U.S. patent application number 11/464261 was filed with the patent office on 2007-02-15 for safety aid for sloping roof.
Invention is credited to Paul David Leendertse.
Application Number | 20070034449 11/464261 |
Document ID | / |
Family ID | 35098291 |
Filed Date | 2007-02-15 |
United States Patent
Application |
20070034449 |
Kind Code |
A1 |
Leendertse; Paul David |
February 15, 2007 |
SAFETY AID FOR SLOPING ROOF
Abstract
The aid provides a manner of supporting a plank, on a roof, for
workers to stand on. The plank is carried on plank-jacks, but the
plank-jacks are not attached directly to the roof joists. Rather,
the plank-jacks are suspended via rope-slings from a pair of ridge
saddles, which are firmly and safely secured to the ridge of the
roof. The rope-slings are adjustable, and the worker can very
readily adjust the working level of the plank.
Inventors: |
Leendertse; Paul David;
(Waterloo, CA) |
Correspondence
Address: |
ANTHONY ASQUITH
28-461 COLUMBIA STREET WEST
WATERLOO
ON
N2T 2P5
CA
|
Family ID: |
35098291 |
Appl. No.: |
11/464261 |
Filed: |
August 14, 2006 |
Current U.S.
Class: |
182/45 |
Current CPC
Class: |
E04G 3/26 20130101; E04G
21/3276 20130101; E04G 5/04 20130101; E04G 21/3261 20130101; E04G
5/041 20130101 |
Class at
Publication: |
182/045 |
International
Class: |
E04G 3/26 20060101
E04G003/26 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 15, 2005 |
GB |
0516677.2 |
Claims
1. Apparatus for aiding a worker working on a sloping roof,
wherein: [2] the apparatus includes left and right plank-jacks,
which are physically capable of being used with a plank having
length and thickness, and having a width of at least six inches;
[3] in respect of each one of the plank-jacks: [4] the plank-jack
has a base and a platform; [5] the base of the plank-jack is
physically capable of resting on and against the sloping roof; [6]
the platform of the plank-jack is physically capable of being
firmly fastened underneath the plank, across the width of the
plank; [7] the apparatus includes an attachment-support means, by
means of which a rope-sling can be attached to the apparatus; and
[8] the apparatus is physically capable, when firmly fastened to
the plank, and when a rope-sling is attached to the
attachment-support means, of transmitting to the rope-sling the
weight of the plank-jacks, of the plank, and of a person standing
on the plank.
2. As in claim 1, wherein, each plank-jack weighs less than ten
pounds, and preferably less than five pounds.
3. As in claim 1, wherein the apparatus includes a left
hook-receiving means and a right hook-receiving means, which are
unitary respectively with the left and right plank-jacks, and by
which respective left and right rope-slings can be hooked to the
apparatus and can be unhooked from the apparatus.
4. As in claim 1, wherein, in respect of each plank-jack, the
plank-jack includes a unitary strip of metal, suitably bent such
that a first portion of the strip of metal forms the platform and a
second portion of the same strip of metal forms the base.
5. As in claim 4, wherein the hook-receiving means comprises a
ring, and the ring is attached to the strip of metal.
6. As in claim 4, wherein the base of the plank-jack is of such
physical configuration as to be capable of lying flat against, and
in direct touching contact with, the sloping roof.
7. As in claim 6, wherein the base of the plank-jack includes a
protective bumper of relatively soft material, which, in use, lies
between the strip of metal and the roof.
8. As in claim 1, wherein: [2] the apparatus includes the said
plank; [3] the platform is firmly fastened underneath the plank,
across the width of the plank; [4] the worker being capable of
picking up the plank manually and of carrying the plank up a
ladder, the apparatus is of such negligible weight, compared with
the plank, that, when the two plank-jacks are firmly fastened
underneath the plank, the assembly of plank and plank-jacks jacks
is capable of being picked up, and of being carried up a ladder, as
a unit, manually by the said worker; [5] the apparatus includes an
attachment-support means, by means of which a rope-sling can be
attached to the apparatus; and [6] the apparatus is physically
capable, when a rope-sling is attached to the attachment-support
means, of transmitting to the rope-sling the weight of the
plank-jacks, of the plank, and of a person standing on the
plank.
