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Description  |
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This invention relates to the manufacture of assemblies of cloth-pocketed
upholstery springs, referred to in the furniture trade as "Marshall"
constructions, for use as the spring cores of mattresses, seat cushions,
and the like.
More particularly, the invention provides an apparatus for assembling
successive strips of pocketed springs, one strip at a time, into a unified
whole by connecting the interspring web of pocket material of each
successive strip to that of its predecessor strip at intervals along the
two strips. In that fashion, as many strips of springs as are necessary
are joined successively to form a spring core of the desired dimension,
staggering the interstrip connections so that, along its own length, each
interior strip of springs is connected alternately to its flanking strip
on one side and then to its flanking strip on the other side.
The spring assembly itself, and the basic method for its manufacture, are
disclosed and claimed in my U.S. Pat. No. 4,234,984.
The specific form of assembly apparatus disclosed contemplates the use of
ultrasonic thermal welding devices for joining the strips of pocketed
springs together, and, preferably, the utilization of a thermally weldable
fabric as the pocket material. The invention, however, should not be
regarded as limited to those particulars, inasmuch as other known
instrumentalities for joining layers of fabric, e.g., by sewing or by the
use of connectors such as grommets or rivets or clamp fasteners such as or
analogous to hogrings or staples, may also be employed.
It is the ultimate object of the invention to provide apparatus for the
assembly of the dimensionally-stable Marshall construction of Pat. No.
4,234,984, earlier referred to, on a production basis, and one which may
lend itself to further automation of the procedure so as to form spring
cores from strips of pocketed springs assembled row upon row as fully
automatically as the assembly of open-coil spring constructions is now
conventionally performed.
Further and more specific objects will become apparent and the invention
understood by reference to the following specification, taken in
conjunction with the accompanying drawings, in which:
FIG. 1 is a fragmentary front elevation of a preferred assembly apparatus
in accordance with the invention;
FIG. 2 is a sectional side elevation of the same apparatus taken on the
line 2--2 of FIG. 1;
FIG. 2A is a fragmentary face view of the spring assembly produced by the
apparatus of FIGS. 1 and 2, as it might be viewed from the righthand side
of FIG. 2, issuing from the assembly apparatus;
FIG. 2B is a fragmentary end view of the spring assembly of FIG. 2A, e.g.,
as seen from the top of FIG. 2A, illustrating the placement of the
interstrip connections;
FIG. 3A is an enlarged fragmentary and sectional side view of an interior
detail of the apparatus;
FIG. 3B is a fragmentary elevation of the same detail;
FIG. 4 is an enlarged and partly sectioned fragmentary side view of the
assembly station of the apparatus;
FIGS. 5, 6, and 7 are enlarged fragmentary and sectional elevations of the
apparatus as seen in FIG. 2, illustrating the sequence of positions of the
operative parts of the disclosed apparatus during a single cycle of
operation;
FIG. 8 is a plan view of the assembly station of the apparatus poised for
the beginning of a spring assembly;
FIG. 9 is a front elevation of the same, showing the first two strips of a
new assembly positioned to be joined;
FIGS. 10, 11, and 12 are respectively plan, elevational, and sectional
views of the anvils upon which the connections between successive strips
are made; and
FIG. 13 is a diagram of the electrical and fluid circuitry which governs
and powers the operation of the apparatus;
FIG. 14 is a sectional side elevation of a modified form of the apparatus,
similar to FIG. 2;
FIG. 15 is a fragmentary front elevation of the modified apparatus shown in
FIG. 14;
FIG. 16 is a fragmentary enlargement of a portion of the modified apparatus
as shown in FIG. 14; and
FIG. 17 is a fragmentary sectional elevation corresponding to FIG. 16 and
taken through the axis of symmetry, as shown in FIG. 15.
BRIEF DESCRIPTION OF THE INVENTION
As earlier noted, the invention contemplates the formation of a
pocketed-spring construction 10 (FIG. 2A) by joining successive strips 12
of such springs to one another, seriatim, to build the assembly.
As in prior constructions of the pocketed-spring type, it is further
contemplated that the successive strips of springs so joined may, if
desired, be the successive runs of a continuous strip of springs, laid
upon itself row upon row, in serpentine fashion.
