SHAKER BOARD FOR BOWLING PINSETTER
United States Patent 3751036
A shaker board to receive and agitate the bowling pins and ball in the pit of a bowling alley. A frame having upwardly turned rear corner portions supports and shapes a sheet-like outer member formed of fiberglass reinforced polyester resin or polyepoxite resin. Generally tetrahedral shaped compartments are formed in the upwardly turned corner portions of the outer member and these compartments are filled with a fiberglass filler material to strengthen the shaker board. Apertures are provided at the front edge of the shaker board to bolt the board to a shaking mechanism. A carpet covering is adhesively secured to the upper surface of the outer member.
US Patent References:
NON-PLANAR BALL REBOUND WALL
McDougall - October 1972 - 3697068
FIBER GLASS DIVING BOARD HAVING INNER FRAME
Meyer - March 1970 - 3502327
Bowling alley
Riley - May 1954 - 2679396
Pit board with quick release clamps
Rogers et al. - June 1965 - 3188085
NON-PLANAR BALL REBOUND WALL
McDougall - October 1972 - 3697068
FIBER GLASS DIVING BOARD HAVING INNER FRAME
Meyer - March 1970 - 3502327
Bowling alley
Riley - May 1954 - 2679396
Pit board with quick release clamps
Rogers et al. - June 1965 - 3188085
Application Number:
05/236075
Publication Date:
08/07/1973
Filing Date:
03/20/1972
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
273/DIG.007, 264/257, 273/DIG.003, 273/DIG.009
International Classes:
A63D5/08; A63D5/00; A63D5/00
Field of Search:
273/43R,43A,51,DIG.7,DIG.9,DIG 3/ 272/66 264/271,273,274
Other References:
Brunswick Service Parts Catalog, Revision May, 1961, page 38..
Primary Examiner:
Oechsle, Anton O.
Claims:
I claim
1. A shaker board comprising:
2. The shaker board of claim 1, wherein said covering is a fiberglass reinforced polyester resin material.
3. The shaker board of claim 1, wherein:
4. The shaker board means of claim 3, wherein, said means to mount said shaker board means are apertures therethrough in the front edge thereof.
1. A shaker board comprising:
2. The shaker board of claim 1, wherein said covering is a fiberglass reinforced polyester resin material.
3. The shaker board of claim 1, wherein:
4. The shaker board means of claim 3, wherein, said means to mount said shaker board means are apertures therethrough in the front edge thereof.
Description:
Numerous types and makes of bowling pinsetters and bowling pit clearing devices and bowling pinsetting machines are known in the prior art as operable to receive bowling pins and bowling balls from the bowling alley, separate same, return the ball to the player, and reset the pins on the bowling alley in an automatic operation. One type of bowling pit clearing device utilizes a shaker board placed behind the normal setting position of the pins and below the surface of the alley to receive the bowling pins and the ball as they move from the alley and feed them into a circular pick up wheel. The shaker board moves in a forward and aft agitating motion wherein the pins and the ball are directed to the rear portion of the shaker board, whereupon they are caught up by the pick up wheel, the pins placed for resetting on the alley, and the ball moved into the gutter for return to the bowler. In operation the pick up wheel rotates in a vertical position adjacent to the rear of the shaker board, and the ball and pins pass from the shaker board into it. The shaker board is in a substantially horizontal position, and the bowling pins and ball strike it coming from a vertical direction after being knocked from the alley by the ball and directed downward by the sides and top portion of the alley end enclosure. The force with which the pins and the ball strike the shaker board depends upon the number of pins striking the board at any one time and the force with which the ball is thrown at the pins.
