Apparatus For The Alignment Of Blanks For Motor Plates

Abstract

Apparatus for the alignment of blanks for motor plates, which blanks are cut from material having a trapezoidal cross section. The apparatus includes a ring member and a mandrel located in the opening of the ring member. The mandrel is provided with a plurality of registering elements operative in an alternating manner between an operating position and a rest position whereby each blank received by the apparatus is rotated in its plane with respect to a preceding blank so that the blanks, when superimposed, for a stack having a rectangular cross section.

Parent Case Text

This is a division of application Ser. No. 75,453 filed Sept. 25, 1970 now abandoned.

Description

BACKGROUND OF THE INVENTION

The present invention relates to an apparatus for the alignment of blanks such as semifinished flats or semifinished plates, and more particularly, to blanks which are punched from sheet metal and slotted or grooved, and serve as motor plates for stators or rotors.

In order to obtain as economical a manufacture of such blanks as possible, they are punched from a wide strip of sheet metal in a series in the longitudinal extension of this wide strip in one row or in several rows offset from one another. Due to the deflection or bending of the rolls during the rolling of the wide strip, the cross-section thereof over the entire width of, for example, 1.20 m., is not rectangular but trapezoidal. Accordingly, the punched blanks also have this cross-section, as seen in the cross-section of the wide strip.

If the blanks after slotting were stacked to form sheet metal packs or laminated metal plate packs for motor stators or motor rotors in the position in which they are obtained, one after the other, these stacks would consequently also have an approximately trapezoidal cross-section, which is unfeasible, because the cross-section of the stack must be exactly rectangular. In order to accomplish this objective, each second blank was heretofore turned manually by 180.degree. in the plane of the blank after the slotting step. This procedure is cumbersome because it requires a considerable amount of manual labor in view of the high production efficiency of modern slot punching devices.

SUMMARY OF THE INVENTION

The present invention is aimed at overcoming the problems and disadvantages encountered in the prior art.

The present invention is based on the problem of rendering the alignment of such blanks more economical, so that the blanks can be stacked immediately after the slotting operation in an extremely simple manner into a stack of a rectangular cross-section without any additional working steps, whereby the stack is directly usable as a plate pack for motor stators or motor rotors.

Therefore, the present invention provides an apparatus for the alignment of blanks to be slotted and serving as motor plates from a wide strip having a trapezoidal cross-section. This alignment takes place with respect to the cross-section of the blanks in such a manner that the blanks, when placed one on top of the other, form a stack having a rectangular cross-section.

The above-mentioned problem is solved, according to the present invention, by turning each blank in its plane with respect to the preceding blank prior to the slotting step. The turning step can take place in accordance with the present invention about the same angle and/or in the same sense of direction and/or alternatingly in one sense and then in the opposite sense.

During the punching of the blanks from metal sheets or strips of a rectangular cross-section, the punching operation is also used to serve for producing simultaneously the axial bore or hole and a slot in the rim of the axial bore, or a driving hole or entraining bore, which are employed for orienting the blanks in an accurate position prior to the punching of the slots. For providing such an orientation, a device can be employed consisting of a rotating ring receiving in each case a blank in a centered position and a stationary mandrel or plug disposed in the opening of the ring, which mandrel has a registering element engaging a recess of the blank.

The device is fashioned in such a manner in accordance with the present invention that the mandrel has at least two registering elements alternatingly assuming the operating or working position, which elements are provided at equal spacings from each other and from the longitudinal axis of the mandrel. In accordance with another embodiment of the present invention, the registering elements or devices can be automatically placed into the operating position and into the rest position, for example in an electro-pneumatic fashion.

In close relation with the present invention concerning the process and the devices, the present invention is also based on the problem of fashioning a blank having an axial bore and a slot in the rim of the axial bore for entraining the blank on a centering plate of a slot punching tool in such a manner that the blank can be aligned on the above-mentioned device of the present invention for the alignment of the blank and, furthermore, can be subsequently slotted on a slot punching tool. Therefore, in accordance with the present invention, at least two slots or recesses offset with respect to each other by 180.degree. are provided in the rim of the axial bore in the blank for entrainment on the centering plate, and a third slot is provided in the axial hole for the registering devices, which third slot is wider or deeper than the driving or entrainment slots, or an additional hole or bore is provided in the blank.

