Note: Descriptions are shown in the official language in which they were submitted.
1~)45S14 -
BACKGROUND OF THE INVENTION
The present invention relates to apparatus for
forming wire fabric cages used in reinforcing concrete
pipe. In the manufacture of pipe reinforcing cages,
wire fabric is typically passed through a set of form~
ing rollers which bend it into a cylinder~ Its ends
are then welded together. Such a system is represent-
ed by U.S. Patent No. 3,678,971 issued July 25, 1972
to Alfred A. Nordgren. Also, cages have been manu-
factured by laying out the longitudinal wires for the
pipe cage and holding them in position while circum- ;
scribing them with a spiral wrap wire, welding the
.
junctions to complete the cage. Such a system is dis-
closed in U. S. Patent No. 3,437,114 issued April 8,
1969 to D. P. Whitacre et al.
Both of the above methods are time-consuming.
After cages are formed by bending them through forming
rollers, the ends of the fabric must be welded. Such
welding is typically done manually and automatic weld-
ers for such cages have not been particularly commer-
cially successful.
Both the ~ordgren and Whitacre machines require
readjustment every ~ime on~ wants to manufacture
. . .
different sized cages. Thus, the machine must first
25 be set up for a run of a large number of cages. To ~ -
.. . ~ .
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then do cages of a different size, the machine has to
be reset up fox the new sized cages.
This is inconvenient since cage assemblies are ~
.. :.- . '.
frequently used in which a smaller diameter cage is ;
; 5 positioned inside a larger diameter cage for subsequent -
molding into a concrete pipe. The necessity of doing - -
large runs requires that a number of cages of the same
size be stored at some point on the manufacturing floor -
for later assembly with different sized cages of a sub-
-i 10 sequent run.
, . . ~i~. .... .
SUMMARY OF THE INVENTION
., .
The method and apparatus of the present invention
facilitates the fully automated produation o~ pipe re-
inforcing cages or of any like cylindrical or closed
~i 15 loop object, and even facilitates sequentially manu-
facturing cages of different sizes by simply feedinq
,~ into the system wire abric sections, or work pieces,
of differing lengths.
In the present invention, the ends of the work
piece are gripped by gripping means which are simul-
~! taneously rotated towards one another and advanced `
towards one another whereby the free ends of the work
piece are rolled over inwardly towards one another and
J ~
;~ advanced towards one another to create a closed loop~
`! 25 In a preferred aspect of the invention, synchronism ~
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1~45Sl~
means are provided for synchronizing the rate of rota- ;
tion of the gripping means with a rate of advancement
of the gripping means towards one another.
Other preferred aspects include the provision ~
5 of a welding means located approximately at the point ;
where the two gripping means bring the ends of the work
piece together. A unique line upset welding method is ,~
employed in accordance with the present invention to
facilitate a sound weld and indeed, 100% line upset
welding is facilitated whereby the ends of the pipe
reinforcing cage or the like are squared rather than
skewed. To feed different sized work pieces into the
apparatus, a unique infeed carriage assembly is employ-
ed.
In accordance with a specific embodiment, appara-
tus for advAncing a workpiece comprise: a supporting
structure including guide means extending therealong~
carriage means guidably supported by said guide means
and including drive means for moving said carriage ~;
along said guide means; and clamping means including
first and second elements for selectively clamping a ;
.
; workpiece therebetween, said clamping means coupled to
said carriage assembly for movement therewith and where- ~ ;
in said first and second elements include movable means
engaging a wor~piece held therebetween for moving said
workpiece with respect to said clamping means.
"
,
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,! These and other advantages, features and objects
of the present invention will be more fully understood
and appreciated by reference to the written spec.ifica- :
tion and appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS ...
FIG. lA is a front elevational view of the left end
of apparatus embodying the present invention;
FIG. lB is a front elevational view of the middle
section of apparatus embodying the present invention and~. ~
10 is contiguous with FIGS. lA and lC; ~ ~ :
FIG. lC is a front elevational view of the right end
of apparatus embodying the present invention;
FIG. 2A is a top plan view of the left end of appara- :
tus embodying the present invention;
FIG. 2B is a top plan view of the middle section of ~ -:
: apparatus embodying the present invention and is contigu-
ous with FIGS. 2A and 2C; ;
FIG. 2C is a top plan view of the right end of
apparatus embodying the present invention; :
FIG. 3 is a right end elevational view partly
broken away of the apparatus embodying the present ~
invention; - ..
FIGo 4 is an enlarged detailed front elevational
view partly broken away and partly in cross section of
25 the infeed means shown in FIGS. lA and 2A; ~;~
: 5
.. . . -:.
~04SS~4
FIG. 5 is a ragmentary left end elevational view
of the apparatus shown in FIG. 4
FIG. 6 is a top plan view of the infeed means shown .
in FIG. 4 and further showing the movable support bed
5 associated therewith; ~ :
FIG. 7 is an enlarged front elevational view partly ~;;
in cross section of one of the gripper assemblies shown
in FIGS. 1 and 2 showing the combing means associated
therewith in detail;
FIG. 8 is a fragmentary right end elevational view
of the combing means shown in FIG. 7; ~ :
FIG. 9 is a schematic view of the yrippex assembly : : :
slide and carriage; .;
FIG. 10 is a cross section o~ the gripper assembly .
slide and carriage taken along section lines X-X in
FIG. 11;
,~ FIG. 11 is a fragmentary front perspective view
: ~~ partly broken away of one of the gripper assemblies; -
FIG. 12 is a fragmentary front elevational view
of the apparatus of the present invention shown during
one portion of a cycle of operation;
.
FIG. 13 is a fragmentary front elevational view .
: of the apparatus o~ the present invention shown auring
. --~
a successive portion o~:a cycle of operation;
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FIGS. 14A and 14B are fragmentary front eleva- :.
tional views of the apparatus of the present invention . :
shown during a successive portion of a cycle of opera-
tion;
FIG. 15 is an enlarged fragmentary front eleva-
tional view of the apparatus of the present invention
shown during a successive portion of a cycle of opera-
tion;
FIG. 16 is a fragmentary front elevational view of
.
10 one of the gripper assemblies; .
FIG. 17 is an enlarged fragmentary perspective view .~
partly broken away of the welding apparatus o~ the pre- :
sent invention;
FIG. 18A is a ragmentary perspective view of the ;; ~. .
overlapped juxtaposed circumferential wires prior to
welding;
FIG. 18B is an enlarged fragmentary view of the . ::
..
: . electrode jaws of the welding apparatus showing the
. -. ...
relative position of a pair of wires to be welded;
FIG. l9A is a ragmentary perspective view o the .
welded wire junction; . :
- . : ,
FIG. l9B is an enlarged fragmentary view o the ~. ::.
jaws of the welding apparatus after the welding has
,
: been completed;
~: 25
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FIG. 20 is an enlarged right end elevational view
of the apparatus of the present invention showing the
outfeed means;
FIG. 21 is a block diagram of the control system
of the present invention; and
FIG. 22 is an enlarged cross section of one of the
lower jaw members.
DETAILED DESCRIPTIO~ OF THE
PREFERRED EMBODIMEMT
Before discussing the structural details of the ~ ~
':"
apparatus embodying the present invention, a brief
description of the principal elements of the rnachine
together with their function is presented here. The
machine receives a precut section of wire fabric 10 at
15 the left end as seen in FIGS. 1 and 2. Fabric 10 in- -
cludes longitudinally extending parallel wires 12 which
; when the cage is formed, define the circumferential
wires of the reinforcing cage. Extending transversely
to the circumferential wires 12 are transverse wires 14
which become the longitudinally extending wires of the
formed cylindrical cage. The precut section 10 of wire
fabric is received from a shear machine (not shown) which
draws fabric from a roll supply of such fabric, cuts the
fabric to a desired length which corresponds to the cir-
`, 25 cumference of a cage to be formed, slightly bends the
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free ends of the circumferential wires 12 extending
from the adjacent transverse wire and introduces the
precut section 10 into the cage forming machine infeed
means 20 shown at the left end of FIGS. 1 and 2. - ~ .
Means 20 includes a movable carriage 100 (FIG~ 4) :
and clamping means 140 which are in an open position to .
receive the wire section and which can be closed to
clamp the wire section therebetween for transporting the . .
fabric section to the right in the direction indicated
by arrow A in FIGS. 1 and 2 for introducing the fabric
section to awaiting gripping members tFIG. 13). The ~.:
clamping means of the carriage include movable belts ~;
which can be intermittently driven -for forcing the fabric :::
section from the carriage means and into the awaiting
gripping members. Once this is accomplished, the clamp~
- ing means open and the carriage returns to its le:Etmost
position shown in FIGS. l and 20 . .
