MACHINE FOR DRIVING AND VARIABLE LENGTH CUTTING OF THE ARMATURE PAPER OF THE ELECTRIC MOTORS ROTOR

Abstract: A machine for driving and variable length cutting of the paper (10) which forms the armature of the electric motor rotors comprises a feed distance covered by the paper between shaping rollers (11); or these a pressure wheel (15) is located which pushes the paper against a ledge (19) and then slips on the said paper; a paper cutting blade (20) is inserted between the wheel and the ledge; transfer devices are located between the blade and the ledge for the transfer of the cut paper to a bending fixture (22) which gives it the shape of the rotor slot and into which it is being pushed by the inserting devices (31); the rotor (23) is being translated from the conveyor (34) on which it is fed by locking elements (25,26) in the suitable position to receive the paper; such locking elements are directly connected with the position of the ledge to vary the length of the cut paper with respect to the height of the rotor slots where it is being inserted.

Description: Subject of the invention is a machine for driving and variable length cutting of the paper which has to be inserted in slots of electric motor components, in particular armatures. One of the purposes of the invention is to propose a machine able to obtain a minimum length difference among the various insulating elements required for electric motor component of a given size. Purpose of the invention is also to propose a machine able to automatically vary the length of the insulating paper according to the electric motor component which must be processed. US 4136433 and FR 1574500 disclose machines for the production and insertion of insulating elements for electric motor components comprising means for feeding the paper from a supply roll and means for shaping the paper in order to fit it in a slot of the motor component; these machines further comprise means for obtaining that a predetermined length of the paper can be cut, and means for inserting the shaped and cut insulating element into the motor component slot. However, US 4136433 proposes manual adjustment for variating the paper feed in order to obtain insulating elements of desired length and FR 1574500 proposes a variable ledge and a cutting blade which are positioned at different predetermined distances with respect to one another in order to obtain insulating elements of different sizes for variations in the width of stator slots. The above prior art, therefore, do not obtain the objects of the present invention that have been stated in the foregoing. For the above scopes the invention propose, therefore, a machine for driving and variable length cutting of the paper which has to be inserted in slots of electric motor components as claimed in claim 1. A description of the machine according to the invention follows and reference is made to the enclosed drawings: Fig. 1 is a longitudinal sectional view of an illustrative embodiment of the machine of this invention. Fig. 1a is a partialtop view of the machine of Fig. 1. Figs. 2a, 2b and 2c are enlarged views of a portion of the machine illustrated in Fig. 1 showing three different operating positions. Fig. 3 is a perspective view of a portion of the machine. Figs. 4 and 5 are enlarged view of a portion of the machine shown in two different operating positions. The paper belt 10 is continuously fed between two rollers 11 (see Fig. 1) from an external paper supply coil or roll (not illustrated). Rollers 11 shape and engrave the paper in a predetermined pattern so that when the paper is subsequently inserted in the slots of the rotor, it conforms to the shape of the slot in the best possible way. The paper belt or web 10, formed by the rollers 11, performs a free downward descent, forming a loop which is limited in size by two photocells 12 and 13, which give the maximum loop length and the minimum loop length, respectively. When paper 10 reaches the loop top, two paper guides 14, exact with respect to the paper's width, guide the paper while a wheel 15, covered with wear-resisting material and rotated by a geared motor 16, pushes the paper onwards, by means of frictional engagement of the paper. A cylinder 17, the pressure of which is adjusted by a gauge, operates the lever 18 on which geared motor 16 is assembled. Geared motor 16 drives paper drive wheel 15. The friction between wheel 15 and paper 10 makes the paper move between guides 14 until it rests against ledge 19. A kinematic assembly commands cutting blade 20, to cut the paper. Plate 21 pushes the cut paper downward and inserts it in a portion 22 of the fixture having the shape of the armature stack slot, this bends the paper along a longitudinal median in order to give it the definite shape 30 (fig. 3). At this point, an inserting device 31 pushes the shaped paper into the slots 32 of the armature stack 23. When the cutting blade goes up again, wheel 15 (which was slipping on the remaining paper against cutting blade 20), feeds the paper at the maximum speed, making it hit against ledge 19. The paper, having reached the desired length without mistakes, waits to be cut again and rubber wheel 15 begins to slip again. When the insulation of rotor 23 is complete, ledge 19, which is moved by cylinder 24 (fig. 1a), moves backward and jaw 27 places armature 23 back on coveyor 34 (fig. 4). Conveyor 34 performs a step, presents a new armature 23, and lifts it in the paper insertion area. The cylinder 24, with thrust blocks 25 and 26, are moved to bear on the new rotor 23. Thrust blocks 25 and 26 are connected by a predetermined dimension to paper ledge 19, so that according to the height of the armature, thrust blocks 25 and 26, and ledge 19, will conform themselves to such height, thus determining the length of the cut paper, which must be equal to the height of the armature stack. This also recovers the height tolerance of the armature stack. With regard to the paper driving system, a cylinder 17, the pressure of which can be adjusted, operates lever 18 which carries geared motor 16. The geared motor drives paper drive wheel 15. Paper 10, having been inserted in guides 14, is pushed against ledge 19 by wheel 15; as soon as it reaches ledge 19, wheel 15 slips on paper 10. The machine carries out the shaping, cutting, and insertion functions as described above. When the operators of the machine are reset, the paper is released, and it accomplishes another step forward. Regarding the automatic detection of the length of the paper, which must be equal to the height of the armature stack, jaw 27 lifts rotor 23 off the conveyor, and cylinder 24, by means of thrust blocks 25, pushes the armature stack 23 until it bears against thrust blocks 26, which are on the side of the paper shaping fixture 22. The ledge 19, where the paper 10 bears and is fed by wheel 15, is assembled integral to cylinder 24. The length of the paper for each rotor 23 equal to the height of the armature stack is thus determined; the differences which could have existed between the paper and the armature stack, caused by the armature's wide tolerance, are thus recovered.

