EP0882821A1

EP0882821A1 - Programming device for rotary dobbies in weaving machines

Info

Publication number: EP0882821A1
Application number: EP98110019A
Authority: EP
Inventors: Gian Luigi Cremonesi
Original assignee: FIMTEXTILE SpA
Current assignee: FIMTEXTILE SpA
Priority date: 1997-06-03
Filing date: 1998-06-02
Publication date: 1998-12-09
Anticipated expiration: 2018-06-02
Also published as: DE69819405D1; DE69819405T2; EP0882821B1

Abstract

Device for performing the programming of rotary dobbies for the operation of head frames in weaving machines, of the type in which the operating levers (3) of the head frames are actuated by connecting rods (2) each mounted on an eccentric ring (5) rotating with respect to the main shaft (1) of the dobby which comprises moreover a disk (13) made to rotate by said shaft (1) and an engaging lever (7) pivotably mounted on said eccentric ring (5) and apt to engage with said disk (13) via its end tooth (11) under the action of a spring (12). The device comprises a lever (14) with projecting end profiles (14a, 14b) for controlling the engaging lever (7), in which the two projecting profiles are provided with a tooth (14a, 14b) pivotably mounted in a recess having two diverging abutting walls (14x, 14y) and kept in contact with one of them (14x) by a spring (14d), and/or a rocker (28) of the engaging lever (7) comprising a seat (30) for engagement and locking with a pin (2c) integral with the corresponding connecting rod (2).

Description

The present invention relates to a selector device for performing the programming of rotary dobbies for actuating the head frames in weaving looms.

It is known that the positioning of the heald frames of a weaving machine or loom, from which the configuration of the finished fabric is obtained, must be programmed in accordance with a predetermined sequence which defines the position which each frame must assume upon each rotation of the main shaft of the loom.

So that the shed formed by the warp yarns can open and close alternately, allowing the weft yarn to be inserted, the heald frames must correspondingly assume a high position and a low position, drawing with them during this movement the corresponding warp yarns. In order to transform the rotary movement of the main shaft into an alternating translatory movement of the frames, a weave machine and, in particular, "dobbies" are used, in which suitable eccentrics control the movement of the respective frames by means of lever mechanisms.

The upward and downward movement of the head frames must be able to be programmed so that, at each half turn of the main shaft, the individual frame may be kept in a high position, in a low position or displaced from one position to another. To achieve this, the corresponding eccentric must be idle with respect thereto, to keep the associated frame immobile, and alternately must be joined to the main shaft, to move the frame itself: the selection device apt to perform this programming operation forms precisely the subject of the present invention.

In the art devices for programming dobbies are known, said devices, however, having numerous drawbacks including the need to operate at the right time and with extreme precision the components responsible for selection of the desired state, for example in order to stop the shaft at each half-turn, so as to have the necessary time to cancel the previous selection and set a new one for the next half-turn. It is obvious how programming devices of this type cause an increase in the idle time of the machine, to the detriment of the useful working time. This is even more critical especially in the modern weaving looms where the rates reached are of the order of several hundreds of cycles per minute and hence the selection and operating times must necessarily be very brief.

Another type of drawback which can be encountered in the devices of the art consists in the high probability of errors which arise from the fact of performing a selection in a "punctual" manner in the middle of the motion curve. In order to understand this problem more fully, reference will be made to Fig. 1 of the accompanying drawings, in which, by way of example, the evolution of a reference angle on the main shaft of the loom as a function of the time and the corresponding displacement of a theoretical selector (a) and of a selector of the known art (b and c) is shown. As can be seen, the theoretical selector reaches its maximum displacement, which corresponds to the operation of disengaging the engaging member which joins together the eccentric and the main shaft, at a singular point of the curve (apex of the curve (a)): this would be possible only if the contact between the selector and the engaging member were able to occur in a punctual and instantaneous manner. It is obvious that this condition cannot be realized in practice, both because the engaging member requires a discrete time in order to engage and disengage the eccentric and the main shaft from one another and because operation would be too critical depending on the play and the constructional tolerances.

