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BACKGROUND OF THE INVENTION
The present invention relates a method and apparatus for removing warps or
surface irregularities from phonograph records, and more particularly,
records made of polyvinyl materials such as used in modern, long-playing,
high fidelity records. Such records are often delivered by a supplier to
the end user in a moderately to severely warped condition. Such conditions
generally result from a combination of factors, including inadequately
controlled manufacturing processes, temperature variations and stresses
during shipping and storage, and inadequate storage facilities or
conditions maintained by the supplier. Once in the hands of the end user
or consumer, such planar records are subject to further warpage and
deterioration with usage and due to further inadequate storage facilities
and conditions.
Warpage of modern polyvinyl records presents problems which did not exist
with the older type, less pliable 78 RPM records. Because modern,
sophisticated, high fidelity sound reproduction equipment is capable of
following and reproducing all variations on a record, including warps,
even very small non-planar variations in the surface of a record adversely
affect the fidelity of the reproduced sound. In addition to the loss of
fidelity in the sound reproduction, subsonic signals can be generated by
even a slightly warped record which can drive a hi-fi power amplifier into
a clipping region further distorting fidelity and potentially causing
damage to loud-speakers. Extreme warps can render a record unplayable.
Even with turntable, tonearm and cartridge combinations of extreme
sophistication, unacceptable quality sound reproduction occurs with record
warpage.
Subsonic signals are also reported to be capable of causing adverse
physiological effects known generically as flicker vertigo, which can
produce spatial disorientation or blackout if the signals are of
sufficient strength and duration. Reportedly, even minute warps in a
record can generate such subsonic signals through an appropriate amplifing
system.
Although U.S. Pat. No. 2,388,127 discloses an apparatus for flattening disc
records, it is totally inapplicable to modern records since, for example,
it utilizes two superposed plates which engage the playing surface of the
record. Although this technique would be appropriate for an earlier
generation record it would severely damage a modern polyvinyl record.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a method
and apparatus for removing warps or surface irregularities in polyvinyl
records.
It is a further object of the present invention to provide apparatus which
is inexpensive and simple to use.
Toward the fulfillment of these and other objects of the present invention,
a plurality of plate-like members are provided which are adapted to engage
with the lead-in lips on one or more records and to clamp one or more
records therebetween for the application of appropriate forces to the
records. The plate-like members are provided with centering apertures to
facilitate record registration between the plates, and releasable and
adjustable clamping means are provided. The plate-like members are further
provided with means to engage with the label portions of the record
clamped therebetween but not to engage with the playing surfaces of the
records. By appropriate tightening and adjustment of the clamping means,
record warpage and surface irregularities may be removed. In one
embodiment of the invention, the plate-like members are bowed to permit
the application of lateral as well as vertical forces to a record. The
application of moderate heat from an external source facilitates warpage
removal.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of a plate-like member used in the present invention.
FIG. 2A is a partial cross-sectional view along line II--II of FIG. 1;
FIG. 2B is a view similar to FIG. 2A but illustrates another plate-like
member used in one embodiment of the invention;
FIG. 2C is a view similar to FIG. 2A but illustrates a further plate-like
member used in one embodiment of the invention.
FIG. 3 is a cross-sectional view showing a first embodiment of apparatus of
the invention as used in operation.
FIG. 4 is a cross-sectional view similar to that in FIG. 3 but showing a
second embodiment of apparatus of the invention.
FIG. 5 is a further cross-sectional view similar to that in FIG. 3 but
showing a third embodiment of apparatus of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1 of the drawings, the reference numeral 10 refers in
general to a plate-like member utilized in the apparatus according to the
present invention. The member 10 is generally circular in shape and has a
plurality of apertures 12a, 12b, 12c, and 12d disposed about its outer
periphery in an equalangularly spaced relationship and extending through
the member for receiving shafts or bolts as will be explained in detail
later. The member 10 also includes a central aperture 12e which is also
adapted to receive a shaft or a bolt. As shown in FIG. 2A the underside of
the member 10 includes an elevated lip area 14 and an elevated area 16,
both elevated with respect to the generally planar undersurface of the
member 10. The plate-like member 10 has an upper exterior surface 17 and a
lower exterior surface 18 which includes circular elevated regions 16 and
14 disposed concentrically about the central aperture 12e. In a preferred
embodiment, the diameter of the elevated region 16 corresponds
approximately to the central label region on a polyvinyl record, and is
typically in the range of 4.00" to 4.25". The non-elevated portion of the
lower surface 18 is selected to correspond to the playing surface of a
polyvinyl record 11 positioned parallel to the member 10 and with its
center hole aligned with the hole 12e. With this arrangement there can be
no engagement or contact between the surface 18 and the playing surface of
a record with the member 10 positioned over the record. The outer elevated
region 14 of the lower surface preferably has a width in the range of
0.125" to 0.200", and is selected to engage with the outer edge or lead-in
lip of the record. The portion 19 of the member 10 designates the outer
periphery portion of the member which contain the apertures or holes, 12a,
12c, etc. as also shown in FIG. 1.
