US3390705A - Dobby - Google Patents

Description

July 1968 A. OBERHOLZER DOBBY Filed Jan. 27, 1966 United States Patent ABSTRACT OF THE DISCLOSURE A dobby for effecting a programed movement of heald shafts on a loom, comprising a program carrier, means for sensing the program carrier and for actuating a plurality of auxiliary hooks in a programed manner to pivot at least one pivotable two-armed lever which is operatively associated with a draw hook. Depending upon actuation or non-actuation by an auxiliary hook, each pivotable lever determines an engaged or non-engaged position of the associated draw hook relative to a draw knife. Each draw hook has a projecting portion extending therefrom and each lever has its pivoting axis arranged so that in one of its pivoted positions the lever engages the projecting portion of the associated draw hook to position the hook in its non-engaged position and in the other pivoted position the lever moves away from the projecting portion, thereby determining the engaged position of the draw book. In this dobby construction, one of the ends of the lever travels in engagement along its associated draw hook during movement of the draw hook and the projecting position of each hook is positioned to allow the lever associated therewith to move immediately upon initiation of the movement of the draw hook when drawn by the draw knife.

The present invention relates to a dobby for effecting the programmed movement of the heald shafts on a weaving loom or machine; said dobby having means for sensing a programme carrier and for actuating auxiliary hooks; each auxiliary hook being associated with a draw hook and, depending on actuation or non-actuation, operating to determine a first or a second position of the draw hook associated therewith relatively to a draw knife.

In known dobbies, the auxiliary hooks moved by the feeler needles act, when they are actuated by auxiliary knives, on angle levers carrying support needles by means of which the draw hooks are raised or lowered. In a further known dobby, the auxiliary hooks act directly on support needles and displace the lower ends of the needles into or out of the path of movement of upwardly and downwardly moving riser knives. In the case of these known dobbies, the draw hooks bear on the support needles. In both cases, the draw hooks are actuated by the support needles, as the needles are moved perpendicularly with respect to the longitudinal axis of the draw hooks. At the same time, the support needles are, in their axial direction, loose machine parts which are disposed between the auxiliary hooks and the draw hooks. At high speeds, this condition, i.e., loose arrangement, often causes disturbances in the operation of the weaving machine.

The dobby according to the invention obviates these causes of breakdown. Furthermore, it reduces the number of transmission elements between the means sensing the programme carrier and the draw hooks and thus makes the operation of the arrangement more reliable.

According to the invention, each auxiliary hook is connected with a lever so that, when the auxiliary hook is actuated, it pivots the lever about its pivoting axis; the

3,393,? Patented July 2, 1968 pivoting axis being so arranged that one end of the lever travels along in engagement with the draw hook with which it is associated and, in one of the pivoting positions of the lever, it determines the first (or non-engaged) position of the draw hook whereas, in the other pivoting position, it determines the second .(or engaged) position thereof.

In the case of the above-mentioned, known dobbies having vertically arranged support needles, the return of the needles to their starting positions cannot take place until the draw hook has carried out a certain forward movement. The draw hook must be horizontal in the zone at which the support needle is in its supporting position. At a predetermined distance from this point, on the side remote from the draw knife, the draw hook is curved upwardly. Only when a draw hook engaged by a knife has moved for a distance such that its curved portion is located below the support needle is it possible to initiate the return movement of the needle in a upward direction. In contradistinction thereto, in the pres ent invention, due to the provision of a portion which projects from the draw hook and under which one end of the lever is disposed in the inoperative position, it becomes readily possible to insure that the restoring of the lever may begin simultaneously with the movement of the draw knife; since, under these circumstances, the lever which is traveling back is no longer able to contact the draw hook. In the case of high-speed machines, this small saving of time is a significant factor.

The invention will now be discussed in greater detail with reference to an example of embodiment illustrated in the figures of the drawings, wherein:

FIGURE 1 shows an example of a dobby having an arrangement according to the invention, and

FIGURE 2 shows a graphic illustration explaining the mode of operation of the arrangement of the dobby shown.

According to the perspective view shown in FIGURE 1, a punched card 12, forming a programme carrier, is guided over a cylinder 11. The presence or absence of a perforation in the card 12 determines the \positions of the heald shafts (not shown). The figure shows only a small portion of the width of the punched card 12. The card 12 is sensed by feeler needles 13 and 14. Of the feeler needles arranged in rows, only the foremost feeler needle of each row is shown. The needles 13 sense the even number picks and the needles 14 the uneven picks. Connected with each of the feeler needles 13 and 14 is one of the auxiliary hooks 15 or 16. As shown, auxiliary knives 17 cO-operate with the auxiliary hooks. The feeler needles 13 and 14 are adapted to be raised and lowered by means of the lifting rods 18 or 19. The knives 17 move either in the direction of the arrow A or in the direction opposite thereto.

