US2904078A - Dobby for weaving looms with positive movement with one or two cylinders for cards - Google Patents

Description

p 15, 1959 G. PELLIS 2,904,078

DOBBY FOR WEA G LOOMS WITH POSITIVE MOVEMENT WITH ONE TWO CYLINDERS FOR CARDS Filed May 28, 1954 3 Sheets-Sheet 1 l I I f/oVAnm PELLIS Sept. 15, 1959 G. PELLIS 2,904,073

' DOBBY FOR WEAVING LOOMS WITH POSITIVE MOVEMENT WITH ONE OR TWO CYLINDERS FOR ems Filed Kay 28, 1954 3 Sheets-Sheet 2 nm'mu a L\ .l]

[I o o I I: v 22 I] H Q. 5 i 2 J E a a g I I a a 5% 2:; a 0

INVENTOflz- Q flow/mm Pit-L13 Sept. 15, 1959 G. PELLIS 2,904,

DOBBY FOR WEAVING LOOMS WITH POSITIVE MOVEMENT WITH ONE OR TWO CYLINDERS FOR CARDS Filed May 28, 1954 3 Sheets-Sheet 3 I/VVENTOR? QOl/HNN) FELL/3 United States Patent DOBBY' FOR WEAVING LOOMS WITH POSITIVE MOVEMENT WITH ONE OR TWO YLINDERS FOR CARDS Giovanni Pellis, Gorizia, Italy Application May 28, 1954, Serial No. 432,989" Claims priority, application Italy June. 1, 1953* i 3 Claims; (Cl. 139-77) The dobby described briefly here departs in its new conception from the aforementioned characteristics, and eliminates all the disadvantages complained of.

Its characteristics are as follows:

(a) All the controls of the drive mechanism are positive;

(b) Minimum encumbrance and convenient supervision and application of the cards;

(.c) Absence of return springs. and thus reliability of operation;

(d) Control by means of chain transmission directly from a shaft of the loom;

(e) Location of the dobby on a supporting bracket at floor level connected with the shoulder of the loom, and thus elimination of vibrations;

(1) All the contrivances are hermetically enclosed in a casing and operate in an oil bath.

In the attached sheet of drawings, Figure 1 represents part of a dobby, drawn partly in elevation and with some members in section; Figure 2 shows in section a modification of a detail; Figure 3 is a general elevational view of a representative loom on which the dobby is mounted; Figure 4 is a sectional view taken along a line transverse to the longitudinal axis of the cylinder 1 in Figure 1.

Referring to Figure 3, the loom illustrated includes the usual healds which are movable up and down, with respect to a general frame structure 31 of the loom, by conventional cranked levers 32 coupled by thrust rods 33 to the arm 20 of a treadle of the dobby. The dobby as a whole is situated at the left-hand side of Figure 3, and is illustrated in and described in detail with respect to Figures 1 and 2. A drive for the sprocket 24 in Figure 1 is obtained in the usual way by a chain 34 coupling it to a sprocket 35 on the usual main shaft 36 of the loom.

Referring now to Figures 1 and 2, the dobby includes a shaft 2, on which the sprocket 24 is keyed, and which carries keyed thereon a scroll cylinder 1 having in its cylindrical surface a scroll groove 27 in which is engaged a cam follower consisting of a roller 6 mounted on a segment 5 provided with peripheral rack teeth and pivoted on a shaft 4. As the cylinder 1 rotates, the helicoidal scroll groove therein causes oscillation of the segment 5 about its pivot shaft 4. The rack teeth of the segment 5 mesh with the teeth of a relatively elongated cylindrical drum 7 having the teeth arranged along the whole of its length. As the segment oscillates, the drum revolves alternately in one end the other direction. Above the "ice drum. are disposed vertically slidable racks 8 which are: guided between guide rollers 12 and a rack pinion. 9 which is permanently meshed. therewith. Each rack, in its uppermost. rest position (as illustrated) is out, of en. gagement at its lower end with thev drum 1. Each rack. carries at its'lower end a detent 13 pivotedv at 281 thereona for movement between a first position inwhich its; toothv will engage with the teeth of the drum 1, anda second position: wherein. its tooth is clear of and will not be, engaged by the teeth of the drum- 1. The position of en, gagementv or disengagement of. the detent 13 is controlled. as follows. It will be appreciated that an exactly similar arrangement is: provided foreach of theracks, 8-, but only the right hand. one is illustrated, for clarity of. the drawing. The end walls of the: cylinder 1 are each provided with an eccentric camming groove'3, in. which is engaged a. cam follower consisting of a roller 18 onan arm, 19. The arm 19 is one arm of a cranked lever pivoted on the machine frame. As the arm 19 is rocked by cam action, the other arm 19a moves upand down about the pivot. This other arm 19a is coupled at its free-end to the bridg member 15 which can slide vertically. During, each full rotation of the: cylinder 1, each bridge member 15 is lifted and lowered once, the. two being operated 180? out of phase; On each bridge member 15 is. mounted pivota-hly a: rocker 16 the lower end of which is engaged into arecess in the top of the detent 13. Thelower face of. the bridge member 15 has a knife edge 14 adapted to seat into, corresponding recesses provided in the top surface of: the detent, thereby to positively lock. the. latter into whichever position it becomes set. The bridge. membersare alternately rising and fallingv and as they do sotheycause the rockers 16 to engage atone side or the: other ofa preselector cam 17 rockably mounted toabut against stop block 10-and under they control. of a rod 22 moved longitudinally intoraised and lowered position by the usual control system for the dobby, eg. a punched-card device: of conventional nature. Thus, according. to the position, of thepreselector 17 determined bythe: pattern, formation. control device of the dobby,v the. rocker 16", when it is raised, will have its top end moved to right or left as the case may be, whereby the lower end thereof will drive the detent 13 into or out of engagement with the teeth of the drum 7. Longitudinal movement of the control rods 22 thus determines whether or not the respective rack will be caused to reciprocate by engagement with the drum 7, or not. Between the racks is engaged the pinion 9, which is carried at the end of a link 21 connected to one arm of a cranked treadle rockably mounted on a pivot 26, the other arm 20 of the treadle being coupled to the heald in the manner described above.

