U.S. patent number 3,801,102 [Application Number 05/216,218] was granted by the patent office on 1974-04-02 for safety dart and method for manufacturing the same.
This patent grant is currently assigned to Louis Marx & Co., Inc.. Invention is credited to Raymond J. Lohr, John B. Quigley.
United States Patent |
3,801,102 |
Lohr , et al. |
April 2, 1974 |
SAFETY DART AND METHOD FOR MANUFACTURING THE SAME
Abstract
A safety dart and method for manufacturing the same. The safety
dart includes an elongated shaft having an elongated free end
portion terminating in an end surface of the shaft and formed with
a transverse opening spaced from the latter end surface. A suction
cup is fixed to the shaft at the free end portion of the latter,
surrounding this free end portion and having part of the material
of the suction cup itself extending through and filling the
transverse opening to achieve a strong mechanical connection
between the suction cup and the shaft. Preferably the materials
used for the suction cup and shaft are such that there will be a
surface bond also between the suction cup and the shaft. The shaft
is first molded and then the shaft is placed in a suction cup mold
with the free end portion of the shaft together with the transverse
opening in this free end portion situated in the hollow interior of
the suction-cup mold. Then the suction cup itself is molded around
this free end portion of the shaft so that the material of the
suction cup will flow through and fill the transverse opening of
the shaft. The shaft is preferably made of a solid body of high
impact styrene and the suction cup is preferably made of resilient
yieldable plastic which has a styrene butadiene polymer base.
Inventors: |
Lohr; Raymond J. (Erie, PA),
Quigley; John B. (Girard, PA) |
Assignee: |
Louis Marx & Co., Inc.
(Stamford, CT)
|
Family
ID: |
22806227 |
Appl.
No.: |
05/216,218 |
Filed: |
January 7, 1972 |
Current U.S.
Class: |
473/572; 29/450;
29/451 |
Current CPC
Class: |
F42B
6/003 (20130101); Y10T 29/4987 (20150115); Y10T
29/49872 (20150115) |
Current International
Class: |
F42B
6/00 (20060101); A63b 065/02 () |
Field of
Search: |
;273/16.5A,DIG.25
;248/26R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Oechsle; Anton O.
Assistant Examiner: Shapiro; Paul E.
Attorney, Agent or Firm: Blum, Moscovitz, Friedman &
Kaplan
Claims
What is claimed is:
1. A safety dart comprising a shaft having an elongated free end
portion terminating in an end surface situated at one end of said
shaft, said elongated free end portion being formed with an opening
passing transversely through said elongated free end portion and
spaced from said end surface, a suction cup fixed to said shaft at
said free end portion thereof, said suction cup having a cup
portion situated beyond said end surface and an elongated rear neck
portion surrounding said elongated free end portion of said shaft
with said elongated free end portion of said shaft extending into
said rear elongated neck portion of said suction cup, and means
fixed to said neck portion of said suction cup and extending
through said opening for mechanically fixing said suction cup to
said shaft, said means filling said transverse opening, and said
means being integral with and made of the same material as said
suction cup, the material of said suction cup being bonded to the
surface of said shaft for providing a connection with the latter in
addition to the connection provided by said means, said shaft being
made of a solid body of high impact styrene and said suction cup
being made of a resilient yieldable plastic which has a styrene
butadiene polymer base.
2. A safety dart comprising a shaft having an elongated free end
portion terminating in an end surface situated at one end of said
shaft, said elongated free end portion being formed with an opening
passing transversely through said elongated free end portion and
spaced from said end surface, said suction cup fixed to said shaft
at said free end portion thereof, said suction cup having a cup
portion situated beyond said end surface and an elongated rear neck
portion surrounding said elongated free end portion of said shaft
with said elongated free end portion of said shaft extending into
said rear elongated neck portion of said suction cup, and means
fixed to said neck portion of said suction cup and extending
through said opening for mechanically fixing said suction cup to
said shaft, said means filling said transverse opening, and said
means being integral with and made of the same material as said
suction cup, the material of said suction cup being bonded to the
surface of said shaft for providing a connection with the latter in
addition to the connection provided by said means, said shaft being
made of a solid body of high impact plastic and said suction cup
being made of a resilient yieldable plastic, and the latter two
plastics having an affinity for each other providing the direct
bonding of the plastics to each other without any additional
material situated between the bonded plastics.