The interstrip connections 14 are made by joining the interspring webs of
the pocket material of adjacent strips, preferably at intervals of two
springs along each of the successive strips, as each new strip is added to
build the construction to the desired size. The interstrip connections are
staggered by one spring from strip to strip with the result (referring to
FIG. 2A) that each spring, in addition to being integrally connected by
the pocket material to the adjacent springs of its own strip, is likewise
connected, by the apparatus, to its diagonal neighbors of each adjacent
strip. As each group of four springs surrounding each such interstrip
connection 14 is secured together as a tight cluster, and as each interior
spring is simultaneously a part of two such diagonally-arranged clusters,
the assembly as a whole exhibits a dimensional stability in the plane of
the construction which is uncharacteristic of Marshall constructions of
the nested spring type, i.e., wherein the springs of successive strips are
nested in the crevices between the springs of the adjacent strips.
The disclosed apparatus for so connecting successive strips of springs into
a unified assembly or construction comprises a support in the form of an
upright rectangular frame 16 having thereon a box-like assembly station 18
which is open top and bottom. A series of aligned retractable probe-like
anvils 20 (FIG. 2) are adapted when inserted into the station 18 to fit
between adjacent springs of a strip of cloth-pocketed springs emplaced
therein, and to engage the web of pocket material between two springs
(FIG. 9). The spacing of the sixteen illustrated anvils 20, eight in each
bank, is such that each bank supports a strip of coils by engagement with
the interpocket web of material between two adjacent springs at intervals
of two springs along the spring strips.
Also carried by the frame in opposition to the line of anvils is a parallel
line of ultrasonic fastening heads 22 movable toward and away from the
anvils. The fastening heads, when inoperative, are spaced sufficiently
from the anvils to permit the emplacement between them of two strips of
pocketed coils, i.e., the strip of coils last connected to the assembly
and the new strip to be connected thereto.
A positioning mechanism 24 serves to hold each new strip of springs in
alignment with the strip of springs previously added to the assembly, and,
in the disclosed apparatus, also serves to index the assembly through the
station for the addition of yet another strip of springs.
In a spring assembly which utilizes barrel-shaped spring coils, as
illustrated, the connections 14 of adjacent strips of springs to each
other may be made simultaneously at two sites along a given interspring
web of pocket material, each connection 14 being located inwardly of and
near the ends of the individual springs, i.e., disposed inwardly of the
assembly from its two load-bearing surfaces. For this purpose, the
fastening heads 22 which connect successive strips of springs to each
other are arranged in pairs, while the anvils against which they press the
four superimposed layers of pocket material of the interpocket webs are
shaped and proportioned so as to fit readily into the space between the
two springs bracketed by the connections between the two previous strips,
i.e., so as to cooperate with the fastening heads in connecting each new
strip to the last.
Alternate ones of the aligned anvils 20 of the assembly station 18 are
connected together as two banks, A and B, which also alternate in
function, and are conveniently, but not necessarily, inserted into the
assembly station from opposite sides. Each bank of anvils is separately
movable on the support to withdraw the anvils from the assembly 10 after
each interstrip connection is made, thus to permit the indexing of the
assembly in the machine direction for the feeding of the next strip of
pocketed springs to be joined. Because the anvils of the alternate bank
were reposed in the voids of the spring clusters formed by the connection
of each new strip, the indexing of the construction by the positioning
mechanism 24 suspends the assembly upon the alternate bank of anvils by
their engagement with the webs between the pairs of springs which lie
between the welds made in the last-joined strip. This indexing movement
also positions the assembly for the reinsertion of the first bank of
anvils, over the top of the indexed assembly, after which a new strip of
coils is fed into place.
To connect successive strips of springs to the assembly by connections
which are staggered or offset from strip to strip, the entire array of
fastening heads 22, and the coil-strip positioning and assembly indexing
mechanism 24 are indexed laterally relative to the spring assembly for
each new cycle of operation, the fastening heads cooperating with one bank
of anvils on one cycle and with the other bank on the next.
