US3801102A

US3801102A - Safety dart and method for manufacturing the same

Info

Publication number: US3801102A
Application number: US00216218A
Authority: US
Inventors: R Lohr; J Quigley
Original assignee: Louis Marx and Co Inc
Current assignee: Marx L & Co Inc us; Louis Marx and Co Inc
Priority date: 1972-01-07
Filing date: 1972-01-07
Publication date: 1974-04-02
Anticipated expiration: 1991-04-02

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.

Description

United States Patent [191 Lohr et al.

451 Apr. 2, 1974 SAFETY DART AND METHOD FOR MANUFACTURING THE SAME [75] Inventors: Raymond J. Lohr, Erie; John B.

Quigley, Girard, both of Pa.

[73] Assignee: Louis Marx & Co., Inc., Stamford,

Conn.

[22] Filed: Jan. 7, 1972 [21] Appl. No.: 216,218

[56] References Cited UNITED STATES PATENTS 3,124,119 3/1964 Ayala 273/1065 A 2,392,091 l/l946 Kieft 248/206 R 398,679 2/1889 White..... 248/206 R 2,144,159 1/1939 Kieft 248/206 R 3,411,782 11/1968 Wood 273/DIG. 25 1,478,279 12/1923 Henne 248/206 R X Primary Examiner-Anton O. Oechsle Assistant Examiner-Paul E. Shapiro Attorney, Agent, or Firm-Blum, Moscovitz, Friedman & Kaplan [57] 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.

2 Claims, 3 Drawing Figures SAFETY DART AND METHOD FOR MANUFACTURING THE SAME 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 freeend 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 fiat 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 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 materiai 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 surfacebonding 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.

What is claimed is:

l. 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.

Claims

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.