When the rack 8 has reached the end of its upward travel, the tooth of the detent 13 remains in engagement with the drum 7 and the detent can either remain engaged and cause the subsequent descent of the rack 8, or be disengaged from the drum 7 by action of the rocker 16. A bar 11 is provided on the drum 7 and is in fact a tooth thereof but made somewhat longer than the other teeth, as will be most clear from Figure 4 of the drawing. At the end point of rotation of the drum 7, as in Figure 2, the bar 11 engages against the underside of the rack 8 and presses the rack as a whole upwardly against the stop rod 25 (see Figure 2). This momentarily relieves the detent .13 of any frictional engagement with the teeth of the drum 7, and the detent can thus be more readily disengaged if required.

In operation, if the control rods 22 are both kept in raised position, neither of the racks 8 are moved, and the arm 20 of the treadle remains in the position illustrated in Figure 1, i.e. in which the heald is lowered. If-

one control rod 22 is raised, and the other remains lowered, one rack will be engaged with the drum 7 and the other not engaged therewith, so that the pinion 9 will perform a rolling movement, between the racks, of amplitude half that of the length of movement of the moving' rack. When both control rods 22 remain in lowered position, both' racks are engaged and moved byv the drum 7, whereby the pinion 9 assumes an intermediate position shown in broken line in Figure 1, wherein the ann'zo of the treadle is' moved into another position indicated in broken line in Figure 1, causing the heald to be held in raised position.

The pinion 9 assumes this intermediate position because, whenthe two detents 13 are engaged with the racks 8 at opposite sides of the drum 7, the two racks 8 are compelled to make equal and opposite movements. As the pinion 9 is meshed with both racks it will assume the intermediate position. The pinion 9 is only moved upwards or downwards out of this intermediate position when one of the racks remains stationary whilst the other. moves by reason of engagement with the drum.

' In the modification shown in Figure 2, the pivoted detent 13 of Figure 1 is replaced by a horizontally slidable block 29 provided with a detent for engagement with the drum 7, and operated by exactly similar mechanism to that described precedingly.

I claim e I 1. In a loom dobby, means for causing lifting and lowering movement of a heald comprising a frame for the loom,atwo-arm treadle lever pivotably mounted on the frame, means for linking one arm of said treadle lever to a heald, a link pivotably connected to the other arm of the treadle lever, a toothed roller rotatably mounted on the link, a pair of spaced parallel racks permanently meshed with the toothed roller and longitudinally slidable with respect to the frame, a toothed driving drum rotatably mounted in the frame adjacent one end of the two racks when said racks are in rest position, means for rotary reciprocation of said driving drum, detent means movably mounted on each rack and arranged to be movableinto an engaged position in which they engage with the driving drum to mesh the rack with the driving drum and cause longitudinal movement of the respective rack, and a disengaged position wherein they are disengaged from the driving drum, and means for selectively moving one or the other or both of said detent means into engaged position.

2. In a loom dobby, means for causing lifting and lowering movement of a heald, as claimed in claim 1, wherein the means for rotary reciprocation of the driving drum comprise a rack-toothed segment pivoted on the frame and-meshed with the driving drum, a driven scrollcylinderrotatably mounted in the frame and having a scroll groove cut therein to serve as an axially-acting cam, and a cam-follower roller rotatably mounted on the toothed segment and engaged in the scroll groove of the cylinder so as to rock the segment as the scroll cylinder rotates.

3. In a loom dobby, means for causing lifting and lowering movement of a heald, as claimed in claim 2, wherein means for selectively moving one or the other or both of the detent means into engaged position, comprise a bridge member foreach detent slidably vertically on the frame,

an arm coupled to each bridge member, a cam follower roller on each arm, a cam channel provided in each of the two end faces of the scroll cylinder and having said cam follower rollers engaged therein, the shape of such channels being arranged such that the bridge members References Cited in the file of this patent UNITED STATES PATENTS 240,009 Crompton Apr. 12, 1881 240,304 Crompton Apr. 19, 1881 1,877,759 Atwood et a1. Sept. 20, 1932 FOREIGN PATENTS 967,981 France Apr. 5, 1950

Images