GB1571521A - Apparatus for crimping synthetic yarns and the like - Google Patents

Description

(54) APPARATUS FOR CRIMPING SYNTHETIC YARNS AND THE LIKE (71) We, VEPA AKTIENGESELL SCHAFT of 32 Bettingerstrasse, 4125 Riehen-Basel, Switzerland; Swiss body corporate do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:: The present invention relates to an apparatus for crimping synthetic yarns and the like comprising a pair of pressure rollers and a stuffer box placed subsequent to the rollers when viewed in the direction of material passage. the stuffer box comprising two plates which are axially aligned with the rollers, of which at least a portion is tiltable towards the other to reduce the volume of the stuffer box, and two side walls fixed to the non pivotable plate, which side walls laterally define the chamber to the nip of the pressure rollers, a thrust disc associated with the edge region of the end face of the rollers being provided on said walls, which disc is engaged by an automatically operating control member which maintains the thrust disc at a predetermined minimum spacing, without frictional abutment, from the end faces of the roller.

In order to permit the crimping operation to be effected continuously, without interruption. over a long period of time. it is essential to ensure that the gap between the rollers at their end faces is accurately sealed.

Thrust discs which abut with pre-tension against the end faces of the pressure rollers have been utilised for thins purpose.

Although this ensures substantially perfect sealing. the thrust discs are however. subjected to increased wear due to constant friction between the discs and the end faces of the rollers.

In order to avoid the necessity of replacing worn thrust discs at regular intervals, the thrust discs have been rotatably and. preferably, eccentrically mounted relative to the gap between the rollers so as to avoid the formation of a tongue~ in the region of the gap caused by the friction. This ensures uniform abrasion over the entire surface of the thrust disc, so that it may be readily used for a long period of time without replacement.

However, even an arrangement of this type can only operate satisfactorily if the thrust disc has been extremely accurately adjusted.

In theory, this is perfectly feasible.

However, in practice the relevant parts of the device expand and contract due to the effects of temperature changes, which cannot be avoided. When operating a device of this type, the pressure rollers must firstly be heated to their operational temperature.

However, during the operation thereof, they must be cooled to ensure that the temperature of the rollers remains substantially constant. A thermostat will keep the temperature constant to a certain extent, but can only control the temperature within a range. Changes in the dimensions of the rollers are therefore unavoidable. Accordingly, the dimensions of the rollers are thus constantly changing in dependence upon the prevailing temperature, even if such changes are only of the order of hundredths of millimetres.

To take into account the maximum amount of thermal expansion, which obviously takes place when the rollers are initially heated to their operational temperature, the location of the thrust discs is adjusted when the operational temperature is reached. However, the crimping operation, and hot steam which may be injected into the chamber to fix the crimp cause further thermal expansion, which causes the thrust discs to rub against the pressure rollers.

It has been suggested to utilise a sensor member which maintains the thrust disc in a predetermined spaced relationship from the end faces of the rollers without frictional abutment against the end faces of the roller, to overcome this problem. Such a sensor member may be a feeler which is fixed to be adjacent the end faces of the roller, either with or without contact. Such a refinement must have a very sensitive reaction and is therefore a delicate construction which cannot withstand the robust treatment it receives during the operation of a crimping machcine. Hence, the apparatus is excessively prone to breakdown. The present invention seeks to provide a thrust disc setting device which can withstand the rigours of permanent operation of the crimping device and which does not require continual adjustment.

According to the present invention, there is provided an apparatus for crimping synthetic yarns and the like comprising a pair of pressure rollers and a stuffer box placed subsequent to the rollers when viewed in the direction of material travel, the stuffer box comprising two plates axially aligned with the rollers, one plate being pivotable towards the other to reduce the volume of the stuffer box. and two side walls defining the lateral edges of the stuffer box extending to the nip of the pressure rollers and being fixedly retained bv the non-pivotal plate, a thrust disc, associated with each end face of the roller pair. being provided in the side walls, an automatically operating adjustment member engaging against the thrust disc and at least one control member connected to the disc which retains the thrust disc at a minimum predetermined spacing, without frictional abutment. from the end faces of the roller pair, wherein the control member is formed as a device which discontinuously urges the thrust disc. at predetermined time intervals against the end face of the roller pair and immediately afterwards disengaging the disc from the roller pair by the minimum predetermined spacing.

Accordingly. the control device forming part of the apparatus of the present invention is not a sensor device in its generally accepted sense. but is a device which forc ibly urges the thrust discs against the end surfaces of the rollers at predetermined time intervals. This sets the spacing between the discs and the rollers and then retracts the thrust discs by the minimum predetermined spacing from the end surfaces of the roller which permits non-frictional operation. In this manner. by a more durable construc tion. a substantially uniform, optimum spac ing between the thrust discs and the end faces of the rollers can be maintained.

