FIELD OF THE INVENTION
[0001] The present invention relates to circular knitting machines and, more particularly,
to needle selecting apparatus therefor.
BACKGROUND OF THE INVENTION
[0002] Circular knitting machines conventionally include a rotating cylinder having vertical
grooves in the outer periphery in which knitting needles are slidably mounted for
movement between welt and knit positions or welt, tuck and knit positions. The spacing
of the grooves, and therefore the needles, around the periphery of the cylinder is
referred to as the "gauge" of the machine. Fine gauge circular knitting machines are
those having a gauge of 24 or higher.
[0003] Circular knitting machines typically are equipped with needle selecting apparatus
for selectively operating the needles to produce a predetermined pattern of knit stitches.
One form of a-multi-tier electrically controlled needle selecting apparatus is disclosed
in Japanese Publication No. 94619/1994 and an improved form thereof is disclosed in
United States Patent No. 5,823,015, both of which are assigned to the current applicant.
[0004] Such needle selecting apparatus include a spring jack movably mounted in each noodle
groove in the cylinder beneath the knitting needles for selectively raising the knitting
needles. These spring jacks are elastic and relatively narrow so that they can be
pushed inwardly and then spring back to their original position. In their original
position, the spring jacks will move their associated needles to the knit position.
Such spring jacks are disclosed in detail in United States Patent No. 5,647,230, also
owned by this applicant. A selector jack is mounted in association with each spring
jack and has a pattern butt thereon. These selector jacks are rockable radially of
the needle cylinder to push the spring jacks inwardly or to permit the spring jacks
to return to their original position. The selector jacks are operated by fingers activated
by piezoelectric elements to engage selectively the pattern butts on the selector
jacks in accordance with a pattern program in a controller.
[0005] With prior needle selecting apparatus heretofore Known, the range of selection is
such that such needle selecting apparatus is limited to coarser gauge circular knitting
machines or to fine gauge knitting machines operating at slower than desired speeds.
For example, as illustrated in Figure 11, a fine gauge knitting machine having a gauge
of 28 has a range of selection of only 1.57 mm (i.e. a width that stretches across
1.7 needles). Accordingly, there is a need for a needle selecting apparatus for fine
gauge circular knitting machines that will permit such machines to be operated at
faster speeds than has heretofore been possible.
[0006] Because the needle selecting apparatus is in large part mounted on the cam ring,
space is limited. Heretofore, the multi-tier electrically controlled needle selecting
apparatus has occupied so much of the available space that additional features, such
as an interlock jacquard apparatus, could not be employed.
SUMMARY OF THE INVENTION
[0007] With the foregoing in mind, it is an object of the present invention to provide a
needle selecting apparatus for a circular knitting machine which increases the range
of selection and therefore permits increased speeds in even fine gauge knitting machines
and which reduces the size of the needle selecting apparatus to permit additional
features to the employed for coarse gauge knitting machines.
[0008] This object of the present invention is accomplished by providing a needle selecting
apparatus which includes a pre-pusher cam which engages the selector jacks, before
the selector jacks are engaged by the fingers activated by the piezoelectric elements,
to move the selector jacks inwardly of the cylinder. Thereafter, in one embodiment,
the selector jacks for the selected needles are moved further inward by pattern fingers
to position the spring jacks for either the welt position or the tuck position of
the knitting needles. In another embodiment, the pre-pusher earn moves the selector
jacks to their innermost position and the pattern fingers engage and maintain the
selector jacks in that position for the desired interval. For coarse gauge knitting
machines, the pre-pusher cam permits the stack of piezoelectric elements and pattern
fingers to be reduced in number and therefore, the size of the needle selecting apparatus
is reduced and an interlock jacquard apparatus can also be provided.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] In order that the present invention may be more readily understood, reference will
now be made to the accompanying drawings, in which:-
Figure 1 is a fragmentary vertical section of the core part of a circular knitting
machine having the needle selecting apparatus of the present invention,
