Railways – Way suspension
Reexamination Certificate
2000-02-09
2001-10-16
Le, Mark T. (Department: 3617)
Railways
Way suspension
Reexamination Certificate
active
06302030
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention pertains to elevated cableway systems used in mass transit systems and the like, and, more particularly, to an improved cableway for such systems.
2. Description of the Prior Art
Many types of elevated cableway systems have been used in or proposed for mass transit systems. One such system is disclosed and claimed in U.S. Pat. No. 4,069,765 issued Jan. 24, 1978 to Gerhard Müller . This system is neither a suspension, or cable stayed bridge nor an aerial tramway. Consequently, not all standard design criteria are necessarily applicable to the system in the Müller '765 patent.
Thus the Müller '765 patent discloses a non-standard approach and
FIGS. 1-5
of the present application correspond to
FIGS. 3-7
of the Müller '765 patent.
FIG. 1
illustrates in gross an elevated cableway system
10
in which vehicle
12
travels along track cable systems
14
suspended from catenary, or support cable
16
. As shown in
FIGS. 2-3
and
5
, track cable systems
14
comprises locked-coil steel cables
14
a-d
and catenary cable system
16
comprises locked-coil steel cables
16
a-b.
Returning to
FIG. 1
, a plurality of pylons
18
elevate and support track cable systems
14
and catenary cable system
16
between the termini
20
of system
10
. Track cable systems
14
and catenary cable system
16
are preferably anchored to ground
19
to sustain horizontal cable forces and transmit them to ground
19
.
One of Müller's basic approaches is illustrated in
FIGS. 1-2
. Stress loads associated with the “sag” in track cable systems
14
and catenary cable system
16
caused by the weight of vehicle
12
were a problem for cableway systems at the time Müller filed the '765 patent application as shown in FIG.
1
. Müller proposed, as disclosed in the '765 patent, to address these problems by pre-tensioning, or pre-stressing, track cable systems
14
so that track cable systems
14
leveled under the weight of vehicle
12
as shown in FIG.
1
.
Part of Müller's proposed design included new cross-ties
15
and hangers, or spacers,
7
for suspending track cable systems
14
from catenary cable system
16
. These cross-ties
15
and hangers
7
, which were new at the time, are illustrated in
FIGS. 2-3
. Through this suspension system, track cable systems
14
were tensioned as described above and, consequently, “bowed” upward when not weighted by vehicle
12
. This approach has worked well and is incorporated in the present invention as set forth below.
Müller also proposed tying track cable systems
14
and catenary cable system
16
together between pylons
18
at points
22
as shown in FIG.
4
. Müller tied the cables with force equalization plate
24
, in cooperation with clamping plate
26
and wedges
28
. Force equalization plate
24
also improved the distribution of load stresses in the cableway system and, in combination with tensioning track cable systems
14
, substantially advanced the art.
Müller also adopted the pylon structure earlier disclosed in U.S. Pat. No. 3,753,406. As set forth in column 1, line 65 to column 2, line 3 of the '765 patent, it was thought the pylons in such a system must be “stiff”. It was though that “self-aligning” or “self-adjusting” pylons would introduce undesirable longitudinal shifting between the catenary and track cables. However, we now know that “self-aligning” or “self-adjusting” pylons produce substantial design benefits provided measures are taken to minimize or eliminate longitudinal shifting.
Some problems also appeared in implementing Müller's design despite its great advance over the art. For instance:
(1) catenary cable system
16
was strung over rollers on the top of pylons
18
and began to wear from the movement across the rollers as vehicle
12
traversed the cableway;
(2) the design of the equalizer plate
24
could also cause problems by kinking cable elements
16
a-b,
and
14
a-d,
under some circumstances; and
(3) cable elements
14
a-d
were required to have upper surfaces engageable by the wheels of the vehicle because the equalizer plate did not provide for such engagement.
It further came to be realized that load stresses could be better distributed through redesign of the force equalizing assembly as well as the hangers and cross-ties, particularly in light of the new pylon designs.
U.S. Pat. No. 4,264,996 by Baltensperger and Pfister. describes a suspended railway system with towers that support a catenary cable atop the towers and support track cables with a “stressing beam” that is pivotally connected to the towers. The '996 system is, however, distinguishably less capable than the present invention. For instance, the '996 patent fails to grasp the catenary cable at the support on top of the tower. Therefore, as described in the '996 patent, the cable is allowed to slip in the notches of the support. This slippage will inevitably cause wear on the cables.
Additionally, while the stressing beam gives some measure of weight redistribution at the track cable support, the fact that there is only one beam and the fact that the beam merely pivots about a single point ensures that the impact with the support of a vehicle passing over the support will not be substantially lessened. When weight is applied to one end of the beam, the other end of the beam necessarily must tilt upwardly thereby creating a ramp for a vehicle traversing the track to climb. With only a single beam, the tilt of the beam cannot be lessened until the vehicle passes each point along the beam. If the beam had secondary and tertiary beams connected to it as the present invention does, the moment about the central pivot point could be lessened in advance of the vehicle. With secondary and tertiary beams, the point of applied load is the point where the secondary beam attaches to the main beam, not the point the vehicle is passing.
It is therefore a feature of this invention that it provides an improved pylon design for elevated cableway systems.
It is furthermore a feature of this invention that the improved pylon design reduces wear on the catenary cable system by not allowing the catenary cable system to slide or roll directly on the top of the pylon.
It is furthermore a feature of this invention that the improved pylon includes a new, deflecting upper saddle to support the catenary cable system while relieving stresses imposed on the catenary cable system by deflecting under load applied by the vehicle traversing the track cable system.
It is a still further feature of this invention that the improved pylon includes an improved, pivotable lower saddle to better transmit forces and distribute load stresses through the cableway system as the vehicle traverses the cableway.
It is furthermore a feature of this invention that load stresses are distributed through improved hanger and spacer designs.
It is still furthermore a feature of this invention that it provides an improved cableway system with greater lateral support for the union between the catenary and track cable systems by providing improved force equalizing assemblies.
It is still furthermore a feature of this invention that it provides an alternate force equalizing assembly that reduces wear on the catenary cable system and the track cable systems by allowing the cables to controllably yield relative to one another as force is transferred between them.
SUMMARY OF THE INVENTION
The features described above, as well as other features and advantages, are provided by an improved cableway system that includes a pylon, an upper saddle, and a lower saddle. The pylon includes a base pylon, and the lower saddle is mounted to the base pylon from which a track cable may be strung. The upper saddle, from which a catenary cable system may be strung, is movably mounted to the base pylon to deflect in response to the weight of a vehicle traversing the track cable systems.
The improved pylon also includes in some embodiments a new lower saddle including a main beam pivotally mounted
Lamoreaux Ben
Pugin Andre O.
Aerobus International Inc.
Fulbright & Jaworski L.L.P.
Le Mark T.
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