US 3301560 A
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Description (OCR text may contain errors)
, 1967 F, E. SATCHELL ETAL 3,3l550 BOWLING PIN WITH SOUND CONTROLLING MEANS 2 Sheets-Sheet l Jan. 31
original Filed Nov. 20, 1959 Olli,
1967 F. E. sATcHELL ETAL 3,30550 BOWLING PVIN WTH SOUND CONTROLLING MEANS 2 Sheets-Sheet 2 INVENTORS.
www I MMWW ff am Jan. 3l,
Original Filed Nov. 2O
United States Patent p 3,301,560 BOWLING PIN WITDIESISUND CONTROLLING Fred E. Satchell, Muskegon, Mich., `andWilliam L. Jolitz,
l Oaks, Pa., assignors to Brunswick Corporation, a corporation of Delaware Sv Original application Nov. 20, 1959, Ser. No. 854,515, now Patent No. 3,138,380;` dated June 23, 1964. Divided and this application Ochs, `1963, Ser.,No. 314,652
- f 4 Claims..V (Cl. 273-82) This application isA a division of y our co-pending application, seria No.` 854,515, filed November 20, 1959,
'characteristics Aas well as-to closely approach a'conventional wood bowling pin inaction and sound.
An object of'this invention is to provide a new and Iimproved bowling pin having 'a lightweight metal hollow core with sound controlling means internally of the core, and` an exteriorcoating on said core resulting in a pin having the" action and sound generally; similar to that of the wood bowlingpin `nowy commonly Yused in bowling i Another object of the invention is to provide a bowling pin having a lightweight metal hollow core and an exterior coating in which sound controlling means are disposed internally of the core and embody :structural additions to the interior of the'core wa-ll which tend to quick-ly dissipate certain objectionable vibrations of the pin core. j
Further objects and advantages will becomeapparent 'from'the following detailed description taken in connection with theaccompanying drawings in which:
. FIG. 1 is a vertical section of a first embodiment of a bowling pin;
FIG. 2 is a` plan section of the pin shown in FIG. 1 and taken generally along the line 2-2 in FIG. l; FIG.` 3 isa vertical section of a Vsecondembodiment of a bow-ling pin; A i v FIG. 4 is a plan section of the bowling pin shown in FIG. 3 and taken generally along theI line 4-4 in FIG. 3;
.i FIG. 5 is a vertical' section of a third embodiment of a bowlingpin; Y
FIG. 6 isa vertical section of a fourth embodiment of a bowling pin; I
FIG. 7 is a'plansectionof the bowling pin shown in FIG. 6 and taken generallyalong theline `7-7 in FIG.
a bowling pin; and` i FIG. 9 is a plan sectionofthe bowling pin'shown in FIG. `8 taken generally along the line 9 9 in FIG. 8.
l`While this invention lis susceptible of embodiment in i 'many different flor-ms, there are shown in` the drawings y and willherein Abedescribed in detail several embodiyrn'entsmof the invention ,with the understanding that the .K presentdisclosure is `to vbe considered as an exemplifcation of the principles of the invention andis not intended `,to lirnit theinvention to the embodiments illustrated. The scope of the invention willy be pointed out in the appended claims. f
FIG. 8 is a vertical'section of a fth embodimentof i lCC A bowling pin, as shown in FIG. l, generally comprises a hollow core 1 having a resilient coating 2 secured to theexterior thereof with an adhesive 3. The hollow core 1 has sound controlling means 4 including foam material 20 disposed within the cavity within the hollow core 1. In order to complete the pin, a pin bottom 5 is secured to Vthebase of the hollow core 1. A tenpin is disclosed herein, but the invention disclosed herein is applicable to other bowling Ipins such as duckpins; candlepins and Canadian iivepins.
The durability of the bowling pin is fundamentally determined by the core 1, which is composed of strong, lightweight metal alloy, primarily magnesium, with the durability increased by 4the resilient coating 2.` In addition to the magnesium, other metals are present in the alloy and include small amounts of aluminum and zinc.
In the embodiment illustrated, the core 1 has a core lwall 10 with an exterior shape closely corresponding to that of a bowling pin, but of a lesser size than aV pin in order! to permit additions yto the exterior thereof to obtan the final bowling pin size. In Vtheembodiment of a bowling tenpin, as shown in FIG. l, thickness of the core wall 10 varies between a head end 11 of t-he core and a base 12.
