GB2083507A

GB2083507A - A rapid invention electromagnet particularly for flat bed knitting machines

Info

Publication number: GB2083507A
Application number: GB8028279A
Authority: GB
Original assignee: O MA TEX RIMACH Srl
Current assignee: O MA TEX RIMACH Srl
Priority date: 1980-08-30
Filing date: 1980-08-30
Publication date: 1982-03-24
Also published as: GB2083507B

Abstract

A rapid intervention electromagnet is provided especially for flat bed knitting machines. The electromagnet has a cam (KA) operating keeper AN position such that a spool of the electromagnet is located between a keeper fulcrum CU and a stem of the cam controlled thereby. The core of the electromagnet comprising a stationary portion NF within the spool and a movable core portion NM movable with the keeper. <IMAGE>

Description

SPECIFICATION A rapid intervention electromagnet particularly for flat bed knitting machines This invention relates to a rapid intervention electromagnet particularly suitable for flat bed knitting machines.

The application of electronics for selecting the needles of knitting machines requires an electromagnet which is both sufficiently powerful and very rapid in its interventions.

Moreover a minimum overall size is required since it is necessary to align a plurality of the electromagnets in parallel with a very short separation between them.

The present invention seeks to provide an embodiment of an electromagnet which satisfies to the requirements whereby when installed in a Jacquard flat bed knitting machine a high output may be expected.

According to one aspect of the invention there is provided a rapid intervention electromagnet for the selection of members in machines characterized in that a cam actuating keeper operates as a third class lever for which purpose a spool of an electromagnet is located between a keeper fulcrum and a stem of the cam to be controlled, the core of the electromagnet comprising a stationary portion secured with said electromagnet spool and a movable core portion movable with the keeper.

One embodiment of the invention will now be described by way of example, reference being made to the accompanying drawings in which: Fig. 1 shows an elevational view of a rapid intervention electromagnet for the selection of the needles particularly for flat bed knitting machines, this figure showing the operative position; Fig. 2 shows a similar view to Figure 1 but with the electromagnet in its inoperative position; and, Fig. 3 shows a plan view of the electromagnet of Figures 1 and 2.

With reference to these figures PR shows an L-profiled angle piece, which is rigidly fixed (see screws SC) to a platform namely to the frame of a carriage CA. Carriage CA carries a number of electromagnets aligned with one another in a direction perpendicular to the plane of the Fig. 1.

The carriage CA is so mounted as to be reciprocable in the operative directions FA-FB (see Figure 3).

An upper end SE of the profiled iron PR is bifurcated (fork shaped), the tips of the fork branches each being machined as a spire whereby two pivot tips result for a keeper AN. In this manner (as is required), friction is reduced to a minimum value.

In order to take up any possible slack or play otherwise occasioning movement of the keeper AN perpendicularly to the plane of the Fig. 1 , the keeper AN presents a U-shaped terminal portion ES whereby it is positioned (located) by a locating stem (post) BP fixed by the screws VI- VI to the vertical branches AL of the profiled angle piece PR.

A stationary magnetic core NF is fastened (see screw SW) to the carriage CA. Core NF presents an electromagnetic winding AE wound around the insulation reel RO. The stationary core NF extends along 2/3 ony of the whole height of the spool for the reason to be explained hereinafter.

A return spring MR (represented only in broken lines) is hooked at one end to a hook GA, which is fixed to the keeper AN, and at its other end to a spike VP, which is fixed to the upright portion AL of the profiled angle piece PR.

A cam KA is provided to operate the components selecting the needles. This cam KA presents a prismatic shape with a triangular base and is fixed to the guide stem traversing the carriage body CA.

A return spring MO biases the cam KA in a direction FC (see arrow FC) away from the needle selecting members, for example away from the "platine" (not shown). This return spring MO is mounted, to be under compression, between a shoulder SP of the stem STand an insulation base BS.

As is known, the stroke necessary for the keeper AN to operate the needle selecting members is nearly 23 millimeters and the operating frequency for the cam KA may reach, 40 strokes/second.

In view of these circumstances, the keeper AN operates as a third class lever whereby very small displacements of the movable keeper AN correspond to consistent displacements of the camKA.' In order to increase the efficiency of the electromagnet and permit an intervention of 40 times/second, the keeperAN of the electromagnet is not flat but it extends with a projecting portion formed as movable core NM which axially penetrates along 1/3 of the whole height of the spool.

LA-AL shows two rubber rings absorbing the shocks deriving from the cam strokes.

It is remarked (see Figures 1 and 2) that the spool is located between the fulcrum CU of the keeper and the stem STof the cam KA whereby the stroke of the movable core NM is shorter than the stroke of the cam KA. This enables the high frequency of the movable core NM to be consistent with the requisite stroke of the cam KA.

The operation is evident.