In these prior art devices the shaker boards are constructed of a laminated wooden member having metal corner fittings to shape the pick up wheel end and are covered by a carpet for protection of the pins and balls. In operation of pit clearing devices using these prior art shaker boards, the boards tend to break in the center due to the high impact force of the bowling ball and bowling pins in combination with the agitation of the board. Additionally, the prior art shaker boards will fracture in the center due to the downwardly directed force and at the upturned corner portions along the triangular shape of the corner fittings. In addition to fracturing of the shaker board structure, the prior art devices are substantially rigid in construction and only flex a small amount; therefore, the carpet attached to the upper surface of the shaker boards tends to wear heavily in the center of the board and along the corner fittings. The life expectancy of a prior art type shaker board, of course, depends upon the amount of usage it receives. A nominal and anticipated life expectancy for such boards is in the range of 3 weeks to 6 months, and seldom longer than 6 months. Additionally, during the lifetime of the shaker boards, the carpet covering the upper surface of the board will wear considerably and must be replaced in order that the bowling pins, and more importantly the bowling ball, will not be nicked, cut, or otherwise damaged. It is a current practice to use a high quality of carpet to cover the prior art type of shaker boards; although such is expensive, it provides the longest wearing characteristics. When a shaker board fails, the board and the carpet must be replaced before operation of the bowling pinsetter can be resumed. This is costly in terms of labor and replacement parts and is frustrating for a bowler who has not finished a game when the machine breaks.
In one preferred specific embodiment of this invention, a shaker board structure includes a frame having trusses on the sides thereof with stringers connecting the trusses, and the entire frame being covered with a resilient fiberglass reinforced plastic material. The frame has a truss member on each side thereof forming the upturned corners and sides of the shaker board with the stringers connecting the ends of the truss forming opposing forward and rear sides of the shaker board. The covering of the shaker board forms an upper member on which the carpet is attached. The covering is integrally constructed with the frame and preferably formed in a mold and completely enclosing the upturned corners on the lower surface of the board. The shaker board is constructed to be mounted in place of a prior art type shaker board on an existing bowling pit clearing device.
One object of this invention is to provide a shaker board for an automatic bowling pinsetting device having a frame structure covered with a fiberglass reinforced plastic material.
Still, another object of this invention is to provide a shaker board structure for an automatic bowling pinsetter which has an upper member and an integrally constructed frame structure which is adapted to replace a conventional shaker board structure in existing automatic bowling pinsetters.
Yet, another object of this invention is to provide a shaker board structure for an automatic bowling pinsetter constructed of a fiberglass reinforced plastic material which will flex in operation, particularly upon receipt of bowling pins and bowling balls, and return to its original shape time and time again.
Yet, one further object of this invention is to provide a shaker board for an automatic bowling pinsetter which has a frame including truss members on the sides thereof connected by stringer members on the forward and rear portions and which has a covering of fiberglass reinforced plastic material forming the upper member of the shaker board and integrally enclosing the frame.
Various other objects, advantages, and features of the invention will become apparent to those skilled in the art from the following discussion, taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a perspective view of the shaker board taken from above the forward end portion and having a segment of carpet on the upper surface thereof;
FIG. 2 is a rear side elevation view of the shaker board with a portion of one corner cut away showing the corner filling material;
FIG. 3 is a front side elevation view of the shaker board showing it attached to a part of the shaking mechanism;
FIG. 4 is a side elevation view of the shaker board showing in dashed lines the enclosed frame structure; and
FIG. 5 is a perspective view of one end portion of the frame structure alone showing in dashed lines pin portions of the frame structure inserted into the stringers.
The following is a discussion and description of preferred specific embodiments of the shaker board structure of this invention, such being made with reference to the drawings, whereupon the same reference numerals are used to indicate the same or similar parts and/or structure. It is to be understood that such discussion and description is not to unduly limit the scope of the invention.
Referring to the drawing in detail and in particular to FIG. 1, the shaker board structure of this invention, generally indicated at 10, is shown alone with a portion of the covering carpet 12 on one corner thereof. The shaker board structure 10 includes a frame structure, generally indicated at 14, a portion of which is shown in FIG. 5, and a covering, generally indicated at 16, formed over the frame structure 14 in the shape shown in FIG. 1. The shaker board structure 10 is preferably a molded plastic resin structure reinforced with fiberglass having the frame structure 14 enclosed therein below an outer member 17 on its upper surface.
