GB2238798A - Strand braiding apparatus - Google Patents

Abstract

In a strand braiding apparatus (10) comprising relatively movable pluralities of outer spools (An) and inner spools (In) circulating in opposite directions and feeding inner strands and outer strands, respectively, to a braiding point (19) for formation of a braided casing around a hose (12), cable or the like, to provide uniform braiding with crossing over of inner and outer strands in correct sequence, the outer strands are moved at non-uniform speed along a sinuous epicycloid path by means of respective strand-guiding devices (20) comprising a hollow guide axle (25) journalling a guide arm (24) and arranged eccentrically on an annular bearing (23) carried on a mounting stud (22) on the rotating carrier (14) of the outer spools (An). Rotatably mounted on the bearing is a planetary bevel gear rim (Z8) which carries a crank drive pin (26) drivingly coupled with the guide arm, eg by a roller (27) in a slot, and translating constant speed rotation of the bevel gear rim into changing rotational speed of the guide arm. <IMAGE>

Description

-1 STRAND BRAIDING APPARATUS 2 2::3 a -7E:-:) a The present invention

relates to strand-guiding apparatus, in particular braiding apparatus for the forming of braided strands, for example ropes, or for formation of braided casings around strand-like stock, for example hoses or cable.

Braiding machines are known, which operate on the so-called "maypole principle". In these machines, the supply spools with their supply of strands (wire or textile) to be braided, their carrier elements and driving elements as well as a strand tension force regulator are guided past each other on curvilinear guide paths around the machine axis, so that the strands drawn off the spools and fed to a central braiding point undergo regular crossing-over and form a braid, for example "under 2 over 2".

This "maypole principle" has the disadvantages that large masses are moved on curvilinear paths and during the course of the guidance these assume different spacings from the machine axis. In addition, the spools inclusive of the mentioned functional elements are mounted in cantilever fashion and exhibit corresponding top-heaviness. This results in, inter alia, increasing centrifugal forcesand periodically different spacings of the strand-guiding elements from the central braiding point during the spool circulation.

Consequently, strong oscillations are imposed on the machine and the functional elements are highly stressed. Moreover, the constant changes in spacing give rise to appreciable differences in tension force between the individual strands, notwithstanding strand length storage arrangements (cf.prospectusses of Mayer-Rothkopf/USA and Babcock/GB).

A circular braiding machine is also known from DE-PS 2 743 893. This machine operates with supply spools moving around along circular paths, wherein the inner and outer spools circulate in opposite direction. Crossing-over of strands is effected by strand-guiding devices which are disposed in the proximity of the outer supply spools and which on the basis of pivotable guide arms are driven by means of coupling gears circulating with the outer supply spools. As a result, the outer strands,are moved into and out of the circular track of the inner supply spools.

This machine has the disadvantages that a large number of axles, joints and deflecting rollers are needed for rectilinear guidance of the guide arm tip and greater tension stress differences are introduced into the strands through the superimposed pivotation and longitudinal displacement of the entire strand-guiding arms. Morever, the strandguiding arms must periodically change pivotal direction, whereby. appreciable mass forces, component stresses and machine oscillations occur with the large number of the deflecting elements per guide arm (coupler, intermediate lever, joints and strand-guiding arm with deflecting rollers).

A braiding machine is also known, which operates on the "outer wheel principle" (see prospectus of VEB Schnellflechter Berlin). This machine is equipped with two rows of circularly rotating supply spools. The inner row of spools is guided on a annular path around the machine axis and driven by means of bevel gear wheels, while the outer row of spools rotates at the same speed in opposite direction to the inner row of spools. The strands from the outer row of spools are guided in such j 1 t a manner by bevel gears, which are associated with each outer spool and which are guided about the machine axis against the inner row of spools and roll along a fixed gear rim, that the strands describe a cycloidal path due to the rolling of the gears along the gear rim and to eyelets mounted at the rims of the gears.

