The present invention relates to a method for stopping and positioning an equipment piece born on board of a mobile service carriage performing a continuous reciprocating patrolling motion along a side of an operating machine and furthermore to a device for practicing this method.
As disclosed in DE-A-35 36850, DE-A-21 17585 and EP-A 124 151, to date, in the automation of textile machines, the mobile service carriages have been exactly positioned by resorting to pin means, or to fork means, or to means having similar shapes. Said mobile carriages support and house maintenance and/or operating equipment pieces. In the case where pin means are used, a push actuator drives the extension of a mechanical pin which, by getting engaged into one of a series of bores provided on a plate rigidly fastened onto the framework of the machine, makes it possible the mobile carriage to be locked in its working positions. The so carried out positioning and locking unavoidably generates vibrations, of uncontrollable intensity, on the structure of the mobile carriage, with said vibrations being also transferred to the whole equipment piece on board of the same carriage. Said equipment piece submitted to more or less intense vibrations will be damaged, at least in its precision members, such as, e.g., detector and position sensors, as well as operating arms and lever systems. These latter will come to operate in their movements along incorrect coordinates, in that their supports may result to be more or less deformed owing to the repeating impacts generated by the sudden stops of the mobile carriage.
In the case where fork means are used, an actuator actuates the extension of the prongs of the said fork, engaging them to surround one of a series of protruding elements rigidly fastened to the framework of the machine.
Also in case of such a positioning and locking means, more or less intense vibrations are triggered as well, and the same above mentioned operating drawbacks will therefore occur. Furthermore, the fork must be associated to the presence of a tooth, or latch, capable of ensuring the carriage stopping lock during the whole time period of intervention of the equipment piece borne by said mobile carriage. The structure of the fork locking means is therefore not simple.
The purpose of the present invention is of overcoming the above mentioned drawbacks, by providing a stopping and positioning method, by means of which the mobile carriage can be stopped at precise working positions, without considerable vibrations being generated and transmitted on the supported equipment piece borne by said mobile carriage. The method of the invention is characterized by the features indicated in the characterizing part of claim 1. In order to practice this method, a device in conformity with claim 2 is used.
This device has a simple structure, and makes it also possible a reliable precision to be achieved over time, in that it is neither damaged nor worn during the operations; and, thanks to its structural simpleness, it is also very reliable in operation, and not sensible to dirtying effects. This device is associated with means known from the prior art for the automatic monitoring and detection of the positions wherein the equipment piece supported by the saddle must perform its action, with said service carriage running along rail guides provided along the working front(s) of an operating machine, such as, e.g., a ring spinning frame. Inasmuch as said service carriages used for the automatic intervention for the splicing of broken threads on continuous spinning frames equipped with ring rail, and the equipment pieces associated with them, as well as the relevant operating members, including their system for programmed control, have structural features known from the prior art, they do not need to be herein explained in detail.
Forms of practical embodiment of the device according to the invention are defined in claims 3 to 5.
In the hereto attached drawing table, an example of practical embodiment of the invention is shown in a schematic view, and exclusively as regards those parts which need to be explained.
The figure of the drawing table shows a top plan view of a device according to the present invention, with the sensors which are required in order to enable the mobile carriage speed reducing system; it should be observed that these sensors are not represented in their details, in that they are inside the knowledge of those skilled in the art.
In the drawing, we have that:
The following disclosure of the operation, made by referring to the attached figure, concerns solely the device according to the present invention, which carries out the stopping and positioning of the mobile carriage bearing an equipment piece for the automatic maintenance of one or several machine front(s). It is understood that, for it to operate, detecting means and complementary devices are necessary, which are known per se and not herein discussed.
It is known to associate to a textile machine, such as e.g. a ring spinning frame, a service carriage in order to automatically re-join the broken threads during the spinning spindles operation. Said carriage is caused to run along the spinning front(s), along running ways comprising one or several rail(s) of any shapes, cooperating with suitable rolling means such as wheels, or rollers, or equivalent means. During the operation of the spinning frame, the service carriage for the re-joining of the threads is continuously frontally reciprocated along the spindle bed, performing a reciprocating patrolling motion.
During said patrolling monitoring, the traveling carriage detects, by using detecting means known from the prior art, whether the thread is present or not on each spinning spindle. When it detects the absence of one of the threads under way of formation, the detecting means in cooperation with the proximity sensors 1 of inductive type, as well as through the operating program, enables the actuation of an electrovalve which makes the pneumatic actuator 7 start to operate via the stem 5 and push the block 2 to its position 2a, coming into frontal interference with the protruding element 3 which comes before the space into which the same block 2 has to pushed (see the attached figure).
The anticipated advancement of the block 2 relatively to the space it should enter, inside which it will be locked at the end of the positioning step, is necessary because the same block 2, by means of its frontal surface, carries out a useful braking action, in order to reduce the speed of the whole carriage during the step of passage from the steady-state patrolling speed to the reduced speed of positioning beginning. It should be observed that the inertia of a mobile carriage carring on board one or several equipment piece(s) is difficult to evaluate with correctness. With this latter specific statement in mind, the device according to the present invention carries out an adjustable braking effect, by varying, with known means, the intensity of the frontal thrust applied by the block 2 to the protruding element 3 by means of the actuator 7.
When, at the end of the front sliding, the contact begins between the inclined section 4 of block 2 and the circumferential surface of the element 3, the block 2 frontally moves to reach its position 2b. At this time point, it is advantageous that a microswitch (not shown), entrusted with the task of detecting this frontal movement, disables and stops the carriage drive motor. The front thrust generated by the actuator 7, the inclined section 4 of the block 2 and the circumferential surface of the element 3 make it possible, owing to the shape of their contact surfaces, the positioning block 2 to be automatically and gradually wedged into the space it must enter in order to ensure the precise alignment of the traveling equipment piece with the spinning spindle, around which the working units advance and operate. The preservation of the precise alignment obtained, throughout the necessary time period for the above mentioned operating actions, is ensured by the surface sections 6 of the positioning block 2. Any fortuitous translating forces are in fact nullified by the planar contact between the surfaces 6 and the protruding elements 3.
It is clear that the present invention proposes a method and a device suitable for positioning and stopping a mobile carriage traveling along the operating front of operating machines, without causing considerable impacts and vibrations which, should be present, would damage the equipment pieces, or equipment piece parts, carried on board by said carriage.