US2699051A

US2699051A - Warp tension control device for knitting machines

Info

Publication number: US2699051A
Application number: US224000A
Authority: US
Inventors: Harold C Noe
Original assignee: Kidde Manufacturing Co Inc
Current assignee: Kidde Manufacturing Co Inc
Priority date: 1951-05-01
Filing date: 1951-05-01
Publication date: 1955-01-11
Anticipated expiration: 1972-01-11

Description

H. c. NOE

Jan. 11, 1955 WARP TENSION CONTROL DEVICE FOR KNITTING MACHINES 2 Sheets-Sheet 1 Filed May 1, 1951 INVENTOR. BY Karma! /V56 ATTORNEY Jan. 11, 1955 H. c. NOE 2,699,051

WARP TENSION CONTROL DEVICE FOR KNITTING MACHINES Filed May 1. 1951 2 Shee ts-Sheet 2 II I n mm mllumlnlll lllllllllllllllllllllll mu gn v INVENTOR. filin CI 11 08 mzd.

ATTORNEY United States Patent WARP TENSION CONTROL DEVICE FOR KNITTING MACHINES Harold C. Noe, Upper Montclair, N. J., assignor to Kidde Manufacturing Co., Inc., Bloomfield, N. 1., a corporation of Delaware Application May 1, 1951, Serial No. 224,000

13 Claims. (Cl. 66-86) The present invention relates to warp knitting machines, and, more particularly, to improvements for supplying warp threads to the knitting elements of such machines.

Warp knitting machines of the type with which the present invention is concerned include a rotatably mounted warp beam for supplying the warp threads, knitting elements operated to knit the warp threads into fabric, a fabric take-up roll, and devices for controlling the supply and the tensioning of the warp threads. Preferably, the threads are let off the beam at a rate in a predetermined relation to the rate at which the fabric is taken up, and the threads preferably are led to the knitting elements under a substantially uniform predetermined tension.

The present invention aims to accomplish the foregoing in connection with warp knitting machines of the high speed type adapted to knit 400 or more courses per minute.

Accordingly, an object of the present invention is to provide a warp knitting machine wherein fluctuations in the tension of the yarn caused by the operation of the knitting elements are minimized.

Another object is to enable the warp threads to be let off continuously and supplied to the knitting elements under a desired uniform tension regardless of the decrease in diameter of the warp beam.

Another object is to utilize the tension of the threads to control the rate at which the threads are let off from the warp beam.

Another object is to arrange a pair of tension bars which cooperate with each other to minimize fluctuations in tension of the warp threads.

Another object is to provide improved tension bar structure which facilitates the foregoing.

Another object is to increase the speed at which high speed warp) knitting machines can be operated by the provision of the foregoing improvements.

A further object is to provide such improvements which are relatively simple, practical and economical in construction and are reliable in operation to assure continuous delivery of the warp threads at a predetermined rate and under a desired tension.

A still further object is to provide such improvements wherein the tension under which the warp threads are supplied is readily adjusted.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

In accordance with the present invention, the foregoing objects are generally accomplished by providing improvements comprising a variable speed drive mechanism in operative connection with continuous drive means and the warp beam of the warp knitting machine for effecting continuous rotation of the beam to let off warp threads, means such as a pivotally mounted tension bar over which the warp threads are adapted to pass for compensating variations in the tension of the warp threads and for controlling the drive mechanism to vary the speed at which the same effects rotation of the warp beam, and means such as a second tension bar between the knitting elements of the machine and the first mentioned tension bar for partially compensating fluctuations in the tension of the warp threads.

Either or both of the tension bars may comprise a rail 2,699,051 Patented Jan. 11, 1955 over which the warp threads are adapted to pass, a support, and a plurality of longitudinally spaced spring members each secured at one end to the support and carrying the rail at the free end thereof. Preferably, these members are generally C-shaped torsion springs.

A preferred embodiment of the invention has been chosen for purposes of illustration and description, and

is shown in the accompanying drawing, forming a part of the specification, wherein:

Figure 1 is a schematic end elevational view of a warp knitting machine illustrating the essential elements of the present invention.

Figure 2 is a fragmentary schematic front elevational view of the machine.

Figure 3 is a fragmentary sectional view taken substantially along the line 33 on Figure 2.