This machine has the disadvantage that uniform braiding "under 2 over V' cannot be achieved, but only non-uniform braids "under 1 over V'. The reason is that in the uncorrected simple epicycloid, the dwell time in the lower setting of the strand-guiding eyelet in the cycloid loop is lo sufficient to permit crossing-over of only one inner spool, whilst the strand-guiding eyelet allows two inner spools to be crossed over in the upper arcuate course of the epicycloid. The non-uniform braid entails losses of strength for the stock that has been encased in the braiding, which is of particular consequence in the case of pressure hoses. Thus, this machine cannot be used for high-pressure hoses, but only for products of low strength requirements.

There is thus a need for apparatus which by simple means may improve the serviceability properties of manufactured braided products through increase in mechanical strength and which may also have increased working productivity and improved health protection for operating personnel as a consequence of reduced noise levels. Preferably, the apparatus should permit uniform braid formation, for example, "under 2 over V', through a system of rotational driving and strand-guiding movements in which components for the guiding of the strands from outer supply spools do not have to execute reversing movements, may be subjected to lower loading and wear and may develop less noise.

According to the present invention there is provided strand guiding apparatus, in particular braiding apparatus for the formation of strandshaped braids, comprising inner and outer supply spools relatively movable in opposite direction for braid-forming crossing-over of inner and outer strands by means of constrainedly guided elements driven by toothed wheels, a carrier disc provided at its outer circumference with a plurality of mounting members, an annular bearing mounted on each mounting member and receiving a rotatable planetary bevel gear rim, a hollow guide axle journalling a guide arm and mounted on the mounting member eccentrically of the centre of the bearing and within the circumference of the bearing, and a crank pin arranged on the planetary bevel gear rim in the proximity of its outer circumference and drivingly coupled to the guide arm, which at its free end has a strandguiding element which, together with the arm form a strand-guiding lever, wherein the guidance of each outer strand to be braided takes place from the outer supply spool arranged on the mounting member by way of one or more deflecting rollers through the hollow guide axle and by way of one or more deflecting elements through the strand-guiding element to a central braiding point.

In a preferred embodiment, the outer spools are disposed in circular arrangement on the carrier disc, which is rotatable in a first direction about a stationary hollow axle. The inner spools are also disposed in circular arrangement and are acted on by a driving toothed rim arranged on the carrier disc for the purpose of execution of a rotary movement of the inner spools relative to the outer spools along a stationary spool path ring on the hollow axle, wherein the strands of the outer spools are led into and out of the region formed by the circular part of 1 t the inner spools in order to achieve braiding of the inner and outer strands- with each other or around a core. Arranged within the circumference of the bearing on each mounting member is the hollow guide axle for reception of a guide arm, the axle being disposed eccentrically of the axis of the wheel bearing. The planetary bevel gear rim, which is rotatably mounted on the bearing, is provided in the region of its outside diameter with a crank pin which stands in connection with the guide arm. Disposed at the free eno of the arm guide is the strandguiding element. The guidance of stock to be braided takes place from the outer spool on the mounting member by way of several deflecting rollers through the hollow guide axle by way of deflecting elements through the strand-guiding element to the braiding point.

The connection between crank pin and guide arm can be provided by a roller which is arranged at the free end of the pin and runs in a track, for example engages in a slot, along the guide arm. Alternatively, the connection between pin and guide arm is provided by a slide ring which slides in the track or engages in the slot.

Through the use of rotational driving and strand-guiding movements with the omission of reversing movements, working productivity may be increased through greater rotational working speeds, noise levels and wear may be lowered, and the mechanical strength of braided products, such as bursting pressure and dynamic pulse strength, may be increased through the attainment of a uniform braid formation "under 2 over P'.

This uniform braid binding "under 2 over 21' is achieved because the planetary bevel gear rim and crank pin rotate at uniform angular speed, while the guide arm or strand-guiding level rotate, by virtue of the eccentricity, at non-uniform angular speed. In an inwardly directed - 6 setting of the lever, i.e. at the greatest spacing of the crank pin from the axle, the strand-guiding element at the free end of the lever has the lowest angular speed and describes the path of a sinuous epicycloid while passing below the strand of an inner spool, while its dwell time is increased on entry into slots between the inner spools, whereby at least one strand more of the inner spools can move over the entered intercalated) outer strand.

An embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, 10 in which:

Fig. 1 is a schematic elevation of braiding apparatus embodying Fig. 3 the invention; Fig. 2 is a diagrammatic illustration of the paths of movement an outer strand relative to inner strand supply spools in the apparatus, so as to achieve crossing-over of the inner and outer strands; is a schematic illustration of the relative arrangement of the inner and outer strand supply spools; and Fig. 4 is a fragmentary view of the braid binding "under 2 over P' in a product manufactured by means of the apparatus.

Referring now to the drawings, there is shown in Fig. 1 a braiding machine 10 comprising a hollow axle 11 through which a hose 12 or similar is drawn by means of drawing equipment during formation of a braided casing therearound. The axle 11 is fixedly mounted in a housing 13 and carries a rotatable carrier disc 14 as well as a stationary spool path ring 15.

The carrier disc 14 is driven by way of an intermediate gear from a 2 :i 1 toothed wheel paid z4 and z5. The outer supply spools An(A 1 A 12) are firmly mounted on the carrier disc 14 and rotate with this in clockwise sense.

Disposed adjacent to the rotatable carrier disc 14 is the stationary spool path ring 15, which guides the inner supply spoolsIn (I1 112) on their circular path around the hollow axle 11. The inner spools are driven from the bevel gear Z1 fastened to carrier disc 14, by way of inner wheel pins 16 mounted in the spool path ring 15 with bevel gears Z2 and by way of toothed segments Z3, which are in turn fixedly connected with inner carriages 17 and spool carriers 18.

The inner spools In circulate at the same rotational speed as the outer spools An, but in opposite direction, thus in counter-clockwise sense.

The inner strands to be traided from the inner spools are conducted substantially directly from the spools by way of guide rollers at the spool carriers 18 to a braiding point 19 and include an angle with the axis of the axle 11.

The outer strands from the outer spools must, during the movement relative to the inner spools, be led periodically into and out of the region enclosed by the circular path of the inner spools. For realisation of this braid-forming crossing-over of the strands, the inner spools must be passable at all sides and able to be crossed unhindered at least in sections by the outer strands. Corresponding strand-guiding devices 20 are provided for the inwardly and outwardly extending control movement.

The passability of the inner spools is achieved in that a constant spacing is maintained between the individual inner spools In inclusive i of the respective spool carriers 18 and toothed segments Z3 with carriages 17, that the spool path ring 15 has slots 21 at uniform spacings in the intermediate gaps between the inner wheel pins 16 for the entry of the outer strands and that the toothed wheels Z2 continuously pass between themselves the toothed segments Z3 with spool carriers 18 and inner spools In in the circular path, while at least one toothed wheel Z2 is always in engagement with the respective toothed segment Z3.

Each strand-guiding device 20 consists of a respective stud 22 arranged at the outer circumference of the carrier disc 14 and provided with a wheel bearing 23 receiving a rotatable planetary bevel gear rim Z8 and with a hollow guide axle 25 which is disposed within the circumference of the bearing 23 and which journals a guide arm 24. In that case, the spacing of the centre line of the bearing 23 from the centre 1 i ne of the hol 1 ow axl e 25 i s denoted as eccentri ci ty e.

The planetary bevel gear rim Z8 in the proximity of its ou'te, circumference carries a crank drive pin 26, at the free end of which is arranged a roller 27 which is disposed in anelongate slot of the guide arm 24. The arm 24 at its free end has a strand-guiding element 28 and together with this forms a strand-guiding lever 29.

On circulation of the carrier disc 14, driven by the toothed wheel Z4, with the outer spools An and the studs 22, the planetary bevel gear rims Z8 roll along a stationary sun bevel gear wheel 27 and in that case move the levers 29 by way of the respective pin 26 and roller 27 from an outwardly directed setting to an inwardly directed setting and conversely from the inwardly to the outwardly directed setting.