When one of the auxiliary hooks 15 is actuated by drawing of one of the knives 17 in the direction of the arrow A, the two-armed lever 20, with which the auxiliary hooks 15 are connected, is rotated clockwise about its pivot 21. Analogously, in the event of actuation of one of the auxiliary books 16, by drawing one of the knives 17 in the direction of the arrow A, the two-armed lever 22 with which the auxiliary hooks 16 are connected, is rotated clockwise about its pivot 23. By means of the spring 24, the lever 20 is biased permanently against the stop 25 into its inoperative position and similarly the lever 22 is biased permanently by means of the spring 26 against the stop 27, into its inoperative position.

Due to the rotation of the levers 20 and 22, the draw hooks or lifters 28 or 29, respectively, are displaced into and out of the path of movement of the knives or griffes 30 or 31, respectively. The griifes 30 and 31 reciprocate in and opposite to the direction of the arrow B. The

hooks 28, 29 have the projecting portions 32 or 33, respectively. The draw hooks 28 and 29 are secured on the rocking lever 34. Lever 34 is mounted at the end of one of the arms 35 of a shaft lever rotatable about the pivot 36 which is-secured to the machine frame. The other arm 37 of the shaft lever is connected with a coupling to a heald shaft (not shown).

If none of the lifters 28, 29 is being drawn in the direction of the arrow B by one of the griffes 30, 31 the rocking lever 34 bears against the two stops 38 and 39 and the heald shaft not shown in the figure and coupled with the arm 37 is in its lower or inoperative position.

In operation, the individual rows of perforations in the punched card 12 indicated by the horizontal straight lines are sensed by the feeler needles. The rows of perforations corresponding to an even number pick and to an odd number pick follow each other alternatingly on the card. For the purpose of sensing, the rods 18 and 19 descend alternatingly, so that the needles 13 and 14- also descend. If a needle impinges in a perforation, it descends into the interior of the cylinder 11, otherwise it impinges against the material of the punch card and bears thereon. In the case of the working phase shown in FIGURE 1, the auxiliary hooks 15 secured to the needles 13 penetrating into the perforations in the punched card 12 descend until they bear on the knives 17, so that when the knives 17 move towards the left the auxiliary hooks 15 are carried with them. On the other hand, needles which bear on the card material do not allow the auxiliary hooks connected with them to descend to such an extent that they are engaged by the auxiliary knives.

In order that the arrangement may more readily be understood, the graphic illustration of FIGURE 2 shows the temporal development of the movements of the various parts. The time (as a phase angle) extending over two working cycles is plotted as the abscissa and the movements of the parts in respect to time are plotted as the ordinates. No exact scale accuracy has been observed. The curves illustrating the movements of the individual parts have been provided with the reference numerals given to the parts shown in FIGURE 1.

After the lowering, for example, of the rod 18, first of all the lower knife 17 moves towards the left and thereupon immediately again towards the right. During this time, the main griif 30 moves into its right-hand end position. While the lower auxiliary knife 17 moves back into its right-hand end position, the upper auxiliary knife 17 begins to move towards the left. At the instant at which the said upper auxiliary knife 17 again commences to return into its right-hand starting position, the main griff 30 begins to oscillate towards the left.

If, during the movement of one of the auxiliary knives 17 towards the left, one of the auxiliary hooks 15, the needle of which has descended into a perforation in the punched card 12, is carried towards the left, then lever 20 connected with the carried auxiliary hook 15 rotates clock-wise. The upper end 40 thereof is therefore drawn away from under the projecting portion 32 of the lifter 28, so that the latter descends on to the griff 30. During the movement of the gritf 30 towards the left, which now takes place, the lowered draw hooks, which no longer have a lever 20 disposed under them, of the row to which the draw hook 28 belongs are drawn towards the left.

Due to this drawing away of the hook 28, the rocking lever 34, which is carried by means of the pivot 36, via the shaft lever 35,37 is lifted off fromthe stop 38. Its center therefore moves toward the left. Consequently, the shaft lever 35, 37 and therewith also the arm 37, rotates about the fixed pivot 36. The free end of the arm 37 is thereby raised and therewith also the corresponding heald shaft, coupled thereto by means of a linkage (not shown).

During normal forward running of the weaving loom, the mode of operation described hereinabove, in connection with the lower knife 17, has no influence on the actual shaft movement, since the lower knife 17 returns into its right-hand position and therefore the moved-away lever 20 is again placed under the projecting portion 32, before the main griff 30 begins its movement towards the left. The purpose of this provision is to ensure that during the return running of the weaving loom, the shed movement takes place in exactly the reverse sequence relatively to forward running.

