U.S. patent application number 10/917003 was filed with the patent office on 2005-01-13 for apparatus for controlled stabilized descent.
Invention is credited to Benjamin, David R., Overby, Steven L..
Application Number | 20050006175 10/917003 |
Document ID | / |
Family ID | 26883458 |
Filed Date | 2005-01-13 |
United States Patent
Application |
20050006175 |
Kind Code |
A1 |
Overby, Steven L. ; et
al. |
January 13, 2005 |
Apparatus for controlled stabilized descent
Abstract
An apparatus for descent, suspension and retrieval of a worker
through an opening in the ground includes a trailer having a boom
assembly mounted thereon is described. The boom assembly includes
telescopically extensible and retractable boom members that are
extended downwardly by action of gravity through opening to a
subsurface location. The worker is supported in a stabilized manner
during descent, suspension, and retraction of the boom members.
Inventors: |
Overby, Steven L.; (Miltona,
MN) ; Benjamin, David R.; (Isanti, MN) |
Correspondence
Address: |
Attn: Daniel M. Pauly
MERCHANT & GOULD P.C.
P.O. Box 2903
Minneapolis
MN
55402-0903
US
|
Family ID: |
26883458 |
Appl. No.: |
10/917003 |
Filed: |
August 12, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10917003 |
Aug 12, 2004 |
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09801188 |
Mar 7, 2001 |
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60187845 |
Mar 8, 2000 |
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Current U.S.
Class: |
182/142 |
Current CPC
Class: |
A62B 1/02 20130101; B66F
11/04 20130101 |
Class at
Publication: |
182/142 |
International
Class: |
E04G 021/14 |
Claims
1. An apparatus for the descent and retrieval of a worker through
an opening in a surface leading to a sub-surface location, the
apparatus comprising: a boom assembly having a plurality of
elongate moveable boom members; and a support secured to the boom
assembly for supporting a person to provide stabilized descent,
suspension, and retraction of a person into the sub-surface
location; wherein at least some of the plurality of elongate
moveable boom members are configured to telescope and to enter the
sub-surface location.
2. The apparatus of claim 1, wherein at least some of the plurality
of elongate moveable boom members are configured to telescope by
sliding into the interior of other moveable boom members.
3. The apparatus of claim 1, wherein the boom assembly is pivotable
with respect to the surface.
4. The apparatus of claim 1, wherein the boom assembly can rotate
within at least one direction.
5. The apparatus of claim 4, wherein the boom assembly can rotate
within at least two directions.
6. The apparatus of claim 1, further comprising means for limiting
extensible movement of each boom member.
7. The apparatus of claim 1, further comprising a power means for
raising and lowering the support.
8. The apparatus of claim 1, further comprising a mobile transport
device.
9. The apparatus of claim 1, wherein the boom assembly is disposed
in a substantially horizontally position when in an inoperative
position.
10. The apparatus of claim 1, wherein the boom assembly is disposed
in a substantially vertical position when in an operative
position.
11. The apparatus of claim 1, wherein the boom assembly may be
shifted between various operative positions.
12. The apparatus of claim 1, further comprising a remote control
for controlling operation of the apparatus from underground.
13. The apparatus of claim 1, further comprising a device for
forming a barrier around an opening through which the boom assembly
can be extended and retracted.
14. An apparatus for the descent and retrieval of a worker through
an opening in a surface leading to a sub-surface location, the
apparatus comprising: a boom assembly having a plurality of
elongate moveable boom members, wherein at least some of the
elongate boom members can telescope by sliding into the interior of
other moveable boom members; and a support secured to the boom
assembly for supporting a person to provide stabilized descent,
suspension, and retraction of a person into the sub-surface
location.
15. The apparatus of claim 14, wherein the boom assembly is
pivotable with respect to the surface.
16-20. (Cancelled)
Description
FIELD OF THE INVENTION
[0001] This invention relates to an apparatus for use in the
stabilized descent, suspension, and retrieval of a worker and
equipment through an opening to an underground location.
BACKGROUND OF THE INVENTION
[0002] In the course of accomplishing various construction,
maintenance, and supervision tasks, people must often work
underground, such as when working in a underground sewer or
communications enclosure. These people are required to move
vertically downwardly through a confined space entry to a below
surface location where the work is to be performed. In other
instances, rescue personnel descend through a confined space entry
when making a rescue of a person located at some underground
location. In many instances, there are no support structures, such
as ladders, for supporting a person engaged in underground work or
rescue efforts.