The shaker board structure 10 of this invention is designed and adapted to replace and operate in a Brunswick Automatic Pinsetter, a product of the Brunswick Corporation of Chicago, Ill. Investigators have shown that the Brunswick Corporation manufactures several different models of automatic pinsetters, and the shaker boards used in them are substantially the same.
Generally, the shaker board structure is a unitary structure having a rectangular planform as shown in FIG. 1. The shaker board structure has a curved rear or first edge portion 18 with upturned ends forming corners 20 of the outer member 17 and having a first side portion 22 extending downward from the edge. The curvature of the rear edge portion 18 is nearly circular to match the pick up wheel as previously described. The shaker board 10 has second and third edge portions indicated at 24 and 26, respectively, connecting the curved rear edge portion 18 to the straight forward edge portion on the sides of the structure. The second and third side edge portions 24 and 26 have upright sides 28 and 30, respectively, extending downward from the edges of the outer member 17. The edge portion opposite the rear edge portion 18 is a forth or forward edge portion 32 extending between the second and third side edge portions 24 and 26, respectively. The fourth or rear edge portion 32 is not provided with downwardly extending sides.
FIG. 2 shows the rear side of the shaker board structure; it preferably has the somewhat circularly curved shape as shown generally in this figure, such presenting the outlet end of a trough in appearance. The rear side 22 is bounded on its upper surface by the first edge portion 18 and on its lower surface by a bottom edge 34, and on the sides by the second and third side portions 28 and 30, respectively. As shown, the rear side 22 does not extend to the lowermost portion of the second and third edge side portions. The bottom edge 34 is above the lowermost end of the second and third edge sides 28 and 30; such is necessary for use of the shaker board 10 in the identified automatic pinsetter. The curved rear side 22 has a pair of cutouts 36 on its outer end portions adapted to provide clearance for the shaker board in the identified bowling pinsetter machine structure.
FIG. 3 shows the shaker board structure 10 from the forward edge side 32. The forward edge portion 32 has a straight upper surface indicated at 38 and a straight lower surface indicated at 40. It is to be noted that the lower surface 40 does not extend to the lower portions of the second and third edge sides 24 and 30; this is necessary for the shaker board to operate in the identified bowling pinsetter. The rear edge portion 32 has a pair of apertures 42, one on each of its outer portions as shown in the drawing. The apertures 42 are used to mount the shaker board 10 in the bowling pinsetter.
A portion of the shaking mechanism is shown by the bar 43 bolted to the bottom of the forward edge portion 32 in FIG. 3. In the identified pinsetter the shaker board rests on a resiliently supported frame and is bolted to by the bar 43. The resiliently supported frame is agitated in an oscillating motion in line with the alley, thereby moving the shaker board in a forward and rearward oscillating motion.
As can be seen in FIG. 3 the bottom edge of the rear edge side 34 extends below the plane of the lower surface 40 of the forward edge portion, and the peaks of the corners, indicated at 20, extend a substantial distance above the upper surface 38 of the forward edge portion. In comparing FIG. 2 and FIG. 3 it is obvious the curved rear edge portion 18 is formed to be below the straight forward edge portion 32. It is to be noted that the relative shapes and physical sizes of the first edge portion 18, straight edge portion 32, and the side portions 28 and 30 depend upon the structure of the particular bowling pinsetter machine in which the shaker board structure 10 is to be placed. For the identified Brunswick Corporation pinsetters the shaker boards are the same physical size; however, the herein described invention can be constructed to be used on other machines requiring a different size of shaker board.
FIG. 4 shows the third side 30 of the shaker board structure 10. Both sides of the shaker board structure 10 are similar. As shown in FIG. 4, the outer member 17 joins with the side member 30 with a curved shape on the upper surface as shown. The bottom surface of the upper member is indicated at 35; it extends below the lower edge 44 of the sides 28 and 30 at its lowermost portion.