Furthermore, the attainment of this theoretical condition is also complicated by the need to perform the same operations also during reverse running of the loom (a motion condition which is often used during maintenance of the loom and repairing of the broken yarns). In order for the selector to be able to operate in a symmetrical manner during forwards and reverse running - as in the curve (a) - acting substantially instantaneously on the engaging member, it would in fact be necessary for both these elements to interact by means of two respective pointed parts: a goal which would be difficult to achieve in practical terms since the mechanical components must in any case interact with each other by means of discrete surfaces.

It perhaps hardly needs to be mentioned that the selection errors are reflected in errors in the insertion of the weft, thereby resulting in time lost in order to stop the loom, restore the preceding conditions and restart operation, taking suitable measures to prevent the fabric being formed with apparent defects.

However, the possibility which is to be feared most is that selection may occur in a precarious manner. In this case, if engagement between the members responsible for selection should not occur during movement of the frames, there could be a sudden release of the frames themselves which, dropping downwards, would result in irregular closure of the shed with inevitable interference and possible impact with the members for inserting the weft yarn.

In order to avoid all these said drawbacks, according to the most recent known art, the control member, which joins the eccentric to the main shaft, consists of an engaging lever, fixed to the eccentric, having an engaging tooth which is alternately engaged with or disengaged from a recess formed in a member fixed to the main rotational shaft, so as to engage and disengage, respectively, the eccentric with/from the main shaft. The engaging lever is formed in the manner of a profile in the form of a cam with which the end of C-shaped controlling lever interacts. In this way, the end of the controlling lever may be brought into the trajectory of the engaging lever in advance of the arrival of the lever itself, since the cam profile ensures that the pressing action thereon, and the consequent disengagement of the engaging tooth, is performed gently. It is possible, therefore, to perform these operations in a more gradual manner - rather than being obliged to slow down brusquely rotation of the main shaft (with consequent sudden acceleration motion laws) so as to give the operating lever the opportunity to intervene in a punctual and precise manner on the engaging lever - also allowing for a certain amount of tolerance in the precision of the device.

Locking of the engaging lever, both in the position where the engaging tooth is extracted from its recess (frame idle) and in the position where the tooth is engaged (frame which varies its position), is moreover ensured by means of a small stud which is fixed to a connecting rod and which engages in a corresponding recess on an end of the lever itself.

However, the drawbacks associated with the inevitable imprecision which still exists during selection remain. The constructional and mounting tolerances cannot be nominally respected; moreover, the friction of the cam profiles results in wear which adversely affects, with use, the operating precision; finally, the need to perform the same selection during both in the forwards running and reverse running results in the need to resort to compromises in the design, to the detriment of precision.

Firstly, locking of the engaging lever on the pin is still critical: insertion of the latter into its seat must be performed with a high degree of reliability in order to prevent selection from occurring in a precarious manner.

A solution proposed in the known art consists in providing a resilient mounting assembly for the pin on the connecting rod. Although this solution, in the case of inevitable operating imprecision, reduces the risk of the pin not entering correctly its seat, catching on the end of the engaging lever - with the possibility of accidental disengagement and consequent drop of the corresponding head frame - it is still not without defects and is complex to implement.

In EP-0,485,009, on the other hand, operating imprecision is overcome by providing a second cam portion on the engaging lever, in the region of the seat into which the locking pin engages. This solution makes it possible to obtain a safe selection of the engaging lever, in the extracted position or in the engaged position, keeping the constructional tolerances within an acceptable range. However, operation is still not entirely satisfactory. In fact, the trajectories followed by the end of the engaging lever and - ultimately also those of the cam portion of the pin seat - cannot be always precisely designed and are in any case variable depending on the direction of running of the loom and the wear phenomena, so that the cam surfaces do not always manage to function in an optimum manner.