[0003] Devices have been developed for supporting workers or
rescuers descending through a confined space entry to an
underground location. For example, Elvin Safety Supply, Inc.
markets systems having tripod and davit arm for descent and
retrieval of workers through a confined space entry. In the Elvin
system a worker is suspended by a cable from the tripod or davit
arm device. The use of a suspension cable in this type of descent
and retrieval system allows the worker to swing uncontrollably
within the underground space, which renders this system unstable
for the worker and inadequate for many purposes. Other types of
prior art devices embody very large expensive and cumbersome
systems used essentially by urban sewer districts for underground
work. These large systems also suspend the worker support by
cables.
[0004] The primary problem with these prior art systems is their
incapability of providing stabilized descent, suspension, and
retrieval of a worker or rescuer. Therefore, a need exists for a
device permitting descent of a worker into an underground space or
confined space that provides controlled and stabilized descent,
suspension, and retrieval.
SUMMARY OF THE INVENTION
[0005] An object of this invention to provide a novel apparatus for
use in providing stabilized descent and retrieval of a worker or
rescuer through a surface entry to and from an underground
location.
[0006] A more specific object of this invention is to provide an
apparatus for the stabilized descent, suspension and retrieval of a
worker supported on a support connected to extensible and
retractable elongate boom members which are extended downwardly by
action of gravity through an opening to an underground location and
which are retracted by power means for retrieving the worker
support.
[0007] The apparatus includes a boom assembly mounted on a vehicle
and including extensible and retractable telescopic boom members.
The boom assembly is shiftable between operative and inoperative
positions. The boom assembly is generally vertically oriented in an
operative position and is provided with a worker's support basket
that descends through an opening in the surface to an underground
location. A power driven winch serves to retract the boom members
to a retracted position from an extended position. The power driven
winch also retains the boom assembly in the retracted position but
permits the boom assembly to descend downwardly by action of
gravity.
BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWINGS
[0008] FIG. 1 is a side elevational view of a device for lowering a
person into a subterranean space, illustrating the boom assembly in
a retracted inoperative position;
[0009] FIG. 2 is a side elevational view of the device for lowering
a person into a subterranean space and with the boom assembly in an
extended condition;
[0010] FIG. 3 is a top plan view thereof;
[0011] FIG. 4 is a fragmentary side elevational view of the device
for lowering a person into a subterranean space with the boom
assembly in the extended position;
[0012] FIG. 5 is a cross-sectional view taken approximately along
line 5-5 of FIG. 1 and looking in the direction of the arrows.
DETAILED DESCRIPTION
[0013] The present invention is directed to an apparatus for the
descent and retrieval of a worker through an opening in a surface
leading to a sub-surface location. The apparatus comprises a boom
assembly having a plurality of elongate moveable boom members; and
a support secured to the boom assembly for supporting a person to
provide stabilized descent, suspension, and retraction of the
person into a sub-surface location.
[0014] In certain embodiments the apparatus is configured such that
at least some of the plurality of elongate moveable boom members
are configured to telescope by sliding into the interior of other
moveable boom members. In this manner the boom provide a compact
but stable apparatus for entry into subsurface space. The
telescoping form of the boom members allows the support to travel
through a relatively small opening. Also, the boom members are
optionally pivotable with respect to the surface and can be
configured to rotate within at least one direction. The boom
assembly is configured to rotate within at least two directions in
some implementations, and may include means for limiting extensible
movement of each boom member. This ability to pivot or rotate
allows the support to be centered over the opening without
relocating the entire apparatus, and also allows the support to be
repositioned horizontally when underground.
[0015] A remote control can be used for controlling operation of
the apparatus from underground. Specific embodiments also include a
power means for raising and lowering the support. Normally the
apparatus is secured to a mobile transport device, such as a
trailer or the bed of a vehicle. In an example implementation the
boom assembly can be contracted and disposed in a substantially
horizontally position when not in use, and then raised into a
vertical position when in an operative position when used
[0016] Referring now to the drawings and more particularly to FIGS.
