US 3913482 A
A manually-operated, projectile-firing device includes a charge comprising a first-stage charge portion for imparting an initial movement to the projectile, and a final-stage charge portion arranged to be detonated subsequent to the first-stage charge portion and subsequent to the occurrence of initial projectile movement. The final-stage charge portion is arranged to burn more slowly than the initial-stage charge portion as it accelerates the projectile to discharge velocity.
Description (OCR text may contain errors)
United States Patent Schiessl et al.
[ Oct. 21, 1975 MANUALLY-OPERATED PROJECTlLE-LAUNCHING DEVICES Inventors: Alois Schiessl, Bad Reichenhall;
Paul Huber, Jettenberg, both of Germany Assignee: Firma Buck K.G., Bad Uberkingen,
Germany Filed: Jan. 2, 1974 Appl. No.: 429,738
Foreign Application Priority Data Jan. 5, 1973 Germany 2300472 US. Cl. 102/32; 42/1 Z Int. Cl. F42B 4/26; F423 4/02 Field of Search 102/32, 34.4, 35.6, 37.6,
References Cited UNITED STATES PATENTS Hurst 102/40 392,922 11/1888 Johnson et al 102/40 1,947,834 2/1934 Driggs, Jr. et a1v 102/376 X 2,408,252 9/1946 Ganahl 102/38 X 3,044,360 7/1962 Stefan et al... 102/376 3,782,285 1/1974 Froehner 102/37.6
Primary ExaminerStephen C. Bentley Assistant Examiner-C. T. Jordan Attorney, Agent, or FirmBurns, Doane, Swecker & Mathis 1  ABSTRACT 4 Claims, 2 Drawing Figures US. Patent Oct. 21, 1975 w o w wu Wok 2 v Mom? MANUALLY-OPERATED PROJECTILE-LAUNCHING DEVICES BACKGROUND AND OBJECTS OF THE INVENTION The invention relates to a propellant charge arrangement for manually-operated firing devices wherein the projectile is of relatively high weight in comparison to the weight of the firing device. Such hand-operated firing devices can serve for firing or launching relatively heavy projectiles, such as, for example, incendiary containers or flares, from light launching tubes mostly intended for non-recurrent use. In that case, one disadvantage consists in the fact that because of the unfavorable weight ratio between firing device and projectile, the recoil of the propellant charge can be absorbed by the device only to a very small degree. This in turn either limits the achievable firing range or the weight of the projectile, if the device is to be handled without danger and with accuracy.
It is a general object of the invention to obviate or minimize problems of the sort previously discussed.
It is a particular object of the invention to decrease the recoil of the above-mentioned devices considerably, without decreasing the weight of the projectile and the range of firing.
SUMMARY OF A PREFERRED EMBODIMENT OF THE INVENTION According to the invention, these objects are accomplished by a multi-stage propellant charge arrangement for a hand-operated firing device. This charge is characterized by being subdivided into (1) a comparatively small butquickly burning-down initial charge portion for nudging the quiescent projectile during a first firing stage, and (2) a relatively large thrust charge which burns-down with delay and is arranged at a distance from the initial charge, for accelerating the nudged projectile to the desired muzzle velocity during a second firing stage. Preferably, in this case the initial charge is tamped, the thrust charge untarnped.
The idea of diminishing the recoil of a propellant charge by splitting it up was, to be sure, known previously, but not the special manner of splitting-up proposed by the invention. Precisely this special manner of splitting-up of the propellant charge, however, does make itpossible to decrease the recoil considerably in the case of manually-operated firing .devices of the aforementioned type. The small initial charge burns off quickly and nudges the quiescent projectile and detonates the thrustcharge. whereupon, the more slowly burning-off thrust charge highly accelerates the projectile, which projectile is already in motion as a result of the thrust of the initial charge, to the desired final velocity.
