Apparatus for controlled stabilized descent

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.

FIELD OF THE INVENTION

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

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.

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.

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

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.

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.

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.

DETAILED DESCRIPTION

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.

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.

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

Referring now to the drawings and more particularly toFIGS. 1 and 2, it will be seen that one embodiment is shown of the novel apparatus, designated generally by the reference number10. The apparatus10includes a mobile vehicle comprising a trailer11that is adapted to be towed by truck, tractor or similar prime mover. It is pointed out that while the preferred embodiment of the apparatus10includes 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.

In the depiction shown, the trailer11includes a generally rectangular shaped trailer frame12having elongate longitudinal side frame members13that are rigidly secured to front and rear elongate transverse frame members14. 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 member15, of hollow, rectangular cross-sectional configuration, is rigidly secured to the transverse frame members at approximately their respective mid portions. A longitudinal sub-frame member16is secured to the lower surface of the central frame member and extends throughout the length of the latter. Longitudinally spaced apart transverse ribs17rigidly interconnect the longitudinal sub-frame member16with the longitudinal frame members13. The trailer11has suitable ground engaging wheels18for support of the trailer over the surface of the ground. The ground engaging wheels are provided with fenders19of well-known construction.

The trailer is provided with peripheral railings including the longitudinal side railings20that are rigidly interconnected at their ends to front and rear transverse railings21. The side railings20are also connected to the fenders19, as best seen inFIGS. 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.

The trailer is provided with an elongate hitch bar22at its front end, which is secured to the front end of the central longitudinal frame member15and projects longitudinally therefrom. A socket type coupling23is 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 deck24upon which the various components of the apparatus are supported.

The elongate hitch22which projects from the front end of the trailer frame is provided with a trailer jack25rigidly secured to the hitch bar intermediate the ends thereof. The trailer jack25includes a vertically disposed elongate tube26having a nut27secured to the lower end thereof. An elongate jackscrew28projects through the tube and threadedly engages the nut27. A handle29is rigidly secured to the upper end of the jackscrew28and facilitates adjustment of the trailer jack. The lower end of the jackscrew28is provided with a footplate30, which is pivotally connected to the jackscrew by pivot31. The jackscrew is of well-known construction and provides a means for conveniently leveling the front end of the trailer.

The trailer11is also provided with a pair of substantially identical outriggers32at its rear end, as seen inFIGS. 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 outrigger32is comprised of an L-shaped mounting member33including a horizontal member34and a vertical member35. A vertically disposed double acting hydraulic cylinder36is rigidly secured to the vertical member35. The hydraulic cylinder36is provided with a piston rod37which projects downwardly from the lower end of the cylinder. A ground-engaging footplate38is pivotally secured to the lower end of the piston rod by a pivot39. Each outrigger32is also provided with a U-shaped handle that is rigidly secured to the upper end portion of the vertical member35to facilitate movement of the outrigger.

Each outrigger is moveable from a retracted inoperative position, as illustrated inFIG. 1, to an extended operative position, as depicted in FIG.2. The horizontal mounting member34of each outrigger projects through an opening in a bumper41which is secured to the rear transverse frame member and projects downwardly therefrom. An elongate horizontal, longitudinally extending guide42is secured to the lower portion of the trailer frame and is disposed in communicating relation with the opening through the bumper41. The horizontal mounting arm34slides in the horizontal guide42during movement of the associated outrigger between the retracted inoperative and extended operative positions.

It is pointed out that when the outriggers are moved to the outward operative position, the piston will be actuated to extend the piston rod37downwardly until the footplate38engages the surface of the ground. Conversely, when the outriggers are moved to the inoperative position, the piston rods37will first be retracted and outriggers will then be moved in a forward direction to the retracted inoperative position.

The apparatus10includes a boom assembly43that is pivotally mounted on the trailer11for swinging movement between a vertical operative position and a horizontal inoperative position. The boom assembly43includes an elongate mounting arm44of angular configuration including a lower arm section45and an upper arm section46which is integral with the lower arm section and extends angularly therefrom. The lower end of the elongate mounting arm44is pivotally connected to the upper end of a vertically disposed post47by a pivot48as best seen FIG.1. In this regard, the post47is rigidly affixed to the central longitudinal frame member15at the rear end thereof. The post47is vertically disposed and is provided with a clevis49at its upper end, which accommodates the pivot48. An oblique strut50is rigidly affixed to and extends between the trailer and the vertical post47. In other implementations of the invention the elongate mounting arm can be formed such that it is a single piece.

The boom assembly43also includes an elongate substantially straight hollow mounting boom member51which is optionally of rectangular cross-sectional configuration and which is rigidly secured at one end thereof to the end of the upper arm section46, as best seen in FIG.1. It will be noted that the end of the mounting boom member51to which the upper arm section is affixed is the lower end of the mounting boom member. An elongate substantially oblique brace52is rigidly secured to the mounting arm44at approximately the juncture of the upper and lower arm sections thereof. The other end of the oblique brace52is rigidly secured to the mounting boom member51adjacent the mid portion thereof. It will therefore be seen that the boom assembly43is swingable between an inoperative horizontal position, as illustrated inFIG. 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 member51will be disposed in a vertical or substantially vertical position.