Accordingly, no specific wear phenomena appear on either the thrust disc or on the end faces of the rollers.

Particular problems arise when the crimping machine is shut down for example, overnight, and is allowed to cool. The spacings of the thrust discs from the rollers change in such circumsances so that the thrust discs abut with considerable force against the end faces of the rollers. This is because the crimping chamber, in operation, is heated to a temperature of 100" to 1300C. Reheating of the pressure rollers results in expansion of the plates and hence causes the thrust discs to move away from the end faces of the roller. When the chamber cools, the thrust discs, in dependence upon the extent of contraction of the plates move closer to the rollers which contract to a lesser extent. Without readjustment, therefore, a high degree of wear of the thrust discs is to be expected.

To solve this problem a thermostat preferably forms part of the apparatus of the present invention. This thermostat, inde pendently, of the pulsed adjustment, activates the apparatus for adjusting the spacing of the thrust discs. In this way, the machine also operates satisfactorily if, due to negligence, the machine is not adjusted by the operator when the machine is reused after a lengthy cooling-off period.

The invention will be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a transverse section through part of a known stuffer box crimping device, for comparison purposes; Figure 2 is a longitudinal section through a further known stuffer box crimping device, also for comparison purposes; Figure 3 is a view similar to that shown in Figure 2 of a further known stuffer box crimping device.

Figure 4 is a transverse section through the device shown in Figure 3, and Figure 5 is a schematic sectional view of a device exemplifying the present invention.

In Figure 1, there is shown a part of a known stuffer box crimping device. This figure, apart from certain changes in reference numerals, is identical to Figure 8 of our prior British Patent Specification No.

1364911. The stuffer box crimping device comprises a pair of feed rollers 1 and 2. The device also comprises side walls 3 and 4 into which are sunk, level with the nip of the rollers 1 and 2, thrust discs 5. The thrust discs 5 are freely rotatable in a keyway 6 and each disc 5 is pressed against the face of the respective rollers by means of a piston and cylinder unit 7.

The thrust discs 5 are subjected to a constant pressure which is sufficient to cause them to rest on the faces of the rollers 1 and 2 with as little danger of wear as possible. If, however, a certain degree of pressure is exerted on the discs 5 from the direction of the nip of the rollers 1 and 2, the discs 5 can be held in position by the pressure of liquid passing through a non-return valve 8, one such valve being associated with each unit 7.

The existing pressure from the nip of the rollers 1 and 2 may greatly exceed the pressure exerted by the piston and cylinder unit 7 onto the respective thrust disc 5 without causing any lifting of the thrust discs 5 from the roller faces.

The surface of each thrust disc 5 which faces the feed rollers 1 and 2 constantly rubs on the outer sections of the rollers. This could cause the thrust discs 5 to be unevenly worn. To eliminate this the thrust discs 5 are caused to rotate continuously about an axis whilst the crimping device is operating. This axis is located at a small distance from the roller nip. It therefore follows that, since the axis of the thrust disc 5 is eccentrically shifted relative to the nip, a rotating force is exerted by the rollers which causes the thrust disc to be uniformly worn across its entire surface.

In Figure 2, there is shown a further known stuffer box crimping device which figure, apart from certain changes in reference numerals, is identical to Figure 1 of our prior British Patent Specification No.

1365650. In this Figure, the top and bottom plates, 9 and 10 respectively, of the device are shown. The top plate 9 can be adjusted relative to the bottom plate 10 to reduce the size of the stuffer box.

A bracket 11 is also shown in this Figure to which sleeves are fixed. The sleeves carry bearings for the rollers 1 and 2.

The stuffer box crimping device shown in Figures 3 and 4, is a further modified version of the device shown in Figures 1 and 2, Figures 3 and 4 corresponding, with the exception of reference numerals to Figures 1 and 2 of our German Patent Application No. 2403970. The top plate 9 is still adjustable relative to the bottom plate 10. The side walls 3 and 4 of the stuffer box are mounted on the bottom plate 10. Thrust discs 5 are again provided to seal the stuffer box chamber in the region of the nip of the rollers 1 and 2. However, in this case, the discs 5 do not frictionally engage the end faces of the rollers 1 and 2. These discs 5 therefore act purely as sealing discs.The clearance between the discs 5 and the end faces of the rollers may be as small as hundredths, or even thousandths, of a millimeter and this spacing may be maintained irrespective of any temperature fluctuations causing elongation or contraction of the rollers. It will be appreciated that such temperature fluctuations take place due to the use of the superheated steam to cause the rollers to assume their operational temperature. and the passage of water for cooling through the rollers whilst crimping is taking place.

