Abstract:
An insulating apparatus for the application of a nonadhesive insulating tape (15) to the winding of an electric coil (8) comprises a first pressure head (2) for receiving an adhesive tape (9) and the non-adhesive insulating tape (15). In an alternative embodiment a second pressure head (18) is located above the first pressure head (2) and faces the latter; both pressure heads being displaceable from a rest position into a working position. The adhesive tape (9) is fed from a supply roll (10) over a stress relief device (11) and the nonadhesive insulating tape (15) is fed from another supply roll (16), with both tapes (9, 15) being held by suction on a support surface of the corresponding pressure head (2 or 18). Each pressure head (2, 18) is equipped with a blade (3 and 4) for the cutting of the tapes (9 and 15). In the alternative embodiment, after the adhesive tape is bonded to the coil, it draws the insulating tape onto the coil, so that the insulating tape is being wound together with the adhesive tape. After the cutting of the insulating tape (15, 15&#39;), the winding of the insulating tape is completed and fastened by a protruding portion of the adhesive tape which has been cut.

Description:
This application is a divisional of application Ser. No. 175,258, filed Mar. 30, 1988, now U.S. Pat. No. 4,869,763. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a process and apparatus for applying a nonadhesive insulating tape to the winding of an electric coil, which is used, in particular, as an intermediate, cover or shielding insulation. 
     2. Description of the Prior Art 
     Swiss Patent Publication 568,918 discloses an apparatus for applying adhesive tape to the winding of an electric coil wherein a support, capable of being moved between a rest position and a working position, is provided with a pressure shoe for the adhesive tape. On the support, a slide displaceable between two terminal positions is provided. The slide is equipped with means to draw the adhesive tape during its movement into its terminal position in the direction of the pressure shoe. The slide is also equipped with a blade moving on a path transverse to the direction of motion of the slide, between one terminal position of the slide and the pressure shoe. 
     However, this insulating apparatus permits only the use of one-sided adhesive tape, manufactured specifically for this type of application. Only a limited selection of such adhesive tapes is available, so that the different insulation requirements, such as those related to electrical properties, temperature resistance and the like, cannot always be satisfied. 
     In a published German Patent, DE 31 39 496, an apparatus for applying sections of a nonadhesive tape to a winding form is disclosed, which, in the case of a multiple spindle winding machine, is integrated with each winding spindle. As the winding time is usually five times the time required for the application of the tape, the tape winding devices are not optimally used, having a utilization factor of about 20%. Furthermore, during the application of the adhesive tape, the winding machine must be inactive so that additional loss of time cannot be avoided. Another disadvantage consists of the fact that both nonadhesive tapes and tapes coated on one side with an adhesive must be rotated around the longitudinal axes by about 90°, primarily because space is considerably limited due to the given spacing of the spindles. This may lead to problems, especially in the case of broader tapes, since irregularly warped tapes may be produced by stressing. Thus, the uniform application of the tape to the coil is no longer assured. 
     SUMMARY OF THE INVENTION 
     It is the object of the present invention to develop a process and an apparatus for applying insulation to coil windings independently of the process of winding the coils, using nonadhesive insulating tapes. According to the invention, the appropriate plastic, metal and/or paper tapes can be freely selected to insure optimal insulation. By the careful nonrotating introduction of the tapes, they can be uniformly applied to the coil, in accordance with specific requirements. 
     A particular advantage of the invention is that the nonadhesive insulating tapes may be chosen in accordance with prevailing conditions. 
     A further advantage is that a nonadhesive insulating tape with two adhesive ends may be applied stepwise to the coil winding, or a nonadhesive insulating tape may be applied continuously and simultaneously with an adhesive tape. 
     For specific purposes, nonadhesive insulating tapes consisting of different materials may be combined and processed together. For example, plastic/metal tapes drawn from individual supply rolls may be processed together. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other features and objects of the invention will become more apparent from a reading of the Detailed Description in conjunction with the drawings in which: 
     FIG. 1 is a view of an insulating apparatus, 
     FIG. 2A-H and 2a are schematic operating diagrams of the apparatus according to FIG. 1, 
     FIG. 3 is a view of a modified insulating apparatus according to FIG. 1, and 
     FIGS. 4A-F, 4a, 4b are schematic operating diagrams of the apparatus according to FIG. 3. 
    
    
     DETAILED DESCRIPTION 
     In FIG. 1, (1) designates a housing, containing a known drive for a rotating coil holder (7) and a pneumatic control device. 
