CH639704A5 - Rotary thread guide for a spinning machine - Google Patents

Description

639 704

2

Claims (7)

1. Rotary thread guide for a spinning machine comprising a fixed support element, a casing, a hard material guide part through which the thread passes, a ball bearing whose inner and outer rings are secured respectively to the guide and of the casing, a permanent magnet mounted on a magnet support fixed to the guide part to allow the latter to be driven at a speed of rotation greater than that of the wire and a protective cover, characterized in that that the guide piece (1) is made in the form of a straight cylindrical tube having a substantially constant outer diameter over its entire length. 2. Wire guide according to claim 1, characterized in that the magnet support consists of a metal ring (5) driven onto the guide piece (1), the magnet (6) being fixed on the face bottom of the metal ring. 3. Wire guide according to claim 2, characterized in that the magnet is fixed to the underside of the metal ring (5) by gluing. 4. Wire guide according to claim 2, characterized in that the inner race (8) of the ball bearing (7) is clamped between the protective cover (11) driven onto the guide piece and a washer (10) in non-magnetic material resting on the upper face of the metal ring (5). 5. Wire guide according to claim 1, characterized in that the outer ring (9) of the ball bearing (7) is fixed to the housing (13) by riveting. 6. Wire guide according to claim 1, characterized in that the fixed support element consists of a clip (17) and that the housing (13) has on its periphery a circular groove (16) receiving the branches of said clips. 7. Wire guide according to claim 1, characterized in that the guide piece is made of ceramic. The invention relates to rotary yarn guides for spinning machines. A rotating thread guide has the function, in a spinning machine, of guiding the thread in line with the axis of the spindle and of rotating it to give it an additional twist. This torsion gives the yarn greater resistance, which reduces breakage during its manufacture. The rotating wire guide has a tubular guide piece through which the wire passes. This guide piece is made of a very hard material, for example ceramic, to prevent wear or polishing of the hole through which the wire passes. The guide piece rotates around its axis at a speed of rotation greater than that of the wire thanks to a ball bearing bearing between it and the support of the wire guide and to a permanent magnet with which it is integral and which is driven by another magnet carried by the pin. The external shoulders and bearing surfaces presented by the guide parts in known wire guides make it difficult to machine them. Grinding which would make it possible to obtain low tolerances is practically excluded for reasons of cost price. We are therefore content to obtain wide tolerances for the outer diameters of the guide part and the other elements of the wire guide are fixed on the guide part, using intermediate parts, such as cages, by gluing. . However, fixing by gluing increases the assembly time, reduces the concentricity of the elements and makes it practically impossible to replace a part, in particular the ball bearing. The object of the invention is to produce a yarn guide that does not have these drawbacks. This object is achieved thanks to the fact that, in the wire guide according to the invention, the guide piece is made in the form of a straight cylindrical tube, having a substantially constant outer diameter over its entire length. It is then possible to inexpensively grind the guide part to obtain very small tolerances on its outside diameter, which makes it possible to drive out other elements of the wire guide on the guide part and, consequently, to simplify assembly of the thread guide. This also makes it possible to use smaller, and therefore less expensive, ball bearings than in known thread guides, hence reducing friction. Furthermore, in known devices, the support is welded to a casing in which the outer ring of the ball bearing is glued. The thread guide is fixed by screwing the support onto the spinning machine while carefully adjusting the coaxiality of the guide with respect to the spindle. It is therefore necessary to carry out the same screwing and adjustment operations each time the wire guide is changed, periodic replacement being necessary due to the limited life of the ball bearing. This other drawback is avoided in one embodiment of the wire guide thanks to the fact that the support is constituted by a clip and that the casing has, on its periphery, a circular groove intended to receive the branches of the clips. The characteristics and advantages of the yarn guide according to the invention will become apparent during the following description of an embodiment with reference to the appended drawing in which FIGS. 1 and 2 represent respectively a sectional view and a front view of the yarn guide according to the invention. The wire guide according to the invention comprises a guide piece 1 made in the form of a straight, cylindrical tube, made of a hard, sintered material, such as ceramic, in which the wire 2 passes. the outside, has rounded edges 3 and 4 to prevent deterioration of the wire. An iron ring 5 constituting the magnet support and serving as a magnetic screen is driven onto the guide piece 1. The permanent magnet 6 for driving the guide piece in rotation is glued to the underside of the metal ring 5. The wire guide also comprises a ball bearing 7 threaded onto the guide piece 1, the inner ring 8 of which is pinched between a washer 10 of non-magnetic material, resting on the upper face of the metal ring 5, and a bearing surface. 12 of a protective cover 11 driven on the guide piece. The washer 10 keeps the ball bearing 7 at a distance from the metal ring 5 to avoid friction between the magnet support 5 and the outer ring of the bearing. This method of fixing the ball bearing 7 makes it possible to avoid compression of its cage which would occur if the bearing were driven onto the guide part and which would cause a reduction in the play of the balls and would therefore reduce the "lifespan bearing. The wire guide further comprises a casing 13, made for example of brass, assembled by riveting to the outer ring 9 of the ball bearing and two shims 14,15 to make the ball bearing dustproof. These shims 14,15, in the form of thin rings, have their outer edge clamped between the outer ring 9 of the ball bearing and the housing 13 and their inner edge which bears respectively on the bearing surface 12 of the protective cover 11 and on washer 10. Furthermore, the casing 13 has on its periphery a circular groove 16 intended to receive the two branches of a clip 17 constituting the fixed support element of the thread guide. This clip fastening makes it possible to change a defective yarn guide quickly and without tools and, consequently, to shorten the downtime of the spindles of the weaving machine, thus making it more profitable. 5 10 15 20 25 30 35 40 45 50 55 60 R 1 drawing sheet