WO2006073462A2

WO2006073462A2 - Powered personnel ascender

Info

Publication number: WO2006073462A2
Application number: PCT/US2005/015954
Authority: WO
Inventors: Michael D. Jacobson; Tim Walter
Original assignee: Quoin International, Inc.
Priority date: 2005-01-06
Filing date: 2005-05-06
Publication date: 2006-07-13
Also published as: WO2006073462A3

Abstract

A powered rope ascender (10) that supports a person or a load while ascending a vertical roper (112). The rope ascender has a motor (104) driven capstan drum (58) that engages the rope (112). A tension roller (50) reacts with the tensioned rope (112) to force a pinch roller (52) to grip the rope (112) against the capstan drum (58). A load limiting assembly (66) releases the grip by the pinch roller (52) when the load supported by the ascender exceeds a predetermined amount. A centrifugal clutch (210) reduces starting torque required by the motor and the outer drum of the centrifugal clutch interacts with a brake to hold position on the rope (112). Hand controls (88) provide a freewheeling, a braking and an ascending mode of operation. A harmonic drive (60) provides speed reduction from the motor (104) to the capstan drum (58). The powered rope ascender (10) can be threaded on the rope (112) without access to the rope end.

Description

POWERED PERSONNEL ASCENDER

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from U.S. provisional application serial number 60/656,605 filed on February 25, 2005, incorporated herein by reference in its entirety, and from U.S. provisional application serial number 60/642,270 filed on January 6, 2005, incorporated herein by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

OR DEVELOPMENT

[0002] This invention was made with Government support under Grant No.

DAAH 01-03-C-R 164, awarded by the Defense Advanced Research Program Agency (DARPA) and Grant No. FA 8651-04-C-0334, awarded by DARPA. The Government has certain rights in this invention.

INCORPORATION-BY-REFERENCE OF MATERIAL

SUBMITTED ON A COMPACT DISC [0003] Not Applicable

NOTICE OF MATERIAL SUBJECT TO COPYRIGHT PROTECTION [0004] A portion of the material in this patent document is subject to copyright protection under the copyright laws of the United States and of other countries. The owner of the copyright rights has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the United States Patent and Trademark Office publicly available file or records, but otherwise reserves all copyright rights whatsoever. The copyright owner does not hereby waive any of its rights to have this patent document maintained in secrecy, including without limitation its rights pursuant to 37 C.F.R. § 1.14. BACKGROUND OF THE INVENTION 1. Field of the Invention [0005] This invention pertains generally to rope climbing devices, and more particularly to powered rope climbing devices. 2. Description of Related Art

[0006] Climbing devices are used to enable a person to ascend or descend a rope or cable. There are many examples where a climbing device is needed that can be operated by the person ascending the rope, such as mountain climbing, caving, tree trimming, rescue operations and military operations. Industrial uses of a climbing device may include scaling tall structures, towers, poles, mine shafts or bridge works for servicing, cleaning, window washing, painting, etc. [0007] Manual lifting devices, also known as ascenders, are configured to grip a vertical tensioned rope when load is present and to slide when the load is released. Typically, an individual must be capable of repetitively lifting their own weight on the manual ascender when climbing with these devices. [0008] Powered personal lifting devices assist personnel in scaling vertical surfaces. Motorized winches are used to raise or lower personnel on platforms or harnesses attached to ropes. A winch must be anchored to a solid platform above the load or use pulleys coupled to the platform to hoist the load. Further, a winch winds the rope or cable on a spool which limits the length and weight of rope that can be used. Hoists, usually with compound pulleys or reducing gears are used to raise or lower individuals or platforms and must be suspended from a secure support point such as a tripod, beam or bridge crane. Typically a winch or hoist requires at least a second person to operate or control the device in order for a first person to safely ascend a rope. [0009] Portable, climber operated winches are limited by bulky power delivery systems and associated weight of the spool. [0010] Safety is a paramount concern when a person is ascending a rope.

Failure of a component that results in a rapid descent or fall will result in injury or death. Existing ascenders typically have cams, jam cleats or other braking devices that will engage if a sudden or rapid descent is detected. These devices can cause a sudden stop with resulting injury or equipment damage. A lightweight powered ascender with means to brake during ascent, to hold a position on a rope and to descend in a controlled manner is needed. BRIEF SUMMARY OF THE INVENTION

[0011] A powered rope ascender capable of supporting an operator has a motor driven capstan drum to engage the rope. A tension roller forces a pinch roller to grip the rope on the capstan. A centrifugal clutch reduces the starting torque of the motor and services as a brake drum for an integrated brake. A harmonic drive is used to reduce the rpm's of the capstan relative to the motor. A spring loaded load limiting assembly reduces the grip force by the pinch roller when the load supported by the ascender exceeds a predetermined amount and provides for rope slippage during dynamic loading from starting and stopping ascent and descent. The powered rope ascender can be threaded on a rope without access to a rope end.

[0012] In context of this invention, a wrap of rope is defined as either a closed loop of rope on the capstan drum or an open loop of rope contacting the capstan drum and contacting another roller such as a tension roller, pinch roller and/or an idler roller. [0013] An embodiment of the invention is an apparatus for maneuvering on a rope while supporting a load that comprises a base plate, means for engaging the rope coupled to the base plate, where the engaging means is configured to grip the rope, a motor coupled to base plate, where the motor is adapted to propel the engaging means relative to the rope, means for limiting the load coupled to the base plate, where the limiting means is adapted to couple to the load, and where the limiting means is configured to reduce the grip on the rope by the engaging means when the load supported exceeds a predetermined amount. [0014] An aspect of the invention is a motor selected from the group consisting of a DC motor, an AC motor, a brushless motor, a compressed gas turbine, and an internal combustion engine. [0015] Another aspect of the invention is where the motor is coupled to the base plate through a cable drive, and where the motor propels the engaging means through the cable drive. [0016] A further aspect of the invention is where the means for engaging the rope comprises, a capstan drum coupled to the motor, a tension roller bracket having distal and proximal ends and a pivot point between the distal, proximal ends, the tension roller bracket coupled to the base plate at the pivot point, a tension roller coupled to the distal end of the tension roller bracket, a pinch roller coupled to the proximal end of the tension roller bracket, where the pinch roller is positioned to contact the capstan drum, where the rope has an upper region and a lower region relative to the position of the capstan drum, where at least one wrap of rope between the upper region and the lower region of rope is positioned on the capstan drum, where the tension roller is positioned to contact the upper region of the rope, and where the pinch roller is configured to apply a gripping force against the at least one wrap of rope on the capstan drum when a load is supported by the load limiting means.

[0017] A still further aspect of the invention is where the means for engaging the rope further comprises a channel guide coupled to the base plate and adapted to guide the upper region of rope to contact the capstan drum. [0018] Another aspect of the invention is where the means for engaging the rope further comprises an idler roller coupled to the base plate, where the idler roller is positioned adjacent to the capstan drum, and the capstan drum and the idler roller having a plurality of grooves, where the plurality of grooves are adapted to guide the at least one wrap of rope around the idler roller and the capstan drum. [0019] A further aspect of the invention is harmonic drive coupled between the capstan drum and the motor, where the harmonic drive is adapted to reduce the rotation speed of the capstan drum relative to the rotation speed of the motor. [0020] A still further aspect of the invention is a brake coupled to the base plate, a brake drum coupled between the harmonic drive and the motor, where the brake drum has an outer drum surface, and where the brake is adapted to engage the outer drum surface. [0021] Another aspect of the invention is a centrifugal clutch mounted in the brake drum, where the centrifugal clutch is coupled to the motor, and where the centrifugal clutch is adapted to reduce the starting torque required by the motor. [0022] A further aspect of the invention is a control trigger coupled to the base plate, the trigger linked to the brake, the trigger having first, and second positions, a motor control switch linked to the trigger, the motor control switch adapted to energize the motor, where when the trigger is in the first position, the brake is engaged with the outer drum surface and the motor is not energized by the motor control switch, and where when the trigger is in the second position, the brake is disengaged from the outer drum surface and the motor is energized by the motor control switch.

