Combination 15-ball and 9-ball billiard ball rack

A combination billiard rack convertible between two game configuration, such as a 15-ball configuration and a 9-ball configuration. The rack includes two side members and a base member that cooperate to form a substantially equilateral triangle defining an interior area in a plane of the rack capable of receiving and racking a plurality of billiard balls. Pivotal arms are provided on each of the side members. Each is pivotal about one fixed end at a location proximate a midpoint of each side member for pivotal movement about the fixed end in the plane of the rack. The pivotal arms are pivotal between a first position in which each pivotal arm is parallel with corresponding side members and a second position located within said interior area in which the pivotal arms are non-parallel with corresponding side members and act with the side members and base member to form an internal area of a size smaller than the first configuration. One or more biased movable arms can be provided on the base member to allow fuller motion of the pivotal arms. The rack is releasably lockable in either of the two configurations.

BACKGROUND OF THE INVENTION 
1. Field of Invention 
The invention relates to an improved billiard ball rack that will allow 
multiple configurations of racked balls, particularly from a 15-ball 
equilateral triangle shape to a 9-ball diamond shape. 
2. Description of Related Art 
Various games fall under the general category of pocket billiards or pool. 
Balls in each game are arranged during certain times of these games in a 
pattern at a designated location on a pool table. A common pattern is an 
equilateral triangle shape using fifteen (15) numbered balls. Other games 
use a different number of balls and patterns, one of which is a diamond 
pattern using nine (9) numbered balls. Racks specifically shaped and sized 
in these patterns are used to align balls in such games. 
It is desirable to have one rack which can perform the racking 
responsibility for either a 9-ball or 15-ball game, as well as other 
billiard ball games. One benefit of such a rack is a reduction of cost to 
the owners of the billiard tables, by having to own and maintain one rack 
rather than several. A benefit to the players would also be achieved as 
the inconvenience of locating a second rack is eliminated. 
U.S. Pat. No. 5,376,054 to Kwasny et al. discloses a multiple use billiard 
ball rack useful in both a 15-ball configuration and a 9-ball 
configuration. Side (top) legs of the rack and a bottom leg are integral 
and form the outline of the 15-ball configuration. Each side leg includes 
an elongated slot in which movable leg members can move. A pin is provided 
at one end of the leg member. A pair of longitudinally directed ears 
define a groove in which the pin can slide. As best illustrated in FIGS. 
1-4, the leg members can be moved between a 15-ball configuration and a 
9-ball configuration. All embodiments teach that an end of the leg members 
opposite the pin should be affixed to the bottom leg of the rack by 
connecting elements as shown in FIGS. 1, 6, 7 and 8. This rack, while 
providing conversion between 9-ball and 15-ball configurations, achieves 
this using a difficult and complicated structure that requires many user 
movements in order to properly position and lock the rack in the nine ball 
configuration and return it to the fifteen ball configuration. 
U.S. Pat. No. 4,469,328 to Pacitti discloses a racking device for different 
billiards games that is convertible from a 15-ball configuration to a 
9-ball configuration. A rack includes integral leg members that form a 
triangular shape. A midpoint of two side leg members include hinges for 
securing a movable frame thereto. The movable frame is V-shaped and 
positionable between first and second positions. In the first position, 
the V-shape overlies a corresponding V-shape at the top of rack formed by 
upper portions of the leg members. This is a 15-ball configuration. In the 
second position, the V-shaped movable frame is pivoted 180.degree. about 
the hinges to form a lower half of an equilateral diamond to form a 9-ball 
configuration. See FIGS. 1, 4 and 6. While simple operation is achieved, 
this structure results in a rack with an increased height and can be 
difficult to use when balls are already located within the rack during 
transition between the two positions. Such a rack also is not capable of 
automatically aligning the balls into the new configuration. 
U.S. Design Pat. No. D315,942 to Cahill discloses the ornamental design for 
a pool rack triangle. As illustrated in FIG. 2, the rack includes a lower 
half that forms a 15-ball triangular rack configuration while the upper 
half subdivides a triangle into a diamond shape section suitable as a 
9-ball rack. 
U.S. Pat. No. 1,089,140 to Madigan discloses a pool frame that includes a 
base having spring hinges at ends thereof and two side bars attached to 
the spring hinges at one end thereof. Ends of the side bars opposite the 
spring hinges include latch plates for locking the frame into a triangular 
pool rack configuration. The purpose of the spring-loaded frame is to 
allow the frame to be opened (spread laterally) after racking of the pool 
balls so that the frame can be removed without displacing the balls. See 
FIG. 1. 
