U.S. patent application number 12/381231 was filed with the patent office on 2010-09-16 for cold cast mass element.
Invention is credited to Richard Chung, Zhi Wang.
Application Number | 20100229682 12/381231 |
Document ID | / |
Family ID | 42125760 |
Filed Date | 2010-09-16 |
United States Patent
Application |
20100229682 |
Kind Code |
A1 |
Chung; Richard ; et
al. |
September 16, 2010 |
Cold cast mass element
Abstract
A cold cast mass element has solid metal particles of greater
than 75% by volume and a binding agent of less than 25% by volume,
with an outside surface. The binding agent is exposed on the
outside surface and encapsulates the solid metal particles within
the cold cast mass element. The may have an outside surface has a
hardness of greater than durometer 70 Shore A and preferably has a
hardness of above about 75 Shore A or above about 100 Shore D. The
mass element has a binding agent which is an epoxy resin or
thermosetting phenol formaldehyde resin. The metal particles can be
grinded iron of preferably 85% to 96% by volume with a binding
agent 4% to 12% by volume. The mass element preferably has solid
metal particles of greater than 85% by weight; and a binding agent
of less than 15% by weight.
Inventors: |
Chung; Richard; (Rowland
Heights, CA) ; Wang; Zhi; (Taiyuan, CN) |
Correspondence
Address: |
LAW OFFICES OF CLEMENT CHENG
17220 NEWHOPE STREET #127
FOUNTAIN VALLEY
CA
92708
US
|
Family ID: |
42125760 |
Appl. No.: |
12/381231 |
Filed: |
March 10, 2009 |
Current U.S.
Class: |
75/230 |
Current CPC
Class: |
B22F 1/0059 20130101;
C08K 3/08 20130101; C08L 63/00 20130101; C08K 3/00 20130101; C09J
161/06 20130101 |
Class at
Publication: |
75/230 |
International
Class: |
C22C 38/00 20060101
C22C038/00 |
Claims
1. A cold cast mass element comprising: a. solid metal particles of
greater than 75% by volume; b. a binding agent of less than 25% by
volume; c. an outside surface, wherein the binding agent is exposed
on the outside surface and encapsulates the solid metal particles
within the cold cast mass element, wherein the outside surface has
a hardness of greater than durometer 70 Shore A.
2. The cold cast mass element of claim 1, wherein the cold cast
mass element outside surface has a hardness of above about 75 Shore
A.
3. The cold cast mass element of claim 1, wherein the binding agent
is an epoxy resin or thermosetting phenol formaldehyde resin.
4. The cold cast mass element of claim 1, wherein the solid metal
particles are grinded iron.
5. The cold cast mass element of claim 1, wherein the solid metal
particles are grinded iron of 85% to 96% by volume.
6. The cold cast mass element of claim 1, wherein the binding agent
is 4% to 12% by volume.
7. A cold cast mass element comprising: a. solid metal particles of
greater than 75% by volume; b. a binding agent of less than 25% by
volume; c. an outside surface, wherein the binding agent is exposed
on the outside surface and encapsulates the solid metal particles
within the cold cast mass element, wherein the outside surface has
a hardness of greater than durometer above about 100 Shore D.
8. The cold cast mass element of claim 7, wherein the cold cast
mass element has a hardness of above about 75 Shore A.
9. The cold cast mass element of claim 7, wherein the binding agent
is an epoxy resin or thermosetting phenol formaldehyde resin.
10. The cold cast mass element of claim 7, wherein the solid metal
particles are grinded iron.
11. The cold cast mass element of claim 7, wherein the solid metal
particles are grinded iron of 85% to 96% by volume.
12. The cold cast mass element of claim 7, wherein the binding
agent is 4% to 12% by volume.
13. A cold cast mass element comprising: a. solid metal particles
of greater than 85% by weight; b. a binding agent of less than 15%
by weight; c. an outside surface, wherein the binding agent is
exposed on the outside surface and encapsulates the solid metal
particles within the cold cast mass element, wherein the outside
surface has a hardness of greater than durometer 70 Shore A.
14. The cold cast mass element of claim 13, wherein the cold cast
mass element outside surface has a hardness of above about 75 Shore
A.
15. 1. The cold cast mass element of claim 13, wherein the cold
cast mass element outside surface has a hardness of above about 75
Shore A.
16. The cold cast mass element of claim 13, wherein the binding
agent is an epoxy resin or thermosetting phenol formaldehyde
resin.
17. The cold cast mass element of claim 13, wherein the solid metal
particles are grinded iron.
18. The cold cast mass element of claim 13, wherein the outside
surface has a hardness of greater than durometer above about 100
Shore D.
