Note: Descriptions are shown in the official language in which they were submitted.
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SPECIFICATION
This invention relates to new and useful improvements
in wire knotting machines, and has particular reference to
a machine adapted to twist the end portion of a first wire
first about a second wire disposed at right angles to the
first, and then to twist the projecting end portion of the
first wire about its own standing portion to form a secure
connection between the wires. This connection, although
commonly denoted in the trade as a "knot", is not a knot
in the technical sense that a strand is led through a
loop or bight formed in itself.
The invention will be described in connection with its
use in the formation of a flat grid spring for upholstery
structures, although it will be readily apparent that its
use is not limited to this purpose. Flat grid springs
commonly consist of a pair of parallel longitudinal spring
side wires, with a continuous series of closely spaced
apart spring cross wires extending laterally between and
knotted at their ends about said side wires, and are
commonly formed by automatic machinery in which the side
wires are longitudinally advanced with an intermittent
motion, the cross wires being advanced longitudinally and
successively into position at a given station, cut to
proper length, and knotted about the side wires while the
side wires are at rest.
The described wire connection, or "knot", is not new
in and of itself, but heretofore the two twists involved
therein, the first of the cross wire around the side
wire, and the second of the cross wire about its own
standing portion, have been regarded as two separate
operations, each requiring its own set of wire-bending
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dies. ~lence the second twist could not be commenced
until the first was completed, and this fact essentially
doubled the time the side wires were required to remain
at rest while the knots were formed. The two separate
operations were deemed necessary since the two twists
must be formed in planes generally at right angles to
each other. This use of two twisting operations of course
severely limited the rate at which the cross wires could
be inserted and knotted, and hence limited the production
rate of the spring grid.
Accordingly, the primary object of the present inven-
tion is the provision of a wire knotting machine capable
of forming a knot of the type described with a single set
of dies, and with a single motion of a driver member,
whereby to form both the first and second twists in a
time no greater than has heretofore been required for the
formation of only the first twist. Generally, this
object is accomplished by the provision of a driver which
engages the end portion of a cross wire and turns it
around the side wire to form the first twist, and by
imposing a fixed anvil in the path of the cross wire end,
said anvil being configurated to guide the cross wire end
around its own standing portion, whereby the second twist
is formed during the final portion of the formation of
the first twist. An approximate doubling of the pro-
duction rate of the machine is thus permitted.
The machine as thus far described provides a knot
the second twist of which, that is, the bend of the cross
wire end about its own standing portion, is spaced apart
from the side wire, and in which the raw end of the cross
wire projects away from the cross wire in an exposed
position. This condition is permissable in some cases,
~such as when the resultant grid spring is to be completely
enclosed, but in some cases, such as when the spring is
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to be exposed in use, the raw wire ends could inflict
injury, snag upholstery fabrics, and the like. Accord-
ingly, another object of the invention is the provision
of means whereby each knot may be "finished" be pressing
the second bend of the cross wire, and its raw end, into
close proximity to the side wire, whereby the raw end is
shielded. This finishing operation, when its use is
desired, is performed at a station in the movement of the
side wires subsequent to that at which the knots are
initially formed, so that it can occur, with respect to
the knots of one cross wire, at the same time the knots
of the next subsequent wire are being initially formed.
In this manner, the finishing operation does not reduce
the production rate of the machine.
Other objects are simplicity and economy of structure,
and efficiency and dependability of operation.