Claims: Machine for driving and variable length cutting of paper which is to be inserted in slots of electric motor components, in particular armatures, comprising means for feeding the paper from a supply roll to shaping rollers (11) and subsequently against a variable position ledge (19); between the shaping rollers (11) and tile ledge (19) there being inserted a paper cutting blade (20) and between the blade (20) and the ledge (19) there being located transfer devices (21) for the transfer of the cut paper to a bending fixture (22) which bends the paper to the shape of the slot (23) into which it is pushed by inserting devices (30, 31); means for positioning the motor component in the required position to receive the paper, characterized in that the machine further comprises devices for detecting the stack slot height directly connected to the variable position of the ledge (19) in order to equalize the length of the cut paper with the height of the slots in which it is inserted. Machine according to claim 1 characterized in that between the feeding means and the variable ledge (19) the paper (10) performs a free loop having minimum and maximum lenght controlled by respective photocells (12 and 13). Machine according to claims 1 and 2 characterized in that a pressure wheel (15) is located after the sheping rollers (11) for feeding the paper from the free loop and for pushing the paper from the free loop and for pushing it against the variable ledge (19). Machine according to claim 3 characterized in that the pressure wheel (15) is kept pressed on the paper by means of a lever (18) operated by a cylinder (17) in order to push the paper against the ledge (19) and then to slip on it during each cutting cycle. Machine according to claim 1 characterized in that the elements (25, 26) for detecting the slot height are thrust blocks which bear against the end of the stack slots, and where at least one thrust block (25) is movable and connected to a cylinder (24) which positions the ledge (19) with respect to the blade (20) at a distance from it which is substantially equal to the distance between the thrust blocks (25, 26) after they have come to bear against the stack slots. Machine according to claim 1 characterized in that the means for positioning the motor component are a conveyor (34), for feeding the component, and locking elements (24, 25) for translating the motor component from the conveyor (34) in the required position for receiving the paper. Machine according to claims 5 and 6 characterized in the devices for detecting the stack slot height are the same elements (25, 26) for locking the stack in the position suitable to receive the paper.

Inventors: LOMBARDI, MASSIMO, SANTANDREA, LUCIANO
Applicants: AXIS S.P.A.
Application year: 1988
Main classification: H02K15
IPC codes: B26D7, B26D1, H02K15