1 and 2, it will be seen that one embodiment is shown of the novel
apparatus, designated generally by the reference number 10. The
apparatus 10 includes a mobile vehicle comprising a trailer 11 that
is adapted to be towed by truck, tractor or similar prime mover. It
is pointed out that while the preferred embodiment of the apparatus
10 includes a trailer, other kinds of transport vehicles such as
pick-up trucks or similar type vehicles may be used. Thus, the
device can be mounted on a trailer or an be mounted directly to a
powered vehicle, such as mounting within the bed of a truck.
[0017] In the depiction shown, the trailer 11 includes a generally
rectangular shaped trailer frame 12 having elongate longitudinal
side frame members 13 that are rigidly secured to front and rear
elongate transverse frame members 14. The transverse frame members
define the front and rear of the trailer. The transverse frame
members and the longitudinal side are of hollow, rectangular
shaped, cross-sectional configuration in the embodiment shown. A
central elongate longitudinal frame member 15, of hollow,
rectangular cross-sectional configuration, is rigidly secured to
the transverse frame members at approximately their respective mid
portions. A longitudinal sub-frame member 16 is secured to the
lower surface of the central frame member and extends throughout
the length of the latter. Longitudinally spaced apart transverse
ribs 17 rigidly interconnect the longitudinal sub-frame member 16
with the longitudinal frame members 13. The trailer 11 has suitable
ground engaging wheels 18 for support of the trailer over the
surface of the ground. The ground engaging wheels are provided with
fenders 19 of well-known construction.
[0018] The trailer is provided with peripheral railings including
the longitudinal side railings 20 that are rigidly interconnected
at their ends to front and rear transverse railings 21. The side
railings 20 are also connected to the fenders 19, as best seen in
FIGS. 1 and 2. It will therefore be seen that the railings extend
around the entire periphery of the trailer and prevent any
components supported on the trailer from accidentally sliding from
the trailer.
[0019] The trailer is provided with an elongate hitch bar 22 at its
front end, which is secured to the front end of the central
longitudinal frame member 15 and projects longitudinally therefrom.
A socket type coupling 23 is secured to the front end of the
elongate hitch bar and is part of a ball and socket coupling of
well-known construction. The trailer is also provided with a flat
deck 24 upon which the various components of the apparatus are
supported.
[0020] The elongate hitch 22 which projects from the front end of
the trailer frame is provided with a trailer jack 25 rigidly
secured to the hitch bar intermediate the ends thereof. The trailer
jack 25 includes a vertically disposed elongate tube 26 having a
nut 27 secured to the lower end thereof. An elongate jackscrew 28
projects through the tube and threadedly engages the nut 27. A
handle 29 is rigidly secured to the upper end of the jackscrew 28
and facilitates adjustment of the trailer jack. The lower end of
the jackscrew 28 is provided with a footplate 30, which is
pivotally connected to the jackscrew by pivot 31. The jackscrew is
of well-known construction and provides a means for conveniently
leveling the front end of the trailer.
[0021] The trailer 11 is also provided with a pair of substantially
identical outriggers 32 at its rear end, as seen in FIGS. 1 and 2.
The outriggers serve to support and stabilize the rear end of the
apparatus when the apparatus is in an operative position. Each
outrigger 32 is comprised of an L-shaped mounting member 33
including a horizontal member 34 and a vertical member 35. A
vertically disposed double acting hydraulic cylinder 36 is rigidly
secured to the vertical member 35. The hydraulic cylinder 36 is
provided with a piston rod 37 which projects downwardly from the
lower end of the cylinder. A ground-engaging footplate 38 is
pivotally secured to the lower end of the piston rod by a pivot 39.
Each outrigger 32 is also provided with a U-shaped handle that is
rigidly secured to the upper end portion of the vertical member 35
to facilitate movement of the outrigger.
[0022] Each outrigger is moveable from a retracted inoperative
position, as illustrated in FIG. 1, to an extended operative
position, as depicted in FIG. 2. The horizontal mounting member 34
of each outrigger projects through an opening in a bumper 41 which
is secured to the rear transverse frame member and projects
downwardly therefrom. An elongate horizontal, longitudinally
extending guide 42 is secured to the lower portion of the trailer
frame and is disposed in communicating relation with the opening
through the bumper 41. The horizontal mounting arm 34 slides in the
horizontal guide 42 during movement of the associated outrigger
between the retracted inoperative and extended operative
positions.