U.S. Pat. No. 1,725,494 to Varnum discloses a pool ball rack including a 
base member and side members. Ends of the base member have coil spring 
hinges that connect to an end of the side members. The springs urge the 
side members into a triangular pool rack configuration. The springs also 
act to squeeze together the balls. See FIG. 1. 
U.S. Pat. No. 3,992,005 to Richey discloses a billiard ball rack having 
three arms interconnected together in a triangular shape by rotating 
hinges. A biasing spring exerts a force on the hinges tending to position 
the rack in a closed position. See FIGS. 1-3. 
It is desirable to have a combination billiard rack that can simply and 
effectively convert from one game configuration to another configuration. 
Additionally, in most billiard racks, billiard balls must be placed in the 
appropriate shape, i.e., triangular or diamond, by a user. It is desirable 
to have a rack that can automatically align and position billiard balls 
within the rack when changing from one rack configuration to another with 
simple and reliable operation. 
It is also desirable for a billiard rack to be able to reliably and 
automatically lock in either a 9-ball or 15-ball configuration so that 
conversion can be effectively achieved with minimal user assistance. 
SUMMARY OF THE INVENTION 
It is an object of the invention to provide a combination billiard ball 
rack that can transform from an ordinary 15-ball configuration to a 
different configuration, such as a 9-ball configuration. 
It is a further object of the invention to provide a simple, easy to use 
billiard ball rack that can adapt to playing several games and is 
preferably releasably locked in multiple configurations. 
It is yet another object of the invention to provide a combination billiard 
ball rack that retains overall standard 15 ball size, i.e., standard side 
member and base member length and overall rack height. 
These and other objects are achieved by a combination billiard rack 
convertible between two game configuration, such as a 15-ball 
configuration and a 9-ball configuration. The rack includes two side 
members and a base member that cooperate to form an equilateral triangle 
defining an interior area in a plane of the rack capable of receiving and 
racking a plurality of billiard balls. Pivotal arms are provided on each 
of the side members. Each is pivotal about one fixed end at a location 
proximate a midpoint of each side member for pivotal movement about the 
fixed end in the plane of the rack. The pivotal arms are pivotal between a 
first position in which each pivotal arm is parallel with corresponding 
side members and a second position located within said interior area in 
which the pivotal arms are non-parallel with corresponding side members 
and act with the side members and base member to form an internal area of 
a size smaller than the first configuration. 
The base member preferably includes at least one pivotal arm that is biased 
to one position, but is pivotal out of the way of the pivotal arms of the 
side members, allowing fuller movement of the side member pivotal arms and 
lengthening of such arms. The pivotal arms are preferably designed to be 
removably fixed in two or more different positions, allowing static 
retention of the rack in any of the two configurations without application 
of external forces.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
With reference to FIG. 1, a billiard rack 10 according to the invention is 
shown in the normal fifteen ball configuration which will be designated as 
a first idle position. In the preferred construction the rack is made of 
wood, preferably hard wood. Rack 10 includes a pair of essentially flat 
side members 12 and a base member 14. Side members 12 are connected to 
each other at a common end portion 13 while opposing end portions 16 are 
connected to opposing ends of base member 14 to define a standard 
triangular enclosure area 11 for receiving and racking fifteen billiard 
balls 5. Such a triangular rack defines three substantially equal sides 
having a length L.sub.1 of approximately 32.8 cm. Although described as 
three separate elements, the rack 10 could be formed as a continuous 
piece, such as by molding or extruding a plastic or resin, or by forming, 
molding or welding a metal frame. 
Side members 12 and base member 14 include side inner surfaces 18, base 
inner surface 22, side outer surfaces 20, base outer surface 24, side and 
base top surface 21, and side and base bottom surface 19. Top and bottom 
surfaces 21, 19 are essentially flat and the bottom surface 19 may include 
an optional layer of material 23 applied to its surface, such as, but not 
limited to, felt, flock or Teflon. This optional surface may be provided 
to reduce wear and tear on the billiard table surface upon which rack 10 
is used. The top surface 21 may be designed wide enough to convey an 
advertising message such as the particular bar or billiard parlor owning 
the table, a particular tournament, or other commercial advertisements. 
Rack 10 can be made of any suitable rigid material such as hardwood, 
although plastic and metal could also be used. 
