Note: Descriptions are shown in the official language in which they were submitted.
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In resistance welding it is necessary to have welding
circuits which supply the welding current to the workpiece
with reliable conductivity. Fixed connections are the
standard of the industry as they produce the better welds
and use less current.
On the other hand, with fixed connections, the loading
and unloading of workpieces occurs in the same location as
the welding so that the operator must work closely ad~acent
to or in the welding area where the welding occurs and where
the electrodes are forcibly prjected by the machine. This
creates a danger of injury for the operator.
The problem of providing safe loading and unloading
position~ ~or the workman remote from the welding area
while at the same time providing optimum welding circuits for
welding appears to be unsolved in the prior art by the
provision of acceptable means which industry can use commercially.
SUMMARY OF THE PRESENT I~VENTION
The present invention relates to a sliding, current
conducting, workpiece holding, movable table for a resistance
welding machine providing reliable conductivity in the welding
position and a loading-unloading station spaced from the
welding position to eliminate danger of injury to the operator.
The apparatus comprises a base mountable on a resistance welding
machine below the welding head, at least two horizontal slide
rails lying on and over the base and extending laterally
outwardly of the base on at least one side of the base beyond
the welding head; each rail having a bottom portion connected
to the base and an upwardly extending top portion; the top
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portion of each rail comprising opposite flat sides lying on
opposite angles converging upwardly toward one another, a
table over-lying the slide rails; the table having means
forming bottom slide channels partially receiving the top
portions of the slide rails, each slide channel having
opposite flat sides lying on opposite angles converging
upwardly into the table; the angulation of the sides of
the slide rails and the angulation of the sides of the
slide channels being substantially equal to provide a close
interfit therebetween to provide a large area of mutual
contact to facilitate transfer of welding current; the
table being slidable on the rails betwe:çn a welding
position below a welding head and a loading-unloading
position outwardly of a welding head; the slide rails and
the slide channels under the force exerted by the welding
head being jammed in substantially solid electrical contact
due to their mutual angular interface allowing slight
motion toward one another form a slidable to a jammed
condition.
With the foregoing in view, it is an object of the
invention to provide a sliding table for resistance welding
machines so that the welding station may be moved into the
welding position for welding with reliable electrical
conductivity and moved to a remote position for loading and
unloading workpieces to reduce the danger of~accidental
injury to the operator.
It is an object of the invention to provide means for
sliding the table which wedge or jam against one another
under the forces employed in welding to provide a solidly
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connected welding circuit and which release absent the
welding forces allowing the table to slide.
An object of the invention is to provide a base
connectable to a welding machine and rails mounted on the
base having opposite flat sides lying at an angle to
one another and converging upwardly toward one another.
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An object of the invention is to provide a table
having complementary angled slide channels for receiving
rails in close interfitting relationship.
An object of the invention is to utilize the
angularly engaging rails and channels to develop a moveable
relationship between them which is normal to their sliding
motion to allow them to move slightly toward one another
to a wedged or jammed condition under welding forces for
conducting welding current and to allow them to release
absent the welding forces to facilitate sliding the table
on the rails.
An object of the invention is to provide a shield
on and moving with the table to cover exposed portions of
the rails extending beyond the table to protect the rails
from welding spatter, dust, etc., to insure good current
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conducting surfaces.
An object of the invention is to provide a tablb
having one or more welding stations so that when one is
in the welding position, the other is in the loading-unload-
ing position spaced from the welding operation.
These and other objects of the invention will become
apparent by reference to the description of the illustrated
embodiment taken in connection with the accompanying drawing.
DESCRIPTION OF THE DRAWING
Fig. 1 is a front elevational view of a welding
machine equipped with the slide table apparatus of the
invention with the table shown in side elevation and including
a power cylinder for moving the table, controls for operating
the cylinder, shields at both ends of the table with the shield
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at the left broken away to show the cylinder, and showing
two welding stations on the table in solid lines and
illustrating a loading-unloading position in broken lines.
Fig. 2 is an enlarged top front oblique perspective
view of the slide table apparatus seen in Fig. 1, with portions
broken away to show internal structure; and indicating the
welding stations in broken lines.
Fig. 3, is an enlarged cross-sectional view of the
apparatus seen in Fig. 2, taken on the line 3-3 thereof,
showing the engagement of the angularly faced slide rails
and channels; and
Fig. 4, is an end view of a rail and a portion of
the base showing a modification of the mounting of the rail
on the base and showing the base broken away.