FIG. 5 shows the frame structure of the shaker board 10. Basically, the frame structure 14 includes a truss, indicated generally at 48, and a pair of stringers, one of which is indicated at 50 on the rear edge portion of the frame structure and the other, 52, at the forward edge portion of the structure. The truss 18 includes an upper elongated curved portion 54 to be positioned at the side edge of the upper member 17, a lower elongated portion 56 to form the lower edge of the second and third sides, and intermediate stiffener members 58 welded between the upper and lower truss members 54 and 56, respectively. The stiffener members 58 are in a spaced relation and are positioned so as to stiffen the truss for vertical loading. A generally triangularly shaped plate member 60 is provided in the enlarged end of the truss 48 positioned between the curved upper truss member 54 and the end truss member 62. The rear edge stringer 50 is secured to the truss 48 by a pin member 64 extending from the truss end member 62 into an aperture in the end of the stringer member 50 as shown. The forward edge stringer member 52 is secured to the truss 48 by the tip 66 of the upper truss member 54 extending into an aperture in the stringer member 52 and by another tip 68 on the end of the lower truss member 56 extending into an aperture of the stringer member 52. It is to be noted that the rear edge stringer member 50 is curved as shown in the drawing to conform with the required shape of the rear edge portion 18. Also, a notch 70 is made in the stringer 50 in conjunction with the notches 36 in the bottom edge of the rear side portion 34; these notches do not substantially lessen the strength of the structure and are necessary for proper clearance of the shaker board 10 in the identified bowling pinsetter. Additionally, it is to be noted that an aperture 72 is placed in the straight edge stringer 52 and as previously described in conjunction with aperture 42 and FIG. 3. The plate 60 provides additional stiffening of the enlarged end of the frame structure 14 which in practice has been found necessary to withstand the impact loading of bowling balls and pins striking the surface of the outer member 17.
In the preferred construction of the shaker board 10 of this invention, it is assembled in a mold in an inverted position with the outer member 17 on the bottom wherein the outer member 17 and the sides 22, 28, 30, and the rear of the straight edge portions are laid in the mold layers of fiberglass cloth and plastic-like resin; then the frame structure 14 is placed in the mold; then the frame structure 14 is wrapped in layers of fiberglass cloth and impregnated with the plastic resin. In the corner portions 20 of the shaker board structure 10 is formed a somewhat tetrahedral shaped compartment when overlayed with the fiberglass cloth. This tetrahedral compartment is bounded by the corner portion of the outer member 17, the outer end portion of the rear edge side 22, the rear end portion of the other sides 28 or 30, and a layer of fiberglass cloth and a plastic-like material formed over the rear stringer 50 and extending forward joining the bottom surface of the outer member 17. The bottom member of the shaker board structure is not visible in the drawings. The tetrahedral compartment is generally indicated at 76 in FIG. 2 and is preferably filled with a fiberglass filler material indicated at 78. Filling of the tetrahedral compartment 76 adds to the strength and resiliency of the shaker board structure. Once the shaker board structure has been molded, the apertures 42 and notches 36 are made in the structure in their proper positions, and the carpet covering 12 is adhesively secured to the upper surface of the outer member 17. In practice it has been found preferable to use fiberglass reinforced polyester resin or polyepoxite resin because of the desirable resiliency characteristics of these materials. Additionally, in construction of the frame structure 14 of this invention, practice has shown the necessity of the upright stiffeners 58 and the stiffening plate 60 in order to prevent fracture of the shaker board structure along the edge portions.
