Cooking over an open fire is one of the oldest ways to cook. Because the temperature of a fire can vary significantly depending on the size of the fire and the fuel used, many methods have been devised to support the cooking surface above the flames. While a fireplace provides a permanent structure onto which cooking apparatus can be affixed, no such structure is available for a campfire made in a firepit. 
Cooking in primitive conditions has its own requirements. For example, campfire cooking requires that a grill or other cooking surface be close to the fire. This either requires a pan or griddle to rest on a rock near the fire or requires allowing a large bed of coals to accumulate so that a cooking implement can be set directly into the coals. In order to cook over an open flame, it is necessary to have the cooking surface suspended by some method over the flame so as to take advantage of the hottest part of the fire. In addition, while apparatus, such as tripods, for suspending cooking utensils over a fire are not new, their use has certain requirements. For example, the cooking apparatus needs to be fireproof. It is also expected that most parts of the apparatus will become too hot to touch directly. In addition, because an open fire is, almost by definition, not a constant heat source, the user will need some way to adjust the cooking heat resulting from the flame. While one solution would be to disperse the fuel when the fire gets too hot, such a solution would require re-kindling of the fire should the user wish more heat. 
Other solutions have been attempted. For example, U.S. Pat. No. 366,833 to Hipwell describes a tripod support for cooking over an open fire that includes a three  legged stand with a planar cooking surface suspended underneath the stand by use of three separate chains. 
U.S. Pat. No. 4,024,851 to Boda describes a tripod for cooking in which one of the legs is larger and designed to receive all other components of the device. The tripod includes a square grill suspended at the corners by four cables. The cables are attached to one end of a grill-hanging cable. The second end of the hanging cable terminates in a cable hook. The large leg includes a guide for the grill-hanging cable. The cable hook fits into receptacles along the length of the large leg. The height of the grill is then adjusted by moving the cable hook up and down the length of the large leg. 
U.S. Pat. No. 4,146,010 to Manska describes an outdoor grill tripod. The tripod includes three legs connected at the apex. A planar grilling surface is suspended from three chains, each chain individually attached to one of the legs by a suspension lock. Each of the chains is separately adjustable by sliding the suspension lock up and down the leg. 
U.S. Pat. No. 4,732,138 to Vos describes a campfire cooker which includes a tripod from which is supported at least one cooking surface. Further, the device includes a firebox, which may be on wheels and which has receptacles for accepting the ends of the tripod legs. The Vos device allows the suspension of two different cooking surfaces by two different mechanisms. Vos describes a lower grill suspended by three chains, each chain adjustably connected to a leg, similar to Manska. Vos also describes an upper cooking surface in which the grill is suspended by three individual support chains, spaced equidistant around the circular grill periphery. The support chains are connected together at a suspension ring, which is further connected to a fourth support chain. The fourth support chain passes up and through a second suspension ring, which is suspended beneath an apical locking plate, which joins the legs. The chain can then be fixed on one of the legs by use of a locking bracket. Thus, as in Boda, the height of the second grill above the fire can be adjusted by moving a single locking bracket up and down the leg of the tripod.  
U.S. Pat. No. 4,120,280 to Iverson describes a portable tripod for use in cooking over an open fire. The tripod has telescoping legs connected at an apical plate. A grill is connected to one end of three short chains spaced equidistantly around the grill. The chains are connected at their other end to a support chain. As in Vos, the support chain passes up through a suspension ring attached to the apical plate and is fixed along one leg by the use of a slide lock. By moving the slide lock up and down the leg, the height of the grill over the fire is adjusted. 
While the cooking devices described above provide a platform for cooking over an open fire, they lack the flexibility and safety that is desirable when cooking over open flames. Specifically, all of the tripods discussed provide a means of adjusting the cooking surface by moving a bracket up or down the length of a leg of the apparatus. This method of adjustment has at least two major hazards. First, because any object suspended over a hot fire will itself become hot, there is a real danger of burns should an attempt be made to adjust the grill after the fire becomes hot. Second, because the objects on the grill are suspended from the tripod, attempting to move the cooking surface with heavy objects on it, by adjusting a hot slide lock along the leg, risks upsetting the entire apparatus. This situation could result in severe injuries. 
Therefore, there is a need for an apparatus that allows cooking over an open fire that is safe and easy to use. Preferably, the apparatus can be used while cooking is in progress to obtain an optimum height for the cooking surface as the fire burns, without further increasing the risk or adding danger to the experience of campfire cooking. 