Note: Descriptions are shown in the official language in which they were submitted.
T;H 9395CA 2
TITT.E: st~FF~T~nINc; pT ~NK
FTT.T n OF TT-TT~`. TNVENTION
The present invention relates to a work plank for
5 uge in definlng a ralsed work surface. In particular, the
work plank is for use in associatLon wlth access
scaffolding and similar structures.
R~`Rt~T~QTTNn OT~' TTTE INV~NTION
Traditlonally, wooden boards have been used for
deflning work surfaces on scaffolding. These boards can
become damaged and the surface of the boards can
deteriorate, reducing traction. Various metal members have
been secured to the ends of the boards for positively
supporting the boards on a scaffold framework.
There have been a number of steel work planks which
have been proposed where the upper surface of the plank has
been provided with various ports to provide an aggressive
traction surface and to also provide water drainage from
the upper surface of the plank. These steel planks are
typically of a channel shape to provide sufficient
structural stiffness and closed at the ends by hook
arrangements. Examples of such steel planks are shown in
United Kingdom Patent Application No. 2 055 944 and United
Kingdom Patent No. 1 352 697.
In some scaffolding applications, it is difficult
for the scaffolding framework to be set up to follow the
contours of the structure. For example, access scaffolding
can be used to define a work surface about a large
cylindrical storage tank. In these circumstances, it is
often necessary to provide a work surface comprised of
spaced rectangular areas and then use additional work
planks to form a transition surface between these
rectangular areas which more closely follows the contour of
the structure. In this type of system, although the second
surface does improve the safety of the work platform in
that there are less gaps where accidents can occur, the
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work planks at the ends thereof do provide a ledge which
can lead to tripping. In some instances, when using wooden
scaffolding planks, single use, custom fitted, plywood
ramps are nailed to the planks. These ramps form a
5 transitlon between the first work surface and the work
surface supported thereabove.
Although steel work planks have been used, they
have not proven entirely satisfactorily and many
applications still use wooden planks.
SJMM~RY OF TTTF INVFNTION
A work plank according to the present inventlon is
for use in association with work platforms, access
scaf folding, walkways and the like structures and comprises
15 a metal channel having a top surface and opposed sidewalls.
The opposed sidewalls of the plank are angled inwardly to
oppose outward bowing of the sidewalls during loading of
the work plank.
In a preferred embodiment, the top surface has a
20 plurality of openings angled out of the top surface to
provide aggressive traction surfaces.
In yet a further aspect of the invention, the work
plank, at either end thereof, has a hook arrangement for
engaging a cylindrical support. Each hook arrangement
25 continues the channel configuration of the metal channel
and is mechanically secured to the metal channel.
According to an aspect of the invention, each hook
arrangement is secured by mechanical fasteners passing
through the sidewalls with the angled sidewalls providing
30 sufficient clearance for the mechanical fastener to pro~ect
beyond the sidewall while being located within the width of
the top surface of the work plank.
According to a further aspect of the invention, the
sidewalls intermediate the hook arrangement include a
35 keyhole for receiving a key used to fasten two planks
located in a side by side configuration.
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According to yet a further aspect of the invention,
each hook arrangement includes a port through an upper
surface thereof which cooperates with a ramp member to
positively retain the ramp member in an operative position
5 relative to the plank.
BRTR~ D~SCRIPTION OF T~l~. DRAWINGS
Preferred embodiments of the invention are shown in
the drawings, wherein:
~igure 1 is a perspective view of the channel
member of the work plank;
Figure 2 is a partial sectional view of a traction
port along line A-A of Figure 1;
Figure 3 is a partial sectional view along part of
line B-B of Figure 1;
Figure 4 is a partial perspective view of a hook
arrangement about to be received in a channel member;
Figure 5 is a partial perspective view of a hook
arrangement received in the channel member of Figure 1;
Figure 6 is a partial perspective view of a ramp
about to be secured to a work plank;
Figure 7 is a partial perspective view showing a
lower work surface of planks supporting a further work
plank thereabove;
Figure 8 is a perspective view of a tie-down member
used in Figure 6;
Figure 9 is a sectional view of a key securing two
adjacent work planks;
Figure 10 is a sectional view of the channel member
as formed;
Figure ll is a view similar to Figure 10 showing
how the channel adjusts when a hook arrangement is inserted
into the channel member; and
Figure 12 is a top view of a double ramp used to
secure two work planks.