FIG. 2B illustrates a similar view of another plate-like member 20 used in
one embodiment of the present invention. The member 20 also includes the
central aperture 12e, and the peripheral apertures 12a, and 12c and other
peripheral apertures (not shown in the view in FIG. 2B). The plate-like
member 20 includes a region 24 which corresponds to the playing surface of
a record (e.g. 21,29) positioned parallel to the member 20 and with its
central hole aligned with the central hole 12e. Two elevated regions 22
and 25 are provided on the upper surface of the member 20, and two
corresponding elevated regions 23 and 26 are provided on the lower surface
of the member 20. The elevated regions 22 and 23 correspond dimensionally
and functionally to the elevated region 14 of FIG. 2A, and the elevated
regions 25 and 26 correspond dimensionally and functionally to the
elevated region 16 of FIG. 2A. Similarly, portion 27 of the member 20
corresponds to the element 19 of FIG. 2A.
FIG. 2C illustrates another plate-like member 30 used in another embodiment
of the invention and which corresponds generally to the member 10 of FIG.
2A. The elements 31, 34, 36, 37, 38 shown in FIG. 2C correspond to the
elements designated by the comparable numerals 11, 14, 16, 17, 18 in FIG.
2A. The difference between the member 30 and the member 10 is that the
member 30 is bowed so that the elevated surface 36 is vertically displaced
relative to the elevated surface 34 by approximately 1/32" to 1/8" when
the member 30 is not subjected to externally applied stresses or forces.
FIG. 3 is a cross-sectional view of a first embodiment of apparatus
according to the present invention illustrating the method of the
invention. The apparatus of FIG. 3 is adapted to hold two records 45 and
46 having warps or surface irregularities desired to be removed. Upper and
lower exterior, plate-like members 10 are provided. Two interior
plate-like members 41 and 42 are also provided, each corresponding
substantially to the plate-like member 10 except that the thickness of the
internal members 41 and 42 need not be as great as the thickness of the
exterior members 10, and for example, need only be 50% as thick as the
exterior member 10. The bottom, exterior plate-like member 10 is the same
as the upper, exterior plate-like member 10 previously described and the
diameters of both members are slightly greater than that of the records
45, 46 so that the peripheral apertures 12a, 12b, 12c, and 12d clear the
outer edges of the records.
In operation, a bolt or spindle 47c is inserted through the central
aperture of the bottom member 10. Next, a record 45 having warps is
inserted in position with the bolt 47c extending through its center hole
so that the record rests on the record engaging surfaces of the member 10.
Then, the internal member 42 is inserted onto the bolt or spindle 47c with
its record engaging surface appropriately positioned to engage with the
record 45. Next, the other internal member 41 is inserted onto the bolt or
spindle 47c with its record engaging surface facing upwardly and a second
record 46 having warps is positioned on the record engaging surface of the
member 41 with the bolt 47c extending through the center hole of the
record 46. Finally, the upper member 10 is inserted onto the stack of
records and plate-like members with the bolt 47c extending through the
center aperture thereof. Next, a washer 47b is inserted onto the spindle
or bolt 47c and a wing nut 47a is threaded onto the bolt. Before the wing
nut 47 a is tightened, it is necessary for bolts 48c, 49c to be
respectively inserted each through one set of apertures about the
periphery of the apparatus. These apertures about the periphery of each
member correspond to the apertures 12a, 12b, 12c and 12d of FIG. 1, and
must first be brought into alignment and registration with each other so
that the bolts may be inserted therethrough. It is, of course, not
necessary to use exactly four holes or apertures as shown in FIG. 1, but
preferably three or more holes or apertures spaced equiangularly about the
periphery should be used. The apertures about the periphery may be
appropriately aligned by rotating the various members 10, 41, 42, 10,
about the central bolt or spindle 47c until one set of apertures such as
aperature 12a, align so that the bolt 48c may be inserted. A washer 48b is
then inserted onto the threads of the bolt 48c and a wing nut 48a is
threaded on to the bolt 48c. Similarly, a bolt 49c is then inserted into
another set of aligned peripheral apertures, such as aperture 12c, a
washer 49b is placed on the bolt and a wing nut 49a is threaded onto the
bolt 49c. Further bolts (not shown in FIG. 3) are then inserted in the
other sets of peripheral apertures 12b and 12d and washers and wing nuts
are threaded thereon.
With this arrangement, the bolts and wing nuts are then successively
tightened equally, starting with the center bolt and wing nut 47c and 47a.
As the bolts and wing nuts are tightened, the warpage of the records 45
and 46 will be removed due to the pressures and forces applied to the
records by the record engaging surfaces of the plate-like members of the
apparatus.