9. As in claim 8, wherein: [2] the apparatus also includes left and
right rope-slings and left and right roof-fixtures; [3] in respect
of each rope-sling, the rope sling: [4] includes a
top-attachment-structure at an upper-end; [5] includes a
bottom-attachment-structure at a lower-end; [6] includes a length
of rope; and [7] includes a rope-clamp; [8] is of such physical
structure that the distance between the upper-end and the lower-end
of the rope-sling can be shortened or lengthened; and [9] is of
such physical structure that, while a force is applied in the
tensile sense tending to separate the lower-end from the upper-end,
the rope-clamp grips the rope and thereby prevents the lower-end
from moving away from the upper-end; [10] in respect of each
roof-fixture, the roof-fixture: [11] includes a means for attaching
the top-attachment-structure of the rope-sling to the roof-fixture;
and [12] includes a means for attaching the roof-fixture to a roof;
[13] the top-attachment-structure of the rope-sling lies attached
to the roof-fixture; and [14] the bottom-attachment-structure of
the rope-sling lies attached to the attachment-support-means.
10. As in claim 9, wherein, in respect of each plank-jack, the
configuration of the plank-jack is such that: [2] when the base is
resting against the roof, and the plank is attached to the
platform, the platform of the plank-jack provides support for
holding the plank in an at least roughly horizontal plane, and for
preventing the plank from tipping relative to the roof; and [3] the
plank-jack provides the said support simply by resting on the roof,
without being attached to the roof.
11. As in claim 9, wherein the roof-fixture comprises a
ridge-saddle.
12. Procedure for aiding a person working on a sloping roof,
including: [2] providing the apparatus of claim 8; [3] attaching
the roof-fixtures to the roof in a spaced-apart relationship; [4]
attaching the bottom-attachment structures of the rope-slings
respectively to the plank-jacks; [5] attaching the
top-attachment-structures of the rope-slings respectively to the
roof-fixtures.
13. Procedure for supporting a worker on a sloping roof, including:
[2] providing a rope-sling, which includes: [3] a top
attachment-structure and a bottom attachment-structure; [4] a
main-length, being the distance between the attachment-structures
when under tension; [5] a lock, which is effective, at least so
long as there is tension applied to the rope-sling between the
attachment-structures, to lock the rope-sling and to prevent the
main-length of the rope-sling from extending; [6] an operable
unlocker, which is effective, when operated, to unlock the lock,
and thereby to enable the main-length of the rope-sling to be
changed; [7] providing a roof-saddle attached to the roof, which
includes a saddle-sling-attachment means for detachably attaching
the top attachment-structure of the rope-sling to the roof-saddle;
[9] attaching the top attachment-structure of the rope-sling to the
roof-saddle; [10] providing a plank-jack-sub-assembly, which
includes: [11] a plank, plus a plank-jack; [12] a
plank-sling-attachment means for detachably attaching the bottom
attachment-structure of the rope-sling to the plank; [13] the
plank-jack includes a jack-platform and a jack-base; [14] the
jack-platform lies at such angle relative to the jack-base that,
when the jack-base is resting flat against the sloping roof, the
jack-platform is at least approximately horizontal; [15] the plank
is firmly fixed, width-wise, to the jack-platform; [16] the
plank-jack-sub-assembly has the characteristic of being light
enough and manageable enough to be picked up and carried up a
ladder, as a whole unit; [17] providing the
plank-jack-sub-assembly, as a whole unit, away from the roof; [18]
lifting the plank-jack-sub-assembly, as a unit, onto the roof; and
[19] attaching the bottom attachment-structure of the rope-sling to
the plank-sling-attachment means of the plank-jack.
14. As in claim 13, including the worker manually picking up and
carrying the plank-jack-sub-assembly, as a whole unit, up a ladder,
onto the roof.
