2. DESCRIPTION OF THE RELATED ART It is well known that certain dangers are inherent in the storage and dispensing of cryogenic materials due to the extreme temperatures involved. For example, the temperature of most cryogenic liquids is often below 350° Fahrenheit. It is common practice to utilize brass hammers for striking the tangs on the trailer fittings when adjusting the associated hose.

This practice places the operator in a very compromising position because of the proximity to the cryogenic liquid. Furthermore, the action of striking the fitting can sometimes create sparks which result in catastrophic consequences for the operator and the surroundings.

There are currently three common types of fittings used on cryogenic trailers. Each fitting is often found on trailers containing common cryogenic liquids such as oxygen, nitrogen, and argon. While each fitting is designed with a four tang construction, the diameters, thicknesses, and widths vary. Heretofore, it has been necessary to use a different wrench with each particular fitting because a wrench designed for use with one fitting would not work with the other two fittings.

While the literature discloses various wrenches and similar devices none are particularly suited for use

with multiple cryogenic fittings. For example, U. S.

Patent No. 150,301 issued on Apr. 28,1874 to Delfer discloses a wrench adapted for use as a wagon-wrench, and other situations where adjustability of the jaws is not required.

U. S. Patent No. 921,290 issued on May 11,1909 to Shelburne discloses a ratchet wrench in which the rotary nut engaging member is open-at one edge, thereby allowing insertion of the nut from the side or the edge. The ratchet wrench also allows the ratchets to be quickly and easily reversed.

U. S. Patent No. 3,447,405 issued on Jun. 3,1969 to Lennon et al. discloses a fitting wrench having a handle with a head positioned at least at one end thereof. The head includes a set of jaws which open laterally of the wrench handle to provide substantially parallel jaw faces.

U. S. Patent No. 4,715,252 issued on Dec. 29,1987 to Pella discloses a valve wrench for safely rotating the wheel of a large valve. The wrench includes an elongated handle, and a wheel grip. The wheel grip further includes a rim grip, and a spoke grip which extends downwardly and inwardly so as to grasp the spoke of the valve wheel.

U. S. Patent No. 5,440,956 issued on Aug. 15,1995 to Johnstun discloses a unidirectional gas valve shutoff tool designed for closing a gas valve having a valve stem with a rectangular profile. The tool has a head and a handle extending from the head to accommodate the application of leverage to the head. A rectangular receptacle is formed in one face of the head and has two diametrically opposed corners for engaging corresponding corners of the valve stem in order for the tool to rotate the gas valve. The head is angularly offset in order to provide an ergonomically acceptable configuration for the tool.

French Patent No. 1-, 519,120 issued on Mar. 1968 discloses a key for the attachment of the nut of a valve assembly onto a butane gas bottle used with heating installations and domestic kitchens.

Great Britain Patent No. 2,298 issued on Jan. 1897 discloses an improved key for opening the caps of petrol and similar tins. The key is formed of a cylindrical shape with an internal diameter of approximately the same size as the external diameter of the cap, with two segmental shaped apertures formed in the top of the cylinder to fit over two projections on the cap, and with the front of the cylindrical portion of the key having a greater depth than the back where the handle is attached.

U. K. Patent Application No. 2,018,179 published on Oct. 1979 discloses a spanner made of fiber-reinforced resin in which carbon or boron fiber reinforcement is used to provide strength and reduced weight while providing a spark-proof spanner.

None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus a cryogenic wrench solving the aforementioned problems is desired.

SUMMARY OF THE INVENTION Accordingly, it is a principal object of the invention to provide a wrench capable of engaging the fittings of cryogenic trailers.

It is another object of the invention to provide a wrench capable of engaging a variety of different fittings of cryogenic trailers.

It is an object of the invention to provide improved elements and arrangements thereof in a three in one cryogenic wrench for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.

In accordance with the objects of the invention, a three in one cryogenic wrench is provided for engaging the fitting on the couplings of cryogenic trailers.

The three in one cryogenic wrench includes a handle and a head integrally formed from the handle. The head contains a central aperture and terminates in an open end so as to define a pair of jaws. Each jaw contains a recess on its interior surface. The head also contains a third recess which is positioned directly opposite of the open end. The three in one cryogenic wrench is carefully designed such that it is capable of engaging the three couplings most commonly found on cryogenic trailers. In preferred embodiments of the invention, the three in one cryogenic wrench is constructed from non-striking materials in order prevent accidental sparking.

These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of a cryogenic wrench in accordance with the present invention.

Fig. 2 is a top plan view of the cryogenic wrench.

Similar reference characters denote corresponding features consistently throughout the attached drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to Figs. 1 and 2 of the drawings, a three in one cryogenic wrench is shown and generally indicated by the numeral 10. The three in one cryogenic wrench is particularly suited for engaging the fitting found on the couplings of cryogenic trailers. As seen in Figs. 1 and 2, the three in one

cryogenic wrench 10 includes a handle 12 having a blunt end 26, and a head 14 integrally formed on the opposite end of the handle 12. The head 14 contains a central aperture and terminates in an open end which is generally indicated by the numeral 20.

The head 14 is designed such that a pair of jaws 16 is defined in conjunction with the open end 20. Each jaw 16 contains a recess 18 on its interior surface.

As seen in Fig. 2, the recesses 18 on the jaws 16 are positioned directly opposite of one another. The head 14 also contains a recess 18 which is positioned directly opposite of the open end 20. In preferred embodiments of the invention, the recesses 18 may be equally sized and dimensioned.

Referring particularly to Fig. 2, the handle 12 includes opposing surfaces 22 (only one shown), and opposing sides 24. The opposing surfaces 22 are sloped toward each other along the length of the handle 12 away from head 14, and the opposite sides are tapered other along the length of the handle away from head 14. The sloped opposing surfaces 22 and tapered opposing sides 24 converge at the blunt end 26, providing the same with reduced thickness and width in comparison to the portion of the handle adjacent to the head 14. The taper serves to alleviate some of the problems encountered during removal of fittings on the trailer. For example, the space available to maneuver a wrench is often restrictive. Thus, by tapering the handle 12 of the three in one cryogenic wrench, the travel distance is increased and the risk of accidentally striking any adjacent fittings is minimized.

The three in one cryogenic wrench 10 is carefully designed such that it is capable of engaging the three different couplings most commonly found on cryogenic trailers. These couplings are often found on oxygen, nitrogen, and argon trailers. In preferred

embodiments of the invention, the three in one cryogenic wrench 10 is constructed from non-striking materials in order to prevent accidental sparking.

Suitable non-striking materials include aluminum and aluminum containing alloys of the type well known in the art. Furthermore, the length of the handle 12 may be increased to provide benefits to the operator. For example, extending the length of the handle 12 provides a certain mechanical advantage in the application of torque to the fitting, and eliminates the need to use a brass hammer on the fitting.

Furthermore the operator's hand is placed further away from the fitting in order to minimize the potential effects of an accidental discharge when the hoses are uncoupled.

It is to be understood that the present invention is not limited to the embodiment described above, but encompasses any and all embodiments within the scope of the following claims: