US3024819A

US3024819A - Method of and apparatus for compressing and densifying a bowling pin impact zone

Info

Publication number: US3024819A
Application number: US18217A
Authority: US
Inventors: Cornelius D Dosker
Original assignee: Gamble Brothers Inc
Current assignee: Gamble Brothers Inc
Priority date: 1960-03-22
Filing date: 1960-03-22
Publication date: 1962-03-13
Anticipated expiration: 1979-03-13

Description

D. METHOD OF AND APEAR c. DOSKER 3,024,819

ATUS FOR COMPRESSING AND A BOWLING PIN IMPACT ZONE March 13, 1962 DENSIFYING 5 Sheets-Sheet 1 Filed March 22, 1960 INYENTOR. coRNELu/s o. DOSKER ATTORNEY March 13, 1962 c. D. DOSKER 3,024,319

METHOD OF AND APPARATUS FOR COMPRESSING AND DENSIFYING A BOWLING PIN IMPACT ZONE Filed March 22, 1960 5 Sheets-Sheet 2 FIG. ll

INVENTOR.

CORN ELIUS D. DOSKER ATTORNEY March 13, 1962 c. D. DOSKER 3,024,319

METHOD 0 ND APPARATUS FOR COMPRESSING AND ENSI NG A BOWLING PIN IMPACT Z0 D Filed March 22, 1960 Sheets-Sheet 3 INVENTOR. CORNELIUS D. DOSKER OMZMM ATTORNEY tuclry Filed Mar. 22, 1960, Ser. No. 18,217 12 Claims. (Cl. 144-320) This invention relates to methods for compressing and densifying the ball-impact belly of a bowling pin. The impact zone extends horizontally around and vertically across the belly of the pin. It may be viewed as being centered more or less on either or both the pins equator and its ball-line. The equator is a surface line which encircles the pin in the horizontal plane of its maximum belly diameter. The ball-line is a surface line along which a bowling ball normally strikes an upright pin and, it encircles the pin on a horizontal plane located slightly below the equator. For the sake of clarity, we shall hereinafter view the impact zone as being centered on the equator. This application is a continuation-in-part of my copending US. application, Serial No. 733,862, filed May 8, 1958, and formally abandoned.

It is old to compress and density the impact zone of a bowling pin to improve its wearing characteristics. The prior art does this by forcing an oversize pin axially through a heated and tapered sleeve as shown in the U8. Patent, No. 2,652,081, to Curtis. This method compresses the equator of the pin, but does not compress it much above or below this line. The compressed area of the pin is thus limited to a rather narrow band encircling the belly at its equator with definite boundary lines between the compressed and uncompressed areas of the pin. I have found that the wearing characteristics of the pin may be very substantially improved by compressing it substantially above and below the equator as well as along its equator, and that this can be accomplished without necessarily creating any definite boundary lines between the compressed and uncompressed areas of the pin.

The principal object of this invention is to provide a method for compressing the impact zone or belly of a bowling pin substantially above and below its equator as well as along its ball-line.

Another object of this invention is to provide a method of compressing the impact zone of a bowling pin without producing definite demarcation or boundary lines be. tween the compressed and uncompressed areas of the pin.

These objects are attained by positioning an oversized bowling pin between three circumferentially spaced concave rollers rotating on axes parallel to the longitudinal axis of the pin, the rollers having a concave curvature of a slightly less degree than the longitudinal convex curvature of the pin belly, moving the rollers together to compress the pin belly and simultaneously turning the pin between the rollers. These rollers may be either heated or unheated, although preferably they are unheated. The rollers are forced together in a manner such; as to institute compression at and across said equator but only partially across said impact zone and thereafter progressively increase the degree of compression at said equatorup to a predetermined amount and contemporaneously widen the band of compression across said zone in a progressive manner proceeding in both directions vertically away from said equator while maintaining a compressive pressure gradient which also progressively decreases in both directions proceeding vertically away from said equator. The compression operation is continued until the impact zone or belly of the pin is compressed substantially to its final size along its equator. This operation etfectsa maximum degree of compression at said equator and a United States Patent progressively decreasing degree of compression proceeding in both vertical directions away from the equator to the upper and lower edges of the rollers where the compression is substantially zero. This provides a compressed impact zone which progressively blends in with the uncompressed areas of the pin, thus eliminating any definite demarcation lines between the compressed and uncompressed areas of the pin and any abrupt changes of the degree or amount of compression or densification of the wood proceeding vertically across the impact zone. This elimination of definite demarcation lines between the compressed and uncompressed areas of the pin progressively ioins or blends the high stressed areas in the pin around its ball-linc with the low stressed areas (the: uncompressed areas) of the pin, instead of joining them abruptly, and is one reason why a bowling pin treated by my method possesses improved wearing characteristics as compared to those pins treated by the prior art methods.

