Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
:
Field of the Invention
The invention relates to a control lever assembly for ac-
tuating a control cable, particularly a cable capable of transmitting com-
pressive forces RS well as tensile forces, commonly called a push-pull cable,
which has applications in the marine control industry.
10 Prior Art 3
Control heads for controlling devices remotely have been
used for many years in the marine industry, for example, for controlling an
engine and gearbox of a marine vesseL Bowden cables have been used
15 successfully in certain applications, the Bowden cable having a sheath and a
cable core slidable within the sheath. The core is relatively flexible and thus
is prone to buckling when subjected to compressive forces, and preferably this
type of cable is used only in situations where it is subjected to a tensile force.
The limitations of the Bowden cable to transmitting force in
one direction, namely as a tensile force, have been recognized for many years
and now a cable having a stiffer core has been developed, such cable being
known as a push-pull cable which is capable of carrying a degree of
compressive forces before buckling when extending from an end of the sheath
25 and being unsupported by the sheath. The tendency of a push-pull cable to
buckle under compressive force is proportional to the length of usupported
coPe extending from the sheath, and also, to some extent, the alignment of
the sheath with the core itself and the line of action and direction of the
compressive force applied to the core. Commonly, a core of a cable is
30 anchored to a rotatable member at a position spaced from the axis of rotationthereof so that as the member is rotated the core anchoring means, and with
it the core, is subjected to swinging and lateral movement which shifts the
cable core from a position aligned with an adjacent end portion of the sheath.
To reduce buckling and binding tendencies of the sheath on the core, the
35 adjacent end of the sheath swivels to accomodate the lateral swinging of the
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core. This is attained by several different methods in the prior art, for
example, see United States Patent 2, 975,653 (Morse) and United States
Patent #3,101,821 ~Henry). In both of these prior art structures, an adjacent
end portion of the sheath enclosing the core is swung laterally by direct
5 movement of the core itself acting on the sheath, which swivels on a sheath
swivelling connection. Whilst this arrangement is satisfactory for some
applications, where there is a relatively long length of unsupported core
extending from the outer portion of the sheath to the core connection and a
compressive force is applied to the core, as in the pushing mode, buckling of
10 the core can result due to the inability of the sheath to follow wide swings of
the core and to become aligne~ therewith.
SUMMARY OF THE INVENTION
The difficulties and disadvantages of the prior art are re-
duced by providing a control lever assembly according to the invention in
which the sheath of the control cable has an adjacent end portion which is
swivellable positively by means other than the lateral force of the core acting
20 on the sheath itself. As the anchored end of the core swings through an arc
due to rotation of the lever, a positive connection between the lever and the
sheath swivels the adjacent end portion of the sheath to accomodate the
lateral movement to maintain approximate alignment of the sheath with the
core without excessive lateral forces acting on the core, thus reducing a
25 tendency of the unsupported core to buckle under compressive forces.
A control lever assembly according to the invention is for
actuating a control cable having a cable sheath and a cable core slidable
within the sheath, the assembly having a body, a lever and a core anchoring
30 means. The lever is journaUed for rotation relative to the body about a lever axis and the core anchoring means cooperates with the lever to rotate
therewith relative to the body so as to be subjected to relative displacement
during such rotation. The core anchoring means also is adapted to anchor one
end of the core of the control cable. The assembly is further characterized
35 by a sheath retaining means and a connecting means. The sheath retaining
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means cooperates with the sheath to retain a portion of the sheath to restrict
axial movement of the sheath following actuation of the cable. The
connecting means, which is structurally independent of the control cable,
cooperates with the sheath retaining means to swivel the sheath retaining
5 means in response to rotation of the core anchoring means. This causes the
sheath retaining means to swivel to accomodate the relative displacement of
the core anchoring means to maintain approximate alignment of the sheath
with the core.
A detailed disclosure following, related to drawings, des-
cribes a preferred embodiment of the invention which is capable of expression
in structure other than that described and illustrated.
15 DESCRIPTION OF THE DRAWINGS
Figure 1 is a simplified fragmented side elevation of a control lever
assembly according to the invention, some portions being
shown in section or in broken outline,
Figure 2 is a simplified fragmented end elevation of the assembly of
Figure 1,
Figs. 3, 4 ~ 5 are simplified sequence diagrams showing the control lever
assembly in a central position, an intermediate position and
an extreme outer position respectively, showing progressive
swivelling of a sheath retaining means.
30 DETAILED DISCLOSURE
Figures 1 and 2
A control lever assembly 10 according to the invention has a
35 body 12 and a manually actuated lever 14 extending from a lever spindle 15.