The gripping means comprises a left gripping assem- .
bly 30 and a right gripping assembly 40 movable toward
20 the middle of the machine when forminy a wire cage (FIG. -
15) and receiving a new section of wire and to an outer-
most position, best seen in FIGS, 1 and 2, where they
grip the fabric section near the ends and are in prepara-
tion of advancing toward one another. Each of the
gripping assemblies includes a pair of gripping jaws
,
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240 and 250 (FIG. 11) for holding the ~abric. The
gripping jaws are mounted between rotatable mounting
plates 24~ and 276 such that as the gripping members
are advanced toward the center of the machine to bring
the free ends of the fabric section 1:ogether, the fabric
ends are rotated in synchronism to form the circular
cross section cage. The gripping jaw plates are coupled
to slides 280 which are coupled in turn to carriages 280'
for advancing the gripping jaws toward and away from
each other~ The slides are coupled to the carriages by
biasing means and include inertial detection means for
controlling the speed of advancement of the carriages
to be in synchronism with the jaw rotation for assu~ing
that a perfect cylindrical cage is formed.
As seen in FIGS. 1 and particularly 1~, a plurality
of different sized pipe reinforcing cages 12a-12e can be
manufactured with *he largest diameter belng shown in
FIGS. 1 and 2 corresponding in circumference to the dis-
tance between the outermost position of the gripping
2Q assemblies. It is to be understood that any diameter
.
cage, intermediate to those shown, can be manufactured ~-
equally as well.
~ .
A welding assembly 50 is supported above the machine ~ ~
.
and movable transversely across the formed fabric cage
-: ~ : ::
25 in a direction indicated by arrow C in FIG. 2 and includes ~ - ~
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a plurality of welding heads which clamp the mating ends
of the fabric section held in place by the gripping mem-
bers for providing a 100% upset weld to each of the cir-
, ~. . .
cumferential wires forming the cage. Once the welding
operation is completed, the gripping jaws are opened
permitting the formed fabric cage to be dispatched from
- the machine by means of a take-away conveyor 60 (FIG. ~ ~
20) which is mounted on a vertical adjustment means for ;
accommodating different diameter cages.
' 10 Having very briefly described the principal elements
of the present invention, a detailed description of each
of the elements will be presented herein followed by a
description of a cycle of operation.
I MACHINE FRAME
; ~ ~ 15 As best seen ln FIGS. lA-lC and 2A-2C, the infeed
I means, gripper assemblies, and the welding assembly are
each movably mounted on guide rails of a stationary ;;
, ramework of the machlne. The framework comprises a ,
, ~.
plurality of vertical stanchions 70 extending between
' 20 the floor 72 of an installation and the bed of a rec-
¦ tangular framework comprising lower longitudinal support -
~; members 74, upper longitudinal support members 76, lower
cross supports 73 at opposite ends of the machine, and `~
upper cross supports 75. The lower rectangular frame ~ -
i~ 25 is coupled to the upper rectangular frame by means of ~ ~ -
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vertical posts 77 and cross braces 78. Posts 77 are
preferably located in line with stanchions 70. Rein-
forcing braces 79 are positioned to support the junc-
tions between the vertical stanchions and the frame
5 members. In the preferred embodiment: as seen in FIG. `
lB, the take-away conveyor 60 can be mounted in a pit
80 in the floor of the installation such that the machin-
ery height is not excessive or handling the largest ;~
:~:
diameter pipe cage.
Extending significantly the entire length of the
: ; .
framework on opposite sides thereof is a pair of guide
rails 82,84 which support both the gripping assemblies
30 and 40 for motion therealong as well as the infeed
means 20. Positioned below g~ide rails 82 and 84 lS a ~;
second pair of rails 86 and 88 (FIGS. lA-lC and 4 and -
5) which, as best seen in FIG. 4, comprises a gear rack
having a plurality of teeth 89 formed in the lower sur-
faces thereof. Racks 86 and 88 serve to provide inter-
'..' :: ,
coupling of the drive means for the infeed carriage and
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gripping assemblies as described in detail below.
INFEED MEA~S
It is noted here that one of the circumferential
.~, .
wires 12 is utilized as a tracking wire identified in
FIG. 2 as wire 12'. As the incoming section of wire
fabric enters the forming machine, the tracking wire 12'
' ::
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is spanned by a pair of star wheels 90 and 92 rotatably
mounted to axle 94 by means of bearings 95 and 96, which
axle in turn is mounted to bracket 79 as best seen in
FIGS. lA and 6. The star wheels include a plurality of
rounded, star-like projecting teeth 97 which define
notches therebetween which engage the transvexse wires
14 as the wire section is advanced to the input end of
the forming machine. Thus, the star wheels, which are
, , vertically positioned to lie in the plane of travel of
; 10 the wire fabric, assure the longitudinal alignment of
the fabric as it enters the forming machine by spanning
the tracking wire 12 t and prevent skewing of the fabric.
It is noted here that in the drawings, arrow A in-
dicates motion from left to right in the machine as shown
in FIGS. 1 and 2 and is seen in the end view either as an
encircled dot indicating the arrow is coming out of the
plane of the drawing or a circle with cross hairs indicat-
ing the arrow is moving into the plane of the drawing.
The infeed means 20 shown in FIG. lA is used to provide
gross motion of the web fabric from the input end of the
forming machine to the center section whereupon an incre~
.
mental transferring motion is imparted to the fabric to
feed it to the awaiting gripping members. The infeed
means is now described in detail with reference to FIGS. ~- ;
lA, 2A and 4-6.
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The infeed means 20 comprises a carriage assembly
; 100 movably supported between guide rails 82 and 84.
~ Carriage 100 comprises a pair of tubular support members; 102 and 104 extending between upstanding end brackets 104
and 106 at opposite ends thereof. Cross braces 103 (FIG.
6) extend between members 102 and 104. Braces 105 rein- :
force these junctions at opposite ends. Extending from
the outer face of each of the end brackets 104 and 106
are horizontally spaced pairs of vertically spaced guide .- :
10 rollers 108 which span the upper and lower surfaces oi ~ ~
guide rail 82 and rollers 110 associated with bracket 106 ~: :
which span the upper and lower surfaces of guide rail 84. ::
A pair o~ horizontally oriented guide wheels 112 are
: .
, coupled to end bracket 104 as seen in FIGS. 5 and 6 and : ; : : .
similar wheels 114 are rotatably coupled to end bracket
;.~. :
106 and extend through slots therein such that carriage . ~ .
~ 100 captures three sides of each of the guide rails 82
I and 84 to provide guided movement of the carriage along .;
the guide rails with minimum ~riction and play.
A hydraulic carriage drive motor 116 is coupled be- .
tween me~bers 102 and 104 and is coupled to a gear reduc- --
ing unit 118. The output shaft of unit 118 drives a first : ;
. drive gear 120 associated with rack 88. A second drive
gear 122 associated with rack 86 is driven through a drive
shaft 125 coupled to gear box 118 and to gear box 119 : .
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associated with drive gear 122. Drive shaft 125 extends
through sleeve bushings 126 and 127 mounted in downwardly
depending support arms 128 and 130, respectively, of the
carriage.
Arms 128 and 130 extend downwardly from arms 102 and
104 of carriage lO0 to the movable clamping means 140.
A cross member 129 (FIG. 5) extends between support arms
128 and 130. Means 140 consists o~ a lower platform 150 -
(i.e., first element) which is stationary with respect to
arms 128 and 130 and an upper platform 160 (i.e., second
.. ;:
element) vertically movable as indicated by arrow B in ~
......... .
FIG. 4 to alternately engage and disengage platform 150
to clamp and unclamp the wire ~abric 10 between the upper
and lower movable platforms.
The lower platform 150 comprises forward and rearward
.
end rollers 152 and 154, respectively, (FIGS. 5 and 6)
which are horizontally spaced and rotatably mounted to
the ends of end brackets 151 and 152 in turn coupled to
arms 130 and 128, respectively. Bearings rotatably mount
these rollers to the forward and rearward portions of the
end brackets. Extending over and between rollers 152 and
154 is a relatively wide endless loop support belt 155
forming a movable support bed for the undersurface of wire
fabric lO. Roller 154 is mounked on an axle 156 which is
coupled to a hydraulic drive motor 157 (FIG. 5) at one end
' '
15.
. .
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and includes a chain sprocket 158 at the opposite end.
Roller 152 is mounted to axle 153 and includes a sprocket
159 which aligns and is coupled with sprocket 158 by means
of an interconnecting drive chain 158' (FIG. 6). Thus, ~ ;
: '.' ~ :'
drive belt 155 and both rollers 152 and 154 are driven by
a single hydraulic drive motor 157. Drive motor 157 is -
, - controllably actuated to rotate belt 155 about rollers 152
and 154 to move the wire mesh 10 in a direction indicated
by arrow A from the infeed means 20 as described below.