A bowling pin may be compressed without applying a suitable resin to the pin belly, or, preferably, the impact belly of the pin is coated with a suitable resin prior to its compression to set the wood fibers after compression. The use of a resin wets the wood fibers and reduces their tendency to separate during compression, in addition to aiding in holding the fibers in their final compressed state.

After the bowling pins belly is compressed, the pin is turned to its final size, where necessary, or it may be only sanded to smooth its surface. During this step, little or no wood is removed-from the equator of the pin belly as this was compressed to substantially final size during the compression step.

The invention is illustrated in the accompanying drawings wherein:

FIG. '1 is an elevational view of an oversize bowling pin having its final size or profile indicated in dotted lines;

FIG. 2 is an elevational view illustrating the oversize bowling pin having its lower surfaces sealed with wax;

FIG. 3 is an elevational view of the bowling pin of FIG. 2, having its belly surfaces coated with a suitable resin;

FIG. 4 is an elevational view of the bowling pin of FIG. 3 having its belly initially engaged with a compression roll;

FIG. 5 is an elevational view of the bowling pin of FIG. 4 in the final states of being compressed against a compression roll;

FIG; 6 is a perspective view illustrating the three circumferentially spaced compression rollers used to compress the bowling pin;

FIG. 7 is an elevational view of the compressed bowling pin being turned to final size;

FIG. 8 is a side elevational view of a bowling pin compression machine;

FIG. 9 is a cut-away top plan view of the machine of FIG. 8;

FIG. 10 is a fragmentary bottom plan view of the left end of the compression machine;

FIG. 11 is a fragmentary elevational view of the machine illustrating a bowling pin positioned in the machine;

FIG. 12 is an elevational view of an oversize bowling pin used in amodified method and showing it before having its belly compressed;

FIG. 13 is an elevational view of the bowling pin of FIG. 12 having its belly compressed following the modified method;

FIG. 14 is an enlarged fragmentary vertical section 0 the belly of a bowling pin, lying on its side, before compression by the modified method, With the dotted lines Patented Mar. 13, 1982 METHOD-FIGS. 17

The specific embodiment illustrated in FIGS. 1 to '7 of the novel method of making a compressed belly bowling pin includes five steps. These are: forming an oversize bowling pin; sealing the lower surfaces of the pin; applying resin to the pin belly; compressing the pin belly between concave rollers; and turning the compressed pin to final size.

Oversize Pin The oversize bowling pin 1 of FIG. 1 is similar to conventional bowling pine with the exception that it is about inch oversize, i.e. inch larger than the size desired in its final form. The wood fibers in the pin 1 run vertically between the ends of the pin, the same as in conventional pins. It is conventionally made by turning down a suitable block of maple :wood, which may be a single piece of wood, but preferably is a composite of several pieces bonded together.

The final size or profile of the pin is indicated in FIG. 1 by the dotted lines 2 running parallel to and spaced slightly inward from the solid lines indicating the oversize pins sides. The pin 1 includes three major portions, a head 3, a belly or impact zone 4 and a base 5, the head 3 being that portion located above the horizontal dotted line 6, the belly 4- being between the horizontal dotted lines 6 and 6' and the base 5 being below the horizontal dotted line 6'.

