U.S. patent number 3,890,952 [Application Number 05/406,345] was granted by the patent office on 1975-06-24 for portable camping stove.
Invention is credited to Mervin A. Hamre.
United States Patent |
3,890,952 |
Hamre |
June 24, 1975 |
Portable camping stove
Abstract
A camping stove incorporating a pair of tubular chambers each
chamber having an aperture in the side. Each tube has a concentric
tightly fitting secondary tubular chamber inside, which secondary
tube contains fuel impregnated fibrous packing material. The
secondary tubes also have apertures in the side which can be moved
into alignment with the burner apertures in the outside tubes so as
to permit ignition of the fuel therein. The tubes are mounted in a
box with a grill type structure. The box has a foldable top with
folding wind shields thereon and legs that fold around to lock the
top closed so as to permit the entire stove to close up into a
compact easily portable box.
Inventors: |
Hamre; Mervin A. (St. Paul,
MN) |
Family
ID: |
23607581 |
Appl.
No.: |
05/406,345 |
Filed: |
October 15, 1973 |
Current U.S.
Class: |
126/45;
126/38 |
Current CPC
Class: |
F24C
5/06 (20130101); F24C 5/20 (20130101); F23D
2900/05001 (20130101) |
Current International
Class: |
F24C
5/00 (20060101); F24C 5/06 (20060101); F24C
5/20 (20060101); F24c 005/06 () |
Field of
Search: |
;126/45,38,43
;431/326,315 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: O'Dea; William F.
Assistant Examiner: Joyce; Harold
Attorney, Agent or Firm: Jacobson and Johnson
Claims
I claim:
1. A portable stove comprising:
a housing having side walls;
a plurality of burner assemblies mounted to said housing between
two side walls, each of said burner assemblies comprising a first
cylindrical chamber having first aperture means in one side, a
second cylindrical chamber rotationally and axially movably mounted
inside said first chamber and in intimate sealing contact
therewith, said second chamber having second aperture means in one
side;
a handle extending outside a side wall connected to an end of said
second chamber so as to allow said second chamber to be moved to
various positions having varying degrees of overlap between said
aperture means; and
a fuel absorbent packing material in said second chamber adapted to
be saturated with inflammable fuel, which fuel can be burned when
exposed to the air by a suitable alignment of said aperture
means.
2. The apparatus of claim 1 in which said aperture means comprise
generally rectangular openings in the walls of said cylindrical
tubes.
3. The apparatus of claim 1 in which said aperture means comprise a
plurality of openings in the walls of each tube.
4. The apparatus of claim 3 further including a grill mounted on
said housing over said burner assemblies.
5. The apparatus of claim 4 further including: a folding top,
folding side wind shields and folding legs attached to said
housing.
6. The apparatus of claim 5 in which said wind shields fold against
said top and said top folds down to close said housing and said
legs fold around said housing to hold said top closed.
Description
BACKGROUND OF THE INVENTION
Small portable camping stoves which burn a liquid fuel such as
gasoline or alcohol are well known in the prior art. Generally,
these stoves comprise a fuel tank which must be pressurized by
hand. The pressurized fuel is then forced out through an adjustable
valve and burner arrangement. These prior art stoves are expensive
and complicated. They must be periodically pumped to maintain a
sufficient pressure in the fuel tank. Because they use a
pressurized system, a number of pressure fittings are required
along with a fairly sophisticated pumping apparatus. Since the
pressure varies, the size of the flame varies and therefore the
valve controlling the fuel flow must continually be adjusted. In a
camping environment, it is difficult enough to prepare a meal
without the added burden of continually adjusting and pumping the
stove to keep it operating properly. Other problems include leaks
that develop in the pressurized fuel tanks during storage
especially if there is some residual pressure from the previous
operation. It would be more desirable if a compact stove could be
provided which would require no pumping, burn a steady, even flame
without adjustment and yet still permit easy refueling and provide
an easily adjustable flame. My invention accomplishes these ends as
described hereinafter.
SUMMARY OF THE INVENTION
Briefly, my invention proposes a new type of camping stove having a
compact folding housing and a unique burner assembly. The burner
assembly comprises two concentric tubes which are slidable, one
within the other but yet are sized so that they fit snugly together
providing a good seal therebetween. The inside tube is filled with
a nonflammable, fibrous packing material such as asbestos, which
material can be saturated with a suitable fuel such as alcohol. One
of the tubes is rotated or slid axially with respect to the other
tube by means of a handle fastened to it so as to bring an aperture
in the inside tube into alignment with an aperture in the outside
tube. The amount of overlap between the two apertures determines
how much of the fuel soaked packing material is exposed to the
outside air and therefore the size of the flame. The fuel burns
steadily without the need of any adjustments or attention, flowing
automatically from the fibrous packing material. Since the flame
size is determined by the area of the opening, a steady,
controllable flame may be produced of any desired size merely by
changing the opening size through sliding or rotating the tube.
Refueling is easy. The holes are simply moved into alignment and
fuel is poured in until it saturates the packing material. No
pressurization is involved and no pump is necessary. No pressure
fitting or special valves are necessary to control the fuel flow.
In the alternative, the inside tube may be completely withdrawn
from the outside tube and refueled from one end.
The flame is easily extinguished simply by closing the aperture,
again by sliding or rotating the tube. It has been found that the
tubes remain cool and can even be touched immediately after the
flame ceases. This is advantageous in that the fire and burn hazard
from hot metal is reduced. The cool condition is believed to be a
consequence of the continual evaporation of fuel in the inside tube
as it is drawn off for burning.