The upper movable clamping platform 160 comprises a -
pair of spaced forward roller members 162 and 164 and a
pair of rearward roller members 166 and 168. Rollers 162
:
and 166 are rotatably coupled between brackets 161 and
163 by means of suitable axle and bearing means while
rollers 164 and 168 are similarly mounted between end
~ - :: :.
, brackets 165 and 167.
...:. ,
~ A drive shaft 170 (FIG. 5) is coupled to rollers 166
'
¦ and 168 and to drive motor 172 or rotatably driving
l rollers 166 and 168. Shaft 170 extends from an end of
;~ 20 roller 168 remote from motor 172 terminating in a sprocket
..... .. .
.. ..
~i 174. A chain 175 (FIG. 6) engages a similar sprocket 176
mounted on shaft 173 extending through rollers 162 an~
~ 164 such that the single drive motor 172 actuates each
-I of thé four rollers associated with the upper platform.
~ ~ 25 An endless loop belt 177 extends between rollers 162, 166
,~ while endless loop belt 178 extends between rollers 164,
'' ,
; 16.
,1 .
04~;51~ ;
168. Motor 172 is intermittently driven to rotate belts
177 and 178 in a direction opposite the lower platform
belt 155 such that when the upper platform is in its
clamping position, the wire fabric is driven through the
infeed means in the same direction by the upper and lower
movable clamping members. ~ -
In order to raise and lower the upper movable plat-
form 160 between an unclamping and clamping posit:ion,
respectively, a pair of brackets 180 and 182 extend be-
tween end brackets 161 and 163 and 165 and 167 respec-
tively (FIG. 6). A pair of pivot arms 181 and 183 are
each pivotally coupled at their lower ends to brackets
180 and 182, respectively, by means of a yoke interconnec- ;;
tion 185 (FIG. 5). These arms are pivotally coupled at
their upper ends to cross member 129 by means of a simi-
lar pivot connection 187. Such construction permits the -
pivotal movement of the upper movable platform 160 with
respect to the lower movable platorm 150. In order to
raise and lower the upper movable platform, a cylinder
190 is pivotally coupled at its upper end to cross mem-
.~ . . ~, .
; ber 104 as best seen in PIG. 4 and has a shat 191 which
is pivotally coupled to arm 181 by pivot connection 192
(~IG.- 5). Cyllnder l90 is selectively actuated to lower
or raise the upper movable platform 160 for clamping and
unclamping the wire fabric between the endless loop belts.
:: ~ .
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As the infeed means 20 moves from left to right
as illustrated in FIGS. 12 and 13, a movable e~pand- ;
: . -
able support bed 200, coupled to the carriage, providessupport for the trailing portion of the wire fabric.
The construction of the movable support bed 200 is now
presented with reference to FIGS. 4-6 and 12-14A.
The expandable traveling bed support structure
comprises four channel-shaped cross members 202, 204,
206 and 208 which extend between end plates 210 at
opposite ends of each of the cross members. Mounted to
. ~,:, . .:
the vertical support stanchion 70 and extendlng longi-
tudinally therealong on the inner side thereof on each ;
side o the forming machine is a guide rail 212. Each
of the end plates 210 includes upper and lower pairs of -
cam followers rotatably mounted to the end plates 210
. . .
for spanning each of the guide rails 212 in much the ;~
same fashion as the carriage 100 is mounted to guide ;
rails 82 and 84. Thus, each of the cross members 202,
.. ~ . .
204, 206 and 208 is rollably supported along and between
guide rails 212. Positioned on the upper surfaces of
each cross member is a pair 214 of freewheeling conveyor
rollers mounted thereto by conventional mounting brackets
including bearings. The upper portion of the rollers 214
lie in the plane of travel of the wire fabric. -
......
18.
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Four chains 220, 222, 224 and 226 are extended be-
tween pairs of associated sprockets 230, 232, 234 and
236, respectively, as best seen in FIGS. 5 and 13. Each
set of the horizontally spaced sprockets is mounted and
keyed to a rotatable axle 221 extencling from brackets
225 at the left end and near the center of the forming
machine. The sprockets are of progressively different
diameters such that for a given motion of the outermost
chain, the chains associated with the smaller sprockets ~ ~;
will move a greater distance. Channel-shaped member 208
includes a clamping member 209 extending from its lower
surface and coupling channel 208 to chain 222 which is
~1 :
the chain associated with the second largest diameter
sprocket 232. Similarly, each cross member is coupled
to an associated chain. Thus, member 204 is coupled to
chain 226 via clamp 205 and member 206 is coupled to
chain 224 via clamp 207 (FIG. 13).
Member 202 is coupled to the base of the machine
via clamp 203 and i5 stationary. Chain ?20 is further
coupled to the carriage arm 128 by means of a bracket
211 (FIG. 5) such that as carriage 100 is progressively
advanced toward the middle of the cage forming machine, ~
the freewheeling rollers 214 mounted on the associated ~;
'., '',:.
cross members are progressively advanced to expand in a
uniformly, progressively spaced fashion to provide
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continuous support for the wire fabric as it is advanced
to the middle section of the machine. Such construction,
therefore, provides an expandable traveling support bed
for the infeed means which provides continuous rolling
support for the wire fabric and which expands and
collapses as the carriage extends to advance to a fabric
transferring position and retracts to receive a successive
sheet of precut fabric.
GRIPPING ASSEMBI,IES
10Initially, it is noted that the gripping assemblies
30 and 40 are substantially identical with the exception
that jaw assembly 30 includes a movable guide ramp 282
for guiding the leading end of wire fabric through the
jaw assembly as it is transferred from the infeed means
20. Each of the gripper assemblies includes a pair of
jaws, one of which is movable with respect to the other
for opening and closing the jaws for alternate}y receiv- ;
ing and gripping the wire fabric. Both such jaws are
rotatably mounted to a slide in turn slidably mounted to
a carriage for motion along the guide rails of the form-
ing machine. Each gripper assembly further includes
combing means which can be retracted between inoperative
` and operative positions~ which combing means are coupled
to th~ slide and selectively actuated for combing the
protruding free ends of the circumferential wires to
.."":
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assure their alignment with mating ends of correspond- ;
ing circumferential wires as the cylindrical cage is
formed. The comb means includes means for detecting ;~.
the end of the wire fabric for controlling the advance-
- 5 ment of the fabric into the gripping assembly and the
subsequent combing operation. Having briefly described
the common elements of each of the gripper assemblies,
a detailed description of the gripper assemblies is : .
presented in conjunction with FIGS. 7-11 and 16. . :
Each of the gripper assemblies includes a lower
, gripping jaw 240 which comprises a bar having a flat
upper surface 242 which extends continuously between
jaw end plates 244 and 246. The lower gripping jaw
. is bolted to the rectangular support channel 248, also : :;
welded between end plates 244 and 246. Each of the : :;
gripper assemblies also includes an upper gripping jaw . -
' 250 comprising an elongated bar having a gripping sur- :
face 252 facing the gripping surface 242 of lower jaw
:: .
240 and spaced slightly therefrom when in a closed
position to accommodate the thickness of the wire fab~
ric. As seen in FIG. 22, lower jaw 240 includes an `~
, elongated blade 241 fitted in an elongated slot in an
elongated support bar 243. Blade 241 includes a plural- : .
ity of oversized apertures 241' extending along the :.-.
. .
blade and through which extends a plurality of capture
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55~L4
pins 243'. This mounting arrangement permits blade 241
to move in and out of member 243 in a limited fashion. `
Backing blade 241 on a surface opposite wire engaging
surface 242 is a plurality of spaced pistons 245' mount-
ed in spaced cylinder 246' formed in member 243. An o-
ring seal 247' seals each of the pistons and associated
cylinder walls. An elongated aperture 248 communicates
with the lower end of each of the pistons and serves as
a manifold to supply hydraulic fluid to force the pis-
tons against blade 241 and apply a predetermined pres-
sure against the wire fabric. This permits some com-
pensating motion for the gripping jaws to accommodate
any unevenness along the width of the fabric while
stiIl securely holding it in place.
- 15 Upper jaw 250 is pivotally mounted with respect to
the lower jaw by a support member 248 and pivot mounting
:
bracket 249 including a pivot pin 251 extending between ;
an aperture in bracket 249 and an aperture formed in one
end of the jaws 250. The opposite end of upper jaw 250
.:~
is rDunded and includes a relatively large roller 254
; mounted thereon for engagement by a hook-shaped jaw
latch 256 which is pivotally mounted to a bracket 257 ~`
,: : ;: .