Figure 2 is an enlarged fragmentary elevational view of the needle selecting apparatus
of Figure 1 with the housing removed for clarity;
Figure 3 is a plan view of the piezoelectric elements of the needle selecting apparatus
of this invention;
Figure 4 is a plan view, partially in section, of the pre-pusher cams of the needle
selecting apparatus of this invention;
Figure 5 is a fragmentary elevational view of the cam shown in Figure 4;
Figure 6 is a fragmentary, schematic plan view of a number of the selector jacks,
a pattern finger, pre-pusher cam with a conventional pattern finger shown in phantom
lines;
Figure 7 is a view similar to Figure 6 of another embodiment of the present invention
with a modified pattern finger;
Figure 8 is a view similar to Figure 2 of a further embodiment of the present invention
in which an interlock jacquard apparatus is included;
Figure 9 is a fragmentary elevational view of the pre-pusher cam and interlock jacquard
apparatus illustrated in Figure 8;
Figure 10 is a plan view, partially in section, of the interlock jacquard apparatus
shown in Figures 8 and 9; and
Figure 11 is a view similar to Figures 6 and 7 of a conventional pattern finger and
selector jacks.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] The present invention now will be described more fully hereinafter with reference
to the accompanying drawings, in which preferred embodiments of the invention are
shown. This invention may, however, be embodied in many different forms and should
not be construed as limited to the embodiments set forth herein; rather, these embodiments
are provided so that this disclosure will be thorough and complete, and will fully
convey the scope of the invention to those skilled in the art. Like numbers refer
to like elements throughout.
[0011] Referring now more particularly to the drawings and particularly to Figure 1, there
is illustrated a circular knitting machine, generally indicated at
20, which includes a rotary cylinder
21 having a multiplicity of vertical grooves in the outer periphery thereof. A knitting
needle
22 is slidably mounted in each groove in cylinder
21 for vertical movement between either knit and welt positions or knit, tuck and welt
positions. A spring jack
23 is mounted in each groove in cylinder
21 beneath needle
22 for selectively raising the needles
22 from the welt position to the knit position or to the tuck and knit positions. A
selector jack
24 is mounted in each groove of cylinder
21 beneath each spring jack
23 and is pivotable about its lower end. Such spring jacks and selector jacks are described
with particularity in United States Patent No. 5,647,230 which is incorporated herein
by reference.
[0012] Each selector jack
24 has a first pattern butt
24a thereon and a second pattern butt
24b. The pattern butts
24a on the selector jacks
24 are at different locations along the length of the selector jacks
24 such that the pattern butts
24a on adjacent selector jacks
24 are not in alignment. Therefore, as cylinder
21 rotates, the pattern butts
24a travel vertically spaced paths of travel to make the pattern butts
24a accessible to a multi-tier electrically controlled needle selecting device, generally
indicated at
30.
[0013] Needle selecting device
30 includes a housing
31 mounted on a cam ring
25 of the knitting machine
20, and a vertical stack of spaced apart piezoelectric elements
32 (Figure 2). Piezoelectric elements
32 are mounted at one end
32a thereof on housing
31 in a cantilevered manner and have pattern fingers
33 carried by the other ends
32b thereof. Each piezoelectric element
32 is bifurcated and has two piezoelectric members
32c and
32d in parallel with separate pattern fingers
33a and
33b carried thereby. Piezoelectric elements
32 may be formed of bimorph-type ceramic elements or other piezoelectric materials that
will be known to persons skilled in this art.
[0014] Pattern fingers
33 are moved up or down by the piezoelectric elements
32 either into or out of the paths of travel of the pattern butts
24a. As illustrated in Figure 2, there are eight piezoelectric elements
32 in the stack and the arrangement of the selector jacks
24 is in sets of eight with the pattern butts
24a repeating in every set of eight selector jacks. When a positive voltage is applied
to piezoelectric elements
32, the pattern fingers
33 are moved upwardly out of the path of pattern butts
24a of selector jacks
24 and all of the needles
22 are moved to the knit position. When a negative voltage is applied to the piezoelectric
elements
32, piezoelectric member
32c will move to position its pattern finger
33a in the path of the pattern butt
24a of its selector jack
24 to cause needle
22 to move to the welt position while a negative voltage will cause piezoelectric member
32d to cause the selector jack
24 to cause its needle
22 to move to the tuck position.