[0023] A still further aspect of the invention is a palm interlock coupled to the base plate, the palm interlock adapted to react to palm pressure by an operator, where the palm interlock is adapted to lock the trigger in the first position when no palm pressure is applied by the operator, and where the palm interlock is adapted to allow the trigger to move to the second position when palm pressure is applied to the palm interlock by the operator. [0024] Another aspect of the invention is the trigger having a third position, where when the trigger is in the third position, the brake is disengaged from the outer clutch drum surface and the motor is not energized by the motor control switch, a palm interlock coupled to the base plate, the palm interlock adapted to react to palm pressure by an operator, where the palm interlock is adapted to lock the trigger in the third position when no palm pressure is applied by the operator, and where the palm interlock is adapted to allow the trigger to move from the third position to the first and the second positions when palm pressure is applied to the palm interlock by the operator. [0025] A further aspect of the invention is a locking pawl adapted to lock the trigger in the first position when no palm pressure is applied to the palm interlock by the operator.

[0026] A still further aspect of the invention is a reversing switch having first and second settings, the reversing switch connected to the motor, the motor adapted to rotate in a forward and a reverse direction, where the motor is configured to rotate in the forward direction when the reversing switch in the first setting, and where the motor is further configured to rotate in the reverse direction when the reversing switch is in the second setting. [0027] Another aspect of the invention is where the means for limiting the load comprises, a tension arm having distal and proximal ends, the proximal end coupled to the engaging means, where the distal end of the tension arm is adapted to move in a first direction, where the engaging means is adapted to reduce the grip on the rope when the distal end of the tension arm is moved in the first direction, a load bracket having a pivot dowel, a support dowel and a load aperture, the load bracket coupled to the base plate at the pivot dowel, a spring loaded support assembly coupled to the base plate, the spring loaded support assembly adapted to support the load bracket at the support dowel, where the spring loaded support assembly is adapted to react with the distal end of the tension arm, and where the spring loaded support assembly is adapted to move the distal end of the tension arm in the first direction thereby causing the engaging means to reduce the grip on the rope when the load supported in the load aperture exceeds a predetermined amount. [0028] A further aspect of the invention is where the spring loaded support assembly comprises, a pivot bracket having a pivot end and a roller support platform, the pivot end coupled to the base plate, a spring support clevis having a clevis fork and a support rod, the clevis fork coupled to the base plate, where the spring support clevis is positioned under the roller support platform, a spring retainer having a distal end and a proximal end, the distal end having a bore adapted to fit over the support rod, the proximal end of the spring retainer having a flange adapted to fit under the roller support platform, a compression spring adapted to fit between the support clevis and the flange of the spring retainer, a slot in the roller support platform, a platen coupled to the flange of the spring retainer, where the platen is adapted to extend through the slot in the roller support platform, a roller coupled to the support dowel of the load bracket, where the roller is adapted to be supported on the platen when the load supported in the load aperture is below the predetermined amount, and where the roller is adapted to react with the roller support bracket thereby moving the distal end of the tension arm in the first direction causing the engaging means to reduce the grip on the rope when the load supported in the load aperture exceeds the predetermined amount. [0029] Another embodiment of the invention is a base plate, a motor coupled to the base plate, a capstan drum coupled to the motor, where the motor is adapted to rotate the capstan drum, a tension roller bracket having distal and proximal ends and a pivot point between the distal, proximal ends, the tension roller bracket coupled to the base plate at the pivot point, a tension roller coupled to the distal end of the tension roller bracket, a pinch roller coupled to the proximal end of the tension roller bracket, where the pinch roller is positioned to contact the capstan drum, where the rope has an upper region and a lower region relative to the position of the capstan drum, where at least one wrap of rope between the upper region and the lower region of rope is positioned on the capstan drum, where the tension roller is positioned to contact the upper region of the rope, where the pinch roller is configured to apply a gripping force against the at least one wrap of rope on the capstan drum, means for limiting the load coupled to the base plate, where the limiting means is adapted to react with the pinch roller, where the limiting means is further adapted to couple to the load, and where the limiting means is configured to reduce the gripping force on the rope by the pinch roller when the load exceeds a predetermined amount.

[0030] Another aspect of the invention is a channel guide coupled to the base plate and adapted to guide the upper region of rope to contact the capstan drum.

[0031] A further aspect of the invention is an idler roller coupled to the base plate, where the idler roller is positioned adjacent to the capstan drum, and the capstan drum and the idler roller having a plurality of grooves, where the plurality of grooves are adapted to guide the at least one wrap of rope around the idler roller and the capstan drum.

[0032] A further embodiment of the invention is a base plate, a load bracket coupled to the base plate, a motor coupled to the base plate, a capstan drum coupled to the motor, where the motor is adapted to rotate the capstan drum, a tension roller bracket having distal and proximal ends and a pivot point between the distal, proximal ends, the tension roller bracket coupled to the base plate at the pivot point, a tension roller coupled to the distal end of the tension roller bracket, a pinch roller coupled to the proximal end of the tension roller bracket, where the pinch roller is positioned to contact the capstan drum, where the rope has an upper region and a lower region relative to the position of the capstan drum, where at least one wrap of rope between the upper region and the lower region of rope is positioned on the capstan drum, where the tension roller is positioned to contact the upper region of the rope, and where the pinch roller is configured to apply a gripping force against the at least one wrap of rope on the capstan drum when a load is supported by the load bracket. [0033] Another aspect of the invention is a pivot dowel coupled to the base plate, the load bracket adapted to pivot on the pivot dowel, a support dowel coupled to the load bracket, a spring loaded support assembly coupled to the base plate, the spring loaded support assembly adapted to support the load bracket at the support dowel, a tension arm having distal and proximal ends, the proximal end of the tension arm coupled to the proximal end of the tension roller bracket, where the distal end of the tension arm is adapted to move in a first direction, where the pinch roller is adapted to reduce the grip on the rope when the distal end of the tension arm is moved in the first direction, a load aperture in the load bracket, where the spring loaded support assembly is adapted to react with distal end of the tension arm when the load is supported in the load aperture, and where the spring loaded support assembly is adapted to move the distal end of the tension arm in the first direction causing the pinch roller to reduce the grip on the rope when the load supported in the load aperture exceeds a predetermined amount. [0034] A further aspect of the invention is where the spring loaded support assembly comprises, a pivot bracket having a pivot end and a roller support platform, the pivot end coupled to the base plate, a spring support clevis having a clevis fork and a support rod, the clevis fork coupled to the base plate, where the spring support clevis is positioned under the roller support platform, a spring retainer having a distal end and a proximal end, the distal end having a bore adapted to fit over the support rod, the proximal end of the spring retainer having a flange adapted to fit under the roller support platform, a compression spring adapted to fit between the support clevis and the flange of the spring retainer, a slot in the roller support platform, a platen coupled to the flange of the spring retainer, where the platen is adapted to extend through the slot in the roller support platform, a roller coupled to the support dowel of the load bracket, where the roller is adapted to be supported on the platen when the load supported in the load aperture is below the predetermined amount, and where the roller is adapted to react with the roller support bracket thereby moving the distal end of the tension arm in the first direction causing the pinch roller to reduce the grip on the rope when the load supported in the load aperture exceeds the predetermined amount. [0035] Further aspects of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing preferred embodiments of the invention without placing limitations thereon.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) [0036] The invention will be more fully understood by reference to the following drawings which are for illustrative purposes only: [0037] FIG. 1 is a schematic view of the capstan side of a powered rope ascender according to the present invention.

[0038] FIG. 2 is a view of the powered rope ascender shown in FIG. 1 with a rope threaded for ascent.

[0039] FIG. 3A is a schematic view of the motor side of the powered rope ascender shown in FIG. 1 with the controls in a neutral position. [0040] FIG. 3B is a schematic view of the powered rope ascender shown in

FIG. 3A in with the controls in a brake position. [0041] FIG. 3C is a schematic view of the powered rope ascender shown in

FIG. 3A in with the controls in an ascending position. [0042] FIG. 4 is a schematic view of another embodiment of the powered rope ascender shown in FIG. 3A shown with the controls in the neutral position.