A second category of drawbacks arises from the need to perform an equivalent selection both during forwards running and during reverse running of the loom. Normally the cam profile of the engaging lever is designed to perform a correct engagement and disengagement motion of the engaging tooth during forwards running of the weaving loom, while it is difficult to obtain the same thing for reverse running of the loom itself. In fact, since a punctual interaction between two mechanical components (the engaging lever and the end of the controlling lever) cannot occur, inevitably the interaction will take place correctly in one direction (for example during forwards running of the loom) and in advance in the opposite direction (for example during reverse running of the loom), thus resulting in an operational phase-shift.

In fact, as can be seen in the graph (b) of Fig. 1, forwards running occurs along the

line

1, 2, 3, 4. If, however, reverse running were to occur along the

same line

4, 3, 2, 1, there would be a phase advance sf during the active operation at point 3, and hence likely faulty catching of the engaging lever.

To avoid these problems, according to the known art a double actuator or a double operating phase actuator is used, so as to cause the end of the C-shaped controlling lever to interfere with the trajectory of the engaging lever at different times for forwards running and for reverse running. In particular, during reverse running, actuation of the controlling lever must occur with a phase delay sf so as to follow the

line

5, 6, 7, 8 of the graph (c) of Fig. 1, where the active operation occurs at 6, i.e. in phase with the active operation 2 of forwards running. However, the double actuator is a delicate component which is difficult to program and costly.

The double actuator remains indispensable in the solution proposed in the Italian Patent Application No. MI95A002037, in which a further improvement has been obtained by providing one end of the controlling lever with an oscillating profile. This solution solves, however, only partially the abovementioned problems of phase-displacement between forwards running and reverse running.

All the drawbacks highlighted above are overcome in a satisfactory manner by the device according to the invention, the innovative characteristics of which are described in the accompanying claims.

Further characteristic features and advantages of the device according to the invention will appear, however, more clearly from the detailed description which follows of some preferred embodiments thereof, provided by way of example and illustrated in the accompanying drawings, in which:

Fig. 1 is a diagrammatic view which shows, as already mentioned above, the operational graphs of the selector device;

Figs. 2 and 3 are schematic, partial, cross-sectional views showing a rotary dobby to which a first embodiment of the device according to the invention is applied, in a position at the start of a half-turn and in a following position, with changing of the position of the frame, respectively;

Figs. 2A and 3A are views similar to those of Figs. 2 and 3, at the end of the half-turn during forwards running and in a following position, with the position of the frame being maintained, respectively;

Figs. 2B and 3B are views on a larger scale, similar to the preceding ones, at the end of the half-turn during forwards running, before the start of disengagement of the engaging lever and after disengagement thereof has been completed, respectively;

Figs. 4, 5 and 6 are views similar to those of Figs. 2B and 3B, at the end of a half-turn during reverse running, which show in detail operation of the device according to the invention;

Figs. 7 and 8 are schematic views, with parts partially removed, of a second embodiment of the selection device according to the invention shown complete during changing of the position of the heald frame;

Figs. 7A and 8A are views which are similar to those of Figs. 7 and 8 and which show the selection device during disengagement of the engaging lever;

Fig. 9 is a side elevation view, on a larger scale, of the engaging lever according to the invention;

Fig. 10 is a side elevation view of a variation of embodiment of the engaging lever according to the invention, enlarged on the same scale as in Fig. 9; and

Figs. 11 and 12 are views which are similar to those of Figs. 7 and 8 and which show another embodiment of the selection device according to the invention.

As illustrated in the drawings, the device according to the invention forms part of a dobby which comprises a rotating shaft 1 onto which there is mounted a connecting-rod element 2 shaped so as to have a projection 2a pivotably mounted at 3a on the operating rod 3 of the corresponding heald frame (not shown) and a substantially circular ring 2b on which two pins 2c are mounted in opposite positions.

A bearing 4 is provided in a central position on the connecting rod 2, on the inner race of the bearing being mounted an eccentric cam 5 being able to rotate, as can be seen further below, with respect to the shaft 1.