Referring to the drawings in detail, there is shown a portion of a warp knitting machine embodying the present invention with the conventional details of such a machine being omitted for the purpose of schematic illustration. This machine as shown generally comprises a pair of upright spaced apart

end frames

10 and 11, a warp beam 12 rotatably mounted on the end frames, a drive shaft 14 such as the cam shaft supported by the end frames, a variable speed drive mechanism 15 mounted on the end frame 11 adapted to be driven from the shaft 14 and in turn effect rotation of the warp beam, a pair of tension or flutter bars 16 and 17 over which the warp threads pass in being supplied from the beam to the knitting elements 19 herein schematically indicated, and means 20 for controlling the drive mechanism 15 in operative connection with the tension bar 17.

The tension bar 16, which is positioned between the tension bar 17 and the knitting elements, comprises a support such as a rod or bar 21, a rail 22 over which the warp threads pass, and a plurality of longitudinally spaced apart spring members 24 for mounting the rail 22 on the support. The ends of the support are mounted in bearings 25 formed in the

side frames

10 and 11, and are adjustably secured in a desired position therein by a set screw or the like (not shown).

The tension bar 17, which is positioned between the warp beam and the tension bar 16, comprises a support such as a rod or shaft 26, a rail 27 over which the warp threads pass, and a plurality of longitudinally spaced apart spring members 28 for mounting the rail 27 on the supporting rod 26. The ends of the rod 26 are pivotally mounted in bearings or trunnions 30 provided on the

side frames

10 and 11, and one end of the rod is operatively connected with the variable speed drive mechanism 15 by the control means 20 as will be described in detail hereinafter.

A shaft 31, rotatably mounted between the side frames, is positioned between the warp beam and the tension bar 17 for guiding the warp threads from the beam to this bar. I

As illustrated herein the

spring members

24 and 28 are in the form of flat, substantially C-shaped torsion the type for example, known in the trade as The Graham Variable Speed Transmission manufactured by Graham Transmissions, Inc., Milwaukee, Wisconsin, and illustrated in Bulletin No. 514 distributed by the manufacturer. Since the construction of such mechanisms is well known to those skilled in the art, detailed illustration and description thereof is believed to be unnecessary. Generally, such mechanisms comprise an input or driven shaft 36, an output or driving shaft 37, internal transmission elements (not shown) which are adjustable during operation of the mechanism for effecting a change of speed relation between the shafts, and a con- .trol arm 39 for adjusting these internal elements.

As illustrated herein, the shaft 36 is rotated by a sprocket 40 connected by a chain 41 to a sprocket 42 on the shaft 14, and the warp beam is rotated to let off the threads by a sprocket 44 connected by a chain 45 to the sprocket 46 on the shaft 37. The control arm 39 is operated by means 20 which comprise a rod 47 connected to an arm 48 secured on the shaft .26 whereby rotative movement of this shaft, in response to variations in tension of the threads passing over the tension bar 17, effects a change in speed of the output shaft 37.

In order to maintain the warp threads let ofi from the beam under a predetermined tension, the tension bar 17 is urged in a clockwise direction (as viewed) by a counterbalancing arrangement which comprises a lever arm 50 secured to the rod 26, and weight 51 supported on this arm. Preferably, the arm 59 is in the form of a frame having a rod 52 for slidably mounting the weight thereon to provide for varying the movement exerted about the shaft or rod 26, and having a threaded shaft 54 extending through a threaded bore of the weight and provided with a hand wheel 55 for rotating the same to adjust the position of the weight. While such a counterbalancing arrangement is shown only at one end of the rod 26, it will be understood that a similar arrangement may be provided at the other end of the rod (not shown) to more uniformly apply the counterbalancing force.

In operation of the machine, the shaft 14 is rotated continuously to effect continuous operation of the drive mechanism 15 which in turn effects continuous rotation of the warp beam to let off the warp thread. The Warp threads are guided under the shaft 31, over the

rails

27 and 22, and are received by the knitting elements 19 (Figure 3), the weight 51 being adjusted on the arm 50 to apply a desired tension to the threads.

As the knitting elements operate, the threads are alternately pulled and relaxed to cause fluctuations in tension of the threads which are partially compensated by the tension bar 16 which yields when the threads are pulled due to yarn demand by the knitting elements and returns when the threads are relaxed due to the resilience of the spring members. In practice, it has been found that the tension bar compensates about 75% of the fluctuations in the tension of the threads in the zone between the knitting elements and the rail 22.

The tension bar 17 similarly yields and returns to compensate the remaining fluctuations in tension of the threads in the zone between the

rails

22 and 27 so that the fluctuation in tension of the threads between the rail 27 and the warp beam is practically negligible.

