US2681080A - Unwinding and releasing means for the warp beam of weaving looms - Google Patents

Description

June 15, 1954 J. PICANOL 2,681,080 UNWINDING AND RELEASING MEANS FOR THE WARP BEAM OF WEAVING LOOMS 5 Sheets-Sheet 1 Filed Sept. 2'7 1951 June 15, 1954 J. PICANOL UNWINDING AND RELEASING MEANS FOR THE WARP BEAM OF WEAVING LOOMS 5 Sheets-Sheet 2 Filed Sept. 27, 1951 Ja Zea/w M ran/m0 2,681,080 s FOR June 15, 1954 J. PICANOL UNWINDING AND RELEASING MEAN THE WARP BEAM OF WEAVING LOOMS 5 Sheets-Sheet 3 Filed Sept 27 1951 100k Pzcano IIVVE Jae/1w M June 15, 1954 J. PICANOL 2,631,080

UNWINDING AND RELEASING MEANS FOR THE WARP BEAM OF WEAVING LOOMS Filed Sept. 27, 1951 5 Sheets Sheet 5 Patented June 15, 1954 UNWINDING AND RELEASING MEANS FOR THE WARP BEAM OF WEAVING LOOMS Jaime Picanol, Zandberg, Zillebeke-lez-Ypres, Belgium Application September 2'7, 1951, Serial No. 248,603

7 Claims. (01. 139-110) The present invention relates to weaving looms mechanisms and, more particularly, means for releasing and positively unwinding the warp beam in proper synchronism with the opposite cloth beam.

Of course, the unwinding movement of the warp beam in weaving looms must be co-related, or synchronized, with the winding action of the finished fabric on the cloth beam, so that the warp tension will remain substantially constant irrespective of the various factors tending to vary this tension. One important such factor is created by the progressively decreasing diameter of the warp beam and the resulting variation in the rotational speed of the beam by the unwinding warp; this permanent change in the warp beam feed necessitates constantly a re-adjustment of the warp beam rotational speed if a constant tension on the warp threads is to be maintained.

Warp unwinding means are known in which the beam is geared to a secondary shaft which, through the intermediary of a second gear train, is connected to a ratchet wheel device, the ratchet pawl of which being actuated by a suitable element of the loom. In such an arrangement an accessory mechanism is provided for regulating the amplitude of the rotational movement transmitted to the warp beam.

The result is a Warp beam which is unwound in a jerky manner, exactly in accordance with the variations occurring in the pull exerted on the warp threads.

Furthermore, for varying the feeding action of said beam, various devices have been suggested in which a braking mechanism for the beam is sometimes used.

In such braked warp beams, for instance, it has been proposed to control the warp thread tension by a member normally stopped by a brake, which member is released when the thread tension exceeds a given predetermined maximum safe value, and returns to an active braking position as the thread tension returns below said safe value.

Also, in said braked devices, an escapement mechanism, combined with the brake, has been tried for varying the oscillation amplitude of the element controlled by the escapement in accordance with the warp thread tension. Y

The present invention has been conceived to avoid the drawbacks noted above in a warp beam speed-regulating mechanism embodying a braking action in a novel and improved manner.

Consequently, the main object of the invention may be stated to reside in the provision of improved means for the highly eflicient unwindin and releasing of warp beams.

Another important object contemplates a mechanism of the character noted which is simple of construction and in use.

A further object relates to warp beams controlling means which are rugged and, for all their improved character, relatively inexpensive.

Still another object envisages a mechanism of the character described in which the braking action is exerted on a driving member only during the return stroke of its movement.

Other objects and advantages of the invention will become apparent, or be pointed out further during the description to follow.

Substantially, the device of the invention is composed of at least one driving element having a reciprocating motion of constant amplitude, said driving-element being adapted to move a rocker having a ratchet pawl engageable with a ratchet wheel to rotate the warp beam in the unwinding direction. Said rocker is provided with a sector swingable opposite a brake shoe. The rocker is urged to a given start limit position by a spring, while the brake shoe is connected by a suitable linkage to the whip-roller, or back rest and is also actuated by the driving element at the end of the return course of the latter. The braking force exerted by the brake under the control of the whip-roller will retard more or less the rocker during its return course, but will be insufiicient to block the rocker during its forward movement, that is: in the unwinding direction of the warp beam because said forward movement is caused by the positive action of the driving element. The braking force exerted by the brake under the action of the driving element will stop the rocker at whatever position it has attained at the end of the return course of the reciprocating driving element.

