Note: Descriptions are shown in the official language in which they were submitted.
CA 02206923 1997-06-04
IMPROVED BALANCING ARRANGEMENT FOR HOLLOW DRIVE SHAFTS
FIELD OF THE INVENTION
The invention relates to a balancing arrangement, and more
particularly to an improved balancing arrangement for hollow drive
shafts which allows for the compensation of greater imbalances.
BACRGROUND OF THE INVENTION
Balancing arrangements of various types are known in the prior
art. For example, U.B. Patent 3,901,046 to Hofmann discloses a
balancing arrangement utilizing a clip to be tightened on the
rotating member whereby counterweights are affixed to the clip
within an area substantially opposite the connection of the free
ends of the clip by means of a screw-type (worm-drive) connection.
This type of arrangement is relatively complicated in installation
because of the time-consuming determination of the imbalance and is
also relatively inefficient because the counterweight must always
offset also the screw-type connection of the open ends of the
clip.
My prior British Patent 2,238,846 avoids the shortcomings and
drawbacks of Hofmann by placing the counterweight within the area
of the mechanical connection of the open clamping band. With the
earless construction as disclosed in Figures 1-5 of this patent,
sections having concavely shaped lateral band portions with an
hourglass-like window defined therebetween are used to impart
elastic stretchability in the longitudinal direction to the
clamping band to compensate for thermal fluctuations of the drive
shaft. The counterweight is thereby affixed to the clamping band
by hook-like projections. In the embodiment of Figures 6-12 of
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CA 02206923 1997-06-04
. this patent, the tightening member is constituted by a plastically
deformable ear whereby in Figures 10-12 the ear is made in one
piece with the counterweight.
My U.B. Patent 5,230,246 differs from the aforementioned
British patent by a special construction of the plastically
deformable ear which is provided with tab-like members intended to
perform the dual function of avoiding problems in case of
positional changes of the balancing arrangement and of increasing
the strength of the ear-like member.
Hollow drive shafts are made to specified dimensions with a
given accuracy. However, the greater the permissive tolerance in
the external dimensions of the shaft, i.e., the greater the
possible imbalance in the drive shafts, the greater must be the
weight range of the counterweights to compensate for the imbalance.
In other words, if drive shafts can be manufactured with lesser
accuracy in the external dimensions which is desirable from a
manufacturing cost point of view, then it becomes important to
provide a balancing arrangement which is capable of securely
handling counterweights of greater weight.
Recent developments have indicated a need to double the size
of the maximum weight of the counterweight to be usable in the
balancing arrangement. However, this goal has appeared
unattainable with balancing arrangements as disclosed in the
aforementioned British and U.S. Patents.
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CA 02206923 1997-06-04
SUMMARY OF THE INVENTION
It is therefore a principal obj ect of the present invention to
provide a balancing arrangement and a preassembled clamp structure
with an integral balancing counterweight which efficiently obviates
the shortcomings and drawbacks encountered with the prior art
constructions and assures reliable secure holding of counterweights
with double the weight contemplated heretofore.
The underlying problems are solved according to this invention
by a specific arrangement of the combination of clamp structure and
counterweight. More specifically, the mechanical connection of the
clamp structure must be able to withstand greater tightening forces
for the increased weight of the necessary maximum counterweights
and, with the use of a so-called "Oetiker" ear, the holding ability
of the ear must also be substantially increased.
It has also been discovered that for most purposes, so-called
"Oetiker" ears are able to provide sufficient compensation for
thermal temperature changes of the drive shaft so that it is
sufficient to provide elasticity on the part of the clamping band
by the use of a clamping band of generally concave shape in
transverse cross section. Elasticity may also be imparted to the
counterweight by the use of a radius of curvature of its internal
surface slightly smaller than the radius of curvature of the drive
shaft.
A surprisingly greater holding ability of a clamp with a so-
called "Oetiker" ear is attained by utilizing two side-by-side
longitudinally extending reinforcing grooves having each a
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CA 02206923 1997-06-04
rounded-off bottom and delimited by substantially parallel side
surfaces interconnected by semi-circular end surfaces, especially
also with the use of a wider clamping band than normally used
heretofore. A satisfactory holding ability could be attained with
these modifications.
In case of the use of a so-called earless clamp in such a
balancing arrangement, a strong mechanical connection of the clamp
can be achieved with the use of a new support hook engaging from
below into a tunnel-shaped aperture to securely hold the earless
clamp structure in its installed and fully tightened position. The
improved support hook offers greater resistance against buckling or
collapse of the hook under the load of the outer clamping band
portion during tightening and at the same time facilitate the
sliding movement of the outer clamping band portion over a flat top
portion in the novel support hook during tightening.