The boom assembly43can be shifted between the operative and inoperative positions by various powered devices, such as a double acting hydraulic cylinder53which has one end thereof secured to a clevis54by pivot55. It will be noted that the clevis54is rigidly secured to the upper surface of the central longitudinal frame member15of the trailer frame12in the implementation shown. The hydraulic cylinder53is provided with a piston having a piston rod56secured thereto and projecting therefrom. The end of the piston rod56is provided with a clevis that is secured by a pivot57to an apertured bracket58. The apertured bracket58is rigidly secured to the lower end portion of the lower arm section45and, in the embodiment shown, a plurality of apertures are formed in the bracket. The openings or apertures in the bracket58allow adjustable attachment of the piston rod to the bracket. It will be seen that when the piston rod56is extended, the boom assembly43will be moved from the inoperative position, as illustrated inFIG. 1, to the operative position illustrated in FIG.2. Conversely, when the piston rod56is retracted, the boom assembly will then be shifted to the horizontal inoperative position, as illustrated in FIG.1.

In the embodiment shown a vertically disposed support post59is provided for supporting the boom assembly43in the inoperative horizontal position as best seen in FIG.1. The support post59is also rigidly secured at its lower end to the central longitudinal frame member15and projects upwardly therefrom. A substantially flat rectangular support plate60is rigidly affixed to the upper end of the support post59and provides a supporting surface for supporting the boom assembly43in the inoperative position. The support post59is also provided with an L-shaped support bracket61rigidly affixed to one side thereof and projecting outwardly therefrom. The function of the L-shaped support bracket61will be more fully described hereinbelow. Finally, it will be noted that support post59has a vertical dimension greater than the vertical dimension of the post47. It will be noted that the mid portion of the mounting boom member51engages and rests on the support post59when the boom assembly43is in the inoperative horizontal position.

The boom assembly43also includes a moveable boom structure62that is telescopically extensible and retractable with respect to the mounting boom member51. 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 member63, a distal boom member64, and a plurality of intermediate boom members65. These boom members telescope within each other and within the mounting boom member51when 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.

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.

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 structure52be comprised of at least two moveable boom members.

Since the moveable booms telescope within each other, the boom members diminish in cross-sectional size beginning with the proximal boom member63and ending with the distal boom member64. The proximal boom member63is of course also smaller in cross-sectional size than the mounting boom member51. The outer ends of each of the moveable boom members can be provided with an out turned annular flange66.

The extensible movement of the moveable boom member relative to each other and relative to the mounting boom member51is normally limited. This limiting can be accomplished by a pair of opposed locking mechanisms67for each of the boom members (normally with the exception of the distal boom member). It will also be noted that the mounting boom member51is also provided with a pair of locking mechanisms67. Each opposed pair of these locking mechanisms is located adjacent the lower end portion of the associated boom member. Each locking mechanism67includes a pair of ears68which are secured to the associated boom member. The ears are apertured and a locking pawl69is secured to the ears by pivot70. Each locking pawl70includes a camming surface71which 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 pawl69also includes a locking surface72that is straight and defines one end of the locking pawl.

The upper end portion of each of the moveable boom members is also provided with a pair of opposed openings73therein, each opening defining a locking edge74. The locking pawl69of each locking mechanism67is urged in a direction against the adjacent moveable boom member by a jack spring75, which is secured to the pivot70of each locking mechanism.

Each locking mechanism67includes an opening76in the associated boom member through which the locking pawl69projects. When the moveable boom members are in the retracted position, the locking pawls69for 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 springs75into the opening73. Each opening76will communicate with an opening73. When this occurs, the locking edge74defined by the opening73will engage the locking surface72of the locking pawl thereby limiting any further extensible movement of the associated boom member. The proximal boom member63will also be limited in its extensible movement by the pair of locking mechanisms67mounted on the mounting boom51.

A support or basket77for a worker is attached to the distal boom member64of the boom assembly. In the embodiment shown inFIG. 3, the support is in the form of an open top cylindrical basket77for accommodating a single worker. The basket77has a bottom wall78and vertical frame elements79secured to the bottom wall and projecting upwardly therefrom. Vertically spaced apart upper, intermediate and lower annular frame elements79aare secured to the vertical frame elements. The upper annular frame element is of sectional construction and defines a gate79bto allow a worker to access the basket77.

An elongate vertically disposed hanger arm80is rigidly secured to the annular frame elements77aof the worker's basket77and extends upwardly therefrom. The hanger arm is substantially straight and includes an intermediate offset portion81extending at right angles thereto. The hanger arm terminates in an upward end portion82, which is disposed at right angles to the intermediate portion81and is substantially parallel to arm80. The upper end portion82projects into the distal end of the distal boom member and is secured thereto by a pin43. It is pointed out that the worker's support77cannot swing or rotate and remains stable during descent, suspension and retrieval to and from the underground work location.

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 cable84which has one end thereof secured to a power driven winch assembly85mounted on the mounting boom member51. The other end of the cable84is secured to the upper end portion of the distal boom member64. In the embodiment shown, the lower end of the cable84is secured to a hook86having a spring urged keeper87. A cross bar88extends transversely across the upper end portion of the lower distal member and is engaged by the hook86to anchor the end of the cable to the distal boom member.

The cable84is trained over a pulley89secured to the upper end of the fixed boom member by a bracket90. In the embodiment shown, the power winch assembly85is secured to a bracket91, which in turn is secured to the mounting boom member51. The power winch assembly85includes a hydraulic motor92secured to the bracket91and having an output shaft shown (not shown) which is drivingly connected to the components of a gear reduction box93.

The output shaft of the gear reduction box is drivingly connected to the winch unit94about which the cable84is wound. The hydraulic motor92is reversible and when it is driven in one direction, the cable84will 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.

In the embodiment depicted, a reversible hydraulic pump95mounted on the deck24of the trailer11drives the reversible hydraulic motor92. A twenty (20) horsepower (HP) Honda engine96also mounted on the trailer deck and whose output shaft is drivingly connected to the hydraulic pump95drives the hydraulic pump95. The output shaft of the 20 HP Honda engine is provided with drive pulleys97having belts98trained thereover, as best seen in FIG.2. The belts98are also trained about driven pulleys99which are mounted on the input shaft of an electric generator100. The generator is mounted on the deck closely adjacent the hydraulic pump and 20 HP Honda engine.

A hydraulic fluid reservoir101is mounted on the deck adjacent the hydraulic pump and the reservoir is part of the hydraulic circuit for the hydraulic pump. An electric storage battery102and a fuel tank103containing fluid for the Honda engine are also mounted on the deck.

Referring again toFIGS. 1 and 2, it will be seen that a substantially flat generally rectangular shaped bracket104is rigidly secured to the mounting boom member51adjacent the lower end portion thereof in the specific example embodiment shown. This mounting bracket has a pair of floodlights105attached 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 bracket104also serves to mount a pair of laterally spaced apart rotating flashing warning lights106. 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.

The apparatus can also be provided with a portable, knockdown barrier or fence structure107that 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 structure107includes a pair of similar longitudinal, fence members108which are releasably connected to a transverse fence member109by suitable latching means110. When the latching means110are unlatched, three fence members are disconnected and may be separately removed. The rear transverse frame member14of the trailer frame12is provided with a pair of laterally spaced apart apertured ears111which receive pins from the longitudinal fence members108. This arrangement allows the barrier structure107to be secured to the rear transverse frame member of the trailer frame12when the boom assembly is in the vertical operative position.

The barrier structure107is disassembled for transport. When in the disassembled condition, the fence members are supported by the bracket61on the post59. In certain instances, the underground work to be performed may require more than one worker. However, the basket77cannot accommodate more than a single worker. Therefore a generally rectangular shaped multiple man support or basket113is provided having a bottom wall114and upright opposed side walls115of open framework construction. The basket113also has a hinged gate116provided with a latch to permit the opening, closing and locking of the gate.

The multiple man support is also provided with a hanger arm117which is substantially identical in construction to the hanger arm80disclosed in the embodiment of FIG.3. The manner in which the multiple man support113is attached to the lower end of the distal moveable boom member is substantially the same as that disclosed in FIG.3.

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 inFIG. 1during 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 cylinders36will be actuated to extend the piston rods to the extended position so that the foot plate38for each outrigger engages the surface of the ground. The double acting hydraulic cylinder53will then be extended to raise the boom assembly43to 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 structure107will be assembled and attached to the rear of the trailer in obstructing relation with the respect to the shaft.

A control device120for operating the winch assembly86, the double acting cylinder53and the outriggers32are located on the trailer and the control device is designated by the reference numeral118. The control device120includes four levers121for manually actuating each of the outriggers, the cylinder53and the winch assembly85. 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 device120also includes four solenoids (not shown) for operating the valves by an operator located in the basket. In this regard, a remote unit119is provided to allow an operator to control the control valves.

When the boom assembly is in the operating position and the apparatus is ready for extension downwardly, a worker will enter the basket77and the control valve for operating the winch assembly will be actuated to unwind the cable84from 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.

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.

It again will be noted that moveable boom assembly and the worker's support77will be maintained in a stable condition during descent, suspension and retrieval. In this regard, attention is directed toFIG. 6, which illustrates the worker's support77, and its relation to the moveable boom assembly62in 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 support77. 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.

If any of the moveable boom members are extended to their full telescopic extension, then the locking mechanism67will 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 cable84to 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 support77to be maintained in a stable condition against side loading or rotative movement.

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.