Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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ZIPLINE BRAKING AND MOTION-ARREST SYSTEM
Technical Field
[0001] This invention relates to a zipline braking system for
braking the arrival of a zipline rider at a landing platform and arresting
the rider's motion to retain the rider at the landing platform.
Bac round
[0002] "Ziplines" are gravity-based cable rides generally used to
transport people for various purposes including recreational thrill rides,
forest canopy tours, challenge courses and rescue operations. A typical
zipline includes a stranded steel wire cable or fibre rope suspended
between two supports, platforms at each support for launching and
landing riders, pulley blocks and harnesses to support and transport
riders along the cable.
[0003] For example, Figure 1 depicts a zipline system in which
wire rope main cable 4 is suspended between supports lA, 1B which
may be constructed of wood, steel, aluminum or any other structurally
suitable material. Trees or boulders may alternatively function as
supports 1 A; 1 B . A launch platform 2A is constructed on or surround-
ing support lA, and a landing platform 2B is constructed on or sur-
rounding support 1B. Either or both of platforms 2A, 2B may be (and
typically are) fixed or mounted at elevated locations on supports 1 A, 1 B
respectively. Each platform 2A, 2B is equipped with a ramp or steps
3A, 3B respectively to assist in launching and landing of riders as
explained below. Although not shown, platforms 2A, 2B are typically
also equipped with suitable safety railings and access control gates.
Platforms 2A, 2B may be suspended relative to supports lA, 1B to
facilitate raising or lowering of platforms 2A, 2B (e.g. via suitable
motorized winches) in order to periodically adjust the tension of cable
4.
[0004] Rider 7 begins by donning a harness 6 supplied by the
zipline operator. Harness 6 includes a short tether which is securely
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fastened to a pulley block 5. After donning harness 6, rider 7 ascends
to launch platform 2A, where the zipline operator's personnel couple
pulley block 5 to cable 4, such that pulley block 5 will roll smoothly
along cable 4. Rider 7 descends launch steps 3A and is released under
the control of the zipline operator's personnel. More particularly,
pulley block 5 rolls along cable 4 toward landing platform 2B (i.e. from
right to left as viewed in Figure 1 ) with rider 7 suspended beneath cable
4 by harness 6.
[0005] Rider 7 must reach and be braked and arrested at landing
platform 2B. If rider 7 is not properly braked upon arrival at landing
platform 2B, the moving rider may collide with support 1B, with land-
ing platform 2B or with persons or objects on landing platform 2B. If
rider 7's motion is not properly arrested upon arrival at landing plat-
form 2B, rider 7 may roll back down to the nadir of cable 4. Similarly,
if rider 7 is not carried along cable 4 with sufficient velocity, rider 7
may slow down, stop short of landing platform 2B, and roll back down
to the nadir of cable 4. In either case, the zipline operator's personnel
must rescue rider 7 from the nadir of cable 4. The rescue technique is
well known and straightforward, and need not be described here. But,
to avoid potentially time-consuming and somewhat labour intensive
rescue operations, the slope of cable 4 (the vertical distance between
platforms 2A, 2B), the cable's sag (the vertical distance between cable 4
at mid-span and a chord drawn between supports lA, 1B) and the
cable's tension are preferably adjusted to achieve a reasonable transit
time at sufficient velocity along cable 4 to enable rider 7 to reach
landing platform 2B.
[0006 The prior art has evolved various zipline braking and
motion-arrest techniques. In some cases (e.g. if the landing platform is
between the supports, at the nadir of the cable) no braking system is
needed-the rider is intentionally allowed to roll back down to and stop
at the nadir of the cable, and dismounts there. Another brakeless
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technique requires the zipline operator's personnel to physically catch
and hold the rider upon arrival at the landing platform. Some zipline
operators attach a second "tag line" cable, separate from the main
zipline cable, to the rider's support pulley block, for braking purposes.
Other operators provide automatic and/or rider-controlled brakes.
[0~7] This invention provides a braking system for braking a
zipline rider upon arrival at a landing platform, for arresting the rider's
motion to retain the rider at the landing platform and for hauling the
rider up to the landing platform. Besides enhancing safety, this allows
the zipline operator's personnel to deal with other zipline operational
aspects.
