U.S. patent number 3,615,993 [Application Number 04/653,397] was granted by the patent office on 1971-10-26 for magnetic ball production method.
This patent grant is currently assigned to International Business Machines Corporation. Invention is credited to Walter K. French.
United States Patent |
3,615,993 |
French |
October 26, 1971 |
MAGNETIC BALL PRODUCTION METHOD
Abstract
Method of making a sheeting material which is capable of having
graphic subject matter produced thereon and erased therefrom by a
magnetic stylus and wherein one sheet of the material can have
reproduced thereon graphic subject matter present on another
sheet.
Inventors: |
French; Walter K. (Montrose,
NY) |
Assignee: |
International Business Machines
Corporation (Armonk, NY)
|
Family
ID: |
24620701 |
Appl.
No.: |
04/653,397 |
Filed: |
July 14, 1967 |
Current U.S.
Class: |
156/155; 428/900;
335/303; 335/306; 434/409 |
Current CPC
Class: |
B43L
1/008 (20130101); H01F 7/0221 (20130101); H01F
13/003 (20130101); H01F 7/0247 (20130101); Y10S
428/90 (20130101) |
Current International
Class: |
B43L
1/00 (20060101); H01F 13/00 (20060101); H01F
7/02 (20060101); B31 () |
Field of
Search: |
;335/303,306 ;35/66,61
;156/155 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Quarforth; Carl D.
Assistant Examiner: Hunt; Brooks H.
Claims
What is claimed is:
1. A method of making a sheet containing a multiplicity of magnetic
bodies which are capable of being freely rotated under the
influence of a magnetic field applied to the sheet comprising the
steps of:
coating said bodies with a thermoplastic material;
disposing said coated bodies in a planar array;
encapsulating said array with a plastic material to produce said
sheet, said plastic material being chosen to have a melting point
higher than the melting point of said thermoplastic material;
and
heating said sheet to at least render said thermoplastic material
molten, said heating being carried out at a temperature which is
below the melting point of said plastic material whereby said
magnetic bodies are caused to be freely rotatable under the
influence of a magnetic field applied to said sheet.
2. A method of making a sheet containing a multiplicity of
magnetically polarized bodies which are thereby capable of being
freely rotated under the influence of a magnetic field applied to
the sheet, said bodies respectively comprising a first portion of a
first color of one magnetic polarity and a second portion of a
second contrasting color and of opposite magnetic polarity
comprising the steps of:
coating said bodies with a thermoplastic material;
disposing said coated bodies in a planar array;
encapsulating said array within a sheet of plastic material, said
encapsulating material being chosen to have a melting point higher
than the melting point of said thermoplastic material; and
heating said sheet to at least render said thermoplastic material
molten, said heating being carried out at a temperature which is
below the melting point of said encapsulating material whereby said
magnetic bodies are caused to be freely rotatable under the
influence of a magnetic field applied to said sheet.
3. A method of making a sheet containing a multiplicity of
magnetically polarized bodies which are capable of being freely
rotated under the influence of a magnetic field applied to said
sheet, said bodies respectively comprising a first portion of a
first and light color of one magnetic polarity and a second portion
of a second and dark color and of the opposite magnetic polarity
comprising the steps of:
coating said bodies with a thermoplastic material;
disposing said coated bodies in a planar array;
encapsulating said array within a sheet of transparent plastic
material, said plastic material being chosen to have a melting
point higher than the melting point of said thermoplastic material;
and
heating said sheeting to at least render said thermoplastic
material molten, said heating being carried out at a temperature
which is below the melting point of said plastic material whereby
said magnetic bodies are caused to be freely rotatable under the
influence of a magnetic field applied to said sheet.