In the case of a projectile of given weight, the hardness or intensity of the recoil depends essentially on the acceleration with which the projectile is to be put in motion. Since the maximum recoil force caused by either stage of the subject charge is less than that which would be caused by the chargeas a whole, the forceof the recoil will be essentially reduced in this manner. The different buming-ofi' periods of the two portions of the propellant charge, likewise has a recoil-diminishing effect, which can be achieved best by the variable tamping mentioned.
Regarding the initial charge portion, the preferably high degree of tamping thereof causes a short, comparatively weak thrust on the bottom of the projectile base. As a result, the projectile is placed in motionvery quickly.
The u'ntamped thrust charge, which burns off subsequently, reacts more slowly on the other hand. As a result, the rough initial thrust is transformed into a smooth thrust.
By the special separation 'of both charge portions, a delay in firing between the initial charge and the thrust charge will be brought about. This delay is, on one hand, to be long enough to assure that the thrust charge is fired only after starting of the projectile. On the other hand, the delay is to be short enough to insure that the thrust charge will burn up completely while the projectile is still in the barrel of the firing device, so that the projectile is accelerated to its maximum velocity. However, none of the previously-known splittings of the propellant charge is capable of meeting these demands. Only the claimed splitting-up of the propellant charge according to the invention is known to be so capable.
THE DRAWING The invention will now be explained in more detail on the basis of the drawing:
FIG. 1 shows a side elevational view schematically and partially in section, of a traditional firing device with the customary propellant charge, and
FIG. 2 shows the same view of the manually-operated firing device of FIG. 1 with the propellant charge according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION According to FIG. 1, a conventional manuallyoperated firing device of the type in question consists essentially of a guide tube 10, a handle 11, which can be snapped-on to the tube, and a trigger 12. In the guide tube 10, a tamped (i.e., compressed) propellant charge 13 and a projectile 14 are housed. By operating the trigger 12, a percussion cap will be fired by a firing pin, which on its part will ignite the propellant 13 in a conventional manner. The propellant l3 burns off quickly because of the tamping and imparts the required muzzle velocity to the projectile l4. Accompanying this, however, is a hard recoil of considerable volume.
According to FIG. 2 the preferred firing device of the present invention includes a guide tube 10, a handle 1 1, and a trigger 12v arranged conventionally. However, the propellant charge is subdivided into a tamped initial or first-stage charge portion 13a housed .within a container 16 attached to the firing device, and an untamped thrust or final-stage charge portion 13b, connected with the bottom of the projectile 14. Upon operation of the trigger 12, the firingpin strikes the percussion cap and firesthe initial charge portion 13a. This detonation force strikes and nudges the projectile l4 and eventuallyfires the thrust charge portion 13b connected with the bottom of the projectile. The thrust .charge portion 13b, upon being detonated, accelerates the projectile 14 to the muzzle velocity.
The initial charge portion 13a is considerably smaller than the thrust charge portion 13b. The weight ratio of the initial charge portion to the thrust charge portion is preferably at least 1:5, and may be 1:7 for example.
The total weight of the tamped initial charge portion and the untamped thrust amounts portion is to be somewhat higher than that of a customary, tamped, ungauged propellant charge; the weight increase preferably amount to about 50 percent. The reason for this is that according to the invention, the largest portion of the charge, (i.e., the thrust portion 13b), is untamped. The special distance between the initial charge portion 13a and the thrust charge portion 13b is dimensioned such that the effective detonation of the thrust charge 13b begins (I) only after the projectile 14 has been struck and nudged by the detonation force of the initial charge portion but (2) in time to assure that the thrust charge portion 13b can burn-off completely while the projectile 14 is still in the tube 10. This delay in firing by spatial separation can be supported by suitable barriers or coverings, such as, for example, thin foils of tin, lead or paper 15 between the initial and the thrust charge portions 13a, 13b.
The untamped thrust charge portion 13b burns more slowly than the initial charge portion 13a. This is important because it enables a suitable muzzle velocity of the projectile to be reached, with minimum recoil effects.