In order to solve this problem, a blank having an axial bore and a further hole for entraining the blank on a centering plate of a slote punching tool for the alignment on a device according to the present invention and for the subsequent slotting of the blank, can be fashioned, according to this invention, in such a manner that there are provided, in the blank for being entrained on the centering plate, at least two holes offset by 180.degree. with respect to each other and disposed at equal spacings from the center of the axial bore and a further hole for the registering devices, which latter hole, if arranged at an equal spacing from the center of the axial bore as the driving holes, has a larger diameter than these driving holes, or that a slot is provided in the rim of the axial bore.

The advantages obtained by the present invention reside, in particular, in that blanks having a trapezoidal cross-section can now be punched out from the wide strip, aligned, slotted, and stacked into a satisfactory pack having a rectangular cross section in an extremely simple and economical manner, preferably by machine, i.e., without any manual work, in an uninterrupted sequence of operations, and are thus provided with the layered shape wherein the stacks can be further processed as sheet metal stacks for the stator or rotor of an electric motor.

The supplementation of the conventional apparatus by at least one additional registering device is a measure which is relatively simple from a constructional point of view, thereby making it possible to employ the conventional apparatus readily also for conducting the process of the present invention. Also the shapes of the blanks as provided by the present invention require practically no special measures, since the slots or holes can already be provided in the blank at the time it is punched from the wide strip for, as has been mentioned above, the axial bore and the slot in the rim of the axial bore used to be punched out already during this step in conventional operations.

BRIEF DESCRIPTION OF THE DRAWING

These and further features, objects and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawing which shows, for purposes of illustration only, several embodiments in accordance with the present invention and wherein:

FIG. 1 is a trapezoidal cross-section view of a wide strip;

FIG. 2 is a top view of the wide strip according to FIG. 1 with three rows of blanks to be punched;

FIG. 3 shows a stack of successive blanks of one row, placed one on top of the other;

FIG. 4 shows the various positions assumed by the blanks after punching;

FIG. 5 is a cross-sectional view of an alignment device with two registering elements;

FIG. 6 shows a stack of aligned and slotted blanks in accordance with the present invention;

FIG. 7 shows the mutual positions of the blanks of the stack of FIG. 6 when placed side-by-side; and

FIGS. 8 and 9 are cross-sectional views of centering plates with two driving wedges and two driving pins, respectively.

DETAILED DESCRIPTION OF THE DRAWING

Referring now to the drawing and, in particular, to FIG. 1, the wide strip has an exactly or approximately trapezoidal cross-section due to the deflection caused by the rolling process. It is to be assumed that, from the wide strip shown in FIG. 2, three rows 2, 3, and 4 of blanks, which are offset with respect to one another, are to be punched out on a press in a zig-zag cut. Depending on the degee of deviation of the wide-strip cross section from a rectangle, the blanks of one row likewise exhibit a cross-sectional deviating from a rectangle which, especially in case of the blanks of the external rows 2 and 4, strongly approaches or is equal to the shape of a trapezoid. If the blanks of such a row were stacked one on top of the other in the succession wherein they are punched out of the wide strip, without changing the position thereof in the plane of the blanks, prior to or after the punching of the slots, a stack 5 would be obtained having a cross-section as shown in FIG. 3. The deviations of this cross-section from a rectangle (illustrated in an exaggerated manner for the sake of clarity) differ in dependence on the degree of deviation of the wide strip from this rectangle. However, a stack as shown in FIG. 3 is unusable as a plate or sheet metal pack in a motor stator or rotor since the plate packs must have a very accurate rectangular cross section for this purpose.

In continuous manufacture, all blanks of one series are provided with a specific punched design when punched out from a wide strip. However, in order to explain the present invention, four blanks having different punched designs are illustrated in row 2. The blanks 6 and 7, respectively, are provided, in the rims of their axial bores 8 and 9 respectively, with two slots or recesses 10 and 11, which are offset with respect to each other by 180.degree., so as to be entrained on a centering plate of a slot punching tool. For the registering units, the blanks 6 and 7 either have a third slot 12 which is wider than the slot 10 or a hole 13, respectively.

