A METHOD FOR PROVIDING A PERFECTLY FLAT SURFACE PLATE FOR USE AS A MEASUREMENT REFERENCE PLANE IN STYLING AUTOMOBILES, WHEREIN A MAGNETIC FIXTURE HAVING A FLAT LOWER MAGNETIC FACE IS POSITIONED OVER THE FLOOR ON WHICH IT IS DESIRED TO PROVIDE THE SURFACE PLATE AND A STRIP OF COLD ROLLED STEEL IS POSITIONED AGAINST THE FLAT LOWER MAGNETIC FACE OF THE FIXTURE; THE MAGNETIC FORCE GENERATED BY THE FIXTURE FORCES THE STRIP TO CONFORM TO THE FLATNESS OF THE MAGNETIC FACE AND THE STRIP IS THEREAFTER SET IN PLACE BY FILLING THE SPACE BETWEEN THE STRIP AND THE BASE SURFACE WITH AN EPOXY ADHESIVE WHICH, WHEN HARDENED, SERVES TO MAINTAIN THE STRIP IN THE FLAT CONFIGURATION IMPARTED TO IT BY THE MAGNETIC FIXTURE.
May 1s, 1911 '1H-SMITH 3,579,611
METHOD OF INSTALLING SURFACE PLATE Filed Dec. 2, 1968 United States Patent 3,579,617 METHOD F INSTALLING SURFACE PLATE Robert H. Smith, Birmingham, Robert K. Payne, Troy, and Thomas Haw III, Detroit, Mich., assignors to Chrysler Corporation, Highland Park, Mich.
Filed Dec. 2, 1968, Ser. No. 780,529 Int. Cl. B32b 31/06; E04b 1/16 U.S. Cl. 264-34 6 Claims ABSTRACT 0F THE DISCLOSURE A method of providing a perfectly flat surface plate for use as a measurement reference plane in styling automobiles, wherein a magnetic xture ha-ving a fiat lower magnetic face is positioned over the fioor on which it is desired to provide the surface plate and a strip of cold rolled steel is positioned against the flat lower magnetic face of the fixture; the magnetic force generated by the fixture forces the strip to conform to the fiatness of the magnetic face and the strip is thereafter set in place by filling the space between the strip and the base surface with an epoxy adhesive which, when hardened, serves to maintain the strip in the fiat configuration imparted to it by the magnetic fixture.
BACKGROUND OF INVENTION This invention relates to a method of providing a fiat reference surface. More particularly, it releates to `a method of providing a surface plate for use by automotive stylists and clay modelers for making clay model measurements. It is essential that such a surface plate be absolutely fiat to ensure accuracy and reproducibility of measurements. In the past, these surface plates have been provided as large, bulky iron or steel castings. Installation of these castings in the styling area has involved pre-installation machining operations to impart flatness to the top surface of the casting; leveling, twisting and bending operations to adjust the in situ disposition of the casting; further in situ machining operations to re-establish the flatness of the upper casting surface; and grouting operations to cement the casting in place. Thus, according to the prior art, provision of a surface plate constituted an expensive, awkward and time-consuming project.
SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved method of providing a flat reference surface.
A more specific object is to provide an improved method a of providing a surface plate for use by automotive styling personnel.
Another object is to provide a less expensive method for providing a styling surface plate.
Yet another object is to provide such a method which is less time-consuming than the prior art methods.
Still another object is to provide such a method which, when carefully practiced, will produce a flatter, truer surface plate than that produced by the prior art methods.
Another object is to provide such a method which will facilitate the provision of relatively low, continuous reference surfaces.
Another object is to provide such a method which will make feasible the use of corrosion resistant materials for surface plate installations.
According to the invention, a magnetic :fixture having a fiat lower magnetic face is positioned over a base surface in generally parallel relation to that surface and a strip of flexible, relatively thin magnetizable material is positioned against the fiat lower fixture face to allow the magnetic force generated by the fixture to conform the strip to the fiat fixture face; the space between the strip and the base surface is thereafter filled with a owable, settable material which, when hardened, serves to maintain the strip in the flat configuration imparted to it by the magnetic fixture. The upper face of the strip thus provides a fiat reference surface for use by automotive Stylists or the like.
Other objects and features of the invention will be apparent from the detailed description of the invention to follow.
BRIEF DESCRIPTION OF THE DRAWINGS The method of the invention is illustrated in the accompanying drawings in which FIGS. l and 2 are side elevational views of a magnetic fixture with the fixture shown disposed to practice various steps of the invention;
FIG. 3 is a cross-sectional view taken on line 3-3 of FIG. 2;
FIG. 4 is a cross-sectional view taken on line 4 4 of FIG. 3;
FIG. 5 is a view similar to FIG. 3 showing a further step in the invention method; and
FIGS. 6 and 7 illustrate successive steps in a modification of the invention method.