In the manufacture of the shaker board structure of this invention, it is obvious that the shaker board structure 10 is constructed in a sufficiently strong and resilient nature to achieve the end product and provide an improvement in bowling pinsetter shaker boards. The shaker board structure 10 is manufacturable as a replacement unit for the shaker board structure of the identified conventional and popular automatic bowling pinsetter and other similarly constructed units. The shaker board can be manufactured by similar methods and molding techniques used presently in the manufacture of fiberglass reinforced plastic resin structures without a need for unique processes or construction devices other than the mold. The named preferred material of construction has been found in practice to be preferable due to its easy handling and manufacturing characteristics as well as its strength and resiliency in the end product.
In the use and operation of the shaker board for bowling pinsetters of this invention, it is seen that same provides a replacement for and an improvement in the shaker board structure used in conventional automatic pinsetters. In the practice and use of the herein described invention, it has been found to have a performance which is substantially an improvement over the performance of prior art shaker boards. The shaker board structure 10 provides an improvement by in use performing for a much longer period than conventional shaker boards without failure or indication of failure. Additionally, the shaker board structure of this invention due to its resilient nature enables the carpet 12 fixed to the upper member to be of a lesser grade than the quality required previously, thus resulting in a lower cost. Another feature of the resilient nature of this shaker board 10 is that it will cause lesser damage to the bowling pins and the bowling ball due to its resiliently yielding under their impact force.
As will become apparent from the foregoing description of the applicant's shaker board for bowling pinsetter, relatively inexpensive and simple means have been provided to improve the shaker board portion of an automatic pinsetter device. The shaker board structure is easily manufactured by conventional fiberglass and plastic resin manufacturing techniques, simple to use in that it is installed in place of the conventional shaker board, and in practice has been shown to have a very long life due to its resilient nature. The shaker board structure is overall an economical structure in that it reduces the necessity of periodic replacement of shaker boards and their covering carpets in the named automatic pinsetter.
While the invention has been described in conjunction with preferred specific embodiments thereof, it will be understood that this description is intended to illustrate and not to limit the scope of the invention, which is defined by the following claims.
In these prior art devices the shaker boards are constructed of a laminated wooden member having metal corner fittings to shape the pick up wheel end and are covered by a carpet for protection of the pins and balls. In operation of pit clearing devices using these prior art shaker boards, the boards tend to break in the center due to the high impact force of the bowling ball and bowling pins in combination with the agitation of the board. Additionally, the prior art shaker boards will fracture in the center due to the downwardly directed force and at the upturned corner portions along the triangular shape of the corner fittings. In addition to fracturing of the shaker board structure, the prior art devices are substantially rigid in construction and only flex a small amount; therefore, the carpet attached to the upper surface of the shaker boards tends to wear heavily in the center of the board and along the corner fittings. The life expectancy of a prior art type shaker board, of course, depends upon the amount of usage it receives. A nominal and anticipated life expectancy for such boards is in the range of 3 weeks to 6 months, and seldom longer than 6 months. Additionally, during the lifetime of the shaker boards, the carpet covering the upper surface of the board will wear considerably and must be replaced in order that the bowling pins, and more importantly the bowling ball, will not be nicked, cut, or otherwise damaged. It is a current practice to use a high quality of carpet to cover the prior art type of shaker boards; although such is expensive, it provides the longest wearing characteristics. When a shaker board fails, the board and the carpet must be replaced before operation of the bowling pinsetter can be resumed. This is costly in terms of labor and replacement parts and is frustrating for a bowler who has not finished a game when the machine breaks.
In one preferred specific embodiment of this invention, a shaker board structure includes a frame having trusses on the sides thereof with stringers connecting the trusses, and the entire frame being covered with a resilient fiberglass reinforced plastic material. The frame has a truss member on each side thereof forming the upturned corners and sides of the shaker board with the stringers connecting the ends of the truss forming opposing forward and rear sides of the shaker board. The covering of the shaker board forms an upper member on which the carpet is attached. The covering is integrally constructed with the frame and preferably formed in a mold and completely enclosing the upturned corners on the lower surface of the board. The shaker board is constructed to be mounted in place of a prior art type shaker board on an existing bowling pit clearing device.