[0015] Each pattern finger
33 has a cam portion
33c at its outer end (Figure 6) with an inwardly sloping surface
33d for moving the selector jack
24 inwardly to cause its needle
22 to move either to the welt or tuck position and a linear surface
33e parallel to the path of travel of the selector jacks
24 following the sloping surface
33d to maintain the selector jacks 24 in either the welt or tuck position until the spring
jack
23 is positioned at the appropriate cam track.
[0016] Needle selecting apparatus
30 includes a pre-pusher cam
34 slidably mounted in a mounting block
35 for movement between retracted (inactive) and extended (active) positions. Mounting
block
35 is in turn mounted on housing
31 above the stack of piezoelectric elements
32. A spring
36 biases pre-pusher cam
34 toward its retracted position and an actuating lever
37 is pivotally mounted on block
35 for moving the pre-pusher cam
34 from the retracted to the extended position.
[0017] Pre-pusher cam
34 has a first cam portion
34a that is positioned in advance or upstream of cam portion
33c on pattern finger
33a and a second cam portion
34b that is positioned in advance of cam portion
33c on pattern finger
33b. The first earn portion
34a engages pattern butts
24b and pushes the selector jacks
24 inwardly a partial distance before the selector jacks
24 are engaged by pattern finger
33a and moved further inward to cause the needles
22 to move to the welt position. The second cam portion
34b engages the pattern butts
24a and pushes the selector jacks
24 inwardly a partial distance before the selector jacks
24 are pushed further inward by pattern finger
33b to cause the needles
22 to move to the tuck position.
[0018] To place the present invention in proper perspective, Figure 11 illustrates the operation
of a typical needle selecting device having piezoelectric elements (not shown) and
pattern fingers
133 and selector jacks
124. The knitting machine represented is a fine gauge knitting machine of 28 gauge (having
a pitch of 0.907 mm) with eight selector jacks
124 in each set (i.e. based upon the spaced apart arrangement of the pattern butts on
the selector jacks). In this set, between the first selector jack
124y and the last selector jack
124z, the pattern fingers
133 have a range of selection of 1.57 mm (i.e. a width that stretches across 1.7 needles).
This narrow range of selection causes no problem with coarse gauge knitting machines
(i.e. less than 24 gauge), but in the fine gauge knitting machines, such as the 28
gauge illustrated, this narrow range of selection limits the speed of the knitting
machine.
[0019] Referring now to Figure 6, there is illustrated a similar 28 gauge knitting machine
20 in which the pattern finger
33a is shown in solid lines, the pre-pusher cam
34a is shown in dotted lines and the prior art pattern finger
133 is shown in phantom lines to illustrate their relative positions and mode of operation.
[0020] Prior to this invention, the pattern finger
133 had to push the selector jacks
124 inwardly between their outermost position (the knit position) to their innermost
position (the welt position) to effect the needle selection. Therefore, the cam surfaces
133e on the pattern fingers
133 were much longer and engaged the pattern butts of the selector jacks
124 earlier (Figures 6 and 11).
[0021] With the present invention, the pre-pusher cam
34 pushes the selector jacks
24 partially inwardly before the pattern fingers
33 engage the selector jacks
24 much later than was heretofore possible. Therefore, the range of selection, which
had been 1.57 mm (i.e. encompassing 1.7 needles), is now 4.10 mm (i.e. encompassing
4.5 needles) or 2.5 times that heretofore possible. This wider range of selection
makes it possible to increase the speed of the knitting machine to provide increased
production while still achieving proper needle selection.
[0022] Another advantage is that pattern finger
33 can be shorter and lighter than previous pattern fingers. Accordingly, pattern fingers
33 are more responsive.
[0023] Referring now to Figure 7, there is illustrated another embodiment of the present
invention in which like elements are referred to by like reference characters with
a prime notation added. A pattern finger
33' of a different configuration from that illustrated in Figure 6 is provided. Pattern
finger
33' has a very short inclined or sloping surface
33d' and a longer surface
33e' parallel to the path of travel of the selector jacks
24'.
