this belt 24 has an exterior 26, an
,~. interior 28, sides or side edges 30 and ends 32. The
belt 24 will normally be just sufficiently long so that the
ends 32 will not quite meet when this belt 24 is located
~, around the teeth 20 as shown. When the belt 24 is in
-~ this position t~uncated wedge æhaped projections or cogs 34 on its
~. interior 28 extend between the teeth or axial ribs 20 on the hubs
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'~ 14 as shown so as to fit closely with respect to all of
-~ these teeth 20. These projections 34 can be ~onsidered
as interior engagement means on the belt ~4 which are
employed for the purpose of engaging the teeth 20 so as
? to transmit rotation from one of the hubs 14 to the
' other of the hubs 14.
The ex~erior 26 of the belt 24 is preferrably bowed
as shown,between the sides 30 so that the medial
... portion 36 of the belt 24 is of larger diameter when the
~, belt 24 is used in the coupling 10 than either of the
~ sides 30. It can be considered that the belt 24 has an
,:~ outwardly convex shape and that the exterior26 of it is
~, of uniform cross sectional configuration throughout the
`"7 length of this belt 24. The medial portion 36 of this
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,:i belt 24 may be considered as an exterior engagement
', means because the shape of this medial portion 36 is
:, important in connecton with a metal or other non-elastic
- retainer band or means 38 used with the coupling 10.
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The interior 40 of the band 38 is shaped and dimen-
sioned so that this band 3~ may be slid axially relative
to the hubs 14 during the assembly and disassembly of
the coupling 10 so that the band 38 fits over the belt
24 as shown when the coupling is assembled so as to
conform closely to the exterior 26 of the belt 24 when
this belt is installed. The interior 40 of ~he band 38
is also shaped and dimensioned so that when the coupling
10 is used centriugal force will expand the diameter of
the belt 24 to a limited or slight extent sufficient to
brin~ the medial portion 36 into contact with the in-
terior 40 of the band 38~
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The configuration of this interior portion is such
that it is complimentary to the exterior 26 of the belt
24. In effect this interior 40 may be referred to as
concave while the exterior 26 of the belt 24 may be
re~erred to as convex. In any event, because of these
complimentary configurations of the exterior 26 of the
belt 24 and the interior 40 of the band 38 during the
use of the coupling the band 38 will be engaged so that
it cannot slide off of the belt 24 while concurrently
the belt will be held so that it cannot disengage the
teeth from the hub 14.
When the coupling 10 is not being rotated it is
possible to remove the band3B by pushing or pounding on
it so as to tend to force the belt 24 closely into
engagement with the hubs 14 and the teeth 20 to a suffi-
cient extent to permit the band 38 to be slid axially
from the belt 24. At this point the belt 24 can be
peeled from the hubs 14 while disassembling the coup-
ling 10~ As a consequence of the manner in which the
band 38 fits with respect to the belt 24 ~here is no
necessity to worry about the precise alignment of a pin
or projection with a slot or cavity as the coupling 10
is assembled by a series of steps which will be obvious
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from the preceding discussion.
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If desired, the precise concave convex configura-
tion of the interior 40 of the band 38 and the exterior
26 o~ the belt 24 used in connection with the coupling
10 may be replaced with other substantially equivalent
or reasonably related structures. This is indicated in
Fig. 5 of the drawing where there is shown another
coupling 50 which is substantially identical to the
coupling 10. Since the coupling 50 is substantially
identical to the coupling 10 those parts of it which are
the same or substantially the same as those in the
coupling 10 are no~ separately described herein and are
designated in the drawing and when necessary for ex-
planatory purposes in the remainder of this specifica-
tion by the primes of the numerals previously used to
designate such parts.
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-~ In the coupling 50 the interior 40' of the band 38'
in cylindrical and is provided with very small terminal,
inwardly projecting flanges 52 of smaller diameter than
3, the remainder of the interior 40'. In the coupling 50
the sides 30' of the belt 24' are dimensioned so as to
~ ~it between these flanges 52 and the exterior 26' is
`~i flat prior to the use of the belt 24' and takes on a
1 cylindrical shape when the belt 24' is used. As a
-~ consequence of this structure when the coupling 50 is
employed the belt 24' will be held in place by being
expanded through centrifugal force into contact with ~he
interior 40' of the band 38' generally between the
` flanges 52. This coupling 50 may be assembled and
disassembled in substantially the manner indicated in
the preceding discussion. It will be recognized however
that a certain minimum difficulty will be encountered in
moving the band 38' relative to the belt 24'~
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