[0043] FIG. 5 is a detailed view of the brake lock for the powered rope ascender shown in FIG. 3A.

[0044] FIG. 6A is a detail view of the load limiting assembly on the powered rope ascender shown in FIG. 1.

[0045] FIG. 6B is a detail view of the load limiting assembly shown in FIG. 5A where the load exceeds a predetermined amount.

[0046] FIG. 7 is a cross section view of the drive train assembly of the powered rope ascender shown in FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0047] Referring more specifically to the drawings, for illustrative purposes the present invention is embodied in the apparatus generally shown in FIG. 1 through FIG. 7. It will be appreciated that the apparatus may vary as to configuration and as to details of the parts, and that the method may vary as to the specific steps and sequence, without departing from the basic concepts as disclosed herein.

[0048] FIG. 1 illustrates a schematic capstan side view of a powered rope ascender generally designated as 10. Safety housings are omitted for clarity. Rope ascender 10 has a base plate 12 with a top end 14 and bottom end 16. Although illustrated here as one component, base plate 12 can be assembled from multiple components without departing from the invention. A load limiting assembly 18 is positioned at the bottom end 16 of base plate 12 and will be described in detail in FIG. 5A and FIG. 5B. An up rope fixed channel 20 is attached to base plate 12 with a moveable channel 22 adapted to mate with fixed channel 20. Fixed channel lock 24 is adapted to receive moveable channel lock 26. Moveable channel 22 is illustrated in an open position in FIG. 2. Shoulder pin 30 secures moveable channel 22 in slot 32. Moveable channel 22 is biased open for threading by spring 34 attached to pin 36. Wing 38 is used as a handle to raise moveable channel 22 so that moveable channel lock 26 clears channel lock 24. Threading a rope through fixed channel lock 24 is described in FIG. 2.

[0049] Tension support bracket 40 has center aperture 42, distal spindle 44 and proximal spindle 46 and is supported on base plate 12 at pivot pin 48 with a bushing or rotating sleeve. Distal spindle 44 supports tension roller 50 near the bottom of fixed channel 20 and proximal spindle 46 supports pinch roller 52. A pin 54 is positioned on base plate 12 below fixed channel lock 24 and supports an idler roller 56 rotating on pin 54. Capstan drum 58 is mounted on harmonic drive assembly 60 and is positioned just beneath fixed channel 20 and below idler roller 54. In one embodiment, idler roller 54 is positioned about 30 degrees off vertical from the axis of capstan drum 58. Harmonic drive assembly 60 will be described in the drive train in FIG. 7. Tension roller 50 is positioned so pinch roller 52 will exert a gripping force on capstan drum

58 when force from a tensioned rope between fixed channel lock 20 and capstan drum 58 is applied against tension roller 50. In one embodiment of the invention, capstan drum 58 and idler roller 56 have a plurality of grooves to guide and grip a rope. In a preferred embodiment, idler roller 56 has two grooves and capstan drum 58 has three grooves. Evaluation of prototype ascenders have shown that grooves formed with an included angle of about 30 degrees provides an optimum grip on selected rope. In further embodiments (not shown) capstan drum 58 has one groove or three or more grooves. In a still further embodiment (not shown), idler roller 56 is omitted. Capstan drums with textured gripping surfaces instead of grooves are contemplated in further embodiments. In a preferred embodiment, capstan drum 58 is aluminum and about 4 inches in diameter.

[0050] Below pinch roller 52, tension arm lever 64 (shown behind capstan drum 58) is coupled to tension arm bracket 40 and extends behind load limit bracket 66. Load limit bracket 66 pivots on dowel 68 in base plate 12. When a load is coupled to aperture 70 of load limit bracket 66 and exceeds a predetermined amount, load limit bracket 66 will pivot on dowel 68 and the resultant force against support dowel 72 will cause tension arm lever 64 to move pinch roller 52 away from capstan drum 58 as will be described in further detail in FIG. 6A and FIG. 6B. Down rope guide bracket 74 and down rope spring 76 are mounted at the bottom end 16 of base plate 12. [0051] Rectangular grip opening 80 positioned in base plate 12 near top end 14 forms grip handle 82. Grip handle 82 is configured for gripping by the hand of the operator (not shown). Switch 84 is positioned in grip opening 80 and, in one embodiment, is a key switch to activate powered ascender 10. In other embodiments, switch 84 is a safety switch, or is coupled to a cable remote activation switch or is configured as a radio activated switch. Trigger 86 extends into grip opening 80 and is positioned to be operated by one or more fingers of the operator (not shown). Palm interlock 88 is positioned outside grip handle 82 and is positioned to receive the palm of the operator (not shown). The operation of trigger 86 and palm interlock 88 is described in FIG. 3A through FIG. 3C. Palm interlock 88 pivots on interlock pin 90 in base plate

12. Below interlock pin 90 is brake lock button 92. Reverse button 94 is positioned to slide in groove 96 and is locked in position by detent pin 98. Operation of the aforementioned controls will be described further in FIG. 3A through FIG. 3C. [0052] Linkage housing 100 is attached near top end 14 of base plate 12 and forms part of grip handle 82. Controls enclosure 102 is either formed as part of base plate 12 or attached to the motor side of base plate 12 opposite fixed channel 20. A motor 104 is attached to base plate 12 and mechanically coupled to harmonic drive assembly 60 and capstan drum 58., The drive train for powered rope ascender 10 will be further described in FIG. 7.

[0053] FIG. 2 illustrates powered rope ascender 10 receiving a rope 1 10, shown in dashed line. Rope 1 10 has an upper region 112 and a lower region 1 14 relative to capstan drum 58. Moveable channel 22 is moved up by wing 38 that releases moveable channel lock 26 from fixed channel lock 24. Moveable channel 22 pivots open on pin 30 to provide access for rope 1 10.

Upper region 1 12 of rope 1 10 is threaded between fixed channel 20 and moveable channel 22 and down past tension roller 50 above capstan drum 58. Rope 110 is shown wrapped twice around capstan drum 58 and idler roller 56 and then down capstan drum 58 past pinch roller 52. In another embodiment (not shown), rope 1 10 is wrapped once around capstan drum 58 and idler roller 56. In one embodiment, idler roller 56 is canted to guide rope 1 10 to the adjacent groove in capstan drum 58. Lower region 1 14 of rope 1 10 is passed through down rope guide bracket 74 and threaded through rope spring 76. In one aspect of the invention, tension roller 50 is positioned to cause pinch roller 52 to exert a gripping force on rope 1 10 wound on capstan drum 58 when the tension on the upper region 112 of rope 110 exceeds 10 pounds.

[0054] In another embodiment of the invention (not shown), rope 1 10 is threaded through fixed channel 20, down past tension roller 50, onto capstan drum 58 as an open loop and then directly between pinch roller 52 and capstan drum 58 without looping around capstan drum 58. Then lower region 114 of rope 110 is passed through down rope guide bracket 74.