Additionally, it has also proven advantageous to connect the
counterweight permanently to the clamping band by spot welding
within the area of the inner band end portion between the
mechanical connection and the free end in the inner band portion
which permits an inexpensive and efficient preassembly of
counterweight and clamp structure. In the alternative, a simple
mechanical connection within the same area with a centering
arrangement of the counterweight may be used in a modified
embodiment of this invention.
In the case of a so-called earless clamp structure, a
pressed-out reinforcement in the area of the free end of the outer
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CA 02206923 1997-06-04
_ band portion has also proved highly successful to avoid lifting up
of the band during tightening of the clamp structure and to improve
the stability of the tunnel-shaped member located near the free end
of the outer band portion and involved in the tightening of the
clamp structure.
In order to improve the effectiveness of the counterweight,
the area of the clamping band opposite the mechanical connection
and of the counterweight may be subjected to a weight reduction by
the removal of clamping band material with the use of openings of
various sizes, shapes and dimensions as well as of a varying number
of such openings, as will be described more fully hereinafter.
BRIEF DESCRIPTION OF THE DRAWING
These and other objects, features and advantages of the
present invention will become more apparent from the following
description when taken in connection with the accompanying drawing
which shows, for purposes of illustration only, several embodiments
in accordance with the present invention, and wherein:
Figure 1 is a plan view on a clamp structure of one embodiment
for use in the balancing arrangement of the invention;
Figure 2 is a side elevational view of the clamp structure of
Figure 1;
Figure 3 is a cross-sectional view, taken along line A-A of
Figure 1;
Figure 4 is a cross-sectional view, taken along line B-B of
Figure 1;
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CA 02206923 1997-06-04
_ Figure 5 is an end elevational view, taken in the direction of
arrow C of Figure 2;
Figure 6 is a somewhat schematic partial plan view on an
enlarged scale of certain details of the guide-and-support hook and
of the support hook in the clamp structure of Figures 1 and 2;
Figure 7 is an axial elevational view of the clamp structure
in the non-tightened condition;
Figure 8 is a side elevational view of Figure 7:
Figure 9 is a schematic plan view of a modified embodiment of
the combination of clamp structure and counterweight for use in a
balancing arrangement of this invention;
Figures 10A, 1oB and lOC are graphs representing the test data
obtained with a clamp structure having a reinforced ear structure
as disclosed in U.S. Patent 5,230,246;
Figures 11A, 11B and 11C are graphs representing the test data
obtained with a clamp structure equipped with a reinforced
plastically deformable ear of this invention;
Figure 12 is a somewhat schematic partial plan view on a
modified embodiment of a so-called earless clamp structure for use
in a balancing arrangement of this invention;
Figure 13 is a side elevational view on an enlarged scale of
a new improved support hook forming part of the mechanical
connection of an earless clamp structure;
Figure 14 is an end elevational view of the support hook of
Figure 13;
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CA 02206923 2000-07-28
Figure 15 is a partial plan view on the support hook of
Figure 13;
Figure 16 is a partial plan view on an enlarged scale,
showing a preferred embodiment of the novel reinforcement used
in the end area of the outer band portion of the earless clamp
structure of Figure 12;
Figure 17 is a cross-sectional view, taken along line D-D
of Figure 16;
Figure 18 is a cross-sectional view, taken along line E-E
of Figure 16;
Figure 19 is a partial plan view on the clamping band of
a clamp structure with a modified construction of a weight-
reducing opening;
Figure 20 is a somewhat schematic slightly perspective
view of a plate-like counterweight member for use in this
invention; and
Figure 21 is a cross-sectional view taken along line 21-
21 of Figure 20.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring now to the drawing wherein like reference
numerals are used throughout the various views to designate
like parts. The present invention is related to British
Patent 2,238,846 as well as U.S. Patent 5,230,246.
Referring first to Figures 1-8, reference numeral 10
generally designates a clamp structure which is provided with
a so-called
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CA 02206923 1997-06-04
"Oetiker" ear generally designated by reference numeral 3o and a
mechanical connection generally designated by reference numeral 40
(Figure 7). The clamping band 10 includes an inner band portion
10a and an outer band portion i0b which, in the installed condition
mutually overlap, at least in part. The lateral band portions 10~
and 10~~ are bent down (Figure 5) to impart elasticity to the
clamping band by a more or less convex shape which seeks to flatten
out as the clamp structure is tightened about the counterweight and
rotating shaft. The lateral edges of the bent-down portions 10~
and 1o~~ will seek to dig into the external surfaces of the
rotating member (not shown) and of the counterweight. To enhance
the anchoring, these edges may also be non-smooth as realized by
any means described in my aforementioned British and U.S. Patents.
