Centering Device for Blanking Dies

Abstract

A centering device for use with a cutting die in a mold. The die is supported by a sleeve, which rotates about the axis of the die. The device comprises at least two cavities formed on the side surface of the sleeve, which are spaced apart along a same circumference, and at least one wedge-like element that is fastened to the mold and can be alternatively engaged in one of said cavities of the sleeve, with a conical coupling, in order to lock the sleeve after a rotation of the same.

Description

BRIEF DESCRIPTION OF THE DRAWING

Further aspects and the advantages of the present invention will be better understood from the description below, which is to be considered by way of a non-limiting example with reference to the annexed figures, in which:

FIG. 1 is a plane view of a portion of a mold provided with a centering device according to the present invention;

FIG. 2 is a sectional view of a centering device according to the present invention;

FIG. 3 is a plane, top view of the centering device shown in FIG. 2; With reference to FIG. 1 and 2, a mold is shown for progressive cutting of laminates L. A laminate L is fed to the mold in the direction F (FIG. 1).

DETAILED DESCRIPTION OF THE INVENTION

Particularly, the lower portion S of the mold is stationary, and houses at least one cutting die M that is arranged with a vertical axis Y. The upper portion S′ is provided with at least one punch P, also aligned on the axis Y, and is vertically movable in a reciprocating manner, such as to bring the punch P to cut the laminate L at the die M.

After each cutting step, the laminate L is fed for a certain tract in the direction F, which is for a new cutting step. In FIG. 2, the cutting laminations 4 are schematically shown as being temporarily housed in the free space 5 within the die M. The laminations 4 can be stacked for making rotors of electric motors, or for making stators.

The die M is fixed to a sleeve C housed within a suitable seat 7 being formed in the portion S of the mold. The sleeve C is pivotable in the seat 7, supported by bearings B. The rotation of the sleeve C is controlled by a motor (not shown) and allows rotating the die M in order to carry out the compensation of the lamination pack 4.

When the compensation of the lamination pack 4 is required, the sleeve C rotates by a preset angle to bring the die M in the desired angular position, prior to each cutting step.

The mold is provided with a centering device 1 according to the present invention, which has the function of locking the die M in the desired position prior to each cutting step.

With reference to FIG. 2 and 3, the device 1 comprises a wedge-like element 6, which is suitable to engage the sleeve C, in order to temporarily lock the latter during the cutting step. The coupling between the sleeve C and the wedge-like element 6 is of a conical type, without clearance.

The sleeve C is provided with at least two cavities 9 and 9′ that are formed in the sidewall thereof. The cavities 9 and 9′ have the function of housing at least one conical portion of the wedge-like element 6. In the embodiment shown herein, the cavities 9 and 9′ are diametrically opposite relative to the center O of the sleeve C and die M. Generally, the sleeve C can be provided with a plurality of cavities 9, 9′ being arranged along the periphery thereof (on the same circumference) such as to intercept different angles in the center, which correspond to the desired angular positions for the die M.

The wedge-like element 6 of the device 1 is movable in the direction X, i.e. horizontally and transversally to the axis Y, to be fitted within the seat 7 and intercept a cavity 9 or 9′ of the sleeve C. A motor provides to rotate the sleeve C in order to bring a cavity 9 or 9′ into alignment with the conical element, along the direction X. The wedge-like element 6 is slidably fastened to the mold, in a suitable seat of the portion S, and is driven by a cam 2, which is fastened to the upper portion S′.

The cam 2 is movable parallel to the axis Y, with the portion S′ of the mold. The cam 2 is provided with a shaped portion with an inclined surface 22 having the function of being abutted against a matching inclined portion 61 of the wedge-like element 6. When the upper portion S′ of the mold is lowered to the lower portion S to carry out the cutting of the laminate L, the portion 22 of the cam 2 slides on the inclined surface 61 of the wedge-like element 6, thereby causing the movement of the same towards the sleeve C. In other words, the coupling between the cam 2 and the wedge-like element is such that the reciprocating movement of the cam 2 in the vertical direction determines the reciprocating movement of the wedge-like element 6 in the horizontal direction X.

