Device for actuating movable cams in a flat knitting machine

A device for actuating movable cams for use on a flat knitting machine that includes several cams arranged on a cam plate, in which the cams are movable in a direction perpendicular to the plane of movement of the cam box, contains a drum having an axis of rotation that is perpendicular to the plane of movement of the cam box and that is located substantially central relative to all movable cams. The drum includes grooves in the peripheral portion thereof at axial distances from one another, which grooves have variable axial positions over the periphery of the drum. A corresponding engaging part rides in a respective groove and the drum is rotated by a drum mechanism through definite angular amounts so that cams are placed in or out of activity at a stroke of the engaging part in the groove by means of connecting bars assigned to each of the engaging parts riding in the grooves on the drum.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates generally to a device for actuating movable cams in 
a flat knitting machine and, more particularly, to a device for actuating 
movable cams in a flat knitting machine of the kind having a cam plate and 
several cams arranged thereon, which cams are movable in a direction 
substantially perpendicular to a plane of movement of the cam box. 
2. Description of the Background 
Flat knitting machines are known that have a cam plate and several cams 
arranged thereon, which cams are movable in a direction perpendicular to 
the plane of movement of the cam box. The cams are also movable 
perpendicularly to each of a number of grooves that are formed in a 
carrier and that cooperate with an engaging element, which run along such 
grooves. Each engaging element is mounted on a rod that is firmly attached 
to the respective cam involved, and the carrier is attached to a control 
shaft that is reversibly driven through predetermined angles. 
There are various actuating approaches already known for this kind of flat 
knitting machine and such actuating procedures are generally divided into 
the use of mechanical actuating means on the one hand and 
electro-mechanical actuating means on the other. In both cases, however, 
the cams of the cam box used for such actuation purposes are generally 
movable perpendicularly to the plane of movement of the needles in flat 
knitting machines. 
In the case of a purely mechanical device used to actuate the cams, the 
movement of the movable cams is brought about by fixed studs arranged at 
the machine end that operate upon the stroke reversal of the carriage, as 
it moves back and forth. In this fashion, the cams involved assume their 
desired positions by means of curved guides, which require expensive 
intermediate elements and other costly mechanical parts. 
In the case of electromechanical devices used for the actuating of cams, a 
distinction must be made between those which use electromagnetic 
correcting elements and those that make use of stepping motors and the 
like. Furthermore, it should be noted that electromechanical solutions 
present a further advantage in that they are particularly applicable for 
flat knitting machines of the kind that have a variable carriage stroke. 
In a system disclosed in German Patent Publication DE-OS No. 2,111,789, a 
separate electromagnet is installed for each movable cam. The 
electromagnet is arranged so that no forces result in the stroke direction 
of the electromagnet, in order to prevent the occurrence of unwanted 
disturbances to the knitting operation during operation of the machine. 
Another solution to the movable cams problem is disclosed in German Patent 
Publication DE-OS No. 2,622,347, in which the cams cooperate with a number 
of disks having cam-contoured grooves. The disks are jointly arranged on a 
control shaft, which can be rotated into predetermined angular positions 
by means of a stepping motor. The actuation of the cams is accomplished 
individually or in groups by rotating the control shaft in a manner that 
is predetermined by the corresponding camcontoured grooves. This system 
has a particular disadvantage in that it is not suitable for a large 
number of movable cams, both because of the mechanical expense due to the 
number of parts and also to the large physical space that is required by 
this large number of cams. The space problem is particularly problematic 
if the cams must lie close together in that knitting machine. 
OBJECTS AND SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present invention to provide a device 
for actuating movable cams in a flat knitting machine that can eliminate 
the above-noted defects inherent in the prior art. 
Another object of this invention is to provide a device for actuating cams 
in a flat knitting machine in which the actuation of a relatively large 
number of cams, which are arranged centrally in the cam box can be 
designed with a substantially dense packing arrangement. 
In accordance with an aspect of the present invention such device is 
provided that includes a drumshaped carrier on which grooves are formed on 
the peripheral surface thereof at an axial distance from one another and 
which have variable axial positions over the position of the drum. In this 
fashion, the axis of rotation of the drum is arranged perpendicularly to 
the plane of movement of the cam box and is located substantially 
centrally with respect to all movable cams. 