[0055] In a preferred embodiment, rope 1 10 is a synthetic cordage consisting of a woven or linear core with a knitted outerwear sheath and a 5,200-pound tensile strength. In the embodiment illustrated, powered rope ascender 10 accommodates rope diameters of about 5 mm to about 13 mm with a desired range of about 9 mm to about 13 mm. Note that rope 1 10 can be threaded into powered rope ascender 10 without accessing either end of rope 110. It is to be noted that the invention can be practiced with cable, cord, wire, tubing, hose, strap or other filaments without departing from the teaching herein. [0056] FIG. 3A through FIG. 3C are motor side views of control positions for powered rope ascender 10. Controls are illustrated schematically and linkage housing 100 and a cover on controls enclosure 102 are omitted for clarity. FIG. 3A shows trigger 86 in a neutral position. FIG. 3B shows trigger 86 in a brake position and FIG. 3C shows trigger 86 in a position to energize the motor 104. [0057] In FIG. 3A, controls enclosure 102 has walls that project out from base plate 12 formed in a generally "L "shape with the inside of the "L" adjacent to grip aperture 80. Trigger 86 has trigger handle 120, trigger head 122 and trigger heel 124 as shown. Trigger head 122 has interlock notch 126 towards the front of trigger head 122 and pivot aperture 128 between trigger head 122 and trigger handle 120. Trigger 86 pivots around pivot aperture 128 on a pivot pin mounted in base plate 12. [0058] Palm interlock 88 has a general "L" shape with a handle 130 at the long end of the "L" and a pawl 132 positioned inside the short end of the "L". Pawl 132 is configured to mate with interlock notch 126 on trigger head 122. For safety, palm handle 88 must be pressed inward to disengage pawl 132 from interlock notch 126 before trigger 86 can be moved from the neutral position. Pawl 132 has a pin 134 that supports a tension spring (not shown for clarity) connected to the pin at pivot aperture 128 to keep pawl 132 biased against interlock notch 126.

[0059] Reverse button 94 (shown in FIG. 1 ) is connected to reverse link 140 and is configured to rotate on pin 142. Detent pin 98 through base plate 12 is positioned to secure reverse link 140 in either an up position or down position.

A compression spring (not shown for clarity) is used to bias detent pin 98 down and secure reverse link 140. Reverse control rod 144 is connected to reverse link 140 and reacts with two-position or two setting reverse switch 146 positioned in the upper region of control enclosure 102. In one embodiment, reverse switch 146 reverses the polarity to a DC motor 104 (shown in FlG. 1 ).

In another embodiment (not shown), reverse switch 146 activates a solenoid or other device to reverse direction through a gear drive or air valve coupled to motor 104. In further contemplated embodiments, reverse switch 146 has more than two positions for multiple speeds or other modes of operation. An LED indicator 148 is shown mounted above key switch 84 and is representative of visual indicators of operational status of powered ascender 10. In an exemplary embodiment, visual indicators include an elapsed running time indicator, a capstan drum rotation (distance) indicator, and a power availability (such as battery power or air pressure) indicator. [0060] Returning to trigger 86, a throttle tension link 150 has a proximal end

152 and a distal end 154. Proximal end 152 couples to trigger heel 124. Brake link 156 has a proximal end 158 coupled to distal end 154 of throttle tension link 150, a distal end 160 and a toggle aperture 162 about midway between proximal, distal ends 158, 160. Brake link 156 is supported in upper brake arm bushing 164 and lower brake arm bushing 166 mounted to base plate 12 and within control enclosure 102. Three position switch 170 is mounted in control enclosure 102 and has toggle 172 configured to react with toggle aperture 162. A compression spring 174 is positioned between the bottom wall of control enclosure 102 and distal end 160 of brake link 156 to bias brake link 156 downward.

[0061] Below control enclosure 102 and coupled to distal end 160 of brake link 156 is brake cam 180. Brake cam 180 has distal end 182, pivot point 184, contact point 186 and proximal end 188. Brake cam 180 rotates on a pin in base plate 12 at pivot point 184. Brake cam 180 has a wide section from distal end 182 to contact point 186. In this view, brake cam 180 is biased clockwise by compression spring 174. [0062] Positioned between control enclosure 102 and brake cam 180 is brake arm 190. Brake arm 190 has proximal end 192 to the left and distal end 194 positioned to the right and over brake cam 180. Brake arm 190 is mounted to base plate 12 below controls enclosure 102 on pin 196 at proximal end 192. A brake pad 198 is attached to the lower side of brake arm 190 near proximal end 192. Distal end 194 is positioned between controls enclosure 102 and brake cam 180 to react with the wide section of brake cam 180 as will be described shortly. Compression brake spring 200 shown in hidden line is positioned near distal end 194 of brake arm 190 and is configured to react with the control enclosure 102 and bias brake arm 190 against the upper surface of the wide section of brake cam 180 between distal end 182 and contact point 186. A spring enclosure 202 is positioned on brake arm 190 to keep brake spring 200 in place.

[0063] A brake drum 210 is mounted on the axis of harmonic drive assembly

60 (shown in FIG. 1 ) and has center aperture 212, outside surface 214 and inside surface 216. Brake drum 210 also functions as part of a clutch described in FIG. 7 and is interchangeably referred to as a clutch drum 210. Brake pad 198 is positioned to contact outside surface 214 of brake drum 210 when brake arm 190 is aligned with brake cam 180. [0064] In FIG. 3A, the controls are in a neutral mode. Palm interlock 88 is out so that pawl 132 engages interlock notch 126 holding trigger 86 in the first position. Toggle 172 of switch 170 is in a down position in aperture 162. In this position, the motor is disengaged. Brake cam 180 is rotated in a clockwise position and distal end 182 of brake cam 180 is forcing brake arm 190 upward releasing contact between brake pad 198 and outside surface 214 of brake drum 210. In this position, powered ascender 10 is in freewheel mode allowing brake drum 210 and capstan 58 (shown in FIG. 1 ) to turn freely.

[0065] FIG. 3B illustrates the controls in a brake mode. Palm interlock 88 has been pressed in such as by pressure from the palm of the operator's hand. Pawl 132 is raised to clear interlock notch 126 on trigger top 122. Trigger handle 120 has been moved to the right shown by arrow 220. Throttle tension link 150 and brake link 156 are moved upward as designated by arrow 222.

Toggle 172 of switch 170 is moved to a middle position by the upward motion of brake link 156. In this middle position, the motor 104 (shown in FIG. 1 ) is disengaged. Brake cam 180 is rotated counter clockwise by movement of brake link 156 and is positioned parallel to brake arm 190. Brake arm 190 rotates clockwise on pin 196 by the bias of brake spring 200 as shown by arrow 224 and brake pad 198 contacts outside surface 214 of brake drum 210 (also used as a clutch drum in FIG. 7). In this position, brake drum 210 will not rotate. [0066] FIG. 3C illustrates the controls in an ascending mode. Reverse button 94 is shown in the up position in groove 96. This places the toggle of reverse switch 146 in a down position. Palm interlock 88 has been pressed in such as by pressure from the palm of the operator's hand. Pawl 132 is raised to clear interlock notch 126 on trigger top 122. Trigger handle 120 has been moved to the far right shown by arrow 230. Throttle tension link 150 is moved upward as designated by arrow 232. Toggle 172 of switch 170 is moved to an upper position by the upward motion of brake link 156. This up position engages motor 104 to drive capstan drum 58 (shown in FIG. 1 ). Brake cam 180 is rotated counter clockwise by upward movement of brake link 156 and is positioned so that contact point 186 exerts an upward force on distal end 194 of brake arm 190 as shown by arrow 234. Brake pad 198 is raised away from outside surface 214 of brake drum 210 to release the brake. In another embodiment of the invention (not shown), movement of toggle 172 between the middle position in FIG. 3B and the upper position in FIG. 3C provides speed control to motor 104.

[0067] In a descending mode (not shown), reverse button 94 is positioned in the lower part of groove 96 and the toggle of switch 146 is in an up position. Motor 104 would be energized to operate in reverse. In one aspect of this mode, motor 104 would be configured to rotate at a lower speed in reverse such as about 2 to about 3 ft/sec down the rope. [0068] FIG. 4 illustrates a motor side view of another embodiment of the powered ascender 10 shown in FIG. 3A through FIG. 3C. Distal end 182 of brake cam 180 has part of the wide section removed at position 236 so that when the controls are in the neutral position (as described previously in FIG. 3A), brake arm 190 is rotated downward but brake pad 198 is biased against outside surface 214 of brake drum 210 by brake spring 200. In this embodiment, brake drum 210, and capstan 58, will not rotate when the controls are in the neutral mode (shown here) or in the middle position (shown in FIG. 3B). In order to release brake drum 210 to freewheel, motor 104 must be de-energized (such as switching off key switch 84) and the controls placed in the ascending mode (shown in FIG. 3C). In practice, this embodiment of the invention has two control positions, a brake mode, with or without the palm interlock released, and an ascending mode with the palm interlock released.

