Straight knitting machine

A straight knitting machine having two needle beds with knocking-over combs isposed in an inverted V-shaped configuration and a sliding carriage located above said needle beds is further provided with horizontal stop edges on said combs beneath the crossover zone of the needles associated with said needle beds for preventing the upward movement of the knitted piece upon activation of the needles. A pair of rotatable heads are mounted on a common support movable with said carriage with each head having a layering device mounted thereon and displaced 90.degree. from a stripping device and a hold down device which are also mounted on each rotatable head. The heads are rotatable at the end of each traversing movement of the carriage so as to locate the layering device and hold down device of one head in advance of the knitting zone and the layering device of the other head in trailing relation to the knitting zone during a subsequent pass of the carriage.

BACKGROUND OF THE INVENTION 
The present invention is directed to a straight knitting machine having two 
needle beds and knocking-over combs arranged in an inverted V-shape 
configuration for knitting without the application of takeoff tension on 
the knitted piece and devices to locate the stitches beneath the needle 
crossover zone with such devices being mounted on the sliding carriage for 
movement relative to the needle bed. 
In conventional straight knitting machines having two needle beds and 
knocking-down combs arranged in an inverted V-shaped configuration, a 
tension is applied to the knitted piece during knitting so that the 
stitches or loops depending from the needles slide on them under pressure. 
As a result of such tension, the previously knitted piece will not be 
pushed upwardly as the needles are advanced outwardly of the slots in the 
needle bed so that the tongues of the needles are properly opened and 
closed by the stitches or loops. After the stitches or loops are 
knocked-down over the closed needles, the newly formed row of stitches is 
pulled downwardly between the two needles beds by means of the tension on 
the previously knitted piece. The tension on the knitted piece is provided 
by take up rollers operatively located beneath the needle beds. 
The disadvantage of such straight knitting machines is that the tension on 
the center of the knitted piece is different from the tension on the edges 
of the knitted piece. Furthermore, it is not possible with such straight 
knitting machines to produce knit-goods where the knitting is not always 
effected over the entire width. Thus, it is not possible to save material 
or to knit the correct shape when simultaneously knitting individual 
knitted parts since, in this instance, groups of needles on the needle bed 
are not knitting for several rows or the stitches are popped off these 
needles. In order to permit this type of stitching, straight knitting 
machines were developed in which a wire, fastened to the sliding carriage, 
runs beneath the needle crossover zone to prevent the knitted piece which 
is not tensioned from being lifted above the knocking-over combs of the 
needle beds by means of the activated upwardly moving needles. Complicated 
devices are then required which swivel and turn and which are shifted, 
lifted and lowered at the end of each knitted row so that the wire will 
take the proper position for knitting the following row without additional 
lost motion of the sliding carriage. Furthermore, the hold down effect 
provided by such wire could only be achieved in the case of knitted pieces 
being produced simultaneously on both needle beds, that is, with double 
knitwear but not with the production of single knitwear. 
A straight knitting machine of the type described above is, for example, 
disclosed in German publication 1956190. In this machine, the stitches can 
only be held beneath the needle crossover zone with the passing of the 
sliding carriage by means of frictional contact. A device on the sliding 
carriage of the straight knitting machine is disclosed in German Utility 
Patent 7795391 which has a wire bracket acting as a stripping, holding and 
layering device with the passing of the sliding carriage. Separate 
stripping and holding devices are disclosed in Austrian Patent 214050. 
SUMMARY OF THE INVENTION 
The present invention provides a new and improved straight knitting machine 
having two needle beds and knocking-over combs arranged in an inverted 
V-shaped configuration which permits knitting of properly shaped one and 
two bed knitwear and particularly knitting of separate knitted pieces in a 
simple and accurate manne without the need for a takeup device. This is 
accomplished by the provision of stop means attached to the knocking-over 
combs which are located beneath the needle crossover zone to limit the 
upward movement of the previously formed rows of stitches. 
The sliding carriage is provided with a stripping device and a hold down 
device located in advance of the point of knitting, and it is further 
provided with a layering device which follows the point of knitting to 
place the newly formed stitches behind the stop means. Advantageously the 
stop means are formed by horizontal edges on the knocking-over combs 
located beneath the vertical knocking over edges of the combs. 
With such a straight knitting machine, it is possible to achieve in a very 
simple manner and with a minimum of technical complications single bed 
knitwear as well as two bed knitwear without the necessity for takeup 
tension on the knitted piece. The layering device places the newly formed 
rows of stitches behind the stops so as to prevent the knitted piece from 
being lifted upwardly as the needles are advanced. As a result, a 
differential tension across the width of the knitted piece does not occur. 
Additionally, in the case of double bed knitwear, the hold down device 
prevents the previously formed rows of stitches from being pulled away 
from the stop means due to the tension on the knitwear. 
