Bread pan fabricated of liquid-crystal polymer

A bakery pan formed of injection molded liquid-crystal polymer has side walls and end walls which include an integral rib for receiving and retaining an encircling strap enabling several of the pans to be supported together in a module. A ferrous or magnetic material member is secured to the bottom of the pan, enabling the non-ferrous pan to be used in magnetic conveyor systems, and the band used for holding the pans in a module also is a magnetic material to permit holding the pans with overhead magnets.

BACKGROUND OF THE INVENTION 
1. Field of the Invention. 
The present invention relates to bakeware and more specifically to a bread 
pan fabricated of a liquid-crystal polymer. 
2. Description of the Prior Art. 
Bakeware, and specifically bread pans, are presently fabricated of a 
variety of materials. In the commercial baking industry, the bakeware is 
typically fabricated of sheet metal. Metal bakeware has several 
disadvantages. The pans require greasing or glazing before each baking 
cycle so that the bakery product will not adhere to the pan following 
baking. The forming operation can form envelope folds which are unsanitary 
and also the folds tend to retain trapped acid from the glazing operation. 
The metal pans remain hot upon removal from the oven and therefore cannot 
be easily handled and then are relatively heavy and therefore somewhat 
burdensome to handle. Metal pans are also typically difficult to clean 
because of the sharp corners created during the metal-forming operations. 
Although bakeware has been fabricated of other materials, such pans also 
suffer disadvantages. For example, bakeware is sometimes fabricated of 
expensive but easily broken glass or ceramic material. These pans are 
therefore not suitable for the relatively rough handling in a commercial 
bakery environment, in which sets of pans may be dropped several feet onto 
concrete floors. 
Cookware suitable for microwave ovens is often injection-molded of 
thermoplastic materials. However, such materials often have relatively low 
melting points and therefore are also unsuitable for use at conventional 
baking temperatures. 
SUMMARY OF THE INVENTION 
The aforementioned problems are overcome in the present invention 
comprising a bread pan injection-molded of a liquid-crystal polymer. 
Liquid-crystal polymers have relatively high melting and softening points 
and are therefore well-suited for conventional baking pans. The material 
does not require grease or glazing prior to baking, since bakery products 
will not readily adhere to the material. Further, the exterior surfaces of 
the pans cool quickly upon removal from the oven and therefore can be 
immediately and easily handled by workers. The pans are relatively 
light-weight compared to metal, ceramic, and glass bakeware. Because the 
articles can be injection-molded, corners can be formed round to 
facilitate cleaning of the pans. The pans are extremely strong and 
particularly well-adapted to the rough handling of a commercial baking 
operation. 
In a preferred form of the invention, strap-retaining ribs are integrally 
molded into the exterior side wall of the pan, enabling the pans to be 
assembled into a set or module of pans used for baking. A (magnetic) 
material strip also can be carried by the pan bottom, enabling the pan to 
be transported by conventional magnetic conveyor systems. 
These and other objects, advantages, and features of the invention will be 
more readily understood and appreciated by reference to the detailed 
description of the preferred embodiment and the drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A bread pan fabricated in accordance with a preferred embodiment of the 
invention is illustrated in the drawings and generally designated 10. 
Generally speaking, the pan includes a pan body 12 as shown, molded from a 
liquid-crystal polymer. As shown a ferrous (magnetic material) strap 14 is 
secured, with rivets 15, to the pan bottom enabling the pan to be handled 
in conventional fashion by commercial bakery magnetic conveyors. The strip 
has to have the same temperature coefficient of expansion as the 
liquid-crystal polymer, or two separate ferrous or magnetic material discs 
can be used. The pan body includes a bottom 20 and two upright walls 21 
including side walls 22 and two end walls 23 integrally molded with the 
bottom 20 and extending upwardly therefrom. The walls 21 form a receptacle 
for bakery bread dough. The pan body 12 is fabricated of a liquid-crystal 
polymer, which is a material class generally well known to those having 
ordinary skill in the polymer art. For example, these materials are 
discussed in a survey article entitled Liquid Crystal Polymers: How They 
Process and Why by Duska, which appeared in the December 1986 issue of 
Plastics Engineering at pages 39-42. Such materials have been unexpectedly 
discovered by the present inventor to be particularly well suited to 
bakeware, especially that bakeware designed for commercial baking 
operations. Food products do not adhere to these materials and therefore 
the prior need for greasing or glazing is eliminated. The material can be 
subjected to conventional baking temperatures without any deformation or 
reduction in rigidity. The outer surfaces of pans made from the material 
cool quickly when removed from a high-temperature environment, enabling 
the pans to be almost immediately and easily handled by workers upon 
removal from the oven. The pans also are relatively light-weight and 
tough, further facilitating handling by workers and minimizing damage. 
The pan of the present invention is preferably molded of a liquid-crystal 
polymer sold by Dartco Manufacturing, Inc. of Augusta, GA under the 
trademark XYDAR RC-210. This material is a glass-fiber reinforced 
liquid-crystal polymer having a softening point of 676 degrees Fahrenheit 
and a deformation temperature under load (DTUL) of 655 degrees Fahrenheit 
at 264 psi. 
A presently less preferred but acceptable mterial is the liquid-crystal 
polymer sold by Amoco under the trademark TORLON. However, the TORLON 
material has a five-day cure time and therefore creates significant 
manufacturing difficulties. 
The pan bottom wall 20 is generally planar and rectangular in plan view. As 
illustrated, the bottom 20 is approximately three times as long as it is 
wide. Of course, other shapes and proportions will be readily apparent to 
those having ordinary skill in the art, based upon the article to be 
baked. Two parallel ribs 24A and 24B extend along the underside of the 
bottom proximate one side edge of the bottom 20, while a similar pair of 
ribs 26A and 26B extend along the underside proximate the opposite bottom 
edge. All of the ribs 24 and 26 are generally parallel to one another and 
molded in place. 
