Note: Descriptions are shown in the official language in which they were submitted.
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TITLE: SCAFFOLD POST SLEEVE
FIELD OF THE INVENTION
The present application relates to a scaffold post having a
twist lock coupling sleeve.
BACKGROUND OF THE INVENTION
Most scaffolding systems include scaffold posts connectable in
an end to end manner to form an upright support column.
Typically, a spigot-type arrangement is inserted in and forms
the mechanical connection between the lower scaffold post and
the upper scaffold post. In some scaffolding systems, the
spigot is an integral part of the top portion of the scaffold
post often formed by seeming to provide the diameter. The
bottom portion of the scaffold post is formed to be slightly
enlarged or bell mouthed to closely receive the spigot.
Other scaffolding systems use a separate spigot member that is
inserted in a lower end of an upper scaffold post, and a lower
portion of the spigot is inserted in the upper end of the
lower scaffold post. Typically, the spigot is attached by a
removable gravity lock pin, such as a pigtail pin, to the
lower portion of the upper scaffold post. A clevis pin may be
used to secure the spigot to the upper portion of the lower
scaffold post such that the scaffold posts abut end to end.
With independent spigot arrangements as well as the integral
spigot, there is often a requirement to provide a positive
lock of the scaffold posts to each other. In case of the
integral spigot arrangement, this is typically a gravity lock
pin, such as a pigtail pin, inserted through a port in the
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upper scaffold post, and through an aligned port in the spigot
portion such that the pin passes from one side of the scaffold
post to the other side. This gravity lock pin forms a positive
lock of the scaffold posts one to the other. In the case of an
independent spigot, a clevis pin may be used to mechanically
secure a bottom portion of the spigot to the lower scaffold
post, and a gravity lock pin typically secures the upper
scaffold post to the upper portion of the spigot. My earlier
patent CA 2,638,365 discloses a spigot configured with a twist
lock collar. This arrangement is desirable but is generally
not compatible with existing scaffold post systems.
Although scaffolding systems are designed to allow mechanical
securement of the scaffold posts one to the other (by bolts
for example), this procedure is not always completed, creating
a significant safety risk. Safety inspectors often shut down a
job site until such safety procedures are complied with.
While having vertical members that lock together easily would
be a much sought-after improvement, compatibility with
existing scaffold products is advantageous. The present
invention provides a system compatible with many existing
scaffold products while simplifying the securement of stacked
scaffold posts.
SUMMARY OF THE INVENTION
A scaffold assembly according to the present invention
comprises a top post having, adjacent a bottom edge, at least
one projection directed outwardly from a surface thereof, a
bottom post and a coupling sleeve connected to the bottom post
and having at least one receiving slot for receiving the
projection and at least one locking slot. The projection is
movable between a receiving position that allows the at least
one projection to be received within the receiving slot and a
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locking position where the projection is positioned and
maintained within the locking slot.
In an aspect of the invention, the projection is moved between
said receiving position and said locking position by rotating
said top post about its longitudinal axis.
In a further aspect of the invention, the coupling sleeve
includes a port to receive a locking pin.
In yet a further aspect of the invention the coupling sleeve
is at least 6 inches long.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention are shown in the
drawings, wherein:
Figure 1 depicts a scaffold post assembly;
Figure 2 depict the twist lock arrangement receiving a
regular upper post without projections;
Figure 3 depicts and unassembled scaffold post assembly
including a upper post with locking projections;
Figure 4 depicts an assembled scaffold post assembly;
Figure 5 depicts a series of cross sections through the
square top portion of the twist lock assembly wherein 5 a
depicts the receipt of the projects in the receiving slots, 5b
depicts the projections entering the locking slot and 5c
depicts the projections in the locked position;
Figure 6 depicts an upper post without projections
inserted into a lower post with a twist lock assembly;
Figure 7 depicts an upper post without projections
inserted into a lower post with a twist lock assembly with a
pigtail pin inserted through both the upper and lower posts;
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Figure 8 depicts an alternative embodiment of the
invention wherein the twist lock assembly includes and
`L'shaped slot.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Figure 1 depicts a scaffold post assembly 2 having an upper
post 4 and a lower post 6. The upper post 4 and lower post 6
can be identical. Both the upper and lower posts are adapted
to receive screw jacks, bases, top plates etc. either end
thereof or connect with like scaffold posts. The scaffold
posts 4 and 6 each include a connecting sleeve 10 fixed to the
upper end thereof. The connecting sleeve 10 of the lower post
receives a lower end of the upper post. The upper end of each
post includes a twist lock arrangement 8. The connecting
sleeve 10 includes a locking collar 12. The locking collar
12 includes at least one receiving slot 14 for receiving a
locking projection 16 on the upper scaffold post 4 as shown in
Figure 3. The connecting sleeve 10 extends substantially
below the square locking collar 12 in order to provide a
length of sleeve that closely fits the outside diameter of the
lower portion of the upper scaffold post 4 and forms a strong
mechanical connection therebetween. The length of the
connecting sleeve provides structural support to the joint of
the upper scaffold post 4 to the lower scaffold post 6.
Although a variety of lengths are known to a person skilled in
the art, the preferred length is about 6 inches.
The top of the post 6 is fitted with the connecting sleeve 10
and the twist lock arrangement 8. Various methods of securing
the connecting sleeve and twist lock arrangement to the post
can be used however it is preferable to weld the twist lock
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arrangement 8 to the connecting sleeve 10 that is welded to
the top of the scaffold post 6.