With these objects in view, as well as other objects
which will appear in the course of the specification,
reference will be had to the accompanying drawing, wherein:
Fig. 1 is a side elevational view of a wire knotting
machine embodying the present invention, with parts
omitted and parts broken away,
Fig~ 2 is an enlarged, fragmentary sectional view
taken on line II-II of Fig. 1, showing the parts as
positioned at the commencement of the formation of a knot,
Fig. 3 is a fragmentary view similar to Fig. 2,
showing the parts as positioned at an intermediate stage
in the formation of a knot,
Fig. 4 is a view similar to Fig. 3, showing the parts
as positioned at a still more advanced stage in the
formation of a knot,
Fig. 5 is a fragmentary view similar to Fig. 4, showing
the parts as positioned at the completion of the formation
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of a knot,
Fig. 6 is a view similar to Fig. 5, showing the knot
only, separated from the machine,
Fig. 7 ls a fragmentary sectional view taken on line
VII-VII of Fig. 2,
Fig. 8 is a fragmentary sectional view taken on line
VIII-VIII of Fig. 4,
Fig. 9 is a fragmentary sectional view taken on line
IX-IX of Fig. 5,
Fig. lO is a fragmentar~ sectional view taken on line
X-X of Fig. 2,
Fig. ll is an enlarged fragmentary sectional view
taken on line XI-XI of Fig. 1 showing elements for per-
forming the knot "finishing" operation, prior to the
commencement of said operation.
Fig. 12 is a fragmentary view similar to Fig. ll,
showing the parts as positioned at the completion of the
knot "finishing" operation,
Fig. 13 is a fragmentary sectional view taken on line
XIII-XIII of Fig. 11,
Fig. 14 is a sectional view taken on line XIV-XIV of
Fig. 11,
Fig. 15 is a sectional view taken on line XV-XV of
Fig. 11,
Fig. 16 is a fragmentary sectional view taken on
line XVI-XVI of Fig. 11, and
Fig. 17 is a view similar to Fig. 12, showing the knot
only, separated from the machine.
Like reerence numerals apply to similar parts
throughout the several views. The grid spring to be
formed comprises a wire fabric including a pair of
parallel side wires 2 (one shown) and a series of closely
spaced apart parallel cross wires 4 extending transversely
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between said side wires and knotted at their ends about
said side wires by the machine forming the subject matter
of the present invention, which is indicated generally by
the numeral 6 in Fig. 1. Side wires 2 are usually each
provided with a sheath 8 (see Fig. 6) of twisted paper or
other soft, indentable material, and are often referred to
as "ropes" because of their resemblance thereto. Both the
side wires and the cross wires are formed of spring steel,
the side wires being relatively heavy and the cross wires
being relatively light. The grid is illustrated as being
formed in a horizontal plane. During the grid formation,
the side wires are transported longitudinally and con-
currently to the left as ~iewed in Fig. 1, in the direction
of arrow 10, which will be termed the "forward" direction.
They are advanced with an intermittent motion, the
distance between stops being equal to the desired spacing
between successive cross wires 4, by any suitable
mechanism, not shown as forming no intrinsic part of the
present invention, but well understood in the art. Each
time the side wires come to rest, a cross wire 4 is
knotted thereabout by the knotting machine 6. The knotting
machine shown is for forming the knots at the right side
wire 2, as viewed when facing forwardly, and it will be
understood that the knots at the left side wire are formed
by a similar but reversed machine.
Referring to Fig. 2, it will be seen that wire for
cross wires 4 may be fed from a reel source, not shown,
through a tubular guide 12 carried by a bracket 14
affixed to machine frame 16, by any suitable means, not
shown. The wire emerges from guide 12 at a distance out-
side of side wire 2 such as to provide a wire length
outside of the side wire sufficient to form the knot, then
passes transversely just below said side wire, then through
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through a guide 18 which starts in inwardly spaced
relation from right side wire 2 and extends to a similax
relation to the left side wire, to extend outwardly beneath
the left side wire at least as far as guide 12 is spaced
outwardly, from the right side wire. As detailed in Fig.
10, guide 18 consists of a fixed portion 20 and a
vertically movable portion 22, the portions normally
cooperating to form a tunnel 24 through which wire 4 may
be advanced. Movable portion 22 may be elevated upwardly
as indicated by arrow 26 in Fig. 10, whereby the holder is
opened and wire 4 may exit transversely forwardly from the
holder, as indicated by arrow 28, as will appear. Movable
guide portion 22 is lifted by a rod 30 (see Fig. 2) at the
proper times, as will appear.
As a first step in the knotting process, a wire
cutter blade 32 is actuated to sever the wire at the end
of guide 12, the normal position of the blade being shown
in Figs. 2 and 4, and its position, when actuated being
shown in Fig. 3. The portion o the cross wire outside
of the side wire will be denoted its "end portion" 4A,
and the portion thereof between the side wires will be
denoted its "standing portion" 4B.