15. As in claim 14, including: [2] the worker having donned a
safety harness, securing the safety-harness to a harness-saddle,
which is secured to the roof, where the safety-harness and the
harness-saddle are capable of supporting the whole of the worker's
weight; and [3] the worker then standing on the plank, and resting
their weight onto the plank.
16. As in claim 15, wherein the procedure includes the worker
adjusting the position of the plank on the roof, as follows: [2]
the worker transferring their weight away from the plank, thereby
relieving their weight from the plank; [3] with their weight
relieved from the plank, the worker operating the unlocker; [4]
with the lock unlocked, the worker changing the main-length of the
rope-sling; and [5] the worker then transferring their weight back
onto the plank.
17. As in claim 13, including: [2] providing left and right
roof-saddles attached to the roof; [3] providing left and right
rope-slings away from the roof; [4] the worker carrying the
rope-slings up onto the roof, and attaching them to the
roof-saddles; [5] providing the plank-jack-sub-assembly, as a unit,
away from the roof; [6] the worker carrying the
plank-jack-sub-assembly up onto the roof, and attaching the
rope-slings thereto.
Description
[0001] This invention relates to a system for aiding a roof-worker
when carrying out tasks on a sloping roof.
BACKGROUND TO THE INVENTION
[0002] The dangers of working on a sloping roof--during
construction work for example--are all too clear. Numerous systems
have been proposed, and are in place, for safeguarding workers.
However, these systems involve compromises between safety and
convenience, and it is left to supervisors to check that the
systems are constantly in use. Traditionally, the systems that
offer convenience are not inherently safe, and the systems that
offer safety are not inherently convenient.
[0003] It is an aim of the invention to provide a system that is
highly convenient for the worker to use, and at the same time is
inherently safe.
[0004] The conventional screwed-down ridge-saddle does represent an
inherently safe manner of securement, in that it is shaped to fit
the ridge of the roof. The ridge-saddle takes support from the
geometry of the ridge, so that even if the fixing screws (or nails)
might be loose, they are unlikely to be actually pulled out. This
type of inherent safety is in keeping with the aims of the
invention.
[0005] The conventional ridge-saddle includes a ring, and typically
the roof worker attaches a personal safety harness to the ring.
[0006] By contrast, conventional plank-jacks are not inherently
secure. Traditionally, these jacks are nailed to the sloping roof,
the nails passing through the plywood sheathing and into the roof
joists. The problem with this is that the worker can think the jack
is secure, but actually it is only nailed to the plywood sheath
panel, not to the joist. It would be almost less dangerous for the
jack to be secured not at all, than for the jack to appear to be
secure when it is not actually and fully secure. Many injuries have
been caused by plank-jacks giving way unexpectedly.
GENERAL FEATURES OF THE INVENTION
[0007] The invention makes use of the kind of inherent security
that is present in the conventional ridge-saddle. The plank-jacks
are preferably not attached to the roof at all, but rather are
supported on rope-slings from the ridge-saddles.
[0008] The rope-slings are adjustable as to length, whereby the
worker can very readily adjust the level of the plank. The worker
can simply readjust the level of the plank, as work progresses,
over the whole surface of the roof. As compared with the
conventional ways by which workers can safely carry out tasks on
roofs, the system of the invention permits large savings in time,
and efficiency.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0009] By way of further explanation of the invention, exemplary
embodiments of the invention will now be described with reference
to the accompanying drawings, in which:
[0010] FIG. 1 is a cross-sectioned side elevation of a roof of a
building under construction, to which a system that embodies the
invention is applied.
[0011] FIG. 2 is a front view of a ridge-saddle component used in
the system.
[0012] FIG. 3 is a pictorial view of the roof of FIG. 1, showing
more of the components used in the system;
[0013] FIG. 4 is a view corresponding to FIG. 1, at another
location on the roof.
[0014] FIG. 5 is a front view of a plank-jack component used in the
system.
[0015] FIG. 6 is a view similar to FIG. 4, showing some aspects of
the geometry of the plank-jack.