The above and another objects, features, and advantages of the present 
invention will become apparent from the following detailed description of 
illustrated embodiments thereof to be read in conjection with the 
accompanying drawings, in which like reference numerals represent the same 
or similar elements.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
In FIG. 1, a front cam plate 3 facing the needle bed of a cam box 1, as 
found in a flat knitting machine, is shown in top plan view. It is to this 
front cam plate 3 that the individual elements of the device for actuating 
the movable cams are attached. 
These cams are both firmly attached and movably arranged, that is, they are 
movable, and the cams in the currently common combined cam box 1 are both 
for knitting and stitch transfers. The cams are arranged symmetrically in 
cam box 1, with reference to a longitudinal unit plane 2. 
The cams 31, 32, 33, 34, 35, 36, are firmly attached to cam plate 3 and 
serve mainly as safety elements and also to form the different cam paths 
with the movable cams. The stitch cams 37, 37', for adjusting the stitch 
size, are movable parallel to the plane of movement of the needles. Stitch 
cams 37, 37', are arranged in cam box 1 in a known way and do not have any 
connection with the device provided by the present invention. Stitch cams 
37, 37' work independently of the elements provided by the present 
invention. 
Guard cams 38, 38' are movable both parallel and perpendicular to the plane 
of movement of the needles and as will be set forth below, these elements 
are connected with the device according to the present invention only in 
an indirect manner. 
In regard to a course direction A of a carriage, not shown in detail, on 
which cam box 1 is connected with cam plate 3, functional and structural 
distinctions are made among a rising cam 4, a first closing cam 5, a 
second closing cam 6, a protuberant cam 7, and a reception cam 8. It will 
be understood that corresponding cams 4', 5', 6', 7', and 8' are provided 
for the course moving in the opposite direction. 
Each of the above-mentioned movable cams is firmly attached to a 
respective, generally bar-shaped, guidance part 9, as shown in FIGS. 2 and 
3, that is arranged substantially perpendicularly to cam plate 3. An 
activation pin 11 engages in a respective one of a number of circular 
grooves 12 formed in drum 13, and pin 11 is located at an end 10 of 
increased dimensions arranged at one end of bar 9 that is provided for the 
respective cam involved. These movable cams can assume two precisely 
determined positions upon each passage of the cam box, that is, a working 
position in which the butts of knitting elements (not shown) can engage, 
and a nonworking position, in which the butts of such knitting elements 
cannot engage. 
A number of grooves 12 are arranged on the periphery of the drum 13 that is 
mounted for rotary motion on a cam plate 3 and that has its center 14 
located within the effective radius of the cams, as represented in FIG. 1, 
for example. Drum 13 is shown in FIG. 2 as mounted by ball bearings on a 
shaft 25 that is attached to a housing 24. Housing 24 also contains guides 
for bars 9 that bear the cams, and housing 24 is mounted on cam plate 3, 
as shown in FIG. 2. 
Referring now to FIG. 5, which is a development of the periphery of 
connection drum 13, grooves 12 are subdivided into tracks, which are 
located in several planes parallel to the axis of rotation 14 of drum 13. 
The movable cams are each assigned to a respective individual track in such 
a way that a corresponding activation pin 11 engages in the corresponding 
respective groove 12. In the embodiment shown herein, a total of ten cams 
are attached, which make use of a total of five paths or tracks 12 on 
connection drum 13. 
Turning back to FIG. 2, drum 13 is mounted to be rotated by a power 
transmission agent, which in this embodiment is a stepping motor 17, by 
means of inner gear rim 15 and a driving pinion 16, which is mounted on 
the drive shaft of stepping motor 17. By use of stepping motor 17 it is 
possible to shift drum 13 by definite and precise angular amounts. The 
active length of groove 12 for each cam amounts to an angular extent of 
144.degree. on the periphery of drum 13 and, in this embodiments, requires 
160 actuation steps of motor 17 to achieve the desired result. The axial 
formation of grooves 12 corresponds to stroke 30, that is, the extent of 
travel to be transmitted to the movable cam through pin 11, as represented 
in FIGS. 2 and 5. 
