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The new military rifle
13 2
CURRENT TOPICS.
[]. F. I.
devices for e m p l o y i n g his improved coherer as a relay upon a relay in a telegraphic outfit for receiving wireless messages. This last application caused world-wide interest in the coherer, and numerous experimenters began work upon it. Decoherence was produced in the metallic filings coherer by tapping, slowly revolving the tube. T. Tomasina was the first to use magnetic means directly for producing decoherence. He placed an electromagnet over the tube and in series with the coherer so that when it became sensitive the magnet was energized and lifted the granules to the top of the tube, thus producing decoherence. This method has been applied to a coherer developed by the General Electric Company, to be used in connection with discharge alarms for lightning arresters, high-frequency alarms, etc. T h e N e w Military Rifle. A. ]3. BOWERS. (Scientilic American, vol. cxvi, No. 19, p. 474, May 12, I g I 7 . ) - - T h e regular army rifle, while in most respects an admirable weapon, is, in the opinion of many competent observers, open to grave objections on more than one ground. In the first place, the trigger by which the rifle is discharged is located below the stock, between narrow, opensided guards, which are far from sufficient protection. Moreover, the manner of discharge, by pressure of the forefinger on the trigger, produces in many cases a sidewise and downward movement of the whole barrel sufficient materially to affect accuracy of aim. A far greater measure of inaccuracy in shooting is caused by the short distance between the sights. The back-sight is too far forward--. from 12 to 18 inches from the eye. This defect cannot, however, be remedied off-hand, for, with the open back-sight used, this distance is necessary for accurate focussing of the two sights upon the target. Again, many users of rifles carry them at full cock so that they may be ready for instant use by releasing a locking device. Finally, in cold weather the gloved finger is too stiff to manipulate with safety the trigger now in use. A Brooklyn inventor claims to have eliminated these various defects in a new gun recently patented. H e has substituted for the old projecting finger-trigger under the stock a thumbtrigger above the stock. In operation it is only necessary to tighten the grip of the hand slightly in order to work this trigger; and at rest it is possible to guard it by a five-sided guard. A long-sighting range has been obtained, without any of the disadvantages enumerated, by attaching a peep-sight to the firing pin. In this way a broad base is obtained sliding in closely-fitting guards that preserve the alignment. Not only does this give the desired long- sighting range, but, bringing the back- sight to within four inches of the e.ye, it permits the use of a peep-sight small enough to insure accurate aim. The conflict between cocking and locking is automatically eliminated, for the base of the peep-sight so completely covers the thumb- trigger, when the gun is at cock, that the necessity
July, 19~7.]
CURRENT TOPICS.
133
for locking is wholly removed. Finally, the motion by which the discharge is accomplished is such a simple one that it can be made without the slightest difficulty, regardless whether the hand be bare or gloved. Industrial Lifting Magnets. J. VICHNIAK. (Le Genie Civil. vol. lxx, No. I6, p. 253 , April 21, I g I 7 . ) - - T h e application of electromagnets to replace the familiar crane hook in handling iron and steel materials has proved of great value in materially reducing the labor entailed in moving about such material in the course of manufacture. Although the principle of the lifting magnet is very simple. it ~vas only after much experimenting that a practical design was evolved adapted to the rugged requirements of rapid handling. The calculation of lifting power for materials with plane surfaces is not complicated, as the total flux and strength can be easily computed. When, however, objects of irregular shape are dealt with, it is only by tentative methods that the best proportions of the magnet can be found for a given class of material. The lifting magnet is particularly useful for material not easily shackled, such as chips from machine tools, various structural discarded odds and ends, and also to material of regular shape of moderate weight. One unique application is in handling hot billets. These pieces, difficult to attach to the ordinary crane hook when hot, are readily raised and removed by the magnet. Special water-cooled magnets are empoyed for this service. It is well understood that the capacity depends upon the proximity of the piece to be lifted to the pole face. To increase the capacity when lifting irregular pieces, the Couffinal works at Saint-Etienne have designed a magnet with subdivided vertically movable pole faces. These subdivided faces, bv their vertical movement, conform to the irregularities of the pieces lifted and prevent lateral motion, as well as increase the lifting capacity. Another special form of magnet for lifting a bundle of rods or other long pieces is provided with a linkage, somewhat after the manner of a clam-shell dredge bucket, operating arms that embrace the load held by the magnet. Once in place, the magnet is de~nergized and the load is transferred to the arms, thus economizing current. T e s t i n g A u t o m o b i l e Engines Electrically. ANON. (Electrical World, vol. 69, No. 12, p. 557, March 24, I 9 1 7 . ) - - T h e use of the g e n e r a t o r for engine testing is in itself an old device, yet there is much of novelty in the technical applications of this famliar process in the testing-room of the T o l e d o plant of the WillysOverland Company. T h e first steps in the testing process are to m o u n t the engine on the testing block and drive the engine at 500 r. p. m., using the g e n e r a t o r as a motor. This overloads the m o t o r by some 300 per cent. for a v e r y brief period, perhaps one to three minutes, at the end of which time the friction load drops
CURRENT TOPICS.