The present rules of `the American Bowling'Congress provide that a bowling pin must weigh not less than 2 lbs; 14 ozs., nor more than 3 lbs. l0 ozs. In an actual embodiment of apin having a total weight of 3 lbs. 4 ozs., the core 1 has aweight of approximately 2 lbs.r3 ozs. Thus, the core weight, with some variation therein, would consitute 60 to 90 percent of the total pin weight within the ABC limits. In an actual embodiment shown in FIG. l, which has been found to provide a satisfactory core, the head end 11 has a core wall thickness of .140 inch, while the neck area 13 has a core Wall thickness of .175 inch with thecore wall at the belly area A14 ofthe core havinga thickness of .375 inch and the wall gradually increasing in thickness from the neck area 13. t`o the belly area 14. The core wall then decreases in thickness from the belly area to the b ase with a core wal-l thickness of .185 inch generally near the base, and the base itself havinga thickness of .35 inch. The thickness of the core |base 12 is suflicient to prevent crack-ing across the base. I
Iniorder to increase the cores durability, a large `rib 15 is positioned on the interior of the core wall 10-in `the belly area 14 and preferably cast` integrally therewith `to rigidize the core and decrease the possibility of core denting in the thinner areas adjacent the belly area 14 by in effect decreasing t-he span across which the impact can work upon the core wall,
A metal core is louder when impacted than the conventional wood pin. In order to have the final pin with a metal core approach the sound characteristics of a wood pin, the core has the coating 2 and sound controlling means 4 associated therewith.
There are two modes of vibration of the pin core 1 which may be taken into account in producing the proper sound of the pin upon impact. One of these modes of vibration is the flexural mode, which is the vibration produced along the longitudinal axis of the core extending from the head 11 to the base 12 thereof with the head` 11 and base 12 moving in a common phase and the center ofthe pin moving in opposite phase. The headl11 and neck part 13 of the core are largely responsible forthis vibration.` The other vibration is the bell mode, which is va vibration in a plane parallel to the base 12 of the core across the belly area 14 of the core.
other to produce the bell mode sound. Other vibra-tions occur at different angles to the aforementioned ellipses but are not as important to the basic sound audible to a person.
Each of the vibrations may be considered from the standpoint of the resonant frequency determining the pitch of the resultant sound as well as the Q factor, with the Q factor being the ratio of the energy stored per cycle to the energy dissipated per cycle. A rapid decay rate results in a low Q factor, and a sound with a high Q factor lasts longer than a sound with a low Q factor.
In order for the bowling pin to have a sound corresponding to that of a wood pin, as stated previously, the hollow core 1 and its vibra-tions upon impact are modified by the pin coating 2, and sound controlling means within the core.
Generally, the bell mode of vibration must be minimized and the flexural mode must cont-rol the sound of the pin because it has been found that with a wooden pin, the bell mode of vibration is so mall as to be negligible. The minimization of the bell mode of vibration by the sound controlling means thus results in a pin having a sound determined primarily by the flexural mode and closely approximating that of a wood pin. It has been found that the Q ratio of flexural mode to bell mode should be at least three with the bell mode minimized.
The coating 2 also has an effect on the two modes of vibration, and it has been found that a substantially thick coating causes the pin to have a sound more nearly approaching that of a wood pin than a relatively thin coating. Localized thickening of the coating in the belly area by means such `as a rubber band functions to reduce the impact noise of the pin.
The coating 2 has the basic function of cushioning the oore 1 and also contributes to the factors of sound, las mentioned above, and action of the pin. This coating, in the embodiment shown in the drawings, has athickness of one-eighth inch at the belly area of the pin, and provides approximately twelve ounces of weight to the iinished pin. The coating results in a nal external pin contour meeting ABC requirements. The coating may be plastisol or nylon material, and preferably is an ethocel gel lacquer coating. Prior to the coating, the surface of the core is treated with cleaning solutions, including a solution of sodium dichromate and nitric acid. After the core surface is dry, an adhesive is applied thereto. As an example, the adhesive may be a synthetic rubber based mixture. After adhesive application, an active ethyl cellulose is applied and the ethyl cellulose gel lacquer is applied as a nal step by a series of dip coatings.
The coating also tends to overcome the high moment of inertia of the pin about the vertical axis thereof since the relatively thick coating, which is somewhat resilient in character, will be deformed upon impact by either a ball or a pin t-o provide a greater contact area and thus result in more rotation being given to the pin on an off center impact.
It has been found that the coating also functions to reduce the rebound characteristic of the pin to that encountered with `a wood pin when the pin of this invention is impacted by a medium speed ball.