One object of this invention is to provide a shaker board for an automatic bowling pinsetting device having a frame structure covered with a fiberglass reinforced plastic material.
Still, another object of this invention is to provide a shaker board structure for an automatic bowling pinsetter which has an upper member and an integrally constructed frame structure which is adapted to replace a conventional shaker board structure in existing automatic bowling pinsetters.
Yet, another object of this invention is to provide a shaker board structure for an automatic bowling pinsetter constructed of a fiberglass reinforced plastic material which will flex in operation, particularly upon receipt of bowling pins and bowling balls, and return to its original shape time and time again.
Yet, one further object of this invention is to provide a shaker board for an automatic bowling pinsetter which has a frame including truss members on the sides thereof connected by stringer members on the forward and rear portions and which has a covering of fiberglass reinforced plastic material forming the upper member of the shaker board and integrally enclosing the frame.
Various other objects, advantages, and features of the invention will become apparent to those skilled in the art from the following discussion, taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a perspective view of the shaker board taken from above the forward end portion and having a segment of carpet on the upper surface thereof;
FIG. 2 is a rear side elevation view of the shaker board with a portion of one corner cut away showing the corner filling material;
FIG. 3 is a front side elevation view of the shaker board showing it attached to a part of the shaking mechanism;
FIG. 4 is a side elevation view of the shaker board showing in dashed lines the enclosed frame structure; and
FIG. 5 is a perspective view of one end portion of the frame structure alone showing in dashed lines pin portions of the frame structure inserted into the stringers.
The following is a discussion and description of preferred specific embodiments of the shaker board structure of this invention, such being made with reference to the drawings, whereupon the same reference numerals are used to indicate the same or similar parts and/or structure. It is to be understood that such discussion and description is not to unduly limit the scope of the invention.
Referring to the drawing in detail and in particular to FIG. 1, the shaker board structure of this invention, generally indicated at 10, is shown alone with a portion of the covering carpet 12 on one corner thereof. The shaker board structure 10 includes a frame structure, generally indicated at 14, a portion of which is shown in FIG. 5, and a covering, generally indicated at 16, formed over the frame structure 14 in the shape shown in FIG. 1. The shaker board structure 10 is preferably a molded plastic resin structure reinforced with fiberglass having the frame structure 14 enclosed therein below an outer member 17 on its upper surface.
The shaker board structure 10 of this invention is designed and adapted to replace and operate in a Brunswick Automatic Pinsetter, a product of the Brunswick Corporation of Chicago, Ill. Investigators have shown that the Brunswick Corporation manufactures several different models of automatic pinsetters, and the shaker boards used in them are substantially the same.
Generally, the shaker board structure is a unitary structure having a rectangular planform as shown in FIG. 1. The shaker board structure has a curved rear or first edge portion 18 with upturned ends forming corners 20 of the outer member 17 and having a first side portion 22 extending downward from the edge. The curvature of the rear edge portion 18 is nearly circular to match the pick up wheel as previously described. The shaker board 10 has second and third edge portions indicated at 24 and 26, respectively, connecting the curved rear edge portion 18 to the straight forward edge portion on the sides of the structure. The second and third side edge portions 24 and 26 have upright sides 28 and 30, respectively, extending downward from the edges of the outer member 17. The edge portion opposite the rear edge portion 18 is a forth or forward edge portion 32 extending between the second and third side edge portions 24 and 26, respectively. The fourth or rear edge portion 32 is not provided with downwardly extending sides.
FIG. 2 shows the rear side of the shaker board structure; it preferably has the somewhat circularly curved shape as shown generally in this figure, such presenting the outlet end of a trough in appearance. The rear side 22 is bounded on its upper surface by the first edge portion 18 and on its lower surface by a bottom edge 34, and on the sides by the second and third side portions 28 and 30, respectively. As shown, the rear side 22 does not extend to the lowermost portion of the second and third edge side portions. The bottom edge 34 is above the lowermost end of the second and third edge sides 28 and 30; such is necessary for use of the shaker board 10 in the identified automatic pinsetter. The curved rear side 22 has a pair of cutouts 36 on its outer end portions adapted to provide clearance for the shaker board in the identified bowling pinsetter machine structure.