1. A rapid intervention electromagnet for the selection of members in machines characterised in that a cam actuating keeper operates as a third class lever for which purpose a spool of an electromagnet is located between a keeper fulcrum and a stem of the cam to be controlled, the core of the electromagnet comprising a stationary portion secured with said electromagnet spool and a movable core portion movable with the keeper.

2. A rapid intervention electromagnet as claimed in Claim 1, characterized by a bifurcated member with spire profiled tips for pivotally

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION A rapid intervention electromagnet particularly for flat bed knitting machines This invention relates to a rapid intervention electromagnet particularly suitable for flat bed knitting machines. The application of electronics for selecting the needles of knitting machines requires an electromagnet which is both sufficiently powerful and very rapid in its interventions. Moreover a minimum overall size is required since it is necessary to align a plurality of the electromagnets in parallel with a very short separation between them. The present invention seeks to provide an embodiment of an electromagnet which satisfies to the requirements whereby when installed in a Jacquard flat bed knitting machine a high output may be expected. According to one aspect of the invention there is provided a rapid intervention electromagnet for the selection of members in machines characterized in that a cam actuating keeper operates as a third class lever for which purpose a spool of an electromagnet is located between a keeper fulcrum and a stem of the cam to be controlled, the core of the electromagnet comprising a stationary portion secured with said electromagnet spool and a movable core portion movable with the keeper. One embodiment of the invention will now be described by way of example, reference being made to the accompanying drawings in which: Fig. 1 shows an elevational view of a rapid intervention electromagnet for the selection of the needles particularly for flat bed knitting machines, this figure showing the operative position; Fig. 2 shows a similar view to Figure 1 but with the electromagnet in its inoperative position; and, Fig. 3 shows a plan view of the electromagnet of Figures 1 and 2. With reference to these figures PR shows an L-profiled angle piece, which is rigidly fixed (see screws SC) to a platform namely to the frame of a carriage CA. Carriage CA carries a number of electromagnets aligned with one another in a direction perpendicular to the plane of the Fig. 1. The carriage CA is so mounted as to be reciprocable in the operative directions FA-FB (see Figure 3). An upper end SE of the profiled iron PR is bifurcated (fork shaped), the tips of the fork branches each being machined as a spire whereby two pivot tips result for a keeper AN. In this manner (as is required), friction is reduced to a minimum value. In order to take up any possible slack or play otherwise occasioning movement of the keeper AN perpendicularly to the plane of the Fig. 1 , the keeper AN presents a U-shaped terminal portion ES whereby it is positioned (located) by a locating stem (post) BP fixed by the screws VI- VI to the vertical branches AL of the profiled angle piece PR. A stationary magnetic core NF is fastened (see screw SW) to the carriage CA. Core NF presents an electromagnetic winding AE wound around the insulation reel RO. The stationary core NF extends along 2/3 ony of the whole height of the spool for the reason to be explained hereinafter. A return spring MR (represented only in broken lines) is hooked at one end to a hook GA, which is fixed to the keeper AN, and at its other end to a spike VP, which is fixed to the upright portion AL of the profiled angle piece PR. A cam KA is provided to operate the components selecting the needles. This cam KA presents a prismatic shape with a triangular base and is fixed to the guide stem traversing the carriage body CA. A return spring MO biases the cam KA in a direction FC (see arrow FC) away from the needle selecting members, for example away from the "platine" (not shown). This return spring MO is mounted, to be under compression, between a shoulder SP of the stem STand an insulation base BS. As is known, the stroke necessary for the keeper AN to operate the needle selecting members is nearly 23 millimeters and the operating frequency for the cam KA may reach, 40 strokes/second. In view of these circumstances, the keeper AN operates as a third class lever whereby very small displacements of the movable keeper AN correspond to consistent displacements of the camKA.' In order to increase the efficiency of the electromagnet and permit an intervention of 40 times/second, the keeperAN of the electromagnet is not flat but it extends with a projecting portion formed as movable core NM which axially penetrates along 1/3 of the whole height of the spool. LA-AL shows two rubber rings absorbing the shocks deriving from the cam strokes. It is remarked (see Figures 1 and 2) that the spool is located between the fulcrum CU of the keeper and the stem STof the cam KA whereby the stroke of the movable core NM is shorter than the stroke of the cam KA. This enables the high frequency of the movable core NM to be consistent with the requisite stroke of the cam KA. The operation is evident. CLAIMS

2. A rapid intervention electromagnet as claimed in Claim 1, characterized by a bifurcated member with spire profiled tips for pivotally mounting the keeper, and by the keeper being fork shaped and embracing an upright post secured to a frame member on which the electromagnet is mounted whereby any deviating movement of the keeper is prevented.

3. A rapid intervention electromagnet as claimed in any preceding claim, wherein said selected members are knitting needles in flat bed knitting machines.

4. A rapid intervention electromagnet arranged, constructed and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.