US3461718A - Thread tensioning apparatus - Google Patents

Description

Aug. 19, 1-969 I v, HARVEY ET AL 3,461,718

THREAD TENSIONING APPARATUS Filed Jan. 5. 1967 5 Sheets-Sheet 1 J. v. HA'fRVEY ET AL THREAD TENSIONING APPARATUS Aug. 19, 1969 3 Sheets-Sheet 2 Filed Jan. 5. 1967 Filed Jan. 5. 1967 THREAD TENSIONING APPARATUS 3 Shee ts-Sheet S V-SP x5:

3&4 -5

50 .50 o 1 i I 1 50 50 f ce 44646 United States Patent 3,461,718 THREAD TENSIONING APPARATUS John Vipond Harvey and John Rowson Thompson, Kingston, Ontario, Canada, assignors, by mesne assignments,

to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed Jan. 5, 1967, Ser. No. 607,419 Int. Cl. G011: 3/28; G011 /04 US. Cl. 73-955 6 Claims ABSTRACT OF THE DISCLOSURE The yarn-handling apparatus has clamps and a tensioning device which are activated in sequence to stop, clamp and tension a length of thread advancing to an aspirator. At the conclusion of a timed period for physical testing, the various elements are deactivated in reverse sequence. After another timed period, there is an automatic repetition of the same sequences.

. a tensioning device adapted to tension the clamped length of thread and a means for activating and deactivating the clamps and tensioning device in timed sequence.

Various details of the apparatus and its operation Will be apparent from the following specification wherein reference is made to the accompanying drawings in which:

FIGURE 1 is a front elevation showing one form of the apparatus;

FIG. 2 is a perspective View from the rear of the apparatus showing a drive roll mechanism for metering thread back from the aspirator;

FIG. 3 is a sectional view taken on line III-III of FIG. 1, showing the tensioning mechanism; and

FIG. 4 is a schematic diagram of pneumatic controls for various parts which engage the thread.

Referring to FIG. 1, the thread-engaging parts are shown mounted on a front panel 1. Thread comes from a package or other source (not shown), passes through a pigtail guide 2 and is withdrawn under low tension by an aspirator 3. A first clamp has a movable top piece 4 with three pins 5, a stationary bottom piece 6 with four pins 5, three neoprene pads 7 between the four pins of the bottom piece 6 and a single-acting piston-cylinder assembly 8. A second clamp has a stainless steel roll 9 supported on a bracket 10, a neoprene faced roll 11 reciprocably mounted by a yoke 12 and a single-acting piston-cylinder assembly 13. Intermediate the clamps,

there is a tensioning device which includes two pulleys.

14, 15 and between them is located another pulley 16 which moves downwardly in a slot 17 in front panel 1 to tension the thread. The testing equipment includes noncontacting thread vibrator 18 and a vibration detector 19. The thread line is drawn past two positioning guides 20, 21. In a use embodiment, vibrator 18 is a two-inch transistor radio speaker positioned closely adjacent the thread line and detector 19 includes both an ultra miniature lamp (Chicago CMB-666) and a photo transistor (Phillips OCP71). As explained more fully in connection with FIG. 4, the overall apparatus is controlled from a push-button 22 and a toggle switch 23.

A roll clamp drive mechanism for metering thread back from aspirator 3 is shown in FIG. 2. The steel roll 9 is keyed to a shaft 25 which is connected to a pinion 24. The pinion 24 is driven by a rack 26 and the rack is moved by a single-acting piston-cylinder assembly 27.

As shown in FIG. 3, the tensioning device has movable pulley 16 rotatably mounted on a shaft 28 which, in turn, is pivotally mounted on a hanger 29. Adjacent pulley 16, there is a tensioning weight 30 which can be varied for dilferent thread deniers. A counterweight 31 comprising two round knurled nuts serves to balance the tensioning arm with the tensioning weight 30 removed. The spring in a single-acting piston-cylinder assembly 32 normally holds a plate 33 and a lifting collar 34 in the raised position. Lifting collar 34 is attached to shaft 28. When in the raised position, pulley 16 is clear of the thread line. When plate 33 is lowered, pulley 1'6 rests on and tensions the thread.

