W. C. Snell
Patented Sept. 16, 1953
The present invention relates generally to blowtorches and more particularly to a specialized type of blowtorch useful in numerous household repairing operations where relatively intense localized heat is required for short periods of time, such for example as in the mending of broken chinaware.
Blowtorches of various kinds, and the basic principles of operation common to all of them, are of course quite old and well known. The present invention necessarily functions in accordance with familiar basic principles insofar as concerns the vaporization of a liquid fuel, the generation of a jet or blast therefrom, and the igniting thereof. However, the device differs from prior blowtorches in a number of respects. Thus, whereas most of the blowtorches of the prior art are relatively costly and elaborate instrumentalities, designed for general or particular technological use, mainly by skilled artisans, the subject of the present invention fills the need for a small, highly simplified device that can be manufactured at very low cost for sale to the general public in the form of a boxed kit, or with its several parts attached to a merchandising card, at a price low enough to justify purchase for a single use although the device is inherently durable enough to last through many uses.
A primary object of the invention is therefore to provide an inexpensive blowtorch device that can be safely and readily used by an inexperienced person, that can be easily adjusted to direct a fine jet of flame accurately on to small or narrow surfaces that require heating, and that will maintain a constant jet, on a single filling or fuel, for a period of time ample to complete any ordinary blowtorch operation.
Another object is to provide a blowtorch head in the form of a filled casing having a jet or blast aperture equipped with a mounting which includes an integral base on which the object to be heated can be positioned, with the head and its issuing jet fixed in stable relation to the object, so that the operator's hands are left free to perform such functions as, for example, the application of cement to the object, or to press the parted surface together, or for other purposes.
Other objects and advantages of the invention will be more evident to those skilled in the are from the following description of a preferred embodiment which is illustrated by the accompanying drawing, in which
Figure 1 is a plan view of a preferred embodiment of the invention in the flat form in which it is manufactured and sold:
Fig. 2 is a side elevational view of the device shown in use in connection with the mending of a broken china cup:
Fig. 3 is an end elevational view of the device shown in the operative disposition of Fig. 2; and
Fig. 4 is an enlarged detail view of the head or casing taken on the line 4-4 of Fig. 3.
But thes figures and the following description are made only for the purposes of disclosure of the invention in a preferred form of embodiment that has been reduced to actual practice and found entirely satisfactory. As will be seen, the details of eh invention are capable of being altered and varied within wide limits within the spirit of the invention and the scope of the broader of the appended claims.
In the drawing the reference numeral 1 designates generally the head of the blowtorch which comprises a casing of preferably ovate shape fully enclosing a body 2 of absorbent filling material. The casing in best made of thin, heat-refractory sheet material such as metal foil, e.g., aluminum foil of a thickness of 0.0015 inch, folded and crimped on itself so as to have a maximum internal length of about one and one-quarter inch and a maximum internal diameter of about one-half inch, although these dimensions and proportions are not critical and may be varied. The filling material is conveniently raw cotton, which is of course very inexpensive, although other preferably fibrous materials may be substituted. The filling is packed loosely in the casing and is fully and entirely covered thereby except for two apertures which will now be described.
In what may be regarded as the upper surface of the head 1, near the relatively pointed end thereof which may be considered to be the front or nose of the head, the casing material is punctured to form the aperture 3, and a similar aperture 4 is formed nearby, as best shown in Fig. 4. The aperture 3 is formed in a direction straight through the casing material, and the aperture 4 is directed angularly through the material, being generally parallel to the longitudinal axis of he head and located in the upper portion of the nose, as clearly appears in Fig. 4. The best sizes for the apertures are approximately 0.0312 inch for he aperture 3, and 0.0230 inch for the aperture 4. They may be directed at an angle of almost ninety degrees to each other, as shown, and their outer edges may be set approximately one-quarter inch apart.
A body of cotton of approximately four grains weight comprises a suitable quantity for a casing of the suggested size.
In assembly, the cotton may first be shaped to the approximated shape and proportions intended for the finished head. A flat disc of foil is then fashioned into cup shaped having approximately the curvature of the rear end of the head to provide a sort of tube, the cotton body is placed in the cup-like bottom of the tube, and the margins of the foil sheet are then brought together and crimped on each other to form the nose of the casing. Excess areas of foil are trimmed away and the whole assembly is then shaped to the ovate form shown in the drawing, with the foil at the crimped zones in the nose being somewhat thicker than in the single ply areas to the rear of the nose.
The apertures are then made by puncturing with any pin or needle of suitable size. The aperture 4 is left entirely open, but a small portion of the cotton filling is pulled through the aperture 3 to serve as a wick 5. This operation can easily be performed by using a hooked needle which is inserted into the opening 3, engaged with some of the cotton fibers and then pulled back out through the aperture to leave those fiber gilling the aperture, in the condition shown in Fig. 4.