The movements of the various parts of the apparatus are powered in
predetermined sequence by fluid power, compressed air in the illustrated
case, under the control of an electrical program controller, each cycle of
which is initiated after a new strip of springs is emplaced for addition
to the assembly.
DETAILED DESCRIPTION OF THE APPARATUS
The Assembly Station
The upright rectangular frame 16 of the apparatus comprises a pair of
widely spaced standards 26, each consisting of a pair of vertical parallel
bars maintained in narrowly spaced relation by a flanged base bracket 28
at the bottom and a flanged anchor bracket 30 at the top. The brackets are
cast to provide sockets to receive the vertical bars of the standards, and
also to provide transverse sockets which receive upper and lower cross
bars 32 which complete the frame.
Extending between the opposed standards within the frame are two vertically
spaced cross beams 34 and 36 of rectangular cross section, each provided
with a mounting flange at each end for screwing the cross beams to the
upright standards.
The spring strip assembly station 18 comprises a laterally elongated front
plate 40 and a deeper rear plate 42, each connected to a pair of side
plates 44 which are shaped and proportioned to suspend the assembly
station from the lower cross beam 36 and to provide mounting sites for the
air cylinders 46 and 48 which separately insert the two banks, A and B,
respectively, of anvils 20 into the assembly station.
Each anvil 20 is formed from mechanical, i.e., thick-walled, tubing which
is milled flat on three sides at equal angles to each other to provide a
triangular cross section with intervening fragmentary cylindrical surfaces
throughout the insertable length of the anvil (FIGS. 3A, 3B, 10, 11 and
12).
Each anvil is rotatably positioned with a flat side up for good contact
pressure against the button tip 50 of the cooperating fastening heads 22,
and is drilled to provide two holes 52 aligned with the fastener head tips
to emit a blast of cooling air from the anvil to lift the pocket material
web, and to cool and set the weld. The tip of the anvil tube is plugged to
limit air egress to the holes 52. The anvil tip is also rounded, as well
as curved along its lower edge, to facilitate the passage of the anvil
between and over the coils of the last-joined row of the assembly, and its
ultimate seating in the bearing hole of the far plate, as the anvil is
inserted into the assembly station.
At its base end, each anvil 20 is tapped with tapered pipe thread to
receive an air-line T-fitting 54, and is milled flat on top so that all of
the anvils of one bank can be locked in proper rotative orientation in one
of the two mounting bars 56 and 58, each of which is angle-shaped in cross
section for adequate rigidity. The vertical flange of each mounting bar is
drilled horizontally to receive the base ends of the anvils, and drilled
and tapped vertically for the set screws 60 which lock the anvils in the
bars. Each is also drilled at its ends to receive the piston rods of the
air cylinders 46 and 48 which reciprocate the bars 56 and 58 respectively
to insert and retract the banks of anvils A and B, respectively, into and
from the assembly station 18 (FIG. 8). The air passages of each bank of
anvils are manifolded to a common supply line by the T-fittings 54 at the
base of each anvil.
Guide bearings for eacn anvil are provided by a bearing bar 62 of
substantial thickness, dowel pinned and screwed to each of the front and
rear plates 40 and 42 of the assembly station (FIGS. 2, 3A). Each bar is
drilled to provide a bearing hole 64 for each anvil of both banks of
anvils, the bearing holes 64 being preferably bored and reamed to size
after assembly of the bearing bars with the side plates in order to align
the opposed bearing holes precisely. The bearing holes 64 are interiorly
tangent to the lower edges of larger holes 66 in the front and rear plates
40 and 42 themselves, whose purpose is to provide relief at the assembly
station for the ruffled flap of the pocket-closing seam of the spring
strips which might otherwise extend into the path of one of the descending
fastener heads 22 to interpose more than the intended four thicknesses of
pocket material between the fastener head tips 50 and the anvils (FIG.
3B).
The side plates 44, as earlier noted, are milled to receive the lower cross
beam 36 of the main frame upon which the assembly station is mounted, each
side plate being underslung from the beam 36 by a straddle clamp 68
screwed to the upper edge of the plate.