Thus, if the tension of the warp yarns is normal, that is constant and of about the ideal predetermined tension, at each forward movement of the driving element the rocker is swung in the unwinding direction of the warp beam and drives same through a ratchet. On the return stroke of the driving element, said rocker tends to be brought back to its start limit position by the spring but is retarded and finally stop ed by the brake in a, predetermined intermediate position. This movement repeats itself and the warp beam is thus unwound step by step according to the winding of the cloth. If, for any reason, the tension of warp yarns decreases, an immediate loss of pressure will exist on the whip roller, which will cause an increase of the braking efi'ort by the brake shoe. As said shoe exerts more effort on the sect-or of the rocker, the latter is more r..- tarded and is prevented from returning entirely to said intermediate position. It is thus blocked on its way back from its end limit position at a location depending on the tension of the warp yarns.

The rocker being thus kept blocked between its intermediate position and its end limit position, the driving element will only engage the rocker after a certain distance has been run and which could be called dead distance. During this dead time the warp beam does not unwind and the cloth is still being taken-up by the other beam; consequently, tension on the warp yarns increases until it reaches a Value equal to, or approaching, the ideal predetermined tension.

Conversely, if the tension on the warp-threads increases, the tension on the whip roller will increase proportionally and the brake linkage will release the brake shoe from the sector of the rocker driving the warp beam. Said rocker will then be brought back by the return spring into its start limit position.

Consequently, as the driving element is displaced towards the rocker, it will meet the same sooner and will entrain it on a larger angular course, to which course corresponds a greater driving of the warp beam and, also, an increased feed of the threads. This increased feed will automatically cause a reduced tension on the said threads until a value equal to, or near, the ideal predetermined tension is reached.

Through these relatively simple means, a practically constant thread tension can be assured through the simple expedient of so retarding the return movement of the rocker that it can be blocked at the right moment during the return course of the driving element.

This conception is thus somewhat different from that practiced up to the present. It can be adapted under quite diversified forms, according to the nature and the relative position of the elements being used.

As an example, and for purposes of illustration only, an embodiment of the invention is shown in the annexed drawings, wherein:

Figure 1 shows schematically and in a simplified manner, the position of the warp beam unwinder in a weaving loom,

Figures 2, 3, 4 and show schematically the essential elements of the unwinding device in four characteristic positions.

Figure 6 is an enlarged elevation view of the unwinding mechanism shown at the lower left of Figure l, and

Figure 7 is a section taken on line VIIVII of the Figure 6.

In weaving looms the warp beam is generally supported by a shaft I journalled on both sides in the side posts 2. This warp beam is driven by a ratchet wheel 3 mounted on a shaft 4 having a bevel pinion 5 meshing with a second pinion 6 on the shaft 7 of which a worm gear 8 is mounted, said worm driving a helicoidal gear 9. The shaft I 9 of this gear 9 carries a toothed wheel I! driving a toothed crown 12 mounted on the shaft l of the warp beam.

The unwinding means, object of the invention and associated with said ratchet wheel 3 (shown schematically in Figures 2 to 5), is composed principally of the following elements: a rocker l3 mounted freely on the shaft 4 of ratchet wheel 3 carries an extension sector [4. .The

rocker l3 has at least one ratchet pawl I5 engaging the ratchet wheel 3, said rocker being urged permanently to an initial position by a return spring 53 secured to a fixed point I! of the loom frame. The rocker l3 has a stud I8 engaged in the fork it formed at the end of the rod 20, which rod is pivoted to the end of a constant-amplitude oscillating arm 2| mounted on shaft 22. The rod 26 thus constitutes a constant-amplitude reciprocating member.

Opposite the sector I4 is disposed a brake shoe 23 which is mounted on a crank 2t pivoted at one end at 25 and at the other end at the foot of a rod 26. About at the foot of said rod, the connecting rod 24 rests on a spring 21 which is held by the adjusting nut 28.

