US3374682A - Rocker arm drive assembly for weaving apparatus - Google Patents

Description

March 26, 1968 MILANI 3,374,632

ROCKER ARM DRIVE ASSEMBLY FOR WEAVING APPARATUS Filed Oct. 20, 1965 INVENTOR.

LU/Gl M/LHNI MWWWM W United States Patent 3,374,682 ROCKER ARR I DRIVE ASSEMBLY FOR WEAVING APPARATUS Luigi Milani, Vanzaghello Magnago, Milan, Italy, assignor to Brevitex Etablissement pour lExploitation de Brevets Textiles, Vaduz, Liechtenstein Filed Oct. 20, 1965, Ser. No. 498,917 Claims priority, application Italy, Dec. 4, 1964, 26,048/64, Patent 743,819 3 Claims. (Cl. 7443) ABSTRACT OF THE DISCLOSURE A driving mechanism for operating the pawls which, in turn, operate the means for lifting the heddles of a dobbie of a loom, is disclosed as including a driven shaft rotated by the loom main shaft and having secured thereon a plurality of circular bushes. Each bush is operatively associated with a respective knife bearing arm for operating a pawl, and the center of each circular bush is offset radially from the axis of the driven shaft.

A plate is operatively associated with each bush and is formed with a circular opening rotatably embracing the associated bush, and each plate has a pivotal connection closely adjacent its circular opening and pivotally connecting the plate to a respective knife bearing arm at a point spaced from the pivotal mounting of the latter. Each plate thus forms a short crank rod for the associated knife bearing arm, and has an appreciable dwell time at dead center which assures secure engagement between its associated knife bearing arm and the associated pawl, for drawing the pawl, during rotation of the associated bush, without appreciable play.

Background of the invention This invention is related to a drive for the operating levers of the tie rods for the rocker arms that lift the hedclles in the dobbies.

According to the invention, the main object is to realin a device of the above referred to kind, suitable for obtaining a greater textile production, as well as a construction which is simpler and therefore less costly and more safely efficient, as compared to the known devices.

Known devices are essentially based upon means of kinematic transmission, which are represented by cams deriving their motion from the main shaft of the dobbie, and with reference to this lay-out, which calls for the use of means for the kinematic transmission to be used for lifting the heddles, said devices are quite slow and consequently the production of fabric is also affected. Besides, the use of cams calls for a rather accelerated wear of the moving elements, which makes necessary the replacement of said elements and therefore causes the stopping of the dobbie with consequent loss of production.

These and other difficulties are eliminated by the device, realized according to this invention, which is essentially characterized in that, for the drive of heddles, there is provided an eccentric mechanism of the rod and crank type, the said device being placed in correspondence of the forepart of the known arms (i.e. above the pattern-bearing cylinder), so as to drive the heddles by traction (and not by thrust) as in the already known instances, the kinematic linkage for transmitting the motion from the driven shaft of said device to the shaft of the pattern-bearing cylinder being obtained through at least one pair of oval or elliptical gears, of ratio equal to 1:1, the first of which is rigidly keyed upon the said driven shaft, while the second gear is used for transmitting the motion to a third gear which has the role of transmitting, through a suitable gear train, with the known ratio 1:8, the rotation of the shaft of the pattern-bearing cylinder.

Owing to the inventive concept now explained, the device realized according to this invention allows also for the abolition of the springing means used for keeping the followers in continuous contact with the contour of the driving cams, per se already known, up to now used in the devices of this kind.

The invention will now be more completely described with reference to one embodiment, being given only as an example and as shown in the enclosed drawing in which:

FIG. 1 shows a schematic elevation, on a reduced scale, exclusively limited to the arms with the relevant pawls as well as the operating levers of tie rods driven by the device, of a device according to this invention; and

FIG. 2 shows, also in elevation, the transmission device for the motion from the driven shaft to the shaft of the pattern-bearing cylinder.

With reference to the enclosed drawing, with a there are shown the lower arms and with b there are shown the upper arms, per se known, respectively fulcrumed in 1 and 2, which arms drive, with their ends 3a3b, the relevant knives 4a-4b, respectively the upper and lower ones. The knives 4a4b, fixed upon the arms 3a3b, respectively drive the pawls 5a and 5b, being the upper and lower ones, which are fulcrumed at 6 and 7 upon the yoke 8, itself pivoted with the follower 9 in the seat 10, formed by the hook 11 of levers c fulcrumed in 12 for operating the tie rods (not shown at the drawing) through the relevant arm 13 for lowering the heddles, said elements being per se known.