'~ ~ by means of pivot pin 258. The end of latch 256 remote
Erom the concavely curved latching portion 255 is pivot-
ally coupled to a latch cylinder 260 by means of a pivot
,
~ ~ connection 262 coupling the end of the latch to cylinder
`' .
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22.
~55~
shaft 264. The remote end of latch cylinder 260 is
pivotally coupled to support member 248 at pivot connec-
tion 265.
The pivot end of jaw 250 in:cludles a bell crank 266 ~
5 coupled to the upper jaw at its pivot connection and :. :
pivotally coupled at its remote end to shaft 268 o~ upper ~ : :
jaw actuating cylinder 270. The end of cylinder 270 re-
mote from pivot connection 267 with crank arm 266 includes . :
a pivotal coupling 272 to support member 248. Thus, by
actuation of cylinders 260 and 270, upper jaw 250 can be -
opened for removal of a wire cage therefrom as shown in
FIG. 20 (in which the upper jaw has been rotat:ed to a
. : .
lower position) or closed and locked in position by latch
256 for securely holding the ends of the wire fabric dur~
ing the forming and welding steps.
Jaw end plates 244 and 246 include stub axles 245 ~ .
and 247, respectively, extending outwardly therefrom and .
through downwardly depending end plates 274 and 276 of ~
slide 280. A commercially available rotary actuator 275 : : :
is coupled to shaft 245 (FIG. 11) and is mounted to end
. plate 274 and is actuated for rotating the upper and low- ~
:: : er:jaw members during the forming operation as described ~:
in detail below. Stub shaft 245 includes a splined con-
~ nection with rotary actuator 225 permitting axial motion ~;
: 25 of the upper and lower jaws in a direction indicated by
.:
':
-
: , ': '
"','',,': ~
:. ~:...:
~455~4 :
arrow C in FIG. 11. Stub shaft 247 extends into andcommunicates with a rotating cylinder 253 mounted to
end plate 276 and actuatable for providing incremental
..
motion as indicated by arrow C which is utilized to
shift one end of the wire fabric wit:h respect to the
stationary remaining end of the wire fabric. As will be
described in greater detail below, as the wire cage is ~ ~ -
made, the extending circumferential wire ends are ini-
tially skewed with respect to each other so that as the
cylindrical cage is made, the wire ends will not inter~
ere with each other. Once the cylinder is formed, how- ~-
~ :.:~: .
ever, it i9 desired to make 100% upset weld thus necessi- :;
tating the axial shifting o one o the ends o the wire
. . ..
fabric such that the ree ends o the circumferential ~`
wire will be aligned~with and in contact (i.e., abutted)
,: . . !'. ., ~, .
l, with each other. This is achieved by actuating cylinder ~
,:
Jl~ ~ 253 which engages stub shaft 247 for shifting the jaws
~ of gripper assembly 40 an incremental distance.
,
~ Before describing the slide and carriage construc- ~
~ . .
¦~ 20 tion for each o the gripper assemblies, a description
o the movable guide ramp or assembly 40 is presented
followed by a description of the combing mechanism or - -~
straightening~the free ends of the circumferential wires. ; ~ -
As noted above, the guide ramp assembly is required only
,
25 in the left end gripping assembly 30 through which the ~ ;
leading end'o wire fabric advanced into the forming
: : , .
J~ machine.
l 24.
~i ;: ,.
~045514 -
The lower jaw member 240 includes at least three
notches which accommodate movable guide arms 282 as best
seen in FIG. 7. Each ramp arm 282 includes a tapered
leading edge 283 which when the arm 282 is pivoted to
5 its raised position (shown in phantom form in FIG. 7), :-
engages a transverse wire of the incoming wire fabric :-~
to guide the fabric between the open gripper jaws. Arm
.
282 is pivotally coupled to the upper plate 284 of sup- : :
port member 248 by means of pivot coupling 285. Each : :
arm is coupled to an actuating cylinder 286 mounted with-
in support box 248 by means of a pivotal coupling 287
mounted to the inner surface of floor 288 of box 248. A
slot 289 is provided in the forward wall 290 of box 248 ; ;
permitting cylinder shaft 292 to extend therefrom and be
pivotally coupled to arm 282 by means of pivot connection
295. In FIG. 7, the ramp is shown in its normally lower- -
ed position in solid lines and is shown in phantom form ;
in its momentarily raised position upon actuation of cy-
linder 286 prior to the transfer of wire fabric into the
gripping assemblies from infeed means 20. Once the wire
fabric has advanced through gripper assembly 30 and into
: gripper assembly 40 (which does not require a guide r~amp .
since the wire fabric is entering in an opposite direc-
tioa as showa in the gripper assembly 30~of FIGo 7) and . . ~:
: 25 is detected by gripper assembly 40, ~he guide arms 282
are lowered by the deactuation of cylinders 286 associat- ':
:
ed therewith.
: 25.
.. .. . . . . . .. .. .. . . .... . . .. . . . ...
~455~
Each of the gripper assemblies 30 and 40 includes
~ a comb assembly 300 which can be pivoted and raised out
; of the way of the gripping jaws during the forming opera-
; .
tion as seen in FIG. 12 and which are lowered to provide
the combing of the free ends of the circumferential wires
as well as providing a reference for controlling the posi- ;
'~
tion of the fabric in the gripping assemblies. While the ;~
combing assemblies are substantially identical, their
operation with respect to the wire cages are different.
A description of the detai}ed functioning of the comb
assemblies will be deferred until the subsection OPERATION
below. A detailed description of the construction of each
of the comb assemblies, however, is now presented with
reference to FIGS. 7, 8 and 11.
- Each of the comb assemblies 300 includes a plurality ~ -
', of spaced comb supporting arms 302 rigidly secured to a
. .
shaft 304 which is pivotally mounted between slide end
plates 274 and 276. Pivotally mounted on shaft 304 to
provide relative motion between itself and arm 302 is a
20 plurality of spaced drive arms 306. Arms 302 and 306
are biased in a spread position by means of at least a
,
pair of spaced~spring block couplings 310 including a
,
~;~ coupling rod 312 (FIG. 7) circumscribed by a compression
spring 314 extending between pivotable mounting blocXs
- .,: ., . ~
25 316. Cross support 334' extends between arms 306. ~
~. . . .
~: :".-. :
,.
":
26.
~0~5514 ~: :
Shaft 312 is permitted to extend through one of the
mounting blocks 316 such that when arm 306 is moved
toward arm 302, shaft 312 can extencl therethrough.
Arms 302 and 306 are simultaneously moved by a rotary -.
drive 320 mounted to the end of shaft 304 on the side
opposite end support 276 and shown i.n phantom form in
FIG. 11. Thus, each of the comb assemblies 300 can be
rotated in an out of the way position by actuation of
rotary drive 320 to rotate the assembly in a direction
indicated by arrow D in FIG. 7 during the forming opera-
tion. ~;
When in its lowered and operative position as shown
in FIG. 7, however, arm 302 is substantially vertically
extending such that a multiple tooth comb plate 325 hav- ; :
ing a plurality of teeth 326 formed along the lower edge
can be lowered to engage the circumferential wires. Comb
~ .
: plate 325 is mounted to a backing plate 328 which is
j; slidably supported at opposite ends for vertical motion
about vertically extending shafts 329 by means of sleeves :
330. Shafts 329 are supported on arms 302 rotatably
coupled at the upper end to shaft 304 by means of sleeve
334. Arms 306 extend upwardly and are secured to shaft ` :
304 by means of sleeve 339 keyed to the shaft. :
The comb 325 is raised and lowered by means of a --
pair of comb cylinders 340 positioned at opposite ends
'''" ';"
..
", ~
27. -~-
: ' ': '
~ ~ .
10455~4 ;` ; ~
of the comb plate 328 and including rods 342 pivotally
coupled to the comb plate 328 by means of a pivotal
joint 344. The end of each cylinder 340 remote from -
,. . ..
shaft 342 is pivotally coupled to a bracket 341 by means
of pivot connection 343. Bracket 341 in turn is secured
to arm 302. A sleeve 346 surrounds a journal 348 and
serves as a torque shaft for two pivot rods 350 spaced ;
at two extremes of comb support plate 328 to assure uni-
form raising and lowering of comb 325. Each of the pivot `
rods 350 is pivotally coupled at an upper end to sleeve
346 by pivot coupling 352 and at a lower end to the comb -
plate 328 by pivot coupling 354.