[]. F. I.
devices for e m p l o y i n g his improved coherer as a relay upon a relay in a telegraphic outfit for receiving wireless messages. This last application caused world-wide interest in the coherer, and numerous experimenters began work upon it. Decoherence was produced in the metallic filings coherer by tapping, slowly revolving the tube. T. Tomasina was the first to use magnetic means directly for producing decoherence. He placed an electromagnet over the tube and in series with the coherer so that when it became sensitive the magnet was energized and lifted the granules to the top of the tube, thus producing decoherence. This method has been applied to a coherer developed by the General Electric Company, to be used in connection with discharge alarms for lightning arresters, high-frequency alarms, etc. T h e N e w Military Rifle. A. ]3. BOWERS. (Scientilic American, vol. cxvi, No. 19, p. 474, May 12, I g I 7 . ) - - T h e regular army rifle, while in most respects an admirable weapon, is, in the opinion of many competent observers, open to grave objections on more than one ground. In the first place, the trigger by which the rifle is discharged is located below the stock, between narrow, opensided guards, which are far from sufficient protection. Moreover, the manner of discharge, by pressure of the forefinger on the trigger, produces in many cases a sidewise and downward movement of the whole barrel sufficient materially to affect accuracy of aim. A far greater measure of inaccuracy in shooting is caused by the short distance between the sights. The back-sight is too far forward--. from 12 to 18 inches from the eye. This defect cannot, however, be remedied off-hand, for, with the open back-sight used, this distance is necessary for accurate focussing of the two sights upon the target. Again, many users of rifles carry them at full cock so that they may be ready for instant use by releasing a locking device. Finally, in cold weather the gloved finger is too stiff to manipulate with safety the trigger now in use. A Brooklyn inventor claims to have eliminated these various defects in a new gun recently patented. H e has substituted for the old projecting finger-trigger under the stock a thumbtrigger above the stock. In operation it is only necessary to tighten the grip of the hand slightly in order to work this trigger; and at rest it is possible to guard it by a five-sided guard. A long-sighting range has been obtained, without any of the disadvantages enumerated, by attaching a peep-sight to the firing pin. In this way a broad base is obtained sliding in closely-fitting guards that preserve the alignment. Not only does this give the desired long- sighting range, but, bringing the back- sight to within four inches of the e.ye, it permits the use of a peep-sight small enough to insure accurate aim. The conflict between cocking and locking is automatically eliminated, for the base of the peep-sight so completely covers the thumb- trigger, when the gun is at cock, that the necessity
July, 19~7.]
CURRENT TOPICS.
133
for locking is wholly removed. Finally, the motion by which the discharge is accomplished is such a simple one that it can be made without the slightest difficulty, regardless whether the hand be bare or gloved. Industrial Lifting Magnets. J. VICHNIAK. (Le Genie Civil. vol. lxx, No. I6, p. 253 , April 21, I g I 7 . ) - - T h e application of electromagnets to replace the familiar crane hook in handling iron and steel materials has proved of great value in materially reducing the labor entailed in moving about such material in the course of manufacture. Although the principle of the lifting magnet is very simple. it ~vas only after much experimenting that a practical design was evolved adapted to the rugged requirements of rapid handling. The calculation of lifting power for materials with plane surfaces is not complicated, as the total flux and strength can be easily computed. When, however, objects of irregular shape are dealt with, it is only by tentative methods that the best proportions of the magnet can be found for a given class of material. The lifting magnet is particularly useful for material not easily shackled, such as chips from machine tools, various structural discarded odds and ends, and also to material of regular shape of moderate weight. One unique application is in handling hot billets. These pieces, difficult to attach to the ordinary crane hook when hot, are readily raised and removed by the magnet. Special water-cooled magnets are empoyed for this service. It is well understood that the capacity depends upon the proximity of the piece to be lifted to the pole face. To increase the capacity when lifting irregular pieces, the Couffinal works at Saint-Etienne have designed a magnet with subdivided vertically movable pole faces. These subdivided faces, bv their vertical movement, conform to the irregularities of the pieces lifted and prevent lateral motion, as well as increase the lifting capacity. Another special form of magnet for lifting a bundle of rods or other long pieces is provided with a linkage, somewhat after the manner of a clam-shell dredge bucket, operating arms that embrace the load held by the magnet. Once in place, the magnet is de~nergized and the load is transferred to the arms, thus economizing current. T e s t i n g A u t o m o b i l e Engines Electrically. ANON. (Electrical World, vol. 69, No. 12, p. 557, March 24, I 9 1 7 . ) - - T h e use of the g e n e r a t o r for engine testing is in itself an old device, yet there is much of novelty in the technical applications of this famliar process in the testing-room of the T o l e d o plant of the WillysOverland Company. T h e first steps in the testing process are to m o u n t the engine on the testing block and drive the engine at 500 r. p. m., using the g e n e r a t o r as a motor. This overloads the m o t o r by some 300 per cent. for a v e r y brief period, perhaps one to three minutes, at the end of which time the friction load drops