[0069] FIG. 5 illustrates a detail perspective view of a brake lock for powered rope ascender 10 shown in FIG. 3A through FIG. 3C. Linkage cover 100 and palm interlock 88 have been removed for clarity. Trigger lock groove 240 is positioned vertically in grip handle 82 and accommodates trigger lock arm 242. Trigger lock arm 242 has distal end 244, and proximal end 246. Lock button 92 on capstan side of base plate 12 is coupled to distal end 244 through an aperture (not shown) in grip handle 82. A pin 248 secures proximal end 246 of trigger lock arm 242 in groove 240 but allows rotation of trigger lock arm 242 perpendicular to base plate 12. Locking pawl 250 has lip . 252 and is positioned on trigger lock arm 242 to engage trigger heel 124 when trigger 86 is in the brake position shown in FIG. 3B. Spring pin 254 is positioned at the distal end 244 of trigger lock arm 242 and supports compression spring 256 that loads against linkage cover 100 (shown in FIG. 1 ). By moving trigger 86 to the brake position (shown in FIG. 3B) and simultaneously pushing brake lock button 92, locking pawl 250 will engage trigger heel 124 and trigger 86 will remain in the brake position without the operator holding trigger 86. Moving trigger handle 120 back slightly allows trigger heel 124 to clear lip 252 of locking pawl 250 and spring 256 will move the distal end 244 of trigger lock arm 242 back into groove 240 where trigger heel 124 can move past pawl 250. [0070] FIG. 6A and FIG. 6B illustrate plan views of load limiting assembly 18 in a loaded and an overloaded condition for powered rope ascender 10.

Down rope guide bracket 74 and down rope spring 76 are omitted for clarity. Load bracket 66 is shown in transparent line for clarity. A rectangular cut out 258 with radiused corners is positioned near the bottom and in base plate 12. Base plate 12 has a horizontal surface 260 adjacent to the left of cut out 258. A load limit support bracket 262 has left flange 264, right flange 266 and cut out 268 and is coupled to base plate 12 at left flange 264 and right flange 266. Left flange 264 is coupled at horizontal surface 260. Cut out 268 has a vertical right edge 270, a horizontal bottom edge 272 and a left edge 274 that slopes outward. In a preferred embodiment, vertical right edge 270 aligns with cut out 258 in base plate 12.

[0071] Load bracket 66 is illustrated as one component for clarity but in a preferred embodiment, comprises two mating components, coupled together at apertures 276 and 278, and positioned on both sides of base plate 12. Load bracket 66 has pivot aperture 280, and roller support aperture 282. Pivot aperture 280 is supported by dowel 68 through base plate 12. Roller support aperture 282 is supported by a spring loaded support assembly described below.

[0072] Pivot support bracket 290 has a roller support platform 292 and bifurcated legs 294 that extend down on each side of load limit support bracket 262 past bottom edge 272. Each leg 294 has an aperture 296 at the bottom that is supported by pin 298 through the bottom of load limit support bracket 262. Roller support platform 292 has a slot opening 300 oriented parallel to base plate 12. and a top surface position 302 that reacts with horizontal surface 260 of base plate 12 and a radiused nose 304 that is configured to react with tension arm 64.

[0073] A spring support clevis 310 has a base flange 312 with a clevis fork 314 below with aligned apertures 316 that receive a pin 318 through the bottom of load limit support bracket 262 below bottom edge 272. Above base flange 312 is support rod 320 shown in phantom. A cylindrical spring retainer 322 has distal end 324 and proximal end 326 with a bore 328 at proximal end 326 configured to fit over support rod 320. Distal end 324 is configured with a top flange 330 having an elongated platen 332 that fits in slot opening 300 and extends above roller support platform 292. A compression spring 334 is positioned between base flange 312 of support clevis 310 and top flange 330 of spring retainer 322. A roller 340 is positioned on platen 332 in cutout 258 of base plate 12 and is coupled to load bracket 66 through dowel 72. In one embodiment (not shown), roller 340 is a needle bearing. In another embodiment (not shown), roller 340 is a slider block and rail or other low- friction element. [0074] In this configuration, compression spring 334 biases top flange 330 against roller support platform 292. Top surface position 302 of roller support platform 292 reacts against horizontal surface 260 of base plate 12.

[0075] In FIG. 6B, an excessive load is placed on load bracket 66 through load aperture 70 as designated by arrow 350. Dowel 72 exerts a downward force on roller 340 proportional to the load in aperture 70. Roller 340 exerts a downward force on platen 332 causing a compression of spring 334. When the load 350 equals a predetermined amount, platen 332 is forced into slot

300 and roller 340 reacts with the top of roller support platform 292. When the load 350 exceeds a predetermined amount, further downward movement of roller 340 causes a rotation of pivot support bracket 290 counterclockwise designated by arrow 352. Radiused nose 304 of load support platform 292 reacts with tension arm 64 moving it outward designated by arrow 354 and releasing the gripping force of pinch roller 52 on capstan drum 58 at the location designated by arrow 356. The load required to move load support platform 292 against tension arm 64 can be determined by the positioning of pivot apertures 280 and 282, different sizes of spring 312 or different depths of platen 332.

[0076] In one mode, load limit assembly 18 will release gripping force momentarily before reengaging pinch roller 52 to reduce shock loading on capstan drum 58 such as when dynamic loads are generated by starting or stopping ascent or descent. In another mode, load limit assembly 18 will prevent a sufficient gripping force for operation with a static load that exceeds a predetermined amount. In one embodiment, load limiting assembly 18 is configured to fully disengage pinch roller 52 when the load exceeds 350-450 pounds. In a further embodiment, load limiting assembly 18 is configured to prevent sufficient gripping force for ascending when supporting a static load exceeding 350 pounds. In a still further embodiment, load limiting assembly 18 is configured to prevent sufficient gripping force for ascending when supporting a static load exceeding 500 pounds.

[0077] FIG. 7 illustrates a cut away cross section view of a drive train for a powered rope ascender. Some components such as base plate 12 and motor 104 are not illustrated in cut section for clarity. Motor 104 is coupled to base plate 12 by a motor housing 360. Motor input shaft 362 is coupled to centrifugal clutch assembly 364 at shoe drive plate 366. Shoe drive plate 366 supports clutch shoes 368 that engage inside surface 216 of centrifugal clutch drum 210 (shown in FIG. 2A as brake drum 210) when motor 104 reaches engagement speed. In one embodiment, centrifugal clutch assembly 364 generates less than 1 inch-pound of torque at less than 1000 rpm and up to 10 inch-pounds of torque at about 3000 rpm.

[0078] In another embodiment (not shown) shoe drive plate 366 is omitted, motor input shaft 362 is coupled directly to centrifugal clutch drum 210 at aperture 212 and motor 104 is configured with sufficient starting torque or an integrated centrifugal clutch. [0079] The output shaft 370 of centrifugal clutch assembly 364 is supported in base plate 12 by bearing 372. Harmonic drive assembly 60 has a harmonic drive system 380 coupled to output shaft 370. Harmonic drive system 380 consists of an asymmetrical wave generator 382, flex spline 384 and circular spline 386. Wave generator 382 is coupled to output shaft 370 and circular spline 386 is coupled to base plate 12. In a preferred embodiment, circular spline 386 is inset into base plate 12. In operation, teeth (not shown for clarity) on the outer surface of flex spine 384 interact with teeth (not shown for clarity) on the inner surface of circular spline 386 as asymmetrical wave generator 382 rotates. Based on teeth configuration, flex spline 384 rotates in the opposite direction of wave generator 382 at reduction ratios typically on the order of 50:1 to about 500:1 or more. In a preferred embodiment, a reduction ratio of about 100:1 is used. Rotation output from flex spline 384 is coupled to spool 390 which is coupled directly to capstan drum 58. In one embodiment (not shown), harmonic drive system 380 is contained in a closed oil bath. [0080] Coupled to circular spline 386 is cylindrical capstan axle 392 having proximal end 394 and distal end 396. Support screws 398 extend through base plate 12 and circular spine 386 and into the proximal end 394 of capstan axle 392 to support harmonic drive assembly 60 and transfer the force moment and torque from capstan 58 to base plate 12. In one embodiment, twelve each number 8 socket screws 398 are mounted in about a 3 inch diameter circle on base plate 12. Distal end 396 of capstan axle 392 forms an annular cap 400 that encloses spool 390. Thrust bushing 402 is positioned between spool 390 and annular cap 398. Thrust bushing 404 is positioned between annular cap 398 and the top of capstan drum 58. Thrust bushings 402 and 404 function to react to the force moment of capstan drum 58 against base plate 12 when supporting a load. In other embodiments (not shown), thrust bushings 402, 404 are combination radial and thrust bearings. [0081] A cylindrical bushing 406 is press fitted on capstan drum 58 and supports the radial loads of capstan drum 58 on capstan axle 392. An O-ring 408 is shown positioned between base plate 12 and capstan drum 58 to seal in lubrication and prevent entry of contamination.