Blanks 14 and 15, respectively, are provided with axial bores 16 and 17, respectively, as well as two holes 18 and 19 offset with respect to each other by 180.degree. and equally spaced from the center of the axial bore so as to be entrained on a centering plate of a slot punching tool. For the registering units, the blanks 14 and 15 have a further hole 20 or a slot 21 in the rim of the axial bore 17, respectively. In case the hole 20 is equally spaced from the center of the axial bore 16 as the holes 18, the hole 20 is provided with a larger diameter than the holes 18.

Although the blanks are generally stacked in their plane without being rotated after being punched out from the wide strip, the mutual positioning of the blanks in stack 5 is of no significance for the process of the present invention. Consequently, the blanks can also be placed one on top of the other in the stack without any order. The stack 5 assumes the position 23 on the mandrel 22 as shown in FIG. 4 where the blanks are individually withdrawn and are placed, on a rotary table mechanism rotating in the closkwise direction, successively into position 24 for alignment, position 25 for the punching of the slots, and position 26 in order to be transferred for further processing.

In the position 24, the blanks are passed by means of a freely rotatable, pneumatically actuated magnetic head 27, as shown in FIG. 5, into an aligning device consisting in a conventional manner of a rotating ring 28, receiving in each case one blank 6, 7, 14 or 15 in a centered fashion, and further consisting of a stationary mandrel 29 disposed in the ring opening with a registering mechanism 30 engaging a slot of the blank. The device for aligning blanks of a rectangular cross-section is conventional. For purposes of the present invention, the mandrel 29 is equipped with at least one additional registering unit 31. The registering units are disposed in the mandrel 29 at an equal spacing from each other and from the longitudinal axis of the mandrel. They are automatically placed alternatingly into the operating position and, after the aligned blank has been removed from the ring 28, into the rest position, by means of, for example, an electropneumatic apparatus 32, 33. The ring 28 in each case executes a rotation of more than 360.degree. such as, for example, 400.degree. and entrains the magnetic head 27 resting thereon when a blank is being placed thereon. For example, when the registering mechanism 30 has been placed into the operating position, the blank slides over the tip 34 of the pin-like member of the registering unit 30 until the tip 34 engages a recess (slot 12 or 21, or hole 13 or 20 of the blank 6 or 15, or 7 or 14, respectively), so that the blank cannot be entrained any more by the still further rotating ring 28. The cross section of the tips 34, 35 corresponds to that of slots 12, 21 or holes 13, 20. Consequently, the blank is thus aligned in a specific position, independently of the position which it assumed when placed on the ring 28.

When the subsequent blank is placed on the ring 28, which blank has the same punched design as the preceding one, the other registering mechanism 31 is placed into its operating position. The blank slides over the tip 35 of the pin-like member thereof until the slot of the blank passes over this tip 35, which engages the slot and thereby prevents the blank from being further entrained by the ring 28. Since the two registering units 30 and 31 are offset by 180.degree. with respect to each other, the second blank aligned by means of the registering device 31 is turned by 180.degree. with respect to the preceding blank aligned by the registering unit 30. In the case of the subsequent blank placed on the ring 28, the registering unit 30 is again placed into its operating position and so forth, so that each blank is rotated by 180.degree. in the plane of the blank with respect to the preceding blank prior to be slotted. Accordingly, the deviations of the blank cross-sections from the rectangular shape are compensated for between respectively two successive blank. The thus-aligned blanks retain their mutual positioning after leaving position 24 even prior to and after the slotting step in position 25 until arriving at position 26, so that they form, placed one on top of the other, a stack exhibiting a rectangular cross section as seen in FIG. 6. In FIG. 5, the registering mechanism 30 is illustrated in the position wherein its tip 34 has engaged a recess of a blank and prevents the latter from being further entrained by the ring 28 and the magnetic head 27. In this position, the registering device 31 assumes the rest position, wherein its tip 35 is out of contact with the blank. The device according to FIG. 5 can be modified to the effect that the ring 28 is stationary and the mandrel 29 rotates. The movements and registering processes take place in an analogous manner.