DETAILED DESCRIPTION The magnetic fixture employed in practicing the method of the invention is best seen in FIGS. '2 and 3. The fixture comprises a beam 10 of I configuration adjustably supported at each end by adjusting screws 12 threadably received in mounting brackets 14 rigidly fastened to each end of the beam. A plurality of magnetic chucks 16 are secured in serial fashion along the underface of beam 10 by bolts 18 countersunk in the lower faces of the chucks and passing upwardly :through the chucks and thereafter through the lower flange 10a of the beam for threaded engagement with nuts 20.
`Chucks 16 -may comprise any known form of generally rectangular magnetic chuck having parallel upper and lower faces. For example, they may comprise 14 inch wide by 48 inch long magnetic chucks available from Hanchett Magna-lok Corp. of Big Rapids, Michigan as Magna-perm series HMP-1448@ Each chuck includes a junction box 22 mounting a power cord 24 for connection to a suitable power source to energize the chuck in known manner and create a magnetic attractive face at the lower face 16a of the chuck.
It is imperative for the successful practice of the invention method that the lower faces 16a of the serially aligned chucks present, in combination, a perfectly flat surface. Since the lower face of beam flange 10a will typically not present a perfectly fiat surface due to dimensional irregularities in the beam, it is necessary to provide a compensating shim between the lower beam face and the chucks. This shim may be formed, as seen in FIG. l, by disposing beam 10 in vertically spaced relation over a known-to-be fiat plate surface 25 and arranging chucks 16 serially on top of beam 10 to allow the beam to deect in accordance with the weight and distribution of the chucks. After leveling the beam by levels (not shown), and after treating surface 25 with a suitable epoxy release material, an epoxy mixture comprising a base and a hardener is poured between the lower face of the beam and surface 25 and allowed to harden to form a shim 26 which adheres to the lower surface of the beam but releases from surface 2S by virtue of the epoxy release material previously applied to that surface. The epoxy mixture may comprise. for example, Bakelite Resin `ERL-2795 and Bakelite Hardener 226-0814, each available from Union Carbide Corp., New York, N.Y.
Referring now again to FIG. 2, chucks 16 are now removed from the top of beam I and fastened by the bolts 18 to the underface of the beam with shim 26 interposed between the beam and the chucks. Since the upper and lower faces of the chuck are parallel, it will be seen that the chucks now present, in combination, a lower magnetic face having a fiatness matching that of the knownto-be fiat surface 25.
A strip 30 of magnetizable material is now placed on a suitable base surface 28, for example a concrete floor, on which it is -desired to establish a fiat reference surface or surface plate, and the fixture is positioned over the plate. Plugs 24 are now connected to a suitable power source to create a magnetic attractive force at the lower faces 16a of the chucks to draw strip 30 to the magnetic face. Strip 30 may be of widely varying composition and configuration. However, it must be sufiiciently thin and iiexible as to allow the magnetic attractive force generated by the magnet to conform the strip to the fiatness of the lower magnetic face. That is, the magnetic force of the magnet must be sufficient to not only attract strip 30 to the magnetic face, but also to hold the strip in a stressed, flattened condition against the magnetic face so that the strip assumes the fiat configuration of the lower magnetic face. Strips formed of one-half inch mill finished cold rolled steel have been found to be satisfactory for a typical styling surface plate installation.
The fixture with strip attached thereto is now leveled, and vertically adjusted as by screws 12 to provide a space of between oneeighth and one-quarter inch between surface 28 and the lower face of strip 30.
A clay dam 32 (FIG. 3) is now constructed completely around strip 30 with a series of sprue holes 34 provided at spaced locations around the darn. Tubes 36 are inserted in sprues 34 and an epoxy adhesive mixture 37 is poured through these tubes to fill the mold space defined between the lower face of strip 30 and surface 28. The expoxy mixture may be the same mixture as used to form shim 26. After the epoxy has cure-d or hardened, the magnetic fixture is de-energized and removed and clay dam 32 is removed. Strip 30 now presents an upper surface 36a having a fiatness conforming to the fiatness of known-to-be fiat surface 25. Another strip 30 may now be laid in end to end aligned relation to the installed strip and the magnetic fixture moved to a location over the new strip to repeat the installation process, with this process being repeated until the desired length of surface plate is achieved.
If desired, and as seen in FIG. 5, the base surface on either side of the installed strip 30 may be raised by the addition of fill concrete 38 to the level of strip 30 so that the upper surface of the strip is essentially fiush with the adjacent base surface.