Sealing Lower Surfaces The surfaces of the base 5, below the belly 4 of the oversize pin 1, are sealed with wax or other suitable substance by immersing the base of the pin in a bath 8 of heated sealing wax up to the horizontal dotted line 6, as shown in H6. 2. This treatment seals the wood pores of the base surfaces against the entry of resin during the following resin applying step. Thi is only one of the Ways that the lower surfaces of the pin may be sealed. This step may be omitted when it is not desired to protect the lower surfaces of the pin from the resin during the resin applying step.

Applying Resin The belly 4 of the pin 1 is coated with a suitable resin by immersing the belly in a resin bath 9 to the horizontal dotted line 6, as shown in FIG. 3. Only the belly surfaces contact and absorb the resin since the base surfaces are sealed with wax. This keeps the base surfaces from absorbing resin and increasing the pins weight unnecessan'ly. The resin wets the wood fibers, for the following compression steps, and cures after the compression step to aid in holding or setting the fibers in their com-pressed state. As an example of a suitable resin, an epoxy resin may be used with a plasticizer added to provide the resin with the proper amount of flexibility in its cured state. A further example is a nylon resin dissolved in a volatile solvent. It should be understood that immersion is only one way of applying the resin and that it might be applied in other ways, for example, by spraying.

Compressing Pin Belly The belly 4 of the oversize pin 1 is compressed by simultaneously squeezing and turning it between three or more concave rollers rotating on axes circumferentially spaced around the pin and extending parallel to the pins longitudinal axis. This. step is illustrated in FIGS. .4 to

4 6. FIG. 6 shows the three

concave rollers

10, 11 and 12 positioned around a pin.

Each of the

rollers

10, 11 and 12 have identical concave curvatures. This concave curvature is slightly less (has a greater radius) than the vertical convex curvature of the oversize pin belly 4 so that the rollers compress the pin belly equator a maximum amount and the roller portions above and below the equator compress the pin belly progressively lesser amounts the farther they are spaced from the equator until reaching the end edges of the roller concavity where little or no compression of the pin takes place. This makes it possible to eliminate any definite demarcation lines between the compressed and uncompressed areas of the pin 1. This difference between the curvatures of the pin belly and the roller is shown in FIG. 4, illustrating the initial engagement of the pin belly 4 with the roller 12 as the

rollers

10, 11 and 12 are initially forced together on the pin. The concave curvature of the roller 12 being less than the vertical curvature of the pin belly 4, the initial engagement between the roller and the pin belly is limited to the pins equator. The

rollers

10, 11 and 12 may be either heated or unheated, but preferably they are unheated.

At-least one and preferably two of the

rollers

10, 11

and 12 are rotated about their vertical axes and their engagement with the pin 1 turns and rotates it about its longitudinal axis between all three rollers. As the force squeezing the rollers against the turning pin belly is slowly and progressively increased, the rollers progressively rollcompress the pin belly surface with the maximum amount of compression taking place at the equator of the pin belly, due to the lesser degree of curvature of the rollers. The force squeezing the rollers together on the pin is controlled to compress the oversize pin about Ma inch at its equator, thus compressing the pins equator to substantially its final size, the pin being about A; inch oversize. This stage of the pin compression is seen in FIG. 5. Note that in FIG. 5, the upper and lower edges of the roller 12 are not pressed into the pin, but are aligned with the uncompressed surfaces of the pin. Actually, due to the spring-back of the wood fibers after the release of the pin from the rollers, the rollers may be controlled to compress the pin slightly more than M; inch at its equator so that, after it is released and the wood fibers have sprung back, the pin remains compressed about A; inch at its equator.

Turning to Final Size After releasing the compressed pin from its compression rollers, itis placed in a lathe and turned to final size as shown schematically in FIG. 7. During this final turning, very little or no wood is removed from the equator of the pin belly as the pin was compressed to final size at this point by the compression rollers. The dotted lines 2- indicate thefinal profile of the pin after it has been finally turned.

COMPRESSION MACHINEFIGS. 8-11 The machine for roll-compressing a bowling pin belly comprises a frame 19 including a lower plate 20, an upper plate 21 overlying and vertically spaced from the lower plate 20 and a plurality ofvertical posts 22, one at each pair of. vertically aligned corners of the

plates

20 and 21, rigidly interconnecting the plates together.