The modified, plastically deformable ear generally designated
by reference numeral 30 which serves as tightening means includes
two generally outwardly extending leg portions 31 and 32
interconnected by a bridging portion 33 which is provided with a
novel reinforcement arrangement (Figures 2 and 3). In the
illustrated embodiment, the ear reinforcement arrangement is
constituted by two groove-like reinforcing indentations 34, each
having a rounded-off bottom 35, whereby each reinforcing groove is
formed by substantially parallel, longitudinal side surfaces
interconnected at each end by substantially semi-circularly shaped
end portions as shown in Figures 1 and 3. The side surfaces as
well as the end surfaces of a respective groove-like indentation 34
thereby slope down toward one another at an angle oC with respect
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CA 02206923 1997-06-04
to the vertical, for example, at an angle of about. l5° to merge
into the rounded-off bottom.
The mechanical connection generally designated by reference
numeral 40 includes two cold-deformed, deep-drawn support hooks 41
which may be constructed as disclosed in my prior U.S. Patent
4,299,012 or as shown more particularly in Figures 1, 2 and 6 of
this application. Following the two support hooks 41 in a
direction away from the free end of the inner band portion loa is
a novel guide and support hook 43 bent out of the clamping band
about an axis extending generally in the longitudinal direction
after two cuts as shown in greater detail in Figure 6. The
combined guide and support hook 43 includes, in addition to the
usual upwardly extending oblique guide surface 43~ (Figure 2) a
forwardly extending tip with a slightly downwardly extending tip
end portion 43~~ to reliably prevent disengagement of the outer
band portion 10b from the combined guide and support hook once the
clamp structure is preassembled before tightening by engagement of
the combined guide and support hook 43 in the slot-like aperture 44
in the outer band portion lOb. This particular configuration of
the combined guide and support hook 43 is achieved by a first cut
43a and a subsequent part-circular second cut 43b which are made
before the guide hook is bent out of the clamping band plane into
its substantially vertical position. Rectangular, preferably
square apertures 42 are provided in the outer band end portion lOb
to receive the support hooks 41 as the two band end portions 10a
and lOb are drawn toward one another by the surface 43~ as the
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CA 02206923 1997-06-04
clamp is tightened by plastic deformation of the ear 30. The
counterweight, generally designated by reference numeral 60 and
shown in Figure 1 in dash-and-dotted lines, which may be of any
suitable size and/or thickness, is secured to the inner clamping
band portion l0a intermediate its free end and the first support
hook 41, for example, by welding schematically indicated at 70. To
improve the anchoring of the counterweight, its corners 61 are bent
down (not shown) so as to dig into the outer surface of the
rotating member as the clamp structure is tightened. However, in
addition to the anchoring achieved by the bent-down corners 61 or
in lieu thereof, any of the anchoring arrangements disclosed in my
aforementioned British and U.S. Patents may also be used. The
counterweight of predetermined weight and size may be made of any
known material suitable therefor, such as of lead and alloys
thereof, powdered metals or even of a commercially available lead
tape provided with an adhesive surface which would also enhance
anchoring.
To further the effectiveness of the counterweight as regards
its effective weight, it is desirable to remove mass from the area
of the clamp structure opposite to the counterweight. In the
embodiment of Figure 1, a number of rectangular apertures 20a, 20b,
20a, 2od and 20e are provided, which are located in the area of the
clamp structure at least approximately opposite the area of the
mechanical connection and the counterweight. The size and number
as well as the configurations of the apertures may be selected as
desired for a particular application, depending also on the
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CA 02206923 1997-06-04
- strength of the material for the clamp structure. In the
embodiment of Figure 1, a relatively longer aperture 2oc is
followed on each side by two or more smaller apertures 20a, 20b and
20d, toe with each aperture of substantially rectangular
configuration having rounded-off corners. The width dimension of
the web portions 21 between adjacent apertures, i.e., the dimension
of these web portions 21 in the clamping band longitudinal
direction, may again be chosen depending on the type of material
used, for example, galvanized steel or stainless steel which have
different strength properties. As a rule of thumb, the width of
these web portions 21 should be at least about 20% to about 25% of
the width of the clamping band. The circumferential area of the
clamp structure covered by such apertures again depends on the
strength of the material and can be empirically determined readily
to optimize a given design. However, it follows that the greater
this circumferential area, the greater will be the effect of the
counterweight.
