GB2029867A

GB2029867A - Single needle selection device for flat knitting machines

Info

Publication number: GB2029867A
Application number: GB7922892A
Authority: GB
Original assignee: Atelier de Construction Steiger SA
Current assignee: Atelier de Construction Steiger SA
Priority date: 1978-09-12
Filing date: 1979-07-02
Publication date: 1980-03-26
Also published as: FR2436207B1; JPS5540897A; IT7925060A0; FR2436207A1; CH632024A5; GB2029867B; DE2926574C2; JPS6250590B2; DE2926574A1; IT1122477B; ES484075A1

Abstract

In a flat knitting machine, each needle 7 in needle bed 1 is selected to knit by being pushed leftwards as shown Fig. 3 by movement of push-rod 8 when its foot 9, in a raised working position engages a cam groove 14 on a carriage traversing the machine. Each push-rod 8 is engaged by auxiliary push-rod 10 provided with feet 11 and 12 in bed 2. As the carriage passes, firstly a cam 15 thereon acts on foot 12 to depress push-rod 10 which lowers push-rod 8 and foot 9 to a lower working position below cam groove 14. Depression of push-rod 10 causes foot 11 to displace a pawl 17 axially rightwards against a spring. This pawl movement pivots the lever near to an electromagnet which, if energised, holds the lever to lock the displaced pawl 17 so it cannot prevent push- rod 10 rising under action of spring 23 when cam 15 has passed. Foot 9 is thus lifted to the raised working position to be moved leftward by cam groove 14. If the electromagnet is not energised, pawl 17 is returned by its spring leftwards to engage above foot 11 and so hold down push-rod 10. Thus foot 9 remains in the lower working position and is not moved by the cam groove 14. <IMAGE>

Description

SPECIFICATION Single needle selection device for flat knitting machines This invention concerns single needle selection devices for flat knitting machines.

In a known single needle selection device for flat knitting machines such as described in German Patent No. 24031 two magnets which complement each other are respectively provided on the movable cam carriage, for controlling each auxiliary push-rod. These magnets are constructed as working magnets and for releasing the auxiliary push-rod tilt a lever which has a fixed mounting and normally locks the auxiliary push-rod. In this case, the lever locking a selected auxiliary push-rod is tilted from a spring-loaded inoperative position against this spring action into a working position releasing the auxiliary pushrod.Therefore, lifting or pushing magnets of this type which carry out mechanical work must have a certain minimum efficiency and must be constructed to be correspondingly strong and are therefore large, which requires both a correspondingly large space to contain them and a relatively high consumption of current. Also, these magnets operate comparatively slowly, because as they operate not only is it necessary to overcome the inertia of the lever which is stationary, but also the force of its return spring.

An object of the invention is to provide a selection device which can have fewer control magnets which may also be weaker and thus smaller so that a correspondingly smaller space for them is required and smaller current consuption is necessary for their activity, and higher operating speed may be achieved.

According to the invention there is provided a single needle selection device for flat knitting machines, in which a carriage travels to and fro with a cam arrangement and needle selection heads above needle beds to actuate auxiliary push-rods associated with each needle and controlled by electromagnets, which auxiliary push-rods each raise a corresponding needle push-rod when a corresponding needle is selected and push a foot of the needle push-rod into the path of movement of the cam arrangement, comprising a pawl in a working position (in which the pawl is pushed by a first spring when a said control magnet is not excited) locks its corresponding auxiliary push-rod in a position pushed downwards against action of a second spring by a second cam arrangement upon the passage of the carriage and thus keeps the foot of the needle push-rod outside the path of movement of the first mentioned cam arrangement, and which pawl in another working position (in which the pawl is displaced against the action of the second spring by the auxiliary push-rod as the auxiliary push-rod is pushed downwards) is locked when the said control magnet is ecited so that the auxiliary push-rod is once more raised under the action of the second spring after the passage of the second cam arrangement and brings the foot of the needle pushrod into the path of movement of the first cam arrangement for actuating the selected needle.