[0016] FIG. 7 is a view similar to FIG. 6, showing another
plank-jack.
[0017] The scope of the invention is defined by the accompanying
claims, and not necessarily by specific features of exemplary
embodiments.
[0018] The drawings show items of apparatus that have been
configured and arranged for use in a roof-working aid system that
embodies the invention. The apparatus as shown in the drawings is
intended to be used after the frame of the roof has been erected
and is secure. The safety aspects of the working aid system make
use of the integrity of the roof frame.
[0019] The aid system can be used for the task of applying the
plywood sheath or cover over the frame, and for the task of
attaching the shingles or roofing tiles over the cover. The system
can also be used after the roof has been finished, for example for
such tasks as repairing or re-shingling a roof, for installing
skylights, and the like.
[0020] In FIG. 1, a sloping roof 20 comprises a frame of wooden
studs 23, to which a cover sheet 24 of plywood has been secured.
The support system makes use of a ridge-saddle 25 (shown in side
view in FIG. 2). The worker secures the ridge-saddle 25 to the
studs at the ridge of the roof, e.g by screws 26.
[0021] The ridge-saddle 25 includes a ridge-ring 27. The
ridge-saddle, with ridge-ring, is conventional in itself, being a
proprietary safety item that is in widespread use for receiving
safety harnesses and other items, for on-roof work. In the
traditional usage of the ridge-saddle, the worker, having donned a
safety harness, snags a hook of the safety harness onto the
ridge-ring 27 of the ridge-saddle 25.
[0022] As shown in FIG. 3, the worker secures two of the
ridge-saddles 25 to the roof ridge in a spaced apart
relationship.
[0023] The roof-working aid system also makes use of a plank 28.
Typically, this would be of wood, e.g two inches by ten inches (one
inch=2.54 cm), and e.g ten feet long (1 foot=30.48 cm). To the
plank 28 are secured two plank-jacks 29. One of the plank-jacks 29
is shown in FIGS. 4,5.
[0024] The apparatus being configured for use in the roof-working
aid system of the invention, the plank-jack 29 need not be fastened
directly to the roof. The system makes use of the fact that the
ridge-saddle 25 is secured to the roof--the ridge-saddle has to be
provided, and secured, in any event (often, its provision is
dictated by safety codes), when persons are working on the roof, to
support the safety harnesses of the workers.
[0025] The plank-jack 29 includes a rigid steel strip, which is
bent to the profile shape as shown in FIG. 4. This shape includes a
base 30, a brace 32, and a platform 34. The plank 28 is bolted to
the platform 34. At the top end of the base 30, the strip is formed
with an eye 31, in which is secured a plank-ring 35. The platform
34 is fastened to the base 30, at 33; the manner of fastening may
be permanent (e.g by welding), or may be dismantlable, whereby the
angle the platform 34 (and the plank 28) makes with the base 30 can
be adjusted.
[0026] The plank-ring 35 is suspended from the ridge-ring 27 by
means of a rope-sling 36. The rope-sling 36 includes a rope 37, and
an adjustable rope-clamp 38. The upper end of the rope 37
terminates at a top-hook 39, and an upper hand-grip 40 facilitates
manipulation of the top-hook 39 into engagement with the ridge-ring
27. A lower hand-grip 43 is fastened to the rope-clamp 38, and
terminates in a-bottom-hook 45, which is engageable with the
plank-ring 27.
[0027] The rope 37 passes between clamping members inside the
rope-clamp 38, whereby when the rope-sling 36 is loaded in tension,
as shown in FIG. 3, the rope-clamp 38 grips the rope 37, preventing
elongation of the rope-sling 36. The length of the rope-sling 36
(i.e. the distance from the top-hook 39 to the bottom-hook 45) can
be shortened by lifting the tail 46 of the rope 37, and pulling the
tail 46 upwards relative to the rope-clamp 38. This action releases
the clamping members inside the rope-clamp mechanism enough to
enable the rope to slide through the rope-clamp 38.