The device 1 further comprises a counter-element 8, such as a spring, having the function of taking the wedge-like element 6 back to its initial position of disengagement relative to the cavity 9 or 9′, when the cam 2 is raised together with the portion S′ of the mold.

As shown in FIG. 2, the cam 2 is provided with a distal end 21 which engages the seat 31 of a bush 3, which is fixed to the portion S of the mold. When the cam 2 is lowered together with the movable portion S′ of the mold, the distal portion 21 of the same is fitted within the bush 3 and is guided in its movement by the latter.

The centering device 1 allows optimizing the performance of the mold, thus favoring a high repeatability of the positionings of the sleeve C, and thus of die M, at each cutting cycle. The conical coupling between the wedge-like element 6 and the sleeve C is free of mechanical clearance, and is also effective when the parts in contact are worn. Any positioning errors due to the inaccuracy of the motor rotating the sleeve C are prevented. The die M is always properly positioned within the mold S, both relative to the punch and relative to the laminate L. Thereby, the die M is worn in a uniform manner.

A further advantage of the device 1 is due to the fact that, as shown in FIG. 1-3, the device is external to the sleeve C, i.e. it is not provided with parts mounted on the rotary sleeve C, which can thus have a minimum size. Thereby, the rotational masses are minimized, with clear dynamic advantages.

Advantageously, the mold provided with the device 1 may not be provided with pilot columns, which engage a bush fastened to the sleeve C, unlike what is provided in the traditional embodiments. In other words, the device 1 allows the mold structure to be simplified.

Claims

1. A centering device (1) for a blanking die (M) within a mold (S), the die being supported by a sleeve (C) to be rotated about the die axis (Y), characterized by at least two cavities (9, 9′) formed on a side surface of said sleeve (C) and spaced along a same circumference, and at least one wedge-like element (6) fastened to said mold (S) and arranged to be alternatively engaged in one of said at least two cavities (9, 9′) of the sleeve (C) with a conical coupling, in order to lock the sleeve (C) following a rotation of the sleeve (C).

2. The device according to claim 2, characterized in that said sleeve (C) comprises a plurality of side cavities (9, 9′) that are angularly spaced apart according to preset angles, in order to allow the sleeve (C) to be locked in a corresponding plurality of angles of rotation.

3. The device according to claim 1 or claim 2, characterized in that said wedge-like element (6) is transversally movable relative to said sleeve (C).

4. The device according to claim 1 or claim 2, characterized in that said wedge-like element (6) is driven by a cam (2) movable with the punch, which in said mold (S) cooperates with said die (M) to carry out the punching operation.

5. The device according to claim 4, characterized in that said cam (2) moves in the vertical direction in an alternate motion, parallel to the axis (Y) of said die (M), and said wedge-like element (6) moves in the horizontal direction (X).

6. The device according to claim 4, characterized in that said cam (2) engages said wedge-like element (6) with a conical coupling.

7. The device according to claim 4, characterized in that said cam (2) is provided with a distal end (21), which engages a bush (3) fixed to a stationary portion of the mold (S).

8. The device according to claim 4, further comprising a counter-element (8) suitable to take said wedge-like element (6) back to its initial position after said cam (2) has been disengaged.

9. The device according to claim 1 in combination with a mold (S) for manufacturing laminations (4) that are cut starting from a laminate.

10. The device according to claim 3, characterized in that said wedge-like element (6) is driven by a cam (2) movable with the punch, which in said mold (S) cooperates with said die (M) to carry out the punching operation.

11. The device according to claim 5, characterized in that said cam (2) engages said wedge-like element (6) with a conical coupling.

12. The device according to claim 5, characterized in that said cam (2) is provided with a distal end (21), which engages a bush (3) fixed to a stationary portion of the mold (S).