4. A method of making a sheet containing a multiplicity of
magnetically polarized bodies which are capable of being fully
rotated under the influence of a magnetic stylus applied to said
sheet, said bodies respectively comprising a first portion of a
first and light color of one magnetic polarity and a second portion
of a second and dark color and of the opposite magnetic polarity
comprising the steps of:
slicing a plurality of relatively long cylinders of magnetic
material into respective groups of substantially equal length
relatively short cylinders, said magnetic material which is
utilized comprising semicylinders of light and dark colored
magnetic materials respectively attached to each other along their
diametric surfaces;
maintaining the respective groups of sliced relatively short
cylinders in abutting relationship and coating said groups with a
thermoplastic material;
contracting uniformly under pressure, the diameters of said coated
elongated cylinders to force said thermoplastic material between
said short cylinders to longitudinally space said short cylinders
from each other within said thermoplastic material;
circumferentially notching said coated elongated cylinders at
points between the abutting ends of adjacent short cylinders;
arranging said notched elongated cylinders in substantially
parallel relationship in a planar array;
encapsulating said array in a transparent encapsulating material in
a thin parallelepiped configuration to produce said sheet, said
encapsulating material being chosen to have a melting point higher
than the melting point of said thermoplastic material; and
heating said sheet to expel said thermoplastic material therefrom
to thereby produce a multiplicity of hollow chambers, each of said
chambers containing one of said short cylinders, said heating being
carried out at a temperature which is at least the melting point of
said encapsulating material whereby said thermoplastic material can
be flowed out of said chambers through openings in said
encapsulating material.
5. A method as defined in claim 4 and further including the step of
first producing said relatively long cylinders, said producing
comprising:
welding a sheet of light colored magnetic material to a sheet of
dark colored magnetic material;
cutting said welded sheet into rectangular strips whereby each of
said strips comprises a dark colored material portion and a light
colored material portion;
magnetizing said strips whereby said portions are of opposite
magnetic polarities; and
passing said rectangular strips through a cylindrical extruding die
to convert said strips to cylindrical form to produce said
elongated cylinders.
6. A method as defined in claim 5 wherein said sheets of magnetic
material are selected from the group consisting of a magnetic
rubber and a magnetic plastic.
7. A method of making a sheet containing a multiplicity of spaced,
magnetically polarized bodies which are capable of being fully
rotated under the influence of a magnetic stylus applied to said
sheet, said bodies respectively comprising a first portion of a
first and light color and of one magnetic polarity and a second
portion of a second and dark color and of the opposite magnetic
polarity comprising the steps of:
slicing a plurality of relatively long cylinders of magnetic
material into a plurality of relatively short cylinders, said
cylinders consisting of substantially semicylindrical light and
dark colored portions;
coating said short cylinders at least partly with a thermoplastic
material;
permitting said coated short cylinders to fall through a zone
having a temperature at least sufficiently high to cause said
thermoplastic material to melt and thereby cause said thermoplastic
material to become substantially uniformly distributed around said
cylinders and to cause said coated cylinders to assume a
substantially spherical configuration as they fall through said hot
zone, and to then fall through a zone having a temperature
sufficiently low to cause said thermoplastic material to harden
about said short cylinders;
disposing said coated cylinders in a planar array; and
encapsulating said array in a transparent plastic material in a
thin parallelepiped configuration to produce said sheet, said
encapsulating material being chosen to have a melting point higher
than the melting point of said thermoplastic material whereby, upon
the heating of said sheet to a point at which said thermoplastic
material becomes molten, said cylinders can be freely rotated under
the influence of a magnetic stylus applied to said sheet.
Description
BACKGROUND OF THE INVENTION
This invention relates to materials capable of having graphic
subject matter produced thereon by magnetic means. More
particularly, it relates to a novel sheet and a method of making
thereof, which can be used both for having graphic subject matter
inscribed thereon by a magnetic instrument and for reproducing such
graphic subject matter on one sheet on another sheet.
Magnetic slates and chalkless blackboards are well known. Examples
of such devices are those wherein a magnetic stylus coalesces
magnetic particles to produce graphic subject matter, those wherein
a magnetic stylus pulls into view magnetic particles which are
contained in respective chambers, and those wherein a magnetic
stylus rotates individual magnetic material spheres having
contrastingly colored hemispheres contained within individual
pockets.
It is an object of this invention to provide a method of making a
thin sheet material capable of having graphic subject matter
inscribed thereon and erased therefrom by magnetic means.
It is another object to provide a method of making a thin sheet
material capable of having graphic subject matter inscribed thereon
and erased therefrom by magnetic means and of having inscribed
graphic subject matter thereon reproducible therefrom.
It is a further object to provide the thin sheet material produced
in accordance with the method of the preceding objects.
It is a still further object to provide a method for reproducing
graphic subject matter utilizing sheets of the material provided in
accordance with the preceding objects.
