US 3729954 A
This invention relates to Rachel type warp knitting machines and particularly to an arrangement for controlling the guide bars thereof. Normal arrangements for this purpose comprise a number of jacks mounted in series with their operating rods coaxially arranged, so that the length of their strokes is additive. One of the end jacks is fixed by one of its parts to the knitting machine frame with the cylinders of the jacks being coaxially guided along the frame and a plurality of distributors is provided, each being associated with a corresponding jack and arranged to connect the jack to a source of fluid under pressure and to be controlled selectively in accordance with a pre-established program In accordance with this invention, the end jack opposite that end jack that is linked to the frame is securely attached to the heddle bar by one of its components and the piston rod of an end jack and intermediate jacks are securely attached to the cylinder of an adjacent jack passing into the cylinder thereof, in such a manner that its free end forms a stop for the end of the piston stroke of the associated adjacent jack: all the jacks are of the double-acting kind.
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Description (OCR text may contain errors)
United States Patent [191 Ducol [451 May 1, 1973  RACHEL TYPE LOOMS  Inventor: Jean-Paul Ducol, Bois DOingt,
France  Assignee: Centre Technique Industriel dit: In-
stitut De France, Boulogne S/Seine, France 221 Filed: May 18,1971
21 Appl.No.: 144,596
Primary Examiner-Ronald Feldbaum Att0rneyMas0n, Fenwick & Lawrence ABSTRACT This invention relates to Rachel type warp knitting machines and particularly to an arrangement for controlling the guide bars thereof. Nlormal arrangements for this purpose comprise a number of jacks mounted in series with their operating rods coaxially arranged, so that the length of their strokes is additive. One of the end jacks is fixed by one of its parts to the knitting machine frame with the cylinders of the jacks being coaxially guided along the frame and a plurality of distributors is provided, each being associated with a corresponding jack and arranged to connect the jack to a source of fluid under pressure and to be controlled selectively in accordance with a pre-established program In accordance with this invention, the end jack opposite that end jack that is linked to the frame is securely attached to the heddle bar by one of its com ponents and the piston rod of an end jack and intermediate jacks are securely attached to the cylinder of an adjacent jack passing into the cylinder thereof, in such a manner that its free end forms a stop for the end of the piston stroke of the associated adjacent I jack: all the jacks are of the double-acting kind.
9 Claims, 3 Drawing Figures RACHEL TYPE LOOMS The present invention relates to a control arrangement for guide or heddle bars of a knitting machine of the Rachel type, comprising a plurality of jacks forming a set and mounted in series one behind the other by their piston rods which are arranged coaxially, so that their strokes add up, said set of jacks, of which one of the end units is fixed by one of its component parts to the frame of the knitting machine, the cylinders of the jacks being mounted coaxially on the said frame, and a plurality of distributors each of which is associated with a corresponding jack and is able to link the said jack to a source of fluid under pressure and to be controlled selectively in dependence upon a pre-established program.
Such a control arrangement has already been described, for example in the Specification of French Pat. No. 1.235.754 or in the Specification of U.S. Pat. No. 3,089,322, both of which correspond to British Pat. No. 888,701. This known control device comprises two sets of jacks referred to as single-acting indexing jacks and is connected mechanically by means of a floating compensation bar and a lever which is held in contact, by one end with the center of said compensation bar and which, at its center, is hinged to the slide of a servo-control distributor and, at the other end, is hinged to the piston rod of a main single-acting jack, acting by means of a push button on a guide bar. The main jack is supplied with hydraulic fluid by means of the servo-control distributor and a timing distributor which is mounted between the said main jack and the servo-control distributor and which is, itself, controlled by means of an auxiliary distributor, the slide of which is controlled by a cam in dependence upon a preestablished program. A return spring applies the appropriate end of the lever to the compensation bar and moves the jacks of each set into their starting position from which the piston rods of these jacks are withdrawn.
During selectively positioning one or more of the pair of sets of jacks, the slide of the servo-control distributor is placed under the effect of the lever in a predetermined position in which the said servo-control distributor communicates with the timing distributor which itself establishes the link between the servo-control distributor and the main jack only after itself having been actuated by the auxiliary timing distributor. It is only after the establishment of this link that the rod of the main jack is displaced and draws along, in its movement, the heddle bar, the lever and the slide of the servo-control distributor which cuts the supply to the main jack when the desired position of the heddle bar is reached.