The left end of the frame 19 carries a pair of transversely spaced concave rollers 10 and 11 pivotally mounted on parallel-vertical axes between the lower and

upper plates

20 and 21 with the ends of the rollers journalled in suitable bearings fixed on the-respective lower and upper plates. Each of the rollers 10 and 11 are equally spaced transversely on the opposite sides of the longitud inal center line of the frame 19 with the spacing between the facing surfaces of the concave rollers being about 25% less'th'an the corresponding width of the bowling pin belly that is to be compressed by the rollers;

The third concave roller 12 is pivoted on a vertical axis extending through the longitudinal center line of the frame 19 with its ends journalled in bearings carried at the free ends of a sliding U-shaped carriage 23 having upper and lower horizontal legs 24 joined by a vertical bight 25. The U-shaped carriage 23 is dimensioned to slide snugly between the lower and

upper plates

20 and 21 along the longitudinal center of the machine frame 19, and is guided during its travel by guide bars 26 fixed respectively to the opposing faces of the lower and

upper plates

20 and 21.

As previously explained, the

rollers

10, 11 and 12 may be either heated or unheated. No means is shown for heating the rollers, but this may be done, for example, by electric heating coils embedded in the rollers.

The upper plate 21 has a pear-shaped hole 27 through which a bowling pin is inserted into and removed from the machine. To compress a pin belly, the pin is dropped base-down through the hole 27 and the roller 12 is forced against the pin, which in turn forces the pin against the other rollers and 11, while the rollers 10 and 11 are slowly rotated in unison.

The mechanism for slowly rotating the rollers 10 and 11 is mounted at the left end of the frame 19 and includes a motor 29 fixed on the upper plate 21 and having a pinion 30 keyed on its shaft. The pinion 30 drives a larger gear 31 fixed at the upper end of a vertical shaft 32 that is journalled in bearings fixed to the lower and upper plates and 21. The lower end of the shaft 32 projects below the lower plate 20 and has a gear 33 fixed thereto which is in simultaneous driving engagement with pinions 34 and 34' fixed to the respective lower ends of the rollers 10 and 11. Hence, the motor 29 drives the rollers 10 and 11 through its pinion 39, gear 31, shaft 32, gear 33 and respective pinions 34 and 34' fixed to the rollers 10 and 11. In an example machine, I have selected the motor speed and gear ratios so that the bowling pin being compressed is rotated between the

rollers

10, 11 and 12 at about 11 rpm.

The mechanism for forcing the traveling roller 12 toward the rollers 10 and 11 includes a hydraulic jack 36 interposed between the rear of the U-shaped carriage bight and a vertical I-beam 37 fixed at the right end of the frame 19 between the lower and

upper plates

20 and 21. The hydraulic jack is operated from a suitable hydraulic pump 38, schematically illustrated in FIG. 8.

An adjustable stop means is provided for limiting the forward travel of the roller 12 toward the rollers 10 and 11 and includes a horizontal cross bar 39 mounted across the forward path of the U-shaped carriage bight 25. The cross bar 39 is attached at its opposite ends on vertical braces 40 extending between the lower and

upper plates

20 and 21 on the opposite sides of the U-shaped carriage path. A bolt 41, carrying a lock nut, is threaded through the center of the cross bar 39 and can be adjusted to abut thebight 25 and stop the forward travel of the roller 12 at a selected location.

MACHINE OPERATION Before operating the machine, it is assumed that the stop bolt 41 isproperly adjusted and locked in position to abut and stop the carriage 23, carrying the roller 12, at the desired location wherein a bowling pin is compressed the desired maximum amount. Also, the carriage 23 is retracted for the machine to receive a bowling pin.

To operate the machine, the motor 29 is energized to drive the rollers 10 and 11 at slow equal speeds, an oversized bowling pin 1 is dropped, base down, through the pear-shaped hole 27, and the pump 38 is actuated to start moving the roller 12 toward the bowling pin. As soon as the pin 1 is engaged between the three

rollers

10, 11 and 12, it starts rotating, due to its being driven by the rollers 10 and 11. The roller 12 also is driven about its axis by engagement with the rotating pin 1.