SUMMARY OF THE INVENTION
In accordance with the invention there is provided a method of
making a sheet containing a multiplicity of magnetic bodies which
are capable of being freely rotated under the influence of a
magnetic field applied to the sheet. The method comprises coating
the bodies with a thermoplastic material, arranging the coated
bodies in a planar array and enveloping the array in a sheeting
material to produce the sheet.
Also in accordance with the invention there is provided a sheet
capable of being written on by a magnetic stylus comprising a thin
planar structure which comprises a transparent plastic material and
a multiplicity of adjacently disposed chambers contained within the
structure. Each of the chambers contains a magnetically polarized
magnetic material body which is free to rotate within its chamber,
each of the magnetic bodies comprising a first portion of one
magnetic polarity and of a relatively light color and a second
portion of the opposite polarity and of a relatively dark
color.
This is further provided a method of reproducing graphic subject
matter which comprises a first step of producing graphic subject
matter by writing with a magnetic stylus on a first heated sheet,
the latter first heated sheet comprising a thin planar structure
which comprises a transparent plastic material containing a
multiplicity of adjacently disposed chambers. Each of the chambers
contains a thermoplastic material and a magnetically polarized
magnetic material body which is free to rotate within its chamber
when the thermoplastic material is softened by heating. Each of the
magnetic bodies comprises a first portion of one magnetic polarity
and of a relatively light color and a second portion of the
opposite magnetic polarity and of a relatively dark color. The
method further comprises a second step of cooling the first sheet
after the graphic subject matter has been written thereon to harden
the heat softened thermoplastic material and thereby fix the
disposition of the magnetic material bodies within their respective
chambers. The method also comprises a third step of placing a
second sheet having the same structure as the first sheet and
sufficiently heated to soften the thermoplastic material contained
therein in intimate contact with the first sheet whereby the
magnetic material bodies contained in the second sheet are caused
to be rotated to magnetically conform to the disposition of the
magnetic material bodies contained in the first sheet whereby the
graphic subject matter on the first sheet is reproduced on the
second sheet.
The foregoing and other objects, features and advantages of the
invention will be apparent from the following more particular
description of preferred embodiments of the invention, as
illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a depiction of the stage in accordance with the method of
the invention wherein an elongated cylinder of magnetic material is
produced;
FIG. 2A shows the stage of the method according to the invention
wherein the elongated cylinder is sliced up into short
cylinders;
FIG. 2B shows a suitable support arrangement suitable for use in
the stage depicted in FIG. 2A;
FIG. 3 depicts the step wherein the cut elongated cylinder is
coated with a "release agent" such as a thermoplastic material;
FIG. 4 shows the step in which the coated elongated cylinder is
contracted in diameter to cause the thermoplastic material to space
the short cylinders from each other;
FIG. 5 depicts in cross section the step in which the contracted
diameter coated cylinder is circumferentially notched at points
between adjacent short cylinders;
FIG. 6 is a view, partly in section, which shows the step according
to the method of the invention wherein the notched coated cylinders
are encapsulated to form a sheet;
FIG. 7 is a view, partly in section, of the sheet resulting from
the step depicted in FIG. 6;
FIG. 8 is a view, partly in section, which shows the sheet of FIG.
7 with the release agent removed therefrom;
FIG. 9 is an elevational view, partly in section, of apparatus for
providing another embodiment of release agent coated magnetic
material bodies, in accordance with the invention;
FIG. 10 is a cross-sectional view illustrating the encapsulating
into a sheet of the bodies produced in the apparatus shown in FIG.
9;
FIG. 11 is a view, partly in section, of a sheet formed, according
to the invention, of the magnetic bodies produced in the apparatus
of FIG. 9; and
FIG. 12 is a three-dimensional view of a graphic subject matter
copier utilizing the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
Reference is now made to FIGS. 1-8 wherein there are respectively
depicted various stages in the method according to the
invention.
In FIG. 1 there is shown a rectangular rodlike structure 20 which
suitably consists of a magnetic rubber or a magnetic plastic
material. If desired structure 20 may consist of two magnetic
material laminates 22 and 24 suitably welded or otherwise attached
together, each of the laminates being of different colors. Thus,
one magnetic laminate 22 may be white and the other magnetic
laminate 24 may be black.