A modification of the invention method is illustrated in FIGS. 6 and 7. According to the modified method, a channel or trough 40 is provided in base surface 28 so that the base surface comprises a primary portion 28a and a secondary portion 28b defined by the bottom of channel 40. Strip 30 is positioned in channel 40 and the magnetic fixture is positioned over the strip to draw it up to the lower magnetic face of the chucks and fiatten the strip against that face. The fixture is then vertically adjusted to dispose the upper face 30a of the strip generally fiush with primary base surface portion 28a, and tubes 36 are inserted in sprue holes 42 provided at spaced locations around the periphery of trough 40. The epoxy adhesive mixture 37 is then poured through tubes 36 into the mold cavity defined within channel 40 beneath strip 30. After the epoxy cures, the magnetic fixture is removed and sprue holes 42 are filled with a suitable material, eg., concrete. The finished surface plate is seen in FIG. 6.
The invention method will be seen to provide many important advantages over the prior art method utilizing large castings. By the use of the invention method, surface plate may be installed considerably faster and with greater accuracy than previously. The invention method also makes possible the provision of long continuous reference surfaces which, as a practical matter, were unattainable with the prior art casting method. The invention method further allows the use of corrosion resistant materials for surface plates; for example, stainless steel, while difficult and prohibitively expensive to cast in the large sizes required by the prior art casting method, may be readily and inexpensively employed utilizing the invention method.
Although the invention method has been illustrated and described in detail with reference to the accompanying drawing, it will be apparent that various changes and modifications may be made in the details of the disclosed method without departing from the scope or spirit of the invention.
1. A method of providing a fiat reference surface on a base surface, comprising the steps of (A) positioning a magnetic fixture having a fiat lower magnetic face over said base surface with said face paced above and generally parallel to said base surace;
(B) positioning a flexible, relatively thin piece of magnetizable material against said lower face where it may be magnetically held in a fiat stressed configuration against the magnetic face in a position spaced above said base surface;
(c) building a dam on said base surface around the periphery of said piece to define a mold cavity beiween said piece and said surface and within said (D) providing sprue holes in said dam to allow entry of said fiowable settable material into said cavity;
(E) filling the space between said piece and said base surface with a fiowable, settable material which, when hardened, will maintain the piece in the fiat configuration imparted to it by the magnetic fixture to provide a fiat reference surface; and
(F) removing said dam following hardening of said material.
2. A method of providing a fiat reference surface on a base surface, Comprising the steps of (A) providing a channel in said base surface so that said base surface comprises a primary portion and a secondary portion defined by the bottom of said channel;
(B) positioning a magnetic fixture having a fiat lower magnetic face over said base surface with said face paced above and generally parallel to said base surace;
(C) positioning a flexible, relatively thin piece of magnetizable material against said lower face where it may be magnetically held in a fiat, stressed configuration against the magnetic face in a position with the upper surface of said piece generally in horizontal alignment with the primary portion of said base surface; and
(D) pouring a fiowable, settable material into said channel around said piece to fill the space beneath said piece so that, upon hardening of said material, said piece will be lrigidly set in said channel with its fiat upper surface generally fiush with said primary base surface portion and iu the fiat configuration imparted to it by the magnetic fixture to provide a iiat reference surface.
3. The method of claim 2 wherein said magnetic fixture comprises a beam member and at least one magnetic chuck adapted to be secured along the lower face of the beam member, and said method includes the further steps, performed prior to the steps of claim 2, of
(A) positioning said beam member in parallel, vertically spaced relation over a known-to-be fiat surface;
(B) filling the space between the lower surface of said beam and said known-to-be flat surface with a flowable, settable material to form a shim; and (C) securing said at least one magnetic chuck along the lower face of said beam with said shim interposed between said lower face and said chuck to impart a at lower magnetic face as aforesaid to said chuck matching the flatness of said known-to-be at surface. 4. The method of claim 3 including the further step, performed prior tothe filling step of 3-B, of
arranging said at least one magnetic chuck along the top of said beam to allow said beam to deflect in accordance with the Weight of said chuck. 5. The method of claim 1 and including the further step of generally to the level of the upper surface of said strip. 6. The method of 1 wherein said flowable, settable material comprises an epoxy adhesive mixture.
References Cited UNITED STATES PATENTS 3,190,041 6/1965 Kimball 248-19 3,395,209 7/1968 Millard 264-278 ROBERT F. WHITE, Primary Examiner R. SHEAR, Assistant Examiner U.S. Cl. X.R.
raising said base surface on either side of said set strip 15 264-35, 261, 275