It is noted here that the comb teeth 326 shown in
FIG. 8 are selected to converge at an angle of approxi-- -`~
mately 60 and have sufficient depth such that they en-
gage standard mesh wire fabric and straighten circumfer-
ential wires as described below even though the circum-
~: ~
ferentially extending free ends are relatively bent ~;
initially. As the wire mesh varies significantly with
different wire fabrics, it may be required that the comb
:' . :;plate 325 be changed. To facilitate changing the plate,
~; ~ a plurality of bolts 327 and dowels 327a ara employed to -
secure the comb plate to the backing support plate 328.
To assure reproducible and proper registration of the
wire fabric with respect to the gripping jaws during the
~; ' ' .
,
28.
'
~L04~5~
combing operation, each end of the comb 325 includes a
stop 333 which engages a projecting stop 337 (FIG. 7)
associated with the lower jaw 240 of the gripping assem-
bly to assure correct registration during the combing
operation.
The support arms 302 include a two-position stop
360 comprising a step cut block 36~ coupled to a carriage
364 slidably supported on the bracket 366 and movable by
cylinder 368 as seen in FIG. 7. An adjustable stop 365 .
is threaded through block 367 attached to arm 306 and in-
cludes end 369 which engages the step cut block 362 de-
pending upon the actuation of cylinder 368, to provide a
greater or lesser angular spacing between arms 302 and ;
306. This compensates for two sizes of wire fabric where
a greater extension is required on the extending free ends
, .:
of circumerential wiree for prebending the wires to form
the cylindrical cage. This also accommodates different
: , .:
amounts of overlap required for welding different wire
:: :;' . '
sizes. A limit switch 371 is actuated by a plunger 369' ~ - -
extending through stop 369 to provide a signal indicat-
ing when the wire fabric is registered. - -
Drive arm 306 includes a programmable rotary limit ,~
switch unit 370 for detecting the angular relationship
.:
between arms 306 and 302 and providing a control signal
25 representative thereof to control the actuation of rotary ~
drive 320. Unit 370 includes a plurality of limit switches ~ ;
: .
. .
' ' .
~ 29-
::
1045514
. . ~
and having a rotary shaft 374 on which there is provid~
ed a plurality of cams for sequentially actuating the
limit switches within unit 372 as the angular relation
between shafts 302 and 306 changes. Shaft 374 is coupled
to sprocket 375 (FIGS. 7 and 8~ mounted to collar 334. A
chain 376 (FIG. 7) couples sprockets 375 and 377 such
that a change in angular position between arms 302 and
306 will rotate shaft 374.
Additionally, drive arms 306 include means for detect-
ing the end of the wire fabric and for engaging the wire
fabric for squaring the fabric. The detecting means in-
cludes a shoe 380 having a shaft 382 extending through a
sleeve 384 mounted to a cross support member 386 extend~
ing between the spaced arms 306. The end of shaft 382 is
coupled to a multiple position limit switch 388 by a pivot
connection 387 and arm 389. As the wire fabric engages
the contact shoe 380, it will move rearwardly actuating
limit switch 388 which provides control signals for con-
trolling the motion of the means feeding the wire fabric.
Shoe 380 fits within a recess formed in a continuous
I pusher block 390 which extends across the length of the
i ~ .
combing assembly 300 and which is mounted to a backing ~
plate 392 also secured to cross channel member 386. ~`
Once the edge of the wire fabric has been detected
and shoe 380 pushed rearwardly as indicated by arrow E
!:
' ~:
30.
,~
" ~ ~ , . , . . ; ~ , .:
16345S14~
,'''; .
in FIG. 7, limit switch 388 generates an additional
signal initiating deceleration of rotary actuator 320
(FIG. 11) for advancing drive arm 306 and comb support
arm 302 in a direction opposite arrow D in FIG. 7 while
pushing the wire fabric (in one instance) until the comb
platè stop 333 prevents further rotation of arm 302. At ~.
a point determined by signals from limit switches 388
and 370, the comb 325 is lowered such that it misses `-
the last transverse wire. As arm 306 continues swinging
10 in an arc, the wire fabric is forced between the teeth `
o the now lowered comb 325 straightening the ~ree ends
o~ the circumferential wires. Thus, the comb assembly
300 inaludes not only combing means but means for provid-
ing relative motlon between the wire fabric and the comb-
ing means and means for detecting the ends of wire fabric
for controlling its motion through the machine. Having
described the structure of the combing assembly and brief-
ly described its operation, the continued description of ~;
the gripper assembly slide and carriage is now presented
in conjunction with FIGS. 9~
The slide and carriage assemblies 280 and 280', ~ -
respectively, (FIG. I1) comprises an external slide mov-
ably mounted with respect to the internally positioned
- carriage. The slide comprises upper and lower plates
; ~ 25 400 and 402 each secured at opposite ends to slide end
~ ;....
'' ',;:,.
10~5514 ~
plates 274 and 276. Plates 400 and 402 are vertically --
spaced and supported along opposite edges by a plural- .
ity of vertically extending support members 404. This
construction defines an interior space in which the .
5 carriage cross member 410 is positioned. Cross member ..
410 comprises a pair of rails 412 joined by support
members 414. Rails 412 are spaced from each other to -~
permit.clearance in a horizontal direction o about 2 `
inches between the outer edges of rails 412 and verti~
,," '' . '
10 cal support members 404 of the slide. ::.::.
Plates 274 and 276 include relatively large aper- .
tures (not shown) permitting the rails to extend out~
wardly therefrom without contacting the slide end plates
and terminating in carriage end plates 414 and 416. Be- .-- :
tween the carriage cross member 410 and the slide plates
..
400, 402 and slide end plates 274 and 276, there is posi-; :.
tioned a plurality.of ai:r bearings of two varieties. `~
First, there is a plurality of elongated air bearings
418 interposed between which there is provided circular
20 adjustable air bearings 420. To provide lateral support ~: :
preventing shifting of the slide with respect to the
: carriage cross members, air bearings are also provided ~ :
.~ on each of the end walls of the slide assemblyO Air ~:
. bearings 418 and 420 are positioned on both the upper
; 25 and lower surfaces of the carriage cross member such
. .' .:.
.,
: ' -
10~5514
, . .that the carriage cross member is sLidably held within
the slide plates 400 and 402 and provided with an inter-
engagement approaching zero friction at the upper and
: , 'lower surfaces and along the end walls such as cross
. . .
5brace 414a tFIGo 10) with respect to end plate 274. A
suitable source of air pressure ~not shown) is coupled
to each of the air bearings which are commercially avail- -~
able from the Air Float Corporation of Decatur, Illinois. ;~
Intercoupling the slide assembly and the carriage i;
cross member is at least a pair of spring interconnec-
.
tions 425 (FIG. 10). Unit 425 includes a shaft 424
secured to the carriage cross member and slidably extend-
ing into a housing 426 secured within an aperture of one ~;
of the vertical extending support members 404 of the
slide. A spring 428 having a spring constant K1 engages
the housing 426 and a thrust washer 429 mounted to shaft
424 to couple cross member 410 to the slide by means of
a spring 428. The construction of unit 425 is disclosed ~; ;
in greater detail in U.S. Patent No. 3,543,609 issued
December 1, 1970 to D. J. Borodin in FIGS. 24 and 25 of
I such patent. It is noted that only one unit 425 is shown.
In the preferred embodiment, two or more sprlng coupling
units spaced along the edge of each gripping member spring
couple the slide to the carriage cross member.
..
, 25
"~
'. . ' .
. ~ . .
` 33-
, ' ,
~ 5S~ ~
In addition to the spring coupling, means for de-
tecting the acceleration of the carriage assembly and
i.. .
the slide is provided. The acceleration detection ;
means 430 comprises a shaft 432 coupled at one end to
the carriage cross member 410 and extending through an
aperture 433 in support 404. Slidably coupled to the
.
e~tension of shaft 432 outside of the slide by means of -
a cylindrical air bearing 434 is a seismic mass 435. Air
bearing 434 is coupled to a pressurized source of air
(not shown). The seismic mass is seated against a thrust
washer 436 against which a spring 438 having a spring
constant K2 and surrounding shaft 432 is positioned.
Spring 438 is positioned within a housing 439 secured to
a threaded end of shaft 432 by means of nut 431. Spring
constant K2 is related to spring constant K1 as descrlb~
ed below.
Coupled to a downwardly extending leg 440, which is
~: .
a part of seismic mass 435, is shaft 442 of a motion sens~
ing device 444 secured to slide 280. Sensor 444 can be
20 a linear voltage differential transformer or other suit- ~
able sensing device which will provide an output signal ~ -
directly related to the relative motion between seismic
mass 435 and the slide. ~This signal is utilized to con-
trol acceleration of the carriage assembly as described
below in conjunction with FIG. 9. Before discussing this
. :
: :
:
' ": '
. .
~ 34- ~
... , -. - .
..... ~ .. . ... . . .. . . ... . . . . .. . . .
: :
~L~45S1l ~
aspect, however, the carriage drive is discussed in
conjunction with FIG. 11.
!, ` i :
The carriage end plates 414 and 416 are secured to
carriage slide plates 450 and 452, respectively, which
5 in turn are rollably coupled to guide rails 84 and 82, ~.
respectively, of the machine support structure as best ~
seen in FIG. 11. Plate 450 includes two pairs of verti- -` ;
. , .
cally spaced rollers 455 which span the upper and lower
surfaces of guide rail 84 and a pair of horizontally :~
10 oriented and spaced rollers 456 engaging the inner sur- : -
face of guide rail 84. Plate 452 includes a similar con- ~ ;
struction ~or engaging guide rail 82. The ca:rriage is
driven by means o drive gears 460 at opposite ends of
a drive shaft 462 and which are positioned to engage
teeth 89 of drive rails 86 and 88. The drive shaft 462 :
extends through elongated apertures 464 in slide end `~ ;
plates 274 and 276 (to permit relative motion between
the slide and carriage without interference) and termin-
ates in a transmission 465. Transmission 465 includes a
20 right angle drive and is driven by a variable speed :
hydraulic motor 466 which receives drive signals con- ~
trolled in part by the output of sensor 444 for control- : :
ling the motion of the gripper assembly on which it is
mounted. Each of the gripper assemblies includes similar
drive and control structure. Having described the con-
.. . . .
struction o~ the slide and carriage assembly, a description
~,~
. 35.
',"',".'.
~455~
of the function and control of this unique structurei5 provided in conjunction with FIG. 9.
Initially, it has been discovered that if material
to be formed into a circle is gripped at opposite ends
by gripping members which are free to rotate without
resistance, as the ends are brought together along a
straight line in the same plane, a perfect circle is
formed. This assumas, of course, that the material is
free to deflect out of the plane of the ends helcl by
the gripping members. In order to utilize this dis-
covery in the present apparatus where it is desired to -
form a cylindrical wire fabric cage held in position
for subsequent welding, it has been determined that the
carriage drives should be positively driven in synchron- -
ism with rotation of the gripping members such that at
each point of travel the cage will have a true circular
shape. The gripping members should be positively rotat-
ed in synchronism with the carriage drives for each of
the gripping members such that as the gripping members
arr.ive at a midpoint as shown in FIG. 15, the gripping
jaws will have rotated 180 forming the completed circu-
lar cross section construction. -
Should the cage deviate from a circle during the
.
forming process, a resistive linear force component is
exerted on the slide assembly on which the gripping
.. . .
:. : .
~. .
36~
, ~.
- ., ~ . . . ... , . . , i , . .. , ... . :.
,: , ~, -. . : , . . ... ,.. . .. . , ~ , . . . . . . .. ..
~L0455~
members are mounted. This force is directly related to
the resistance to translation of the slide due to the
natural tendency of the material to assume circular shape
and is converted into relative motion between the slide
5 and carriaye which can be detected by the inertially re- -
sponsive detecting means. The sensor output signal is
employed to change the carriage speecl of both of the
gripping assembly carriages to compensate for the momen-
tary tendency of the material to form anything other than
a perfect cylinder. In order to generate a signal which
is directly proportional to the resistive force of the
fabric and, therefore, the deviation of the forming of
the fabric from a perfect circle or cylindrical shape,
the spring constants Kl and K2 are chosen with respect
15 to the seismic mass and mass of the slide assembly to ~-
satisfy the following equation with respect to the ele~
ments identified in FIG. 9:
K2 . Kl = m2 ml
Assuming a frictionless system, which is certainly
true of the seismic mass, which is mounted on air bear-
ings and is virtually true of the slide which has a re-
- : :: . .
latively high mass and, therefore, its accelerational -
force will be much greater than any frictional force
. ' ' '.
which is insignificant. Thus, the following relation-
ship exists between the slide and seismic mass~
., .', ,' ':.
'":' ;.,
~ 37. ~
' : .:
1~)455~4 `
~ ,.
Deflections due to acceleration
~L2 = F2 = m2a2
K2 K2
l~Ll = F2 = mlal
Kl Kl . .
but because ml = Klm2 K2
K2 = Kl~m2)
therefore
~L2 =~2 x a2 = mla2
K~ Ki
, . ~mlJ ' :
since al ~ a2 mla2 ~ mlal ~
Kl K
` . ' . .
Hence deflections due to acceleration are equal.
The purpose of the mechanism 430 is, therefore, to
cancel out the effect of the acceleration in the reading
of the deflection. The remaining deflection registered `
, , ,
by sensor 444 is essentially due to the force produced by
the cage due to its deviation from a perfect circle at
lS any point during the forming cycle.
FT = total force acting on spring 428 ;~ -
= F ~ F2
. . '''':
where Fc = force exerted by cage
F2 = orce due to acceleration
1 : ,,. ~ .
~ 20 Fl = force acting on seismic
,
mass due to acceleration ~
' ~ .,.. :,
'I ... . . .
., . .: '
. 38.
: .
, ' ' ' '
i, , , . , . . ,, , . , ~ . ..
~LT = total deflection of spring 428
= I~Ll + ~Lc -
where ~Lc = deflection due to cage
then ~LT ~ ~Ll = QLc
= ~LT - ~L2 = ~Lc
This relative motion is detected by the LVDT sensor
444 (FIG. 10) or a Servalve sensor 444' (schematic FIG.
9) and converts such motion into an electrical signal
which can be employed to control the speed of the carriage
10 through the drive motor 466 (FIG. 11). The feedback of
the force Fc through the deflection detected by sensor
444 enables the maintenance of the proper relationship ..
between the angular position of the grippers and that of .:.
the carriage. An accelerometer also could be coupled to :.
: . :
the slide to detect the acceleration of the slide and em-
ployed to develop a signal together with a load cell - :
coupled between the slide and carriage in place of spring
428. The difference in the output signals would then be :
employed to provide the speed control signal for the .. :
20 carriage. .`; :
Thus, given any length of wire fabric, the gripping
~ ~ assemblies are moved toward each other while the gripping .:
:~ jaws are rotated 180 i~n synchronism to form a perfect~-:
circle with self-compensation for any out of synchronism .~.
condition caused by the gripper jaw slide being in advance ..
: ~ '
:. .
39O
: - .
1()4~5~
or behind the rotational motion of the gripping jaws,
; which condition deviates from the locus of points of
the wire when a cylinder is being formed. The control ~;
system which operates as an inertia detection system,
can be employed to automatically adjust the motion of
gripping jaws to form the fabric into a perfect cylin-
der regardless of the fabric length, the ~ti~fness or
the like. Although the parameter control in the pre- `
ferred embodiment is the speed of the slide, it is
readily apparent that the rotational drive for the
gripping jaws likewise could be speeded up or slowed
down to compensate for the asynchronous motion between
the jaws and their slides. Also, the control system ;;
can be used in machines for forming single wire circles ;
15 or cylinders from any deformable planar stock. ~-
~ . ~. ' . .
Once the gripper assemblies 30 and 40 have advanced ~ ;
together to a position shown in FIG. 15, the free ends -;
of the circumferential wires are overlapped and once ad-
justed to li~ immediately adjacent each other by the -~
actuation of cylinder 253 as described above in conjunc-
tion with FIG. 11, the cage is in position for welding
by the welding apparatus 50 as best seen in conjunction
..
with FIGS. 17-19 now described. ~
Initially, it is noted that upset welding with - -
orthogonally oriented wires is known. To distinguish
"
'
'''', '
':
~045S~4
the unique welding method and apparatus of this inven-
tion, the term "line upset weld" is employed. This term
thus refers to the longitudinal alignment of the ends of
the circumferential wire providing a line contact there-
between before welding. The resultant line upset weld
- can be complete (100%) as shown in FIG. l9A or partial
to join the wire ends.
The welding unit 50 as best seen in FIGo 17 compris-
: . .
es a carriage 500 movably mounted between transverse sup-
port members 502 and 504, each of which includes a guide
. .
; rail 506 on facing surfaces thereof. Carriage 500 includes
a pair oE support beams 508 and 510 having a plurality of
pairs of vertically spaced rollers 515 which span upper
.~ . . .
and lower surfaces of the guide rails 506 on beams 502
and 504 for providing support for carriage 500 permitting
its motion along these beams as shown by arrow F in FIGS.
.
2B and 17. For actuating carriage 500 there is provided
a hydraulic cylinder 520 mounted on backing plate 522 in
turn attached to the support beams 75 and 76 on opposite
sides of the forming machine.