It will be readily understood that the known device is extremely complicated and necessitates the operation ofa large number of members, which do not contribute to the movement of the heddle bar, before the latter is moved. Moreover, this known construction brings about a relatively small and inaccurate control of the heddle bar which must, as is known, perform lateral movements equal to a division of needles or to a multiple of such a division.
In order to increase the speed at which the heddle bar is positioned, the pressure of the control fluid of the main jacks may be increased to overcome the large inertia inherent in the mass of the movable members of the main jack and of the heddle bar and members supported thereby. However, in this case, the piston rod of the main jack tends to continue its displacement once the supply to the main jack is cut so that the needles of the guide bar are placed momentarily in an incorrect or inaccurate position. Given that in the case of the known device, the main jack is of simple effect, each guide bar must be associated with a return spring which must be all the stronger as the speed of displacement of the guide bar increases, so that the control pressure of the main jack must not only overcome the inertia of the bar and the associated members but also the reaction of the return spring. Due to the existence of quite a strong return spring and the risk of exceeding the selected position for the guide bar, it has previously been necessary to use an incompressible hydraulic fluid as the control fluid despite the fact that a pneumatic fluid offers, from the point of view of speed and of control, great advantages. Moreover, the numerous joints provided in the mechanical link between the main jack and the units of said indexing jacks must be without play in order to avoid any additional source of inaccuracy in the selective positioning of the guide bar. The man skilled in the art knows that such plays occur inevitably after the machine has been operating a relatively short time.
It is an object of the invention to remove the aforementioned drawbacks: it is a further object to produce a control device of the type hereinabove referred to, which is capable of placing the guide bar in the selected position rapidly and accurately and] with the aid of simple component parts. According to the invention, the end jack opposite the end jack connected to the frame is securely attached to the guide bar by one of its movable component parts, the piston rod of an end jack and intermediate jacks being securely connected to the cylinder of an adjacent jack, passing into the cylinder of the adjacent jack, and forms, by its free end, a stroke end stop for the piston of the corresponding adjacent jack, and wherein all the jacks are of the double-acting kind.
As a result of this arrangement, the control of the guide bar is considerably simplified. Moreover, the force required for displacement of the guide bar and the speed of this displacement are determined in dependence upon the length of travel of the guide bar, i.e. in dependence upon the number of jacks supplied, the duration of total travel being substantially constant for all the positioning cycles of the said bar. Moreover, the accuracy of the positioning of the guide bar is greatly improved due to the different stops provided in the control jacks.
According to a first embodiment, "the end jack linked to the frame comprises a piston, the rod of which is securely attached to the said frame, whilst the other end jack is securely attached to the guide bar by a link rod which is fixed to the cylinder of the said end jack which passes into the latter and which forms, by its free end, an end of stroke stop for the movable piston of this end jack.
According to a second embodiment, the end jack linked to the frame comprises a link rod which is fixed, on the one hand, to the cylinder of the said jack and, on the other hand, to the frame, and which passes into the cylinder of this end jack and forms, by its free end, an
end of stroke stop for the piston of this end jack, whilst the other end jack is securely attached to the guide bar by means of its piston rod.
So as to be able to use jacks of same length, thus to reduce the stock of replacement parts necessary and easily to adapt the strokes of the different jacks to the changes in patterns and designs to be executed by the knitting machine of the Rachel type, the length of the free end of the link rod and of the free end of the piston rods, which free ends pass into the cylinder of the corresponding jacks, is adjustable.
In order to be able easily to adjust the length of stroke of the different jacks without it being necessary to dismantle them, the cylinders of each jack may comprise, on one of its ends, adjusting and locking means for the link rod or the piston rod of the adjacent jack, these means being accessible from the outside.
In order that the invention may be more clearly understood, reference will now be made to the accompanying drawings, which show some embodiments thereof by way of example, and in which:
FIG. 1 shows a diagrammatic comprehensive view of a control device according to the invention, intended, for example, for a Rachel knitting machine,
FIG. 2 shows a detailed section of one embodiment of a jack, and
FIG. 3 shows a diagrammatic comprehensive view of another arrangement of the set of jacks of a control device, according to the invention.
