Sliding link for a dobby lever

Abstract: A sliding nut (20) for a dobby lever of a textile loom, which can be inserted into a main lever (11) which consists of a pair of parallel flat sides (12,13), separate but fixed to each other, where the sliding nut (20) comprises a body which can be inserted between the sides (12,13), at one end of which is a hole (22) suitable for receiving a joint which can be connected to a driving bar and at the other end a relative blocking device for the sides, the body being shaped at the second end (25) to receive sloping surfaces on which there are wedge-shaped elements (28), in a complementary slanting position, which can be inserted into a box-shaped container (30) and acting upon the sides, a screw element (34) being applicable to the box as a blocking device to determine the performance of the wedge-shaped elements (28) with respect to the sloping surfaces and sides at the main lever.

Description: The present invention relates to a sliding link for a dobby lever. In presently known fast textile looms, rotating dobbies are used in which a driving rod corresponds to each frame, activated by a rotating cam. The driving rod, in turn, controls a regulating lever for transmitting movement to the lifting equipment of the frames of the loom. The stroke is regulated according to the position of the frame with respect to the formation point of the fabric and this stroke variation can be obtained by moving the sliding links situated on the suitably shaped body of the lever and equipped with devices for blocking the position with respect to the lever. In looms which use bulky levers in a single piece, the sliding link has a cavity which is connected to and runs on the lever. This cavity should have a matching clamping screw, acting as a blocking device, which enables the steady positioning of the sliding link on the lever. This screw is not very accessible to the operator when it is being used to block the sliding link. In addition the sliding link must be inserted on the lever, at a free end of the same, and there must be a certain free space in the dobby for both the assembly and disassembly operation, which causes greater encumbrance. A proposal has also been made for improving the structure of a dobby lever and relative sliding link and this solution is claimed in Italian patent 1.229.284 filed by the same applicant, which discloses a sliding link according to the preamble of claim 1. In this patent, a particular composite lever is described, with two parallel sheared plate sides, joined by a ring-shaped hub which acts as a fulcrum for the lever, and a damping spacer unit which is bolted in correspondence with a free end of the sides. In this way a hollow part is formed between the two sides in which a sliding link is inserted which, by regulating its position inside the lever, allows the variation of the lifting of the frames. However, even for removing the sliding link such as the one described, illustrated and claimed in the above Italian patent, for example in a maintenance phase of the machine, the damping spacer block must also be removed. This entails removing the bolts situated at the free end of the sides. This operation, apart from requiring a certain amount of time, may cause an alteration in the planarity between the two sheared plates of the sides, with subsequent difficulty in the reassembly phase in re-establishing the exact position. It is also evident that to pull out the sliding link from the upper part of the sides of the lever, freed from the damping spacer block, it is also necessary to have a certain amount of additional space in an area immediately above the lever to be able to carry out the operation. The present invention seeks to provide a sliding link which overcomes these problems and which can be particularly used in a control lever of the two-sided type. The invention further seeks to provide a sliding link which does not require the disassembly of the lever parts, with a consequently more limited encumbrance in the entire dobby with respect to the present. According to the invention, there is provided a sliding link for a dobby lever of a textile loom, the link being of the type which can be inserted into a main lever which comprises a pair of parallel flat sides separate but fixed to each other, wherein the sliding link comprises a body which can be inserted between the sides of the main lever and having a hole at one end for receiving a joint which can be connected to a driving bar and a relative blocking device at the other end for the sides of the main lever characterised in that the body has sloping surfaces at said other end on which there are wedge-shaped elements with complementary slanting surfaces, which elements can be inserted into a box-shaped container together with said other end when positioned and act upon the sides of the main lever, the sliding link further comprising a screw element insertable into the box as a blocking device to determine the movement, or wedging of the wedge-shaped elements with respect to the sloping surfaces and the sides of the main lever. With this kind of sliding link there is therefore the possibility of an extremely easy and convenient assembly with respect to the main two-sided lever. In addition, the particular structure of the sliding link according to the invention allows a more compact sizing and limited encumbrance of the entire dobby. The particular form of the blocking devices of the sliding link avoids the disassembly of the main lever or part of it for the assembly and/or removal of the sliding link. The invention will now be described in greater detail, by way of example, with reference to the drawings, in which:- Figure 1 is a partial perspective view of a main lever for a dobby on which a sliding link according to the present invention is assembled, wherein the sliding link is shown in a first assembly position; Figure 2 is a partial perspective view completely similar to fig. 1 with the sliding link illustrated in a second assembly position; and Figure 3 is an exploded perspective view of the sliding link alone according to the present invention. With reference to the figures, a general illustration is given of a main lever 11, or part thereof, of a rotating dobby, which as is known can have its fulcrum on the shaft supported by a fixed part and which is driven by a relative rod, not shown herein. The main lever 11 consists of a pair of flat parallel sides 12 and 13, made for example of calibrated plate, obtained by shearing. The two flat sides 12 and 13 are firmly held on to each other by a ring-shaped spacer hub inserted between them and blocked by tightening in the press, in which the shaft supported by the fixed part is positioned. A vibration damping-spacer unit 14, for example fixed by rivets or bolts 16 to the sides 12 and 13 of the lever, is then inserted between the sides 12 and 13 of the lever in an upper part of the end of the main lever 11. A sliding link 20 according to the present invention, is assembled on to the main lever 11. The sliding link 20 comprises a shaped body having an enlarged end 21 with a hole 22 suitable for receiving a joint not shown and for example comprising a bearing and relative pin with which it is hinged and connected to a driving rod, which activates by levers or equivalent devices, the frames of the textile loom, not shown in the figures, for example similar to those partially illustrated in the Italian patent 1.229.284 mentioned above. The enlarged end 21 has two shaped ledges 23 adaptable to the curved profile of the main lever formed by the two sides 12 and 13, whereas it also has possible shaped seats 24 for receiving the end of the above mentioned driving rod. The central portion of the body of the sliding link 20 is thinned and linked to a second T-shaped end 25. This second T-shaped end 25, in the part facing the central portion of the sliding link, has two slanting surfaces or parts joining it. In the upper portion instead there is a rounded surface 27 connecting the free ends of the two slanting surfaces 26. The sliding link 20 has blocking devices which comprise a pair of wedged-shaped elements 28, having a complementary shape and slant with respect to the slanting surfaces 26. This pair of wedge-shaped elements 28 is held together by means of an elastic connecting element 29, which prevents the accidental separation of the elements 28. In this way, both the slanting surfaces 26 and connecting element 29 form a group which can be positioned on the second T-shaped end 25. A box-shaped element 30 can be inserted onto the second end 25 of the body of the sliding link 20 once the two wedge-shaped elements 28 have been positioned on the slanting surfaces 26 and held by the connecting element 29, so as to complete the blocking device of the sliding link. The box-shaped element 30 comprises, for example, a sheet 31, U-folded to form the two sides or lateral walls thereof. These sides are fixed to each other by end-blocks 32 inserted between them and fixed by rivets 33 or similar blocks. In one of these end-blocks 32 there is a threaded bore, not shown, in which a blocking screw 34 of the sliding link with respect to the main lever on its lateral configuration, can be inserted and positioned. This screw acts between the box-shaped element and the relative block and determines the movement, or wedging with respect to the sloping surfaces of the second end 25 of the body of the sliding link. Although it is possible to obtain the body of the sliding link with the opening 22 in line with the longitudinal axis A, in the embodiment illustrated the body of the sliding link has the first enlarged end 21 in an eccentric position with respect to the axis A. It is possible, also with this eccentric conformation, with a sliding link according to the present invention, to have a reverse/upside-down assembly. This possibility of a different assembly is clearly shown in figures 1 and 2. This possibility allows, with the same range of the sliding link 21 in the lever 11, a greater variation in the span of the frame. As a result, there is a reduced encumbrance of both the lever and the sliding link. This is also possible as the second T-shaped end 25 of the body of the sliding link can be placed in the box-shaped element in a couple of positions so that the regulating screw always acts correctly in an upward position. In this way the operator can block the sliding link on the main lever in the position which is necessary for obtaining the desired span of the frame. The blocking of the wedge-shaped elements can also be carried out in both of the positions of the second end 25 of the wedge body because the blocking action takes place either on one wedge or another, as these are inserted in the box-shaped element which keeps them in the correct position with respect to the second T-shaped end of the body of the sliding link. The particular inclination of the slanting surfaces 26 and facing surfaces 26 1 of the wedge-shaped elements 28, for example of between 20° and 45°, permits the development of blocking forces between the sliding link and the main lever which are actually double with respect to the known art without slanting surfaces. In addition, this inclination also favors the release of the strain of the parts, and it automatically causes the reopening of the wedge-shaped elements. For this purpose, as is clearly shown in figure 3, it can be seen that each of the wedge-shaped elements 28 has a seat 35, which widens towards the inside, and which is suitable for receiving the enlarged ends 36 of the connecting element 29. From the opposite part of these wedge-shaped elements 28 facing the sides 12 and 13 and at the open part of the sheet 31 the wedge-shaped elements have enlargements 37 which provide ledges for these. In addition, as illustrated for example in the same figure, it can be seen how the connecting element 29, in one form of embodiment which is not limiting, can consist of an elastic plate. It is easy to understand that the sliding link of the present invention can be assembled without removing the vibration-damping spacer unit situated at the end of the main lever. In fact, by removing the blocking screw from its clamping position on the side of the configuration of the main lever, the box-shaped element can be removed from above the wedges placed in their operating position. It is subsequently possible to remove the wedges themselves, by extending the connecting element between them. Finally, the body of the sliding link can be pulled out from the cavity situated between the two sides of the main lever. It is therefore not necessary for the main lever to be involved at all in the disassembly and in this way it does not lose its correct conformation, obtained for example by leveling, after the assembly operation, the two sides by means of the ring-shaped spacer hub and the vibration-damping spacer unit. Any possible need for the reconstruction of the planarity of the main lever is therefore eliminated and this also acquires greater stability. The controls are consequently reduced to a single control in the first assembly phase of the main lever. The elimination of the necessity existing in all the control levers of the previous art of having to pull the sliding link out of the end equipped with the vibration-damping spacer unit, also has other advantages. A first advantage lies in being able to lower the upper limit of the machine making it more compact, which is extremely advantageous in looms or textile machines where there is an enormous quantity of mechanisms and controls. A second advantage lies in being able to shorten the control lever with a further saving of space, as well as, as a consequence, of materials and operations.

Claims: A sliding link (20)for a dobby lever of a textile loom, the link (20) being of the type which can be inserted into a main lever (11) which comprises a pair of parallel flat sides (12, 13), separate but fixed to each other, wherein the sliding link (20) comprises a body which can be inserted between the sides (12, 13) of the main lever (11) and having a hole (22) at one end for receiving a joint which can be connected to a driving bar and a relative blocking device at the other end (25) for the sides (12, 13) of the main lever (11) characterised in that the body has sloping surfaces (26) at said other end (25) on which there are wedge-shaped elements (28) with complementary slanting surfaces (26 1 ), which elements (28) can be inserted into a box-shaped container (30) together with said other end (25) when positioned and act upon the sides (12, 13) of the main lever (11), the sliding link (20) further comprising a screw element (34) insertable into the box (30) as a blocking device to determine the movement, or wedging of the wedge-shaped elements (28) with respect to the sloping surfaces (26) and the sides (12, 13) of the main lever (11). A sliding link according to claim 1, characterized in that said wedge-shaped elements (27) are held together by a connecting element (29) which can be freely joined to them. A sliding link according to claim 2, characterized in that said connecting element (29) has elastic properties. A sliding link according to claim 1, 2 or 3 characterized in that the said other end is T-shaped and the sloping surfaces (26) are directed towards a central portion of the body. A sliding link according to claim 2 and any claim dependent directly or indirectly thereon, characterized in that the said other end of the body of the sliding link is thinned and linked to a central portion of said body, and in that said other end has a connecting zone between the two sloping surfaces (26) on which the connecting element (29) is joined. A sliding link according to claim 5, characterized in that the connecting zone is complementary to the connecting element (29). A sliding link according to any preceding claim, characterized in that the wedge-shaped elements (27) have a seat (35) for each end of said connecting element (29). A sliding link according to any preceding claim, characterized in that the box-shaped container (30) comprises a U-folded sheet (31) having lateral parts fixed to each other by blocks (32) inserted between them and held by blocking devices. A sliding link according to claim 8, characterized in that the blocking device comprises a screw (34) inserted in a threaded hole of one of said end blocks (32). A sliding link according to any preceding claim, characterized in that said body of said sliding link (20) has a longitudinal axis and in that the hole (22), is positioned eccentrically with respect to said longitudinal axis.

Inventors: ALTAMORE MASSIMO, GRIFONI FRANCESCO, ALTAMORE, MASSIMO, GRIFONI, FRANCESCO
Applicants: NUOVO PIGNONE SPA, NUOVO PIGNONE S.P.A.
Application year: 1995
Main classification: D03C1
IPC codes: D03C1