Cylinder 520 includes shaft 524 extending therefrom
and coupled to end bracket 5I4 of the carriage for moving
; the carriage in a stepwise ~ashion between various weld-
~,
- ing positions as described below. As seen in FIGS. 2B
and 17, the carriage 500 includes a plurality of welding
heads 525 such that a plurality of circumferential wire
: ' .
.
K , 41-
~0455~
ends can be welded simultaneously. Each welding head
525 includes a pair of electrode jaws 530 which are
pivotally mounted between the ends of a pair of down-
wardly depending arms 540 by means of insulating pivot
connections 532. A jaw cylinder 5~5 i9 pivotally coupled
between the electrode jaws at an end remote ~rom their ~ ~
pivot connection and actuatable for moving the jaws be- ~ ;
tween an open position as seen in FIG~ 17 and a c:Losed
. ~ .
position under constant pressure as shown in FIGSo 18
10 and 19. The cylinder is insulatively mounted to at least ;~
one of the jaws so as not to short out the electrodes.
Each of the electrode jaws 530 includes a cylindri-
cal recess 532 for partially circumscribing a circumfer-
ential wire.
Arms 540 are mounted to a slide 550 slidably cap-
`tuxed by guide rail 560 for vertical motion therealong
in the direction indicated by arrow G in FIG~ 17~ A
cylinder 555 supported between arms 508 and 510 by means
o a plate 556 includes a shaft (not shown) coupled to
slide 550 for raising the slide and, therefore, electrode
jaws 530 ~etween an inoperative position and lowering the
. ~:
jaws to an operative position. Mounted to each of the
slides 550 are power supplying transformers 554 for
supplying operating power to the electrode jaws. ;~
~"
".' ',' ': ~
. ' ~ ., ' :
`' 42- ~`
~ . , , . ., .. , , ., : . . .. .. . . . ....
~455i~L~
... . .
To provide a line upset weld, the jaws initially
are clamped against the edges of a pair of aligned,
overlapped circumferential wires 12 as seen in FIG~ 18B.
By virtue of the comb assembly stop discussed above, the
overlap can be selected to fall within the desired range
of 0.25-0.75 inches to provide the upset weld desired. -~
.. ..
With the jaws clamped with a predetermined pressure, the ~;~
;, power supplies are actuated for heating the wires and
fusing them as shown in FIG. 19. Closely controlled ;
.. ...
values of clamping pressure, current, current duration
and holding time enable a 100% line upset weld to be
made. The resultant structure is shown in FIG. l9A and
comprises a 100% line upset weld with greater strength
than available with typical offset welds previously pro~
lS vided with wire cage formation. Also, with the circum-
; ferential wires coaxially welded, skewing of the reinforc-
ing cage is avoided. Addltionally, the flash wings 13
extending from opposite sides of the welded junction of
the circum~erential wires serve as an anchor when the
concrete is molded around the cage so formed.
Once one of the welding steps has been completed, ~ ~:
~ - the cylinder 545 is actuated to vpen the jaws whila the
,~ jaw assemblies are raised by cylinders 555 and the weld-:, . ,
j ing heads are moved an incremental distance corresponding
, 25 to the spacing between adjacent circumferential wires and,, ' . -
~ : ,.''
43. ; ~
- ~Lo~55~
the welding cycle is repeated. With this con~truction
several welds are made simultaneously and the cycle is
repeated as required to weld each of the circumferen-
tial wire junctions. The following parameter values
5 have been found effective in providing 100% upset weld
using the welding unit construction disclosed herein.
Wire Wire Welding Jaw Time
D iameter Overlap Current Force of Weld
.
.175 in. ~25 in. 7900 Amp500~ O3 sec.
.226 in. .25 in. 8000 Amp650~ .5 sec. i
.292 in. .4 in. 8800 Amp900~ .5 sec.
.306 in. .25 in. 8800 Amp900$~ .5 sec.
Since the bell end circumferential wires of the
fabric are frequently spaced a greater distance apart~
than the remaining wires, in the preferred embodiment
a sécond welding carriage assembly 500' (FIG. 2B) is
provided with a single welding head 52S'. The construc-
tion and control of this unit is the same as that of
units 500 and 525 and is not repeated herein. ~;
Once the welding step has been completed, the upper
gripE7ing jaws (now rotated to be in the lower position)
:::
are opened by actuating the jaw latch cylinder 260 and - - ~
.. ...
jaw actuating cyllnder 270 permitting the completed cy-
lindrical cage to be removed from the jaw assembly in a -
25 direction indicated by arrow 11 in FIG. 20 which is at
:,
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a~4. ~
1~45S~4 :
right angles to the motion of the fabric into the machine
and transported by means of the outfeed conveyors 60.
Conveyor 60 is a powered convenyor bed mounted on scissor
jacks 580 and tilted to provide transportation of the com-
pleted cylindrical cage from the forming machine to thesuccessive bell end forming machine disclosed in detail
in our concurrently filed Canadian application entitled
PIPE CAGE END FORMING MACHINE Serial No. 243,951, filed
January 19, 1976. The outfeed conveyor 60 includes a
pair of spring adjustable arms 582 on either side of the
cage to provide stability to the cage as it is transport-
ed from the forming machine into the bell end forming
machine. Having described the construction o~ the
machine, a description of a cycle of operation is now
; 15 presented together with the control elements for actuat-
ing the various cylinders and motors disclosed herein.
OPER~TIO~I
At the beginning of a cycle of operation the infeed ;
carriage and gripper assemblies are positioned as basi-
20 cally seen in FIG. 12. The movable clamping means of ~
the carriage assembly is, however, in an open position ;~ -
ready to receive a section of wire fabric from the pre- -
.,, ., :: .
ceding fabric shearing stage. As the gripper assemblies -
complete forming operation on an existing piece of fabric
and welding is completed, the infeed carriage assembly is
receiving the next successive section of wire Eabric which
.
, '' " '
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l~SS~L4
can be the same length as the preceding section or can
be any number of different lengths for forming ,a differ-
ent diameter cage. A detector 702 (FIG. 21) is position-
ed slightly upstream of the infeed clamping means to de-
tect the incoming wire fabric and is coupled to the in~
feed logic circuit 700 for supplying a signal to the
logic circuit indicating that a section of wire is pre-
sent. The infeed logic circuit generates a signal to
actuate cylinder 190 for closing the clamping means and
also actuating motor 157 for advancing the wire fabric `~
by the movable belts of the clamping means until the lead-
ing transverse wire of the fabric is detectecl by a second
transverse wire detector 704 (FIG. 21) positi.oned on the
clamping assembly 160 at the leading edge and coupled to
circuit 700. Circuit 700 responds to a signal from de-
tector 704 to deactuate motor 157 with the leading trans- ;~
verse wire of the fabric section protruding slightly
forwardly of the clamping means associated with the in- ~`
feed system. ;
At this time, the welding step is being completed ~;
and subsequently the gripping }aws are in an open posi-
tion to receive the subsequent section of abric. Upon
deactuation of motor 157, the logic circuit provides a
control signal to motor 116 to actuate infeed carriage
100 advancing the wire section to a position slightly
~. .
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. .
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46.
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downstream of gripping assembly 30. A counter 706
coupled to the infeed carriage provides a plurality of
pulses to circuit 700 corresponding to the length o
travel of the infeed carriage and, therefore, the posi-
tion of the wire fabric. Circuit 700 includes a digitalmemory and comparator for comparing the incoming pulses
from counter 706 with the number of stored counts corre-
sponding to the desired end position of the infeeci
carriage. As the stored count is reached, circuit 700
generates a decelerating signal applied to initia].ly
slow down and then stop motor 116 to stop the infeed
carriage. As this occurs, a signal from circuit 700
actuates motor 157 to expel the fabric section rom the
infeed means into the awaiting gripping assemblies.
At the same time motor 157 is actuated the ineed
logic circuit 700 applies a signal to the gripper assem-
bly logic circuit 710 which actuates cylinder 286 o the
gripping assembly 30 for raising guide ramp 282 to guide
the leading edge of the fabric between the open jaws of
20 this gripping assembly. It is noted here that the comb- ;
ing mechanism 300 of assembly 30 is in its raised posi- ~-
tion as seen in FIG. 13.
The wire fabric enters gripping assembly 40 and con-
tacts the lowered comb and detection unit 300, contacting
shoe 380 which actuates limit switch 388 (identical to
. . .
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structure shown in FIG. 7) which applies signals to ;~
.~ . .
circuit 710 which responds to apply a control signal to
motor 157 via the feedback coupling 715 between circuits
710 and 700 which causes the successive deceleration and
stopping of the dxive motor 157.