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The spindle is journalled relative to the body in a pair of spaced journals 16
for rotation relative to the body about a lever axis 18. The body is adapted to
be secured to a table surface 21, and carries a cable support 23 extending
below the table to a lower end 25.
A control cable 27 has a cable sheath 29 and a cable core 30
slidable within the sheath, the cable core being sufficiently stiff to permit
transmission of compression forces relative to the sheath, and is commonly
called a push-pull cable. A sheath retainer member 32 is journalled on a bolt
34 at the lower end 25 so that the retainer member is journalled for rotation
relative to the body about a retainer axis 36 whîch is disposed parallel to the
lever axis. This is accomplished by means of a generally U-shaped sheath
clamp 38 secured by bolts 40 to the retainer member 32 so as to essentially
prevent longitudinal movement of the sheath 29 relative to the retainer
member 32. Thus the retainer member 32 and the clamp 38 and associated
structure serve as sheath retaining means cooperating with the sheath to
retain a portion of the sheath to restrict axial movement of the sheath
following actuation of the cable.
A rotatable member 43 is disc-like and is secured to the
lever spindle 15, and thus cooperates with the lever to rotate therewith. A
support member 45 is securable by three screws, severally 47, to the support
member so as to rotate therewith and to provide a clearance 49 between the
rotatable and support members. The support member 45 is a four-sided plate-
like member which has a series of axially disposed recesses, severally 52,
which face inwardly into the clearance 49 and are aligned with a similar
series of axially disposed recesses 54 in the rotatable member 43. The
rotatable member has an outer cam surface 56 with which a cam follower 58
cooperates to actuate a limit switch 80 so as to control electrical devices,
not shown, as required. Clearly, other structures can cooperate with the
rotatable member for particular functions. A cable fitting 63 is fitted at an
outer end of the cable core 30 and has a cylindrical bore therein to receive a
spindle 65. The spindle 65 has opposite ends carried in a pair of the aligned
recesses 52 and 54, and fits in the clearance between the members 43 and 45.
Thus, an intermediate portion of the spindle journals the cable fitting
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between the members and serves as a journalling means which is a cylindrical
element cooperating with the cable fitting and journalled in the aligned
recesses. Clearly, the cable fitting could have other means to cooperate with
the members 43 and 45 in which only one OI the members 43 or 45 requires a
5 recess. The rotatable member 43, the support member 45, the spindle 65 and
the cable fitting 63 serve &S core anchoring means 66 cooperating with the
lever to rotate therewith relative to the body so as to be subjected to relativedisplacement or lateral movement during such rotation. It can be seen that
the core anchoring means is adapted to anchor one end of the core of the
10 control cable and clearly, equivalent structures can be devised. A particularadvantage of the core ancho~ing means as described herein is that the cable
can be secured relative to the lever means by a simple structure which does
not require cotter pins, bolts with locking nuts, etc. to retain the end of the
cable. Also, the anchoring means is a relatively compact structure which, by
15 providing the series of aligned recesses, permits easy adjustment of the
moment arm or lever effect of the core anchoring means relative to the lever
AxiS. As shown, the spindle 65 is fitted in the second pair of recesses of the
series, and thus provides a relatively large cable core axial movement for a
particular rotation of the lever, with a correspondingly large relative
20 displacement or lateral movement of the core anchoring means 66.
The structure as above described is adequate for applying
tensile force to the core 30 of the cable because the sheath retainer member
32 could be made to be free to swivel to some extent about the retainer axis
25 36 in response to lateral movement or relative displacement of the outer end
of the core or the core anchoring means which occurs when the lever rotates
more than a few degrees. A full range of movement of the lever of between
50 and 60 on either side of an intermediate or central position as shown in
Figures 1 and 2 would result in a corresponding swinging of the sheath up to
30 about 15 on either side of an aligned central position, as shown in Figures 3
through 5.
However, if the above structure were used to apply com-
pressive forces to the core of the cable, it is likely that the adjacent end of
35 the sheath would not be sufficiently aligned with the core or anchoring means
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to avoid excessive out of alignment forces on the core that would likely result
in buckling of the core followed by permanent bending or breakage. The
present invention is particularly adapted to essentially eliminate problems
that result in the buckling of the core under compressive forces that occur in
5 a pushing mode. This is accomplished by a simple structure which extends
between the lever and sheath retaining means to positively align the adjacent
end of the sheath with the unsupported portion of the core, as follows.