The hydraulic force of the hydraulic jack 36 pressing the roller 12 against the pin 1 is slowly and progressively increased to a predetermined maximum value and the pin is slowly and progressively compressed until the carn'age 23 is stopped against the stop bolt 41 which locks the roller 12 against further inward movement. In an example machine of mine, this predetermined value is 10,000 lbs. In this example machine, after the pin is in position between the rollers 10-12, hydraulic fluid pressure is admitted to the hydraulic jack 23 to move the roller 12 inwardly until the pin is initially engaged by all three rollers -1012. The hydraulic pressure now is increased to institute the compression of the wood. The pin usually rotates about six complete revolutions before the pressure in the jack 36 rises to the predetermined maximum value and the carriage 23 is stopped against the stop bolt 41. Thereafter, the pressure is held at the predetermined maximum value while the pin rotates about three to five complete revolutions. Since this particular machine is designed to rotate the pin at about 11 r.p.m., the compression of the pin takes about one minute.

After the pin 1 is compressed sufiiciently, the hydraulic pressure in the hydraulic jack 36 is released, the carriage 23 is retracted, and the pin I lifted upwardly through the pear-shaped hole 27, whereby the machine is ready to receive another oversize bowling pin.

MODIFIED METHODFIGS. 12-16 My modified method differs from that shown in FIGS. 1 to 7 by employing a starting bowling pin 45 having a slightly different shape. Unlike the oversize bowling pin 1 in FIG. 1, which is oversize over substantially its entire surface, the starting pin 45, shown in FIG. 12, is of final or finished size substantially over its head, neck and base portions 46-48 while its belly portion 49 is oversize. The extent to which the belly portion 49 is oversized, is indicated in FIGS. 14-15 by the crescent-shaped section 50 lying between outer line 51 representing the starting profile of the belly portion 49 of the starting pin and inner line 52 representing the final or finished contour of the belly portion of the compressed pin; Within practical limits, the radial and axial dimensions of section 50 may be varied in accordance with the range of compression and densification desired. I have obtained good results with, and therefore prefer, a section 50 having a radial dimension or thickness on the order of /a of an inch along the ball line 53 and an axial dimension approximating 2% inches with 1% inches on each side of the equator.

Prior to compression, the surface of the oversize belly portion 49 of the pin 45 is impregnated with or allowed to soak up some resin following the same procedure as described in'connection'with the method of FIGS. 1 to 7. Like the first method, this resin treatment is preferably limited to the belly 49 in'order' to avoid increasing the pins weight unnecessarily and this may be done by covering the base portion 48 of the pin with wax before dipping the pin in the resin, as shown in FIGS. 2 and 3.

After impregnation with resin, the oversize belly portion 49 of the pin 45 is compressed by the machine shown in FIGS. 8 to 11 in substantially the same manner as that used in the FIGS. 1 to 7 method. The only difference is that the concave compression rollers have a slightly different curvature. One of these rollers 54 is shown in FIGS. 12 and 13. The concave curvatures of the peripheral surfaces of all rollers 54 may be, and preferably are, the same. Such curvature, from one end of each roller to the other, may correspond precisely to the final vertical convex curvature desired in the belly portion of the finished pin. If desired, however, the periphery of the rollers 54 may be shaped so that their end portions remain out of contact with the pin as indicated at 55 in FIG. 16. The final compressed pin 45 does not necessarily need to be turned on a lathe since it is compressed to final shape and size. It may be lightly turned for smoothing purposes and then lightly sanded. Preferably it is lightly sanded only and this to the slight extent required to smooth its surface and prepareit for the application of its'finish coatings.

The densification characteristics of the compressed bowling pin 45 are indicated in FIGS. 14 and 15, which respectively show the pins belly before and after compression. The dotted lines used in these figures are intended to illustrate density. Thus, in FIG. 14, the dotted lines are equally spaced to indicate that the wood is not compressed or densified.