Upon actuation o limit switch 388 by fabric section
10 indicating the leading edge of the fabric is extended
through the jaws of gripping assembly 40 such that the
leading transverse wire is immediately adjacent the up~
-~.:
stream side o the comb, circuit 710 generates a signal
applied to actuate comb cylinder 340 to lower the comb
into position. ~ limit switch 373 (FIG. 21) is position-
ed on the comb assembly to be actuated when the comb is
l , : .
fully lowered. Switch 373 is coupled to circuit 71Q to
I5 actuate motor 320 o the comb assembly or forcing the `
free ends of the circumerential wires through the comb
straightening them. During this step the fabric section
is supported by the open ineed means. Limit switch 370
:: : .
: .
, is actuated indicating when the combing step is completed.
!
I ; 20 Switch 370 is a multiple-position switch which is coupled
.
to circuit 710 for applying a control signal to rotary
actuator 320 or successively decelerating and stopping ~ -~
. .
~ ~ rotary actuator 320 for smooth operation.
: . -:
Upon actuation o limit switch 371 coupled to cir-
25 cuit 710 and indicating that the leading edge of the -
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.
48. ;
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~L~4551~
fabric is in its predetermined reference position, jaw
; cylinder 270 of assembly 40 is actuated closing the
: pivoted upper jaw which when closed, actuates a limit
switch 715' coupled to the gripper assembly logic cir-
5 cuit for subsequently actuating the latch cylinder 260 ~
for locking the gripping ~aws of gr:ipping assembly 40 in :
position.
Upon completing the combing of the leading edge o : :
the infed fabric, the signal from jaw closed limi.t switch ;~
. 10 715' circuit 710 responds to actuate carxiage motor 466 :
:
of gripper assembly 40 and the equivalent motor 466 of
gripper assembly 30 causing the gripper assemblies to
spread apart moving in opposite directions. A signal ~ :~
is also applied to circuit 700 via conductor 715 to move
. 15 the infeed means to the left end as seen in FIG. 12. At .. :
: -
i this time the gripper jaws of assembly 30 are still in
an open position. A detector 712 positioned on gripper
~ . assembly 30 to detect the fabric passing therethrough as
; the gripper assemblies move outwardly from the center .:
. 20 position and provides a signal when the trailing edge
of the fabric section has approached a position such that
the trailing transverse wire is slightly downstream of ~:
the comb associated with assembly 30O The signal from
detector 712 effects the generation o~ a signal by cir- :
cuit 710 to decelerate the gripper carriage motors 466 .
.
.
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and simultaneously actuate rotary actuator 320 of the
left gripper assembly to lower the comb and detecting
assembly 300 to its reference posltion and lower the
comb into its operative position.
As the drive arm 306 of assemb]Ly 30 continues ;;;
swinging down to the right in the ~igures forcing the
comb through the ends of the trailing circumferential
wires until the detection shoe 380 engages the free
trailing edge of the i~abric and actuates limit switch
10 388. Switch 388 is coupled to circuit 710 for develop-
ing a signal applied to decelerate and stop comb rotary `-~
actuator 320 and also activate the jaw locking and latch
cylinders associated with gripper assembly 30 after comb-
ing has been accomplished.
With the free ends of the leading and trailing edges
of the fabric combed and, therefore, straightened, and
the fabric clamped at a position spaced inwardly slight-
ly from the free ends, the forming operation is commenced,
initiated by the jaw closed limit switch associated with
20 the jaws o E assembly 30. Circuit 710 applies a signal to
the carriage motors 466 of both gripping assemblies to ;
. . .
drive the gripper assembly carriages toward each other ~o
a center position (FIG. 15) ~7hile simultaneously actuat-
ing motor 225 of each of the gripper assemblies to provide
25 rotation of the gripping jaws o E each assembly.
., .
50. ~
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1~:)4S5~4
Detectors 444 of each assembly detect any motion
caused by deviation of the synchronous motion between the
..
' rotationof the gripping jaws and the lineal advancement
. . . .
of the gripping assemblies to correct the drive speed for
5 motors 466. Circuit 710 includes conventional dual clos-
ed loop servoamplifier systems coupled to detectors 444
and motors 466 for providing this control function for
., . . ::
,, each of the gripper assemblies. The gripper assemblies
.,
, i~ advance to the center position as shown in FIG. 15 where-
10 upon they engage a limlt switch 714 detecting the comple- -
~l, tion of their travel and which initiates actuation of
.. ..
cylinder 253 for abutting the free ends of the circumfer-
I ential wires. After a predetermined delay suf~icient to ;~
achieve this abutting operation, circuit 710 generates a
pulse applied to the welding logic and timer circuit 720
via conductor 716 to initiate the welding sequence.
.. .
. . . . .
I Upon receipt of a control`signal from circuit 710,
:.i :
l~ ~ the welding control circuit 720 actuates cylinder 520 to
.. . .
;¦ ~ horizontally position the welding heads at a predetermin-
'1 20 ed position aligned with overlapped wire ends. The mo-
~ tion of slide 500 is detected by a multiposition limit
, . ~
:f : ~ switch 722 and cam means positioned between the slide and
f~; the guide~support~rails 502 and 504 such that the position
; of the slide along the support members is always known.
.~ . , ~ : :
~ 25 Once the initial position has been reached, limit switch
.. .
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722 actuates circuit 720 to in turn actuate cylinders
555 to lower the welding jaw electrodes. Once the
electrodes are in a lowered position, a limit switch - ~ .
724 is actuated indicating this positioning of the weld-
ing heads whereupon cylinders 545 are actuated to clamp .~.
the welding jaws around the abutted ends of the circum-
ferential wires as seen in FIG. 18B. Simultaneously,
the welder power supply including transformers 554 asso-
ciated with each welding jaw are actuated for a predeter- -
mined time depending upon the diameter of the wire for
providing a 100% upset weld. To provide adjustable clamp-
ing pre~sure by the welding jaws, the cylinders 520 are ~:~
. . ; .
commonly coupled to a pressurized source O:e hydraulic
luid including an adjustable pressure regulator 519.
After a conventional timer circuit included in weld-
ing control circuit 720 has run out indicating the weld-
ing operation has been completed, the jaw cylinders 545
are actuated to open the jaws~ Cylinders 555 are then
actuaked to raise the welding heads and c~linder 520 is ` i
moved incrementally to the next welding position where- .
upon limit switch 722 generates a second welding sequence
initiation signal.
~ - Thus, each welding step is repeated until all of :
- . . the circumferential wires have been welded in 100% upset
fashion as seen in FIG. l9A. Upon complekion o~ the last
welding sequence, circuit 720 provides a control signal
~ , , .
- 52. . .: :
. .
~455~4
to the gripper assembly logic circuit 710 via intercon~
necting conductor 725 to actuate the jaw and latch cylin-
ders 270 and 260, respectively, of each gripping assem-
bly permitting the release of the completed cylindrical
cage as seen in FIG. 20. This signal likewise can be
employed to actuate the powered outfeed conveyor 60. A
cage detector can be employed to detect when the complet-
ed cage has cleared the gripping assembly area whereupon
a new cycle of operation can be commenced.
It will be appreciated that with the unique gripping
assemblies of the present invention, including the rotat-
able and lineally movable gripp~ng jaws which include
detecting means for assuring that any length of wire
fabric will be gripped in-a predetermined re~erence by
15 the pair of gripping jaws, the forming machine of tlle ~ -
present invention can successively manufacture different
sized cages from different lengths of fabric without re-
adjustment of the machine. This is particularly useful
when successively manufacturing inner and outer reinforc-
ed cages for relatively large concrete pipes.
It will be understood by those skilled in the art
that various modifications ~ the preferred embodiment
disclosed herein can be made. Further, it will be under-
stood that the system is not limited to the manufacture
of cylindrical pipe reinforcing cages from wire fabric.
.~
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53~
~L~455~
,,. .. ~ :
It has equal application for manufacturing closed loop
objects from any type of material including sheet metal
and plastic. Further, the inertial detection and speed
control utili2ed in conjunction with the gripper assem-
5 bly will have application to other types of machinery. -
In addition, the infeed carriage likewise can be employ- ~ ;
ed with a variety of equipment requiring positive advance- ~ ;
ment of materials with continuous support along the length -
of travel of the material being transported. In some em-
bodiments the carriages for the gripper means can be
mounted in a virtually frictionless fashion and only the
gripping means rotated to advance the ends of the work-
piece together. ~hese and other modifications and uses
of the present invention will, however, fall within the
1 15 various aspects of the invention as defined by the append-
ed claims.
This application is a division of Canadian patent
~` application Serial No. 243,958, filed January 19, 1976.
,
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