[0024] In this embodiment, the pre-pusher cam
34' pushes the selector jacks
24' fully inwardly and the linear surface
33e' is the only part of pattern finger
33' that engages and acts on the selector jacks
24'. A range of selection of 3.23 mm (i.e. corresponding to 3.5 needles) is provided
and this range is twice the range provided by prior needle selecting devices. While
not as large as the range provided by the needle selecting device
30, this range is large enough to provide the margin for increased speed of the knitting
machine
20.
[0025] As previously stated, the present invention provides a range of selection with an
extra margin. This extra margin permits a reduction in the number of piezoelectric
elements in coarser gauge knitting machines which provides sufficient space for the
inclusion of an interlock jacquard device. Such an embodiment is illustrated in Figures
8-10, In which like elements are referred to by like reference characters with a double
prime notation added.
[0026] A multi-tier electrically controlled needle selecting device
30'' includes a vertical stack of piezoelectric elements
32'', pattern fingers
33'' and a pre-pusher cam
34'', all of which are as previously described. An interlock jacquard apparatus
40 is mounted in block
35'' so as to be slidable radially of the needle cylinder (not shown). Interlock jacquard
apparatus
40 includes first and second interlock pusher cams
41 and
42 mounted for radial sliding movement between retracted and extended positions and
which are biased toward the retracted (inactive) positions by springs
43 (only one of which is shown in Figure 10). Levers 37'' are pivotally mounted on block
35'' for moving the interlock pusher cams
41 and
42 from the retracted position to the extended or active position.
[0027] The interlock pusher cam 41 has an inwardly slanting or sloping surface
41a and a linear surface
41b. Interlock pusher cam
42 is of the same shape as is interlock pusher cam
41 and is therefore not shown specifically. The interlock pusher cams
41 and
42 engage additional pattern buns
24''d and
24''e on the selector jacks
24'' and on alternate selector jacks
24'', these pattern butts are at different heights from those on intervening selector
jacks
24''.
[0028] When activated, interlock pusher cam
41 engages the pattern butt
24''d on a selector jack
24'' and gradually pushes it partially inwardly. Then, interlock pusher cam
42 engages the pattern butt
24''e and pushes the selector jack
24'' further inward to its innermost position.
1. A needle selecting apparatus for a circular knitting machine including knitting needles
(22) movable between knit and non-knit positions, spring jacks (23) for moving the knitting needles (22) between such positions, selector jacks (24) for causing the spring jacks (23) to move the knitting needles (22) and a needle selecting device (30) for selecting and actuating the selector jacks (24) and including pattern fingers (33, 33', 33'') and actuating elements (32, 32''), characterized in that a pre-pusher cam (34, 34', 34'') is positioned to engage the selector jacks (24, 24', 24'') before such selector jacks (24, 24', 24'') are engaged by said pattern fingers (33, 33', 33'') and push said selector jacks (24, 24', 24'') inwardly and then the selector jacks (24) engage said pattern fingers (33, 33', 33'') whereby a wider or increased range of selection is achieved.
2. An apparatus according to Claim 1 wherein said pre-pusher cam (34, 34'') pushes said selector jacks (24, 24'') partially inward and said pattern fingers (33, 33'') push said selector jacks (24, 24'') further inward to their innermost position.
3. Art apparatus according to Claim 1 wherein said pre-pusher cam (34') pushes said selector jacks (24') to their innermost position and said pattern finger (33') engages and maintains said selector jacks (24') in said innermost position for a predetermined time interval.
4. An apparatus according to any of Claims 1-3 wherein said pre-pusher cam (34, 34', 34'') is internal of said needle selecting device (30).
5. An apparatus according to any of Claims 1-4 wherein said needle selecting device (30) is a multi-tier electrically controlled needle selecting device and wherein said
actuators (32, 32'') are piezoelectric elements (32, 32'').
6. An apparatus according to any of Claims 1-5 wherein said actuators (32, 32'') are a plurality of pairs of parallel piezoelectric members (32a, 32b) arranged in a vertical stack.
7. An apparatus according to any of Claims 1-6 wherein said pro-pusher cam (34, 34', 34'') includes first and second cam portions (34d, 34e, 34''d, 34''e).
8. An apparatus according to any of Claims 1-7 further including an interlock jacquard
apparatus (40).
9. An apparatus according to Claim 8 wherein said interlock jacquard apparatus (40) includes first and second interlock pusher cams (41, 42).