[0028] It is possible to shorten the rope-sling--by pulling upwards
on the tail 46--even though there is still tension in the rope 37.
To lengthen the rope-sling, this is done by first taking away
tension in the portion of the rope that passes through the
rope-clamp 38. Now, the rope 37 can slide through the rope-clamp 38
in the lengthening direction--or in the shortening direction, of
course. The worker can readily support their weight by holding on
to the rope 37, above the rope-clamp 38, with one hand; the other
hand can then be used to manipulate the slack rope (i.e. the
portion of the rope below the first hand) through the rope-clamp.
As soon as the rope-clamp 38 is put (back) in tension, the clamping
members grip the rope and prevent further elongation. The
rope-sling 36, as described, is conventional in itself, being a
proprietary safety item that is in widespread use for on-roof
work.
[0029] In order to carry out the task of affixing shingles to the
roof, the worker first positions the apparatus with the plank 28
close to the eave line 47, as shown in FIG. 3. (Note: the lines 48
are often actually marked on the roof, being carefully laid out as
an aid to correctly positioning the shingles.) The worker now
affixes the bottom row of shingles while squatting or kneeling on
the plank, and leaning downwards. Once the bottom row of shingles
is in place, the worker then lowers the plank, so now the plank 28
is resting on the shingles just installed.
[0030] As mentioned, the worker cannot lower the plank 28 (i.e.
cannot lengthen the rope-sling 36) until all weight is taken off
the rope-clamp. The worker can make use of the fact that they have
a safety harness, which is hooked into the ridge-ring 27; the
worker can support themself with one hand by hanging from the
safety harness, to take their weight off the plank, for a few
moments, to enable lowering the plank. Of course, shingling is done
from the bottom up, which entails progressively shortening the
rope-slings 36. The need to lengthen the rope-slings 36 arises only
occasionally.
[0031] With the plank 28 set at the right height, the worker can
stand on the plank, and can proceed to install the rest of the
shingles on the roof. From time to time, as they proceed up the
roof, the worker simply shortens the (two) rope-slings 36 and
raises the plank 28. Thus, the worker would shorten the rope-slings
36 after having installed a few rows of shingles. It may be noted
that it is so easy, with the system as described herein, as
compared with traditional systems, for the worker to shorten the
rope-slings, that the worker might even contemplate shortening the
rope-slings after each row. It has been found that workers can do
this with very little practice, in a very rapid and efficient
manner. Complete safety can never be guaranteed, but it can be
asserted that the chance of an accident, when using the apparatus,
even if the worker approaches the work perhaps with less than the
usual skill and attentiveness, is very much reduced, as compared
with the traditional manner by which roofing shingles are
installed.
[0032] On a gently sloping roof, i.e. a roof on which the worker
can walk about, the worker can simply stand on the roof (as
distinct from hanging on their safety-harness), thereby relieving
the plank and the rope-clamp of weight, and enabling the length of
the rope-sling to be adjusted.
[0033] In FIG. 4, the base 30 of the plank-jack 29 is shown resting
flat against the sloping roof 20. In the traditional systems, the
equipment used was highly likely to mark and mar the just-laid
shingles upon which it rests, and, though reduced, this tendency
can still be present in the present system. So, a bumper of e.g
rubber may be secured to the undersurface of the base 30, to
protect the shingles.
[0034] The plank 28 being attached to the plank-jack 29, as
mentioned the angle 49 (FIG. 4) at which the plank rests is
determined by the angle 50 between the base 30 and the platform 34.
The angle 49 at which the plank rests is determined also, of
course, by the slope of the roof. If the slope of the roof were
steeper, in FIG. 4, the plank would be tilted over in the clockwise
sense. From the safety standpoint, the plank should not be angled
further in the clockwise sense than horizontal; in other words, the
apparatus should not be used when the slope of the roof is steeper
than the angle 50. It is not so much of a safety problem for the
plank to be tipped or tilted the other way (i.e. inwards). To suit
most roofs likely to be encountered, the angle 50 should be between
forty-five and thirty degrees.