Side members 12 are each provided with pivotal arms 26, which are 
preferably separate pieces also constructed of rigid material and 
connected to side members 12 through spring hinges 28 or other suitable 
flexing devices that in releasing tension return the pivotal arm to the 
idle first position (15-ball configuration). Suitable spring hinges can be 
obtained from La Deau Manufacturing Corp., Glendale, Calif., part 
#Q9701151-1. Preferably, pivotal arms 26 maintain a uniform predetermined 
height H (See FIG. 5) of the rack 10. Pivotal arms 26 allow conversion of 
rack 10 from the standard triangular fifteen ball configuration to a nine 
ball configuration (second position) through simple pivotal movement of 
pivotal arms 26. Base member 14 is provided with pivotal arms 42, which 
like pivotal arms 26, are separate pieces formed preferably of rigid 
material and maintain the uniform height 25 of rack 10. Like pivotal arms 
26, pivotal arms 42 are attached to base member 14 through spring hinges 
28 or other suitable attachment and flexing devices. Pivotal arms 42 of 
the base member act so as to allow a fuller range of motion (angle 43) of 
pivotal arms 26 of side members 12. 
The invention allows simple, effective and precise conversion of the rack 
10 from the fifteen ball configuration to the nine ball configuration 
through the simple movement of pivotal arms 26 by application of a force F 
applied to outer surfaces of pivotal arms 26 (as shown in FIG. 2) by a 
user. Continued application of force F pivots the pivotal arms 26 through 
an angle .theta. to the intermediate position shown in FIG. 3. Upon 
angular rotation of pivotal arms 26, pivotal arms 26 contact pivotal arms 
42, causing them to pivot outward against the resistance of spring hinges 
28 as shown. Eventually, rack 10 assumes the nine ball configuration shown 
in FIG. 4. 
It should be noted that due to the specific preferred design of the rack, 
rack 10 becomes fixed in the new nine ball configuration, and will remain 
in such a configuration until a force F' is applied to pivotal arms 42 by 
a user. Then, upon sufficient rotation of pivotal arms 42 about their 
hinges 28, pivotal arms 26 will return to their original position in line 
with side members 12 due to the bias of springs 28. Upon release of force 
F', pivotal arms 42 return to their original position in line with base 
member 14. This returns the rack 10 back to the original fifteen ball 
configuration of FIG. 1. 
A more detailed description of rack operation will now be described 
referring back to FIG. 3. Pivotal arms 42 are attached at a center support 
47 of the base member 14 via springs 28. The bias of the springs pulls 
pivotal arms 42 towards the interior area 11 of the rack 10. Each pivotal 
arm 42 of base member 14 is prevented from entering the interior 11 by 
butt 46 of each pivotal arm 42 abutting against a vertical contact surface 
49 of the center support 47 and, additionally, this is achieved by beveled 
end 48 of the pivotal arm 42 contacting the inner surface 18 of side 
members 12. Likewise, pivotal arms 26 are prevented from extending outward 
beyond side members 12 by beveled end 41, which contacts a corresponding 
beveled edge 45, and by butt 50, which contacts vertical contact surface 
51. Beveled ends 41, 48 form an angle with the inner and outer surfaces. 
FIG. 5 shows a side view of the interior surface 18 of the left side member 
12. The interior surface 18 of the side member 12 has a uniform height H. 
An optional layer 23 of material is shown. FIGS. 6 and 7 show detailed 
views of spring hinges 28. In the preferred embodiment, spring hinges 28 
are mounted on the interior surfaces of side members 12, preferably not 
interrupting the flatness of the interior surface 18. This can be achieved 
by the use of recessed screw holes 31 in leaves 35 of the spring hinges 
and by mounting spring hinges 28 into recesses 29 (see FIG. 8) cut into 
pivotal arm 26 and side member 12 at an appropriate depth to maintain the 
continuity of the interior surface 18. Additionally, a recess 30 is cut 
into interior surface 18 of the side members 12 to compensate for the 
diameter D of knuckle 38 of spring hinge 28. To further maintain such 
continuity in interior surface 18, dimples 32 in leaves 35 contain ends 33 
of spring 34. The spring hinges 28 attached to pivotal arms 42 are 
likewise configured. Alternatively, other flexing devices could be used, 
such as nylon hinges, living hinges, memory retention metals or other 
devices that return the pivotal arms to their idle position (first 
position). 
With reference back to FIG. 1, the pivotal axis P of the pivotal arm 26 is 
laterally biased and located proximate to the midpoint of the side member 
12, yet closer to the union point 16 of the side member 12 and base member 
14 than to the union point 13 of the two side members. More particularly, 
the rack 10 includes an interior side (18) length L.sub.1 of approximately 
32.8 cm, a pivotal arm 26 length L.sub.2 of between 14.2 and 14.6 cm and a 
length L.sub.3 that is the difference of L.sub.1 minus L.sub.2 measured 
from the pivot point of the pivotal arm 26 to an inner top corner ITC of 
rack 10. The interior side 22 of base 14 also has a total length of 
approximately 32.8 cm as it is part of an equilateral triangle. Pivotal 
arms 42 each have a length L.sub.4 of between 13.5 and 14 cm. Center 
support 47 has a length L.sub.5, which is the total length L.sub.1 minus 
the two pivotal arm lengths L.sub.4. 