According to the invention, each of said arms a and b is driven through an eccentric mechanism comprising one rod, of which only one shall be described as they are identical, and for the similar elements of each one the same reference number shall be used, but followed respectively by letter a or b respectively if related to arm a or b.

Each rod and crank mechanism is formed by a bush 14a of circular cross section, having the .role of a crank, as the same is freely slid-ably lodged in a corresponding seat 15a formed in a plate 16a which acts as a rod, while upon the bush 14a there is provided one seat 17a, of center 0, which is eccentric with reference to center 0', of seat 15a of said bush 14a, but with parallel axis in order to receive, with a rigid keying, the shaft 18 which is the driven one, per se known, which is rotatably driven by the main shaft of the loom (not shown in the drawing). Said rod 16a, like a plate, is pivoted with its head 19a upon one pivot 20a, fixed on a projection 21a formed upon its arm a.

Identically for the second arm b which has a kinematic connection with shaft 18 through a similar bell and crank device, respectively formed by a plate 16b with its relevant eccentric bush 14b, together with other elements already described for arm a.

In such a way one obtains the operation of pawls 5a and 5b, and therefore the reciprocating oscillation of levers 0, driving the tie rods for lifting the heddles (not shown in the drawing).

The kinematic transmission for transmitting rotation from shaft 18 to the latter shaft 22 of the pattern-bearing cylinder 23 (not shown in the figures), is provided through a mechanism, as already said, formed by oval or elliptical gears. To this end (FIG. 2) upon the shaft 18 there is keyed an oval or elliptical gear 24 meshing with a similar gear 24', but staggered or angularly offset degrees with reference to gear 24. The said gear 24' causes the rotation, through a gear train 25 of shaft 22 upon which there is rigidly keyed the gear 26.

The gears now described are designed so that the transmission rat-io between shaft 18 and shaft 22 is made equal to 8:11.

With 27 and 28 there are shown the two known ratchets, respectively used for driving the rocker arms 2930, also known in themselves, and both fulcrumed at 31.

With 29' there is shown the end of rocker arm 29 which, when its cam loses contact with the relevant ratchet 27, has the function of lifting with its end 29 the pawl 5a placing the same in an inactive position.

Identically to the former case, with 30' there is shown the end of rocker arm 30 which, when it loses contact with its ratchet 28, lifts with its end 30' the pawl 5b, placing the same in the inactive position.

In order to simplify, on FIG. 1 there have been shown only two ratchets.

While a specific embodiment of the invention has been shown and described in detail to illustrate the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles. 7

What is claimed is:

1. In a dobbie for a loom including heddles, rocker arms for lifting the heddles, tie rods operatively associated with the rockerarms, operating levers for the tie rods, pawls operatively associated with the operating levers, pivotally mounted knife bearing arms for operating the pawls and a driven shaft driven by the loom main shaft; driving mechanism for said pawls comprising, in combination, circular bushes secured to rotate with said driven shaft and each operatively associated with the respective knife bearing arm, the center of each bush being offset radially from the axis of said driven shaft; and plates each operatively associated with a respective bush and formed with a circular opening rotatably embracing the associated bush, each plate having a pivotal connection closely adjacent its circular opening and pivotally connecting the plate to a respective knife bearing arm at a point spaced from the pivotal mounting of the latter; each plate thus forming a short crank rod for the associated knife hearing arm, and having an appreciable dwell time at dead center assuring secure engagement between its associated knife bearing arm and associated pawl for drawing the pawl during rotation of its associated bush without appreciable play.

2. In adobbie, driving mechanism, as claimed in claim 1, in which each knife bearing arm is a lever pivoted at one end and bearing a knife at its free end, and having an extension intermediate its ends pivotally connected to the associated plate at such pivotal connection of the latter. 7

3. In a dobbie, driving mechanism, as claimed in claim 1, in which each plate is oval-shaped in plan with a part of greater diameter formed with said circular opening and a part of lesser diameter having said pivotal connection.

References Cited UNITED STATES PATENTS 7 41,128 '1/1864 Snook 74570X 507,016 10/1893 Kuowlton et a1. 74-5-70X 1,826,318 10/1931 Lundgren 139'66 2,069,330 2/1937 Rossmann 139-,'66 2,143,236 1/1939 Bi'rk 74--437 X 2,781,800 2/1957 Papworth 7443 X FRED C. MATTERN, 111., Primary Examiner.

W. S. RATLIFF, Assistant Examiner.

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