Seam protecting device for drum grinding or raising machines

Abstract: The present invention relates to a seam protecting device which can be applied to drum grinding or raising machines, for preventing threads connecting adjoining pieces to be processed from breaking, characterized in that the device comprises at least a pair of ring-like elements (1), parallel to one another and connected by means of connnecting beams or bars, adapted to turn about bearings (2) and a drum (3) provided with raising or grinding cylinders (4). To the pair of ring-like elements there is applied a cusp element (8) which, under a normal condition, is located at the bottom part of the drum.

Description: BACKGROUND OF THE INVENTION The present invention relates to a seam protecting device, designed for application to drum grinding or raising machines, for preventing threads connecting pieces to be processed from accidentally breaking. As is known, the drum raising and grinding machines conventionally comprise cylinder means for driving the fabric to be processed. More specifically, with respect to the raising machine, the fabric is continuously supplied to a drum including several raising cylinders, on the surfaces of which there are provided a plurality of teeth which raise the surface of the fabric, by exerting a pulling action on the fibres forming the several threads. In the grinding machines, on the other hand, the drum is provided with grinding cylinders, coated by abrasive strips, which subject the fabrics, preferably of cotton, lap, microfibre of silk type, to a suitable grinding or sanding action, so as to provide the fabric with a peach peel effect. Both in the raising operation and in the grinding operation, the fabric is subjected to great mechanical stresses which cause the cotton or nylon threads used for connecting to one another two adjoining pieces to break. At present, for overcoming the above mentioned drawback, the two above mentioned machines are provided, at the driving cylinders thereof arranged upstream of the drum, with a sensing element to detect the presence of seams. This sensor, however, upon sensing the presence of seams, resets to zero the raising or grinding speed of the cylinders located on the drum, which usually turn about themselves. Thus, a comparatively long length of the fabric piece is not processed, and it must be rejected, with a consequent great damage from the yield standpoint. The document US-A-50 84 948 discloses in column 16, lines 8-30, a seam detector enabling to control the operating parameters of a napping machine. SUMMARY OF THE INVENTION Accordingly, the aim of the present invention is to overcome the above mentioned drawbacks, by providing a seam protecting device, for application to drum grinding or raising machines, adapted to prevent threads connecting adjoining pieces to be processed from accidentally breaking, which device is also adapted to process the portion of the fabric arranged near fabric seams, without causing any breakages of the cotton or nylon threads used for mutually connecting two adjoining pieces. Within the scope of the above mentioned aim, a main object of the present invention is to provide such a device which is very reliable and safe in operation, can be easily made by using easily commercially available elements and materials and, moreover, is very competitive from a mere economic standpoint. According to one aspect of the present invention, the above mentioned aim and objects, as well as yet other objects, which will become more apparent hereinafter, are achieved by a seam protecting device, as claimed in the main claim. BRIEF DESCRIPTION OF THE DRAWINGS Further characteristics and advantages of the invention will become more apparent hereinafter from the following detailed disclosure of a preferred, though not exclusive, embodiment of a seam protecting device, for application to drum grinding or raising machines, adapted to prevent threads connecting adjoining pieces to be processed from accidentally breaking, which is illustrated, by way of an indicative, but not limitative example, in the accompanying drawings, where: Figure 1 is a front view of a grinding machine including the device according to the present invention; and Figure 2 is a front view of a raising machine also including a device according to the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to the number references of the figures of the accompanying drawings, the seam protecting device, for application to drum grinding or raising machines, and specifically designed for preventing threads connecting adjoining pieces of fabric to be processed from being accidentally broken, comprises at least a pair of ring-like elements, indicated at the reference number 1, which are parallel to one another and connected by connecting beams or bars. These ring-like elements can turn about bearings 2 and a drum 3, including raising or grind-cylinders 4. The fabric 7 to be processed by the cylinders 4 is supplied in a continuous manner to said drum by means of suitable driving cylinders 5 therewith there is associated a sensor 6. To the pair of annular elements 1 there is applied a cusp element, indicated at the reference number 8, which, under a normal condition, is arranged at the position A, shown in figure 1, for the grinding machine and at the position B, shown in figure 2, for the raising machine. To each of said machines, moreover, there are associated two cylinders, indicated at the reference number 9, including corresponding brush elements 10, the bristles or metal coatings of which are specifically designed for cleaning the raising or grinding cylinders. In operation, as a seam is sensed by the sensor 6, there is started the counting operation of a pulse counting device for perfectly timing the displacement of the seam with that of the cusp element 8. This cusp element, accordingly, has a peripheral rotary speed with respect to the drum 3 which is equal to the fabric advancement speed, thereby the cusp element 8 is always held under the seam which, accordingly, will be not subjected to any mechanical raising or grinding actions. More specifically, the peripheral rotary speed of the cusp element 8 can be controlled through a three-phase AC motor, driven by an inverter, or by a brushless electric motor or, if desired, by a DC electric motor or by means of an electronic type of speed varying device. The above mentioned cusp element, moreover, in addition to protecting the seamed regions thereunder it is arranged, will simultaneously cause the seamed regions to be separated from the cylinders 4, as it is clearly shown in figures 1 and 2. With respect to the grinding machine, the cusp element 8, after a rotation through 360° about the drum 3, will be stopped at the starting position A, waiting for the subsequent seam. With respect to the raising machine, on the other hand, the cusp element 8, after a rotation about the drum 3 to the position C, will be stopped and caused to reverse its turning direction, thereby returning to its starting position B, waiting for a new seam. From the above disclosure it should be apparent that the invention fully achieves the intended aim and objects. The invention, as disclosed, is susceptible to several variations and modifications, all of which will come within the scope of the inventive idea. Moreover, all of the details can be replaced by other technically equivalent elements. In practicing the invention, the used materials, provided that they are compatible to the intended use, as well as the contingent size and shapes can be any, according to requirements.

Claims: A seam protecting device, for application to a grinding or raising machine of the type including a drum and raising or grinding cylinders, said device being adapted to prevent threads connecting adjoining pieces of fabric from breaking, characterized in that said device comprises at least a pair of parallel mutually connected ring-like elements (1) one of said rings being located on a side of said fabric and the other of said rings being located on the other side of said fabric and being adapted to turn about bearing means (2) and said drum (3), to said rings being applied a cusp element (8), extending transversely of the entire length of said fabric, said cusp element (8) having its vertex directed towards the inside of said fabric so as to cause the seamed regions thereof to be separated from said cylinders (4) of said grinding or raising machine, thereby protecting said seamed regions. A seam protecting device according to Claim 1, characterized in that said cusp element (8), under a normal condition, is arranged at a bottom portion of said drum (3). A seam protecting device according to Claims 1 and 2, characterized in that said cusp element (8) can turn through 360° about said drum (3). A seam protecting device according to one or more of the preceding claims, characterized in that said cusp element (8) is caused to rotate about said drum (3) through nearly 360°, and then it being stopped and the turning direction thereof being reversed. A seam protecting device according to one or more of the preceding claims, characterized in that said cusp element (8) has a turning peripheral speed about said drum (3) equal to the advancing speed of the fabric on said drum (3). A seam protecting device according to one or more of the preceding claims, characterized in that the turning peripheral speed of said cusp element (8) is controlled by a three-phase motor, driven by an inverter, or by a brushless motor, or by a DC motor or an electronic speed varying device.

Inventors: CROSTA EMANUELE, CROSTA, EMANUELE
Applicants: CROSTA MARIO SRL, MARIO CROSTA S.R.L.
Application year: 1993
Main classification: D06C11
IPC codes: D06C11