Brief Description of Drawings
[0008] Figure 1 is an isometric view of a zipline showing the
supports, the launch and landing platforms, the main cable and a brak-
ing system in accordance with the invention.
[0009] Figure 2 is an isometric view of the landing platform
showing the relationship between the braking block on the main cable,
the structure supporting the brake line pulley, the braking device on the
support tower, the anti-rollback device on the support tower and the
haul-up line.
[0010] Figure 3 is a detailed isometric view of a braking block in
accordance with a first embodiment of the invention.
[0011] Figure 4A is an isometric view of a braking block in
accordance with a second embodiment of the invention, showing a
pulley block about to latchingly engage the braking block. Figure 4B
depicts the Figure 4A apparatus after the pulley block latchingly en
gages the braking block.
[0012] Figure 5 is an isometric view depicting an alternate pulley
block for latchingly engaging the braking block shown in Figures 4A
and 4B.
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[0013] Figure 6A is a schematic isometric view of a braking block
in accordance with a third embodiment of the invention, showing a
pulley block about to latchingly engage the braking block.
[0014] Figure 6B is a schematic isometric view of a braking block
in accordance with a third embodiment of the invention, showing a
pulley block about to latchingly engage the braking block.
[0015] Figure 7 is a schematic isometric view of a braking block
in accordance with a fourth embodiment of the invention, showing a
pulley block about to latchingly engage the braking block.
[0016] Figure 8 is a schematic isometric view of a braking block
in accordance with a fifth embodiment of the invention, showing a
pulley block about to latchingly engage the braking block.
Description
[0017] Throughout the following description, specific details are
set forth in order to provide a more thorough understanding of the
invention. However, the invention may be practiced without these
particulars. In other instances, well known elements have not been
shown or described in detail to avoid unnecessarily obscuring the
present invention. Accordingly, the specification and drawings are to
be regarded in an illustrative, rather than in a restrictive sense. As used
herein and as indicated by double-headed arrows in Figures 2, 4A and
5, "rearward," "rearwardly," "rearwardmost" and "forward," "for-
wardly," "forwardmost" mean directions which are respectively longi-
tudinally closer to and farther from a landing platform approached by a
rider traversing cable 4. "Inward" and "outward" mean directions
which are respectively laterally closer to and farther from cable 4.
[0018] Figures 1, 2 and 3 depict an embodiment of the invention,
including braking block 11, installed at the previously-described landing
platform 2B. As best seen in Figure 3, four pulleys 19 are rotatably
mounted within a first frame 18 formed of a pair of spaced-apart metal
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plates. Two of pulleys 19 are longitudinally aligned to rotatably engage
main cable 4 from above. The other two of pulleys 19 are longitudi-
nally aligned to rotatably engage the underside of cable 4. (In some
cases in may be sufficient to provide only three pulleys 19, with two
pulleys engaging cable 4 from above and the third pulley engaging the
underside of cable 4.) First frame 18 is welded or otherwise suitably
fastened to a second metal plate frame 13, which forms a "V" longitu-
dinally aligned with and straddling cable 4, the narrow, rearward end of
the "V" being located closest to support 1B. Pulleys 19 permit longitu-
dinal rolling movement of braking block 11 (which incorporates frames
18, 13) in either direction along cable 4.
[0019] Resilient (e.g. urethane-lined) bumper block 17 is mounted
on second frame 13, forwardly of first frame 18 and above cable 4.
Bail 16 couples bumper block 17 to braking line 10, which is routed
through a system of pulleys 9 to braking device 12 and to anti-rollback
device 22 fixed on support 1B. A pair of struts 8 are pivotally attached
to opposed sides of landing platform 2B. Crossbar 26 extends between
the forward ends of struts 8, above main cable 4 and forwardly of
braking block 11. One of pulleys 9 is rotatably mounted on crossbar
26 . The remaining pulleys 9 are rotatably mounted on support 1 B .
Bracket 20 is welded or otherwise suitably fastened to the narrow "V"
end of second frame 13, beneath cable 4, to provide a connecting point
for haul-up line 27. Braking device 12 may be a belaying device of the
type commonly used by mountain climbers, or any one of a brake lever,
a drum brake, or brake caliper. In some cases there may be no braking
device per se, for example if the force exerted by a human manipulating
braking line 10 and haul-up line 27 is sufficient to brake rider 7 to a
stop. Anti-rollback device 22 may be a cam cleat of the type commonly
used to secure ropes on pleasure boats or a self jamming pulley such as
those available from PETZL~M America of Clearfield, UT under the
trademarks Pro-Traxion'~ or Mini-TraxionTM.
