Personnel lifting-lowering system

A pulley system particularly useful for lifting or lowering an injured worker includes an upper pulley assembly adapted to be secured to a fixed structure and a lower pulley assembly adapted to be secured to the worker being lifted or lowered and further includes a rope having one end secured to one of the pulley assemblies. The rope is arranged in a substantially conventional manner around the pulleys whereby when a force is exerted on the free end of the rope, the worker can be raised and when a force is removed from the free end of the rope, the worker can be lowered. A pulley wheel forming part of one of the pulley assemblies has outwardly flared internal side walls. The lifting rope passes around the pulley wheel for only approximately 180.degree.. The dimensions of the rope and the pulley wheel are such that the rope engages the side walls of the pulley wheel. The pulley wheel is freely rotatable in a direction that allows the worker to be lifted but is incapable of rotating in the opposite direction when the load is being lowered. As a result, the rope frictionally engages the side walls of the pulley wheel to retard the movement of the rope. A brake prevents movement of the rope in a direction that would allow for descent. The brake is movable between an inoperative position wherein the rope can freely pass therethrough and an operative position wherein the rope can pass through in the ascending direction but not move in the descending direction. The brake is normally biased into the operative position but may be remotely operated to move the same into its inoperative position.

BACKGROUND OF THE INVENTION 
The present invention is directed toward a personnel lifting or lowering 
system and, more particularly, toward such a system which utilizes a 
plurality of pulleys. The system can be used by a worker for lifting or 
lowering himself or herself to or from an overhead position or could be 
used by other workers to lift or lower an injured worker or substantially 
any other load. 
In a wide variety of construction and/or repair projects and in many other 
situations, it is often necessary to lift or lower a substantial load 
through a vertical distance. Not infrequently, a worker may become injured 
while working underground and must be lifted to ground level. Similarly, a 
worker who may become injured while working at an elevated position may 
have to be lowered to safety. The present invention is particularly suited 
for rescuing an injured worker by lifting or lowering him or her. 
One of the more common ways of lifting or lowering an injured worker is 
through the use of a winch or the like. While winches may be effective in 
certain situations, there are other times when they are of little use. A 
winch must be mounted at a fixed position and there must be a worker at 
that fixed position to operate the winch. Thus, if a worker is injured at 
a lower position and the winch is located at an elevated position, any 
worker assisting the injured person must first climb up to the elevated 
position in order to operate the winch. Furthermore, there are times when 
a workman may wish to raise or lower himself and may be physically capable 
of doing so but cannot do so with a fixed winch-type system. 
Pulley systems have also been utilized over the years to lift or lower 
injured workers or other loads. Such conventional pulley systems, however, 
can be rather dangerous and can result in even more serious injuries. 
Conventional pulley systems have no braking systems or the like to prevent 
a free fall in the event that a worker accidentally releases the end of 
the rope. Furthermore, although the pulley system may offer some 
mechanical advantage, the amount of effort involved in operating the same 
can still be great. 
Systems have been proposed which are intended to improve on conventional 
pulley systems that have previously been available. International Safety 
Equipment Inc., of Devault, Pa. for example, offers a personnel lifting 
and lowering system under the name System "99". The System "99" is 
arranged and functions in a manner similar to a conventional pulley system 
but includes a capstan/roller drum at the upper portion thereof. The 
roller drum can rotate in only the lifting direction and is provided with 
means for preventing rotation in the lowering rotation. The lifting rope 
is wrapped two and a half times around the stationary drum to thereby 
provide a friction braking action when a load is being lowered. 
While the ISE System "99" may provide some benefits over conventional 
pulley systems, it may still not be fully satisfactory. Among other 
things, the use of a capstan/roller drum may add unnecessary weight to the 
system. Furthermore, the System "99" does not include a braking means or 
the like for preventing free fall. 
Also available on the market is the GRIP-TECH rescue system by Grip Safety 
& Rescue Systems Corp., of West Seneca, N.Y. The GRIP-TECH system is 
similar to a conventional pulley-type system but includes a brake or 
automatic fall arrester which locks the rope when a predetermined descent 
speed is sensed. While this may provide some additional safety, it does 
not provide the advantages of a constantly applied reverse brake which 
would allow a worker to let go of the lifting rope at any time without 
allowing for any significant movement of the worker being raised. 