The aperture 4 functions as the blow hole or blast passageway while, as has been explained, the aperture 3 is the wick opening.
When the head is submerged for a few moments in a suitable liquid fuel, such as methyl or denatured alcohol, the liquid quickly enters the casing through the aperture 3, being copiously absorbed by the filling 2, while the displaced air bubbles out though the blow hole 4. If then a lighted match be promptly applied to the head, the fuel remaining on the head surface will be ignited and will burn momentarily. When the surface coating of fuel is all consumed the flame will die out, but the wick 5 will continue to support a flame. The heat generated by the initial burning of the surface fuel will vaporize some of the fuel in the head and the vapor will issue as a jet from the open aperture 4. Vaporization will be maintained, as long as the fuel absorbed by the filling 2 lasts, by the heat developed b the burning wick 5, and the amount of this heat applied to the head, and consequently the rate of vaporization, can be regulated by turning the head more or less about its longitudinal axis to position the wpick flame anywhere between the uppermost position shown in the drawings or some lower position in which the flame will play over more of the surface of the head. Thus the length of the blast or jet, and consequently the rate of hear generation, can be controlled.
The flame supported by the wick 5 serves also the purpose of insuring constant ignition of the jet or blast. Its proximity to the orifice from which the vapor issues will promptly re-ignite the vapor stream if for any reason the jet should become extinguished.
In order to mount the head for use in a stable position leaving the operator's hands entirely free, the support shown in Figs. 1, 2 and 3 is provided. This comprises a length of relatively stiff but pliable wire 6 having one end portion wound in a plurality of turns around the head 1 as shown at 7 and having its opposite end formed in generally ring shape, preferably but not necessarily substantially round, continuous and closed, as shown at 8. A disc or foil or other sheet material 9 may be disposed within the ringed end 8 of the wire and have its margins folded around the wire, so as to form a flat base on which an object to be heated by the blowtorch can be positioned, in the manner of the china cup 10 shown in Fig. 2.
It will be evident that the pliability of the wire 6 permits ready bending of the wire, as between the full and broken line positions shown in Fig. 2, so that the head can be lifted and held briefly in an open jar of fuel and then can be turned down to the broken line position and ignited so that the jet issuing from the blow hole 4 will be directed where desired, as for example at the broken area 11 of the object 10, and will remain in that position while the operator uses his hands for such purposes as manipulating the object, applying the cement thereto, etc.
It will be evident that the turns 7 of the wire 6, which extend on both sides of the zone of maximum diameter of the head 1, securely hold the head, and that the broad area of the base 9 will effectively prevent upsetting the device even when the base is not held down by the weight of an object 10.
The device is manifestly extremely inexpensive to make. It can be boxed or carded as part of a kit including such adjuncts as a jar of fuel, a tube of cement, etc., and can be sold at a price low enough to justify purchase for a single use, although of course the device is durable enough to be reused many times. The invention thus supplies a long felt need for which the more elaborate and costly blowtorches of the prior art are not adapted to be used.
1. A blowtorch comprising a single casing of metallic foil provided with a single pair of substantially right-angularly related and closely juxtaposed apertures having axes intersecting within the casing, and a body of liquid-fuel-absorbent filling material fully enclosed by the casing, a portion of the filling material protruding through one of said apertures to serve as an igniting and heating wick and the other aperture being open and unfilled to serve as a blast passageway for fuel vaporized within the casing by heat from the wick.
2. A blowtorch comprising a sheet of metallic foil curved and folded to form a single casing generally oval in longitudinal cross section and provided in one end portion with a single pair of apertures, the axis of one aperture being substantially parallel to the longitudinal axis of the casing and the axis of the other being substantially parallel to the transverse axis of the casing, and a body of liquid-fuel-absorbent filling material fully enclosed by the casing, a portion of the filling material protruding through the second named aperture to serve as an igniting and heating wick and the first named aperture being open and unfilled to serve as a blast passageway for fuel vaporized within the casing by heat from the wick.
3. A blowtorch comprising a casing of substantially ovate shape having an absorbent fill and provided at one end portion with a single protruding wick and a single open blast passageway closely juxtaposed and having their axes intersecting within the casing, and a wire support having one end portion formed in generally ring shape to serve as a base and having its other end portion wrapped around the casing to hold the casing rotatably captive therein.
4. A blowtorch comprising a metallic foil casing of substantially ovate shape having an absorbent fill and provided at one end portion with a single protruding wick and a single open blast passageway closely juxtaposed and having their axes intersecting within the casing, and a wire support having one end portion wrapped around the casing to hold the casing rotatably captive therein and having its other end portion formed in generally ring shaped and having an area of sheet material secured in said ring shaped portion to serve as a base for mounting an object to be heated.