BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic side view of the drafting system of a draw frame having one embodiment of apparatus according to the invention;
FIG. 2 shows a portion of FIG. 1 in section corresponding to K-K (FIG. 1) with a pneumatic upper roller weighting device;
FIG. 3 is a front view of a presser arm having an integral housing and two presser rods;
FIG. 3
a is a perspective view of the presser arm according to FIG. 3;
FIG. 4 is a section through one illustrative arrangement of an inductive displacement sensor in a pressure-medium system according to the invention;
FIG. 5 is a diagrammatic view of the inductive displacement sensor of FIG. 4 with a plunger coil and a plunger core;
FIG. 5
a is a plan view of the plunger coil of FIG. 5; and
FIG. 6 is a diagrammatic block circuit diagram of an electronic control and regulation device (evaluation device) having an inductive displacement sensor, memory element, 4-channel evaluation means and display device.
DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS
With reference to FIG. 1, a drafting system S of a draw frame, for example a draw frame TC 03 made by Trützschler GmbH & Co. K.G. of Mönchengladbach, Germany. The drafting system S is configured as a 4 over 3 drafting system, that is to say it consists of three lower rollers I, II, III (I output lower roller, II middle lower roller, III input lower roller) and four upper rollers 1, 2, 3, 4. In the drafting system S, the drafting of the fibre bundle 5, which consists of a plurality of slivers, is carried out. The drafting operation is composed of the preliminary drafting operation and the main drafting operation. The roller pairs 4/III and 3/II form the preliminary drafting zone and the roller pairs 3/II and 1, 2/I form the main drafting zone. The output lower roller I is driven by the main motor (not shown) and thus determines the delivery speed. The input and middle lower rollers III and II are driven by a regulating motor (not shown). The upper rollers 1 to 4 are pressed against the lower rollers I, II, III by presser elements 91 to 94 (weighting device) in presser arms 11a to 11d which are pivotable about pivot bearings (see FIG. 3) and are thus driven by way of frictional engagement. The direction of rotation of the rollers I, II, III; 1, 2, 3, 4 is indicated by curved arrows. The fibre bundle 5, which consists of a plurality of slivers, runs in direction A. The lower rollers I, II, III are mounted in stands 14 (see FIG. 2) which are arranged on the machinery frame 15. Reference numeral 29 denotes a compressed air supply, with reference numerals 28a, 28b, 28c and 28d indicating channels communicating between air supply 29 and presser elements 91 to 94.
In FIG. 2 there is shown in more detail the presser element 94, although presser elements 91 to 93 are of the same or essentially the same construction. According to FIG. 2, the pneumatic cylinder 9 is associated at the top with a support element 12 and at the bottom with a holding element 13a. The pneumatic cylinder 9 forms a cylinder unit with a cylinder cavity 17 having two portions 17a and 17b in which a piston 18 is guided by means of a presser rod 19a in a sliding bush 20. The roller journal 4a of the upper roller 4, passing through an opening in a holding bracket 24a, engages in a bearing 22a. The bearing 22a accommodating the upper roller 4 extends into a chamber between the presser rod 19 and the roller journal IIIa of the lower roller III. The bearing 22a is held by means of a shoulder 26 in the holding element 13a. A membrane 16 divides the cylinder cavity 17 in terms of pressure. In order that pressure is generated in the upper portion of the cylinder cavity 17, the latter can be supplied with compressed air p1 by means of a compressed air connection 23 to line 28a (see FIG. 1). The lower portion of the cylinder cavity 17 is vented by means of a venting bore 24. The upper portion of the cylinder cavity 17 can be vented and the lower portion of the cylinder cavity 17 can be supplied with compressed air in corresponding manner. In operation, after a fibre bundle 5 has been guided over the lower rollers I, II, III, the presser arms 11 are pivoted into the operating position shown in FIG. 3 and fixed in that position by a fastening device (not shown), so that the presser rollers I, II, III are able to exert pressure. Such a pressing action is produced on the one hand by the fact that the presser rods 19 each rest on the corresponding bearing 22 and on the other hand because an overpressure has been generated in the cavity above the membrane 16. As a result, the presser rod 19 presses with its other end on the bearing 22 in order to create the mentioned pressing action between the upper roller 4 and the lower roller (drive roller) III. The presser rod 19 (piston rod) is displaceable in the direction of arrows D, E.