The rod 26 is upwardly pivoted to a pin 29 projecting from the 'arm 30 of a crank 3! adapted to rotate about the pivot 32. The lower extremity of the crank 3| is connected to a return spring 33 secured at one end to a tension screw 3% threadedly engaged at a point 35 in the frame of the loom. The upper end of the crank 3| is linked by a small connecting rod 35 to a bell crank lever 31 journalled on a fixed pin 38, the upper arm of the crank supporting the whip roll 35.

Assuming (Figure 2) the tension of the warp yarns as being normal, that is: equal or quite near the ideal predetermined tension, the rocker 13 will be retarded and finally blocked by the brake 23 in an intermediate position such that the angle a which it sweeps, is equivalent to a normal unwinding of the warp beam in order to keep constant this predetermined tension. Under these conditions, the rod 28, positively driven by the lever 2| will tend to move said rocker l3 forwardly so as to sweep said angle a.

As long as this predetermined tension subsists, the brake will always operate in the same way and the rocker 13 will always be brought by the spring l6 to the same intermediate position corresponding to the amplitude a.

If the tension of the warp threads increases, it will exert a stronger pressure on the whip roller 39 whereby the latter will be displaced downwardly, the bell crank lever 31 will rotate in anticlockwise direction and will cause clockwise rotation of the crank 3! and consequently downward movement of the rod 26 and clockwise rotation of the crank 24 with its brake 23; this will cause the release of the rocker l3 which will be brought through the action of the spring H3 in the start limit position a1 a (Figures 2, 3 and 4). From then on, the moving rod 20, will encounter the stud l8 sooner and will displace the rocker [3 by the angle a1, thus moving the warp beam to let off a greater length of warp threads.

In other words, the dead run length of the driving rod 20 decreases as the tension of the warp threads increases, whereby the eifective run of said driving rod 20 increases the unwinding of the warp beam.

If, on the contrary, the tension of the thread decreases (Figure 5) the corresponding pressure of the warp threads on the whip roller 39 decreases also, whereby the braking action of the brake 23 will increase so as to prevent the rocker l3 from returning to its intermediate position.

In other words, the rocker I3 will be blocked by the brake after having swept an angle a2 u. As the rod '20 continues its return movement, the fork [9 moves further away from the stud l8, thus increasing the length of the drivind rod dead run. From this results also that the rod 20 will displace the rocker 13 by the amplitude a only, thus causing a reduced unwinding of the' beam, until such time as the tension of the warp yarns becomes normal again when the retarding action of the brake on the rocker l3 will be decreased so that the rocker l3 will again reach its intermediate position and will have a motion of amplitude a.

Thus, the warp threads pressure variations on the roll as act on the brake 23 to block at the right moment the rocker IS in its return movement; in such conditions that the active course of said lever is, in some way, inversely proportional to the tension of the warp yarns. Indeed, the greater this tension becomes, the smaller the active course of the rocker l3 will be and the smaller will also be the unwinding of the warp beam, and vice versa.

Figures 6 and '7 show in more detail such a device. In this embodiment, there is a rocker 13 having two ratchet pawls 15, each one meshing with the ratchet wheel 3. This ratchet wheel is integral with a brake drum 4t freely mounted on the shaft l. A brake band 4| surrounds the brake drum 46. One end of said brake band 4| is held at 42, on the frame of the loom, the other end being secured to the slider 53 which may be operated by a handle 44, so as to actuate the brake at will, in order to prevent the apparatus being placed in action by the vibrations and the effort exerted by the warp. The driving rod 20 passes through an aperture made in the crank 3| and has, beyond said crank 31, a portion 45 of a greater diameter and ended facing said crank 3| in the shape of a semi-spherical cap 46. Near the end of the return movement of rod 20, this cap 46 will butt against the corresponding part of crank 34, and will rotate the same in anticlockwise direction such as to cause upward displacement of rod 26 and consequently the brake 23 will completely block the rocker I3 in whatever position the latter has reached at the moment the cap 46 acts on the crank 3 I.