Any number of these paired concentric tube burners may be mounted
in a housing to provide a stove. In the preferred embodiment, two
sets of concentric tubes are shown mounted in a housing of special
design. The special housing comprises a metal box having foldable
legs, top, and wind shielding sides to insure a well protected
environment for the burners. The legs, top and sides all pivot
together to provide a compact carrying case for the stove.
The shape and arrangement of the apertures in the inside and
outside tubes may be varied widely to provide different burner
arrangements with different operational characteristics. These will
be discussed in greater detail below.
It may therefore be seen that it is an object of my invention to
provide an improved camping stove. It is a further object to
provide a compact folding stove having maintenance free burners
which are easy to adjust and refuel. Further objects and advantages
will become apparent upon consideration of the following
description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the camp stove of my invention
showing the stove in an open, operational condition;
FIG. 2 shows my camp stove folded down for easy transport;
FIG. 3 is a partially cutaway side view of one of the burners in
the preferred embodiment of my stove;
FIGS. 4 and 5 show two possible variations of the preferred
embodiment of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 1 and 2, a portable camp stove is shown, in open
and folded conditions, comprising a generally rectangular metal box
10 with a cover 12 hinged thereon. Cover 12 pivots about two small
tabs 13 which rest in small holes in the corner of box 10. A pair
of wind protectors or shields 11 are pivoted on cover 12. Wind
shields 11 have small tabs 14 which extend through holes in four
tabs 15. Tabs 15 are cut out of top 12 and bent into the position
shown in FIG. 1. The left wind shield in FIG. 1 is cut away to
better show the contents of box 10 but both shields 11 rest on
small pins 17 mounted in slots 19 in box 10. It is apparent in FIG.
1 that the whole box can be easily folded together into the compact
portable configuration of FIG. 2. Pins 17 are rotated 90.degree. to
drop into box 10, the wind shields 11 are rotated to lie flat
against the inside surface of top 12, and top 12 is then closed and
held in place by rotating a pair of legs 23 in their holes 25 from
the position of FIG. 1 to the position of FIG. 2. Legs 23 are held
in the position of FIG. 2 by small risers or bumps 29 formed in the
front of box 10. A handle 27 may be formed from wire and mounted
through two suitable holes in the front of box 10.
Returning to FIG. 1, mounted over the top of box 10 is a grill 16
upon which various utensils may be rested above the burners. The
burner assembly comprises a pair of tubes 18 mounted in box 10.
Tubes 18 are described in greater detail with respect to the
cutaway side view of FIG. 3.
In FIG. 3, it may be seen that each outside tube 18 is mounted
between the walls of box 10. Inside of each tube 18 is a
concentric, snugly fitting tube 20. A generally rectangular hole 22
in tube 18 faces upwards in box 10 to comprise the burner opening.
Tube 20 also has a rectangular hole 24. As described earlier, the
inside tube 20 is filled with a fibrous packing material 26 which
may comprise asbestos fiber or any other suitable nonflammable
material. The packing material 26 is saturated with a suitable fuel
such as alcohol. During storage, tube 20 is rotated to a position
at which holes 22 and 24 do not overlap at all. Tube 20 is fitted
snugly in tube 18 so that a seal is produced and no leakage
results. Since the liquid fuel is held in place by the packing
material, it is only necessary to prevent leakage of vapor. Thus,
the snug fit provides a sufficient restriction on normal convective
air flow to insure that no leakage results.
Tube 20 is closed at the righthand end and welded to a shaft 28
which, in turn, is connected to a handle 30. With the use of handle
30, tube 20 can be rotated so as to overlap apertures 22 and 24.
This action exposes the alcohol saturated packing material which
can then be ignited. The fuel burns over the area of aperture 24
which is exposed by aperture 22. Additional rotation of handle 30
exposes greater amounts of aperture 24 allowing a larger flame. To
extinguish the flame, handle 30 is simply rotated so as to roll
aperture 24 out of alignment with aperture 22 thus cutting off the
oxygen supply, effectively snuffing the flame, and once again
sealing in the fuel material. As mentioned, the tubes 18 and 20
remain cool to the touch during burning thus reducing the hazard of
burns and fires.
In FIG. 4, it may be seen that another method of operating the
stove involves sliding tube 20 axially along tube 18 so as to move
aperture 24 to a position beyond aperture 22. Progressively larger
flames can be produced by pushing tube 20 inward thus overlapping
more and more the ends of apertures 22 and 24. If desired, tube 20
can be completely removed from tube 18. Since tube 20 is open at
the left end, it can be readily refueled or repacked, if necessary,
from the exposed end. This easy disassembly also permits the stove
and burner apparatus to be quickly and easily cleaned. This is an
especially desirable feature when food spills on the burners during
cooking and the like.
It is readily apparent that many different configurations of
apertures may be utilized to produce different types of burners.
For example, in FIG. 5 an outside tube 32 is shown having three
holes 34 therein. The inside tube is accordingly provided with
three holes 36 which can be rotated into alignment with holes 34 by
means of a handle 38.
Yet another embodiment may involve a long, narrow slot rather than
discrete holes. The holes, of course, need not be rectangular but
could be oval or round or even triangular shaped so that a small
corner is opened initially for a very small flame and then, as the
rotation of the tubes relative to each other is increased, the hole
size is increased quickly to provide a large flame.
Another possible arrangement could utilize a spiral groove in one
or more of the tubes so as to provide a changing axial location of
the overlapping portion of the slots so that the flame may be
positioned anywhere along the length of tube 18. Still another
arrangement could use non-cylindrical tubes having rectangular
cross-sections, for example. It is also possible to produce burners
wherein the inside tube would be fixed to the housing and the
outside tube caused to slide along or rotate about the inside tube.
Numerous other arrangements will be obvious to those having
ordinary skill in the art and therefore I intend to be limited only
by the appended claims.
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