[0082] In other embodiments (not shown), Capstan drum 58 is supported on bearings or bushings where O-ring 408 is positioned and/or spool 390 is supported on bearings or bushings mounted in the opening of annular cap 398.

[0083] In one mode of the invention, harmonic drive system 380 has a 50:1 reduction ratio. In a further mode, harmonic drive system 380 has a 100:1 reduction ratio. In another embodiment of the invention (not shown), planetary gearing or other reduction gear methods are used in place of harmonic drive system 380. [0084] It should be noted that in certain embodiments, capstan 58 can backdrive harmonic drive system 380 when brake pad 198 is released from brake drum 210 and clutch shoes 368 are disengaged, such as when the motor is not rotating. This allows an operator to rotate capstan drum 58 during threading by releasing the brake pad 198 or descend with the motor 104 de-energized using only brake pad 198 against brake drum 210 and friction in harmonic drive system 380 to control descent speed. In a further contemplated embodiment (not shown) clutch shoes 368 are controlled electromagnetically to permit backdrive or control descent.

[0085] In an exemplary embodiment of the invention (not shown), a brushless

DC motor is used for motor 104. Brushless DC motors use electronic commutation of the coils on the stator and are capable of high speeds and torque without arcing. In a further refinement, a sensorless, brushless DC motor is used A sensorless motor must be started with little or no load. The presence of centrifugal clutch assembly 364 allows this motor to start or reverse direction with no load. In a still further refinement, 2-pole, sensorless, brushless DC motor is used. In a further embodiment, a direct drive, brushless DC motor with no gear reduction is used. In another mode of this embodiment, a brushless DC motor with an integral 6.7:1 planetary gear set developing 10 inch-pounds of torque at 6,000 rpm when powered with a 30 cell battery pack operating at 36 VDC is used. In another embodiment, a brush-type DC motor is used. Power for the DC motors mentioned above can be from a battery pack mounted on the ascender, on the operator or both.

Power can also be transmitted from a remote power source through a cable coupled to power ascender 10. In one aspect of the above embodiments, the motor is equipped with reduction gears coupled to the shaft output. In another aspect of the above embodiments, the axis of the motor is mounted at 90 degrees to the axis of the capstan and a worm gear or gear box is used. [0086] In another embodiment, AC power is supplied by cable and an AC motor is used.

[0087] In a further embodiment of the invention (not shown) motor 104 is a compressed gas turbine powered by compressed air. In one mode of this embodiment, motor 104 is a 2.5 inch diameter aluminum impulse turbine, turning at 50,000 rpm. The turbine is driven by compressed gas at 150 psig and develops approximately 2.5 hp. The output of the turbine has a 4.2:1 primary reduction ratio.

[0088] In one aspect of this embodiment, compressed gas is carried on the ascender or by the operator in a compressed gas tank. In another aspect of this embodiment, compressed gas is provided through a hose from a remote source such as a tank or compressor. In a still further aspect of the invention

(not shown), a gas generator such as an chemical cartridge or solid propellant gas cartridge is activated to power the compressed gas turbine. [0089] In a further embodiment of the invention (not shown), motor 104 is an internal combustion engine. In one mode of this embodiment, motor 104 is a two-stroke gasoline engine. In a still further embodiment of the invention (not shown), motor 104 is coupled to powered rope ascender 10 through a cable drive system.

[0090] It is contemplated that in normal use, a belay rope or cable (not shown) will be attached to the operator through a harness and that existing anti-fall devices will be used with the belay rope to ensure safe operation. Although contemplated to support loads while ascending a vertical rope, the invention can be used to maneuver a load on a non-vertical tensioned rope supported between two points including a horizontal rope. The load can be suspended or dragged along a non-vertical surface. [0091] In an contemplated application of the invention (not shown), a powered rope ascender is suspended from a rope (or cable) attached to a portable rescue structure, such as a crane, boom or gantry. The rescue structure with the rope ascender can be moved to the location of personnel requiring extraction such as a pilot in a disabled aircraft. The personnel can access the suspended rope ascender for self extraction or be assisted by rescue personnel suspended by the rope ascender. The rope ascender can also be operated remotely by rescue personnel. Although the description above contains many details, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Therefore, it will be appreciated that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean "one and only one" unless explicitly so stated, but rather "one or more." All structural, chemical, and functional equivalents to the elements of the above-described preferred embodiment that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U. S. C. 1 12, sixth paragraph, unless the element is expressly recited using the phrase "means for."

Claims

CLAIMS What is claimed is:

1. An apparatus for maneuvering on a rope while supporting a load comprising: a base plate; means for engaging a rope; wherein said means for engaging a rope is coupled to said base plate; wherein said means for engaging a rope is configured to grip the rope; a motor coupled to base plate; wherein said motor is adapted to propel said means for engaging a rope relative to the rope; and means for limiting load; wherein said means for limiting load is coupled to said base plate; wherein said means for limiting load is configured to be coupled to a load; and wherein said means for limiting load is configured to reduce the grip on the rope by said means for engaging a rope when the load coupled to said means for limiting load exceeds a predetermined amount.

2. An apparatus as recited in claim 1 , further comprising a motor selected from the group consisting of a DC motor, an AC motor, a brushless motor, a compressed gas turbine, and an internal combustion engine.

3. An apparatus as recited in claim 1 : wherein said motor is coupled to said base plate through a cable drive; and wherein said motor propels said means for engaging a rope through said cable drive.

4. An apparatus as recited in claim 1 , wherein said means for engaging a rope comprises: a capstan drum coupled to said motor; a tension roller bracket having distal and proximal ends and a pivot point between said distal and proximal ends; said tension roller bracket coupled to said base plate at said pivot point; a tension roller coupled to said distal end of said tension roller bracket; and a pinch roller coupled to said proximal end of said tension roller bracket; wherein said pinch roller is positioned to contact said capstan drum.

5. An apparatus as recited in claim 4, wherein when a load is supported on said means for limiting load, said tension roller is configured to contact an upper region of rope that has at least one wrap of rope on said capstan drum, and wherein said pinch roller is configured to simultaneously apply a gripping force against said at least One wrap of rope on said capstan drum.

6. An apparatus as recited in claim 5, wherein said means for engaging a rope further comprises a channel guide coupled to said base plate and adapted to guide said upper region of rope to contact said capstan drum.

7. An apparatus as recited in claim 5, wherein said means for engaging a rope further comprises: an idler roller coupled to said base plate; wherein said idler roller is positioned adjacent to said capstan drum; and said capstan drum and said idler roller having a plurality of grooves; wherein said plurality of grooves are adapted to guide said at least one wrap of rope around said idler roller and said capstan drum.

8. An apparatus as recited in claim 4, further comprising: a harmonic drive coupled between said capstan drum and said motor; wherein said harmonic drive is adapted to reduce the rotation speed of said capstan drum relative to the rotation speed of said motor.

9. An apparatus as recited in claim 8, further comprising: a brake coupled to said base plate; a brake drum coupled between said harmonic drive and said motor; wherein said brake drum has an outer drum surface; and wherein said brake is adapted to engage said outer drum surface.