Referring now to the drawings, the device shown diagrammatically in FIG. 1 comprises a set of four pneumatic jacks A,B,C,D, arranged in series. To this end, in the example shown, the piston rod 1A of the first jack or upstream jack A is fixed to the frame 2 ofa Rachel knitting machine, whilst its cylinder 3A is mechanically attached to the piston rod 18 of the followingjack, also referred to as an intermediate jack B. In order to simplify the drawing of FIG. 1, it has been shown as being welded, but it will be apparent, with reference to FIG. 2, how it is preferred to be effected to enable adjustments of the length of the part of the rod passing into a jack. Moreover, the cylinder 38 of the first intermediate jack B is securely attached to the rod 1C of the second intermediate jack C and so on, the cylinder 3D of the fourth jack forming, in this embodiment the downstream jack D, being securely attached to a link rod 4 which links it to the heddle bar (not shown) which it is arranged to control.
Each jack A to D is a double-acting jack and is axially mounted in the frame 2 by means ofits corresponding cylinder 3A to 3D. It thus comprises two ports which have flexible pipe lines 5A to 5D and 6A to 6D linked to associated electro-magnetically operated distributors 7A to 7D. So as not to complicate the drawing, the details of these distributors have not been shown, but they may be of any suitable type; for example, they may have a cylindrical slide driven in one direction by an electro-magnet and in the other by a return spring. Naturally, the flexible link pipes 5A to 5D and 6A to 6D must be fitted in a manner as to accommodate the largest attitudes or strokes envisaged for the jacks. All the distributors 7A to 7D are supplied from the same source of compressed air.
It will be noted in FIG. 1 that the piston rod EB, lC,lD of each of the jacks B,C or D respectively, is extended within the preceding adjacent jack A,B or C in a manner to form an end of stroke stop, limiting the relative displacement of the piston working in the same jack as the said stop. The same applies for the link rod 4 and the cylinder SD of the downstream jack D. The links between the different jacks A to D are arranged in such a manner that the stroke of the upstream jack A corresponding to a stroke or attitude of displacement equal to one division of needles, that of the first intermediate jack B to twice such division, that of the jack C to 4 times and, finally, that of the jack D to 8 times one division of needles. It is understood that under these conditions, by selectively exciting the four distributors 7A to 7D, strokes of the guide bar equal to any number of divisions between 1 and 15 can be produced.
Referring to FIG. 1, the selective control of the distributors 7A to 7B is effected as follows: the energizing electro-magnet of each distributor, such as 7A, is linked to a common line 8 by means of a contact 8A,8B,8C or SD of a relay 9A,9B,9C or 9D. The line 8 is in turn connected to a suitable current source 10 by means of a synchronization contact 11 operated by a cam 12, itself operated by the mechanism of the loom, so as to close the said contact 1 1 during the time which the guide bar is to occupy a definite position during the operating cycle (angle a). As regards the coil of the relay 9A in question, this is supplied by the output from an individual amplifier 13A, whose input of which is linked to an associated photoelectric cell 14A. The four cells 14A to 14D are arranged in a row opposite a code or programme carrier 15, such as a suitable photographic film behind which a light source 16 is located. The film 15 comprises four strips, each of which comprises opaque and transparent zones arranged in succession one behind the other in dependence upon the displacements to be effected by the guide bar, i.e. the pattern to be produced on the textile product.
It is understood that, when a strip of the film 15, associated with one photoelectric cell, for example to the cell 14A, comprises a transparent zone, the light from the source 16 excites this cell and thus sets up a signal. The latter is amplified at 13A and controls the energization of the coil of the relay 9A which thus closes the contact 8A. If, at the same time, the synchronization contact 11 is closed by the cam 12, the current from the source 10 is applied to the distributor 7A and, consequently, the jack A is operated to cause its cylinder 3A to advance towards the left of FIG. 1 for a maximum stroke determined by the amount that the piston rod 18 is moved, i.e. by the position of the free end of this rod 18 within this cylinder 3A, the free end of this rod 18 acting as a stop. The other cells 14B, 14C, 14D
operate in a similar manner, and it will be understood that it is possible to establish with film having four strips 15, a control of the guide bar in dependence upon the desired pattern for the textile article to be produced. It will be noted that in the diagrammatic representation of FIG. 1, all the jacks are shown in the expanded position.