The bottom end of the post includes at least one projection 16
that will engage with the at least one slot 14 in the square
top portion of the twist lock arrangement. The projection 16
is shown of the upper post 4 in figure 1. The square
configuration of the locking collar 10 includes four corners
and each corner can receive a projection 16. Other shapes can
be used to allow the projections to enter and then be rotated
to a trapped or locked position.
As shown in Figure 3, the upper post 4 is inserted into the
twist lock arrangement 8 such that the projection 16 is
aligned with a corner of the locking collar 12 of the twist
lock arrangement 8. A cross sectional view of this
arrangement is shown in Figure 5a. The corner 24 of the
locking collar 12 can be considered a receiving slot as it
allows the receipt of the projection 16 within the twist lock
arrangement 8. Inserting the upper scaffold post 4 into the
twist lock arrangement 8 in this manner aligns the projection
16 with the locking slot 14. As shown in Figure 4 a rotation
through approximately 45 degrees restricts the locking
projection within the locking slot. A cross section of this
locking collar is shown in Figure 5b and a cross section of
the projections restricted within the locking slot is shown in
Figure 5c. This provides a simple locking connection of the
upper scaffold post 4 to the lower scaffold post 6. It also
provides a simple visual indication to safety inspectors that
the scaffold posts are locked together safely.
In addition to this locking mechanism the twist lock
arrangement 8 is adapted to receive the traditional spigot
type connection. The twist lock arrangement 8 contains holes
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18 in the connecting sleeve 10. Corresponding holes 20 are
also made through the bottom portion of the post (shown in
upper post 4 in figure 2) for securement when in the locked
position, holes 20 align with holes 18 such that the upper
post 4 can be securely fixed to the lower post 6 using a
pigtail pin 26, rivet, bolt or other known method of fixation.
This fixation acts as an additional fixation to strengthen the
joint in the vertical member over and above that provided by
the projections 16 and maintains projections as in the locking
slot 14.
This design allows a vertical scaffold member fitted with the
twist-lock sleeve to be interchangeable with scaffold vertical
members that do not have a twist-lock projection and have male
spigots at the top of the vertical members. When a vertical
without a twist-lock projection is inserted into the twist
lock arrangement, the upper post is securely attached through
the connecting sleeve 10 to the lower twist lock post with a
pigtail pin, rivet, bolt or other known method of fixation.
The twist lock arrangement including the projections 16 are to
avoid conflict with the normal function of the scaffold post.
The twist lock collar is above the connecting sleeve and above
the lower edge of the upper post. The projections are on the
outside of the scaffold post and the lower portion remains
clear to allow traditional connections to be used. The twist
lock arrangement can include multiple locking slots 14 and
receiving slots 24. In most cases only two projections 16 are
provided on the post.
In a preferred aspect of the invention, four receiving slots
24 and two locking slots 14 are used. This allows for a
series of orientations in which the upper post may be inserted
into the twist lock arrangement 8. In this embodiment, the
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sleeve has one or more holes 18 in the lower part of the
sleeve. These holes accommodate the use of a locking pin, or
pigtail pin 26 which passes through the twist-lock coupling
sleeve and corresponding holes 20 at the bottom of the upper
post 4. This forms a positive lock of the upper post 4 to the
lower post 6 in cases where the upper post is not fitted with
a locking projection, or where the connection between the
vertical members is required, for example to meet specific
safety regulations.
The twist lock arrangement can include multiple locking slots
14 and receiving slots 24 although only two projections are
preferred. For example, four receiving slots 24 and four
locking slots 14 are provided. This allows for a series of
orientations in which the upper post may be inserted into the
twist lock arrangement 8. In this embodiment, the sleeve has
one or more holes 18 in the lower part of the sleeve. These
holes accommodate the use of a rivet, or pigtail pin 26 which
passes through the twist-lock coupling sleeve and
corresponding holes 20 at the bottom of the upper post 4. This
forms a positive lock of the upper post 4 to the lower post 6
in cases where the upper post is not fitted with a locking
projection, or where the connection between the vertical
members is required to resist an axial tensile force that is
beyond the capacity of the locking projections.
In an alternative embodiment, as seen in figure 8, the top
part of the locking sleeve is circular in profile and includes
one or more `L' shaped slots 30. The vertical leg 32 of the
slot is open at its upper end. In this embodiment, when the
upper post is inserted into the sleeve 34, the locking
projection (similar to that shown in figures 1 to 4) on the
upper post passes down the vertical leg 32 of the `L'-shaped
slot 30. When the upper post reaches the top of the lower post
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36, the upper post (not shown) can then be rotated
approximately 45 degrees to restrict the locking projection
within the horizontal leg 38 of the `L' shaped locking slot.
The use of the sleeve to provide the necessary strength for
scaffold leg end to end connection in combination with the
twist lock collar allows new twist lock legs to receive new or
old scaffold legs. The projections 16 are sufficiently spaced
from the bottom of the leg to be completely independent of an
end to end connection with an old style upper or lower leg.
Old style legs can easily have projections and/or twist lock
collars added if desired. This design is thus compatible as a
new improvement to existing sleeve type scaffold leg
connections.
Although various preferred embodiments of the present
invention 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 spirit of the
invention or the scope of the appended claims.
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