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[0020] A self closing, one-way latch 14 is provided at the wider,
open forward end of second frame 13 to form a corral 21 within second
frame 13 between bumper 17 and latch 14. Latch 14 may be formed by
fixing a pair of flexible, first and second capture plates 25A, 25B at the
wider, open forward end of second frame 13, such that plates 25A, 25B
form another "V" longitudinally aligned with and straddling cable 4, the
narrow, rearward end of the "V" again being located closest to support
1B. Because capture plates 25A, 25B are formed of a flexible material
(e.g. plastic or another suitable flexible material) the rearward ends of
plates 25A, 25B are inherently inwardly biased toward one another, on
opposite sides of cable 4. Alternatively, self closing one-way latch 14
may be formed by providing a pair of hinged and/or spring-biased
plates at the wider, open end of second frame 13 (in which case plates
25A, 25B need not be flexible).
[0021] Care is taken to dimension the above-described components
of braking block 11 so that the overall centre of gravity of braking
block 11 is below main cable 4.
[0022] In operation of the embodiment of Figures 1, 2 and 3, rider
7's pulley block 5 rolls rearwardly along cable 4 and collides with latch
14. The collision force drives (i.e. bends or deforms) flexible plates
25A, 25B outwardly away from cable 4, allowing pulley block 5 to roll
through latch 14 into corral 21. As soon as pulley block 5 rolls past the
rearwardmost ends of plates 25A, 25B those plates flex back into their
original position, closing latch 14 upon cable 4 and thereby preventing
pulley block 5 from rolling forwardly back through latch 14. After
rolling past the rearwardmost ends of plates 25A, 25B as aforesaid,
pulley block 5 continues rolling rearwardly along cable 4, through
corral 21, until pulley block 5 collides with bumper block 17. The
latter collision stops rider 7 by transferring the rider's kinetic energy
through bumper block 17, bail 16 and braking line 10 to braking device
12.
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[0023] The zipline operator's personnel manipulate braking line 10
and haul-up line 27 to brake rider 7 to a stop and manoeuver rider 7
onto landing platform 2B. For example, after coming to a stop, rider 7
may be unable to reach steps 3B on landing platform 2B, in which case
the zipline operator's personnel manipulate haul-up line 2? to haul
braking block 11 rearwardly along cable 4 toward support 1B. Since
the rider's pulley block 5 is captured within braking block 11, such
action simultaneously hauls the rider's pulley block 5 and the harness-
suspended rider along cable 4 toward support 1 B, and is continued until
the rider reaches a secure dismount position relative to landing platform
2B at which pulley block 5 can be decoupled from cable 4. During this
procedure, the need for the operator's personnel to maintain continuous
force on haul-up line 27 to prevent rider 7 and braking block 11 from
rolling back down main cable 4 is obviated by anti-rollback device 22.
[0024] Figures 4A and 4B depict an alternate embodiment of the
invention in which four pulleys 30 are rotatably mounted between metal
plates 32, 34 with the aid of axle bolts 36 to form a braking block frame
44. More particularly, two of pulleys 30 are longitudinally aligned to
rotatably engage main cable 4 from above and another two of pulleys 30
(not shown) are longitudinally aligned to rotatably engage the underside
of cable 4. (In some cases in may be sufficient to provide only three
pulleys 30, with two pulleys engaging cable 4 from above and the third
pulley engaging the underside of cable 4.) Pulleys 30 permit longitudi-
nal rolling movement of braking block frame 44 in either direction
along cable 4.
[0025] Machine screws or bolts 46 and washers 48 fasten resilient
(e.g. urethane) bumper block 50 to bars 52, 54 which are respectively
attached (e.g. welded or otherwise suitably fastened) to the forward
ends of plates 32, 34 respectively, above cable 4. A first pair of
spaced-apart, vertically aligned flanges 56, 58 are attached (e. g, welded
or otherwise suitably fastened) to the outward side of plate 34. A
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second pair of spaced-apart, vertically aligned flanges (not visible in
Figures 4A, 4B) are formed or attached (e.g. welded or otherwise
suitably fastened) to the outward side of plate 32. Bolts 64 pivotally
connect inwardly angled flange 74 provided on the rearward end of first
capture plate 76 between flanges 56, 58 on one side of cable 4. Al-
though not visible in Figure 4A or 4B, a similar arrangement is pro-
vided on the opposite side of cable 4 to pivotally connect second capture
plate 90 between the vertically aligned flanges provided on plate 32.