[0023] It is pointed out that when the outriggers are moved to the
outward operative position, the piston will be actuated to extend
the piston rod 37 downwardly until the footplate 38 engages the
surface of the ground. Conversely, when the outriggers are moved to
the inoperative position, the piston rods 37 will first be
retracted and outriggers will then be moved in a forward direction
to the retracted inoperative position.
[0024] The apparatus 10 includes a boom assembly 43 that is
pivotally mounted on the trailer 11 for swinging movement between a
vertical operative position and a horizontal inoperative position.
The boom assembly 43 includes an elongate mounting arm 44 of
angular configuration including a lower arm section 45 and an upper
arm section 46 which is integral with the lower arm section and
extends angularly therefrom. The lower end of the elongate mounting
arm 44 is pivotally connected to the upper end of a vertically
disposed post 47 by a pivot 48 as best seen FIG. 1. In this regard,
the post 47 is rigidly affixed to the central longitudinal frame
member 15 at the rear end thereof. The post 47 is vertically
disposed and is provided with a clevis 49 at its upper end, which
accommodates the pivot 48. An oblique strut 50 is rigidly affixed
to and extends between the trailer and the vertical post 47. In
other implementations of the invention the elongate mounting arm
can be formed such that it is a single piece.
[0025] The boom assembly 43 also includes an elongate substantially
straight hollow mounting boom member 51 which is optionally of
rectangular cross-sectional configuration and which is rigidly
secured at one end thereof to the end of the upper arm section 46,
as best seen in FIG. 1. It will be noted that the end of the
mounting boom member 51 to which the upper arm section is affixed
is the lower end of the mounting boom member. An elongate
substantially oblique brace 52 is rigidly secured to the mounting
arm 44 at approximately the juncture of the upper and lower arm
sections thereof. The other end of the oblique brace 52 is rigidly
secured to the mounting boom member 51 adjacent the mid portion
thereof. It will therefore be seen that the boom assembly 43 is
swingable between an inoperative horizontal position, as
illustrated in FIG. 1, about a horizontal transverse axis and a
vertical operative position, as illustrated in FIG. 2. When the
boom assembly is in the operative position, the mounting boom
member 51 will be disposed in a vertical or substantially vertical
position.
[0026] The boom assembly 43 can be shifted between the operative
and inoperative positions by various powered devices, such as a
double acting hydraulic cylinder 53 which has one end thereof
secured to a clevis 54 by pivot 55. It will be noted that the
clevis 54 is rigidly secured to the upper surface of the central
longitudinal frame member 15 of the trailer frame 12 in the
implementation shown. The hydraulic cylinder 53 is provided with a
piston having a piston rod 56 secured thereto and projecting
therefrom. The end of the piston rod 56 is provided with a clevis
that is secured by a pivot 57 to an apertured bracket 58. The
apertured bracket 58 is rigidly secured to the lower end portion of
the lower arm section 45 and, in the embodiment shown, a plurality
of apertures are formed in the bracket. The openings or apertures
in the bracket 58 allow adjustable attachment of the piston rod to
the bracket. It will be seen that when the piston rod 56 is
extended, the boom assembly 43 will be moved from the inoperative
position, as illustrated in FIG. 1, to the operative position
illustrated in FIG. 2. Conversely, when the piston rod 56 is
retracted, the boom assembly will then be shifted to the horizontal
inoperative position, as illustrated in FIG. 1.
[0027] In the embodiment shown a vertically disposed support post
59 is provided for supporting the boom assembly 43 in the
inoperative horizontal position as best seen in FIG. 1. The support
post 59 is also rigidly secured at its lower end to the central
longitudinal frame member 15 and projects upwardly therefrom. A
substantially flat rectangular support plate 60 is rigidly affixed
to the upper end of the support post 59 and provides a supporting
surface for supporting the boom assembly 43 in the inoperative
position. The support post 59 is also provided with an L-shaped
support bracket 61 rigidly affixed to one side thereof and
projecting outwardly therefrom. The function of the L-shaped
support bracket 61 will be more fully described hereinbelow.
Finally, it will be noted that support post 59 has a vertical
dimension greater than the vertical dimension of the post 47. It
will be noted that the mid portion of the mounting boom member 51
engages and rests on the support post 59 when the boom assembly 43
is in the inoperative horizontal position.