     A pressure head (2) having a blade (3) for cutting a tape (9) adhesively coated on one side and a blade (4) for cutting a nonadhesive insulating band (15), may be displaced in X and Y axes and actuated pneumatically. Above the coil (8), a vertically guided counter holder (5) is provided. The counter holder is equipped with a slide (6) comprising a recess (6&#39;) for the blade (4). The slide is elastically supported against the coil (8) by the spring (5&#39;). An adhesive tape (9) is drawn from a supply roll (10) to the adhesive tape stress relief installation (11). Tape stress relief installation (11) consists of three reversing rolls (12) and a vertically displaceable stress roll (13), to form a loop of the tape. The tapes (9, 15) are guided over support surfaces of the pressure head (2) and held by means of vacuum suction nozzles (not shown). From a second supply roll (16), a nonadhesive insulating tape (15) is drawn off and guided directly to the support surface of the pressure head (2). A return stop (14) acting against the support surface of the pressure head (2) prevents the withdrawal of the adhesive tape (9), and another return stop roll (17), also acting against the support surface of the pressure head (2), prevents the withdrawal of the nonadhesive insulating tape (15) during the displacement of the pressure head (2) in the horizontal direction of the X axis. 
     The apparatus is operated in individual process steps according to FIGS. 2A-H. 
     Position A 
     As shown in FIG. 2A, the single side adhesive tape (9) drawn from the first supply roll (10), and the nonadhesive tape (15) drawn from the second supply roll (16) are moved into the so-called starting position in the area of an already wound electric coil (8), and held by suction on the pressure head. The adhesive tape (9) is oriented with its adhesive surface facing the coil (8). 
     Position B 
     As shown in FIG. 2B, the pressure head (2) is moved by pneumatic cylinders (2&#39;) against the coil (8), so as to press and bond the adhesive tape (9) partially onto the circumference of the coil winding. Subsequently, the coil (8) rotates against the force of the pneumatically actuated pressure head (2) in a counterclockwise direction by approximately 270°. The pressure head (2) is simultaneously displaced into a laterally offset parting position, and the blade (3) cuts off a piece (9&#39;) of the adhesive tape protruding from the coil (8). 
     Position C 
     The pressure head (2) returns into its starting position (FIG. 2C) and the coil (8) rotates with the freely protruding piece (9&#39;) of the adhesive tape by 180° in the counterclockwise direction, so that the adhesive surface of the piece (9&#39;) of the adhesive tape points toward the nonadhesive insulating tape (15), whereupon the slide (6) is applied against the coil (8). 
     Position D 
     The pressure head (2) is raised in its laterally offset position (FIG. 2D), so that the ends of the tapes (9) and (15) face each other. The pressure head (2) thus pressures the nonadhesive insulating tape (15) against the adhesive surface of the protruding adhesive tape piece (9&#39;). 
     Position E 
     The pressure head (2) moves back into its starting position and the coil (8) rotates in the counterclockwise direction by a predetermined number of turns, thus winding the nonadhesive insulating tape against the spring force of the slide (6) onto the coil (8). Subsequently, the pressure head (2) again moves from its starting position into its laterally offset cutting position (FIG. 2E) and applies pressure to the insulating tape (15) and the slide (6), whereupon the blade (4) cuts the insulating tape (15). 
     Position F 
     The pressure head (2) again moves back into its starting position (FIG. 2F), so that the adhesive tape (9) comes to rest under the already insulated coil (8). The pressure head (2) presses and bonds the adhesive tape (9) partially to the circumference of the insulated coil (8). 
     Position G 
     The tape (8) rotates in the counterclockwise direction (FIG. 2G) against the spring force of the pressure head (2) and the slide (6), to wind the adhesive tape (9) by about 360° and attach the end of the insulating tape (15) to the coil (8). Simultaneously, the blade (3) cuts the adhesive tape (9) at a slight distance from the coil (8), and the overlapping end (9&#39;) of the adhesive tape is wound by further rotation onto the insulated coil (8). 
     According to FIG. 2, therefore, a nonadhesive insulating tape is applied in steps to the coil winding by means of two ends (9&#39;) of the adhesive tape as shown in FIG. 2H. 
     An advantageous variant is obtained according to FIG. 3, with an insulating apparatus whereby both the adhesive tape (9) and the nonadhesive insulating tape (15) are supplied to the apparatus from one side, bonded together and applied simultaneously and continuously to the coil winding. 
     Identical parts are indicated by identical reference symbols in FIG. 1 and 3. 