Figure 9 illustrates a modified embodiment of a clamp
structure for use in the balancing arrangement of this invention in
which the rectangular apertures 20a, 20b, 20c, 20d and 20e of
Figure 1 are replaced by circular apertures 120 which may extend
over substantially the entire clamping band portion intermediate
the inner and outer band end portions 10a and lOb because of
greater strength of this arrangement. Of course, it is also
possible to use oval apertures and/or a combination of regularly or
non-regularly following oval and circular apertures. As to the
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CA 02206923 1997-06-04
rest, the embodiment of Figure 9 is similar to that of Figures 1
through 8.
Of course, in lieu of rectangular, circular or oval apertures
or any mixture thereof, the clamping band used in the various
embodiments of this invention may also be provided with elasticity-
enhancing sections having concavely shaped lateral band portions
defining therebetween an approximately hourglass-shaped window, as
disclosed in the aforementioned British patent or in 0.8. Patent
5,230,246. However, as such elasticity-enhancing sections entail
certain difficulties in their manufacture by stamping out the
concavely shaped outer edges of the lateral band portions,
according to a modified embodiment illustrated in Figure 19, the
clamping band 10 may be provided with one or preferably several
sections 220, each provided with a window 221 resembling the shape
of an hourglass but retaining the substantially rectilinear outer
edges 222a and 222b. The size, i.e., length and width as well as
the curvature 223 of each section 220 and the width of the web
portions 224 may be readily determined empirically to optimize the
desired results in a given application, whereby the curvatures 223
are preferably part of a circular arc with a radius of curvature
greater than one half, preferably two-thirds of the width of the
clamping band. The window 221 also preferably has rounded-off
corners 225 with a radius of curvature substantially smaller than
the radius of curvature 223.
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CA 02206923 1997-06-04
The following tests demonstrate the surprising greater holding
ability of the ear structure of this invention compared to that of
the reinforced ear structure of U.S. Patent 5,326,325.
Table I sets forth the test data obtained with three clamp
samples having the reinforced ear structure according to my
aforementioned U.S. Patent 5,326,325, while Figures 10A, lOB and
lOC are graphs representing the test data obtained with the ear of
the aforementioned patent.
Table II shows the test data obtained with three clamp samples
having an ear construction according to the embodiment of Figures
1 through 5, while Figures 11A, 11B and 11C again show graphically
these test results.
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CA 02206923 1997-06-04
C
m G~m
> 1: C?00 2. C)C?C)S. C?00 ~. C?00 <h;.'. tmrr~)
<
mm
Extension
5 E88.5 718.7 E52.U 72~.~ ~.ES1
518
Load 1 CN7. . SSS. EO~. JOL.. E4S.:. 8. C?52
8 E L S
588
Load 2 (N) . 558 5 581.4 ES ~ ~_~7S
~ 8 . ?~.~
371 C)
_-, <NJ . - _ __ __ __
Load . ~ ~ _
~ _
-
___________ __-4'E_ _-~IU.4 E34.8 Eli.S E'~'~_E E.47E
J ~
mean 5 i 7~. E . . E5. ~5. 1 . S.
8U E5 ~ E S:!
standard . .
deviation
TABLE I
=m ~-'-
m
~x tan=.i:-~n 1 . C)C)i~_. c_~c-')S. c_ 4. C?C) CN ~ Cmm)
Crm.'. _) ~ '?C)
'Cad _ ,.NO ~4i).~- 75~:.~ 8WQ.V V'J'..~.w.i:~C)~) '~.;~04
vC~V ~ L~.? '' W). V~)i. 7CC. VJ'.. 1I-~~ J.C?.'w~'
vl G .J ~ I)
_ _,-/ .--~ ) c _. ~ c s . G r, r..-,, , c ~ 1 C)
~C~~ V CNJ .. 7vJt. r, , . _) C) . JLv
w .v 1 JL.V. 7 1 :
E 'JL1
mean S8. U ~G55. 8I~+. S~1 . 1C?C)C? 5: 5~~
C) i ~i
s tandard 177. S cc l ~~'. 4'~. C?. G C ).
. ~ ci ~~ 45S
deviati~_n . _
TABLE II
-13a-
CA 02206923 1997-06-04
A comparison of these tests reveals that the holding ability
of the ear of the embodiment of Figures 1 through 5 is greatly
improved over that in my 0.8. Patent 5,230,246.