FIG. 3 shows the shaker board structure 10 from the forward edge side 32. The forward edge portion 32 has a straight upper surface indicated at 38 and a straight lower surface indicated at 40. It is to be noted that the lower surface 40 does not extend to the lower portions of the second and third edge sides 24 and 30; this is necessary for the shaker board to operate in the identified bowling pinsetter. The rear edge portion 32 has a pair of apertures 42, one on each of its outer portions as shown in the drawing. The apertures 42 are used to mount the shaker board 10 in the bowling pinsetter.
A portion of the shaking mechanism is shown by the bar 43 bolted to the bottom of the forward edge portion 32 in FIG. 3. In the identified pinsetter the shaker board rests on a resiliently supported frame and is bolted to by the bar 43. The resiliently supported frame is agitated in an oscillating motion in line with the alley, thereby moving the shaker board in a forward and rearward oscillating motion.
As can be seen in FIG. 3 the bottom edge of the rear edge side 34 extends below the plane of the lower surface 40 of the forward edge portion, and the peaks of the corners, indicated at 20, extend a substantial distance above the upper surface 38 of the forward edge portion. In comparing FIG. 2 and FIG. 3 it is obvious the curved rear edge portion 18 is formed to be below the straight forward edge portion 32. It is to be noted that the relative shapes and physical sizes of the first edge portion 18, straight edge portion 32, and the side portions 28 and 30 depend upon the structure of the particular bowling pinsetter machine in which the shaker board structure 10 is to be placed. For the identified Brunswick Corporation pinsetters the shaker boards are the same physical size; however, the herein described invention can be constructed to be used on other machines requiring a different size of shaker board.
FIG. 4 shows the third side 30 of the shaker board structure 10. Both sides of the shaker board structure 10 are similar. As shown in FIG. 4, the outer member 17 joins with the side member 30 with a curved shape on the upper surface as shown. The bottom surface of the upper member is indicated at 35; it extends below the lower edge 44 of the sides 28 and 30 at its lowermost portion.
FIG. 5 shows the frame structure of the shaker board 10. Basically, the frame structure 14 includes a truss, indicated generally at 48, and a pair of stringers, one of which is indicated at 50 on the rear edge portion of the frame structure and the other, 52, at the forward edge portion of the structure. The truss 18 includes an upper elongated curved portion 54 to be positioned at the side edge of the upper member 17, a lower elongated portion 56 to form the lower edge of the second and third sides, and intermediate stiffener members 58 welded between the upper and lower truss members 54 and 56, respectively. The stiffener members 58 are in a spaced relation and are positioned so as to stiffen the truss for vertical loading. A generally triangularly shaped plate member 60 is provided in the enlarged end of the truss 48 positioned between the curved upper truss member 54 and the end truss member 62. The rear edge stringer 50 is secured to the truss 48 by a pin member 64 extending from the truss end member 62 into an aperture in the end of the stringer member 50 as shown. The forward edge stringer member 52 is secured to the truss 48 by the tip 66 of the upper truss member 54 extending into an aperture in the stringer member 52 and by another tip 68 on the end of the lower truss member 56 extending into an aperture of the stringer member 52. It is to be noted that the rear edge stringer member 50 is curved as shown in the drawing to conform with the required shape of the rear edge portion 18. Also, a notch 70 is made in the stringer 50 in conjunction with the notches 36 in the bottom edge of the rear side portion 34; these notches do not substantially lessen the strength of the structure and are necessary for proper clearance of the shaker board 10 in the identified bowling pinsetter. Additionally, it is to be noted that an aperture 72 is placed in the straight edge stringer 52 and as previously described in conjunction with aperture 42 and FIG. 3. The plate 60 provides additional stiffening of the enlarged end of the frame structure 14 which in practice has been found necessary to withstand the impact loading of bowling balls and pins striking the surface of the outer member 17.