Disposed just behind wire 4, between guides 12 and
18, is a driver member 34 constituting a tubular shaft
which is horizontal and extends forwardly and rearwardly
at right angles to wire 4, and through the central bore
of which side wire 2 is advanced to pass just above cross
wire 4. The rearward portion of the driver is carried
rotatably in a carrier 36, which in turn is mounted for
forward and rearward sliding movement in machine frame 16,
as by a sliding dovetail connection 38. Carrier 36 is
biased forwardly by a frame-based spring 40 (see Fig. 1)
to urge a transverse pin 42 thereof against a lever 44.
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Said lever is carried pivotally by machine frame 16, and
is pivotally driven with a reciprocal motion to cooperate
with spring 40 to move carrier 36 and driver 34 between a
forward position in which the forward end of the driver
substantially touches cross wire 4, and a rearward position
in which the forward end of the driver is spaced rearwardly
of wire 4 by a distance slightly greater than the diameter
of the cross wire. Driver 34 is turned oscillatably by a
pinion gear 46 (Fig. 1) fixed in its rearward end, which
is engaged by a gear segment 48 carried by an oscillatable
arm 50 which it will be understood is pivoted on machine
frame 16, and driven by means to be described, to oscillate
the driver through less than a full revolution. At its
forward end, driver 34 is provided with a forward exten-
sion 52, projecting approximately the diameter of wire 4,
and being eccentric to the driver axis and normally
projecting forwardly beneath wire 4, as in Fig. 1.
In the next step of the knotting process, driver 34
is turned in the direction of arrow 54 in Figs. 2 - 5, by
operation of gear members 46 - 48, just after wire 4 has
been severed by blade 32 as in Fig. 3. During this
turning of the driver, its extension 52 first engages end
portion 4A of wire 4, and bends it around side wire 2,
as indicated at 53, till it overlies standing portion 4B
of wire 4, as in Fig. 4. During this portion of +he driver
rotation, said driver is also retracted rearwardly against
spring 40 by lever 44, so that by the time the Fig. 4
position is reached, the free end portion 4A of the wire
will be disposed just behind standing portion 4B, as best
shown in Fig. 8. The leading edge of driver extension 52
is undercut as indicated at 56 in Fig. 1, and wire end 4A
rests in the undercut, to insure that it does not slip out
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of engagement with the extension during the turning and
rearward retraction of the driver. Thus, as the rotation
of driver 34 continues, to the position shown in Figs. 5
and 9, the extreme end portion of wire end 4A, which projects
outwardly from driver extension 52, is lead downwardly
behind standing wire portion 4B, and then formed to bend
forwardly and upwardly under wire portion 4B by an anvil
58.
Anvil 58 has the form of an upwardly projecting finger,
the upper end of which is at about at the level of sidè
wire 2, and is upwardly concave, as at 60, about an axis
of curvature at right angles to the side wire. Said
concavity extends from about the plane of the forward end
of the driver, forwardly beneath standing portion 4B of
the wire. Thus as wire end 4A is pressed forcibly down-
wardly against the anvil, it is forced to bend forwardly
beneath wire section 4B, as best shown in Fig. 9 to form
a hook bend 62 engaged below wire 4B. Referring to Figs.
1 and 2, it will be seen that the lower end of the finger
consistuting anvil 58 is connected to a bracket 64 by a
bolt 66 in a manner to permit vertical adjustment of the
anvil, and the bracket 64 is affixed to a second bracket
68 by a bolt 70 in a manner to permit adjustment of the
anvil transversely to side wire 2, so that the anvil may
be accurately adjusted depending on the wire diameter and
resilience, as well as other variable factors. It will be
understood that bracket 68 is affixed to machine frame 16.
