U.S. patent application number 15/435344 was filed with the patent office on 2018-07-12 for toy dart.
The applicant listed for this patent is Alex Brands Buzz Bee Toys (HK) Limited. Invention is credited to Chor-Ming Ma.
Application Number | 20180195842 15/435344 |
Document ID | / |
Family ID | 62749508 |
Filed Date | 2018-07-12 |
United States Patent
Application |
20180195842 |
Kind Code |
A1 |
Ma; Chor-Ming |
July 12, 2018 |
Toy Dart
Abstract
The invention relates to a dart head for a toy dart, comprising
a body having a hollow stem portion integrally formed with and
longitudinally extending from an enlarged, hollow head portion; the
head portion and the stem portion being fluidly connected, with the
head portion defining at least one first transverse internal head
dimension, and the stem portion defining at least one first
transverse internal stem dimension; wherein the at least one first
transverse internal head dimension is larger than the at least one
first transverse internal stem dimension. The invention also
relates to a toy dart comprising a dart body connectable with the
dart head as described, and a method of manufacturing the dart head
as described.
Inventors: |
Ma; Chor-Ming; (Kowloon,
HK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Alex Brands Buzz Bee Toys (HK) Limited |
Kowloon |
|
HK |
|
|
Family ID: |
62749508 |
Appl. No.: |
15/435344 |
Filed: |
February 17, 2017 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
15402767 |
Jan 10, 2017 |
|
|
|
15435344 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29L 2031/5209 20130101;
F42B 6/003 20130101; F42B 6/08 20130101; B29C 45/4407 20130101 |
International
Class: |
F42B 6/00 20060101
F42B006/00; B29C 45/43 20060101 B29C045/43 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 6, 2017 |
HK |
17100179.4 |
Claims
1. A dart head for a toy dart, comprising: a body having a hollow
stem portion integrally formed in a single, continuous piece with
and longitudinally extending from an enlarged, hollow head portion;
the head portion and the stem portion being fluidly connected, with
the head portion defining at least one first transverse internal
head dimension, and the stem portion defining at least one first
transverse internal stem dimension; wherein the at least one first
transverse internal head dimension being larger than the at least
one first transverse internal stem dimension; wherein at least the
hollow stem portion of the body is formed of a resilient material,
said material being sufficiently resilient to enable the hollow
stem portion to be inflated by a fluid to define at least one
second transverse internal stem dimension which is larger than the
first transverse internal head dimension.
2. (canceled)
3. The dart head according to claim 1, wherein the hollow head
portion of the body is formed of the same resilient material as the
hollow stem portion, such that the hollow head portion is
inflatable by a fluid to define at least one second transverse
internal head dimension which is larger than the first transverse
internal head dimension.
4. The dart head according to claim 1, wherein the fluid comprises
a pressurized gas.
5. The dart head according to claim 3, wherein the hollow head
portion and the hollow stem portion, once inflated, are resiliently
restorable to their uninflated dimensions, when the fluid is
released.
6. The dart head according to claim 1, wherein the hollow head
portion is resilient such that, upon impact on a surface, the head
portion is adapted to resiliently deform to thereby increase area
of contact between the head portion and the surface.
7. The dart head according to claim 1, wherein the body is formed
of a resilient polymeric material.
8. The dart head according to claim 1, further comprising an insert
adapted to be received at the hollow stem portion of the body.
9. The dart head according to claim 8, wherein the insert is
partially hollow.
10. The dart head according to claim 8, wherein the insert
comprises a weight member.
11. A toy dart comprising a dart body connectable with the dart
head in accordance with claim 1.
12. The toy dart according to claim 11, wherein the dart body is
formed of at least one foam material.
13. The toy dart according to claim 11, wherein the dart body is
partially hollow.
14. The toy dart according to claim 11, wherein the dart body is
adapted to receive the stem portion of the dart head to thereby
connect with the dart head.
15. A method of manufacturing the dart head according to claim 1,
comprising the steps of: providing a male mold and a female mold;
injecting a flowable polymer between the male mold and the female
mold; solidifying the polymer between the male mold and the female
mold to form a molded polymer; separating the female mold from the
molded polymer; resiliently expanding the molded polymer to form an
expanded molded polymer, the expanded molded polymer having at
least one internal cavity with a size larger than the male mold;
and detaching the molded polymer from the male mold dart head to
form a molded polymer dart head.