Such a selection device can be constructed so that the electromagnets acting as control members act as simple holding magnets, which are not required to produce any mechanical movement and can be kept correspondingly small and thus space-saving and energy-saving. The mechanical work for selecting the needle and actuating the auxiliary push-rod is on the contrary performed by the carriage as it passes, in that the second cam arrangement shifts all the auxiliary push-rods one after the other into an inoperative position where each is either locked by the corresponding pawl urged by the first spring, when the control magnet is not excited, or when the control magnet is excited and the pawl is thus locked, the auxiliary push-rod returns to its initial position under the pressure of the second spring after the passage of the carriage, in which initial position the foot of the corresponding needle push-rod is brought into the path of movement of the first cam arrangement and the selected needle is actuated.

Preferably the or each pawl is movable axially of the pawl, a pivotally mounted tilting lever is associated with the or each pawl, one arm of the lever is held stationary by the control magnet when the latter is excited, another arm of the lever is arranged to engage in a recess of the pawl to prevent the pawl from moving axially, and said lever being freely pivotably, when the control magnet is not excited, to allow an axial movement of the pawl under the action of the first spring for locking its corresponding auxiliary push-rod.

Due to this arrangement of the pawl(s) using a tilting lever or levers operating virtually without inertia, the construction of the selection device allows a higher knitting speed and thus higher productivity combined with a troublefree and reliable method of operation.

If desired a wire can extend at right-angles over all the needle push-rods, the arrangement being such that by engagement of a said push-rod foot with said wire, a desired needle push-rod and the respective auxiliary push-rod can be put out of operation easily.

The invention will now be further described by way of example with reference to the accompanying drawings in which: Figure 1 is a diagrammatic front view in the direction of movement of the carriage of a fragment of a flat knitting machine provided with a single needle selection device formed according to the invention; Figure 2 is a fragmentary side view, at right-angles to the direction of movement of the carriage of the machine in Fig. 1; Figure 3 is an enlarged diagrammatic section of a fragment of the machine in Fig. 1; Figure 4 is a diagrammatic illustration of the actuation of an auxiliary push-rod by the carriage; Figure 5 is an enlarged cross section of a fragment of the pawl system actually used in the machine in Fig. 3, and; Figure 6 is an illustration of the first cam arrangement selecting a said needle push-rod.

With reference to the drawings, the needle selection device has needle beds 1 arranged in a conventional normal position and second needle beds 2 vertically below the first needle beds at the lower ends thereof. A carriage 4 with cam plates 5 and needle selection heads 6 travels on rails 3 over the needle beds 1 and 2.

Located in the needle beds 1 are a plurality of knitting needles and corresponding needle push-rods with feet as exemplified in Fig. 3 by a knitting needle 7 and a needle push-rod 8 with a foot 9. Located in the needle beds 2 are a plurality of auxiliary push-rods with feet as exemplified in Fig. 3 by an auxiliary pushrod 10 with feet 11 and 12. The rear end of the needle push-rod 8 engages in a recess 1 3 in the auxiliary push-rod 10. A cam part 1 4 is located above the foot 9 of the needle pushrod and cam parts 1 5 and 1 6 travel over the foot 1 2 of the auxiliary push-rod.

A pawl 1 7 is located opposite the so-called selection foot 11 of the auxiliary push-rod, which pawl is urged axially by a spring 1 8 (Fig. 5). When the pawl moves leftwards in Fig. 5 in response to thrust of the spring 18, a tilting lever 20, engaged in a recess 1 9 in the pawl, is tilted about pivot point 21 and thus separates one arm of the lever from a holding magnet 22.

The auxiliary push-rod 10 is under the action of a compression spring 23.

It is possible to use a single or multi-pawl system according to the division of needles.

The method of operation is as follows: The cariage 4 moves with its cam plates 5 and needle selection heads 6 over the needle beds 1 and 2. Thus, all the auxiliary pushrods 10 are pushed downwards one after the other by the cam part 1 5 striking against the foot 1 2 of the auxiliary push-rods. In this case, the pawl 1 7 is moved outwards (rightwards in Fig. 5) against the action of its spring 18 and the lower arm of the tilting lever 20 is pivoted against the holding magnet 22.

If current is supplied to the magnet, then the lower arm of the tilting lever is held and the pawl is locked in its outermost working position, whereas after the passage of the cam part 15, the auxiliary push-rod 10 once more slides upwards under the pressure of its spring 23. The needle push-rod 8 is thus raised and its foot 9 comes into the region of the cam part 14, by which it is engaged and moved forwards. The needle 7 is thus moved into the region of further knitting cam parts.