As the tightening device in the form of a so-called "Oetiker"
ear may not be desirable in some applications, it may become
preferable to use a clamp structure in the balancing arrangement
which obviates the "Oetiker" ear. Low-profile, also so-called
earless clamp structures are known, for example, from my prior U.s.
Patent 4,492,004 in which the hooks in the inner band portion and
their apertures in the outer band portion must be so located that
the hooks can engage in these apertures only when the clamp has
been tightened to the extent necessary to provide the predetermined
clamping force, their location being thus also a function of the
clamp size. Figure 12 illustrates an improved low-profile, earless
clamp structure for use in a balancing arrangement of this
invention which has an improved mechanical connection, increases
reliability in effecting the mechanical connection and is designed
for easy and secure fastening of a counterweight. The clamping
band generally designated by reference numeral 210 which is
preferably made also of greater width like clamping band 10, is
again provided with lateral bent-down portions 210 and 210~ and
includes an inner band end portion 210a and an outer band end
portion 210b. Starting from the free end of the inner band end
portion 210a, an elongated aperture 221 is provided with rounded-
off end portions to receive a corresponding knub-like pressed-out
part in the counterweight (not shown) which fits into aperture 221
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CA 02206923 1997-06-04
for centering purposes. The counterweight may be of any known
construction as disclosed in connection with counterweight 60 of
Figure 1. Next follows a tunnel-shaped member 231 pressed out by
deep-drawing after two transverse cuts which forms part of the
disconnecting means and is followed by a novel support hook 232
forming part of the mechanical connection and capable of absorbing
higher circumferentially directed tightening forces in the
completely tightened and installed condition of the clamp
structure. The support hook 232 is again followed by a tunnel-
shaped member 233 which forms part of the connecting means for
tightening the reusable clamp structure. Next may follow a number
of apertures, for example, circular apertures 220 alternating with
oval apertures 220, the number and arrangement of which may be
varied as known to those skilled in the art. Of course, also
apertures as shown in Figure 1 or apertures as shown in Figure 19
may be used. In the alternative and/or in addition thereto also
elasticity-imparting sections as disclosed in my British patent or
in my U.S. Patent 5,230,246 may be used, the location of such
apertures and/or sections being preferably again at least within an
area of the clamping band approximately opposite to the
counterweight and/or mechanical connection and extending over a
circumferential part of the clamping band which may include all but
the clamping band end portions 210a and 210b. Another tunnel-
shaped member 234 which serves as part of the disconnecting means
is adjoined directly by a substantially rectangular opening 222
provided with a tongue-like preassembly projection 223 in the
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CA 02206923 1997-06-04
transverse surface nearer the free end of the outer band portion
210b which is adapted to engage with tunnel-shaped member 231 to
provide a preassembly. The opening 222, which is of such width
that the tunnel-shaped member 231 can extend into the same, is
followed by a tunnel-shaped member 235 forming part of the
tightening means for tightening the reusable clamp. A pressed-out
reinforcement 250 surrounds at least partially the tunnel-shaped
member 235 in the free end area of the outer clamping band end
portion 210b which surprisingly prevents a lifting-up of the free
end of the outer band end portion when tightening the clamp and
also imparts greater stability to the tunnel-shaped member 235.
The tunnel-shaped member 231 is thereby of smaller configuration
than tunnel-shaped member 234 so that it can slide under the
latter, if necessary.
A preferred embodiment of the front end reinforcement 250 is
shown in Figures 16, 17 and 18 in which the reinforcement 250
extends not only transversely in front of tunnel-shaped member 235
with its transversely extending part 252 but also extends laterally
of this tunnel-shaped member 235 in the longitudinal direction with
its lateral parts 251 to thereby surround the tunnel-shaped member
235 in front thereof and along the sides thereof over at least
nearly half the length. This reinforcement 250 effectively
prevents the free end of the outer band end portion 210b from
lifting up when the clamp is tightened by engagement of a pincer-
like tool at tool-engaging surfaces 235~ and 233~.
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CA 02206923 1997-06-04
Figures 13, 14 and 15 illustrate the details of the novel
support hook 232 of this invention which forms part of the
mechanical connection and which is pressed out by deep-drawing
after a cut limited substantially to the circular portion 232b~~
(Figure 15) to assume the configuration as illustrated in Figure 13
in which the substantially rectilinear ramp-like surface 232a
slanting obliquely upwardly away from the free end of the inner
band portion terminates in a substantially flat portion 232b
forming a nose-like part 232c, by means of which, in the connected
position, it engages from underneath in the opening of the tunnel-
shaped member 235 in such a manner that the nose-like part 232c
extends over and engages with the slanting guide surface 232d at
the edge in the band end portion i0b formed by the transverse cut
of the tunnel-shaped member 235 nearer the reinforcement 250.