16. The method of manufacturing the dart head according to claim
15, wherein the resiliently expanding step comprises introducing a
fluid into the molded polymer to inflate at least a stem portion of
the molded polymer.
17. The method of manufacturing the dart head according to claim
16, wherein the fluid comprises a pressurized gas.
18. The method of manufacturing the dart head according to claim
17, wherein the detaching step comprises blowing off the expanded
molded polymer from the male mold by use of the pressurized
gas.
19. The method of manufacturing the dart head according to claim
17, wherein the pressurized gas is introduced via a gas outlet
arranged at the male mold.
20. The method of manufacturing the dart head according to claim
15, further comprising a step of providing a restricting means to
surround the molded polymer prior to the resiliently expanding
step.
Description
[0001] This application is a continuation-in-part utility patent
application claiming priority to U.S. patent application Ser. No.
15402767 filed Jan. 10, 2017, and which is incorporated by
reference herein for all purposes.
FIELD OF THE INVENTION
[0002] The invention relates to a toy projectile and, particularly,
but not exclusively, to a foam dart for use in a toy such as a toy
gun.
BACKGROUND OF THE INVENTION
[0003] A large variety of toy launchers for projectiles such as
bullets, darts, arrows or the like are available in the market.
Among the various designs, a foam dart, which typically comprises a
shaft or a body made of foam material connecting with a rigid head
portion, has been gaining increasing popularity among both children
and adult players due to their light weight and relatively low risk
of injury especially when compared with the traditional darts which
are very often formed of hard, solid plastic materials.
Particularly, toy foam darts have been designed with functional
features in order to improve aerodynamic flight properties, safety,
as well as to enhance user's experience during a play.
OBJECTS OF THE INVENTION
[0004] An object of the present invention is to provide a novel
foam dart for use with a toy.
[0005] Another object of the present invention is to provide a toy
dart with a reduced or cushioned force of impact on a target to
thereby enhance safety.
[0006] A further object of the present invention is to mitigate or
obviate to some degree one or more problems associated with known
toy projectiles, or at least to provide a useful alternative.
[0007] The above objects are met by the combination of features of
the main claim; the sub-claims disclose further advantageous
embodiments of the invention.
[0008] One skilled in the art will derive from the following
description other objects of the invention. Therefore, the
foregoing statements of object are not exhaustive and serve merely
to illustrate some of the many objects of the present
invention.
SUMMARY OF THE INVENTION
[0009] In a first main aspect, the invention provides a dart head
for a toy dart. The toy dart comprises a body having a hollow stem
portion integrally formed with and longitudinally extending from an
enlarged, hollow head portion; the head portion and the stem
portion being fluidly connected, with the head portion defining at
least one first transverse internal head dimension, and the stem
portion defining at least one first transverse internal stem
dimension; wherein the at least one first transverse internal head
dimension is larger than the at least one first transverse internal
stem dimension..
[0010] In a second main aspect, the invention provides a toy dart
comprising a dart body connectable with the dart head in accordance
with the first main aspect.
[0011] In a third main aspect, the invention provides a method of
manufacturing the dart head according to the first main aspect. The
method comprises the steps of providing a male mold and a female
mold; injecting a flowable polymer between the male mold and the
female mold; solidifying the polymer between the male mold and the
female mold to form a molded polymer; separating the female mold
from the molded polymer; resiliently expanding the molded polymer
to form an expanded molded polymer, the expanded molded polymer
having at least one internal cavity with a size larger than the
male mold; and detaching the molded polymer from the male mold dart
head to form a molded polymer dart head.