A circular cam 67 has a cam center 69 disposed laterally of
10 a longitudinal plane 71 passing through the lever axis 18 and the retainer axis
36 when the lev~sr is in an intérmediate position thereof as shown. In effect,
the cam center 69 is disposed in a transverse plane 73 which is disposed
approximately at right angles to the longitudinal plane 71 when the lever is in
the intermediate position. The cam means is disposed on a face of the
15 support member 45, and is mounted eccentrically relative to the lever axis 18for rotation with the core anchoring means so that rotation of the cam means
results in a circular movement of the cam center. It can be seen that
rotation of the cam means results in movement of the cam center out of the
transverse plane 73, which movement has a component parallel to the
20 longitudinal plane 71, as will be described. A connecting link 76 has an upper
end having a circuler recess 77 complementary to the circular cam 67 and a
lower end connected by a hinge pin 79 to the sheath retainer member 32. The
connecting link 76 thus serves as a cam follower having adjacent one end
thereof a circular recess complementary to the circular cam to be accepted
25 thereon and is connected to the sheath retaining member adjacent an opposite
end thereof.
OPERATION
In Figures 1 through 3, the lever 14 is shown in a central or
intermediate position midway between two extreme positions and the control
cable 27 is aligned with the longitudinal plane 71 and the spindle 65 of the
cable anchoring means. In Figure 4, the lever 14 is swung through an angle 84,
35 of about 30, to a position shown at 14.1 in which the support means 45 and
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the spindle 65 have assumed corresponding displaced positions ~5.1 and 65.1
disposed laterally of the longitudinal plane 71. The cam center 69 has swung
through a similar angle 84 to a raised position 69.1 which results in a
corresponding upward movement of the upper end of the connecting link 76
5 which results in a corresponding rotation of the sheath retainer member 32 in
direction of an arrow 86. Rotation of the retainer member 32 causes a
corresponding swinging of the adjacent end of the control cable 27, so that an
axis 88 of the control cable which is aligned with a portion of the core 30
leaving the she~th, passes closely adjacent, or intercepts, the spindle 65.
10 Because the spindle 65 is fitted in the second recess of the series of recesses,
the axis 88 passes closely thereto, as it would pass through a position about
midway between the series of four recesses. It can therefore be seen that the
connecting link 76 serves as a portion of a connecting means 89 which is
structurally independent of the control cable and cooperates with the sheath
15 retaining means, ie. the member 32, and the core anchoring means to swivel
the sheath retaining means in response to rotation of the core anchoring
means. Thus, the sheath retaining means swivels to accomodate the lateral
movement or relative displacement of the core anchoring means 66 to
maintain approximate alignment of the sheath with the core. It can be seen
20 that, in this position, if the direction of rotation of the lever 14 is reversed so
that a compressive force is applied to the core of the cable, the core
maintains substantial alignment with the sheath as the support member 45
swings back towards the plane 71. It can be seen that the connecting means
89 also includes a driver means, n~mely the cam means, which is journalled
25 for rotation with the core anchoring means, an-3 also a driven means, namely
the cam follower or connecting link 76, which cooperates with the driver
means and the retainer member so that lateral movement or relative
displacement of the core anchoring means is reflected approximately by a
corresponding rotation of the retainer member about the retainer axis. In
30 effect, the connecting link 76 or cam follower provides Q rigid positive
connection between the retainer member and the cam to reflect movement of
the cam in either direction, and thus, eliminates some problems of the prior
art where the necessary lateral swivelling force is normally applied to the
sheath itself to cause- the swinging of the sheath. With some earlier
3S structures, the lateral swivelling force would tend to aggravate the tendency
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of the core to buckle under compressive loads.
Referring to Figure 5, the lever 14 is swung through an angle
90 to assume an extreme position 14.2, between 50 and 60 from the central
5 position. This produces a corresponding rotation of the support means to an
extreme position 45.2 in which the spindle 65 assumes an extreme position
65.2. The cam center 69 assumes an extreme raised position 69.2 after
swinging through the angle 90 and this causes a corresponding additional
upwards movement of the connecting link 76 to further rotate the sheath
10 retainer member in direction of the arrow 86. This rotation produces an
additional swivelling OI the sheath 27 so that the axis 88 of the core 30 is
maintained to be substantially aligned with the core anchoring means on the
spindle 65.
It is assumed that the central position of the lever, as shown
in Pigure 3, is in fact an intermediate position of the lever disposed equally
between two outer extreme positions. The description above discusses
swinging of the lever, with a corresponding rotation of the sheath anchoring
means to one extreme position, and by inspection, it can be seen that rotation
ao of the lever in the opposite direction to an angle equal to the angle 90 would
result in a corresponding swinging of the retainer member 32 in an opposite
direction, so as to maintain alignment of the core with the core anchoring
means for essentially all positions of the lever.