Description
BACKGROUND OF THE INVENTION
The present invention relates to darts.
In particular, the present invention relates to safety darts of the
type which have at one end a suction cup rather than a pointed
metal tip.
While safety darts of the above general type are already known, the
conventional darts of this type suffer from serious drawbacks. The
most serious drawback resides in the fact that the suction cup does
not remain permanently fixed with the shaft. Initially when such a
safety dart is manufactured and sold there may be a fairly secure
connection between the suction cup and the shaft of the safety
dart. However, before long the security of the connection between
the suction cup and the shaft diminishes and the suction cup
becomes separated from the shaft. The result is not only that a
considerable inconvenience is involved in continuously replacing
the suction cup on the shaft while continuing to attempt to use the
dart, but in addition the exposed free end of the shaft which
initially was connected with the dart represents an element of
danger particularly to a child, and because of the inconvenience in
using a dart when the suction cup is easily separated from the
shaft such an item is soon discarded since it becomes practically
useless. The primary reason for these problems resides in the fact
that the suction cup is conventionally provided only with an
opening for receiving the free end of the shaft, and the connection
is made primarily through chemical means such as by using a glue or
by providing a suitable solvent for achieving a bond between the
material of the suction cup and the shaft. However, experience has
shown that after such an item is used for a while either the bond
breaks down due to drying or this latter factor together with the
impact forces to which the dart is subjected results in a condition
where the suction cup is readily separated from the shaft. One of
the primary considerations in this connection is the fact that a
child will normally tend to pull a toy apart. Thus, even if the
suction cup does adhere to some degree to the shaft, if the degree
of adherence is not great enough a child will simply pull the cup
off the shaft rendering the dart useless.
SUMMARY OF THE INVENTION
It is accordingly a primary object of the present invention to
provide a safety dart which will avoid the above drawbacks.
Thus, it is an object of the present invention to provide a safety
dart which has an extremely secure connection between the suction
cup and the shaft, making it practically impossible to separate the
suction cup from the shaft even after long periods of use of the
dart.
In addition it is an object of the present invention to provide a
method for manufacturing a safety dart in such a way that it
becomes possible to achieve the above objects.
In addition it is an object of the present invention to provide a
safety dart and method for manufacturing the same which will retain
the advantages of the bonded type of connection already known while
adding to this latter type of connection the security achieved by
way of a mechanical connection of the components.
According to the invention the safety dart has an elongated shaft
provided with a free end portion terminating in an end surface of
the shaft and formed with a transverse opening spaced from the
latter end surface. A suction cup is carried by the free end
portion of the shaft with this free end portion extending into a
neck of the suction cup which surrounds the free end portion of the
shaft. A means which is fixed to the suction cup itself extends
through the transverse opening in order to provide a mechanical
connection of the suction cup to the shaft.
With the method of the invention the above shaft is first molded,
and then the latter shaft is placed with its free end portion,
including the transverse opening therein, in the hollow interior of
a suction-cup mold. Then when the suction cup is molded the
material thereof will flow into and fill the transverse opening, so
that in this way a mechanical connection of the suction cup to the
shaft is achieved.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is illustrated by way of example in the accompanying
drawings which form part of this application and in which:
FIG. 1 is a perspective illustration of a safety dart shaft
according to the invention;
FIG. 2 is a perspective illustration of the shaft of FIG. 1
assembled with a suction cup; and
FIG. 3 is a sectional plan view taken along line 3--3 of FIG. 2 in
the direction of the arrows and showing details of the structure
and method of the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to the drawings, there is shown in FIG. 1 a shaft 10
of a safety dart of the invention. This shaft 10 is formed of an
elongated solid body 12 which is generally of a cylindrical
configuration. This body has a rear enlarged flat end 14, in the
form of an end flange, providing a relatively large flat rear
surface which is safe for a child.
Opposite to the rear end 14, the shaft 12 has an elongated free end
portion 16 terminating in an end surface 18 of the shaft. This
elongated free end portion 16 extends forwardly from a flange 20.
The shaft 12 fixedly carries elongated guide fins 22 which extend
axially along the shaft rearwardly from the flange 20.