10. An apparatus as recited in claim 9, further comprising: a centrifugal clutch mounted in said brake drum; wherein said centrifugal clutch is coupled to said motor; and wherein said centrifugal clutch is adapted to reduce the starting torque required by said motor.

1 1. An apparatus as recited in claim 9, further comprising: a control trigger coupled to said base plate; said trigger linked to said brake; said trigger having first and second positions; and a motor control switch linked to said trigger; said motor control switch adapted to energize said motor; wherein when said trigger is in said first position, said brake is engaged with said outer drum surface and said motor is not energized by said motor control switch; and wherein when said trigger is in said second position, said brake is disengaged from said outer drum surface and said motor is energized by said motor control switch.

12. An apparatus as recited in claim 1 1 , further comprising: a palm interlock coupled to said base plate; said palm interlock adapted to react to palm pressure by an operator; wherein said palm interlock is adapted to lock said trigger in said first position when no palm pressure is applied by said operator; and wherein said palm interlock is adapted to allow said trigger to move to said second position when palm pressure is applied to said palm interlock by said operator.

13. An apparatus as recited in claim 11 : said trigger having a third position; wherein when said trigger is in said third position, said brake is disengaged from said outer clutch drum surface and said motor is not energized by said motor control switch; and further comprising a palm interlock coupled to said base plate; said palm interlock adapted to react to palm pressure by an operator; wherein said palm interlock is adapted to lock said trigger in said third position when no palm pressure is applied by said operator; and wherein said palm interlock is adapted to allow said trigger to move from said third position to said first and said second positions when palm pressure is applied to said palm interlock by said operator.

14. An apparatus as recited in claim 13, further comprising: a locking pawl adapted to lock said trigger in said first position when no palm pressure is applied to said palm interlock by said operator.

15. An apparatus as recited in claim 1 , further comprising: a reversing switch having first and second settings; said reversing switch connected to said motor; said motor adapted to rotate in a forward and a reverse direction; wherein said motor is configured to rotate in said forward direction when said reversing switch in said first setting; and wherein said motor is further configured to rotate in said reverse direction when said reversing switch is in said second setting.

16. An apparatus as recited in claim 1 , wherein said means for limiting load comprises: a tension arm having distal and proximal ends, said proximal end coupled to said means for engaging a rope; wherein said distal end of said tension arm is adapted to move in a first direction; wherein said means for engaging a rope is adapted to reduce the grip on the rope when said distal end of said tension arm is moved in said first direction; a load bracket having a pivot dowel, a support dowel and a load aperture; said load bracket coupled to said base plate at said pivot dowel; a spring loaded support assembly coupled to said base plate; said spring loaded support assembly adapted to support said load bracket at said support dowel; wherein said spring loaded support assembly is adapted to react with said distal end of said tension arm; and wherein said spring loaded support assembly is adapted to move said distal end of said tension arm in said first direction thereby causing said means for engaging a rope to reduce the grip on the rope when the load supported in said load aperture exceeds a predetermined amount.

17. An apparatus as recited in claim 16, wherein said spring loaded support assembly comprises: a pivot bracket having a pivot end and a roller support platform, said pivot end coupled to said base plate; a spring support clevis having a clevis fork and a support rod, said clevis fork coupled to said base plate; wherein said spring support clevis is positioned under said roller support platform; a spring retainer having a distal end and a proximal end, said distal end having a bore adapted to fit over said support rod; said proximal end of said spring retainer having a flange adapted to fit under said roller support platform; a compression spring adapted to fit between said support clevis and said and said flange of said spring retainer; a slot in said roller support platform; a platen coupled to said flange of said spring retainer; wherein said platen is adapted to extend through said slot in said roller support platform; and a roller coupled to said support dowel of said load bracket; wherein said roller is adapted to be supported on said platen when the load supported in said load aperture is below said predetermined amount; and wherein said roller is adapted to react with said roller support bracket thereby moving said distal end of said tension arm in said first direction causing said means for engaging a rope to reduce the grip on the rope when the load supported in said load aperture exceeds said predetermined amount.

18. An apparatus for ascending a rope while supporting a load, comprising: a base plate; a motor coupled to said base plate; a capstan drum coupled to said motor; wherein said motor is adapted to rotate said capstan drum; a tension roller bracket having distal and proximal ends and a pivot point between said distal and proximal ends; said tension roller bracket coupled to said base plate at said pivot point; a tension roller coupled to said .distal end of said tension roller bracket; a pinch roller coupled to said proximal end of said tension roller bracket; wherein said pinch roller is positioned to contact said capstan drum; wherein said pinch roller is configured to apply a gripping force against a rope; and means for limiting load; said means for limiting load coupled to said base plate; wherein said means for limiting load is adapted to react with said pinch roller; wherein said means for limiting load is further adapted to couple to the load; and wherein said means for limiting load is configured to reduce the gripping force on the rope by said pinch roller when the load exceeds a predetermined amount.

19. An apparatus as recited in claim 18, wherein when a load is supported on said means for limiting load, said tension roller is configured to contact an upper region of rope that has at least one wrap of rope on said capstan drum, and wherein said pinch roller is configured to simultaneously apply a gripping force against said at least one wrap of rope on said capstan drum.

20. An apparatus as recited in claim 18, wherein said motor is selected from the group of motors consisting essentially of a DC motor, an AC motor, a brushless motor, a compressed gas turbine, and an internal combustion engine.

21. An apparatus as recited in claim 18, further comprising a channel guide coupled to said base plate and adapted to guide an upper region of rope to contact said capstan drum.

22. An apparatus as recited in claim 18, further comprising: an idler roller coupled to said base plate; wherein said idler roller is positioned adjacent to said capstan drum; wherein said capstan drum and said idler roller having a plurality of grooves; and wherein said plurality of grooves are adapted to guide at least one wrap of rope around said idler roller and said capstan drum.

23. An apparatus as recited in claim 18, further comprising: a harmonic drive coupled between said capstan drum and said motor; wherein said harmonic drive is adapted to reduce the rotation speed of said capstan drum relative to the rotation speed of said motor.

24. An apparatus as recited in claim 23, further comprising: a brake coupled to said base plate; and a brake drum coupled between said harmonic drive and said motor; wherein said brake drum has an outer drum surface; and wherein said brake is adapted to engage said outer drum surface.

25. An apparatus as recited in claim 24, further comprising: a centrifugal clutch mounted in said brake drum; wherein said centrifugal clutch is coupled to said motor; and wherein said centrifugal clutch is adapted to reduce the starting torque required by said motor.

26. An apparatus as recited in claim 24, further comprising: a control trigger coupled to said base plate; said trigger linked to said brake; said trigger having first and second positions; and a motor control switch linked to said trigger; said motor control switch adapted to energize said motor; wherein when said trigger is in said first position, said brake is engaged with said outer drum surface and said motor is not energized by said motor control switch; and wherein when said trigger is in said second position, said brake is disengaged from said outer drum surface and said motor is energized by said motor control switch.

27. An apparatus as recited in claim 26, further comprising: a palm interlock coupled to said base plate; said palm interlock adapted to react to palm pressure by an operator; wherein said palm interlock is adapted to lock said trigger in said first position when no palm pressure is applied by said operator; and wherein said palm interlock is adapted to allow said trigger to move to said second position when palm pressure is applied to said palm interlock by said operator.

28. An apparatus as recited in claim 26: said trigger having a third position; wherein when said trigger is in said third position, said brake is disengaged from said outer clutch drum surface and said motor is not energized by said motor control switch; a palm interlock coupled to said base plate; and said palm interlock adapted to react to palm pressure by an operator; wherein said palm interlock is adapted to lock said trigger in said third position when no palm pressure is applied by said operator; and wherein said palm interlock is adapted to allow said^'trigger to move from said third position to said first and said second positions when palm pressure is applied to said palm interlock by said operator.

29. An apparatus as recited in claim 28, further comprising: a locking pawl adapted to lock said trigger in said first position when no palm pressure is applied to said palm interlock by said operator.