As most clearly illustrated in FIGS. 3 and 4, the side walls 22 and end 
walls 23, which are joined at rounded corners 34, are inclined 
approximately 8 degrees from the vertical to facilitate product release. 
The side walls and end walls terminate along an upper peripheral edge 33. 
The side walls 22 and end walls 23 meet in at the gently rounded corners 
34. Similarly the side walls 22 and end walls 23 join the bottom 20 at 
gently rounded corners 36. As presently preferred, the wall thickness 
throughout the pan body 12 is more than 0.060 inch; and the radius of 
corners 34 and 36 is in the range of 0.280 inch. The radiused corners 34 
and 36 facilitate cleaning of the pan since food or other particulate 
matter deposited therein can be relatively easily accessed and removed 
therefrom. 
A strap-retaining structure 40 (FIG. 5) is integrally molded into the pan 
side walls 22 and end walls 23 and is generally uniform in cross section 
around the perimeter of the pan 10. The strap-retaining structure 40 
includes a peripheral stop flange or rib 42 and a peripheral upper edge 
rounded flange or rib 44 smoothly molded into the side and end walls. The 
stop flange 42 and the upper rounded flange 44 are spaced apart vertically 
and an assembly band or strap 46 is formed to fit around the outer surface 
of the upper flange 44 and above the rib 42. The strap is ferrous, or 
other magnetic material and its upper edge is at the level of the upper 
edge of the pan so overhead magnets can be used for handling a pan module 
or assembly of several pans indicated at 48 in FIG. 6. 
This assembly of pans or pan module 48 includes, as shown, five of the pans 
10. The individual pans 10 are spaced apart with spacer blocks shown at 50 
that fit above the rib 42 and which can be made of the same molded 
material as the pans. These blocks can be tubular, if desired to cut down 
on weight and material used, but they are of sufficient length so that 
when they are engaging the outer surface of the adjacent side walls of two 
of the pans placed side by side, the pans are spaced apart with a gap 
shown at 54, the spacer blocks can have suitable retainers to hold them on 
the ribs 42. The rib 44 can also have a recess made with a surface to 
frictionally hold the spacer blocks temporarily. After the strap 46 is 
placed around the assembly and can be fastened with a suitable adjustable 
clamp indicated at 56, at one end of the unit. Additional clamps can be 
used. The clamp is shown schematically, because it can be one that is of 
the type that will take up and apply tension to the strap to hold it 
tightly. 
As can be seen in FIG. 2, the clamp can be a cam lock clamp. One end of 
strap 46 is anchored to a pin 57 on the clamp body 58. The other or free 
end of the strap 46 passes between the base surface 59 of of the clamp 
body and a cam 60 that is pivotal on the body 58 and which wedges the 
strap to lock it after tightening the strap. 
The strap 46 can have a narrower flat section at the clamp and has to be 
made of an FDA approved material. Preferably it is a magnetic material 
that will permit overhead magnets to support the pan assembly or module 48 
for transporting the pans when empty or partially filled. The strap 46 
could also support metal tabs for magnetic lifting at locations spaced 
around the periphery of the pan module. 
The strap 46 can be tightened with a screw tightening clamp such as that 
used with a hose clamp, for example, and there can be two of these clamps, 
one at each end if desired. The space 54 permits air to flow up along all 
of the side walls of the pans during baking, to insure uniform baking and 
adequate operation of the pans. 
The band of course can be any type of band desired, and can be terminated 
so that it only fits around the rib 44 at the upper end of the pans, if 
desired. In other words it does not have to be as wide as that shown in 
FIG. 5, but can be terminated in any desired manner. 
The clamps that are used should be ones that stay out of the way as much as 
possible, in order to avoid interference. A self-contained baking frame 
that supports several pans in a module also could be used. The lower rib 
42 could snap into a receptacle in such self-contained frame to retain the 
pan in place. 
The ferrous (or other magnetic material) strap 14 is secured to the bottom 
of the pan 20, must be of an FDA approved material. The thickness of the 
strap 14 is preferably no greater than the height of the ribs 24 and 26 so 
that the pan rests primarily on the ribs and does not rock upon the strap. 
The strap 14 is retained in position by a pair of countersunk head rivets 
15 which extend through both the strap and the pan bottom 20. 
MANUFACTURE AND USE 
Manufacture of the bread pan 10 begins with the molding of the pan body 12. 
The pan body is formed by injection-molding a liquid-crystal polymer using 
techniques generally well known to those having ordinary skill in the 
polymer and injection-molding arts. Preferably, the specific 
liquid-crystal polymer utilized has a relatively short cure time to 
facilitate the manufacturing process. The rivet holes are drilled in the 
pan bottom preferably using a carbide-tipped drill bit. The strap 14 is 
then secured to the pan bottom by rivets 15 installed through the strap 
and the pan bottom 20. The straps 14, if fastened in two locations must 
have a coefficient of thermal expansion very close to the polymer used for 
molding the pan. Otherwise a separate magnetic material disc can be used 
at each rivet 15. 
Although the pans 10 can be utilized individually in a baking operation, it 
will be preferred in many instances to mount the pans in a module, (FIG. 
6) or a separate baking pan frame. Such mounting facilitates baking 
processes. 
Although the present invention has been described with reference to 
preferred embodiments, workers skilled in the art will recognize that 
changes may be made in form and detail without departing from the spirit 
and scope of the invention.