[0012] The summary of the invention does not necessarily disclose
all the features essential for defining the invention; the
invention may reside in a sub-combination of the disclosed
features.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The foregoing and further features of the present invention
will be apparent from the following description of preferred
embodiments which are provided by way of example only in connection
with the accompanying figure, of which:
[0014] FIG. 1A shows a dart head and a dart body for a toy dart
according to an embodiment of the present invention prior to
connection;
[0015] FIG. 1B shows the dart head and the dart body of FIG. 1A
after connection to form a toy dart;
[0016] FIG. 2A shows a dart head and a dart body for a toy dart
according to a second embodiment of the present invention prior to
connection;
[0017] FIG. 2B shows the dart head and the dart body of FIG. 2A
after connection to form a toy dart;
[0018] FIG. 3A shows a dart head, an insert and a dart body for a
toy dart according to a third embodiment of the present invention
prior to connection;
[0019] FIG. 3B shows the dart head, the insert and the dart body of
FIG. 3A after connection to form a toy dart;
[0020] FIG. 4A shows a dart head, an insert and a dart body for a
toy dart according to a fourth embodiment of the present invention
prior to connection;
[0021] FIG. 4B shows the dart head, the insert and the dart body of
FIG. 4A after connection to form a toy dart;
[0022] FIG. 5A shows a dart head and an insert for a toy dart
according to a fifth embodiment of the present invention prior to
connection;
[0023] FIG. 5B shows the dart head, the insert of FIG. 5A and the
dart body after connection to form a toy dart;
[0024] FIG. 6 shows the deformation of the embodied dart heads
according to the present invention upon impact on a surface;
[0025] FIG. 7 shows a method of manufacturing a dart head according
to an embodiment of the present invention;
[0026] FIG. 8 shows another method of manufacturing a dart head
according to an embodiment of the present invention;
[0027] FIG. 9A to FIG. 9G show the method steps of manufacturing a
dart head according to a further embodiment of the present
invention;
[0028] FIG. 10A to FIG. 10G show the method steps of manufacturing
a dart head according to a further embodiment of the present
invention; and
[0029] FIG. 11A to FIG. 11H show the method steps of manufacturing
a dart head according to a further embodiment of the present
invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0030] The following description is of preferred embodiments by way
of example only and without limitation to the combination of
features necessary for carrying the invention into effect.
[0031] Reference in this specification to "one embodiment" or "an
embodiment" means that a particular feature, structure, or
characteristic described in connection with the embodiment is
included in at least one embodiment of the invention. The
appearances of the phrase "in one embodiment" in various places in
the specification are not necessarily all referring to the same
embodiment, nor are separate or alternative embodiments mutually
exclusive of other embodiments. Moreover, various features are
described which may be exhibited by some embodiments and not by
others. Similarly, various requirements are described which may be
requirements for some embodiments but not other embodiments.
[0032] Referring to FIGS. 1A and 1B, shown is an embodiment of the
toy dart 10 according to the present invention. The toy dart 10 may
comprise a dart body 30 connectable with a dart head 20. In one
embodiment, the dart head 20 is receivably connectable with the
dart body 30 via an at least partially hollow, bore portion 32 of
the dart body 30. Preferably, the dart body 30 is formed of at
least one foam material such as, but not limited to, polyurethane,
polyethylene, polystyrene or melamine foams, etc.
[0033] In this embodiment, the bore portion 32 of the dart body 30
extends the length of the dart body 30, although it needs not do
so. The bore portion 32 of the dart body 30 is adapted to receive
at least partially a stem portion 22 of the dart head 20 to thereby
connect the dart body 30 with the dart head 20. Specifically, the
dart head 20 comprises a body 23 having an enlarged head portion 24
integrally formed with the stem portion 22. The stem portion 22 is
configured to longitudinally extend from the head portion 24. The
head portion 24 is hollow to define at least one head cavity 26. In
the context of this description, the expression "integrally formed"
relates to a continuous material formation of the dart head body 23
having the head portion 24 and the stem portion 22 in a single
piece, without the need of joining, adhering or any other form of
connecting the head portion 24 and the stem portion 22 together
after the respective head and stem portions are formed
together.
[0034] In one embodiment, the stem portion 22 is also at least
partially hollow to define at least one stem cavity 28, such that
the at least one head cavity 26 of the hollow head portion 24 and
the at least one stem cavity 28 of the hollow stem portion 22 can
be arranged to be in a continuous, fluid communication. The dart
head 20 is open at a rear end opening 27 of the stem portion 22 to
form an undercut.