30. An apparatus as recited in claim 18, further comprising: a reversing switch having first and second settings; said reversing switch connected to said motor; said motor adapted to rotate in a forward and a reverse direction; wherein said motor is configured to rotate in said forward direction when said reversing switch in said first setting; and wherein said motor is further configured to rotate in said reverse direction when said reversing switch is in said second setting.

31. An apparatus as recited in claim 18, wherein said means for limiting load comprises: a tension arm having distal and proximal ends; said proximal end of said tension arm coupled to said proximal end of said tension roller bracket; said distal end of said tension arm adapted to move in a first direction; wherein said pinch roller is adapted to reduce the grip on the rope when said distal end of said tension arm is moved in said first direction; a load bracket having a pivot dowel, a support dowel and a load aperture, said load bracket coupled to said base plate at said pivot dowel; and a spring loaded support assembly coupled to said base plate; said spring loaded support assembly adapted to support said load bracket at said support position; wherein said spring loaded support assembly is adapted to react with distal end of said tension arm when a load is supported in said load aperture in said load bracket; and wherein said spring loaded support assembly is adapted to move said distal end of said tension arm in said first direction causing said pinch roller to reduce the grip on the rope when the load supported in said load aperture exceeds a predetermined amount.

32. An apparatus as recited in claim 31 , said spring loaded support assembly comprises: a pivot bracket having a pivot end and a roller support platform, said pivot end coupled to said base plate; a spring support clevis having a clevis fork and a support rod, said clevis fork coupled to said base plate; wherein said spring support clevis is positioned under said roller support platform; a spring retainer having a distal end and a proximal end, said distal end having a bore adapted to fit over said support rod; said proximal end of said spring retainer having a flange adapted to fit under said roller support platform; a compression spring adapted to fit between said support clevis and said flange of said spring retainer; a slot in said roller support platform; a platen coupled to said flange of said spring retainer; wherein said platen is adapted to extend through said slot in said roller support platform; and a roller coupled to said support dowel of said load bracket; wherein said roller is adapted to be supported on said platen when the load supported in said load aperture is below said predetermined amount; and wherein said roller is adapted to react with said roller support bracket thereby moving said distal end of said tension arm in said first direction causing said pinch roller to reduce the grip on the rope when the load supported in said load aperture exceeds said predetermined amount.

33. An apparatus for ascending a rope while supporting a load, comprising: a base plate; a load bracket coupled to said base plate; a motor coupled to said base plate; a capstan drum coupled to said motor; wherein said motor is adapted to rotate said capstan drum; a tension roller bracket having distal and proximal ends and a pivot point between said distal and proximal ends; said tension roller bracket coupled to said base plate at said pivot point; a tension roller coupled to said distal end of said tension roller bracket; a pinch roller coupled to said proximal end of said tension roller bracket; wherein said pinch roller is positioned to contact said capstan drum; wherein said tension roller is configured to contact an upper region of rope that has at least one wrap on said capstan drum and wherein said pinch roller is configured to apply a gripping force against said at least one wrap of rope on said capstan drum when a load is supported by said load bracket.

34. An apparatus as recited in claim 33, further comprising: an idler roller coupled to said base plate; wherein said idler roller is positioned adjacent to said capstan drum; wherein said capstan drum and said idler roller have a plurality of grooves; and wherein said plurality of grooves are adapted to guide said at least one wrap of rope around said idler roller and said capstan drum.

35. An apparatus as recited in claim 33, further comprising: a harmonic drive coupled between said capstan drum and said motor; wherein said harmonic drive is adapted to reduce the rotation speed of said capstan drum relative to the rotation speed of said motor.

36. An apparatus as recited in claim 35, further comprising: a brake coupled to said base plate; and a brake drum coupled between said harmonic drive and said motor; wherein said brake drum has an outer drum surface; and wherein said brake is adapted to engage said outer drum surface.

37. An apparatus as recited in claim 36, further comprising: a centrifugal clutch mounted in said brake drum; wherein said centrifugal clutch is coupled to said motor; and wherein said centrifugal clutch is adapted to reduce the starting torque required by said motor.

38. An apparatus as recited in claim 36, further comprising: a control trigger coupled to said base plate; said trigger linked to said brake; said trigger having first and second positions; and a motor control switch linked to said trigger; said motor control switch adapted to energize said motor; wherein when said trigger is in said first position, said brake is engaged with said outer drum surface and said motor is not energized by said motor control switch; and wherein when said trigger is in said second position, said brake is disengaged from said outer drum surface and said motor is energized by said motor control switch.

39. An apparatus as recited in claim 38, further comprising: a palm interlock coupled to said base plate; wherein said palm interlock is adapted to react to palm pressure by an operator; wherein said palm interlock is adapted to lock said trigger in said first position when no palm pressure is applied by said operator; and wherein said palm interlock is adapted to allow said trigger to move to said second position when palm pressure is applied to said palm interlock by said operator.

40. An apparatus as recited in claim 38: said trigger having a third position; wherein when said trigger is in said third position, said brake is disengaged from said outer clutch drum surface and said motor is not energized by said motor control switch; and a palm interlock coupled to said base plate; wherein said palm interlock is adapted to react to palm pressure by an operator; wherein said palm interlock is adapted to lock said trigger in said third position when no palm pressure is applied by said operator; and wherein said palm interlock is adapted to allow said trigger to move from said third position to said first and said second positions when palm pressure is applied to said palm interlock by said operator.

41. An apparatus as recited in claim 40, further comprising: a locking pawl adapted to lock said trigger in said first position when no palm pressure is applied to said palm interlock by said operator.

42. An apparatus as recited in claim 33, further comprising: a reversing switch having first and second settings; said reversing switch connected to said motor; said motor adapted to rotate in a forward and a reverse direction; wherein said motor is configured to rotate in said forward direction when said reversing switch in said first setting; and wherein said motor is further configured to rotate in said reverse direction when said reversing switch is in said second setting.

43. An apparatus as recited in claim 33, further comprising a channel guide adapted to guide said upper region of rope to said capstan drum.

44. An apparatus as recited in claim 33, further comprising: a pivot dowel coupled to said base plate; said load bracket adapted to pivot on said pivot dowel; a support dowel coupled to said load bracket; a spring loaded support assembly coupled to said base plate; said spring loaded support assembly adapted to support said load bracket at said support dowel; a tension arm having distal and proximal ends, said proximal end of said tension arm coupled to said proximal end of said tension roller bracket; wherein said distal end of said tension arm is adapted to move in a first direction; wherein said pinch roller is adapted to reduce the grip on the rope when said distal end of said tension arm is moved in said first direction; and a load aperture in said load bracket; wherein said spring loaded support assembly is adapted to react with distal end of said tension arm when the load is supported in said load aperture; and wherein said spring loaded support assembly is adapted to move said distal end of said tension arm in said first direction causing said pinch roller to reduce the grip on the rope when the load supported in said load aperture exceeds a predetermined amount.

45. An apparatus as recited in claim 44, said spring loaded support assembly comprises: a pivot bracket having a pivot end and a roller support platform, said pivot end coupled to said base plate; a spring support clevis having a clevis fork and a support rod, said clevis fork coupled to said base plate; wherein said spring support clevis is positioned under said roller support platform; a spring retainer having a distal end and a proximal end, said distal end having a bore adapted to fit over said support rod; said proximal end of said spring retainer having a flange adapted to fit under said roller support platform; a compression spring adapted to fit between said support clevis and said flange of said spring retainer; a slot in said roller support platform; a platen coupled to said flange of said spring retainer; wherein said platen is adapted to extend through said slot in said roller support platform; and a roller coupled to said support dowel of said load bracket; wherein said roller is adapted to be supported on said platen when the load supported in said load aperture is below said predetermined amount; and wherein said roller is adapted to react with said roller support bracket thereby moving said distal end of said tension arm in said first direction causing said pinch roller to reduce the grip on the rope when the load supported in said load aperture exceeds said predetermined amount.