The mode of operation with regard to the sensing of the uneven picks by means of the needles 14, the transfer of the movement of the auxiliary needles 16 engaged by the knife 17 to the lever 22 and, by means of the free end 41 thereof and of the projecting portions 33, to the griff 29 is identical with that just described so that, in order to avoid repetition, this movement development will not be described in detail.

In the case of the example of the embodiment shown in FIGURE 1, rollers are secured at the end 40 of the lever 20 and at the end 41 of the lever 22. These ensure movement of the lever end 40 or of the lever end 41 along the draw hooks 28 or 29, respectively, with extremely little friction. However, the roller may also be omitted, in which case the lever ends 40 and 31 slide along their associated draw books 28 or 29, respectively. Of course, it is an essential feature that the travel curves for the ends 40 and 41 formed by the lifter 28, 29 and projecting portions 32, 33 are continuously curved.

According to a further embodiment, the projecting portions 32 or 33 respectively are not provided. In order to obtain an upward and downward movement of the lever ends which is of appropriate magnitude during the rotation thereof'from one of their end positions into the. other, it is with an embodiment of this kind expedient that the levers (inclusive of their two end positions) should remain at an acute angle relatively to the axis of the draw hook associated with them. An advantageous position is for example provided when the lever 20 bearing against the stop 25 is rotated clockwise relatively to the position shown in FIGURE 1 to such an extent that its axis forms an angle of 60 and with that of the hook 28. In an embodiment of this kind, the torque exerted by the weight of the draw hook 28 on the lever 20 is taken up by the spring 24.

The auxiliary hooks 15 and 16 are adapted to be pushed, from the side of the stops 25 and 27 and by means of their bent-over ends, over the retaining projections provided on the levers 20 and 22. If, then, the stops 25 and 27 (as shown in FIGURE 1) are designed as walls, then the stops prevent the moving-out towards the right of the bent-over parts, surrounding the projections, of the auxiliary hooks 15, 16.

The movement of the draw knives by means of levers pivotal about a pivot makes for a smooth and quiet mode of operation. Vibrations of the moved parts are avoided or at least greatly diminished.

While the novel features of the invention have been shown and described and are pointed out in the appended claims, it is to be understood that various omissions, substitutions and changes in construction and arrangement of the features shown and described may be made by those skilled in the art without departing from the spirit and scope of the invention.

What is claimed is:

1. A dobby for effecting a programmed movement of heald shafts on a loom, which comprises a program carrier, a plurality of auxiliary hooks, each being connected to a pivotable two-armed lever, said lever having a pivoting axis and being biased into an inoperative position against a stop by a pretensioning means, and upon actuation by an auxiliary hook being moved against the force of the pretensioning means to an operative position, means for sensing the program carrier and for actuating the auxiliary hooks in a programmed manner to pivot at least one of the pivotable levers about its pivoting axis, each of said pivotable levers being associated with a draw hook and, depending upon actuation or non-actuation by an auxiliary hook, being pivoted to the operative or inoperative position thereby determining an engaged or a non engaged position of the draw hook relative to a draw knife, each draw hook having a projecting portion extending therefrom, and the pivoting axis of each lever being arranged so that in one of its pivoted positions, the lever engages the projecting portion of the associated draw hook thereby positioning the draw hook in its non-engaged position and in the other pivoted position the lever moves away from the projecting portion thereby determining the engaged position oi the draw hook, one of the ends of the lever traveling in engagement along its associated draw hook during movement of the draw hook, and the projecting portion on each hook being positioned to allow the lever associated with the draw hook to move from its operative position to its inoperative position immediately upon initiation of the movement of said draw hook when drawn by said draw knife.

2. The dobby of claim 1 in which each of the auxiliary hooks are adapted to be moved into and out of a retaining arrangement on a lever from one side of the stop and the levers in their inoperative positions each abut against the stop, said stop constituting a wall whereby in the abutting position disengagement of the auxiliary hooks from the retaining arrangement is prevented by said wall.

3. The (lobby of claim 1 in which the draw hooks are arranged above the levers and supported thereby in a plane U extending perpendicularly with respect to the pivoting axes of the levers whereby pivoting of said levers quickly eifect raising and lowering the hooks.

4. The dobby of claim 3 in which the zone over which said one end of the lever moves along the draw hook forms a continuously curved travel curve.

-5. The dobby of claim 1 in which rollers are attached at said one end of the lever whereby said rollers roll along the draw hooks when the ends of the levers are moved.

References Cited UNITED STATES PATENTS 1,672,434 6/1928 Stambli l39-68 2,635,644 4/1953 Stambli et a1. 13963 2,705,505 4/1955 Stambli 13968 2,976,891 3/1961 Wicker 13971 FOREIGN PATENTS 624,838 9/1961 Italy.

942,474 11/ 1963 Great Britain.

221,907 9/ 1942 Switzerland.

HENRY S. JAUDON, Primary Examiner.

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