The planetary bevel gear rim Z8 and the crank pin 26 in that case 1 circulate at a uniform angular speed, whilst the guide arm 24 and thus strandguiding lever 29 move at a non-uniform angular speed by reason of the eccentricity e. In the outwardly directed setting of the lever 29., the crank drive 5 pin 26 has its smallest spacing a from the axle 25 and the lever 29 consequently has its greatest angular speed, whilst in the inwardly directed setting of the lever 29, the greatest spacing a' of the crank pin 26 from the axle 25 is present and the lever analogously has its smallest angular speed. 10 The tip of the lever 29 with the strandguiding element 28 in that case describes the path of a sinuous epicycloid as shown by Fig. 2. The guide-travel/time behaviour of the strand guidance of the outer strands in co-operation with the circulating movement of the inner spools and their inner strands becomes clear from this. The steps of the outer spools or by analogy the oppositely running steps of the inner spools are illustrated from 0 to 30 in the horizontal scale, wherein 24 partial steps denote a crossing-over period "under 2 over P'. The steps 01 to 25' of the strand-guiding element 28 are entered on the sinuous epicycloid, wherein these steps are associated in time with the steps of the supply spools, i.e. step 2' of the element 28 is, for example, executed at the same point in time as step 2 of the outer spool Al and steps 18 to 16 of the inner spool Il. Consequently, the strand from spool A1 is positioned at 6' by its element 28 after 6 partial steps, whilst spool 11 moved from step position 18 to 12 and thus crossed over the strand from spool Al.

After 12 further steps, the strand from spool Al after execution of the loop 61 to 181 assumes the position 181 and spool 12 moves to the step position 12, whereby the strand from spool Al is crossed over for the second time.

On the 6 following steps, the strand from spool A1 reaches position 24' and the strand from spool 13 reaches step position 18, whereby the strand from spool A1 is crossed over for the first time.

The second crossing-under is experienced by the strand from spool A1 after 6 further steps when it has reached the position 30' (corresponding to the position 6' analogously one crossing-over period later) and spool 14 then assumes the step position 24.

The continuous course of all inner spools In and outer spools An in the described manner effects a progressive and uniform crossing-over of the strands in "under 2 over V' braiding and enables the manufacture of a uniform braided casing.

Fig. 3 schematically shows the relative arrangement and rotational direction of the inner and outer spools as seen from the braiding point 19. The result of the uniform braiding of the inner and outer strands "under 2 over V' is illustrated as a detail in Fig. 4.

1 1

Claims (7)

1. Strand braiding apparatus comprising a plurality of outer spools for feeding outer strands to a braiding point, a plurality of inner spools for feeding inner strands to the braiding point, drive means to effect relative movement of the two pluralities of spools in mutually opposite directions, and a plurality of strand guide devices respectively associated with the outer spools agd operable to guide the outer strands to the braiding point along paths periodically intercalating with paths of the inner strands to the braiding point, each device comprising a mounting member, a hollow axle mounted on the mounting member, an arm rotatably mounted at one end thereof on the axle and provided at the other end thereof with a strand guide element for receiving the outer strand from the associated outer spool by way of the bore of the axle and guiding the strand to the braiding point, and an annular planetary gear which is drivable by the drive means and mounted on the mounting member by way of an annular bearing to extend around the axle and to be rotatable about an axis offset from the axle and which is provided with a crank drive element drivingly coupled to the arm to translate rotation of the gear at constant speed into rotation of the arm at changing speed.

2. Apparatus as claimed in claim 1, wherein the mounting members of the guide devices are aranged at the outer circumference of a carrier disc.

3.

Apparatus as claimed in either claim 1 or claim 2, the drive means comprising toothed wheels.

4. Apparatus as claimed in any one of the preceding claims, wherein each of the devices comprises deflecting means for deflecting the outer strand of the respective outer spool to pass from the spool to the axle bore and from the axle bore to-the strand guide element.

5. Apparatus as claimed in any one of the preceding claims, wherein each crank drive element comprises a pin provided at a free end thereof with a roller running in a track along the associated arm.

6. Apparatus as claimed in any one of claims 1 to 4, wherein each crank drive element comprises a pin provided at a free end thereof with a slide element slidably engaged in a track along the associated arm.

7. Apparatus substantially as hereinbefore described with reference to the accompanying drawings Published 1991 at The Patent 0Mce. State House. 66171 High Holborn. London UTCIR 47P, Further copies May be obtained from Sales Branch. Unit 6. Nine Mile Point Cwmfelinfach. Cross Keys. Nmrport. NPI 7HZ. Printed by Multiplex techniques lid. St Mary Cray. Kent.