Portable campfire grill

A portable campfire grill employing three identical elongate members constructed of steel or like heat resistant material. Each of the elongate members has a pair of slots, one slot being formed adjacent each end and the respective slots being oriented in opposite directions. The slots have a depth half the width of the member so that when the elongate members are engaged by interengagement at the slots, the opposite surfaces of the elongate members are in coplanar relation thereby forming a triangular shaped grill structure having a flat surface. The slots have a dimension in a direction longitudinally of the members such that the members must be stressed to effect such interengagement so that the triangular structure formed by assembling the three members is retained in assembled, operative condition.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a portable campfire grill and more particularly 
to a portable campfire grill that is capable of disassembly so as to 
afford transportation thereof in a compact form such as is desirable in 
backpacking. 
2. Description of the Prior Art 
As far as is known, backpackers have either transported grates formed of a 
plurality of cross wires supported in a rigid configuration or have relied 
on hooks or the like to support pots over a campfire. A grate is a 
relatively large article and difficult to pack in a backpack of 
appropriate size. Campfire cooking without a grate of any kind is 
extremely inconvenient and difficult. 
SUMMARY OF THE INVENTION 
In its preferred form the present invention is embodied in three identical 
elongate steel members having a length of approximately 20 inches. The 
members have a generally rectangular cross-section and have oppositely 
facing notches formed adjacent the respective ends thereof. The notches 
are so proportioned with respect to the thickness of the elongate members 
that by interengaging the members adjacent the notches a triangular grill 
is formed. The notches are proportioned so that in order to interengage 
the members it is necessary to stress the members slightly wherefore a 
frictional force between the contacting portions of the respective 
interengaged members retains the grill in an assembled condition. 
An object of the invention is to provide a simple campfire grill capable of 
disassembly so as to facilitate transportation of the grill in a backpack. 
This object is achieved by providing three identical elongate members 
which occupy but little space in a backpack and which through the above 
mentioned slot arrangement and configuration can be assembled into a 
triangular grill that is suitable for being supported on rocks or the like 
disposed around a campfire. 
Another object of the present invention is to provide such a campfire grill 
wherein the grill will remain in an assembled condition until purposely 
disassembled. This object is achieved by so proportioning the slots that 
the members must be stressed in order to assemble them into the triangular 
configuration. Achievement of the object stated above permits the grill to 
be placed over a campfire or removed from a campfire with one hand and 
with great facility. 
Still another object of the invention is to provide a campfire grill of the 
type described above in which all members, when in an assembled condition, 
are in coplanar relationship. Achievement of this object is important in 
that pots can be supported at the intersections or apices of the 
respective members and is accomplished because the above mentioned slot 
are formed with a depth equal to one-half of the width of the elongate 
members so that when the members are interengaged with one another at the 
slots the advantageous coplanar relationship is achieved. 
Yet another object is to provide a portable campfire grill that is 
extremely stable when in use. This object is achieved by forming the grill 
in a triangular shape which can be supported over a campfire by 
strategically placed rocks or the like. 
The foregoing together with other objects, features and advantages will be 
more apparent after referring to the following specification and the 
accompanying drawing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring more particularly to the drawing, reference numerals 12, 14 and 
16 indicate substantially identical elongate members formed according to 
the invention. Because the members are substantially identical, a detailed 
description of one, having reference to FIGS. 1 and 2, will suffice as a 
description of all. Elongate member 12, as can be seen in FIG. 2, is of 
rectangular cross-section having a thickness dimension 18 and a width 
dimension 20. At spaced apart locations along the elongate member 12, 
preferably adjacent opposite ends thereof, are slots 22 and 24. As can be 
seen in FIG. 1, slots 22 and 24 extend to opposite edges of the member for 
a purpose which will be made clear subsequently. The slots have a depth, 
as seen in FIG. 2, equal to one-half the width dimension 20 of the 
elongate member. When one elongate member is engaged with another by 
interengaging notch 22 of one member with notch 24 of the other member, 
the edges of the respective members are coplanar because of the fact that 
the depth of both slots 22 and 24 is equal to one-half the width of the 
members. 