[0035] Preferably, the width of the plank 28 should be no more than
the width of the platform 34; if the plank were to overhang to the
right, in FIG. 4, more than about say an inch, that might be
unsafe, in that the worker might be able to apply their weight to
the plank in such manner as to tip or tilt the plank clockwise
(outwards). Preferably also, the base 32 should be so arranged as
to make it difficult or impossible for the worker to so apply
weight to the plank that the plank tends to tip clockwise. The
length of the base 30 should be such that the lowermost extremity
53 at which the base touches the roof lies well to the right of the
centreline of the plank. However, it is not difficult to achieve
the correct dimensions and configuration such that the plank is
very stable and safe.
[0036] FIG. 6 shows the relationships the designer should bear in
mind. The prudent designer will cater for the worker standing such
that their weight W acts at the outermost edge 56 of the plank 28.
Standing thus, the worker applies a tipping moment to the plank,
equal to the worker's weight W multiplied by the overhang distance
H. This tipping moment tends to make the plank-jack 29, and the
plank 28, pivot clockwise about the point 53. The tipping moment is
resisted by the moment tending to tip the plank the other way,
which is equal to the tension T in the rope-sling 36 multiplied by
the offset distance R. If clockwise tipping were to start, the
offset distance would increase, so that a position of equilibrium
presumably would be reached where the product of T.times.R is equal
to the product of W.times.H. However, even though tipping right
over might be a very remote possibility, of course any tipping at
all is undesirable. The offset R therefore should be large enough
that the equilibrium position of the apparatus is with the base 30
of the plank-jack 29 resting flat against the roof surface 20, no
matter where the worker stands on the plank 28.
[0037] Preferably, the designer should set the distance R at
between one inch and four inches, and the distance H at no more
than six inches (and preferably zero inches).
[0038] When fixing the bottom-most row of shingles, the worker
might position the plank-jacks a few inches above where the bottom
row will be affixed; then, the worker would kneel on the plank and
would lean out and over the plank, and would reach down, below the
level of the plank, to carry out the work of fixing the lower-most
row of shingles. The designer should make sure that the plank
remains stable even under this manner of loading. Again, it is
recognised that a geometry that has that result, over a wide range
of roof slopes, is easy enough to engineer.
[0039] It might be possible, theoretically, for the plank to tip
the other way, i.e to rotate anti-clockwise in FIG. 4. However, it
is simple to engineer the plank-jack such that the possibility of
such a condition arising is very remote.
[0040] It may be noted that, in the traditional plank-jacks, the
plank-jack was nailed to the roof. Therefore, although the
plank-jack was much less secure, as explained, as regards the
possibility of its (suddenly) tearing free, at least, while it was
in place, the nailed-down plank-jack did not tend to tip. The new
plank-jack, as described herein, is not nailed to, or otherwise
attached directly to, the roof, and therefore the designer has to
take precautions against tipping. However, as explained, it is
simple for the designer to ensure that tipping is not a
problem.
[0041] It will be understood that the plank could not conveniently
be attached to the plank-jacks, in a system in which the
plank-jacks were fastened (e.g by nails) to the roof, because the
plank would be in the way when inserting (and especially when
removing) the nails from underneath the plank. In the present
system, the plank-jacks should be securely bolted to the
plank-jacks, and may be left so for the life of the plank. (Wooden)
planks have a relatively short,life, but the (metal) plank-jacks
can be expected to last indefinitely.
[0042] As mentioned, the base 30 of the jack may be provided with a
soft bumper for actual contact with the roof. The base 30 may also
be provided with upturned ends, or ski-ends, as shown at 57 in FIG.
7, in order to alleviate the possibility of the ends of the base
digging in and marring the surface of the roof.