With reference to FIG. 4, compressed air from a supply source 35 flows through valve 22 (or 23) and a double check valve 39 to one of the pilot actuators of a fourway double acting spool valve 42. This opens the valve and allows air to flow through a flow control-and-check valve 50 (e.g., a Clippard MFC-2) into the double acting piston-cylinder assembly 38 of a sequence control timer. Assembly 38 has a plunger 51 which moves out and trips five poppet valves 43-47 in sequence. As these valves are tripped, they allow air to flow through two-way flow control valves 52 to the decelerator clamp cylinder 8, the roll clamp cylinder 13, the tensioning arm cylinder 32 and the metering back cylinder 27. The fifth poppet valve 47 allows air to flow to the pilot actuator on a spool valve 41 which opens and passes air from source 35 through a flow control-and-check valve 50 to the double-acting piston-cylinder assembly 37 of a measurement timer. In its retraction, plunger 53 of assembly 37 opens a poppet valve 48 which in turn activates the other pilot actuator of spool valve 42. This causes plunger 51 to retract into assembly 38, sequentially releasing the air from cylinders 27, 32, 13, 8 and allowing their plungers to retract by spring action, under the control of valves 52. The pilot actuator on a spool valve 40 is also activated, allowing air to flow into the double-acting piston-cylinder assembly 36 of a stripping timer. The cycle is completed when plunger 54 of assembly 36 completes its stroke and opens the poppet valve 49.

To operate the apparatus of the present invention, thread is taken from a package, fed into the aspirator 3 and then drawn from left to right across the face of the apparatus and through the pigtail 2. The thread is stripped ofi the package and runs along the thread line A shown in FIG. 1. Automatic testing commences when the cycling Valve 23 is placed on the on position, permitting air to flow from source 35 through poppet valve 49 and check valve 39. The plunger 51 of assembly 38 moves out at a controlled rate and opens the first poppet valve 43. This activates the decelerator clamp pneumatic cylinder 8 which moves the top clamp 4 downwards at a controlled rate. Speed decreases as the thread passes in a zigzag line between the pins 5 and the thread is finally brought to rest and gripped between the pins of the top clamp 4 and the neoprene pads 7. The opening of the first poppet valve 43 also activates the spool valve 40 for stripping timer assembly 36 and the plunger 54 is extended in preparation for the next cycle. Plunger 51 opens the second poppet valve 44 which activates the roll clamp pneumatic cylinder 13. This brings the neoprene faced roll 11 down to grip the thread against steel roll 9. The tensioning arm cylinder 32 is activated whenthe third poppet valve 45 is opened, and the plate 33 is moved downwards. The tensioning arm mechanism moves down with plate 33 until pulley 16 engages with and rests on the thread between pulleys 14 and 15. At the instant pulley 16 contacts the thread, plunger 51 of the sequence timer assembly 38 opens the fourth poppet valve 46 and the metering back cylinder 27 is activated. The rack 26 then moves downwards, rotating pinion 24 and steel roll 9. A short length of thread is metered back between the steel roll 9 and the neoprene faced roll 11. This metered length allows pulley 16 to drop below and between pulleys 14, to a position of rest where the thread is tensioned by weight 30. This configuration of the thread line has been designated B in FIG. 1. Since the lengths of thread line B between pulleys 14, 15 are nearly vertical, any small change that takes place in the length between the two clamps will have little effect on thread tension. Thus, for practical purposes, a known length of thread is tensioned by a known amount. The thread tension can be varied for different deniers and types of thread by varying the magnitude of the tensioning weight 30.

The fifth poppet valve 47 is opened by plunger 51 and activates the spool valve 41 for measurement timer assembly 37. This determines the time interval during which a physical test is carried out on the thread. In the illustrated apparatus, the physical test is facilitated by stopping a known length of tensioned thread in close proximity to vibrator 18 and detector 19. Thread vibrations cause the incident light to fluctuate and induce a fluctuating voltage in the cell circuit. Usable outputs are obtained by coupling detector 19 to an electronic counter 55 (e.g., a Hewlett-Packard 5223L digital counter) and an automatic recorder 56 (e.g., a Hewlett-Packard 562A digital recorder).