A magnet 26 which may be of the fixed or electromagnetic type may
be provided to magnetize structure 20. As shown for convenience of
explanation, the upper portion or laminate 22 of structure 20 is
given a north pole magnetic orientation and the lower portion or
laminate 26 is given a south pole magnetic orientation in
accordance with the magnetic poling shown for magnet 26. It is
readily appreciated that structure 20 may be provided in very thin
slices from a sheet or laminated sheet of magnetic rubber or
magnetic plastic.
After structure 20 has been polarizedly magnetized, it may be
passed through an extrusion die 28 or other suitable device to
produce a rod of substantially right circular cylindrical
configuration. Alternatively, structure 20 may be sliced into cubes
or parallelepipeds.
FIG. 2A schematically depicts the cutting step in the processing of
rod 30. Since there are being handled structures of extremely small
dimensions (for example, rod 30 may have a diameter in the order of
about 3- 100 microns, and cut lengths of rod 30 of about the same
order, it is necessary to provide a very thin cutting mechanism). A
suitable mechanism for effecting such cutting may be an extremely
thin blade, an ultrasonic wave source, or a mechanism such as a
laser 32 as shown in FIG. 2A. Thus, as rod 30 is passed by a
cutting station, cutting mechanism 32 is operative to cut rod 30
into equal length cylindrical sections 34.
FIG. 2B shows an example of an arrangement for maintaining cut
sections 34 in alignment and in abutting relationship and suitably
comprises a trough 33 and a tensioning spring 35.
FIG. 3 schematically depicts the step of coating of cut rod 30 with
a "release agent," the latter term being intended to signify a
paraffin, wax or other quan-lubricant or thermoplastic material
which softens or flows at relatively slightly elevated temperatures
and which in its softened or fluid state will insinuate itself
between adjacent abutting cylinders 34. A suitable example of a
liquid release agent is glycerine. Wax is a suitable example of a
thermoplastic release agent. In this connection, it is to be noted
that in FIGS. 2A, 2B and 3, cylinders 34 are shown as remaining in
abutting contact and in alignment to together retain the
configuration of rod 30. Cylinders 34, as has been explained
hereinabove, may be extremely small. However, to insure that they
may remain in contact when desired, well-known mechanical
expedients can be employed such as spring loaded plungers, a trough
along which they are moved and the like, as hereinabove described
in connection with FIG. 2A.
In the release agent coating step shown in FIG. 3, cut rod 30 is
passed through a vessel 36 containing the release agent 38 therein
to have the release agent applied thereto whereby there is produced
a rod 40 having as its inner core rod 30 comprising cut cylinders
34 and an outer coating 38 of release agent. Vessel 36 may be a
vibratory coater or like suitable coating device.
In FIG. 4, there is schematically depicted the releasing step. In
this step, rod 40 is passed through a die 42 whose diameter tapers
from right to left whereby the diameter of rod 40 is contracted and
the release agent 38 is forced between adjacent cylinders 34. The
resulting rod 46 emerging from die 42 contains aligned cylinders 34
substantially equispaced from each other by release agent.
In FIG. 5, there is schematically depicted a crimping step. In this
step, rod 46 is passed by a crimping tool 48 which provides spaced
circumferential notches 50 around rod 46 intermediate respective
adjacent cylinders 34.
In FIG. 6, there is shown the encapsulating or casting step. In
this step, a plurality of equal length crimped rods are placed side
by side to form a rectangular suitably spaced array thereof and are
then potted or cast in a suitable transparent plastic 53 or other
encapsulating material in a shaped container 52 whereby there is
produced in container 52 as shown in FIG. 7, a clear plastic sheet
54 containing a plurality of equispaced substantially parallel
disposed rods 46.
In FIG. 8, there is shown the construction of sheet 54 after
release agent 38 has been removed therefrom. Such removal is
suitably effected by heating sheet 54 whereby release agent 38
becomes molten and readily flows out. Such flowing out can readily
be effected through the ends of columns 46 as shown in FIG. 8. It
is, of course, to be realized that plastic 53 and release agent 38
have to be so chosen whereby plastic 53 has a melting point
sufficiently higher than release agent 38 to insure that sheet 54
does not buckle when it is heated to remove release agent 38
therefrom.
At this point, finished sheet 54' as shown in FIG. 8 can again be
subjected to a strong polarizing magnetic field across its
surfaces. There, thereby results from the process, according to the
invention, a sheet comprising a plurality of individually freely
turnable compartmentalized magnetic cylinders 34. With cylinders 34
having a diameter in the few to 100 micron range, sheet 54 need
only have the thickness of paper. Sheet 54 or 54' can be written
upon and erased with a bar magnet and may be written on
automatically with a moving electromagnet which is moving in
synchronization with a communication channel or tape recorder.