Description
BACKGROUND OF THE INVENTION
[0001] Mass elements such as flywheels, exercise weights and heavy
ballast for patio umbrella stands have traditionally been cast in
iron and then coated with a powder coating or paint. The mass
elements typically encompass inertial elements such as flywheels
which need to have structural rigidity, and weights such as patio
umbrella stands which need to be rigid and maintain wear resistance
in outdoor environments. Unfortunately, the hot casting process
which is a hot melting of iron requires heat and cannot be
performed at room temperature or at temperature which does not
require a heating element. The mass elements are sometimes coated
with a plastic housing, which requires an extra step.
[0002] Cold casting methods for high molecular weight polymers have
been described in the prior art such as in Johnson U.S. Pat. No.
5,602,197 issued Feb. 11, 1997. Johnson discloses in the abstract
that thermoplastic binder compositions comprising a high molecular
weight polymer component and a molten wax component are compounded
with sinterable ceramic or other inorganic powders. Upon cooling, a
thermally reversible gel is formed in the binder by the gelation of
the polymer in the molten wax. Ceramic batches comprising these
binders behave as shear-thinning and thermally reversible gels.
[0003] An example of a cold cast method is found in Cook U.S. Pat.
No. 6,005,041 issued Dec. 21, 1999, the disclosure of which is
incorporated herein by reference and provides for soft cold cast
articles that have a soft rubbery consistency. Cook teaches that a
variety of hard materials can be mixed into a resin for increasing
its strength. Cook uses oils to make a reinforced thermoplastic
elastomeric gel soft enough to be flexible for human wearing.
[0004] Bradshaw U.S. Pat. No. 5,446,085 issued Aug. 29, 1995
describes a composition comprising an inorganic filler and binder
component containing a glassy polymer and a rubbery polymer is
provided. The glassy polymer contacts and encapsulates the filler.
The compositions are especially useful in the fabrication of
flexible magnetic recording media and abrasive articles.
[0005] The Bradshaw reference is incorporated herein by reference
describes magnetic fillers suspended in polymeric compositions.
[0006] The processes currently used in the field of resin
composition materials science provides methods of strengthening a
resin with additives.
SUMMARY OF THE INVENTION
[0007] The present invention teaches certain benefits in
construction and use which give rise to the objectives described
below.
[0008] The present invention is a casting system or casting process
to manufacture low tolerance parts without heating up the cast
molds and thus at low cost. The material used to make parts using
the cast molds is a mixture of ground iron powder and a resin to
bond the iron powder together in a shape given in the cast molds.
Depending on the mixture ratio of the iron powder and the resin,
the mixture before curing could be as either a gel or dough. When
the mixture is as a gel, it could be injected into the mold through
an injection hole. When the mixture is as dough, it could be poured
into or dropped onto the cavity of the mold with the mold open.
After the mixture is set inside the mold, it is taken out of the
mold and set on a dry place to cure and harden. Because the process
and the mixture require almost no heating either on the mold or on
the part material before injection, the part cost is significantly
lower than the traditional casting processes, and the molding
process is simplified.
[0009] The process is for creating rigid articles, and is
specifically well-suited for nonstructural weights or mass or
inertial elements such as plate or dumbbell weights of durometer 70
Shore A and above to about 75 Shore A or 100 Shore D. The process
is also well suited for creating flywheels for apparatus such as
exercise machines. It is preferred to use the process to make
nonstructural weights or mass or inertial elements.
[0010] A cold cast mass element has solid metal particles of
greater than 75% by volume and a binding agent of less than 25% by
volume, with an outside surface. The binding agent is exposed on
the outside surface and encapsulates the solid metal particles
within the cold cast mass element. The may have an outside surface
has a hardness of greater than durometer 70 Shore A and preferably
has a hardness of above about 75 Shore A or above about 100 Shore
D. The mass element has a binding agent which is an epoxy resin or
thermosetting phenol formaldehyde resin. The metal particles can be
grinded iron of preferably 85% to 96% by volume with a binding
agent 4% to 12% by volume. The mass element preferably has solid
metal particles of greater than 85% by weight; and a binding agent
of less than 15% by weight.
[0011] A primary objective of the present invention is to provide a
system having advantages not taught by the prior art. Another
objective is to provide such a process system that helps reduce
manufacturing cost by eliminating heating process in the casting
process. Another objective is to provide such a casing process
system that accommodates a low-pressure injection or forming to
reduce wear and tear on the tooling. Another objective is to
provide such a system that eliminates a finish process such as
painting after the part is formed and dried.
[0012] Other features and advantages of the present invention will
become apparent from the following more detailed description, taken
in conjunction with the accompanying drawings, which illustrate, by
way of example, the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWING
[0013] The accompanying drawings illustrate the present invention.
In such drawings:
[0014] FIG. 1 is a perspective view of a first apparatus embodiment
for a cold casting process.