In the embodiment shown in FIG. 3, 3a, the upper roller 4 is associated with a portal-shaped presser arm 11a. (The upper rollers 1 to 3 are associated with a corresponding presser arm 11—not shown). In this embodiment, the presser arm 11a is in the form of a housing 30 of glass-fibre-reinforced plastics and is produced by injection-moulding. The housing 30 is an integral component which is of unitary construction and comprises the support element 12, the two bodies of the presser elements 9a1 and 9a2 (pressure cylinders), two intermediate elements 31a and 31b and two holding elements 13a and 13b. The support element 12 is in the form of a channel 33 of approximately U-shaped cross-section that is open on one side, in the interior of which pneumatic lines 34 and electrical leads 35 are arranged. The open side of the channel 33 is closable by a removable cover 36, partly cut away in FIGS. 3 and 3a, which consists of glass-fibre-reinforced plastics, is approximately U-shaped in cross-section and is resilient so that it is attached to the channel 33 by a press-fit connection. The housing 30 is preferably formed in one piece. The integral housing 30, which combines all essential functional elements for holding and weighting the respective upper rollers 1 to 4, is in this way economical to produce. At the same time, the entire presser arm 11a to 11d is in simple manner pivotable about the pivot bearing 10 and can be locked and unlocked by a locking device (not shown). The presser rods 19a and 19b are relieved of load and thus raised from the bearings 22a and 22b of the upper roller 4 at distance b1, b2, respectively.
FIG. 4 shows one form of presser element 9 in which there is a compressed-air-operated pressure-medium cylinder consisting of a cylinder housing 6 in which a piston 18 is arranged so as to be axially movable. A piston rod 19 (presser rod) extends from the piston 18. The piston rod 19 emerges from a cover-side opening 7 of the pot-shaped cylinder housing 6. The opening 7 and the inner wall of the cylinder housing 6 serve for guiding the piston 18 with the piston rod 19. The piston rod 19 cooperates—in the manner described at the beginning—with an upper roller 4 of a drafting system for fibre material. The upper roller 4 consists of a metal cylinder 41, to which a roller covering 42 (hollow cylindrical in cross-section) made of an elastomer is attached. The pot-shaped cylinder housing 6 is closed with respect to the end face remote from the opening 7 by a cylinder base 8. In this exemplary embodiment, the connection between the cylinder housing 6 and the cylinder base 8 is in the form of a clip connection. The cylinder base 8 has a pressure-medium connection 25 for acting upon a pressure chamber 32 of the pressure-medium cylinder. Furthermore, in the region of the pressure chamber 32, a guide recess 33 is provided in the cylinder base 8. The guide recess 33 corresponds with a cylindrical extension 37 which is screwed into the piston rod 19 coaxially therewith to form a lengthwise extension thereof. The corresponding screw connection 37 serves simultaneously also for attaching the piston 18 to the piston rod 19. A compression spring 39 is arranged between the piston 18 and the cover 6a of the cylinder housing 6. Using the spring-returnable piston 18, in the non-pressurised state the piston 18 is always returned to the end position by mechanical means.
The cylinder base 8 is provided for accommodating an inductive displacement sensor 43 which consists of a plunger core 44 and a plunger coil 45. The inductive plunger core 44 consists of a metal covering, for example, a metal coating, thin-walled metal cap, hollow cylinder or the like, which is applied over the outer free end of the cylindrical extension 37. The plunger core 44 moves back and forth in the guide recess 33 in the direction of arrows D, E. The inductive plunger coil 45 is in the form of a hollow cylinder, the outer wall surface of which is in contact with the cylindrical inner wall surface of the guide recess 33. The cylindrical inner wall surface of the fixed plunger coil 45 is located opposite and spaced apart from the cylindrical outer wall surface of the plunger core 44. By being used in the pressure chamber, the inductive displacement sensor 43 is protected from dust.
Furthermore, formed on the cylinder housing 6 there is a radially inwardly directed annular shoulder 41 which acts as upper end stop for the piston 18. Reference numeral 42 denotes a peripheral, approximately ring-shaped elastomeric seal between the piston 18 and the inner wall of the cylinder housing 6.
Referring now to the schematic illustration in FIG. 5, an electrical lead 46 is connected to the plunger coil 45. The plunger core 44, which is in the form of a solid metal cylinder, is attached to the free end of the extension 37 (for example made of plastics), for example by means of a screw connection. As shown in FIG. 5a, the plunger coil 45 is substantially annular in cross-section.
In an exemplary control arrangement shown in FIG. 6, the inductive displacement sensor 43 (or via lead 46 the plunger coil 45) is connected to an electronic control and regulation device 47, for example a microcomputer having a microprocessor. Furthermore, the control and regulation device 47 is connected to a memory element 48 which is able to store the measured values of the inductive displacement sensor 43 and predetermined desired values, for example maximum and minimum values. In addition, a 4-channel evaluation device 49 and a display device 50 (lap and/or wear message) are connected to the control and regulation device 47.
Using the apparatus according to the invention, by means of the contact pressure of the piston rod 19 on the roller covering 42 of the upper roller 4 and accordingly the determination of the position of the piston 18, it is possible for both lap and wear to be displayed.
Although the foregoing invention has been described in detail by way of illustration and example for purposes of understanding, it will be obvious that changes and modifications may be practised within the scope of the appended claims.
Patent Application
20080087000