In FIG. 7, in order to further clarify the present invention, the mutual positioning of the blanks having the punched design of blanks 6 is illustrated, which these blanks would assume after alignment and slotting, when placed side-by-side prior to stacking. It can be seen from the position of the slot 12 serving for alignment, as well as from the position of the trapezoidal cross-section, that each blank is rotated in its plane by 180.degree. with respect to the preceding blank.

The same effect of obtaining a stack having a rectangular cross-section from blanks having a trapezoidal cross-section, by rotating each blank prior to slotting with respect to the preceding blank in the plane of the blank and by placing the thus-rotated blanks one on top of the other, can also be obtained by providing the mandrel 29 with, for example, three or four registering units instead of two registering units. The units successively assume the operating position and engage the slots 12, 21 or the holes 13, 20. In these cases, each blank is rotated with respect to the preceding blank by 120 or 90.degree.. Correspondingly, the blanks then have, for being engrained on the centering plate of a slot punching tool, this slot must be wider or deeper than the driving slots, or the hole, if the latter is disposed at the same spacing from the center of the axial bore as the driving holes, must have a larger diameter than the driving holes.

FIGS. 8 and 9 show centering plates of a slot punching tool 36 into which the blanks pass when assuming position 25. The centering plate 37 is provided for blanks 6 or 7, and thus is equipped with two wedges or keys 38 offset with respect to each other by 180.degree.. These wedges engage the slots 10 or 11. Correspondingly, for the blanks 14 or 15, the centering plate 39 exhibits two pins 40, offset by 180.degree., engaging the holes 18 or 19. If the blanks in accordance with a rotation by only 120 or 90.degree. in the registering device have three or four slots or holes, the centering plates 37 or 39 are preferably equipped with three or four wedges 38 or pins 40. For entraining the blanks on the centering plates 37 and 39, respectively, one wedge 38 or one pin 40 would be sufficient. However, in order to evenly hold the blanks on the centering plate, it is possible to provide the same number of wedges or pins as there are driving slots or holes.

While I have shown and described several embodiments in accordance with the present invention, it is to be understood that the same is susceptible of numerous changes and modifications as will be apparent to one skilled in the art. I, therefore, do not intend to limit the present invention to the details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scopy of the present invention .

Claims

I claim:

1. Apparatus for receiving a blank in a centered manner, comprising ring means, mandrel means located in an opening of the ring means and having a plurality of registering means operative, in an alternating manner, between an operating position and a rest position and disposed at substantially equal spacings from each other and from the longitudinal axis of the mandrel means, whereby each blank is rotated, prior to slotting, in its plane with respect to a preceding blank so that the blanks, when superimposed, form a stack having a rectangular cross-section.

2. Apparatus according to claim 1, wherein the ring means is stationary and the mandrel means rotates relative thereto.

3. Apparatus according to claim 1, wherein the ring means is rotatable and the mandrel means is stationary relative thereto.

4. Apparatus according to claim 1, wherein the registering means are adapted to be automatically brought into the operating position and the rest position.

5. Apparatus according to claim 4, wherein the ring means is stationary and the mandrel means rotates relative thereto.

6. Apparatus according to claim 4, wherein the ring means is rotatable and the mandrel means is stationary relative thereto.

7. Apparatus according to claim 4, where electro-pneumatic means are provided for automatically bringing the registering means into the operating and rest positions.

8. Apparatus according to claim 1, wherein the registering means in the operating position engages an engagement means of the blank, the blank being provided with an axial bore and at least two opening means, the engagement means of the blank being larger than the opening means.

9. Apparatus according to claim 8, wherein each of the registering means includes a pin-like member arranged for engagement with the engagement means of the blank in the operating position thereof.

10. Apparatus according to claim 9, wherein the engagement means is a slot.

11. Apparatus according to claim 9, wherein the engagement means is a hole.