On the eccentric cam 5 there is pivotably mounted, by means of a rivet 6 or the like, a rocker arm lever 7, or engaging lever, which has shaped ends 8 and 9, a seat 20 and an engaging tooth 11 on the inner side opposite to the end 9.

A spring 12 arranged between the eccentric cam 5 and the end 9 of the lever 7 exerts a recall action on the lever 7 itself and thus tends to cause it rotate so as to move the tooth 11 towards the axis of rotation of the shaft 1.

A disk 13, finally, is keyed coaxially on said shaft 1, on the periphery of said disk there being formed two

recesses

13a and 13b which are arranged diametrically opposite one another with respect to the centre of rotation of the disk 13 itself.

On the disk 13 there is keyed the inner race of a bearing, on the outer race of which the eccentric cam 5 is mounted so as to thus rotate about the shaft 1.

The disk 13 has the same lie as the lever 7 so that the tooth 11 of the latter is able to engage with one of the two

recesses

13a or 13b and disengage therefrom.

In the embodiment shown in Figs. 2 to 6, the dobby is completed by an controlling lever 14, which is C-shaped and the ends of which, according to the invention, are equipped with respective movable projecting profiles in the form of

teeth

14a and 14b which oscillate between abutting

walls

14x and 14y and are kept in position against the former of said walls by springs 14d.

The controlling lever 14 oscillates about a pivot 14c between a first position, defined by the biasing force of a spring 15 and by an abutment element 16, and a second position defined, according to the invention, by the thrust exerted by a sole programming actuator 17 or single operating phase actuator, the action of which is schematically indicated by means of an arrow A.

The dobby operates as follows: at the start of the half-turn of the shaft 1 (Fig. 2) and in the case of forwards running and programming effected with a view to varying the position of the frame, the actuator 17 does not exert any action on the lever 14, which, being subject to the action of the spring 15, abuts against the element 16, thus leaving the rocker-arm engaging lever 7 subject to the recall action of the spring 12, with the tooth 11 engaged in the recess 13a.

In this situation the eccentric 5 is integrally joined to the rotating disk 13 which, rotating together with the shaft 1 during the half-turn (Fig. 3), draws with itself in rotation the eccentric 5 and hence the connecting rod 2 which, rotating, also draws the operating lever 3 of the frame, causing it to change position.

According to the invention, before the half-turn has been completed (Fig. 3), the programming device 17 pre-sets the control action relating to the next half-turn, namely in the example in question in view of keeping the frame in the previous position. It does not exert, therefore, any action on the controlling lever 14, and the tooth 14b, when it comes into contact (Fig. 2A) with the rear surface 8a of the end 8 of the engaging lever 7, formed with a rising front face, forces the lever 7 itself, continuing the rotation of the disk 13, to rotate about its rivet 6, causing the tooth 11, which is provided at the opposite end, to gradually come out of the recess 13a of the disk 13.

Once the dead centre of the half-turn has been reached (Fig. 2A), the engaging lever 7 is totally rotated outwards and engaged with the pin 2c via its seat 20, while the tooth 11 is totally extracted from the recess 13a.

The eccentric cam 5 thus remains idle with respect to the disk 13, thus resulting in the previous position of the head frame controlled by the lever 3 being maintained during the next half-turn (Fig. 3B).

Figs. 2B and 3B illustrate in detail how the engaging lever 7 is controlled during the stages of operation of the device according to the invention described above, in the forwards running condition.

Figs. 4, 5 and 6 show, on the other hand, in the same detail, how the engaging lever 7 is controlled during the corresponding stages of operation of the device in the reverse running condition. As can be deduced from the illustrations, the step of engagement of the tooth 14b of the controlling lever 14 with the engaging lever 7 takes place, in accordance with the invention, in such a way as to provide a phase-displacement sf in the rotation of the shaft 1 with respect to the phase in the forwards running condition, equivalent to the idle stroke which the engaging lever 7 performs before bringing the tooth 14b into abutment against the wall 14y. This takes place owing to the particular system of assembly of the tooth 14b which is able to oscillate, against the action of the spring 14d, between the abutting wall 14x and the abutting wall 14y. Since the spring 14d exerts an action which is weaker than that of the spring 12 which biases the lever 7 against the disk 13 (or, in any case, the effect of the former never exceeds that of the latter), when the tooth 14b engages with the end 8a of the lever 7 in the reverse running condition (Fig. 4), the lever 7 does not undergo any displacement, whereas the tooth 14b oscillates (Fig. 5).