When driver 34 reaches the position shown in Figs. 5
and 9, the knot is substantially complete, and the driver
is rotated to its original position in a direction opposite
to arrows 54 by its gears 46 - 48, ancl returned forwardly
by spring 40, preparatory to receiving the next cross wire
after side wires 2 have advanced forwardly one more step,
3~
guide 18 opening at this time to permit forward movement
of the knotted cross wire. Due to the resilience of the
cross wire, it will rebound from the Fig. 5 position when
released by the driver, recovering for example to the
position shown in Fig. 6, bringing hook 62 into engagement
with standing wire portion 4B, or nearly so. Although not
specifically illustrated, it will be understood that in a
manner well known in the machine art, the means for inter-
mittently advancing side wires 2, the means for advancing
cross wires 4 into position, the means for actuating wire
knife 32, the means for operating driver rotating gears
46 - 48, the means for operating driver retractor lever
44, and the means for operating lifter 30 to open and
close guide 18, are all accurately synchronized in order
that all of the described operations occur at the proper
moments. This may be done, for example, by driving all of
the enumerated devices from cams on a common cam shaft, so
that slight adjustments of the cams will properly syn-
chronize all functions. This is considered to be well
within the known scope of the art.
The operational speed of the machine is high. A
machine substantially as shown, except that it did not
include anvil 58 which is the principal feature of the
present invention, but formed the hook bend 62 by a
separate mechanical means which had to be actuated only
after bend 53 of the cross wire around the side wire was
completed and hence caused a delay, has been used for many
years and has consistently functioned to insert and knot
about 150 cross wires per minute, the precise rate
depending on the width of the insulator pad being formed,
since this factor determines the time required to shoot
the cross wires into position. However with the use of
anvil 58, which provides that both the bend 53 of the
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cross wire about the side wire, and also the formation of
hook 62, are accomplished in a single motion of driver 34,
provides a production rate of about 300 cross wires per
minute. This is an extremely important feature from the
viewpoint of production economy.
The knot formed as thus far described, and as shown in
Fig. 6, is a complete knot and provides a product which is
entirely satisfactory for many purposes, such for example
as when the product spring grid is to be totally enclosed
in an eventual upholstery structure. However, a knot of
this form does leave the cut raw ends of the cross wires
projecting and exposed, so that they could snag anything
they contact, thus doing damage or inflicting injury, and
thus would be objectionable in certain other uses, such
for example of when the spring grid, either bare or
plastic-coated, is to be exposed and used to support free
cushions or the like.
To overcome this possible disadvantage of the Fig. 6
knot, an optional knot "finisher" may be used, and is
shown in Figs. 11 - 17. The finisher comprises a pair of
cooperating die members consisting of an anvil finger 72
and a radial arm 74. Anvil finger 72 extends transversely
to side wire 2, at the level thereof, forwardly of the
position at which a cross wire 4 is being knotted about said
side wire, by a distance equal to the desired spacing
between successive cross wires. Said anvil finger over-
lies the side wire at its inner end portion, and is
affixed at its outer end, by a screw 76, to a bracket 78
which it will be understood is affixed to machine frame
16. Said anvil is provided at its lower side with a notch
80 through which side wire 2 may advance longitudinally.
Said notch provides a rounded corner 82 which when the
side wire is engaged therein, braces said wire against
upward or outward movement. The notch is enlarged at its
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forward end to present a forwardly facing shoulder 84,
intermediate its forward and rearward end, which
enlargement accommodates the bend 53 of the just pre-
viously knotted cross wire 4 about the side wire, with
shoulder 84 then bracing the bend of wire 4 against rear-
ward movement. Obviously, for the knot to pass through
the smaller portion of notch 80 to arrive at the described
position, the side wire must be deflected downwardly, and
for this purpose the lower rearward portion of the portion
of anvil finger 72 inwardly of said notch is bevelled
downwardly and forwardly at its lower rearward portion as
indicated at 86, and as best shown in Figs. 13 and 14.
As the side wire advances, cross wire 4 i~mediately
adjacent the side wire engages said bevel, and is
deflected downwardly, together with the side wire, until
just as the side wire comes to rest, it snaps upwardly to
engage the knot in the enlarged portion of notch 80, as
wire 4 snaps up in front of a forwardly facing shoulder 88
of the anvil. As wire 4 moves forwardly under bevel 86,
its extreme end portion at the cut end thereof, which
may extend above the standing portion 4B thereof as shown
in Fig. 11, is accommodated in a forwardly and rearwardly
extending groove 90 formed in the lower surface of the
anvil. The parts will then have the positions shown in
25 Figs. 11 and 13 - 16. The enlarged forward portion of
notch 80, and also shoulder 88, open through the forward
surface of the anvil finger, so that the wire knot may
emerge freely therefrom when the side wire next advances.