[0035] As shown in FIGS. 1A and 1B, the head portion 24 can be
configured substantially in a hemispherical shape, with a flat,
head base portion 25 adapted to abut a leading edge 35 of the dart
body 30. The stem portion 22 is adapted to be snugly received by
the bore portion 32 of the dart body 30 when the dart head 20 is
arranged to connect with the dart body 30. FIGS. 2A and 2B, 3A and
3B, 4A and 4B, and 5A and 5B further show a number of embodiments
of the dart head 20 in alternative configurations such as, but not
limited to, in a shape of a conical frustum (see FIGS. 2A and 2B;
3A and 3B, and 5A and 5B), or cylindrical shape (see FIGS. 4A and
4B). The shape of the dart head is found to contribute to the
flight performance of the resulting foam dart. For example, a dart
with a cylindrically-shaped dart head is capable of achieving
higher stability and thus better accuracy during shooting. While a
dart with a conical frustum-shaped dart head may be able to fly
further in air and thus a longer shooting distance due to the
reduced forward-facing surface for air friction, but it is found to
be less stable than the dart with a cylindrical dart head. This may
be attributed to the relatively larger side pushing force or air
dragging effect by the tapered wall of the conical frustum-shaped
dart head during the flight.
[0036] The dart head 20 may optionally comprise an insert 40
adapted to be received in the hollow stem portion 22 of the dart
head body 23. Specifically, the insert 40 is configured to be
received and to extend at least partially along a length of the
hollow stem portion 22. For example, FIGS. 3A and 3B, and 4A and 4B
show the arrangement of the hollow stem portions 22 being partially
filled by the respective inserts 40 starting from their rear end
openings 27.
[0037] FIGS. 5A and 5B further show the arrangement of the hollow
stem portion 22 as being substantially filled by the insert 40
along its length. The insert 40 can be solid or at least partially
hollow, as shown in FIGS. 3A, 3B and 4A, 4B, respectively.
Preferably, the insert 40 may comprise a weight member to provide
additional weight to the dart 10 to thereby adjust or customize the
flight performance of the dart. For example, a higher accuracy can
be achieved by a relatively heavier dart due to its being less
susceptible to the interfering air flow, but also a lower speed or
acceleration of the dart due to its weight. However, a dart with
lighter weight will be more susceptible to the surrounding air
friction which not only results in lower shooting accuracy but also
a shorter shooting distance. In one specific embodiment, it is
found that a foam dart 10 with the dart body 30 having an external
diameter of about 12 mm to about 13 mm, a length of the dart 10 of
about 6 cm to 8 cm, and an overall weight of about 0.9 gram to 1.2
gram achieves a good balance between shooting distance, stability
and thus shooting accuracy, although a person skilled in the art
would appreciate that any variations and/or customizations to the
configuration and/or dimension of the dart shall be encompassed, as
long as they are considered suitable and applicable to the present
invention without departing from the inventive concept.
[0038] In one embodiment, the insert 40 may provide additional
support to the hollow stem portion 22 thereby assisting and/or
improving engagement and/or adhesion between the outer wall surface
of the stem portion 22 of the dart head 20 and the inner wall
surface of the bore portion 32 of the dart body 30.
[0039] As more clearly shown in FIGS. 5A and 5B, the insert 40 may
comprise a flange 42 at an end distal to the dart head 20. When the
insert 40 is received into the cavity 28 of the stem portion 22,
the flange 42 is adapted to abut the annular end wall 29 of the
rear end opening 27 of the stem portion 22 to thereby position the
insert 40 at or adjacent the open end 27, with the head portion 24
remaining hollow.
[0040] Particularly, the hollow head portion 24 is of sufficient
resiliency such that, upon impact on a surface such as a target,
the head portion 24 is adapted to resiliently deform, flatten or
collapse to thereby increase the area of contact, i.e. the impact
surface between the head portion 24 of the dart 10 and the target,
as shown in the examples of FIG. 6. The increase in impact area due
to the deformed or flattened head portion 24 is particularly
advantageous in reducing the force of impact on the target struck
by the dart, which significantly enhances the safety of the game.
The deformation of the head portion 24 during an impact cushions
the blow of the dart on the impact surface. The fluid communication
between the head cavity 26 and the hollow stem portion 22 enhances
the cushioning effect even in the case where the hollow stem
portion has received a weighted insert 40. Where the weighted
insert 40 also has a longitudinally extending bore, the diameter of
this bore may be selected to exercise a degree of control on the
rate of the cushioning effect by controlling the rate of fluid
communication between the head cavity 26 and the hollow stem
portion 22.