[0028] The boom assembly 43 also includes a moveable boom structure
62 that is telescopically extensible and retractable with respect
to the mounting boom member 51. The moveable boom structure is
comprised of a plurality of substantially straight hollow moveable
boom members. In the implementation shown, the boom members have
rectangular cross-sectional configuration, and include a proximal
boom member 63, a distal boom member 64, and a plurality of
intermediate boom members 65. These boom members telescope within
each other and within the mounting boom member 51 when in a fully
retracted position and are extended telescopically to their full
extension when in a fully extended position. However, it is pointed
out that the moveable boom members can be variously adjusted
between the fully retracted and the fully extended positions.
[0029] In a specific embodiment, each of the moveable boom members
is approximately ten feet long and six such boom members are
preferably used in the moveable boom structure to permit the boom
members to be extended to a depth of approximately slightly less
than sixty feet.
[0030] However, it is pointed out that the moveable boom structure
may be comprised of boom members of different lengths and
configurations, and different numbers of boom members may also be
used. For example, although the preferred embodiment utilizes six
boom members in order to obtain a depth of approximately sixty
feet, fewer boom members of greater length could also be used to
achieve a similar or different depth. However, it is pointed out
that it is preferred that moveable boom structure 52 be comprised
of at least two moveable boom members.
[0031] Since the moveable booms telescope within each other, the
boom members diminish in cross-sectional size beginning with the
proximal boom member 63 and ending with the distal boom member 64.
The proximal boom member 63 is of course also smaller in
cross-sectional size than the mounting boom member 51. The outer
ends of each of the moveable boom members can be provided with an
out turned annular flange 66.
[0032] The extensible movement of the moveable boom member relative
to each other and relative to the mounting boom member 51 is
normally limited. This limiting can be accomplished by a pair of
opposed locking mechanisms 67 for each of the boom members
(normally with the exception of the distal boom member). It will
also be noted that the mounting boom member 51 is also provided
with a pair of locking mechanisms 67. Each opposed pair of these
locking mechanisms is located adjacent the lower end portion of the
associated boom member. Each locking mechanism 67 includes a pair
of ears 68 which are secured to the associated boom member. The
ears are apertured and a locking pawl 69 is secured to the ears by
pivot 70. Each locking pawl 70 includes a camming surface 71 which
is somewhat curved and is positioned to slide along the external
surface of the adjacent moveable boom member as the boom member is
moved. Each pawl 69 also includes a locking surface 72 that is
straight and defines one end of the locking pawl.
[0033] The upper end portion of each of the moveable boom members
is also provided with a pair of opposed openings 73 therein, each
opening defining a locking edge 74. The locking pawl 69 of each
locking mechanism 67 is urged in a direction against the adjacent
moveable boom member by a jack spring 75, which is secured to the
pivot 70 of each locking mechanism.
[0034] Each locking mechanism 67 includes an opening 76 in the
associated boom member through which the locking pawl 69 projects.
When the moveable boom members are in the retracted position, the
locking pawls 69 for each pair of locking mechanisms will be urged
outwardly into an unlocked condition. When the moveable boom
members are extended, the locking pawl will be cammed outwardly by
the moving adjacent boom member until the locking pawls are urged
by the jack springs 75 into the opening 73. Each opening 76 will
communicate with an opening 73. When this occurs, the locking edge
74 defined by the opening 73 will engage the locking surface 72 of
the locking pawl thereby limiting any further extensible movement
of the associated boom member. The proximal boom member 63 will
also be limited in its extensible movement by the pair of locking
mechanisms 67 mounted on the mounting boom 51.
[0035] A support or basket 77 for a worker is attached to the
distal boom member 64 of the boom assembly. In the embodiment shown
in FIG. 3, the support is in the form of an open top cylindrical
basket 77 for accommodating a single worker. The basket 77 has a
bottom wall 78 and vertical frame elements 79 secured to the bottom
wall and projecting upwardly therefrom. Vertically spaced apart
upper, intermediate and lower annular frame elements 79a are
secured to the vertical frame elements. The upper annular frame
element is of sectional construction and defines a gate 79b to
allow a worker to access the basket 77.