Engagement of the nose-like projection 223 in tunnel-shaped member
231 provides a preassembled condition. The substantially
rectilinear slanting surface 232a and its flat portion 232b thereby
facilitate tightening of the clamp structure as the outer band end
portion 2lob reinforced by reinforcement 250 slidingly rides up
this ramp-like surface 232a and passes over the flat portion 232b
during tightening of the clamp structure until the nose-like part
232c is able to snap into the opening underneath the tunnel-shaped
member 235 so that the surface 232d can now engage with the
transverse edge of the clamping band caused by the transverse cut
for the tunnel-shaped member nearer the reinforcement 250. The
flat portion 232b thereby improves the support hook 232 in several
respects. The flat portion 232b greatly strengthens the hook 232
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CA 02206923 1997-06-04
against buckling or collapsing as the outer band portion 2lob
slides up over the ramp-like surface 232a during tightening of the
clamp, particularly as it reaches the upper end of this ramp-like
surface. The flat portion 232b also facilitates the sliding
movement of the outer band portions 210b during tightening of the
clamp as it not only shortens the ramp-like surface 232a but
facilitates this sliding movement by eliminating the inclined top
portion of the ramp-like surface of prior support hooks and instead
provides a flat surface which has a substantially constant radial
distance in the installed clamp.
The earless clamp structure of Figures 12 through 18 is
thereby installed and disassembled in a conventional manner as
known to those skilled in the art by utilizing a tool seeking to
draw together from the preassembled condition the tunnel-shaped
members 233 and 235 and by utilizing a tool seeking to draw
together the members 231 and 234 for reopening the clamp structure.
In lieu of a welded connection of the counterweight to the
clamping band, the embodiment of Figure 12 also illustrates
cutouts 271 ~ and 271 ~ ~ in the inner band end portion for fastening
the counterweight which may be provided with corresponding hook-
like members cut out from the counterweight by substantially
parallel cuts and bent-up so that they can extend through these
cutouts 271 and 271~ ~ and then be bent over to securely fasten the
counterweight in the preassembled condition, whereby the knub-like
projection engages in aperture 231 to hold the counterweight
centered.
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CA 02206923 1997-06-04
Typical values for the various embodiments are as follows, it
being understood that these values are typical merely for one given
embodiment of the invention and are not to be construed as
limitative in any way of possible embodiments of this invention
which may be varied as known to those skilled in the art. All
dimensions indicated hereinafter are in millimeters and are taken
from the drawings attached to the provisional application. The
length dimension a depends on the diametric dimension of the clamp
and in this particular embodiment is about 334 mm. and represents
the length of the clamp from the free end of the inner band portion
10a to the edge nearer the free end of the outer band portion of
the second aperture 42. The dimension b from this same edge of the
second aperture 42 to the free end of the outer band portion 10b is
about 21 mm. so that the overall length of the entire clamp is
about 355 mm. The width c of the clamping band is 14 mm. and the
dimension d from the free end of the outer band portion lOb to the
outwardly extending leg 31 of the plastically deformable ear 30 is
about 34 mm. The apertures 42 are each about 5.5 mm. in the
clamping band transverse direction and about 5 mm. in the
longitudinal direction of the clamping band. The width of the
slot-like aperture 44 in the transverse direction is about 2 mm.,
and its length in the longitudinal direction is about 6 mm. The
spacing between mutually facing edges of the apertures 42 is about
3 mm. which is also the spacing between adjacent edges of the slot-
like aperture 44 and the first, i.e., next-adjoining aperture 42.
The length a of the ear 30 in the longitudinal direction of the
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CA 02206923 1997-06-04
clamp is about 10 mm., and the height f is about 3.5 mm. The
length g of each groove-like indentation 34 is about 6 mm., the
radius of curvature of the rounded-off bottom 35 of each groove-
like indentation is about 1 mm, and the spacing h between the
centers of the bottoms of the groove-like indentation in the
clamping band transverse direction is also about 6 mm. The angle
~ of the longitudinally extending lateral walls of each
groove-like indentation which are inclined toward one another is
about 15°. The leg portions 31 and 32 need not extend exactly at
right angle to the surface of the clamping band but may form an
angle of about 5° perpendicular to the clamping band surface
(Figure 2).