SUMMARY OF THE INVENTION 
The present invention is designed to overcome the deficiencies of the prior 
art described above. The pulley system of the present invention is 
particularly useful for lifting or lowering an injured worker and includes 
an upper pulley means which is adapted to be secured to a fixed structure 
and a lower pulley means which is adapted to be secured to the worker 
intended to be lifted or lowered and further includes a rope means having 
one end secured to one of the pulley means. The rope means is arranged in 
a substantially conventional manner around the pulleys whereby when a 
force is exerted on the free end of the rope means, the worker or other 
load can be raised and when a force is removed from the free end of the 
rope, the worker or other load can be lowered. 
A pulley wheel used as part of at least one of the pulley means has 
outwardly flared internal side walls and has the lifting rope passing 
around the pulley wheel for only approximately 180.degree. . The 
dimensions of the rope and the pulley wheel are such that the rope engages 
the side walls of the pulley wheel. The pulley wheel is also mounted so as 
to be freely rotatable in a direction that allows the worker to be lifted 
but is incapable of rotating in the opposite direction when the load is 
being lowered whereby the rope frictionally engages the side walls of the 
pulley wheel to retard the movement of the rope. 
A brake means i s also included for preventing movement of the rope in a 
direction that would allow for descent. The brake means is movable between 
an inoperative position wherein the rope can freely pass therethrough and 
an operative position wherein the rope can pass through in the ascending 
direction but cannot move in the descending direction. The brake means is 
normally biased into the operative position but may be remotely operated 
to move the same into its inoperative position whenever desired.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings in detail wherein like reference numerals 
have been used throughout the various figures to designate like elements, 
there is shown in FIG. 1 a personnel lifting and lowering system 
constructed in accordance with the principles of the present invention and 
designated generally as 10. The system 10 is comprised generally of an 
upper pulley means 12 which, through upper eye bolt 14, is adapted to be 
connected to a fixed structure which may be, for example, at an elevated 
position such as on a bridge or upper floor of a building or may be 
secured at ground level above a manhole opening or the like. 
The personnel lifting and lowering system 10 also includes a lower pulley 
means 16 which, through the use of the eye 18 at the lowermost end 
thereof, is adapted to be connected to a harness or seat 20 or the like 
which, in turn, supports a worker 22 there on. It should be understood, 
however, that this is by way of example only as the pulley system of the 
present invention could be used to lift or lower inanimate loads such as 
construction materials or equipment or the like. 
The upper pulley means 12 is comprised essentially of a housing consisting 
of four depending spaced apart vertical walls 24, 26, 28 and 30. The upper 
ends of the vertical walls 24-30 are secured together through the use of a 
cross bolt 32 connected to the upper eye bolt 14. Knobs 34 and 36 can be 
unscrewed to release the outermost walls 24 and 30, respectively, from the 
cross bolt 32. When the knobs 34 or 36 are removed, the respective side 
wall 24 or 30 is free to rotate about the axle 38 in order to expose the 
interior of the space between the side walls 24 and 26 or the space 
between the side walls 28 and 30. 
A first pulley wheel 40 is mounted on axle 38 between the side walls 24 and 
26. Similarly, a second pulley wheel 42 is mounted on axle 38 between the 
side walls 28 and 30. Pulley wheels 40 and 42 have a generally known 
configuration with tapered internal side walls 44 and 46 and 48 and 50, 
respectively, as best shown in FIG. 4. In the manner described in more 
detail hereinafter, however, the pulley wheels 40 and 42 are capable of 
freely rotating in one direction only about the axle 38. The pulley wheels 
are incapable of rotating in the reverse direction. 
Also pivotally connected to the axle 38 are downwardly extending spaced 
apart plates 52 and 54 which preferably are mounted on either side of the 
walls 28 and 30 as seen most clearly in FIG. 4. Extending downwardly from 
the plate 52 essentially centrally of the upper pulley means 12 is a 
support bracket 56 having an eye 58 formed therein to which is tied one 
end 60 of rope 62. The spaced apart plates 52 and 54 are also used to 
support a brake mechanism 64, the details of which will be described 
further hereinafter. 
The lower pulley means 16 includes a pair of side-by-side pulley wheels 
coaxially mounted for free rotation about axle 66. The first lower pulley 
wheel 68 is shown in phantom in FIG. 1 while the pulley wheel 70, located 
directly behind the pulley wheel 68, is shown in phantom in FIG. 2. 