The phase-displacement sf makes it possible to compensate for the fact that the interaction between the lever 7 and the tooth 14b is not "punctual" and would therefore occur at two different points for forwards and reverse running, resulting in the loss of selection equivalence between these two motion conditions.

According to the invention, also the opposite end 14a of the controlling lever 14 operates in a manner similar to that just described, the two ends being apt to select the idle condition of the head frames respectively at the top dead centre and bottom dead centre of the operating rod 3 which acts on the frame itself.

In this way, the programming actuator 17 is always able to intervene in the same manner, both in order to position the end 14a and to position the end 14b, no longer having to ensure a separate synchronised selection for forwards running and for reverse running of the loom.

The solution illustrated hitherto is totally innovative and fully solves the problems of the known art. In particular, it ensures a very gentle selection action, drastically reduces the deceleration dead time for performing selection itself and eliminates the need for the double operating phase actuator.

Here it is worth considering more closely this last advantage. It must be said in fact that the inventors have conducted their research in an area where the use of double operating phase actuators was consolidated - a prejudice which for a long time prevented the attainment of the advantageous solution proposed by the present invention, which is simple, but at the same time very effective and free from malfunctions.

In the embodiment of the device which is shown in Figs. 7 to 10 and which, similar to the preceding embodiment as regards the general structure, a rocker arm lever 7, or engaging lever, is mounted pivotably on the eccentric 5 by way of a rivet 6, or the like, and has a shaped rear end 8 and front end 9 from the opposite side of which an engaging tooth 11 projects.

A spring 12 arranged between the eccentric 5 and the end 9 of the lever 7 exerts a recall action on the lever 7 itself and thus tends to cause it to rotate so as to move the tooth 11 towards the axis of rotation of the shaft 1.

A disk 13, finally, is mounted onto said shaft 1, coaxially therewith, and has formed on its periphery two

recesses

13a and 13b which are arranged diametrically opposite with respect to the centre of rotation of the disk 13 itself.

On the disk 13 there is mounted the inner race of a bearing, on the outer race of which the eccentric 5 is mounted so as to thus rotate about the shaft 1.

The disk 13 has the same lie as the lever 7 such that the tooth 11 of the latter is able to engage with one of the two

recesses

13a or 13b or disengage therefrom.

The dobby is completed by an controlling lever 14 which is C-shaped and the ends of which are formed with

suitable profiles

24a and 24b.

The controlling lever 14 oscillates about a pivot 14c between a first position, defined by the pulling force of a spring 15 and by an abutment element 16, and a second position defined by the thrust exerted by a programming actuator, the action of which is schematically indicated by means of an arrow 27.

According to the invention, moreover, the engaging lever 7 (Figs. 9 and 10) is provided with a cam-type rocker 28 mounted pivotably on the lever 7 by means of a pin 28a. The rocker 28 is kept in a rest position by a locating element 29 and by a spring 29a. In order to allow engagement of the lever 7 with the locking pin 2c, a seat 30, intended to receive the pin 2c itself, is formed on the upper portion (in the Figures) of the rocker 28.

In the embodiment shown in Fig. 9, the pivot pin 28a of the rocker coincides with the rivet 6 of the lever 7. In this case, the locating element 29, which is integral with the rocker 28, urges, as a result of the action of the spring 29a, against a tooth 7a formed on the front end 9 of the engaging lever 7.