According to one of the features of the invention the free end
portion 16 of the shaft 12 is formed with a transverse opening 24
passing therethrough and spaced from the end surface 18, as well as
from the flange 20. It will be noted that this transverse opening
24 is of a generally rectangular cross section.
The entire shaft 10 shown in FIG. 1 and described above is molded
in one piece so that it forms a unitary solid body. Thus, the mold
in which the shaft 12 is molded will have a transverse core in
order to form the opening 24 in the shaft 10. Preferably this shaft
10 is made of a hard full high impact styrene. The molding of this
shaft 10 forms the first step in the method of the invention for
manufacturing the shaft 10 of the present invention.
The completed saftey dart of the invention is shown in FIG. 2. Thus
FIG. 2 shows a suction cup 26 fixed to the shaft 10. This suction
cup 26 has a front cup portion 28 and a rear neck portion 30 which
extends rearwardly from the cup portion 28 all the way up to the
flange 20 which is engaged by the neck portion 30 of the suction
cup 26. It will be noted that the exterior diameter of the neck
portion 30 of the suction cup 26 is equal to the exterior diameter
of the flange 20 and that the neck portion 30 is cylindrical so
that it forms a continuation of the outer surface of the flange 20.
As is particularly apparent from FIG. 3, the dart of the invention
is provided with a means 32 for mechanically fixing the suction cup
26 to the shaft 10. This mechanical means 32 is fixed directly with
the suction cup and extends through the transverse opening 24. As
is illustrated in FIG. 3, the mechanical fixing means 32 is
integral with the suction cup 26, forming one body of material
therewith. Thus, part of the material of the suction cup 26 itself
extends completely through and fills the opening 24.
This mechanical fixing means 32 is preferably achieved, according
to the method of the invention, by introducing the free end portion
16 of the shaft 10 into a suction-cup mold in which the suction cup
26 is molded after the shaft 10 is molded. When placed within the
suction cup mold, the hollow interior of the suction cup mold is
closed at least in part by the flange 20 while the elongated free
end portion 16 and the opening 24 are situated freely within the
hollow interior of the suctioncup mold where the material
introduced into the mold form the suction cup 26. Thus, this free
end portion 16 of the shaft 10 may be situated in the
above-described manner in the hollow interior of an injection mold
which forms the suction-cup mold and in which the suction cup 26 is
molded around the elongated free end portion 16 of the shaft 10.
The material which is introduced into the hollow interior of the
suction-cup mold not only surrounds the free end portion 16 of the
shaft 10 but in addition this material flows through and fills the
opening 24 so as to achieve in this way the fixing means 32.
A safety dart 10 having the above-described structure and
manufactured according to the above method will connect the suction
cup to the shaft mechanically, by reason of the mechanical fixing
achieved with the means 32, in such a way that the suction cup
cannot be pulled off from the shaft.
However, in addition to this mechanical fixing a further security
is the connection is achieved by surface-bonding the suction cup to
the shaft. As was indicated above the solid shaft 10 is preferably
made of high impact styrene. The resilient springy yieldable
material of the suction cup is preferably composed of a plastic
which has a styrene butadiene polymer base, so that when the molten
plastic of the softer suction cup material is introduced into the
mold and flows around the free end portion 16 of the shaft 10 as
well as through the opening 24, there is a great affinity between
the material of the shaft and the material of the suction cup with
the latter bonding itself to the exterior surface of the shaft to
achieve not only the mechanical connection but also the bonded
connection. Thus, as a result of this bond the suction cup is fixed
with the shaft not only by the mechanical connection achieved with
the means 32 but also by direct bonding of the material of the
suction cup to such surfaces as the end surface 18, the forwardly
directed surface of the flange 20, and the exterior surface of the
elongated free end portion 16 beyond the opening 24.
In this way an exceedingly secure connection between the suction
cup and shaft is achieved with the safety dart of the invention.
For all practically purposes, the suction cup and shaft of the
safety dart of the invention may be considered as the equivalent of
a single body of material. However, while the equivalent of a
single unitary body of material is achieved, the suction cup still
maintains its yieldable resilient qualities while the shaft 10 is
still substantially rigid.
* * * * *