After the period of time for the physical test has elapsed, retracting plunger 53 opens the poppet valve 48. This reverses the spool valve 42 for sequence timer assembly 38 and plunger 51 commences its return or deactivation stroke. The compressed air is first cut off at poppet valve 47. The return spring actuates spool valve 41 and plunger 53 moves out of measurement timer cylinder 37. Next, the metering back cylinder 27 is deactivated, and the return spring moves rack 26 upwards. Pinion 24 and the steel roll 11 rotate and the short length of thread metered back in the previous operation is withdrawn by aspirator 3. As plunger 51 retracts, poppet valve 45 closes and a return spring in the tensioning arm cylinder 32 raises the plate 33 which raises the tensioning arm mechanism. Shaft 28 pivots about its mount on hanger 29 and raises the pulley 16 clear of the thread line. Air is then released from the roll clamp cylinder 13 and the return spring raises neoprene roll 11 from steel roll 9, releasing the thread. Plunger 51 then closes poppet valve 43 which releases the air and allows the return spring in decelerator clamp cylinder 8 to raise top clamp 4 and release the thread. As the thread is no longer gripped by either clamp, aspirator 3 starts stripping the thread 011 the package (not shown) through pigtail 2 and across the face of the machine on thread line A.

When plunger 51 of sequence timer cylinder 38 opens poppet valve 43 on the retraction stroke, it also deactivates the spool valve 40 for stripping timer cylinder 36. The plunger 54 retracts at a controlled rate until it opens poppet valve 49. The interval of time the stripping timer assembly 36 allows the thread to be stripped off the package can be adjusted so a preset length of thread is stripped between tests. Since valve 23 is open, the opening of poppet valve 49 by return of plunger 54 reverses spool valve 42 and starts another cycle. In this mode of operation, the apparatus therefore functions automatically to perform a series of tests at preset time intervals.

Similarly, to obtain single tests, the thread is strung up and allowed to strip off the package. The push button valve 22 is then depressed, permitting air to flow from source 35 through check valve 39, and the apparatus runs through one activation-deactivation cycle. The thread will then recommence stripping off the package until the push button valve 22 is again depressed, the toggle valve 23 opened or the stripping stopped manually.

Although pneumatic elements have been described and illustrated, it is apparent that electronic, hydraulic and other systems of control would function equally as well and could be used without departing from the spirit of our invention which accordingly is intended to be limited only by the scope of the appended claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. An apparatus for imparting tension to a thread for testpurposes, said apparatus comprising: an aspirator to which the thread normally advances under low tension; a first clamp adapted to sequentially decelerate, stop and clamp the thread; a second clamp spaced from the first clamp and adapted to grip the stopped thread; a constant tension device located between the clamps, said device including a pair of axially fixed pulleys adapted for engagement by the clamped length of thread and a shaft carrying a third pulley and a counterweight, said shaft being pivotally mounted for swinging movement to and from a position where the third pulley rests on said clamped length between said pair of pulleys; instrumentation located adjacent the thread for testing a physical property of said clamped length; and means for activating and deactivating the clamps and said tension device in timed sequence, said activating-deactivating means including an extensible mechanism coupled to said shaft for its swinging movement from said position, said clamps and said tension device being located adjacent the normal path of advance to the aspirator.

2. The apparatus of claim 1 wherein the second clamp is located between the first clamp and said aspirator.

3. The apparatus of claim 2 wherein said second clamp comprises an axially fixed roll on one side of the thread and a reciprocably mounted roll on the opposite side of the thread, said activating-deactivating means including an extensible mechanism coupled to the latter roll for reciprocating it to and from a position of clamping engagement with the axially fixed roll.

4. The apparatus of claim 3 wherein is provided a drive mechanism coupled to said axially fixed roll for metering a short length of thread back toward said pulleys, thereby permitting the weighted pulley to swing beyond the axially fixed pulleys.

5. The apparatus of claim 1 wherein said activating-deactivating means includes a sequence control timer coupled to said clamps and the tensioning device for their activation and deactivation in timed sequence and a measurement timer also coupled to the sequence control timer for allowing a predetermined time interval for physical testing between activation and deactivation.

6. The apparatus of claim 5 wherein said activating-deactivating means includes a stripping timer coupled to the sequence control timer for its automatic reactivation after a predetermined length of thread has advanced away from the source.

References Cited UNITED STATES PATENTS 2,744,408 5/ 1956 Seney. 2,875,609 3/1959 Seney. 3,273,380 9/1966 Seney. 1,913,120 6/1933 Kenyon 73160 XR 1,941,917 1/1934 Schultz 7395.5 2,068,036 1/1937 Orling 73-460 X FOREIGN PATENTS 754,919 8/1956 Great Britain.

RICHARD C. QUEISSER, Primary Examiner I. W. MYRACLE, Assistant Examiner US. Cl. X.R. 73-160

Images