[0036] An elongate vertically disposed hanger arm 80 is rigidly
secured to the annular frame elements 77a of the worker's basket 77
and extends upwardly therefrom. The hanger arm is substantially
straight and includes an intermediate offset portion 81 extending
at right angles thereto. The hanger arm terminates in an upward end
portion 82, which is disposed at right angles to the intermediate
portion 81 and is substantially parallel to arm 80. The upper end
portion 82 projects into the distal end of the distal boom member
and is secured thereto by a pin 43. It is pointed out that the
worker's support 77 cannot swing or rotate and remains stable
during descent, suspension and retrieval to and from the
underground work location.
[0037] Means are provided for retracting the moveable boom
structure from the extended position and for controlling downward
extension of the boom section to an extended position. This means
includes an elongate flexible cable 84 which has one end thereof
secured to a power driven winch assembly 85 mounted on the mounting
boom member 51. The other end of the cable 84 is secured to the
upper end portion of the distal boom member 64. In the embodiment
shown, the lower end of the cable 84 is secured to a hook 86 having
a spring urged keeper 87. A cross bar 88 extends transversely
across the upper end portion of the lower distal member and is
engaged by the hook 86 to anchor the end of the cable to the distal
boom member.
[0038] The cable 84 is trained over a pulley 89 secured to the
upper end of the fixed boom member by a bracket 90. In the
embodiment shown, the power winch assembly 85 is secured to a
bracket 91, which in turn is secured to the mounting boom member
51. The power winch assembly 85 includes a hydraulic motor 92
secured to the bracket 91 and having an output shaft shown (not
shown) which is drivingly connected to the components of a gear
reduction box 93.
[0039] The output shaft of the gear reduction box is drivingly
connected to the winch unit 94 about which the cable 84 is wound.
The hydraulic motor 92 is reversible and when it is driven in one
direction, the cable 84 will retract the moveable boom members from
an extended position in a retracting direction. When the hydraulic
motor is driven in the opposite direction, the cable will be
unwound from the winch as the boom members are extended. Downward
extension of the moveable boom members is by action of gravity.
[0040] In the embodiment depicted, a reversible hydraulic pump 95
mounted on the deck 24 of the trailer 11 drives the reversible
hydraulic motor 92. A twenty (20) horsepower (HP) Honda engine 96
also mounted on the trailer deck and whose output shaft is
drivingly connected to the hydraulic pump 95 drives the hydraulic
pump 95. The output shaft of the 20 HP Honda engine is provided
with drive pulleys 97 having belts 98 trained thereover, as best
seen in FIG. 2. The belts 98 are also trained about driven pulleys
99 which are mounted on the input shaft of an electric generator
100. The generator is mounted on the deck closely adjacent the
hydraulic pump and 20 HP Honda engine.
[0041] A hydraulic fluid reservoir 101 is mounted on the deck
adjacent the hydraulic pump and the reservoir is part of the
hydraulic circuit for the hydraulic pump. An electric storage
battery 102 and a fuel tank 103 containing fluid for the Honda
engine are also mounted on the deck.
[0042] Referring again to FIGS. 1 and 2, it will be seen that a
substantially flat generally rectangular shaped bracket 104 is
rigidly secured to the mounting boom member 51 adjacent the lower
end portion thereof in the specific example embodiment shown. This
mounting bracket has a pair of floodlights 105 attached thereto and
the floodlights face in a rear direction when the boom assembly is
an inoperative horizontal position, but face downwardly when the
boom assembly is in the operative erect position. The bracket 104
also serves to mount a pair of laterally spaced apart rotating
flashing warning lights 106. When the boom assembly is in the
vertical operative position, the warning lights will be disposed
above the opening in the ground surface and will be at a level to
be readily seen by a person in that vicinity. The floodlights and
warning lights are connected by suitable conductors (not shown) to
the generator battery electrical system.
[0043] The apparatus can also be provided with a portable,
knockdown barrier or fence structure 107 that is rigidly positioned
around the entry opening in the surface of the ground to prevent a
pedestrian from inadvertently falling into the opening. The barrier
or fence structure 107 includes a pair of similar longitudinal,
fence members 108 which are releasably connected to a transverse
fence member 109 by suitable latching means 110. When the latching
means 110 are unlatched, three fence members are disconnected and
may be separately removed. The rear transverse frame member 14 of
the trailer frame 12 is provided with a pair of laterally spaced
apart apertured ears 111 which receive pins from the longitudinal
fence members 108. This arrangement allows the barrier structure
107 to be secured to the rear transverse frame member of the
trailer frame 12 when the boom assembly is in the vertical
operative position.