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DETATTlT~n DT~CP~TPTION OF T~IT pRT~T~ERRRn EMPODIMTMTS
The work plank 2 is primarily formed by the metal
channel section 4 having an upper surface 6 and downwardly
and inwardly angled sidewalls 8. These sldewalls have an
inwardly rolled edge 9 which defines a narrow channel 11
between edge 13 and the sldewall 8. Channel ll will serve
to retain a latch member, which will subsequently be
described .
The channel can be made of flat steel which is
rolled to form the channel shape. High strength steel
having a thickness of about .060 thousandth of an inch and
a yield strength of about 50, 000 lb/in2 has proven
satisfactory for many applications.
The upper surface of the work plank 2 has a series
of outwardly pro~ecting holes 14 to provide aggressive
traction on the upper surface and the upper surface also
has a series of reinforcing ribs 18 which are recessed with
a central drainage opening 16. The reinforcing ribs 18
have been found to stiffen the metal channel section 4.
As an alternative to the ribs and drainage port,
the planks can be rolled to form a convex surface whereby
water drains off of the plank. This shape also adds
stif fness .
The sidewalls 8 extend downwardly and inwardly and
this particular configuration has improved characteristics
with respect to the structural strength thereof. By
angling the walls downwardly and inwardly, there is less
tendency for the channel section to fail by outward
.v~ -nt of the sidewalls 8, thereby tending to flatten the
channel, which is a common mode of failure for ~-hAnnel 1 ed
structures. In addition, the downwardly inwardly angled
sidewalls allow adjacent planks to generally abut at the
upper surface with some clearance being provided between
the sidewalls 8. Therefore, if any of the sidewalls become
slightly damaged or the sidewalls are distorted slightly
outwardly, the planks will still abut at the upper edge.
The rolling of the sidewalls at the bottom edge also
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reinforces the plank and essentially defines two rails at
the lower surface. This ls also an improvement, as these
rails act as support rails if one plank is ~tacked atop
another plank or across another plank. This possibility of
5 having planks on top of planks is ~uite common where the
access scaffolding is used to provide a work surface about
an irregular ob~ect, such as a circular tank. Furthermore,
the rails reinforce the plank thereby making it less
vulnerable when transported or stored. The planks
10 preferably are about one foot in width and up to about ten
feet in length.
Loading of the planks tends to force the sidewalls
to distort inwardly, which in turn tends to bow the working
surface of the plank upwardly. This, surprisingly,
15 increases the effective transverse stiffness (side to side)
which allows the plank to be made from thinner material,
thereby reducing weight and cost.
The work plank 2, as shown in Figures 4 and 5,
includes hook arrangements 10 located at opposite ends of
20 the work plank for securement with a cylindrical steel
transom or the like of a scaffold frame. Each hook
arrangement 10 includes a pro ~ecting hook portion 38 for
engaging a cylindrical transom member. Engaging hook
portion 38 includes a port 39 for engaging and retaining a
25 ramp 50.
The sidewalls 8 include diamond shaped keyholes 30
for receiving a fastening key 32, as shown in Figure 9.
The keyhole is preferably at least located in a fixed
central location whereby two work planks in side by side
30 relationship can be tied together and thus deflect together
when a key passe~ through each of the keyholes 30, as shown
in Figure 9. The fastening key 32 is designed to pass
through the keyholes in a first orientation and then be
rotated to a second orientation approximately 90 away from
35 the first orientation, and in this second orientation ties
the work planks together. Keying of the work planks also
serves to maintain the planks in side by side rf~l~t1f~n~h~p
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w 395c~
and forces the planks to deflect together. For example, as
a worker steps down on the center portLon of one work
plank, both planks tend to support each other and
distribute the load, even if the worker is standlng on a
5 single work plank. This is important in that the work
planks can be designed for spans of up to ten feet and
there can be considerable deflection in the center of the
work plank, particularly when the work plank is supported
by transoms at either end. This combined strength
10 obviously includes the effect of a third work plank located
on the opposite side, if present.