The pin bottom 5 is to provide a durable and nondestructive base to the pin. Its high physical requirements result from the fact that a pin struck by a ball illes through the air with the base of the pin leading the way. Hence, many secondary impacts of the pin are pin bottom impacts to other objects such as the kick-backs or other pins. The bottom is made from a material of high physical properties such as nylon to withstand the abuse encountered. Another material that i-s satisfactory is a polycarbonate. The pin bottom 5 is threadably attached to the base 12 of the core, as indicated at 25.
The composite pin has a center of gravity generally the same as for a wood pin with resultant similar actions upon impact.
In the embodiments disclosed, sound controlling means are provided which decrease the bell Q factor by breaking up the symmetry of vibration operating principally in four quadrants -to quickly dissipate the sound and also make it harder for the mode to operate by a rigidizing effect on the core.
In FIGS. 1 and 2, the hollow core 1 has a flexible foam 20 within the core cavity and a slug 27 bonded against the core wall interior. The slug 27 extends both above and below the strengthening rib 15 of the core and, as shown in FIG. 2, spans a fraction of the interior periphery of the core 1 and is of a material consisting primarily of synthetic resins having terminal epoxide groups.
In the embodiment of FIGS. 3 and 4, the sound controlling means comprises a centered web bracing structure including a center plug 30 centrally disposed on the longitudinal axis of the core 1 and having three equally spaced apart radially extending ribs 31 which merge and are formed integrally with the interior of the core wall 1.
In the embodiment of FIG. 5, the core 1 has a diagonal inclined rib 32 of generally round cross section spanning opposed parts of the core wall interior to dampen vibrations in the bell mode. The diagonal rib 32 as shown merges into the core wall 1 and is formed integrally therewith.
In the embodiment of FIGS. 6 and 7, a structure is shown in which the core is permitted to vibrate in the bell mode without any special rigidifying effect, but the vibration is quickly absorbed. In this construction, a center pin 33 extends inwardly from the core wall 1 and terminates at the longitudinal axis of the pin. This pin 33 is located at the belly area of the pin and extends inwardly from the strengthening rib 15.
In the embodiment of FIGS. 8 and 9, a construction is shown which breaks up the symmetry of bell mode vibration to lessen the effect thereof. This is accomplished by having the strengthening rib off center, which breaks up the symmetry of the core. The rib has its thickest part on the order of more than twice as thick as the thinnest. This off-centering of the core also creates vertical imbalance of the pin contributing to the action of the pin upon impact.
Additional durability is provided in the pin by prolonged aging of the core 1 at normal room temperatures. Further durability is obtained by cold working of -the core and particularly the neck area 13 to place the outermost part of the core wall in compression to lower the stress in the metal during exure upon pin impacts. This, as an example, can be obtained by shot peening in which the neck area 13 is impacted by round metallic shot impinging at a high velocity.
1. A bowling pin adapted to provide a sound substantially similar to a conventional maple wood pin on impact with a bowling ball or another pin comprising: a hollow metallic core, said core having the elongated shape of a bowling pin with a neck-head portion, a belly portion and a base portion, said core further having sound determining modes of vibration, one being a bell mode caused principally by vibration of the belly of said pin and the other being a flexural mode caused principally by the neck-head and base moving in -a common phase and the belly moving in opposite phase, said bell mode being undesirable in that audibly it sounds harsh and unwooden while said flexural mode is desirable in that it sounds not unlike a maple wood pin which has a similar flexural mode; a mass positioned eccentrically within said hollow core in lthe belly area adapted to break up the symmetry of vibration of said bell mode to quickly dissipate the sound thereof without adversely affecting the desirable vibration of said exural mode; said belly area being devoid of other masses tending to compensate for the eccentrically positioned mass; and a lresilient plastic coating encasing said core.
2. The bowling pin of claim 1 wherein said mass comprises a pin on the wall of said core extending generally normal thereto and terminating near the longitudinal center line of the core.
3. The bowling pin of claim 1 wherein said mass comprises a continuous rib on the core Wall interior in the belly area and disposed off center with respect to the 1ongitudinal axis of the pin by varying in radial thickness with the thickest part being on the order of more than twice as thick as the thinnest.
4. The bowling pin of claim 1 wherein said mass cornprises a slug of synthetic resinous material disposed prin- Y cipally in the belly of the core and spanning a fraction of the interior circumferential periphery thereof.
References Cited by the Examiner UNITED STATES PATENTS 1,131,090 3/1915 Seidel et al. ,273-82 2,166,950 7/ 1939 German et a1. 273-82 3,044,777 7/ 1962 Friedman 273-82 3,048,400 8/ 1962 Friedman 273-82 DELBERT B. LOWE, Primary Examiner.