Spring 92 is connected in tension between a selected pair of apertures
94 provided in each of capture plates ?6, 90 to normally bias plates 76,
90 inwardly toward one another on opposite sides of cable 4. The
biasing force can be selectably adjusted by reconnecting spring 92
between a different selected pair of apertures 94. If desired, more than
one spring can be connected between selected pairs of apertures 94.
[0026] Capture plates 76, 90 have inwardly extending forward
ends 96, 98 respectively, which spring 92 normally biases inwardly
toward one another on opposite sides of cable 4. When viewed from
above, capture plates 76, 90 accordingly form a "V" longitudinally
aligned with and straddling cable 4, the "V" having a narrow forward
end and a wide rearward end, with the wide rearward end of the "V"
located closer to the landing platform than the narrow forward end of
the "V" . Care is taken to dimension the above-described components
of braking block frame 44 and capture plates 76, 90 so that the overall
centre of gravity of braking block frame 44 is below main cable 4.
[0027] Latch plate 100 is fastened atop pulley block 5 by rivets
102. Plate 100 is rearwardly tapered toward its rearward end 106 (i.e.
the end of plate 100 closest to braking block frame 44). Outwardly
extending flanges 108, 110 axe provided on the outward sides of plate
100 to define opposed notches 112, 114 on the respective outward sides
of plate 100. Shackle 116 connects one end of braking line 10 to the
upper, forward ends of braking block frame 44. As in the case of the
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embodiment of Figures 1, 2 and 3, braking line 10 is routed through the
aforementioned system of pulleys 9 to braking device 12 and to
anti-rollback device 22 fixed on support 1B.
[0028] In operation of the Figure 4A and 4B embodiment, rider
7's pulley block 5 rolls along cable 4 until latch plate 100's tapered
rearward end 106 collides with the inwardly biased forward ends 96, 98
of capture plates 76, 90. The collision position of latch plate 100 is
shown in solid lines in Figure 4A. The collision force overcomes the
tension of spring (or springs) 92 and drives capture plates 76, 90
outwardly away from cable 4 as indicated by arrow 118, allowing
pulley block 5 and latch plate 100 to roll rearwardly of the forward ends
96, 98 of capture plates 76, 90. As soon as the forwardmost portions of
flanges 108, 110 are carried rearwardly of the inwardly biased forward
ends 96, 98 of capture plates 76, 90 spring 92 draws capture plates 76,
90 inwardly toward cable 4 as indicated by arrow 119 (Figure 4B),
positioning forward ends 96, 98 of capture plates 76, 90 forwardly of
notches 112, 114 respectively. Any subsequent forward motion of
pulley block 5 along cable 4 accordingly engages forward ends 96, 98
within notches 112, 114 preventing further forward motion of pulley
block 5 and rider 7 along cable 4. Capture plates 76, 90 and spring 92
thus form a self closing one-way latch which, when closed upon latch
plate 100 as aforesaid, prevents pulley block 5 from rolling forwardly
along cable 4.
[0029] After rolling past forward ends 96, 98 of capture plates 76,
90 as aforesaid, pulley block 5 continues rolling rearwardly along cable
4, until pulley block 5 collides with bumper block 50 (i.e. latch plate
100 is carried by pulley block 5 into the position shown in dashed lines
in Figure 4A). The latter collision stops rider 7 by transferring the
rider's kinetic energy through bumper block 50 and braking line 10 to
braking device 12. The zipline operator's personnel then manipulate
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braking line 10 and haul-up line 27 to brake rider 7 to a stop and
manoeuver rider 7 onto landing platform 2B as previously explained.