Arm 74 is affixed to and extends radially from a
horizontal shaft 92 parallel to the side wire in down-
wardly and outwardly spaced relation therefrom. Said
shaft is carried by bearings 94 which it will be under-
stood are affixed to machine frame 16. At the rearward
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end of said shaft, there is affixed thereto a crank 96
by means of which arm 74 may be angularly oscillated,
heing turned in one direction by said crank, and returned
in the opposite direction by a torsion spring 98
surrounding shaft 92, being anchored at one end in one of
bearings 94, and at its opposite end in the hub of arm 74.
Arm 74 is generally planar in a plane normal to side
wire 2, and its normal or "returned" position is best shown
in Fig. 11, with an edge surface 100 thereof confronting
the side wire, but spaced apart inwardly therefrom by such
a distance that the arm does not interfere with forward
movement of the side or cross wires. The rearward surface
102 of the arm is planar and vertical, and coplanar with
the shoulder 88 of the anvil finger, except that the
upper portion of the rear surface of said finger is cut
away, as indicated by shoulder 104 (see Fig. 13) to
provide a vertical surface 106 spaced apart from finger
shoulder 88 by a distance slightly greater than the
diameter of wire 4. Then, when arm 74 is turned by
operation of crank 96 from the position shown in Fig. 11
to that shown in Fig. 12, it embraces and traps standing
portion 4B of wire 4 between shoulder 88 of the finger
and surface 106 of the arm, and edge surface 100 of the
arm engages first the bend 62 of wire end 4A, and then
presses all of said wire end against the side wire, also
as shown in Fig. 12. This "finishes" the knot by moving
bend 62 of wire portion 4A, and also the raw cut end of
the wire, closely adjacent side wire 2, so that said raw
end is shielded, and is far less likely to snag layers
of upholstery cloth applied thereover, or to inflict
-injury. The wire end 4A rebounds resiliently to some
degree when released from between finger 72 and arm 74 by
the return of arm 74 to its Fig. 11 position, as shown in
- 13 -
Fig. 17. Also, the cut end of the wire may be pressed
into the sof-t sheath 8 of the side wire, for stiLl better
shielding. It will be understood that crank 96 is
powered from the same common cam shaft, or other common
drive means, as is driver 34 which initially forms the
knot, and with the means for advancing the side wires
intermittently, so as to remain properly synchronized
therewith.
The operation of the machine is believed to have been
adequately described in connection with the foregoing
description of its construction. It "knots" the wires at
a rate believed unattainable with any prior machine. The
primary feature contributing to this speed is of course
that a single turn of driver 34 both bends wire 4 around
side wire 2 and 53, and also forms bend 62 of wire end
portion 4A about standing portion 4B. EIeretofore it
has been considered necessary to make these two bends in
separate operations, thus slowing the production rate
of the machine. This improvement is accomplished
principally, as compared to previous machines, by removing
any previously used mechanism for forming bend 62, and
substituting therefore the specially formed anvil 58,
which functions to form bend 62 simultaneously with the
final portion of the bending movement of cross wire 4
around side wire 2. The increase of the production rate
of the machine thus provided is rather startling. The
knot "finishing" operation provided by finger 72 and arm
74 is of course a separate operation requiring a finite
time interval for its performance, but this does not slow
the production rate of the machine, since it is performed
at a separate station in the forward travel of the cross
wires, simultaneously with the initial formation of the
next following knot by driver 34. It should also be kept
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in mind that for many uses of the spring grid produced,
the finishing operation is neither required nor needed.
The knot finishing elements are therefore optional equip-
ment .
While we have shown and described a specific embodiment
of our invention, it will be readily apparent that many
minor changes of structure and operation could be made with-
out departing from the spirit of the invention.
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