[0043] As shown in FIG. 5, the plank-jacks 29 should be positioned
at almost the very ends of the plank 28; if the plank were to
overhang outside the plank-jack 29, the worker might upset the
plank if they were to stand on the overhanging portion. On the
other hand, a sixteen-ft long ten-by-two wooden plank weighs almost
as much as the worker; so the risk of the plank being upset if the
worker were to stand on the overhanging end is more theoretical
than real. In fact, many roofs are angled and gabled such that the
ability of the worker to stand on a portion of the plank that lies
a foot or two outside the plank-jack can be very convenient. Of
course, the worker should not be encouraged to think that standing
outside the plank-jacks is risk-free. But the temptation to do so
is high, and with the present design it is recognised that such
standing is not particularly risky. Again, at most work sites,
there is a rule that roof-workers must always be secured by a
safety harness.
[0044] The strip of metal that forms the plank-jack 29, i.e the
component to which the plank is attached, as shown is directly
attached to the plank-ring 35. However, that is not essential; in
an alternative version, the plank-ring is carried on a separate
bracket that is bolted to the plank. In FIG. 7, the plank-ring is
formed from an eye-bolt 58, which passes through a hole drilled in
the plank, aligned with a corresponding hole in the platform 34.
The strip of metal preferably is between one inch and four inches
wide.
[0045] The plank need not be attached to the plank-jacks by being
through-bolted thereto, as shown in the drawings. However, the
plank should be firmly fastened to the plank-jacks; that is to say,
when fastened, the plank-jacks should be incapable of independent
movement with respect to the plank, under all conditions of
loading, including a certain degree of abusive loading, such as
might be encountered in use.
[0046] The system described herein is for aiding a person to carry
out tasks on a sloping roof. It will be appreciated that the task
of setting up the apparatus is a key aspect as regards the
efficiency with which the overall roofing task can be carried out.
The smaller the number of journeys up and down the ladder that it
takes for the worker to set up the equipment, the better, from the
efficiency standpoint.
[0047] With the present system, typically, the worker can carry the
equipment up in just two journeys up the ladder, as follows. It
will usually be the case that the ridge-saddles 27 are already
securely attached to the ridge of the roof, but the worker should
first see to it that the ridge-saddles are strategically placed
where needed on the roof. The worker prepares the (two) rope-slings
on the ground. The worker can easily pick up the rope-slings
manually, and can carry them up the ladder onto the roof. The
worker hooks the top-attachment-points of the rope-slings to the
ridge-saddles. The worker can also easily carry any odds and ends
of equipment, on this journey.
[0048] Next, the worker returns to the ground, and prepares the
plank and the plank-jacks, on the ground. The plank-jacks might
already be bolted to the plank, or the worker can perform this task
at this point, and should at any rate ensure that the bolts are
tight and secure. When the plank-jack-sub-assembly has been
constructed and inspected, the worker picks up the
plank-jack-sub-assembly, as a whole unit, and carries the
sub-assembly up the ladder. The worker should not be required to
carry anything else other than the plank-jack-sub-assembly, on this
journey. Of course, not every person can carry a sixteen-ft long,
100-pound plank up a ladder, but roof-workers typically are readily
capable of such a task. The extra weight of the plank-jacks is only
a few pounds, which makes virtually no difference to whether the
worker can carry the sub-assembly up the ladder.
[0049] When using the present system, it is a simple matter also
for the worker, after completing a section of roof, to move the
equipment to the next section. The worker can unhook the left
rope-sling from the left ridge-saddle, and hook the left
rope-sling, temporarily, to the right ridge-saddle, so both
rope-slings are suspended from the right ridge-saddle. Then, the
worker unhooks the right rope-sling, and moves it to the next
available ridge-saddle to the right, and the task of moving the
equipment is complete.
[0050] With other systems, by contrast, the worker is forced to
make three or even four journeys up and down the ladder in order to
take the equipment from the ground onto the roof. With other
systems, also, the worker must take at least part of the equipment
down the ladder, and back up again, in order to move it to a new
location on the roof. On a typical roof, it is rarely possible to
get away with moving the equipment only six times, and more times
are required if the roof is large and/or complicated. Therefore,
the importance will be appreciated of the rapidity with which the
equipment can (safely) be deployed.
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