To facilitate the actuation of the front bank A of anvils, the ends of the
forward anvil mounting bar 56 are extended beyond the side plates 44 for
connection to the piston rods of the air cylinders 46 mounted on the
outside surface of the side plate (FIG. 8). Also at each end of the front
mounting bar 56 a depending clamping block 70, secured to the underside of
the bar, is clamped to the end of a slide shaft 72 supported in two spaced
slide bearings 74 secured on the outside surface of the side plate 44
beneath the air cylinder 46 (FIG. 4). The slide shaft 72 and slide
bearings 74 support and guide the front bank A of anvils during their
insertion and retraction, but the anvils are nevertheless sufficiently
closely fitted in the bearing holes 64 to transfer the load of contact by
the fastener heads 22 to the bearing bars 62.
The air cylinders 48 for the mounting bar 58 of the rear bank B are
conveniently mounted on the inside surfaces of the side plates, where each
end of the rear mounting bar 58 is similarly carried for reciprocation
upon a slide shaft 76 clamped in depending blocks 78 at its ends, and
slidably journaled in spaced slide bearings 80 secured to the inside
surface of the side plate 44 behind the rear plate 42 of the assembly
station (compare FIGS. 2, 8, and 9).
As earlier noted, the opposed action of the two banks of anvils A and B is
not essential to the invention; by a suitable interfitting comb-like
redesign of the mounting bars 56 and 58, both banks could be inserted in
the same direction, for example, from the rear, if closer access to the
assembly station from the front were found desirable in the illustrated
apparatus (or from either top or bottom if horizontal assembly and
indexing were preferred).
The Mounting of the Fastening Heads And Coil Strip Positioning Mechanism
The fastening heads 22 are movable on two mutually perpendicular axes to
bring the fastening heads into alignment first with one bank of anvils 20
and then with the other, and to move the fastening heads toward and into
cooperation with the anvils, and to retract them for the feeding of a new
strip of springs.
This compound movement, in a vertical plane in the illustrated apparatus,
is provided by a vertically-mounted compound indexing "table" 82 which
spans the cross beams 34 and 36 of the upright frame 16.
Referring to FIG. 4, the primary carriage 84 of the indexing mechanism
supports the fastener heads 22 and coil-positioning mechanism 24 for
transverse indexing relative to the spring assembly, whereas the secondary
carriage of the indexing table provides for vertical movement of the
fastener heads into engagement with the anvils.
Specifically, each of two primary track shafts 86 of the indexing table is
bolted to one of the cross beams 34 and 36, longitudinally thereof, to
support the laterally shiftable primary carriage 84 of the indexing
mechanism. The primary carriage 84 comprises four anti-friction
slide-bearing blocks 88, two on each horizontal primary track shaft 86,
which are connected together in spaced relation on the track shafts 86 by
a rectangular subframe 90 which carries the positioning mechanism 24.
The slide bearing blocks 88 are also spanned vertically by two vertical
track shafts 92, each of which carries two slide bearing blocks 94 which
are secured in spaced relation to a cross beam 96 to constitute the
secondary carriage which supports the fastening heads 22 for vertical
movement.
The fastening heads 22, illustrated as comprising two parallel banks of
ultrasonic transducers, eight in each bank, are held in pairs in eight
clamping bars 98 extending forwardly from the cross beam 96, to which each
clamping bar is screwed. The lateral indexing movement of the fastener
heads 22, i.e., the sideward movement of the primary carriage 84 on the
primary track shafts 86, is effected by a double-acting air cylinder 100
(FIG. 1) which is secured in an anchor block on the upper cross beam 34
wih its piston rod connected by a suitable clevis or the like to a stud on
a clamp conveniently secured to one of the vertical track shafts 92 for
the secondary carriage.
The vertical movement of the ultrasonic fastening heads toward and away
from fastening cooperation with their associated anvils, i.e., the
vertical movement of the secondary carriage formed by the cross beam 96
and the slide bearings 94, is effected by a double-acting air cylinder 102
mounted on the subframe 90 of the primary carriage, with its piston rod
connected by suitable clevis or the like to the cross beam 96.