[0030] Figure 5 depicts an alternate pulley block 120 for latchingly
engaging the braking block shown in Figures 4A and 4B. Rearwardly
and outwardly extending hook plates 122, 124 are provided on the
outward sides of pulley block 120 to define opposed notches 126, 128
on the respective outward sides of pulley block 120. In operation of the
Figure 5 embodiment, pulley block 120 rolls rearwardly along cable 4
until the rearwardmost ends of hook plates 122, 124 collide with the in-
wardly biased forward ends 96, 98 of capture plates 76, 90. The
collision force overcomes the tension of spring (or springs) 92 and
drives capture plates 76, 90 outwardly away from cable 4, allowing
pulley block 120 to roll rearwardly of the forward ends 96, 98 of
capture plates 76, 90. As soon as the opposed outward ends of hook
plates 122, 124 are carried rearwardly of the inwardly biased forward
ends 96, 98 of capture plates 76, 90 spring 92 draws capture plates 76,
90 inwardly toward cable 4, positioning forward ends 96, 98 of capture
plates 76, 90 forwardly of notches 126, 128 respectively. Any subse-
quent forward motion of pulley block 120 along cable 4 accordingly
engages forward ends 96, 98 within notches 126, 128 preventing further
forward motion of pulley block 120 and rider 7 along cable 4. Capture
plates 76, 90 and spring 92 thus form a self closing one-way latch
which, when closed upon pulley block 120 as aforesaid, prevents pulley
block 120 from rolling forwardly along cable 4. After rolling past for-
ward ends 96, 98 of capture plates 76, 90 as aforesaid, pulley block 120
continues rolling rearwardly along cable 4, until pulley block 120
collides with bumper block 50. The latter collision stops rider 7 by
transferring the rider's kinetic energy through bumper block 50 and
braking line 10 to braking device 12. The zipline operator's personnel
then manipulate braking line 10 and haul-up line 27 to brake rider 7 to a
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stop and manoeuver rider 7 onto landing platform 2B as previously
explained.
[0031] Figures 6A, 6B, 7 and 8 respectively depict third, fourth
and fifth embodiments of the invention. In the Figure 6A embodiment,
a pair of spaced-apart plates 130, 132 are rollably supported on opposite
sides of cable 4 by pulleys to form a braking block. The opposed legs
134, 136 of U-shaped bracket 138 are fastened to plates 130, 132
respectively with the bracket's bar 140 projecting forwardly of the
braking block, between legs 134, 136. Hook 142 is pivotally fastened
to and projects rearwardly from pulley block 5. The weight of hook
142 downwardly biases hook 142 about its point of pivotal connection to
pulley block 5. Alternatively, a spring (not shown) may be coupled
between pulley block 5 and hook 142 to downwardly bias hook 142
about its point of pivotal connection to pulley block 5. In operation of
the Figure 6A embodiment, pulley block 5 rolls rearwardly along cable
4 until hook 142's downwardly biased, tapered rearward underside 144
collides with bar 140. The collision force overcomes hook 142's
downward bias, pivoting hook 142 upwardly and allowing pulley block
5 to continue rolling rearwardly until hook 142's catch 146 is carried
rearwardly of bar 140. As soon as hook 142's catch 146 is carried
rearwardly of bar 140, hook 142's downward bias forces catch 146
downwardly between legs 134, 136. Any subsequent forward motion of
pulley block 5 along cable 4 engages catch 146 against bar 140, pre-
venting further forward motion of pulley block 5 and rider 7 along cable
4. Bracket 138 and hook 142 thus form a self closing one-way latch
which, when closed to engage catch 146 against bar 140 as aforesaid,
prevents pulley block 5 from rolling forwardly along cable 4.
[0032] In the Figure 6B embodiment, a pair of spaced-apart plates
130, 132 are rollably supported on opposite sides of cable 4 by pulleys
to form a braking block. Hook 142A is pivotally fastened between
plates 130, 132 forwardly of bumper block SOA, and projects forwardly
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of the braking block. Ring 143 is fastened atop pulley block 5. The
weight of hook 142A downwardly biases hook 142A about its point of
pivotal connection to the braking block. Alternatively, a spring (not
shown) may be coupled between plates 130, 132 and hook 142A to
downwardly bias hook 142A about its point of pivotal connection to the
braking block. In operation of the Figure 6B embodiment, pulley block
5 rolls rearwardly along cable 4 until ring 143 collides with hook
142A's downwardly biased, tapered forward underside 144A. The
collision force overcomes hook 142A's downward bias, pivoting hook
142A upwardly and allowing pulley block 5 to continue rolling rear-
wardly until hook 142A's catch 146A is carried forwardly of ring 143.