DETAILED DESCRIPTION OF THF. ILLUSTRATED EMBODIMENT
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Referring now to the drawing wherein like reference
numerals refer to like and corresponding parts throughout the
several views, the slide table apparatus shown therein
illustrates a preferred embodiment of the invention and
comprises a base 10. A'table 14 surmounts the rails 11 and 12.
The table 14 is equipped with channels 15 and 16 which receive
and interfit with the rails 11 and 12 respectively. An arm
17, 17a extends from the base 10 and terminates in an outer
end 18. A power cylinder 19 is connected between the outer
end 18 of the arm 17 and the table 14. Controls 20 are mounted
on the arm 17 for actuating the cylinder 19 to slide the table 14
on the rails 11 and 12. The rails 11 and 12 are secured to the
base 10 by the hold down bo)lts 21 and 22. The table 14 is
slideably secured to the rails 11 and 12 by the gibs 23 and 24
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which are bolted to the table 14 and engage the under side
of the rails 11 and 12. The rails 11 and 12 extend outwardly
from the base 10 and are cross-tied at their outer ends by
the cross pieces 25 and 26.
A shield is mounted on one end of the table 14 and a
shield 28 is mounted on the other end of the table 14. The
shields 27 and 28 overlie and protect the rails 11 and 12
in their exposed areas when the table 14 is moved. The
rails 11 and 12 preferably are made of square copper bar stock.
V-sockets 30 and 31 are formed in the base 10 and receive
the bottom corner of the rails 11 and 12 respectively, Fig. 3,'
the bottom of the rails also may be flat as shown in Fig. 4
where the rail 12 also has a flat bottom which engages the
flat top on the base lOd. The table 14 is made of copper
and thus the slide channels 15 and 16 and the rails 11 and 12
;~ provide copper to copper electrical contact. A welding
station block 32 and a welding station block 33 are mounted
on the table 14. The rails 11, 12 and the channels 15, 16
may be silver plated.
The base 10 is mounted on the welding platen 34 of
the welding machine 35 below the welding head 36. An
electrode 37 on the welding head 36 engages the workpiece 38
on the welding station block 32, 33 when the automatic welding
cycle is actuated, not shown.
In use, the operator actuates the welding cycle and
the head 36 forces the electrode 37 against the workpiece 38
on the station block 33 and the force applied is transferred
to the table 14 forcing the channels 15 and 16 into jammed
contact with the rails 11 and 12 respectively during the
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application of welding current so that the current is
conducted without reduction or obstruction at the slide
channels 15 and 16 and the rails 11 and 12.
After the workpiece 38 is welded and the welding
cycle terminated, the operator places a workpiece on
station block 32 and actuates the cylinder 19 via the
control 20 to move the table 14 from the solid line position
shown in Fig. 1 to the pOsitiQr. indicated by broken lines.
This locates the station block 33 and welded workpiece
outwardly of the head 36 and locates the station block 32
and new workpiece under the head 36. The operator actuates
the welding cycle and the new workpiece is welded. He then
removes the welded workpiece from the station block 33
and replaces it with a new workpiece. He then actuates the
cylinder 19 to move the table 14 from the position indicated
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by broken lines to the solid line position shown. ~e now
actuates the welding cycle and repeats his performance
as previously described.
To insure and/or provide for transverse sliding
movement of the channels 15 and 16 downwardly on the rails
11 and 12 under the forces exerted by the welding head 36,
the top corner of the rails may be milled off to provide
a small longitudinal cavity 50 and 51 between the table 14
and the rails 11 and 12. 'This eliminates corner-to-corner
contact and allows for more wedge-like engagement and action
between the rails 11 and 12 and the channels 15 and 16.
It will be understood that very small movement is all that
is necessary to effect wedging action and/or a jammed condition
between the rails 11 and 12 and the channels 16 and 16 which
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condition is relieved by the removal of the force exerted
by the welding head 36. Also the table may be moved
manually or as desired.
It will be understood also that the table may be
equipped with a single station block and/or travel toward
and away from the machine as well as travel from side-to-side
relative to the machine as shown and that a bottom electrode
may be employed on the table instead of the station block
shown, singly and in combination, also the slide channels
may be formed by adding parts to the table. The scope of
the invention is limited only by the appended claims.
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