     In contrast to FIG. 1, in place of the counter holder (5) with the elastically mounted slide (6), a second pressure head (18) with a blade (4) is provided for the nonadhesive insulating tape (15). Pressure head (18) is displaceable and also pivotable, and comprises a sliding surface (18&#39;) in addition to the support surface (18&#34;). The nonadhesive insulating tape (15) is held in a manner similar to the pressure head (2); i.e., by suction on the support surface (18&#34;) of the pressure head (18) (not shown). The adhesive tape feeding device is similar to that of FIG. 1. The nonadhesive insulating tape (15) is drawn off the supply roll (16) and moved to the pressure heads (2, 18) in a manner such that the insulating tape (15) comes to rest at a distance above the adhesive tape (9). 
     It is also possible to use several nonadhesive insulating tapes, by drawing the tapes from several supply rolls. For example, a second tape supply (16&#39;) and pressure head (19), shown in broken lines in FIG. 3, could be added in conjunction with supply (16) and pressure head (18). Two nonadhesive insulating tapes (15, 15&#39;) would be fed to the appropriate pressure heads (18, 19), the pressure heads having associated sliding surfaces (18&#39;, 19&#39;), blades (4, 4&#39;) and return stops (17, 17&#39;). An insulating apparatus so configured makes it possible to use composite insulations, for example plastic/metal tapes. 
     It is also possible, preferably on production lines in which the coils may be freely transported from one station to another, to apply only the insulating tape (15) as an intermediate insulator. The insulating tape (15&#39;) is then applied as the cover insulation to the coil (18) only following the completion of the winding process. Here, the insulating tapes (15, 15&#39;) may consist of different materials, such as plastic, metal or paper. 
     The apparatus according to FIG. 3 is operated in individual process steps according to FIGS. 4A-E. 
     Position A 
     As shown in FIG. 4A, the single side adhesive tape (9) drawn from the first supply roll (10), and the nonadhesive insulating tape (15) drawn from the second supply roll (16), are moved into the starting position in the area of an already wound coil (8) and held by suction on the corresponding support surface of the pressure heads (2, 18). The adhesive tape (9) comes to rest with its adhesive surface facing both the coil (8) and the nonadhesive insulating tape (15). 
     Position B 
     The pressure head (2) moves against the coil (8) (FIG. 4B) so as to press and bond the adhesive tape (9) partially to the circumference of the coil winding of the coil (8). Subsequently, the coil (8) rotates in the counterclockwise direction against the force of the pneumatically actuated pressure head (2). After a rotation of about 270°, the second pressure head (18) pivots with the nonadhesive insulating tape (15) held by suction, against the adhesive surface of the adhesive tape held by suction on the pressure head (2). The adhesive tape (9) is thereby bonded continuously to the nonadhesive insulating tape (15). 
     Position C 
     The coil (8) continues to rotate in the counterclockwise direction (FIG. 4C) as the first pressure head (2) is being moved laterally into the cutting position. Simultaneously, the second pressure head (18) is pivoted into the cutting position, so that the nonadhesive insulating tape (15) runs off over the sliding surface (18&#39;) and the blade (4) cuts the insulating tape after a predetermined length has been fed. 
     Position D 
     The pressure head (18) for the insulating tape (15) pivots back into its starting position (FIG. 4D) and the coil (8) continues to rotate until the nonadhesive insulating tape (15) is wound completely onto the coil (8). At this point an end (9&#39;) protruding over the coil (8) of the adhesive tape is present, which is then cut by the blade (3) and applied to the coil (8) upon the further rotation of the latter, whereby the insulating tape (15) is attached to the coil (8). 
     Therefore, according to the operation of FIGS. 4A-D, a nonadhesive insulating tape is applied continuously to the coil winding by means of two ends (9&#39;) as shown in FIG. 4E. If two or more nonadhesive insulating tapes are used, such as the two tapes (15, 15&#39;) of FIG. 3, an additional pressure head (19) is used, as mentioned above. The two nonadhesive insulating tapes are applied to the coil winding (8) as shown in FIG. 4F. The corresponding process steps are, for the most part, identical with the operating mode described relative to FIGS. 4A-D, whereby, as a rule, the insulating tape (15&#39;) drawn from the supply roll (16&#39;) is initially moved to the pressure head (19), pressed and bonded to the adhesive tape (9), and drawn in by the rotation of the coil (8). Thus, the overlap (a) in FIG. 4F required for the adhesive bonding of the two insulating tapes (15, 15&#39;) to the adhesive tape is relatively small. 
     The processes and the devices of the present invention are not restricted to the winding of electric coils. Other cylindrical bodies with arbitrary cross sections may also be insulated in this manner. The nonadhesive insulating tape or tapes may also be inserted together with the adhesive tape between the individual winding layers of said bodies. 
     Accordingly, although the present invention has been fully described by way of example with reference to the accompanying drawings, it should be noted that various changes and modifications will be apparent to those skilled in the art. Therefore, unless such changes and modifications depart from the scope of the present invention, they should be construed as being included therein.