In the illustrated apparatus, employing a total of 16 ultrasonic fastening
heads 22, a separate ultrasonic frequency generator 104 is provided for
each fastening head, and the bank of ultrasonic generators is placed in
near proximity to the fastening heads 22 on a shelf 106 supported by the
frame standards above the upper cross beam 34 of the fixed frame. Each
ultrasonic generator 104 is, of course, suitably connected to a source of
power and to its associated transducer 22 by conductors which are not
illustrated except in the circuit diagram of FIG. 13. The fluid
connections to the several air cylinders likewise appear only in the
circuit diagram of FIG. 13.
The spring strip positioning mechanism 24, as earlier noted, is mounted on
the rectangular subframe 90 of the primary carriage of the indexing table.
It comprises a spring strip indexing bar 108 secured at its ends to the
piston rods of a pair of double-acting air cylinders 110, each clamped in
a mounting block secured to the vertical side members of the subframe 90
of the primary carriage 84 (FIG. 1). Arrayed along the indexing bar 108 is
a bank of U-shaped locator fingers 112 beneath which each new strip of
springs is inserted, and which serve to hold the individual springs of the
new strip in registry with those of its predecessor for the descent of the
fastener heads 22.
After each new strip of springs is connected to the assembly, the assembly
is indexed downwardly by the indexing bar 108, actuated by the air
cylinders 110 after the withdrawal from the assembly station of that bank
of anvils upon which the connections of the most recently added spring
strip were made. This indexing movement forces the newly-added spring
strip down upon the alternate bank of anvils, upon which the joining of
the next spring strip will be performed.
In that connection, it is now timely to observe, in FIG. 2A, that as each
new spring strip is added to the assembly by the connection of its
interspring webs to those of the preceding strip, each coil pocket is
rotated one-eighth turn from the strip axis, which tends to foreshorten
the new strip as its coils are drawn by the newly-made connections into
close association with those of the previous strip. The spacing of the
locator fingers 112 of the indexing bar is therefore preferably that of
adjacent anvils 20 of either bank of anvils, rather than the untensioned
two-coil spacing of the coils with the pocket-closing seams in line. For
purposes of good registry of the coils of successive strips in the
assembly, as well as for the sake of dimensional stability of the
completed construction, I prefer to maintain a slight tension in the
connected strips of the assembly such that when the indexing bar 108
descends and the locator fingers 112 push the newly-joined strip
downwardly toward the alternate anvils destined for use in the next cycle,
the springs which flank the alternate anvils are forced apart by the
intrusion of the upper surface of the anvil between them, and then snap
back audibly as their interconnecting web seats itself upon the anvil.
Conversely, by so spacing the coils of each new strip as to register with
those of the assembly, the newly-fed strip is essentially untensioned
before the interstrip connection is made. Therefore, to position the
interpocket web unerringly in registry with the anvil for the descent of
the fastening heads, each pair of fastening heads is provided with an
intervening pair of guide blades 114 which are secured to the clamping bar
98 which supports the associated pair of fastener heads so as to align
them in common with the anvils. The guide blades descend with fastener
heads 22, and by passing between the coils, force the interspring web down
onto that of the predecessor strip, while the thicker tips 50 of the
fastening heads enter the wider space between the diverging outlines of
the coils to weld the four thicknesses of pocket material together against
the anvil.
As the assembly 10 develops in size by the addition of successive strips 12
of springs, its downward progression from the assembly station 18 is
desirably guided by a delivery plate 116 of light sheet metal or the like
which may be secured at its upper edge to the underedge of the front plate
40 of the assembly station, and supported in a rearwardly bent curve by
arms 118 secured to the frame 16, so as to deliver the spring assembly to
a run-out table or the like.
When the assembly has reached the desired size, i.e., when the designated
last strip of springs is placed in the assembly station, the operator
severs the designated last strip from the supply (assuming a serpentine
lay-up), and initiates the final cycle, at the conclusion of which both
banks of anvils are in the assembly station. The operator then overrides
the program controller by a manual switch to withdraw the last-used bank
of anvils on which the asssembly is supported, and the assembly falls by
its own weight to clear the assembly station for the assembly of the next
construction.