As shown in FIG. 2, to control the precise and correct angular position of 
drum 13, two control disks 18, 19 are attached at the upper end of drum 
13, and these disks 18, 19 are scanned without contact by proximity 
detectors or switches 20, 21, 22, 23. Proximity switches are attached to 
housing 24 by respective mounting brackets 48, 49, 50. These switches may 
be comprised of magnetic or optical detectors. The shape of the lower 
control disk is shown in FIG. 6 and includes two notches 26 and 27 in its 
periphery. Similarly, upper control disk 19 is shown in FIG. 7 and 
includes notches 28 and 29 in its periphery. The combination of these two 
disks 18, 19 make possible a definite recognition of different sector 
positions about drum 13. Each disk is divided in half by a diametric line 
and each half includes sectors designated as a, b, c, d, and e, so that in 
a given case for the three switches 20, 21, and 22 being arranged mutally 
separated by 90.degree. on the periphery of the disk, it is possible to 
recognize the desired sector. Notches 28 on the upper half of control disk 
19 cooperate with switch or detector 23 and aid in making the recognition 
of the precise position of drum 13 possible. 
The device for actuating movable cams in a flat knitting machine according 
to the present invention as described above operates as follows. Stepping 
motor 17 is activated at one of the stroke reversal points of the carriage 
that is moving back and forth, in which one or more cam boxes 1 that have 
movable cams is accommodated, whereby a number of rotary steps are 
performed in either a clockwise or counterclockwise position. More 
specifically, one rotary turning causes drum 13, which is connected to 
stepping motor 17 by means of gears 15, 16 to either place the attached 
means in or out of activity individually or in a certain combination, 
according to the specific design of grooves 12, arranged on the periphery 
of drum 13. It will be understood that the process described is also 
correspondingly repeated at the opposite stroke reversal point of the 
knitting carriage as it moves back and forth. 
For example, in position or sector c out of the five possible angle 
positions a, b, c, d, e of drum 13, cams 5, 5' are withdrawn out of 
activity, but on the other hand, cams 6, 6', 4, 4', 8, 8', and 7, 7' are 
lowered and are active. 
In position b of drum 13, cams 6, 6', 4, 4', 8 and 7' are withdrawn and 
cams 5, 5', 8' and 7 are lowered and are active. This causes the needles 
selected in direction of course A to reach cam path 42 with full-butt 
height to accomplish stitch transfer, but on the other hand, the needles 
selected with the half-butt height reach cam path 41 for stitch reception. 
At position d of drum 13, cams 6, 6', 4, 4', 8' and 7 are withdrawn and 
cams 5, 5', 8, and 7' are lowered, which leads the needles selected to 
reach cam path 42' with full-butt height for stitch transfer in direction 
of course A' but, on the other hand, the needles selected with half-butt 
height reach cam path 41' for stitch reception. 
Position a of connection drum 13 corresponds to position b, with the 
difference that protuberance cam 7' is also actuated for stitch transfer. 
Similarly, position e is the analog of position d. 
It must be understood that because a flat knitting machine with individual 
needle selection is involved in the above-described embodiment, so-called 
pressure cams 45, 46, 47 are also contained in the cam box. These cams 
serve to permit additional selection combinations, for example the tucking 
position of the needles. 
If adjacent cam boxes are equipped with more limited stitch transfer 
possibilities, and the number of movable cams is consequently smaller, it 
is possible to drive drums 13 of at least two cam boxes located one beside 
each other with a common stepping motor 17. This arrangement is shown in 
FIG. 8 in which it is seen that by use of drive connections 16, 51, 52, 
53, and 54 which are slip-less gear wheels and gear belts, that is, 
toothed timing belts that will not slip. Accordingly, this arrangement is 
sufficient to require control disks 18, 19 and proximity switches 20, 21, 
22, 23 on only one of the two drums, as shown in FIG. 8 on the drum at the 
left hand side of the drawing. 
The above description is given on a single preferred embodiment of the 
invention, but it will be apparent that many modifications and variations 
could be effected by one skilled in the art without departing from the 
spirit or scope of the novel concepts of the invention, which should be 
determined by the appended claims.