For accurately maintaining the spacing between the thrust or sealing discs 5 and the end faces of the rollers, a feeler member 12 is provided. In the embodiment shown, the feeler member 12 penetrates the side plates 3 and 4 and its free end abuts the end faces of the rollers 1 and 2. The other end of the feeler member 12 is connected to an adjust ment unit such as a piston and cylinder unit 7. The piston of the unit 7, at its free end, carries the disc 5. The working of the piston and cylinder unit to accurately maintain the spacing of the discs 5 from the end faces of the cylinder is controlled by an electrical control circuit (not shown). However, as mentioned hereinbefore, such an arrange ment is a relatively delicate construction and ,is prone to breakdowns.

As aforementioned, the present invention seeks to solve this problem by discon tinuously urging the thrust disc, at predeter mined time intervals against the end faces of the rollers and, immediately thereafter, disengaging the disc from the rollers. This can be effected in a variety of ways, one of which is shown in Figure 5. The control member for discontinuously urging the thrust disc 5 against the end faces of the roller, as shown, comprises an electric motor 13 which cuts out when a predeter mined torque is reached. The torque is obviously dependent, to some extent, on the abutment of the thrust disc 5 against the end face of the rollers. The adjustment member may, in such a case, be a speed monitor 14, worm gears 15, 16 and a timing device 17.

The speed monitor 14 is utilised for deter mining the cutting-out of the motor by causing the motor to cut out when a predetermined speed is reached, which speed corresponds to the predetermined torque. The motor 13 acts on the discs 5 through the intermediary of the worm gears 15, 16. The motor 13 is then reversed in direction and run for a predertermined time so that the discs 5 are moved a small amount away from the end faces of the rollers. To achieve this, the timing device 17, which is pre-set, is provided in conjunction with the motor 13. The motor 13 may be mounted, as an additional member, on the bracket shown in Figure 3.

It can therefore be seen that, effectively, an arrangement in accordance with the present invention provides a combination of the most desirable features of the inventions disclosed in our prior British Patent Specifi cation Nos. 1364911 and 1365650, and our German Patent Specification No. 2403970.

In an arrangement in accordance with the present invention the thrust disc is not permanently in engagement with the end faces of the roller (as is the case in our above-identified British Patent Specifica tions) nor is the maintenance of a minimal spacing between the discs and the ends of the rollers dependent upon the use of an easily-damaged feeler (as is the case in the above-identified German Patent Specification).

WHAT WE CLAIM IS: 1. An apparatus for crimping synethetic yarns and the like comprising a pair of pressure rollers and a stuffer box placed subsequent to the rollers when viewed in the direction of material travel, the stuffer box comprising two plates axially aligned with the rollers, one plate being pivotable towards the other to reduce the volume of the stuffer box, and two side walls defining the lateral edges of the stuffer box extending to the nip of the pressure rollers and being fixedly retained by the non-pivotal plate, a thrust disc, associated with each end face of the roller pair being provided in the side walls, an automatically operating adjustment member engaging against the thrust disc and at least one control member connected to the disc which retains the thrust disc at a minimum predetermined spacing, without frictional abutment, from the end face of the roller pair, wherein the control member is formed as a device which discontinuously urges the thrust disc, at predetermined time intervals, against the end face of the roller pair and immediately afterwards disengaging the disc from the roller pair by the minimum predetermined spacing 2. An apparatus as claimed in claim 1, additionally comprising a thermostat. which thermostat actuates the control member is dependance upon temperature fluctuations.

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

Claims (2)

**WARNING** start of CLMS field may overlap end of DESC **. spacing between the discs and the ends of the rollers dependent upon the use of an easily-damaged feeler (as is the case in the above-identified German Patent Specification). WHAT WE CLAIM IS:

1. An apparatus for crimping synethetic yarns and the like comprising a pair of pressure rollers and a stuffer box placed subsequent to the rollers when viewed in the direction of material travel, the stuffer box comprising two plates axially aligned with the rollers, one plate being pivotable towards the other to reduce the volume of the stuffer box, and two side walls defining the lateral edges of the stuffer box extending to the nip of the pressure rollers and being fixedly retained by the non-pivotal plate, a thrust disc, associated with each end face of the roller pair being provided in the side walls, an automatically operating adjustment member engaging against the thrust disc and at least one control member connected to the disc which retains the thrust disc at a minimum predetermined spacing, without frictional abutment, from the end face of the roller pair, wherein the control member is formed as a device which discontinuously urges the thrust disc, at predetermined time intervals, against the end face of the roller pair and immediately afterwards disengaging the disc from the roller pair by the minimum predetermined spacing

2. An apparatus as claimed in claim 1, additionally comprising a thermostat. which thermostat actuates the control member is dependance upon temperature fluctuations.