It will be noted that, in order to arrange the contact, for example 8A of the corresponding relay for example 9A, it is advantageous that the relays 9A to 9D operate a little before the cam 12 itself closes the synchronization contact 11. Moreover, it is understood furthermore that the rest position of the jacks (i.e. that corresponding to the non-energization of their individual distributors) may correspond, either to the contraction (the stops provided on the piston rods and on the link rod) or, on the other hand, to expansion (Le. in the position shown on FIG. 1). It is sufficient to programme the film to suit. Furthermore, it will be noted, finally, that the relays such as 9A act like an AND gate in an electronic circuit. Thus, they could possibly be replaced by such gates, provided that they are arranged to deliver sufficient signal strength for operation of the electro-magnetic distributors. Finally, the position of the jacks as shown on FIG. 1 may be reversed, the piston rods 1A to 1B being directed to the left and not the right, and the first jack A having its cylinder 3A attached to the frame 2 by means of the link rod 4 and the piston rod 1B is thus directly connected to the guide bar as shown in FIG. 3.
FIG. 2 shows the detail of one preferred embodiment of ajack, for example the jack A. The rod 1B of the following jack B is not welded to the end of the cylinder 3A of the jack in question, but is simply locked in position by a split conical socket system 17A and locking cone 18A screwed onto the threaded sleeve 19A which rigidly connects the socket 17A to the adjacent base of the cylinder 3A. Such a device enables the amplitude of the stroke of the jack to be adjusted as desired and to adapt it, consequently, to the division of needles (gauge) when this is necessary, for example during a change in the division of needles. The piston 20A of the jack comprises a sealing gasket 21A as well as a sleeve 22A which is attached to the cylinder 3A and wherein the rod 1A of the piston 20A slides (see sealing joint 23A). Naturally, the sleeve 19A also comprises a sealing joint 25A.
It will be understood that the invention enables a positive control device to be produced, of great power, small size, great accuracy and by means of which it is possible to move a guide bar according to any pre-arranged program. The code or programme carrier formed by the film 15 may be of very small size and its installation does not pose any particular problem.
It must, moreover, be understood that the description has been described only by way of example and that various modifications may be made to the details set forth without in any way departing from its scope as defined by the appended claims.
1. In a control arrangement for the guide bar of a warp knitting machine of the Rachel type type, comprising a set of double acting jacks including two end jacks and at least one intermediate jack all coaxially disposed one behind the other and guided by their cylinders in the frame of said knitting machine, one of the said end jacks being linked by one ofits component parts to said frame whilst the other end jack is fixed on the one hand by its cylinder to said guide bar and on the other hand by his piston rod to the adjacent intermediate jack which in his turn is fixed, by his piston rod to the cylinder of another adjacent intermediate jack or of said one end jack so that the jack strokes add up, and also comprising a source of fluid under pressure and a set of fluid distributors each of which is associated with LII a corresponding jack and is adapted to link the said jack to said source and to be controlled selectivelyjndependence upon a pre-established program, the imthe said other end jack, which passes into said latter and whose free end forms an end stop for the stroke of the movable piston of said other end jack.
3. A control device according to claim 1, wherein said one end jack connected to said frame comprises a link rod which is fixed to the cylinder of the said one jack and also to said frame and passes into said cylinder of said one end jack and whose free end forms an end stop for the stroke of the piston of said one end jack, whilst said other end jack is securely attached to said guide bar by means of its piston rod.
4. A control device according to claim 1, wherein the length of the free end of the piston rod that passes into the cylinder of the adjacent jack is adjustable.
5. A control device according to claim 2, wherein the free end of said link rod that passes: into the cylinder of said other end jack, is adjustable.
6. A control device according to claim 3, wherein the free end of said link rod that passes into the cylinder of said one end jack, is adjustable.
7. A control device according to claim 2, wherein the cylinder of said other end jack includes adjusting and locking means for said link rod of the adjacent jack.
8. A control device according to claim 1, wherein the cylinder of one of the end jacks and of each intermediate jack includes adjusting and locking means for said piston rod of said adjacent jack.
9. In a control arrangement for the guide bars of a knitting machine of the Rachel type, comprising a plurality of jacks forming a set and mounted in series one behind the other with their operating rods coaxially arranged so that their strokes add up, said sets of jacks of which one of the end jacks is fixed by one of its component parts to the frame of the knitting machine, the cylinders of the jacks being coaxially guided over the said frame, and a plurality of distributors each of which is associated with a corresponding jack and is adapted to link the said jack to a source of fluid under pressure and to be controlled selectively in dependence upon a pre-established program, the improvement which consists in that the end jack opposite the end jack that is linked to said frame, is securely attached to the guide bar by one of its movable component parts, the piston rod of an end jack andintermediate jacks being securely attached to the cylinder of an adjacent jack passing into the cylinder of the adjacent jack and its free end forming an end of stroke stop for the piston of the associated adjacent jack, and wherein all of the jacks are of the double-acting kind.