FIG. 9 is a cross-sectional view of FIG. 5 taken along line 9--9 showing a 
flat bottom 70 of pivotal arm 26 and a corresponding flat upper surface 72 
of side member 12. FIG. 10 is an alternative structure taken along line 
10--10 of FIG. 5. In the FIG. 10 embodiment, beveled end 41 and 
corresponding beveled edge 45 further include a beveled bottom surface 70' 
and a corresponding surface 72' of side member 12. The beveled surface 70' 
is at a suitable angle .alpha. so as to provide a stop that prevents 
excessive outward travel of pivotal arm 26. Pivotal arms 42 of base member 
14 can have a similar structure to prevent excessive inward travel of 
pivotal arms 42. 
FIG. 11 shows a perspective view of the FIG. 10 embodiment. The side member 
12 uses both a beveled corresponding surface 72' and beveled edge 45. This 
results in a complex converse interior angle 73 where the horizontal and 
vertical beveled surfaces meet. The bottom surface and end of pivotal arms 
26 are likewise configured to mate with the structure of the side member. 
FIGS. 12 and 13 show an alternative embodiment in which like numbers refer 
to like elements. Side members 12 and pivotal arms 26 are the same as 
other embodiments. However, pivotal arms 42' are provided with spring 
hinges 28' at their respective end nearest corner 16. Thus, the pivot 
points of pivotal arms 42' are located on the external surface 24 of base 
member 14 proximate the union 16 of the side member and the base member. 
This embodiment alters the center support 47' to include beveled interior 
vertical ends 62 that mate with corresponding beveled ends 61 of pivotal 
arms 42'. This embodiment achieves a structure in which the interior 
surface 22 is substantially flat. FIG. 12 shows a force F being applied to 
force pivotal arms 26 inward towards internal area 11. Upon rotation of 
pivotal arms 26 about their respective pivot axes, contact is made with 
modified pivotal arms 42' located on base member 14', which pivot as shown 
to allow fuller movement of pivotal arms 26 to achieve an unshown nine 
ball configuration in which pivotal arms 26 are positioned as in FIG. 4. 
FIG. 13 shows the alternative embodiment of FIG. 12 returned to an idle 
position (fifteen ball configuration). 
FIGS. 14-16 show a further alternative embodiment in which a modified base 
member 14" is provided. Side members 12 and pivotal arms 26 remain as in 
previous embodiments. However, base member 14" now includes a lower plate 
51 and an upper plate 52 pivotally connected by spring hinges 28" to allow 
pivotal movement as shown in FIG. 15. The lower plate 51 is preferably 
fixed to side members 12 while upper plate 52 is not fixed to side members 
12, and instead rests in an upright position on top of lower plate 51 when 
in an idle state. Upon application of a force F to pivotal arms 26 as 
shown in FIG. 16, pivotal arms 26 pivot inwards toward area 11 and contact 
the upper plate 52 of base member 14". This causes upper plate 52 to pivot 
as best illustrated in the cross-sectional view of FIG. 15 so as to allow 
fuller movement of pivotal arms 26. By proper selection of bias applied to 
hinges 28 and 28", the rack 10 is able to remain in either of the selected 
fifteen or nine ball configurations absent an external force F to revert 
the rack 10 back to the other of the two positions. 
The invention has been described with reference to specific preferred 
configurations, which are intended to be illustrative and not exhaustive. 
Various modifications and alterations will be apparent to one of ordinary 
skill in the art and are intended to fall within the scope of the appended 
claims. For example, the present invention can be practiced to a lesser 
extent without use of a base member having one or more pivotal arms or 
plates. In such a case, to allow for fuller movement of the pivotal arms 
on the side members, the pivotal arms can be made to a shorter length to 
prevent binding with the base member. Alternatively, the arms of the base 
member could be designed to move into the interior of the rack with the 
arms of the side members cooperating via motion away from the interior of 
the rack. 
Likewise, as previously noted, rack 10 could be made from a plastic or 
resin material with frame components by molding or extrusion. 
Alternatively, the rack could be machined or made of metal. The various 
components could be made by extruding or shaping or molding as appropriate 
with the basic frame joined to form a triangular shape by welding, 
riveting, crimping, nailing, gluing or other bonding. Although biased 
spring hinges are the preferred method of attachment and flexing, the 
pivotal arms of the frame could be formed of memory retentive materials 
and may or may not be integral to the frame. Integral living hinges and a 
plastic frame and pivotal arms are also contemplated as alternatives.