[0041] Preferably, the hollow head portion 24 may define at least
one first transverse internal head dimension (D.sub.1) of the head
cavity 26, and the hollow stem portion 22 defines at least one
first transverse internal stem dimension (D.sub.2) of the stem
cavity 28, with the first transverse internal head dimension
(D.sub.1) being larger than the first transverse internal stem
dimension (D.sub.2), as shown in FIG. 5A. This preferred
configuration is found to facilitate the deformation of the head
portion 24 for increasing the contact surface area with the target
during an impact. The volume of the head cavity 26 is preferably
larger than the volume of the bore or cavity in the hollow stem
portion 22.
[0042] The head portion 24 can be formed of one or more resilient
polymeric materials such as, but not limited to, polyurethane
foams, poly(ethylene-vinyl acetate), polyvinyl chloride, resins
and/or a mixture thereof. In one embodiment, the integrally formed
body 23 of the dart head 20 can also be is formed by molding of the
one or more of these resilient polymeric materials, for example,
blow molding, injection molding, roto-casting (also known as
rotational molding) or the like. Examples of blow molding and
injection molding of the dart heads are shown in FIGS. 7 and 8,
respectively. FIGS. 9A to 9G illustrate an exemplified injection
molding method for manufacturing the dart head of the present
invention. Referring to FIG. 9A, shown is the step of providing a
male mold 50 and a female mold 60 having at least a first female
mold part 62 and a second female mold part 64. In this embodiment,
the male mold 50 is movably connected at the second female mold
part 64, and preferably, the male mold 50 is at least partially
received at the second female mold part 64 and is slidably movable
in a direction back and forth relative to the first female mold
part 62.
[0043] The male mold 50 may comprise at least one male mold member
52. In this embodiment, the male mold member 52 preferably
comprises an enlarged head connected with an elongated stem. The
enlarged head is configured to conform substantially in shape with
the first female mold part 62, and the elongated stem is configured
to conform substantially in shape with the second female mold 64
part for molding the dart head.
[0044] To begin the molding process, the first and the second
female mold parts 62, 64 are brought to a close position which
allows the male mold member 52 to be substantially encased within a
molding cavity 65 defined by the first and the second female mold
parts 62, 64, as shown in FIG. 9B. Subsequently, a flowable polymer
is injected into the cavity 65 between the male and the female
molds 50, 60 via an inlet 66, as shown in FIG. 9C. The polymer will
flow over the male mold member 52 and eventually fill up the cavity
65 to integrally form the dart head 20 having the hollow enlarged
head portion 24 and the hollow stem portion 22 having an undercut
opening 27 at the end of the stem portion 22.
[0045] The flowable polymer can be one or more of the resilient
polymeric materials as described above, such as, but not limited
to, polyurethane foams, poly(ethylene-vinyl acetate), polyvinyl
chloride, resins and/or a mixture thereof in their melted or
solution form. A person skilled in the art would appreciate that
the present invention should not be limited to the described
examples of the flowable or resilient polymeric materials, but any
other flowable or resilient materials which is considered
applicable and suitable for the present application, should also be
encompassed.
[0046] After the polymer is solidified between molds 50, 60, the
second female mold part 64 and the male mold 50 will be moved away
from the first female mold part 62. As the solidified, molded
polymer is retained at the male mold member 52 of the male mold 50,
the movement of the second female mold part 64 away from the first
female mold part 62 will thus separate the molded polymer from the
first female mold part 62, as shown in FIG. 9D. Alternatively, this
step may also be performed by moving the first female mold part 62
away from the male mold 50 and the second female mold part 64. The
molded polymer can then be mechanically released or discharged from
the second female mold part 64 and the male mold member 52 of the
male mold 50.
[0047] Preferably, the mechanically releasing step can be conducted
in a two-steps process. First, with the second female mold part 64
remains stationary, the male mold 50, which has been movably
engaged at the second female mold part 64, can be arranged to slide
forward and away from the second female mold part 64 to disengage
the molded polymer from the second female mold part 64.