The following numerical examples are to serve merely for an easier understanding of the invention. For the firing of a projectile with a weight of 225 grams, according to the status of the prior art a tamped propellant charge with a weight of 0.9 grams is used. However, firing the same projectile according to the present invention, a highly tamped initial charge portion with a weight of 0.2 grams and an untamped thrust charge portion of 1.3 grams can be used. In this instance, assuming the same range (i.e., distance) of firing, with the recoil measured in kilopound, the maximum recoil is decreased to about one-half by the present invention. Naturally, this considerably facilitates the handling of the device and considerably increases its accuracy.
Naturally, whenever a decrease of the recoil is not required, the invention can serve for increasing the range and/or the weight of the projectile. In other words, for a given recoil force, the present invention allows a larger charge to be used compared with the prior art and thus enables the projectile weight and/or firing distance to be increased.
OPERATION By actuating the trigger 12, a percussion cap will be fired by a firing pin, as is conventional. The first-stage charge portion 13a is thus ignited and quickly explodes. The impulse of this explosion acts upon the projectile 14 to nudge it into movement just prior to the point in time when the products of combustion heat the finalstage charge portion 13b sufficiently to detonate the latter. Detonation of the final-stage charge portion 13b produces additional thrust to further accelerate the projectile and launch it at a suitable muzzle velocity. Importantly, the final-stage charge portion 13b burns more slowly than the first-stage charge portion 13a due to the difference in the degree of tamping, so that the recoil effects from the final-stage charge portion 13b are minimized.
Precise control of the delay between ignition of the firstand final-stage charge portions 13a and 13b may be provided by the selective use of shields 15 between these charge portions.
Finally, we should still like topoint out, that for reasons of safety the initial charge portion 13a should be sufficiently strong to eject the projectile 14 from the tube 10 in case of failure of the thrust charge portion 13b. An emergency ejection range of 5 to 10 meters is advantageous.
SUMMARY OF MAJOR ADVANTAGES AND SCOPE OF THE INVENTION The present invention provides a simplified, yet highly effective, arrangement for firing projectiles with less recoil force. This affords a significant increase in firing accuracy and handling ease.
The present invention may be employed to discharge a given projectile with reduced recoil, or to discharge a longer projectile without unduly increasing the recoil force.
These advantages are afforded without altering the manual discharge procedure of the firing device.
Although the invention has been described in connection with a preferred embodiment thereof, it will be appreciated by those skilled in the art that additions, modifications, substitutions and deletions not specifically described may be made without departing from the spirit and scope of the invention as defined in the appended claims.
What is claimed is:
l. A manually-operated firing device having a handled guide tube, a projectile disposed in said handled tube having a greater weight than said handled tube, propellant charge means disposed in said handled tube, and triggering means for detonating said propellant charge to launch said projectile from said handled tube, said propellant charge means comprising:
an initial-stage propellant charge portion mounted on said guide tube behind said projectile for imparting initial velocity to said projectile within said guide tube; and
a final-stage propellant charge portion disposed behind and connected to the projectile at a distance ahead of said initial-stage charge portion such that ignition of said final-stage charge portion occurs in response to and subsequent to ignition of said initial-stage charge portion;
said final-stage charge portion being of greater weight than said initial-stage charge portion and being arranged to burn more slowly than said initial-stage charge portion at a rate sufficient to burn out prior to discharge of said projectile from said tube to accelerate the projectile from said initial velocity imparted by said first-stage charge portion to said discharge velocity.
2. A firing device according to claim 1 wherein said initial-stage charge portion is tamped and said finalstage charge portion is untamped.
3. A firing device according to claim 1 wherein said device includes barrier means disposed between the initial-stage and final-stage charge portions; said barrier means being comprised of a material suitable for being melted by ignition of said initial-stage charge portion and delaying ignition of said final-stage charge portion until said projectile begins initial movement.
4. A firing device according to claim 1 wherein the weight of said final-stage charge portion is at least five times the weight of said initial stage charge portion.