To maintain good height alignment of the springs of the assembly, I find it
desirable to maintain the assembled springs in reasonable axial
confinement in the assembly station, and to provide for the axial registry
of the coils of each new strip with those of the prior strips. The desired
alignment is provided by an aligning bar 120 which spans the assembly
station from side to side, being secured at each end to one of two arms
122 pivoted on a common axis to brackets 123 secured to the subframe 90 of
the primary carriage of the indexing table. An overcenter spring 124
connected between one of the arms 122 and a switch-mounting bracket 126 on
the subframe 90 normally holds the aligning bar 120 aloft, while a switch
actuating cam 128 mounted coaxially with the same arm and pinned thereto
deflects the operating arm of a one-way switch 130 on the bracket 126 with
each stroke of the aligning bar 120, actuating the switch, however, only
on the up stroke.
Cycle Of Operation
At the beginning of each normal cycle, i.e., after the first two strips are
connected, both banks of anvils 20 extend into the assembly station with
one bank, say Bank A, in position to be engaged in fastening cooperation
by the ultrasonic fastening heads 22. The fastener heads 22 are poised
sufficiently well above the anvils 20 to accommodate two strips of
springs, and lower and last-joined strip being emplaced upon and suspended
from the anvils of Bank A, and the new strip resting upon it positioned in
coil-upon-coil registry therewith by the locator fingers 112 of the
indexing bar 108, and with the anvils of Bank B above the last-joined
strip and beneath the new strip (FIGS. 4 and 5).
Upon the initiation of the machine cycle by the raising of the aligning bar
122 by the operator, the ultrasonic fastening heads 22 descend en masse,
driven by the cylinder 102, first engaging the interpocket webs of the
upper strip of springs, forcing them into contact with the interpocket
webs of the registering lower strip, seating both webs firmly against the
Bank A anvils, and welding the two webs together (FIG. 6).
After the welding of the webs, the fastening heads 22 are retracted by the
cylinder 102, a blast of cooling air from the holes 52 of the Bank A
anvils lifts the welded interspring webs from the anvils, and the Bank A
anvils 20 are retracted en masse by their actuating cylinders 46.
The assembly is then forced downwardly by the indexing bar 108, powered by
its two actuating cylinders 110, to seat the interspring webs of
newly-joined row upon the Bank B anvils (FIG. 7). Each pair of springs
bracketed by the connections made on the anvils of Bank A straddles one of
the anvils of Bank B, being forced apart by the latter on their descent
and reclosing beneath the anvil as their interconnecting web is seated
upon it.
With the assembly indexed in the machine direction, the Bank A anvils are
reinserted, passing over the last-joined strip and into the crevices
between the two coils which flank the connections just made. The fastening
and positioning apparatus, viz., the overlying ultrasonic fastening heads
22 and the indexing bar 108, are then indexed laterally by one spring
diameter to stagger the line of connections of the new spring strip, which
is inserted by the operator beneath the locator fingers 112 and above the
re-inserted Bank A anvils. The operator then lowers the aligning bar 120
to locate the new spring strip in proper position, and then raises the bar
to re-initiate another cycle of operation of the machine, which is resumed
by the descent of the fastening heads 22 onto the anvils of Bank B.
At the beginning of each new spring assembly, one bank of anvils will have
remained in the station 18, either Bank A or Bank B, depending upon which
bank was used for the final weld for the previous assembly. In any event,
by manipulation of manual switches controlling the position of the two
banks of anvils, the operator positions the bank of anvils in the assembly
station which is compatable with the feeding direction of the first strip,
i.e., so that the first pair of spring coils from the assumedly continuous
supply straddles an anvil of the inserted bank, and withdraws the opposite
bank (FIG. 8).
The operator then seats all of the first strip upon the inserted anvils,
reinserts the previously withdrawn bank of anvils over the top of the
first strip, and racks the second strip of coils over the first, inserting
them beneath the locator fingers 112 of the assembly indexing bar (FIG.
9). The operator then lowers the aligning bar against the top strip, and
raises the bar to initiate the machine cycle earlier described.
When the desired number of strips has been joined, the supply strip is
severed and the bank of anvils which supported the assembly during the
final weld is withdrawn, the assembly descends from the assembly station
by its accumulated weight to make way for the beginning of its successor.