As shown in Figures 4 and 5, the angled sidewalls 8
have a securing port 5 through which a self-taping,
fastening member 7 passes to engage port 15 in sidewall 47
15 of the hook arrangement to thereby secure the hook
arrangement at the end of the plank. The angled sidewall 8
of the channel 4 allows the head of the fastener 7 to
pro~ect from the sidewall while still providing full
clearance between adjacent planks ~see Figure 6). The
20 fastener 7 preferably is of a self-tapping design to engage
the sidewall 47 of the hook arrangement as the fastener
passes therethrough. The fastener also pro~ects and is of
a length to locate the wind latch 70. The wind latch 70
has a slot 72 through which the fastener 7 passes. The
25 wind latch is slidable on the fastener 7 and is retained in
the channel 11 and is thus trapped to the work plank (see
Figure 5). In this way, there is no need to have
additional fasteners retain the latch to the work plank and
the wind latch is easily movable along the fastener 7. The
30 latch is movable from a fully locked position where the
latch has the forward edge 74 positioned below a transom of
a scaffoId frame to a clear position shown in dotted lines.
There is no spring loading of the latch, as in some
circumstances, such as for indoor scaffolding, actual
35 latching of the plank may not be required. It can also be
seen that the wind latch 70 ;nf~ 5 a camming surface 76
at the forward end, such that when a work plank is dropped
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on a transom, it is plvotted upwardly and forced into the
work plank to a clear position. In this way, the worker
does not have to manually move the latch to a clear
position. Should the worker wish to latch the plank to the
5 transom, the latch can then be moved to the engaged
pos ition .
Figure 9 shows how the key 32 can engage the
sidewalls 8 of ad~acent side by side work planks 2. By
tying of the work planks together, any outward failing of
10 the sidewalls 8 i5 limited by contact with the ad~acent
work plank and any inward movement of the sidewalls is also
restricted, as the key restricts this movement in the
locked position as the head 35 engages the lower rail of
one work plank and the tail 37 engages the rail of the
15 other work plank. It can also be appreciated that this
lower edge of the work planks is relatively stiff due to
the rails 9.
Details of the hook arrangement are shown in
Figures 4, 5 and 6. Each hook arrangement lO has an upper
20 surface 45 and downwardly extending, inwardly angled
sidewalls 47. The sidewalls 47 are not at a constant depth
and have a tapered portion, generally shown as 49, along
the bottom edge. This allows the hook arrangement to be
initially fed into the end of a work plank, as there is
25 additional clearance due to the tapered edge, and the hook
arrangement will actually tension and move outwardly the
sidewalls 8 of the work plank when it reaches the final
fastening position, as indicated in Figures 10 and 11. In
the final fastening position (Figure 5), the edge 51 is
30 firmly located within the rails 9 of the metal channel 4.
It can also be seen that the hook arrangement includes the
securing port 15 for receivlng the fastener member 7. The
upper surface of the hook arrangement includes stops 53 for
engaging the end of the upper surface 4 of the metal
35 channel member. The hook arrangement 10 is designed to
force the sidewalls 8 of the channel slightly outwardly and
thus pull the upper surface 4 slightly downwardly and into
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WH- 9 3 9 5CA ~ ~
engagement with the upper surface of the hook arrangement
(see Figures 10 and 11). This tensloning of the end of the
work plank makes the hook arrangement and channel 4 f orm a
smooth transition therebetween. The channel 4 is initially
5 extruded in the form of Figure 10 to provide improved
support. The stop 53 also serves to locate the port 15 in
alignment with the ports 5 provided in the sidewalls 8 of
the work plank 2. The engaging hook portion 38 is shown in
top view in Figure 9. The port 39 of the hook portion 38
10 is used for securing of a ramp 80 and can also be used for
fastening a cable used to lift the work plank to a
particular location on the access scaffolding. The hook
portion 38 is offset to one side of the center line of the
work plank and a complementary recess 61 is located to the
15 opposite side of the center line. In this way, two planks
can be secured on a single transom member in an end to end
manner with the hook 38 of one portion of the work plank
recelved ln the recess 61 of the opposite work plank.
The sidewalls of each hook arrangement having an
20 exposed curved recess 91 for accommodating a horizontal
scaffold support with flanges 47 overlying such a
horizontal support and acting as a load bearing surface.
Details of the ramp and its cooperation with the
hook arrangement of a work plank are shown in Figures 6
25 and 7.
Figure 7 shows first work planks 2a with a second
work plank stacked thereabove. The second work plank 2b,
because lt ls stacked on top of the first work planks, has
the ends thereof exposed and could be a hazard as a
30 possible trip surface. For this reason, ramps 80 are used
to provide a transition between the lower supporting work
planks 2a and the second work plank 2b supported
thereabove. The ramp 80 includes a lead-in portion 82 for
insertion beneath the hook arrangement 10 and this lead-ln
35 portion passes beneath the end surface of the recess 61.
