Note: Descriptions are shown in the official language in which they were submitted.
CA 02302324 2000-02-25
WO 99/11967 PCT/CA98/00833
SUPPORT ARM
The present invention relates to a support arm.
Applicant's co-pending Canadian Patent Application No.
2,173,562 filed April 4, 1996 discloses a support arm
having an arm structure that is pivotable about a
horizontal axis between raised and lowered positions.
While this support arm has great utility especially in
welding applications, its capabilities and versatility
are not as great as may be considered desirable.
In the present invention, it has been found
that the capabilities and versatility of the arm can be
greatly extended by providing the arm with a support base
having a pivot axis that is maintained parallel to a
vertical axis as the elevation of the arm structure is
adjusted.
The present invention provides a support arm
comprising a support structure, an arm structure
connected to the support structure through a pivotal
connection for pivoting about a horizontal axis, means
for adjusting the elevation of the arm structure by
pivoting it about the horizontal axis, a support base
connected to the arm structure through a pivotal
connection for pivoting relative to the arm structure
about an axis parallel to said horizontal axis, a support
member connected to the support base through a pivotal
connection for pivoting about a pivot axis parallel to a
vertical axis, and a linkage between the support base and
the support structure maintaining the pivot axis of the
support base parallel to a vertical axis as the elevation
of the arm structure is adjusted.
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WO 99/11967 PCT/CA98/00833
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The support member may support various
auxiliary structures, for example a tool tray, air or
vacuum hoses, welding guns, suction hoses or suction arms
that pivot in a radius about the support base. When the
arm structure is raised or lowered, the vertical pivot
connection remains parallel to the vertical axis and
avoids any tendency for the auxiliary structure to swing
under the influence of gravity to a neutral position
different from that desired.by the operator.
The linkage between the support base and the
support structure may comprise a parallelogram linkage.
The invention is more fully described with
reference to the accompanying drawings, by way of example
only.
Fig. 1 is a bottom plan view of a support arm
in folded configuration.
Fig. 2 is a partial perspective view from
underneath of a portion of the arm showing structure in
accordance with the invention.
Fig. 3 is a side view showing one form of
auxiliary structure mounted on the support arm of Fig. 2.
Referring to the drawings, the elements and
functioning of the arm as seen in Fig. 1 are described in
more detail in applicant's co-pending Canadian Patent
Application No. 2,173,562, which should be referred to
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for further details. Briefly, an arm 10 is mounted on a
vertical support surface such as a wall 11. In the
preferred form, as shown, the arm comprises a support
structure comprising a mounting bracket 12 secured to the
wall, a boom 13 pivotally connected to the bracket 12 at
14 to pivot about a vertical axis, a knuckle 16 pivoted to
the boom 13 at 17, and an auxiliary jib portion 18b
pivoted to the knuckle 16 at 19. The pivots 17 and 19
pivot about parallel vertical axes. The boom 18 further
comprises a main jib section 18c hinged to the auxiliary
portion 18b at a pivot connection 56 for pivoting about a
horizontal axis. A cylinder 59 and a piston 62 working in
the cylinder 59 and connected between the auxiliary
portion 18b and the main section 18c are operable to
rotate the main section 18c about the horizontal axis 56
to adjust the elevation of the main section 18c.
A functional head, for example a welding and
welding control apparatus 66, may be supported on an outer
end of the main section 18c and may be connected to, for
example, a rectangular plate 67 secured to rigid tubes
forming part of the main section 18c. Flexible hoses 68
may interconnect between these tubes and further rigid
tubes constituting the boom 13 to provide a fluid pathway
between the functional head 66 and the rear end of the
boom 13 adjacent the wall structure 11.
As illustrated somewhat schematically in
Figs. 2 and 3, a supporting piece 69 extends trans-
versely and is secured to a lower portion of the main
section 18c adjacent the functional head 66. An arm 71 is
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pivotally connected at each end of the supporting piece 69 for
pivoting about a horizontal axis 72 passing through piece 69.
The upper end of each arm 71 is secured to a cross-piece 73
parallel to piece 69 and rigidly connected to a support base
73a, seen in Fig. 3.
A linkage is provided between the support base 73a
and the auxiliary portion 18b in order to align the support
base 73a parallel to a vertical axis 74 as the elevation of the
main section 18c is adjusted upwardly and downwardly relative
to auxiliary portion 18b.
In the example shown, the linkage comprises a
parallelogram linkage. The linkage comprises a connection
member 76 secured on the upper side of the auxiliary portion
18b and a connection rod 77 extending parallel to main section
18c and connected at each side to the connection member 76
through a pivotal connection allowing pivoting about a
horizontal axis 78. At the opposite end, each connection rod 77
is connected to a respective side of the cross-piece 73 that
supports the support base 73a through a pivotal connection
likewise allowing pivoting between the rod 77 and cross-piece
73 about a horizontal axis 79. A support member, for example a
swivel arm 81, is connected to the support base 73a through a
pivotal connection 82 for pivoting the arm 81 relative to the
base 73a about the vertical axis 74.
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With this arrangement, as the main section 18c rises
and falls relative to the auxiliary portion 18b, the axis 74 is
maintained parallel to the vertical.
Other forms of linkage may be used between the
support base 73a and the auxiliary portion 18b for maintaining
the axis 74 vertical, for example coupled hydraulic cylinders
and the like.
In the example illustrated, an auxiliary structure
comprising a low pressure high volume air extraction arm 83 is
secured to the swivel arm 81. The arm 83 comprises an
extraction head 84 connected to a flexible large diameter hose
86, the hose 86 and head 84 being supported through adjustable
linkage apparatus 87 connected to a base 88 secured to the arm
81. Extraction arms such as arm 83 are in themselves well
known, and are available, for example, Dansk Klimablock A/G,
Denmark, from Lincoln Electric of Cleveland, Ohio, and others.
With the arrangement of the invention, the extraction
head 84 can be positioned by the operator in any desired radial
position relative to the vertical axis 74, regardless of the
angle of inclination of the arm structure 18c, without the arm
83 and head 84 tending to swing under the influence of gravity
to a lower or neutral position. Other auxiliary structures, for
example air or vacuum hoses, welding guns or suction hoses may
likewise be pivoted on arm 81 pivotally connected to the
support base 73.
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Rearwardly of the arm 81, the flexible conduit 86 may
be connected to a service conduit, for example a rigid fluid
conduit 89 supported on support brackets 91 rigidly connected
at their lower ends on the rods 77. Rearwardly, the conduit 89
may be connected through a flexible conduit and rigid conduit
supported on the knuckle 16 and on the boom 13, respectively