In a variation of the embodiment shown in FIGS. 1 to 8, the release
agent need not be removed from sheet 54 but may be one which
softens at a relatively slightly elevated temperature. For example,
it may be a wax which softens sufficiently at a temperature of
150.degree. F.-180.degree. F. In this case, the heating of sheet 54
to the latter temperature would be required to permit magnetic
writing thereon. With this variation, there can be effected a
simple copying device as is further explained hereinbelow. Thus, if
it is assumed that one sheet has been written on and has black
graphic subject matter thereon, i.e., one portion of all of the
magnetic material bodies are black, such written on sheet is
permitted to cool until the release agent therein has hardened. A
second sheet 54 is heated until the release agent softens to permit
the magnetic cylinders 34 therein to rotate freely. The two sheets
are then placed in intimate contact whereupon the heated sheet will
take on the image of the graphic subject matter on the other sheet
and retain it up on its cooling. Thus, with a simple hot plate or
like device, a copier may be provided.
Referring now to FIG. 9, there is depicted therein an apparatus
suitable for use in producing another embodiment of the
invention.
In FIG. 9, cylindrical or parallelepiped magnetic material bodies
34 such as are produced by the slicing of cylinder 30 or rod 20
(FIG. 1) are fed into an inclined hopper whereby they slide down
the inner surface 61 of hopper 60 into a tower 64. The structure 62
represents a source of a release agent 63 such as a wax or
glycerine which is poured along surface 60 whereby magnetic
material bodies 34 are coated, at least in part, by the release
agent as they slide down surface 61.
Tower 64 may be of the type in which shot is manufactured and
comprises a hot zone 65 and a cold zone 67. Hot zone 65 may
suitably be heated by a coil 66, a hot air source or other
well-known means used for such purpose. Cold zone 67 may be cooled
by cooling coils 68, a fan or other suitable device. As the coated
magnetic material bodies 34 fall through hot zone 65 of tower 64,
their outer surfaces, i.e., of the release agent, melt, whereby the
bodies fall assume a substantially spherical configuration and such
configuration is hardened into place as the coated bodies fall
through cold zone 67. The hardened little spheres terminate their
movements in an arresting device 70, shown in FIG. 9 as a liquid
containing tank. However, device 70 may be a ramp or other suitable
stop. It is to be realized that magnetic material bodies 34
themselves could be rendered substantially spherical by their
dropping through tower 64.
The spheres produced in the apparatus shown in FIG. 9 are laid out
in a rectangular array and in tangential contact with each other
and are then encapsulated, the encapsulating step being shown in
FIG. 10, FIG. 10 illustrating substantially the same step as that
shown in FIG. 6.
FIG. 11 is a view similar to that of FIG. 7 and shows the finished
sheet with the magnetic material bodies embedded in their release
agent. The chambers are substantially spherical.
FIG. 12 shows an office copier device which can be made utilizing
the sheet made in accordance with the invention. In the device of
FIG. 12, the structure 72 illustrates a hot plate for heating a
sheet. Sheet 74 has had graphic subject matter entered thereinto by
the writing thereon with a magnetic stylus. Such writing was
effected by using a sheet 74 (such as sheet 54) in which the
release agent of the thermoplastic type had not been removed
therefrom but wherein the sheet had been heated so as to enable the
magnetic material bodies in the sheet to be rotated freely within
their embedding release agent. After the sheet 74 had been written
upon, it had been permitted to cool to freeze the magnetic material
bodies into place within their hardened release agent. Now, in the
copying step, a blank sheet 76, identical in construction to that
of sheet 74 is heated on hot plate 72 to free its magnetic material
bodies within their embedding release agent and cool sheet 74 is
placed thereon. In this situation, since only the magnetic material
bodies of sheet 76 are free to move, the latter align themselves in
accordance with the pattern of the magnetic material bodies in
sheet 74 and the graphic subject matter on sheet 74 is reproduced
on sheet 76.
While the invention has been particularly shown and described with
reference to preferred embodiments thereof, it will be understood
by those skilled in the art that the foregoing and other changes in
form and details may be made therein without departing from the
spirit and scope of the invention.
* * * * *