The rope 62 after being tied to the eyelet 58 passes downwardly around 
lower pulley wheel 70 then upwardly around the first upper pulley wheel 
40. From there, the rope continues downwardly around the second lower 
pulley wheel 68 and again upwardly where it passes through brake mechanism 
64 and around the second upper pulley wheel 42. The free end 72 of the 
rope 62 then extends downwardly again as shown most clearly in FIGS. 1 and 
2. With the exception of the nonreversing features of the upper pulley 
wheels 40 and 42 and the brake mechanism 64, the pulley system thus 
described with the upper and lower pulley means 12 and 16 and the manner 
in which the rope 62 is arranged thereon will function in a conventional 
manner well known in the art. That is, when a downward force is applied to 
the end 72 of rope 62, the lower pulley means 16 and the worker 22 or 
other load attached thereto will be raised with a mechanical advantage of 
4 to 1. Similarly, if a force is removed from the end 72 of the rope 62, 
i.e. if the rope is let out, the worker 22 or other load will be lowered 
or will be allowed to descend. 
As mentioned above, the upper pulley wheels 40 and 42 are mounted on the 
axle 38 so as to be rotatable in one direction only. The manner in which 
this is accomplished is shown most clearly in FIG. 7 which illustrates the 
mounting of the pulley wheel 42 on the axle 38. While only pulley wheel 42 
is being described in detail, it will be understood that pulley wheel 40 
is constructed and mounted in substantially the same manner. 
Referring to FIGS. 4 and 7, it should first be noted that the axle 38 is 
fixed within the upper pulley means 12. That is, it does not freely rotate 
with respect to the remaining component parts thereof and particularly the 
vertical walls 26 and 28. Surrounding the axle 38 in a position 
essentially concentric with the pulley wheel 42 is a ratchet wheel 74. 
Ratchet wheel 74 is fixed to the axle 38 so as not to rotate therewith. 
The side surface of the pulley wheel 42 is provided with a recess 76. A 
pawl 78 is located within the recess 76 and is mounted for rotation about 
a pivot point 80. A spring 82 biases the pawl 78 into the position shown 
in FIG. 7 wherein the teeth at the end of the pawl engage the teeth of the 
ratchet wheel 74 to prevent rotation of the pulley wheel 42 in the 
counterclockwise direction as shown in FIG. 7. As will be seen, this is 
also the lowering or ascending direction of the rope 62. However, when the 
pulley wheel 42 is rotated clockwise as shown in FIG. 7, the front end of 
the pawl 78 is cammed outwardly in the radial direction away from the axis 
38 by the teeth of the ratchet gear 74 and the teeth freely pass 
thereunder so that the pulley wheel 42 can freely rotate in the clockwise 
direction as shown in FIG. 7. This is also the lifting or ascending 
direction caused by an external force being applied to the free end 72 of 
the rope 62. 
The pulley system 10 thus far described is used in the conventional 
following manner. When it is desired to lift a worker 22 or other load, 
all that is necessary is for a fellow worker to pull downwardly on the 
free end 72 of rope 62. Upper pulley wheels 40 and 42 and lower pulley 
wheels 66 and 68 will rotate freely thereby lifting the worker 22. When it 
is desired to lower a worker 22 or other load, the co-worker allows the 
free end 72 of the rope 62 to move upwardly by reducing the force thereon 
in the known manner. The upper pulley wheels 40 and 42, however, lock in 
place and will not rotate in the reverse or descending direction. As a 
result, the rope 62 frictionally engages the upper pulley wheels 40 and 42 
and while the rope is permitted to slide around the pulley wheels, the 
friction causes a drag on the rope which assists the co-worker in lowering 
the worker 22 by reducing the forces which must be applied. 
As shown in FIG. 7, the rope 62 passes only approximately 180 .degree. 
around each of the upper pulley wheels 40 and 42. However, and as shown in 
FIG. 4, the diameter of the rope 62 is such that it engages the side walls 
44, 46, 48 and 50 of the pulley wheels 40 and 42. The rope 62 is, 
therefore, wedged into the pulley wheels thereby increasing the friction 
and drag on the rope in the descending direction. As should be readily 
apparent, because of the outwardly flared shape of the walls 44-50 and the 
diameter of the rope 62, the more force that may be applied by the worker 
22 or other load, the more the rope 62 wedges itself into the pulley wheel 
to again further increase the friction or drag. 
As pointed out above, the pulley system 10 of the present invention also 
includes a brake mechanism 64 through which the rope 62 passes. The brake 
mechanism 64 is pivotally mounted on a rotating plate 84 through pivot 86. 