[0015] FIG. 2 is a second perspective view of the first
embodiment.
[0016] FIG. 3 is a perspective view of a second apparatus
embodiment for cold casting process.
[0017] FIG. 4 is another perspective view of the second
embodiment.
[0018] The following call out list of elements are used
consistently herein. [0019] 10 Cold Cast Apparatus [0020] 12 First
Cast [0021] 14 First Cast Block [0022] 16 First Cast Cavity Surface
[0023] 18 First Cast Injection Channel [0024] 40 Second Cast [0025]
42 Second Cast Block [0026] 44 Second Cast Cavity Surface [0027] 46
Second Cast Injection Channel [0028] 48 Vent Holes [0029] 60
Mandrel Assembly [0030] 62 Mandrel Base [0031] 64 First Mandrel
[0032] 66 Second Mandrel [0033] 68 Center Mandrel [0034] 70 Mandrel
Base Holes [0035] 80 Cast Housing [0036] 90 Cast Base [0037] 92
Base Plate [0038] 94 Base Plate Holes [0039] 96 Base Plate Slots
[0040] 100 Part
DETAILED DESCRIPTION OF THE INVENTION
[0041] The above described drawings FIGS. 1 and 4 illustrate the
invention, a cold cast apparatus 10 employing a cold casting or
molding process, comprising a first cast 12, a second cast 40, and
a part 100 made from the casting process. First cast 12 and second
cast 40 are half sides of the cast block as shown in FIGS. 1 and 2,
but they can also be parts of multi-side molds that have more than
two cast blocks to create an enclosure for cavity space for a part
shape. First cast 12 comprises a first cast block 14, a first cast
cavity surface 16 on first cast block 14, and a first cast
injection channel 18. Since the cold casting process does not
require a high pressure to mold the parts, first cast block 14 and
other mating cast blocks may not have to be of high strength tool
steel, but could be low cost material such as regular steel and
aluminum for relatively high volume productions, and clay or
hardened gypsum powder for low volume productions. On first block
14, first cast cavity surface is formed to match the shape of the
part on the side, as shown in FIG. 1, and first cast injection
channel 18 is placed to direct a mixture material from outside the
casting block into the cavity area of the cold cast apparatus.
[0042] Second cast 40 resembles first cast 12 in its features and
comprises a second cast block 42, a second cast cavity surface, and
a second cast injection channel. Second cast block 42 is usually
made of the same material as that of first cast block 14 but block
42 could be of a different material. In FIGS. 1 and 2, second cast
block 42 is made to mate with first cast block 14 to create a
complete cavity surface and space to make a part, however the mold
may comprise more than two cast blocks and inserts to complete the
cavity surface or space in other instances and applications. Second
cast cavity surface 44 forms the shape of the part on the
corresponding side and is a surface area or surface of the space
formed on second cast block 42. Second cast injection channel 46 is
also formed on second cast block 42 to put the mixture material
into the cavity area for forming the part. In the apparatus shown
in FIGS. 1 and 2, both first cast injection channel 18 and second
cast injection channel 46 come together, when both first cast block
14 and second cast block 42 comes together closing the cavity, to
form a hole for the material injection. Usually, the air inside the
enclosed cavity leaks out through the parting line between the cast
blocks as the mixture material is pushed into the cavity area, but
to help the air to escape completely, vent holes 48 are placed at
selective places around the mold to make sure there is no trapped
air inside the cavity while the mixture material fills the area or
space. The markings left on the part as the result of the vent
holes or parting line can be cleaned after the casting process.
[0043] The mixture material for a part 100 is made of iron powder
and a resin for bonding the iron powder. The iron powder is
preferably from 300 micron to 1000 micron, but the process also
works for smaller sized particles as small as sub micron diameter.
Depending on the ratio of the mixture between the iron powder and
the resin, the mixture may come out more as a thick gel or dough.
When the mixture is a thick gel, it may be injected through cast
injection channels 18, 46 to the cavity to form part 100. When the
mixture is dough, it may be put into the cavity with the mold open,
and closing the mold forms the part. In this case of using
dough-like mixture, cast injection channels 18, 46 may be omitted
from cast blocks 14, 42. Because cold casting process does not
require heating up the castings to sinter or to melt the material,
it takes at least a few minutes to cure the part. Some heat, not as
much as that for sintering or melting, may help to speed
solidifying the part inside the castings before it is taken out of
the mold. The parts are usually taken out of the mold for complete
curing.