The axial extent of each of the slots is established so that it is 
necessary slightly to stress the respective elongate members when they are 
assembled, thereby causing a frictional force between the interengaged 
members which retains the members into the triangular configuration shown 
in FIG. 3. The preferred axial extent of the slots can be appreciated by 
reference to FIG. 4. FIG. 4, although it exemplifies the case where each 
of three members 12, 14 and 16 is identical, has more general application 
because the same factors apply where the elongate members are not 
identical and are employed to form a non-equilateral triangle. The 
longitudinal dimension of the slot must be greater than the thickness 18 
of the elongate member to afford introduction of the member into the slot. 
The maximum dimension is determined by certain trigonometric relationships 
and by the elasticity of the material of which the elongate members are 
constructed. The theoretical maximum longitudinal dimension of slot 24 is 
shown in FIG. 4 for an included angle A that approaches 60.degree. as 
would be the case in an equilateral triangular configuration. The 
longitudinal dimension can be considered as having two components, one 
designated by the solid line x and the other designated by the broken line 
y. The longitudinal dimension of the slot is x+y. If A is 60.degree. then 
angle A' will also be 60.degree. wherefore the following equation for x 
can be derived: 
EQU x=T/tan 60.degree.=T/.sqroot.3, 
wherein T is thickness dimension 18. With respect to the distance y, the 
angle A' is assumed to be 60.degree. wherefore the distance of y is 
represented by the following equation: 
EQU y=T/cos 60.degree.=T/.sqroot.3/2. 
Accordingly the longitudinal dimension of the 
slot=x+y=T/.sqroot.3+T.sqroot.3/2=.sqroot.3.times.T=1.7321 T. 
A slot having the above longitudinal dimension permits interengagement of 
two of the elongate members in an equilateral configuration without 
stressing the material of which the elongate members are formed. Thus, in 
order to insure a degree of stress in the members, it is essential that 
the longitudinal dimension of the slots be less than the quantity 
.sqroot.3.times.T to assure that the members will be stressed when in the 
assembled condition so as to assure a frictional force that maintains the 
elongate members in an assembled condition. The specific longitudinal 
dimension of the slots between a minimum, equal to the width of the 
members, and a maximum, equal to less than .sqroot.3 T, will be determined 
by the elasticity of the material of which the elongate members are 
constructed, because it is essential that the longitudinal dimension of 
the slot be such that the elastic limit of the material is not exceeded 
when the members are in an assembled condition. In one structure designed 
according to the present invention elongate members 12, 14 and 16 are 
formed of steel stock having a length of about 20 inches, a thickness of 
1/8 inch and a width of 3/8 inch. In such design slots 22 and 24 of the 
respective members have a longitudinal extent of 3/16 inch and a depth of 
3/16 inch. Such exemplary structure, when assembled, defines an interior 
angle at the apices of the triangular configuration equal to approximately 
62.degree., indicating that each of the elongate members intermediate the 
slots is slightly bowed to a degree well within the elastic limit of the 
material. 
It will be noted from FIGS. 1 and 3 that slots 22 and 24 are not uniformly 
spaced from the respective ends of the elongate members of which they are 
a part. As seen in FIG. 3 such non-uniformity forms at each apex a 
relatively long leg designated respectively at 12', 14' and 16'. Such legs 
function to support the apices of the assembled structure, such as by 
means of a rock R at a point spaced from the apex or intersection of the 
respective corners of the structure. Of course this mode is possible only 
if slot 24 (the slot adjacent the long leg) faces upward at all corners. 
The function of the legs is to permit fire to exist under the respective 
corners or apices of the triangular configuration so as to support a pot 
at such corner above the fire and without interference with rock R or 
other means employed to space the grill above the fire. In the exemplary 
embodiment referred to above long legs 12', 14' and 16' each have a length 
of about 6 inches as compared to the distance between slot 22 and the end 
to which it is adjacent of about 31/2 inches. 
Thus it will be seen that the present invention provides a campfire grill 
that is highly portable in that it comprises three long thin members, but 
which can be quickly assembled and installed at a campsite. When placed 
over a fire the grill is rigid, a characteristic arising from its 
triangular construction and from the fact that the elongate members must 
be slightly stressed in order to effect and retain assembly of the grill. 
The equilateral form, as described hereinabove and shown in the drawing, 
has the advantage of employing three identical members. It is within the 
invention, however, to provide three members of unequal length thereby 
forming a grill of isosceles or scalene shape. 
Although one embodiment has been shown and described, it will be obvious 
that other adaptations and modifications can be made without departing 
from the true spirit and scope of the invention.