[0044] The barrier structure 107 is disassembled for transport.
When in the disassembled condition, the fence members are supported
by the bracket 61 on the post 59. In certain instances, the
underground work to be performed may require more than one worker.
However, the basket 77 cannot accommodate more than a single
worker. Therefore a generally rectangular shaped multiple man
support or basket 113 is provided having a bottom wall 114 and
upright opposed side walls 115 of open framework construction. The
basket 113 also has a hinged gate 116 provided with a latch to
permit the opening, closing and locking of the gate.
[0045] The multiple man support is also provided with a hanger arm
117 which is substantially identical in construction to the hanger
arm 80 disclosed in the embodiment of FIG. 3. The manner in which
the multiple man support 113 is attached to the lower end of the
distal moveable boom member is substantially the same as that
disclosed in FIG. 3.
[0046] When the apparatus is used to make a repair at an
underground location, the apparatus trailer will be attached to a
towing vehicle and moved to the desired location. The boom assembly
will be in the horizontal inoperative position as illustrated in
FIG. 1 during travel to the location. When the apparatus arrives at
the desired location, the trailer will be positioned adjacent the
opening or vertical shaft o where the work is to be performed. The
outriggers will be angularly pulled outwardly to the extended
operative position and the hydraulic cylinders 36 will be actuated
to extend the piston rods to the extended position so that the foot
plate 38 for each outrigger engages the surface of the ground. The
double acting hydraulic cylinder 53 will then be extended to raise
the boom assembly 43 to the erect operative position so that the
mounting boom and moveable boom structure is positioned directly
over the center of the vertical shaft. The barrier structure 107
will be assembled and attached to the rear of the trailer in
obstructing relation with the respect to the shaft.
[0047] A control device 120 for operating the winch assembly 86,
the double acting cylinder 53 and the outriggers 32 are located on
the trailer and the control device is designated by the reference
numeral 118. The control device 120 includes four levers 121 for
manually actuating each of the outriggers, the cylinder 53 and the
winch assembly 85. Control valves (not shown) are operated by the
levers. The control valves may be conventional spool valves with an
"off" position and reversible "on" positions. The control device
120 also includes four solenoids (not shown) for operating the
valves by an operator located in the basket. In this regard, a
remote unit 119 is provided to allow an operator to control the
control valves.
[0048] When the boom assembly is in the operating position and the
apparatus is ready for extension downwardly, a worker will enter
the basket 77 and the control valve for operating the winch
assembly will be actuated to unwind the cable 84 from the winch.
The flood lights will be energized to illuminate the interior of
the shaft. As the cable unwinds, the moveable boom sections will
extend downwardly by action of gravity. The descent will be
controlled at the rate of unwinding of the cable. Thus the angular
velocity of the winch determines the descent rate.
[0049] The moveable boom structure will be extended until the
operator reaches the desired location. As pointed out above, the
control valves for operating the moveable boom structure may be
controlled by the operator in the worker's support or may be
controlled by an operator located t the surface. In any event, the
worker will reach the desired location and then perform the
necessary work.
[0050] It again will be noted that moveable boom assembly and the
worker's support 77 will be maintained in a stable condition during
descent, suspension and retrieval. In this regard, attention is
directed to FIG. 6, which illustrates the worker's support 77, and
its relation to the moveable boom assembly 62 in one example
implementation of the invention. The longitudinal axis or center
line of the moveable boom assembly is co-extensive with the
longitudinal center line of the support 77. Therefore as the boom
is extended, there will be no side loading of the worker's support
or the moveable boom members as the boom members are telescopically
extended.
[0051] If any of the moveable boom members are extended to their
full telescopic extension, then the locking mechanism 67 will limit
any further movement of the associated boom member in an extensible
direction. After the work has been completed or it is otherwise
desirable to retract the boom assembly, the controls may be
actuated to cause the cable 84 to be wound about the winch of the
winch assembly to the fully retracted position or to a different
location. Again it will be noted that the retractive movement of
the moveable boom structure permits the worker's support 77 to be
maintained in a stable condition against side loading or rotative
movement.
[0052] Thus it will be seen that I have provided a novel apparatus
for providing stabilized descent, suspension and retrieval of a
worker's support, which permits a stabilized platform for allowing
a worker to perform work at an underground location.
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