US4457511A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Plastic bowling pin and method of making the same
Assignee: Individual
•
Filing: 1982-03-15
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Granted: 1984-07-03
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Expires: 2002-03-15
Abstract
Abstract An injection molded bowling pin with a core of thermoplastic plus a blowing agent and a solid skin of thermoplastic per se injected into the mold at one and the same time. The bowling pin is molded by a process wherein a foam material for forming the core is surrounded by and in contact with a nonfoam material and both materials are simultaneously injected into a mold cavity having the shape of a bowling pin. The skin and core may be of the same or of different thermoplastic. The bowling pin is a unitary structure of superior strength and finish with the foamed core and solid skin fused together.
Inventors
- 👤 William Witkowski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:35
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/02; B29C44/04; B29C44/0461; A; A63; A63D; A63D9/00; B29C45/00; B29C45/16; B29C45/164; B29C45/1642; Y; Y10; Y10S; Y10S264/00; Y10S264/83
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
148 words
A bowling pin having a central core of a mixture of thermoplastic and a foaming agent surrounded by a hollow discrete skin of thermoplastic per se, and having been made by a process wherein both the core mixture and the thermoplastic per se are coinjected while in conforming contact and while the thermoplastics are in a heated and viscous state and coinjected under pressure in a mold cavity having the shape of a bowling pin, the outer surface of the thermoplastic per se being in contact with the mold cavity and the outer surface of the mixture being in contact with the inner surface of the thermoplastic per se, the thermoplastic per se and mixture being distinct materials which are united at the surfaces which are pressured into contact while the thermoplastics are in the viscous state and which become joined into a unitary rigid body upon cooling.
Claim 2
Dependent Claim
148 words
A bowling pin having a central core of a mixture of thermoplastic and a foaming agent surrounded by a hollow discrete skin of thermoplastic per se, and having been made by a process wherein both the core mixture and the thermoplastic per se are coinjected while in conforming contact and while the thermoplastics are in a heated and viscous state and coinjected under pressure in a mold cavity having the shape of a bowling pin, the outer surface of the thermoplastic per se being in contact with the mold cavity and the outer surface of the mixture being in contact with the inner surface of the thermoplastic per se, the thermoplastic per se and mixture being distinct materials which are united at the surfaces which are pressured into contact while the thermoplastics are in the viscous state and which become joined into a unitary rigid body upon cooling.
Claim 3
Dependent Claim
28 words
The structure of claim 1 in which the pin is initially cooled in the mold until the skin is dimensionally stable and then further cooled outside the mold.
Claim 4
Dependent Claim
20 words
The structure of claim 1 in which the skin covers the sides of the pin and at least one end.
Claim 5
Dependent Claim
21 words
The bowling pin of claim 1 in which the thermoplastic in the skin is different from the thermoplastic in the core.
Claim 6
Dependent Claim
19 words
The bowling pin of claim 1 in which the thermoplastic of the skin and of the core is polypropylene.
Claim 7
Dependent Claim
34 words
The pin of claim 1 in which the base of the pin has an upwardly extending reentrant opening surrounded by said skin of thermoplastic per se and an annular section of said foamed thermoplastic.
Claim 8
Dependent Claim
26 words
The structure of claim 1 in which the pin has a small diameter neck at its upper end and the skin is thicker at the neck.
Claim 9
Dependent Claim
32 words
The structure of claim 1 in which the pin has a small diameter neck at its upper end and the upper end of the neck is formed by injection of thermoplastic alone.
Claim 10
Dependent Claim
37 words
The structure of claim 1 in which the pin has a small diameter neck at its upper end and the skin of thermoplastic per se is thicker at the neck than on the remainder of the pin.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-07-03 | 1988-01-02 | 1988-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-03 | 1992-01-02 | 1992-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-03 | 1996-01-02 | 1996-07-03 | $7700.00 | Window Closed / Lapsed |