Turning to the opposite end of the clamp structure of
Figures 1 through 8, the dimension i from the free end of the inner
band portion 10a to the edge 41~ of the support hook nearer the
free end of the inner band portion is about 48.6 mm. and the
spacing j from this edge 41 ~ to the center of the part-circular cut
43b is about 10 mm. while the spacing between the center of cut 43b
and the edge 41 ~ of the support hook 41 remote from free end of the
inner band portion 10a is about 10.2 mm. The diameter of the part-
circular cut 43b is 2 mm., and the distance k in the longitudinal
direction from the center of cut 43b to the end of the cut 43a is
about 4.7 mm. so that the distance 1 is 5.5 mm. The diameter of
the cut 43b is about 2 mm. and the radii of curvature in the
cut 43a are about 1 mm. The width m in the transverse direction of
each support hook 41 is about 5 mm. and the distance n of the
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CA 02206923 1997-06-04
center of the circular aperture 70 from the free end of the inner
band portion l0a is about 21 mm. The apertures 20a, 20b, 20d and
20e have an overall length p in the longitudinal direction of about
20 mm. and a width q of about 8 mm. with the corners rounded off
with a radius of curvature of about 2 mm. in the four corners
thereof. The length r in the longitudinal direction of the longer
aperture 20c is about 60 mm. with a width again of about 8 mm. and
the corners thereof rounded with a radius of curvature of 2 mm.
The mutual spacing between all apertures 20a, 20b, 200, 20d and 20e
is about 3 mm. As shown in Figure 4, the angle of inclination
of the inclined lateral band portions within the area of aperture
20a is about 15° whereby the length of the remaining lateral band
portions within the area of these apertures 20a through 20e is
about 2 mm. As shown in Figure 5 within the area of the inner
clamping band portion l0a of the remaining lateral band portions,
the angle ~ may be about 20°. As shown in Figure 2, the
dimension s is about 13.5 mm. and the dimension t about 8 mm. As
to the rest of the dimensions in the embodiment of Figures 1
through 8, they can be chosen to suit a particular application such
as thickness of the material which in the given embodiment is 0.8
mm. The same is true for the material used which in the particular
embodiment is AISI 304 stainless steel.
The embodiment of Figure 9 is similar to the embodiment of
Figures 1 through 8 except that the apertures 20a through 20e are
replaced by regularly spaced openings 120 whose diameter can be
selected at any desired value, depending on material to be used,
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' and thickness of the clamping band material to enhance the
effectiveness of the counterweight as mentioned above.
With respect to the clamp structure illustrated in Figure 12,
the improved guide-and-support hook 232 has a width A (Figure 15)
of about 4.4 mm. and a length B of about 5 mm. The part-circular
cut portion 232b~~ is formed with a radius R of about
2.5 mm. The flattened portion 232b has a length C (Figure 13) in
the longitudinal direction of about 0.8 mm. with a height D of
about 2.9 mm. The ramp-like inclined surface 232a forms an
angle ~'of about 27.7° (Figure 13). The centers of the radii of
curvature for the radii R2 are spaced from one another in the
transverse direction of the clamping band a distance E of about
4.38 mm. (Figure 14) with the radii of curvature R2 being about
1.3 mm. The distance of F between the radii of curvature for the
radii R3 in Figure 14 is about 0.98 mm. with the radii of curvature
R3 being 1.1 mm.
With respect to the pressed-out embossment 250 and the
tunnel-shaped member 235 illustrated in Figures 16 through 18, the
width M (Figure 16) in the longitudinal direction of the
reinforcement 250 is 2 mm., the embossed pressed-out height N of
the reinforcement (Figure 17) obtained by deep-drawing is about
0.3 mm., the radii of curvature R4 (Figure 17) are 1.82 mm. and the
radius of curvature R5 is 0.57 mm. The spacing P of the center
line of transversely extending portion 252 of the reinforcement 250
to the free end of the outer band portion 210b is about 2.5 mm.,
and the dimension O from the free end of the outer band portion
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2lob to the center of the semi-circular end portion of the two
lateral portions 251 of the reinforcement 250 is 5.5 mm. whereby
the center of the rounded-off ends of the lateral portions 251 are
spaced from one another in the transverse direction a distance Q of
about 9 mm. The tool-engaging surface 235 ~ is spaced from the free
end of the outer band portion 210b by a distance 8 of about 9 mm.
The height H of the tunnel-shaped member 235 (Figure 18) is about
3.2 mm., the spacing T in the transverse direction of the clamping
band by the centers of the radii of curvature for radii R6 is 5.8
mm. (Figure 18), and the radii of curvature R6 are about 0.5 mm.