Control and Power Circuitry
The electrical and fluid circuitry for powering the operation of the
apparatus in accordance with the earlier described sequence of operations
is shown in FIG. 13.
The several air cylinders, all double-acting in nature, are gathered on the
righthand side of the diagram and are connected by appropriate supply
lines to a source of pressure air (not shown) through solenoid operated
valves arrayed in a line at the lower end of the electrical circuit
diagram on the lefthand side of FIGS. 13.
Thus, the cylinder 102 which lowers and raises the welding horns or
fastening heads 22 is controlled by a valve 132 which is biased to apply
pressure air to elevate the fastening heads, which are depressed only for
the relatively brief period during which the solenoid of the valve 132 is
energized. Similarly, in the case of the cylinders 110 which operate the
indexing bar 108 to advance the assembly after each new spring strip is
joined to it, the control valve 134 is likewise biased to raise the bar
108 to the elevated position illustrated in FIGS. 1, 2, and 4, the piston
rods of the cylinders 110 being extended only for the brief time that the
solenoid of the valve 134 is energized.
The cylinders 46 and 48, on the other hand, which govern the positions of
the front and rear banks of anvils, and which are required under certain
circumstances to maintain their positions of withdrawal or insertion, are
controlled respectively by the double-solenoid valves 136 and 138, each of
which is biased to a neutral, locking position as its "power off"
condition so as to maintain whatever position of the associated bank of
anvils was last dictated.
Similarly, the air cylinder 100 for the lateral indexing of the fastener
heads 22 and the coil positioning mechanism 24 is controlled by a
double-solenoid valve 140, the solenoids of which are energized
alternately on successive cycles of operation of the apparatus by a
mechanical latch relay 142.
The remaining air-operated functions, namely the blasts of cooling air
emitted from the blow holes 52 of the anvils, being momentary in
operation, are controlled by valves which are spring biased to the closed
position and opened only when their respective solenoids are energized,
the front bank cooling valve being 144 and the rear bank cooling valve
146.
The coordination of the position of the anvils and of the appropriate anvil
air blast with the lateral position of the fastening heads 22 is
determined by an air-powered, double-acting slave relay 148, whose
position agrees with that of the lateral indexing cylinder 100, and whose
electrical contacts are arranged so as normally to apply power only to one
set of the anvil-positioning air cylinders 46, or 48, at any one time.
That is, with the piston rod of the lateral indexing cylinder 100
retracted as indicated in FIG. 13, the piston of the relay cylinder 148 is
likewise retracted and its contacts closed to route power only to the
solenoids of the valve 136 which controls the position of the front anvils
of bank A so that while the fastening heads 22 are indexed to the right,
only those functions associated with the front bank of anvils are
operative, and those functions associated with the rear bank of anvils are
disabled.
Specifically, with the fastening heads 22 indexed right as seen in FIGS. 1,
8, and 9, the fastening heads descend upon the front bank A of anvils to
weld the two strips together, after which a cooling blast of air is
emitted only through the valve 146 and the front bank A of anvils to cool
those welds. The front anvils are then withdrawn and the assembly is
indexed by a momentary and reciprocal vertical movement of the indexing
bar 108, driven by the cylinders 48 through the control valve 134, after
which the front bank A of anvils is re-inserted, completing a single cycle
for the sealing of two spring strips together on the front bank of anvils
as described. During this cycle, the rear bank B of anvils remains
stationary in its normal position, i.e., inserted in the assembly station,
and as the final event of the cycle, the mechanical latch relay 142 is
energized momentarily to cause the lateral indexing valve 140 to shift the
fastening heads and indexing bar to the left by the extension of the
piston rod of cylinder 100, with the cylinder of the slave relay 148
following to position the relay switches to condition the circuit to
permit only the energization of the two valves controlling the position of
the rear bank of anvils, bank B, and to emit the cooling air through that
bank of anvils, i.e., to condition the apparatus for a new strip of coils
and a new cycle using the alternate bank of anvils.
The aforementioned operations of the solenoid-controlled air valves and of
the mechanical latch relay 142 a | | |