Alternatively, the male mold 50 may remain stationary but with the
second female mold part 64 moving backward and away from the male
mold member 52 to thereby disengage the molded polymer from the
second female mold part 64, see FIG. 9E.
[0048] The male mold 50 preferably comprises a pushing means 55
adapted to mechanically push the molded polymer off of the mold
member 52 of the male mold 50. In one embodiment, the pushing means
55 is sleevably arranged at an end of the elongated stem of the
male mold member 52, with its leading end abutting the open end 27
of the molded, polymer dart head. In the second step, the pushing
means 55 will be arranged to move towards the molded polymer to
thereby mechanically push it off of the male mold member 52 over
the open end 27, see FIGS. 9F and 9G. It is important that the
molded polymer is of sufficient resiliency such that the molded
dart head 20, especially the narrow stem portion 22 and the
undercut opening 27, is resilient enough to deform to thereby slide
or pass over the enlarged head of the male mold member 52 (see FIG.
9F), such that it can be released from the male mold 50 upon the
mechanical pushing by the pushing member 55 without breaking apart.
The molded polymer should also be resilient enough to restore its
original molded shape after the release (see FIG. 9G). It is also
found that a male mold member 52 having an enlarged head with
rounded corners will facilitate the mechanical releasing
process.
[0049] FIGS. 10A to 10G illustrates a similar process to that of
FIGS. 9A to 9G, with the two-steps of mechanically releasing the
molded polymer being assisted by an electric solenoid, by way of
example, although a person skilled in the art would understand that
the mechanical pushing or releasing can also be achieved by some
other known means, such as, but not limited to, pneumatic,
hydraulic and/or motor systems as well as other mechanical
linkages.
[0050] Referring to FIG. 10A, shown is the step for the first and
the second female mold parts 62, 64 as being brought together to a
closely adjacent position to substantially encase the male mold
member 52 in the molding cavity 65. A flowable polymer will then be
injected into the cavity 65 via an inlet 66, as shown in FIG. 10B.
After solidification, a molded polymer dart head integrally formed
with an enlarged head portion 24 and a stem portion 22 with an
undercut opening 27 at its end will be formed.
[0051] The second female mold part 64 and the male mold 50 will
then be arranged to move away from the first female mold part 62,
with the solidified, molded polymer being retained at the male mold
member 52 of the male mold 50, as shown in FIG. 10C.
[0052] To begin the two-steps of the mechanically releasing
process, the second female mold part 64 will first be arranged to
engage with the electric solenoid 70 via one or more mechanical
linkages, as shown in FIG. 10D. In this embodiment, the second
female mold part 64 is adapted to slide backward, i.e. towards the
solenoid 70 and away from the mold member 52 to thereby disengage
the molded polymer from the second female mold part 64, see FIG.
10E. In the next step, the electric solenoid 70 will be actuated to
impose a strong mechanical push via a pusher 72 towards the pushing
means 55 to thereby mechanically push the molded polymer off of the
mold member 52 of the male mold 50 via the undercut opening 27 of
the molded dart head 20, as seen in FIGS. 10F and 10G. Again, it is
essential for the molded polymer to be of sufficient resiliency
such that the dart head 20 is resilient enough for the narrow step
portion 24 and the undercut opening 27 to be deformable to thereby
slide or pass over the enlarged head of the male mold member 52
(see FIG. 10F). The resiliency of the molded polymer also allows
the released dart head 20 to quickly or instantly restore its
original molded shape, without any tearing, ripping or fractures to
the structure (see FIG. 10G).
[0053] In yet another embodiment, the dart head 20 of the toy dart
10 may have at least the hollow stem portion 22 of the integrally
formed body 23 being made up of a material of sufficient
resiliency, such that the stem portion 22 can be resiliently
expandable or inflatable by, for example, a fluid stream such as
but not limited to, pressurized gas or air introduced or injected
into the body 23. The inflated stem portion 22 may define at least
one second transverse internal stem dimension (D.sub.4), which is
larger than the first transverse internal head dimension (D.sub.1).
