US 2366935 A
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Description (OCR text may contain errors)
Jan. 9, 1945.
R. scHMlD VACUUM WORK HOLDER Filed July 24,1945
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tieulany pieces1 tome PatentedjJan. 9,.,1945 r UNITED #STAT Home RenSchnidaLansanne, Switzerland f I. l Arpf geminis. (c1. '5i-:235i A `The.invention@. c)rrsists of aprocessfof attach# wing, objects' to beworled, .more particularly ,those ,whosaweslit is 'smell `in .winparislo.11. .with their en theatre. thin, .there ist a danger f deformgthe ,piece :through such `methods of vattaching them aree@ ian lmown,` and thea iiiekng thegrineine senseless. 1 The-,Only
` iiriculties can, incertain circumstanceaarise Iirifattechnespietato be werked, and moremr- I ,ground `When,"ffor ex I amplefthe weight ef. these pieces Smelliri` Clem- `paris-on fvvithqtheir dimensions, that is to `say method, known.` so far of` maintaining a piece in place without it being under Astrain The device according totheirsternbodiment ofFigs. 1 and 2,` consists ,ofa circular rotary table l, revolving in a bearing: ziqThis table is hollow, itsyupper `face perforated withholes 3 `and its cavity4 communie ate `byanaxial open-` ing with `conduit 5. I
` `The piecetombe gro nd is averythin round washerV s. The drawings show it in Fig. ewan `a piece partlallytorn off `3.of table I.
, in order `to "showholes `This table being iirstlyground, the washer is` placed on it and by conduit 5,l all` or some of the air contained in cavity 4=is drawn off. Fromzthen ofytension, `flexion or pressure, is the magnetic block. This is applicable in certain conditions only, i. e. the piece to be worked must not be paramagnetic and it must offer a suicient pas- I sage to the magnetic flux, which is not the case I for pieces` of small weight in comparison with their dimensions. l i l The difference between the present invention and the procedures hitherto known, is the use of" atmospheric pressure for attaching the piece to be worked to its `support by articiallycreating a vacuum on the surface-of the said piece in contact with the said support. Y
The device used according to `the present` invention for the execution of this procedure con` sists therefore of a support so shaped as to t the piece to be worked and perforated by a certain number of holes, these holes being connectedwith means allowing suction. C
The `annexed drawings yshow three embodiments of the above mentioned device, given by way of example. I
Fig. 1 is a View of the device according tothe first embodiment, showing itin axial cross-section. It serves to attach `very thin disks.
Fig. 2 is a corresponding plane view.
on, ,atmosphericy pressure willIv ensure'the adl Alierence of the washer .to thel tablegwliich, revolving opposite t0 arglndtenenot Hshowlfl here,
allows grinding. of, trailer` `witinput the aachlatter causing it.. the: slightest distortion `in the course of work.
Toremove the washer, it suiices to allow air to enter cavity 4.
.I In the embodiment of a device according to I the present invention shown by Figs. 3 and 4,
the same` principle `as described before is applied I to a cylindrical piece 'I put on a ground muff 8. Thesaidzpiece has thin walls, it is slit its whole possesses moreover an opening length in `9 and The mun s being attached between point II and counterpoint I2 of` a grinding machine, it is set in motion by adriver` I3.
The muff being hollow, cavity I4 communicates with theexterior by a large number of radial holes I5, through its wall.
" cular inside grooved ring I1, of which the `groove Fig. 3Ais a view of a` device, according toV the second embodiment, seen in longitudinal crosssection and usable for attaching cylindrical thin walledobjects, split lengthways and to be ground exteriorly. Such objects would be,` for instance, the operating sleeve of sleeve valve type internal combustion engines. "l
Fig. 4 shows in perspective such a sleeve in place on its cylindrical support. l
Fig. 5 is aview of a device, according to the third embodiment, seen in longitudinal section and applicable to the interiorl grinding of internal combustion engine sleeves. I
coincides with the path followed by theexitoriiices of radial `canals I8. These parts: are not shown in Fig. 4 which has been intentionally simplified.
It is obvious that once cylinder I is put over muli` 8,it will sufce to rarify the air`in cavity i4 by extracting the air throughconduit Iiito` ensure the perfect application of the cylinder to the muiT. A rotary movement of the whole al.
lows exterior grinding of the cylinder. l
As Fig. 4 shows, the perforations of muff 8` must naturally be adapted in shape and size to j the form of the cylinder to be worked, that is:
there 'mustbe no perforations opposite opening I0 asfor instance there were none opposite to central hole of washer 6 in Figs. 1` and 2.
If necessary, it would be possible to conceive supports,` muifs, etc. "with completely perforated surfaces, like a sieve, and which, if desired could I Itis also in communication with a xed conduit I6 by means of a cirbe tapped in order to allow the introduction of small screws with countersunk heads, in view to obturate at will some of said perforations.
The embodiment of the device according to present invention, as shown by Fig. 5, serves for interior grinding of the thin cylinder exteriorly y I -ground by means of the device according to Figs.
3 and 4. The principle is the same. A muff I9, hollow inside to allow for introduction of cylinder 1, has radial openings20 communicating its central opening with a ring-shaped cavity 2l itself communicating, as :has already been explained, with a conduit 22. The muff revolves in bearings 23 and 24, its rotation allows interior grinding of cylinder 1, after being attached by rarifying the air in cavity 2l.
It is obvious that the process of fixing'peculiar .to this invention, as also the device for its execution, can be used for attaching light weight pieces in, comparison with their dimensions, on no matter what machine tool, for example a lathe or a milling machine.
What I claim is:
1.. A device for holding thin split sleeves, whose weight is small in comparison with their dimensions, while being ground to exact size, comprising an elongated, rotatable mui having a continuous cylindrical interior, work-receiving surface accessible through one end of the muff, said Y muff having a hollow space between said interior work-receiving surface and the exterior of the mui and having perforations extending from said work-receiving surface to saidhollow space, and means for applying suction to the hollow space of the mui and to a thin sleeve in place against the work-receiving surface to cause it to be held against such surface, said work-receiving surface having an imperforate area extending in` a straight line opposite which the split in the sleeve may be located, the perforations extending from said interior work-receiving surface to the hollow spaceof the muff being of sufficiently small size and spaced suniciently close to one another, that very thin sleeves placed on the work-receiving surface, over the perforations, will not be deformed by the suction applied to the space within the mui.
2. A device for holding thin split sleeves, whose weight is small in comparison with their dimensions, While being ground to exact size, comprising an elongated, hollow, rotatable muif, said muff having a continuous, cylindrical, work-re.- ceiving `surface having perforations extending therethrough to the space within the muff, an annular member extending around a hollow portion of the mul beyond the work-receiving sur' face thereof, and means connected to said annular member for applying suction thereto, the portion ofthe mui surrounded by said annular member having at least one opening extending therethrough, so that suction applied to the annular member will be' transmitted to the hollow interior of the muff and to a thin sleeve in place against the Work-receiving surface to cause it to be held against such surface, said work-receiving surface having an imperforate area extending in a straight line opposite which'the split in the sleeve may be located, the perforations in said cylindrical Work-receiving surface being of sumciently small size and spaced sufficiently close to one another that very thin sleeves placed on said surface over the perforations'will not be deformed by the suctionapplied to the interior of the muff.