However, as the warp beam decreases in diameter and is rotated at its initial speed to let off the threads, it cannot supply the constant thread demand of the knitting elements. Consequently, a decrease in the let off rate causes an increase in the tension of the threads between the beam and the tension bar 17. Since the rod 26 on which this tension bar is mounted is pivotally supported, such an increase in tension causes the rod to be turned in a counterclockwise direction to effect operation of the control element of the drive mechanism 15 whereby the warp beam is driven at an increased rate to let off the threads at a rate to meet the demand of the knitting elements and thus enable the counterbalancing elements to cause the tension bar 17 to maintain the yarn under the desired predetermined tension. The deflection of the

rails

22 and 27 takes place so rapidly that alternate pulling and relaxing of the threads do not effect material changes in the tension thereof. Likewise, the let off rate is rapidly adjusted to maintain the same substantially constant and in fixed relation to the demand of the knitting elements throughout the operation of the machine. The foregoing is accomplished while continuously rotating the warp beam whereby this arrangement of elements enables the knitting machine to function smoothly and efiiciently to produce fabric of high quality at a high production rate. From the foregoing description, it will be seen that the present invention provides novel and useful improvements in knitting machines which are simple and economical in construction and reliable in operation. The elements constituting these improvements are extremely rugged and can withstand long and continuous usage without wear or breakdown, thereby eliminating frequent shut down of the machine for replacement of parts or repair.

As various changes may be made in the form, construction and arrangement of the parts herein, without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in any limiting sense.

I claim:

1. In a warp knitting machine of the class described, the combination of drive means, a warp beam, a support, a rail over which the warp threads are adapted to pass, resilient means for mounting said rail on said support. a pivotally mounted bar between said support and said beam, a second rail over which the warp threads are adapted to pass, resilient means for mounting said second rail on said bar, a variable speed drive mechanism having a driven element in operative connection with said drive means and having a driving element in operative connection with said beam to effect rotation thereof, and means operatively connected with said pivotally mounted bar for controlling said drive mechanism.

2. A Warp knitting machine according to claim 1, wherein said support is fixed against movement.

3. A warp knitting machine according to claim 1, wherein both of said resilient means are in the form of a plurality of C-shaped torsion springs.

4. In a warp knitting machine of the class described, the combination of drive means, a warp beam, a pivotally mounted bar, a rail over which the warp threads are adapted to pass, a plurality of C-shaped torsion springs for mounting said rail on said bar, a variable speed drive mechanism having a driven element in operative connection with said drive means and having a driving element in operative connection with said beam to effect rotation thereof, and means operatively connected with said bar for controlling said drive mechanism.

5. A warp knitting machine according to claim 4, wherein counterbalancing means are connected to said bar.

6. In a warp knitting machine of the class described, the combination of a Warp beam, a variable speed drive mechanism in operative connection with said beam for eflecting rotation of said beam to let off warp threads, a pivotally mounted bar, a rail over which the warp threads are adapted to pass, a plurality of C-shaped torsion springs for mounting said rail on said bar, and means operatively connected with said bar for controlling said drive mechanism.

7. A warp knitting machine according to claim 6, wherein counterbalancing means are connected to said bar.

8. In a warp knitting machine of the class described, a warp tension bar comprising a rail over which the warp threads are adapted to pass, a support, and a plurality of longitudinally spaced C-shaped spring members each secured at one end to said support and carrying said rail at the free end thereof.

9. A warp tension bar according to claim 8, wherein said rail is U-shaped in cross section and said members have U-shaped portions at the free end thereof for mounting and securing said rail thereon.

10. A warp tension bar according to claim 8, wherein said support is a fixed bar.

11. A warp tension bar according to claim 8, wherein said support is a pivotally mounted bar.

12. A warp tension bar according to claim 8, wherein said support is a rotatably mounted bar and means are provided for securing said bar in fixed position.

13. In a warp knitting machine of the class described, the combination of a warp beam, a variable speed drive mechanism in operative connection with said beam for etfecting rotation of said beam to let off warp threads, a pivotally mounted bar, a laterally extending arm secured to said bar having a longitudinal groove, a weight having a threaded aperture and having a tongue in said groove adapted for slidable movement along said arm, a threaded rod extending through said aperture in said weight for adjusting the position of said weight on said arm, a manual control for rotation of said threaded rod, a rail over which the warp threads are adapted to pass, resilient means for mounting said rail on said bar, and means operatively connected with said bar for controlling said drive mechanism.

References Cited in the file of this patent UNITED STATES PATENTS 6 Plunkett et a1 Aug. 28, 1945 Lambach Aug. 31, 1948 Young May 17, 1949 Fuhrer Nov. 1, 1949 Clentimack Jan. 23, 1951