Preferably, the hollow head portion 24 of the integrally formed
body 23 may be formed of the same resilient material or different
material but of similar resiliency to that of the hollow stem
portion 22, such that the head portion 24 is also expandable or
inflatable by the inflating fluid stream to define at least one
second transverse internal head dimension (D.sub.3), with the
second transverse internal head dimension (D.sub.3) being larger
than the first transverse internal head dimension (D.sub.1).
[0054] Once the inflating fluid stream is removed or released, the
sufficient resiliency of the material or materials allow the
inflated stem portion 22 or the inflated body 23 to resiliently
restore to their original, uninflated dimensions, i.e. from the
second transverse internal head dimension (D.sub.3) to the first
transverse internal head dimension (D.sub.1); and from the second
transverse internal stem dimension (D.sub.4) to the first
transverse internal stem dimension (D.sub.2), without any tearing,
ripping or fractures to the structure.
[0055] The resiliency and the inflatable nature of the stem portion
22 or the body 23 of the dart head 20 is of particular significance
to allow manufacturing of the dart head 20 by an pressurized
air-assisted, injection molding process according to the present
invention. Similar to the above described processes of FIGS. 9A to
9G and 10A to 10G, the pressurized air-assisted process negates the
manual releasing or detaching step of the molded dart head from the
mold, and more specifically, the male mold after the molding
process. An embodiment of the pressurized air-assisted, injection
molding process of the present invention is illustrated in FIGS.
11A to 11H, and is described below.
[0056] FIG. 11A shows the step for the female mold 60, which
comprises the first and the second female mold parts 62, 64, as
being brought together to a closely adjacent position to
substantially encase the male mold member 52 of the male mold 50 in
the molding cavity 65. A flowable polymer will then be injected
into the cavity 65 via an inlet 66 for molding, as shown in FIG.
11B. After solidification, a molded polymer dart head integrally
formed with an enlarged head portion 24 and a stem portion 22 with
an undercut opening 27 at its end will be formed.
[0057] The second female mold part 64 and the male mold 50 will
then be arranged to move away from the first female mold part 62,
with the solidified, molded polymer dart head 20 being retained at
the male mold member 52 of the male mold 50, as shown in FIG. 11C.
In this embodiment, the movement of the second female mold part 64
and the male mold 50 away from the first female mold part 62 also
detaches the unwanted, residual molded parts such as the sprue 31
from the molded dart head 20. This automatic and mechanical
detaching step is advantageous to negate any secondary, manual
degating step to detach the sprue 31 from the molded dart head 20.
The detached sprue 31 may further be released and discarded by, for
example, mechanically separating the first female mold part 62 from
the sprue 31, as shown in FIG. 11C, and subsequently, mechanically
pushing the sprue 31 off from the inlet 66, as shown in FIG.
11E.
[0058] In this specific embodiment, the male mold 50 and
preferably, the male mold member 52 of the male mold 50 is provided
with a nozzle or gas outlet 51 adapted to inject or introduce a
fluid stream such as pressurized gas or air into the internal
cavity of the molded dart head 20, i.e. the fluidly connected head
cavity 26 of the head portion 24, and the stem cavity 28 of the
stem portion 22. Particularly, the integrally formed body 23 of the
molded dart head 20 is of sufficient resiliency, such that it can
be resiliently expanded by the injected pressurized air, and thus
detached from the surface of the male mold 50. FIGS. 11F and 11G
show the expansion of the dart head body 23 by the injected
pressurized air, with the first transverse internal head dimension
(D.sub.1) of the internal cavity expanded to become the second
transverse internal head dimension (D.sub.3), and the first
transverse internal stem dimension (D.sub.2) of the internal cavity
expanded to become the second transverse internal stem dimension
(D.sub.4). Preferably, the expanded internal cavity has a size
larger than the male mold 50, and more specifically, the enlarged
head of the male mold member 52 of the male mold 50. The emission
of the pressurized air further provides a pushing force to
effectively blow the expanded dart head body 23 off from the male
mold 50, as shown in FIG. 11H, without the need of any secondary,
manual detaching or mechanical pushing steps.