In the preferred construction of the shaker board 10 of this invention, it is assembled in a mold in an inverted position with the outer member 17 on the bottom wherein the outer member 17 and the sides 22, 28, 30, and the rear of the straight edge portions are laid in the mold layers of fiberglass cloth and plastic-like resin; then the frame structure 14 is placed in the mold; then the frame structure 14 is wrapped in layers of fiberglass cloth and impregnated with the plastic resin. In the corner portions 20 of the shaker board structure 10 is formed a somewhat tetrahedral shaped compartment when overlayed with the fiberglass cloth. This tetrahedral compartment is bounded by the corner portion of the outer member 17, the outer end portion of the rear edge side 22, the rear end portion of the other sides 28 or 30, and a layer of fiberglass cloth and a plastic-like material formed over the rear stringer 50 and extending forward joining the bottom surface of the outer member 17. The bottom member of the shaker board structure is not visible in the drawings. The tetrahedral compartment is generally indicated at 76 in FIG. 2 and is preferably filled with a fiberglass filler material indicated at 78. Filling of the tetrahedral compartment 76 adds to the strength and resiliency of the shaker board structure. Once the shaker board structure has been molded, the apertures 42 and notches 36 are made in the structure in their proper positions, and the carpet covering 12 is adhesively secured to the upper surface of the outer member 17. In practice it has been found preferable to use fiberglass reinforced polyester resin or polyepoxite resin because of the desirable resiliency characteristics of these materials. Additionally, in construction of the frame structure 14 of this invention, practice has shown the necessity of the upright stiffeners 58 and the stiffening plate 60 in order to prevent fracture of the shaker board structure along the edge portions.
In the manufacture of the shaker board structure of this invention, it is obvious that the shaker board structure 10 is constructed in a sufficiently strong and resilient nature to achieve the end product and provide an improvement in bowling pinsetter shaker boards. The shaker board structure 10 is manufacturable as a replacement unit for the shaker board structure of the identified conventional and popular automatic bowling pinsetter and other similarly constructed units. The shaker board can be manufactured by similar methods and molding techniques used presently in the manufacture of fiberglass reinforced plastic resin structures without a need for unique processes or construction devices other than the mold. The named preferred material of construction has been found in practice to be preferable due to its easy handling and manufacturing characteristics as well as its strength and resiliency in the end product.
In the use and operation of the shaker board for bowling pinsetters of this invention, it is seen that same provides a replacement for and an improvement in the shaker board structure used in conventional automatic pinsetters. In the practice and use of the herein described invention, it has been found to have a performance which is substantially an improvement over the performance of prior art shaker boards. The shaker board structure 10 provides an improvement by in use performing for a much longer period than conventional shaker boards without failure or indication of failure. Additionally, the shaker board structure of this invention due to its resilient nature enables the carpet 12 fixed to the upper member to be of a lesser grade than the quality required previously, thus resulting in a lower cost. Another feature of the resilient nature of this shaker board 10 is that it will cause lesser damage to the bowling pins and the bowling ball due to its resiliently yielding under their impact force.
As will become apparent from the foregoing description of the applicant's shaker board for bowling pinsetter, relatively inexpensive and simple means have been provided to improve the shaker board portion of an automatic pinsetter device. The shaker board structure is easily manufactured by conventional fiberglass and plastic resin manufacturing techniques, simple to use in that it is installed in place of the conventional shaker board, and in practice has been shown to have a very long life due to its resilient nature. The shaker board structure is overall an economical structure in that it reduces the necessity of periodic replacement of shaker boards and their covering carpets in the named automatic pinsetter.
While the invention has been described in conjunction with preferred specific embodiments thereof, it will be understood that this description is intended to illustrate and not to limit the scope of the invention, which is defined by the following claims.