Plate 84 is, in turn, pivotally secured to the spaced apart plates 52 and 
54 through the pivot or axle 88. This arrangement allows the brake 
mechanism 64 to be moved between an upper or inoperative position as shown 
in FIG. 5 and a lower, operative position as shown in FIG. 6. 
As a result of gravity and the normal movement of the rope 62, the brake 
mechanism 64 is normally biased downwardly into the inoperative position 
shown in FIG. 6. It can, however, be raised into the operative position 
through the use of lever 90 which secured to the plate 84 and which 
extends outwardly therefrom. An elongated cord 92 attached to the end of 
the lever 90 allows the lever to be operated from a remote position. The 
brake mechanism 64 can, however, be maintained in its upper, inoperative 
position, by aligning the apertures 94 and 96 in the plates 84 and 52, 
respectively, and inserting pin 98 therein, obviously, when pin 98 is 
removed, the plate 84 is free to rotate relative to the plate 52. 
As shown most clearly in FIG. 5, when the brake 64 is in its upper or 
inoperative position, the brake shoe or dog 100 moves away from the front 
wall 102 of the brake mechanism thereby allowing space for the rope 62 to 
freely pass therethrough in any direction. When the brake mechanism 64 is, 
however, pivoted downwardly into its lower and operative position as shown 
in FIG. 6, the brake shoe 100 moves toward the front wall 102 of the brake 
mechanism 64 engaging the rope 62. Because of the configuration of the 
surface of the brake shoe 100, the rope 62 can be moved more easily 
upwardly through the brake 64 than downwardly. When being moved 
downwardly, the rope engages the brake shoe and cams the same into an even 
tighter brake. 
The brake mechanism 64 is, per se, well known in the art and is described 
in U.S. Pat. No. 5,156,240, the subject matter of which is incorporated 
herein by reference. More specifically, the brake mechanism 64 is 
constructed in a manner similar to that shown in FIGS. 6 and 7 of the 
prior patent. Accordingly, it is not believed that the details of the 
construction of the brake mechanism 64 need be specifically included 
herein. 
In operation and with the brake mechanism 64 locked into its upper position 
as shown in FIG. 5, the pulley system of the present invention is used in 
the manner described above. That is, when a downward force is exerted on 
the end 72 of the rope 62, the worker 22 or other load is lifted. On the 
other hand, when force is removed from the end 72 of rope 62, i.e. when 
the rope is let out, the worker 22 is lowered and the one-way pulley 
wheels in the upper pulley means 12 reduce the force needed to lower the 
worker. 
In order to utilize the brake mechanism 64, the pin 98 is removed from the 
apertures 94 and 96 and the brake mechanism 64 pivots downwardly into the 
position shown in FIG. 6. This is due to both gravity and the rope 62 
being pulled downwardly by the weight of the worker 22. As the free end 72 
of the rope 62 is pulled, however, the rope moves upwardly pulling the 
brake mechanism 64 upwardly therewith until the brake shoe 100 opens 
thereby allowing the rope 62 to be drawn freely through the brake 
mechanism 64 so that the worker 22 can be lifted. If, however, the pulling 
force is removed from the end 72 of the rope 62, the brake mechanism 
immediately is pulled downwardly into the locking position and the rope 
stops essentially immediately thereby preventing free fall of the worker. 
Obviously, the free end of the rope 72 can be pulled by a co-worker in 
order to lift the worker or, as shown in FIG. 1, the worker 22 may himself 
pull on the free end 72 of the rope. Preferably, he can do this utilizing 
a rope grab mechanism 104 which can easily and freely slide upwardly 
through the rope 62 but which locks onto and grabs the rope in the 
downward direction. The rope grab mechanism 104 is described in detail in 
prior U.S. Pat. No. 5,156,240. 
With the brake mechanism 64 in its operative position as shown in FIG. 6, 
free fall of the worker 22 is obviously prevented. However, if it is 
desired to lower the worker when the brake mechanism is in its operative 
position, this can be done by pulling downwardly on the cable 92 to pull 
the lever 90 downwardly which, in turn, will move the brake mechanism 64 
into its upper or inoperative position. In order to control the descent of 
the worker, controlled downward force on the cable 92 is necessary. That 
is, either the worker 22 himself or a co-worker will pull slowly on the 
cable 92 allowing the rope to slide through the brake and will release 
downward pressure on the cable 92 thereby again engaging the brake if the 
worker begins to descend too quickly. 
The present invention may be embodied in other specific forms without 
departing from the spirit or essential attributes thereof and accordingly 
reference should be made to the appended claims rather than to the 
foregoing specification as indicating the scope of the invention.