[0059] Optionally, a restricting means 67 can be provided to
surround the molded polymer dart head 20 to restrict or limit the
expansion or inflation of molded dart head 20 prior to the
inflation step. For example, the restricting means 67 can be
arranged in the form of a cylindrical tube which surrounds and
extends along the length of the dart head body 23, as shown in, for
example, FIGS. 11D to 11H. The cylindrical restricting means 67 may
comprise an internal wall spaced from the dart head body 23 for a
sufficient distance, such that the body 23 can be inflated to a
sufficient extent to overcome the enlarged head of the male mold
member 52. At the same time, the cylindrical restricting means 67
is adapted to prevent the molded dart head body 23 from being
overly inflated which may lead to eruption of the body 23. The
restricting means 67 may further be provided with a switch or a
sensor, such as a touch sensor triggerable to discontinue the gas
supply when the body 23 is expanded to a required size to be in
contact with the internal wall of the restricting means 67, for
example. In one further embodiment, the pressurized gas may also be
introduced prior to the solidifying step of the dart head body 23
in a controlled manner, for example, before the complete
solidification of the injected, flowable polymer, to thereby assist
in distributing the flowable polymer within the mold cavity 65
and/or adjusting the thickness of the molded body 23, particularly
the thickness of the head portion 24, for example.
[0060] The present invention is advantageous in that it provides a
hollow and resilient dart head for use in a foam dart. The dart
head is of sufficient resiliency such that, upon impact on a
surface such as a target, the hollow head portion of the dart head
is adapted to resiliently deform, flatten or collapse to thereby
increase the area of contact, i.e. the impact surface with the
target. As a result, the force of impact imposed on the struck
target can be significantly reduced to lower the risk of injuries
and thus to enhance safety of the game. The hollow stem portion of
the dart head also allows adjustment of the dart weight by
receiving a weight carrying insert, which facilitates customization
of flight performance of the resulting toy dart as well as possible
control of the rate of deformation of the hollow head portion
during an impact on a target. The present invention also provides a
relatively quick and easy manufacturing process to integrally mold
the hollow dart head, with the molded material being resilient
enough to allow the integrally formed dart head to be easily
released from the molding equipment by, for example, a simple two
steps, mechanically pushing and/or pulling process, or a
pressurized air assisted detaching process. The processes are
beneficial in ways that they negate the secondary, manual
releasing, detaching or degating step of the molded dart head,
which significantly streamline the manufacturing process.
[0061] The present description illustrates the principles of the
present invention. It will thus be appreciated that those skilled
in the art will be able to devise various arrangements that,
although not explicitly described or shown herein, embody the
principles of the invention and are included within its spirit and
scope.
[0062] Moreover, all statements herein reciting principles,
aspects, and embodiments of the invention, as well as specific
examples thereof, are intended to encompass both structural and
functional equivalents thereof. Additionally, it is intended that
such equivalents include both currently known equivalents as well
as equivalents developed in the future, i.e., any elements
developed that perform the same function, regardless of
structure.
[0063] While the invention has been illustrated and described in
detail in the drawings and foregoing description, the same is to be
considered as illustrative and not restrictive in character, it
being understood that only exemplary embodiments have been shown
and described and do not limit the scope of the invention in any
manner. It can be appreciated that any of the features described
herein may be used with any embodiment. The illustrative
embodiments are not exclusive of each other or of other embodiments
not recited herein. Accordingly, the invention also provides
embodiments that comprise combinations of one or more of the
illustrative embodiments described above. Modifications and
variations of the invention as herein set forth can be made without
departing from the spirit and scope thereof, and, therefore, only
such limitations should be imposed as are indicated by the appended
claims.
[0064] In the claims hereof, any element expressed as a means for
performing a specified function is intended to encompass any way of
performing that function. The invention as defined by such claims
resides in the fact that the functionalities provided by the
various recited means are combined and brought together in the
manner which the claims call for. It is thus regarded that any
means that can provide those functionalities are equivalent to
those shown herein.
[0065] In the claims which follow and in the preceding description
of the invention, except where the context requires otherwise due
to express language or necessary implication, the word "comprise"
or variations such as "comprises" or "comprising" is used in an
inclusive sense, i.e. to specify the presence of the stated
features but not to preclude the presence or addition of further
features in various embodiments of the invention.
[0066] It is to be understood that, if any prior art is referred to
herein, such prior art does not constitute an admission that the
prior art forms a part of the common general knowledge in the
art.
* * * * *