On the other hand, if no current is supplied to the magnet, under the action of its spring 18, the pawl returns inwards (leftwards in Fig.

5) and locks the auxiliary push-rod 10 in the lower working position of the auxiliary pushrod by abutting behind its selection foot 11.

The needle push-rod 8 consequently likewise remains lowered and its foot 9 is not engaged by the cam part 14. The foot 9 accordingly remains in this working position outside the range of action of the knitting cam part and the respective needle is not actuated.

The cam part 1 6 serves for the reliable separation of the two working positions of the foot 9.

With a plurality of fine needles disposed close together the magnets are located one above the other in a vertical plane (Fig. 3) and the corresponding selection feet 11 on the individual auxiliary push-rods 10 are staggered with respect to each other at different heights. Fig. 3 only shows the front auxiliary push-rod 10 completely whereas the other auxiliary push-rods are located therebehind and differ only in that their selection feet are located at different heights. In this way, when fine knitting needles are used, a plurality of push-rod and needle units together with their control units can be located in a small space, which is a considerable practical advantage.

The construction in the drawings also allows certain needle push-rods to the put out of operation easily. For this, the respective needle push-rod 8 (Fig. 3) is pushed downwards and thus pulled rearwards, i.e. in the illustration in Fig. 3, towards the right, so that the foot 9 of the push-rod engages an under side of a wire 24 which, under tension, extends at right-angles above all the needle push-rods. In this way, the auxiliary push-rod 10 remains outside the range of action of the cam part 15 and the pawl 17.

Claims

1. A single needle selection device for flat knitting machines, in which a carriage travels to and fro with a cam arrangement and needle selection heads above needle beds to actuate auxiliary push-rods associated with each needle and controlled by electromagnets, which auxiliary push-rods each raise a corresponding needle push-rod when a corresponding needle is selected and push a foot of the needle push-rod into the path of movement of the cam arrangement, comprising a pawl associated with each auxiliary push-rod, which pawl in a working position (in which the pawl is pushed by a first spring when a said control magnet is not excited) locks its corresponding auxiliary push-rod in a position pushed downwards against action of a second spring by a second cam arrangement upon the passage of the carriage and thus keeps the foot of the needle push-rod outside the path of movement of the first mentioned cam arrangement and which pawl in another working position (in which the pawl is displaced against the action of the second spring by the auxiliary push-rod as the auxiliary push-rod is pushed downwards) is locked when the said control magnet is excited, so that the auxiliary pushrod is once more raised under the action of the second spring after the passage of the second cam arrangement and brings the foot of the needle push-rod into the path of movement of the first cam arrangement for actuating the selected needle.

2. A device as claimed in claim 1 in which the or each pawl is movable axially of the pawl, a pivotally mounted tilting lever is associated with the or each pawl, one arm of the lever is held stationary by the control magnet when the latter is excited, another arm of the lever is arranged to engage in a recess of the pawl to prevent the pawl from moving axially, and said lever being freely pivotable when the control magnet is not excited, to allow an axial movement of the pawl under the action of the first spring for locking its corresponding auxiliary push-rod.

3. A device as claimed in claim 1 in which a number of said pawls are arranged one above the other in a vertical plane, and the auxiliary push-rods corresponding with these pawls are provided with selection feet arranged in a staggered manner at different heights to co-operate with the pawls.

4. A device as claimed in any of claims 1 to 3, in which a wire extends at right-angles over all the needle push-rods, the arrangement being such that by engagement of a said push-rod foot with said wire, a desired needle push-rod and the respective auxiliary push-rod can be put out of operation.

5. A single needle selection device for flat knitting machines, in which a carriage travels to and fro with a cam arrangement and needle selection heads above needle beds to actuate auxiliary push-rods associated with each needle and controled by electromagnets, which auxiliary push-rods each raise a corresponding needle push-rod when a corresponding needle is selected and push a foot of the needle push-rod into the path of movement of the cam arrangement said selection device being substantially as hereinbefore described with reference to the accompanying drawings.