As soon as hook 142A's catch 146A is carried forwardly of ring 143,
hook 142A's downward bias forces catch 146A downwardly over ring
143. Any subsequent forward motion of pulley block 5 along cable 4
engages ring 143 against catch 146A, preventing further forward motion
of pulley block 5 and rider 7 along cable 4. Hook 142A and ring 143
thus form a self closing one-way latch which, when closed to engage
catch 146A against ring 143 as aforesaid, prevents pulley block 5 from
rolling forwardly along cable 4.
[0033] In the Figure 7 embodiment, a pair of spaced-apart plates
150, 152 are rollably supported on opposite sides of cable 4 by pulleys
(not shown) to form a braking block. Bumper block 153 is mounted
between plates 150, 152. A semi-conical trap 154 is fastened between
plates 150, 152 with the trap's wide, open forward end projecting
forwardly of the braking block. The lower portion 155 of trap 154 is
left open to allow pulley block 5 to roll through trap 154 as explained
below. A plurality of longitudinal slits 156 are cut in trap 154. Each
slit 156 extends from the trap's narrow, open rearward end toward but
does not intersect the trap's wide, open forward end, thereby segment-
ing trap 154 into a plurality of spring blades 158. A bolt 160 having a
rearwardly tapered semi-conical shape is fastened to and projects
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rearwardly from pulley block 5. In operation of the Figure 7 embodi-
ment, pulley block 5 rolls rearwardly along cable 4 until bolt 160
collides with trap 154. The collision force flexes spring blades 158
radially outwardly, allowing pulley block 5 to continue rolling rear-
s wardly until bolt 160's forward face 162 is carried rearwardly of trap
154's rearward end. As soon as forward face 162 is carried rearwardly
of trap 154's rearward end, spring blades 158 flex radially inwardly
back to their original positions, positioning trap 154's rearward end
against bolt 160's forward face 162, thereby preventing subsequent
forward motion of pulley block 5 and rider 7 along cable 4. Trap 154
and bolt 160 thus form a self closing one-way latch which, when closed
to engage bolt 160's forward face 162 against trap 154's rearward end
as aforesaid, prevents pulley block 5 from rolling forwardly along cable
4.
[0034] In the Figure 8 embodiment, a pair of spaced-apart plates
170, 172 are rollably supported on opposite sides of cable 4 by pulleys
(not shown) to form a braking block. Bumper block 173 is mounted
between plates 170, 172. Rearwardly and inwardly tapered wedges
174, 176 are provided on the inward, forward ends of plates 170, 172
respectively. A V-shaped spring blade 178 is fastened to and projects
rearwardly from pulley block 5. In operation of the Figure 8 embodi-
ment, pulley block 5 rolls rearwardly along cable 4 until spring blade
178 collides with the forward ends of plates 170, 172. The collision
force flexes spring blade 178 inwardly toward cable 4, allowing pulley
block 5 to continue rolling rearwardly until spring blade 178's forward
ends 180, 182 are carried rearwardly of wedges 174, 176. As soon as
forward ends 180, 182 are carried rearwardly of wedges 174, 176
spring blade 178 flexes radially outwardly back to its original position,
positioning forward ends 180, 182 against the rearward ends 184, 186
of wedges 174, 176, thereby preventing subsequent forward motion of
pulley block 5 and rider 7 along cable 4. Wedges 174, 176 and spring
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blade 178 thus form a self closing one-way latch which, when closed to
engage forward ends 180, 182 against rearward ends 184, 186 as
aforesaid, prevents pulley block 5 from rolling forwardly along cable 4.
[0035] As will be apparent to those skilled in the art in the light of
the foregoing disclosure, many alterations and modifications are possi-
ble in the practice of this invention without departing from the scope
thereof. For example, struts 8 and crossbar 26 depicted in Figures 1
and 2 can be omitted. In their place, a separate cable (not shown) can
be extended transversely across and above main cable 4, and one of
pulleys 9 rotatably mounted on the separate cable to receive braking line
10 as aforesaid. Accordingly, the scope of the invention is to be
construed in accordance with the substance defined by the following
claims.