FIG. 4 shows an alternative embodiment of the apparatus of FIG. 3 for
performing the method of the invention. The difference as compared to the
apparatus of FIG. 3 is that the two interior plate-like members 41 and 42
of FIG. 3 have been replaced by the single interior member 20 previously
described with reference to FIG. 2B, and having upper and lower record
engaging surfaces. The upper and bottom, exterior, plate-like members in
FIG. 4 are each designated by numeral 10 and each correspond to the member
10 described with reference to FIG. 2A.
With this arrangement, it is seen that the apparatus is assembled by
insertion of the center bolt or spindle 47c through the center aperture of
the lower exterior member 10. A record 52 is then inserted onto the center
bolt 47c followed by the central plate-like member 20, followed by a
second record 54, followed by the upper plate-like member 10. A washer 47b
is then inserted onto the upper portion of the bolt or spindle 47c and a
wing nut 47a is threaded onto the bolt 47c. After this has been done,
bolts 48c, 49c and other bolts (not shown) are inserted through the
peripheral apertures in the apparatus after the peripheral apertures have
been aligned as previously described with reference to the embodiment of
FIG. 3. Correspondingly, washers 48b, 49b, etc. and wing nuts 48a, 49a,
etc. are inserted and threaded onto the peripheral bolts 48c, 49c, etc. In
operation, the central bolt and wing nut 47c is first tightened, and then
the peripheral bolts and wing nuts 48c, 48a, 49c, 49a, etc. are then
successively tightened. As the various wing nuts are successively
tightened, the warpage and surface irregularities on the records 52 and 54
are removed.
A still further embodiment of apparatus according to the present invention
is shown in FIG. 5 in which upper and lower exterior plate-like members 30
are used. As in the case of the other embodiments, the central bolt or
spindle 47c is first inserted through the center aperture of the lower
plate-like member 30, a warped record 60 is inserted onto the bolt 47c,
and the upper plate-like member is then inserted onto the center bolt 47c.
Next, a washer 47b is inserted onto the bolt 47c and a wing nut 47a is
threaded onto the bolt 47c. As in the case of the other embodiments, the
peripheral apertures are then aligned by appropriate relative rotation of
the upper member 30 and the lower member 30 and bolts 48c, 49c, etc. and
wing nuts 48a, 49a, etc. are inserted on the bolts 48c, 49c, etc.
In operation of the embodiment of FIG. 5, the peripheral bolts and wing
nuts are first tightened to cause the record engaging surfaces of the
upper and lower members 30 to engage the lip or lead-in portion of the
record 60 clamped therebetween. Next, the central bolt 47c and wing nut
47a are tightened in order to cause the warpage or surface irregularities
in the record 60 to be removed. It is noted that due to the bowed
condition of the members 30, as the central bolt and wing nut are
tightened, lateral (i.e., horizontal) forces, as well as vertical forces
are applied to the record 60.
It has been found that moderate external heat from an external heat source
(not shown) may be advantageously used with the embodiments in FIGS. 3, 4,
and 5. The application of moderate external heat causes the temperature of
the apparatus and the record or records therein to increase. This
facilitates the removal of warpages and surface irregularities from the
record(s) by causing the record(s), to become more pliant. Also, if the
external heat source is removed or turned off and the temperature of the
apparatus and the record(s) therein is permitted to return to ambient
temperature before the record(s) are removed from the apparatus, it has
been found that improved warpage removal is achieved. Any moderate
external heat source can be used to achieve this effect, including a light
bulb, sunlight, radiator, electrical heating coil, or warm oven.
With the apparatuses of FIG. 3 and FIG. 4, it is also possible, of course,
to add further internal plate-like members to allow simultaneous warpage
removal from a larger number of records.
It is also noted that the washers used with the apparatus preferably should
be selected to prevent unnecessary build-up pressure stresses within the
apparatus. For example, the washers under the wing nuts on the various
bolts should preferably be made of teflon, graphite, molybdenum
disulphide, or other suitable materials having low frictional
characteristics which would permit lateral sliding movement or expansion,
while maintaining vertical or tightening pressures or forces as the
various wing nuts and bolts are tightened.
Of course, all of the bolts, spindles, wing nuts, etc. and other elements
involved in the application of vertical pressures or forces should have
coefficients of expansion less than that of the materials used in the
various plate-like members in order to allow for the use of an external
heat source with the apparatus. Correspondingly, the plate-like members
should preferably be constructed of materials which have coefficients of
expansion at least equal to or greater than that of the polyvinyl
materials used in the phonograph records.
It will also be noted by those skilled in the art that the apparatus of the
present invention is readily adapted to be changed dimensionally, and, for
example, with the addition of accessories so that warps or surface
irregularities may be corrected in polyvinyl phonograph records of varying
sizes such as standard 12" records, 10" records, 7" records as well as
other size records.
Of course, the invention may be embodied in other specific forms without
departing from its spirit or essential characteristics. The present
embodiments, are therefore, to be considered in all respects as
illustrative and not restrictive, the scope of the invention being
indicated by the claims rather than by the foregoing description, and all
changes which come within the meaning and range of the equivalence of the
claims are therefore intended to be embraced therein.
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