In FIG. 15, the dotted lines are more closely spaced along the ball line 53 of the pin than elsewhere. The spacing used in FIG. 15 is not intended to portray the changed density of the pin accurately but is intended generally to indicate that the densification of the wood is at a maximum along the circular equator 53 and that it progressively decreases not only radially in an inward direction from equator 53 but also axially in opposite directions from equator 53. Accordingly, it will be appreciated that, since the thickness of section 50 varied from a maximum at the equator 53 to zero at its upper and lower end edges, the increased density of the final pin changes progressively in a like manner; hence, in proportion to th original thickness of section 50.

The actual ball-impact line or ball-line is located below the equator 53 in order to impart a lift to the pin when it is hit by a ball. With repeated impacts, the conventional pin is compressed along the impact line. As a result, the lifting action of the impact is increased. This is objectionable. By precompressing this section, my invention tends to resist further compression by impact and correspondingly minimizes the increase in lift which normally accompanies use.

Having described my invention, I claim:

1. A method of compressing and densifying the impact zone of a bowling pin comprising: providing a bowling pin having an impact zone of predetermined convexity and equator diameter; placing said pin between a plurality of rotatable concave rollers providing a pin-receiving space of relatively less convexity than said predetermined convexity and having axes extending parallelto the longitudinalaxis of said pin in .said space; rotating at least one of said rollers; and progressively reducing the spacing between rollers so as to bring the equator of the pin into pin-rotating engagement with a corresponding portion of the rollers and thereafter to compress the impact zone of the pin in a progressive manner providing maximum compression along the equator of the pin and compression of progressively decreasing degree across the impact zone in axial directions proceeding away from the equator. V

2. The method of claim 1 wherein: said rollers are heated.

3. The method of claim 1 including: before the compression step, the step of coating the bowling pin with a suitable resin which wets the wood fibers to allow them to. be compressed more readily and which sets after compression to lock the wood fibersin their compressed state.

4. The method ofclaim 1 including: compressing said pin to reduce itsequator diameter at least /s inch.

5. The methodof claim lwhereinz said compressing step is performed 'byat least three concave rollers circumferentially' spaced around the :bowling pin.

' 6. The method .0f'.CiBiII1 5 wherein:. the spacing be- A 8 tweentherollers is reducedby rnovingpne of-said rollers toward the other rollers.-

7. The method of claim 1 including: compressingsaid pin to substantially its final equator diameter.

8. The method of claim 7 including; finishing the .compressed bowling pin by cutting its surfaces to final size along those areas which are not compressed in final size.

9. The method of claim 1 including: compressing the belly portion of the pin substantially to its final finished contour.

10. The method of claim 1 wherein: the providing step is performed by providing a bowling pin having head, neck and base portions substantially of final finished size and an oversized belly portion which progressively decreases in oversize across the impact zone in axial direc-' tions proceeding away from the equator; and the rollerspacing reducing step is performed with rollers shaped to compress the oversize belly portion substantially to final finished size.

11, A method of compressing and densifying a bowling pin having an impact zone extending horizontally around and vertically across the belly of the pin and being more or less centered on an equator which encircles the pin in the horizontal plane of its maximum belly diameter, com prising: providing a pin having a predetermined diameter at its equator and a predetermined large convexity vertically across its impact zone; providing a plurality of concave compression members, each having a concave cornpressing surface which is vertically dimensioned to embrace said impact zone and which is concavely curved to conform to a predetermined degree of vertical convexity smaller than said large convexity; and compressing the impact zone of said pin from said large convexity to ,a smaller convexity, said compression operation including the step of forcing said compression members compressively against the impact zone of said pin in a manner such as to effect a maximum degree of compression at said equator and a progressivelydecreasing degree of compression proceeding in both directionsvertically away from said equator.

12. The method of claim 11 wherein said forcingstep is performed in a'manner such as to institute compression at and across said equator but only partially across-said impact zone and thereafter progressively increase the de gree of compression at saidequator' up to a predetermined amount and contemporaneously widen the bandof compression across" said zone in a progressive manner proceeding in both directions vertically away from said equator while maintaining a compressive pressure gradient which also progressively decreases in both directions proceeding vertically away from said equator.

References Cited in the file of this-patent UNITED STATES PATENTS 7