The layering device according to the present invention is comprised of a 
spring bracket having an essentially horizontal part which pushes the 
knitwear downwardly and places the newly formed rows of stitches behind 
the stop means. The stripping device is comprised of a wire bracket and is 
arranged in such a manner that when the needles are driven out, the 
stripping device will slide along the lower edges of the needles. The hold 
down device is comprised of a spring wire arranged behind the stripping 
device in the direction of movement. The spring wire is provided with an 
essentially horizontal portion which holds the preceding rows of stitches 
behind the stops. The spring effect of the hold down device readily adapts 
the hold down device to the firmness of the knitwear. Advantageously, the 
layering device is disposed at a 90.degree. angle from the stripping 
device and hold down device upon a common rotatable head which can be 
rotated 90.degree. and locked in either position by means of a locking 
slide engageable in corresponding grooves of the rotatable head. The 
rotatable head is mounted on the supported which can be moved with the 
sliding carriage which moves over the needle beds. In order to permit 
optional knitting in both operating directions of the sliding carriage two 
rotatable heads are provided on the common support in association with 
each knitting system. 
The foregoing and other objects, features and advantages of the invention 
will be apparent from the following more particular description of the 
embodiment of the invention as illustrated in the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION 
The upper ends of two needle beds 1 and 2 are shown in FIG. 1 having 
knocking-over combs 3 and 4 associated therewith having essentially 
vertical knocking over edges 5 and 6. The knocking over combs 3 and 4 are 
further provided with stops 7 and 8 in the form of horizontal edges 
located beneath the vertical knocking over edges 5 and 6, respectively. 
Newly formed rows of stitches 9 are placed beneath the stops 7 and 8 by 
means of the layering device 10 which is comprised of a spring bracket or 
wire. The knocking over edges 5 and 6 prevent the knitwear previously 
produced from being lifted up when the needles are advanced. 
In FIG. 1, the row of stitches 9 of a single bed knit piece is shown held 
beneath the stops 7 by means of layering device 10 so that it cannot be 
lifted up. The hold down device 11, shown in FIGS. 2 and 3, is comprised 
of a spring wire which prevents the lifting up of the knitwear when the 
needles 13 are advanced. The needles 13 interact with a stripping device 
12 which is also comprised of a wire bracket during the knitting of double 
bed knitwear. 
The shapes of the layering device 10, the hold down device 11, and the 
stripping device 12 can be clearly seen in FIGS. 2 and 3. The layering 
device 10 is attached to one side of a rotatable head 15 which can be 
rotated 90.degree. about axle 14. A layering device 10a is attached to a 
second rotatable head 16 which is structured as a mirror image relative to 
the first head 16. Stripping device 12a and hold down device 11a are 
connected to a second side of rotatable head 15 which is disposed at an 
angle of 90.degree. relative to the first side. Likewise stripping device 
12 and hold down device 11 are attached to a second side of swivel head 16 
which is disposed at a 90.degree. angle relative to the side of the head 
upon which the layering device 10a is mounted. 
The rotatable head 15 is provided with grooves 17a and 18 which are adapted 
to receive a complementary end portion of a locking slide 19 which is 
slidably mounted on the support 20. Likewise, the rotatable head 15 is 
provided with grooves 17 and 18a which are adapted to receive the 
complementary end portion of locking slide 19a which is also mounted on 
the support 20. When the locking slides 19 or 19a are shifted upwardly as 
viewed in FIG. 2, the associated rotatable head will be unlocked for 
rotation from the position shown in FIG. 2 to the position shown in FIG. 
3. Downward movement of the locking slide will then lock the head in its 
new position. 
The rotatable heads 15 and 16 as shown in FIGS. 2 and 3 are rotatably 
mounted on axles 14 carried by a common support 20. The common support 20 
is moved, when required, over the needle beds 1, 2 along with the sliding 
carriage externally of the needle space of the machine. At the end of each 
passage of the carriage, the locking slides 19 and 19a are moved upwardly 
by any suitable means (not shown) and the rotatable heads 15 and 16 are 
rotated 90.degree. by switching means which are not shown. FIG. 2 shows 
the rotatable heads 15 and 16 in position for movement above the needle 
beds from left to right in the direction of the arrow A together with the 
sliding carriage which is not shown. In this instance, the layering device 
10 is rotated into operating position on the axle 14 in follow up to the 
knitting zone while the stripping device 12a and the hold down device 11a 
attached to the same rotatable head are out of operation. The stripping 
device 12 and the hold down device 11 which are attached to rotatable head 
16 are rotated into their operating position in advance of the knitting 
zone, while the layering device 10a on the rotatable head 16 is out of 
operation. 
FIG. 3 shows the positions of the rotatable heads 15 and 16 for sliding 
carriage movement from right to left, whereby the rotatable heads 15 and 
16 will move above the needle beds 1 and 2 in the direction of the arrow 
B. In this mode of operation, the stripping device 12a and the hold down 
device 11a are in operative position in advance of the knitting zone and 
the layering device 10a is in operative follow up position to the knitting 
zone. 
Each knitting system or zone is assigned a pair of rotatable heads 15 and 
16 and the shifting of the locking slides 19 and 19a as well as the 
rotation of the heads 15 and 15 are effected automatically through 
conventional means at the termination of each pass of the carriage at 
opposite sides of the knitting machine. 
While the invention has been particularly shown and described with 
reference to a preferred embodiment thereof, it will be understood by 
those in the art that varous changes in form and details may be made 
therein without departing from the spirit and scope of the invention.