Once the lead-in portion 82 has been located, the ramp can
be rotated downwardly such that the pro~ecting hook 84
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Wll- 9 3 9 5CA
passes through the port 39 in the hook portion 38. This
aspect is shown in Figure 6. The ramp 80 includes a recess
85 for recelving the hook arrangement 38 and lncludes a
pro~ecting tongue 87 for coverlng the recess 61 ln the hook
S arrangement 10. Flange 89 ls supported atop surface 45.
The double ramp 80a of Flgure 12 ls used to tle the
ends of two side by side work planks together, although the
ramp can be of the single design of Figure 6 for forming a
transition for a single work plank. The double design of
10 Figure 12, or posslbly trlple or quadruple design, does
provide a common ramp for multiple planks and also ties the
planks together at the ends. The ramp also includes a
sllghtly angled support edge 86 for engaging the lower work
surface .
Figure 7 shows how tie 100 can engage any of the
holes 14 in a lower plank and engage the channel 11 of the
work plank 2b. The tie 100 includes a push in and lock
foot 102 and a securlng head 104. Holes 14 provlde a host
of securlng locatlons whereby tles 100 can malntaln a plank
20 stacked on lower planks ln a deslred locatlon.
The work plank, as described herein, has the
advantage of good strength, hlgh durablllty and resistance
to damage. Furthermore, the plank is secured in a simple
mechanical manner and various parts can be salvaged in the
25 field should some work planks require repalr. The work
plank is easy to assemble and the parts cooperate to
simplify the manufacturlng steps, whlch can elther be
carried out by a manual or automated process. The work
plank provides flexlblllty wlth respect to dlfferent
30 applications and advantageously can be tied to other work
planks to further improve the structural characteristics of
the overall system. This tying of various work planks is
seen with respect to the keying of the work planks as well
as the drop-in multiple ramp which ties the ends of work
35 planks.
The angled sidewalls of the work plank have
lmproved characterlstlcs wlth respect to the deflectlon of
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WH-9395CA
these sldewalls under load and the sidewalls have been
further improved by providing a rail and channel structure
at the bottom edge thereof. The wind latch is held in
place by means of a fastener, which merely passes
5 therethrough, with a latch being retained within a lower
channel at the bottom edges of the work plank. If
necessary, the wind latches can be secured and if not, they
can merely be left in a clear position. The latches are
also designed to move to a clear position when the work
10 plank is placed on a transom support. The hook
arrangements inserted in the ends of the channel members
cooperate to tension the end of the channel member and draw
it into abutment with the upper surface of the hook
arrangements. This provides a smooth transition
15 therebetween.
It has been found that the work plank with the
angled sidewalls provides clearance along the sides of the
work plank when work planks are placed in a side by side
relationship, which is desired to simplify mechanical
20 securement of components along the sides of the work plank.
This structure also ensures that if there is some
deformation of the work plank due to improper handling or
loading, any outward deflection of the sidewalls still
allows the work planks to be placed in a side by side
25 relationship. Thus, with age, the work planks should be
capable of continuing the desired abutting side by side
relationship. The clearance of the angled sidewalls also
ensures that there are not large surfaces in which dirt can
collect, as the point of contact of ad ~acent work planks is
30 merely along the edge thereof. The angled sidewalls also
act as a camming surface during securement of work planks
on scaffolding.
The upper surface 4 of the work planks 2 have a
host of apertures 14 and these apertures can be used to
35 receive a fastening component for tyLng of a stacked work
plank to the work plank therebelow. The fastening member
may pass through a hole in the lower work plank and have a
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pro~ecting portion for engaging a channel or the rail of
the upper work plank. In this way, the work planks can
also be tied, one to the other, when the work planks are
stacked .
A further feature of the invention is the fact that
both the hook arrangement and the metal channel 4 have a
generally open bottom configuration and allow two planks to
partially nest, one within the other, when placed in
opposed relAt~n~h~p This is desirable for efficient
storage and transportation.
Although various preferred embodiments of the
present lnvention have been described herein in detail, it
will be appreciated by those skilled in the art, that
variations may be made thereto without departing from the
1~ spirit o~ the invention or the scope of the appended
claims .