[0044] Main ingredient for the mixture for the part is powered
metal, such as iron powder, that can be easily made without melting
process from scrap metals, such as iron or steel scraps, and even
ores. The adhesive binding agent mixed with the powered metal can
be epoxy resin or thermosetting phenol formaldehyde resin with its
proportion range from 4% to 12%, which would mean that the powdered
metal percentage is preferably in the proportion range of 88% to
96% by volume. The percentage of metal by volume can also be as low
as 75%. Also other adhesive types may also be used to hold the
metal particles in the shape formed by the casting. If calculating
the amount of iron by weight, it would be approximately at least
89% by weight in the preferred range. The present method is also
effective for iron particles of 85% or more by weight.
[0045] FIGS. 3 and 4 show a second casting apparatus that is
similar to the first casting apparatus in terms of making the part
pattern but has a slightly different structure such that it is
possible to open the cast and directly pour the material into the
cavity and close the cast rather than pushing the mixture through
an injection hole. The second casting apparatus comprises a mandrel
assembly 60 comprising a mandrel base 62 to support a first mandrel
64, a second mandrel 66, and a center mandrel 68. The mandrels are
basically long shafts extended out from mandrel base 62 to put
through cast blocks and the part to form the holes of the mandrel
shapes in the part as shown in FIGS. 3 and 4. Second cast block 42
having the shape pattern of one side of the part is put through
mandrel assembly 60 with its pattern side facing away from mandrel
base 62. And both mandrel assembly 60 and second cast block 42 are
inserted into a cast housing 80 that provides, in this apparatus, a
sidewall pattern for the part. The mixture for the part is then
poured over the second cast block, and the cast can now be closed
with first cast block 14 inserted into cast housing 80 with its
patterned side facing toward the mixture. With some pressure over
the first cast block, the mixture is formed to the shape of the
cavity created by the cast blocks, the mandrel shafts, and the cast
housing. A good advantage of this casting system is that the amount
of the mixture poured into the cast does not have to be exact: The
cast blocks naturally accommodate different amounts of the mixture
that means without using different tooling, the parts of different
thickness can be manufactured in a single setup.
[0046] The second casting apparatus shown in FIGS. 3 and 4 further
comprises a cast base 90 supporting cast housing 80 and mandrel
assembly 60. Cast base 90 comprises a base plate 92 that is
basically a flat structure, a base plate slots 96 that is a set of
slot holes on base plate 92 to clamp down and position cast housing
80 on base plate 92, and a base plate holes that a number of holes
in base plate 92 to insert pins to help ejecting mandrel assembly
60 from cast housing 80. Also mandrel assembly 60 further comprises
a mandrel base holes 70 that is a set of holes on mandrel base 62
for the pins to go through to eject cast blocks 14, 42 with or
without part 100.
[0047] Even though a low pressure to merely to force the mixture
into the shape of the casting is sufficient to produce the part
without causing too much wear and tear on the tooling, but a
relatively high pressure, near 500 kilogram per square millimeter,
may be applied to make the part more dense by squeezing out all the
air bubbles in the mixture. Alternatively, no pressure which is
very light hand pressure can be applied in instances where a bubble
formation is not a problem.
[0048] The process through the first apparatus and second apparatus
is ideal for producing parts that are structurally non-critical and
low tolerance and that need some mass built in and be formed to
particular shapes quickly. One such part is a barbell weight plate
as part 100 as shown in FIGS. 1 and 2. Traditionally barbell
weights are made from casting using iron powder sintered or molten
iron poured into the casting. The parts such as barbell weights
produced in the traditional casting process comprise nearly all
iron as their material yield a good weight density for weight
lifting exercises. Since cold casting process requires the resin as
the bonding material for the iron powder in the mixture, the weight
density for the parts made from cold casting is not quite as heavy
as the weight parts made from the traditional casting process.
However, cold casting process cuts or takes out the significant
amount of heat from the traditional casting process and thus saves
the heating cost from the casting process. Also the parts made from
cold casting are naturally glossed gray in color on the exterior
eliminating the process of rust proofing or painting the part after
the casting process. Since the process cuts both significant amount
of heating during the casting process and applying finishing on the
part after curing, it is an environmentally friendly process.
[0049] The process is preferably completed at room temperature, or
whatever temperature the workspace is. If the end product is heated
after molding, the end product can be cured faster, however it is
preferred to have the entire process completed at room temperature.
After the end product is completed, it would have hardness of a
tofu or gelatin desert. In about 15 minutes, the resin outside of
the product cures and the product is relatively rigid. The hardness
of the final article outside surface is preferably about durometer
70 Shore A and above to about 75 Shore A or 100 Shore D. The
outside surface is protected by and preferably encapsulated by the
binding agent which is exposed on the outside surface so that it
covers the solid metal particles within the cold cast mass
element.
[0050] Although the invention has been disclosed in detail with
reference only to the embodiments shown above, those skilled in the
art will appreciate that various other embodiments can be provided
without departing from the scope of the invention. Accordingly, the
invention is defined only by the claims set forth below.
* * * * *