The radius of curvature R7 is 1.7 mm. and the radius of curvature
R8 is 1.1 mm. The other dimensions of the clamp structure of
Figure 12 are readily ascertainable to a person skilled in the art
from the design criteria used with earless clamp structures
manufactured by and commercially available from the assignee of the
instant application. It should also be noted that all dimensions
are given in the flat condition of the clamping band.
To facilitate the task of selecting the proper counterweight,
a counterweight of standard size may be used, for example, of
rectangular configuration with the corners thereof chamfered off
and all of the same dimensions which offer different weights by the
number, size and locations of the openings 62 (Figure 20) provided
in the plate-like counterweight members 60. For example, the
plate-like member without any openings may have a weight of
grams, and with two openings 62 as shown in Figure 20 may have a
weight of 2 grams. Intermediate values can be attained by the
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number and size of such openings. The person selecting the
required counterweight can then assemble the required weight from
a number of such plate-like members. To hold the plate-like
members in a predetermined position relative to one another and to
the clamping band as well as rotating member, each plate-like
member is provided with a small pressed-out knub-like indentation
61 (Figures 20 and 21) which permits stacking the plate-like
members in proper position and retaining the stacked plate-like
members in such position.
In case the required weight for the counterweight is less than
the weight of the connection of the overlapping band portions and
the tightening means, it may be desirable to provide a balancing
clamp structure preassembled by means of a counterweight so as to
balance the clamp structure in itself. To that end, the plate-like
member representing the combined weight of the connecting and
tightening means may be permanently secured, for example, by
welding in the area opposite the connecting and tightening means
whereby only one or several small plate-like members need to be
selected to balance the rotating member by placing these plate-like
members in the correct position on the rotating member. By
providing the permanently secured counterweight with knub-like
indentations, the plate-like members) to compensate for the
imbalance in the rotating member may then be assembled in stacked
relationship to the permanently secured balancing weight. This
permits the use of a standard size of plate-like members though
also more than one standard size of plate-like members may be used
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provided they also include the pressed-out knub-like indentations
to permit stacking with plate-like members of different sizes.
Furthermore, standard sizes of different thickness may also be
provided as long as the plate-like members are always provided with
the means to enable stacking thereof. This not only facilitates
the work of the person charged with balancing the rotating member
but also keeps the assembled plate-like members in predetermined
relative position by preventing relative movement once in stacked
relationship. If the stack of plate-like members would become too
high in a radial direction as installed on the rotating member, it
is only necessary to use two clamp structures side-by-side to
divide the number of stacked plate-like members used with each
clamp structure.
While I have shown and described several embodiments in
accordance with the present invention, it is understood that the
same is not limited thereto but is susceptible of numerous changes
and modifications as known to those skilled in the art. For
example, if elastic stretchability is required in the longitudinal
direction of the clamp structure, it is also possible to utilize
one or more sections of concavely shaped lateral band portions
spaced by a window resembling an hourglass as disclosed in the
aforementioned copending application. Furthermore, according to a
preferred embodiment of this invention, in lieu of such sections,
one or more undulations may be provided in the clamping band of
suitable height and radius of curvature which are preferably
provided in the outer band portion near the beginning of the
overlap. Such tolerance-compensating undulations) would also
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compensate for differences in thickness of the counterweights and
would therefore obviate the need to manufacture different clamps
for different counterweight thicknesses. Additionally, any of the
features described in my aforementioned patents may be used if
desired. Furthermore, an auxiliary spring structure may also be
incorporated in each of the various embodiments of the clamp
structures described herein by utilizing the auxiliary spring
arrangements as disclosed in my prior U.B. Patents 5,111,555 and
5,138,747.
In lieu of a single wider clamping band with an "Oetiker" ear
provided with the double-reinforcing groove arrangement, it would
also be possible to use two side-by-side balancing arrangements,
each with predetermined counterweight and each constructed as
disclosed in the aforementioned British patent in order to increase
the weight range of the balancing arrangement. However, for cost
reasons and simplicity of installation, the arrangement in
accordance with this invention is preferable, especially in
applications of mass-produced items, such as drive shafts in the
automotive industry, in which ease of installation is of great
importance. Thus, while I have shown and described only several
embodiments of this invention, it is understood that the same is
not limited thereto but is susceptible of numerous changes and
modifications as known to those skilled in the art, and I therefore
do not wish to be limited to the details shown and described herein
but intend to cover all such changes and modifications as are
encompassed by the scope of the appended claims.
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