It must of course be possible to operate the warp beam manually, for the initial adjustment of the tension on warp threads and more particularly when putting a new warp beam in place. To this effect, the shaft 4 driving the first pinion 5 is extended outwardly and equipped with an operating hand wheel 41 keyed thereto and with an interlocking handle 48 secured to an arm 49 pivoted around a pin 55 pressing through the hub of the hand wheel 4?. This arm 43 is provided with at least one lug 5| interlocking normally with a toothed crown 52 of the brake drum 493 and this interlocking is helped by a spring 53 placed between said arm as and the above mentioned hand wheel 41. Therefore, if the hand wheel 41 is rotated manually when the lug 5| engages the crown 52, the shaft 4 as well as the ratchet wheel 3 will be actuated simultaneously. On the contrary, if the handle 48 is pushed inwardly so as to disengage the lug 5| from the crown 52, and is then rotated, only the shaft 4 will be rotated and the ratchet wheel 3 will remain inactive.

As it is necessary to allow for the adjustment of the initial tension of the warp yarns according to the kind of cloth, or for any other reasons, an adjusting hand wheel has been foreseen, which regulates the tension of the spring 33, this spring balancing the effort produced by the tension of the warp yarns on the back rest 39.

All of the described elements could, of course, be replaced by equivalent elements or elements with equivalent function.

It must be understood that various changes as" to the shape, size and arrangement of parts maybe resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

What I claim is:

1. Warp beam unwinder for weaving looms having a whip roll, comprising means for unwinding the warp beam of a loom, and a constant-amplitude reciprocating member capable of actuating said unwinding means, spring call-back means for said unwinding means, a brake adapted to retard and arrest the unwinding means during its return movement, and means dependent upon the warp tension on the whip roll for controlling the brake action, whereby the oscillating member encounters the unwinding means during its active course at various places thereof according to the tension of the warp threads on the whip roll.

2. In a weaving loom having a warp beam and a whip roll, a rocker oscillatable around a pivot, at least one ratchet pawl mounted on said rocker, a ratchet wheel adapted to unwind the warp beam, a constant-amplitude reciprocating member for driving the rocker in the unwinding direction of the beam, spring means for returning said rocker to a start position, a brake adapted to retard and arrest the rocker during its return movement and brake actuating means controlled by the warp tension on the whip roll, whereby said brake will arrest the rocker at positions dependent upon the warp tension and the reciprocating member will encounter the rocker at the positions of rocker arrest.

3. In a weaving loom having a warp beam and a whip roll, unwinding means for said Warp beam comprising a rocker having a driving stud, at least one ratchet pawl on said rocker, a ratchet wheel engageable by the pawl and adapted to unwind said beam, a driving rod having a fork at one end for engaging the rocker stud, means for imparting to said driving rod a constant-amplitude reciprocating movement for rocking the rocker in the unwinding direction, spring means for returning the rocker to a start position, a brake adapted to retard and arrest the rocker during its return position, and brake energizing means controlled by the warp tension on the whip roll and by said driving rod for retarding and arresting said rocker at positions corresponding to the warp tension, whereby the rod will contact the rocker stud at the arrested positions of the rocker in accordance with the warp tension.

4. In an unwinding mechanism for the warp beam of a weaving loom having a whip roll, a rocker having at least one ratchet pawl and a drive stud, a ratchet wheel engageable by the pawl and adapted to cause unwinding of the warp beam, 2. constant-amplitude oscillating arm, a driving rod pivoted at one end to said arm, a fork at the other end of the rod engaging the rocker stud for moving said rocker in the unwinding direction of the warp beam, spring means for returning the rocker to a start position, a sector mounted on said rocker, and a brake shoe engageable with said sector and controlled by the warp tension, whereby the reciprocating drive rod encounters the rocker stud at various positions thereof corresponding to the warp tension.

5. In a mechanism as claimed in claim 4, a pivoted crank supporting the brake shoe, and a linkage between said crank and the warp whip roll.

6. In a mechanism as claimed in claim 5, the

linkage comprising a crank supporting rod, an arm pivoted to said rod, an intermediately pivoted crank integral with said arm, spring means at one end of said last named crank, a connecting rod at the other end of said last named crank, and a bell-crank lever connected at one end to the connecting rod and at the other to the Whip roll.

'7. In a mechanism as claimed in claim 6, the driving rod reciprocating adjacent the last named crank and formed with a semi-spherical cap adapted to engage the spring end of said last 8 named crank at the end of the return movement of said driving rod to move said last named crank in a direction to cause arresting of said rocker.

References Cited in the file of this patent UNITED STATES PATENTS

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