In the embodiment of Fig. 10, the pivot pin 28a is arranged instead on the end 9 of the lever 7. In this case the locating element 29 abuts, again as a result of the action of the spring 29a, against the outer edge of the lever 7.

The inherent resilient oscillating movement of the rocker 28 ensures that the pin 2c is securely inserted into the seat 30 even in the event of an imprecise approach movement of the two elements, owing to the rocker 28, on which the seat 30 is formed, being apt to adapt itself locally around the pin 2c.

The dobby - in the case of the embodiment according to Figs. 7 to 10 - operates as follows: at the start of the half-turn of the shaft 1 (Fig. 8) and in the case of forwards running and programming effected with a view to varying the position of the frame, the programming device 17 does not exert any action on the lever 14 which, as a result of the action of the spring 15, comes into abutment against the element 16 and, not causing interference of the end 24b with the lever 7, leaves the latter subject to the recall action of the spring 12 which keeps the tooth 11 engaged in the recess 13a.

In this situation, the eccentric 5 is integrally joined to the rotating disk 13 which, rotating with the shaft 1 during the half-turn (Fig. 8), draws in rotation the eccentric 5 itself and hence the connecting rod 2 which, oscillating, draws the operating rod 3 of the frame, causing it to change position.

Before the half-turn has been completed (Fig. 8), the programming device 17 pre-sets the controlling action relating the next half-turn, namely in the example in question keeping the frame in the previous position. It does not exert, therefore, any action on the lever 14, and the end 24a thereof, when it comes into contact (Fig. 7A) with the surface of the rear end 8 of the engaging lever 7, formed with a rising front face, forces the lever 7 itself, continuing the rotation of the disk 13, to rotate about its rivet 6, causing the tooth 11 to come out gradually from the recess 13a of the disk 13.

According to the invention, as the lever 7 rotates about its rivet 6 under the action of the end 24a of the controlling lever 14, the rocker 28 moves towards the pin 2c, until the latter is received in the seat 30. When small phase-displacement errors occur in the movement, the possibility of resilient adaptation of the rocker 28 against the pin 2c ensures that no faulty catching of the two elements occurs (something which could give rise to an irregular escaping movement of the tooth 11 from the recess 13a and to the drawbacks mentioned above) and therefore produces perfect engagement of the lever 7 with the pin 2c.

Once the dead centre of the half-turn has been reached (Fig. 7A), the engaging lever 7 is totally rotated outwards and engaged with the pin 2c, while the tooth 11 is totally extracted from the recess 13a.

The eccentric 5 thus remains idle with respect to the disk 13 and integrally joined, by means of the lever 7 and the pin 2c, to the connecting rod 2, this resulting in the previous position of the heald frame controlled by the rod 3 being maintained during the next half-turn (Fig. 8A).

For the sake of brevity, operation has been illustrated referring only to the end 24a of the controlling lever 14, but it is evident that the same type of actuation may occur at the end 24b of the controlling lever 14, the two ends being apt to disengage the eccentric 5 from the main shaft 1 each at one of the top dead centre, or bottom dead centre, of the head frame.

A further embodiment of the invention is illustrated in Figs. 11 and 12. Here the two

ends

34a and 34b of the controlling lever are still provided with resiliently oscillating

teeth

34x and 34y, which operate in a manner similar to that of the resiliently oscillating teeth of the first embodiment of the device (Figs. 2 to 6).

The oscillating

teeth

34x and 34y allow the cam end 8 of the lever 7 to be operated in an equivalent manner both during forwards running and during reverse running of the loom. The combination of this structure of the controlling lever 14, which is able to act gradually and symmetrically on the rear end 8 of the lever 7, with the oscillating rocker 28, apt to ensure secure locking of the lever 7 with the pin 2c, improves further the operational reliability of the entire selection device.

With the device described and illustrated, in fact, the present invention ensures selection and blocking of the position of the heald frames, avoiding any possible faulty catching during this stage both during forwards running and during reverse running of the loom.

It is understood that other practical embodiments of the invention which are different from that described and which legitimately fall within the protective scope of the present invention, as will be obvious to persons skilled in the art, may be possible.

Claims

Device for performing the programming of rotary dobbies for the operation of the heald frames in weaving machines, of the type in which the operating levers (3) of the head frames are actuated by connecting rods (2) each mounted on an eccentric ring (5) rotating with respect to the main shaft (1) of the dobby, which comprises moreover a disk (13) made to rotate by said shaft (1) and an engaging lever (7) pivotably mounted on said eccentric ring (5) and apt to engage with said disk (13) by means of its end tooth (11), as a result of the action of a spring (12), said device comprising a controlling lever (14) rotating about a fixed pivot (14c) under the action of thrusting means (17) and against spring-type recall means (15) so that projecting end profiles (14a, 14b) of the said controlling lever (14) are arranged alternately along or outside the trajectory of the end (8) opposite to the toothed end of the engaging lever (7) so as to produce or avoid engagement thereof with the rotating disk (13), the pivoting of the controlling lever (14) being performed during rotation of the main shaft, said engaging lever (7) having moreover a seat (20, 30) for engagement with pins (2c) of the connecting rod (2), characterized in that both the projecting end profiles of said controlling lever (14) are provided with a tooth (14a, 14b) pivotably mounted on the corresponding end of said lever (14) in a recess having two diverging abutting walls (14x, 14y) and kept in contact with one (14x) of them by a spring (14d) so as to be able to oscillate until it makes contact with the other wall (14y), in order to phase-displace active engagement with said engaging lever (7) in the reverse running condition of the dobby, and in that said thrusting means (17) consist of a single operating phase programming actuator.
Device according to Claim 1, in which the spring acting on the engaging lever (7) and the spring acting on the toothed profile (14a, 14b) of the controlling lever (14) are dimensioned so that the effect of the former cannot be exceeded by that of the latter.
Device according to Claim 1 or Claim 2, in which an oscillating cam (9a) is pivotably mounted on one end of said engaging lever (7) opposite the end tooth (11), subject to the action of a spring (9b), said cam (9a) being apt to engage with a locking pin (2c) integral with the body of said connecting rod (2).
Device for performing the programming of rotary dobbies for the operation of head frames in weaving machines, of the type in which the operating rods (3) of the head frames are actuated by connecting rods (2) each mounted on an eccentric ring (5) rotating with respect to the main shaft (1) of the dobby which moreover comprises a disk (13), made to rotate by said shaft (1), and an engaging lever (7) pivotably mounted by means of a rivet (6) on said eccentric ring (5) and apt to engage with said disk (13) by means of its end tooth (11), under the action of a spring (12), said device comprising a controlling lever (14) rotating about a fixed pivot (14c) as a result of the action of thrusting means (27) and against spring-type recall means (15) so that projecting end profiles (24a, 24b) of the same controlling lever (14) are arranged alternately along or outside the trajectory of an end (8) of the engaging lever (7) so as to prevent or produce the engagement thereof with the rotating disk (13), said engaging lever (7) having moreover a seat (30) for engagement with pins (2c) integral with the respective connecting rod (2), characterized in that said seat (30) is formed on a rocker (28) pivotably mounted on said engaging lever (7).
Device according to Claim 4, in which said rocker (28) is kept in its rest position by the combined action of a spring (29a), acting between the rocker (28) and the engaging lever (7), and a locating element (29) which comes into contact with the edge of said engaging lever (7).
Device according to Claim 5, in which the rocker (28) is pivotably mounted on said engaging lever (7) by means of a pin (28a) which coincides with the rivet (6) for rotation of the lever itself on the eccentric (5).
Device according to Claim 5, in which the rocker (28) is pivotably mounted on said engaging lever (7) by means of a pin (28a) arranged on the front end (9) of the engaging lever (7).
Device according to any one of Claims 4) to 7), in which both the projecting end profiles (24a, 24b) of the controlling lever (14) comprise resiliently oscillating teeth (34x, 34y).