DEVICE FOR A GRENADE PRESSURE PLATE AND SEALING MEANS FOR A PRESSURE PLATE OF A GRENADE

Abstract: For a shell thrower the grenade is inserted in a barrel and a booster charge under the grenade will fire and generate a gas pressure which forces the grenade out of the barrel. In order to improve the driving charge acting on the grenade it is hereby proposed that a pressure plate (1) is detachably fixed under the grenade (2), and that the booster charge (3) is located on the underneath side of the pressure plate (1). An ignition mechanism for the booster charge (3) is arranged on the underneath side of the pressure plate, which ignition mechanism (4) is initiated by the impact of the pressure plate (1) against the bottom or a shoulder of the barrel. A releasable engagement (5) is arranged between the upper side of the pressure plate and the bottom of the grenade, which engagement includes a locking means, which is released from its locking position by means of a part of the driving pressure of the booster charge.

Description: Device for a grenade pressure plate and sealing means for a pressure plate of a grenade. The present invention relates to a means for a grenade of a shell thrower, where the grenade is inserted in the barrel and a booster charge under the grenade is fired to generate a gas pressure, which drives the grenade out of the barrel. An object of the present invention is to improve the power of the booster charge on the grenade so that there is a possibility to arrange a sealing between the grenade or a part of the grenade and the bore of the barrel. It is hereby possible to use most part of the gas pressure of the fired booster charge for ejecting the grenade. In order to achieve this object the invention has the charac¬ terizing features which are stated in the following claims. The invention will be described in the following by reference to the enclosed drawings. Fig. 1 shows a longitudinal section of the lower part of the grenade and its pressure plate. Fig. 2 is a longitudinal section of the pressure plate and a part of the surrounding barrel and shows the function of the pressure plate as a valve when the grenade is fired. The left side of fig. 1 shows the form of the valve when the pressure plate is inserted in the barrel. Fig. 3 is a plan view of the valve element in the firing position but in a smaller scale than in fig. 2. Fig. 4 is a view of the form of the valve element in its rest position and in a smaller scale than in fig. 2. Fig. 1 shows the lower part 2 of a grenade schematically. A pressure plate 1 is detachably fixed on the bottom of the grenade and the pressure plate includes a booster charge 3. The booster charge is placed on the underside of the pressure plate. An ignition mechanism 4 for the booster charge is arranged on the underside of the pressure plate and could be a common lasting cap, which is initiated by an impact. The ignition mechanism or the blasting cap 4 is initiated by that the pressure plate is inserted together with the grenade 2 in the barrel and hits the bottom of the barrel or a stop pin in the barrel. A releasable engagement 5 connects the pressure plate 1 with the underside 6 of the grenade 2. This releasable engagement 5 consists of a sleeve 7 which is fixed to the upper side of the pressure plate. A pin 8 is inserted from above in the sleeve, which pin for instance is threaded into the bottom 6 of the grenade 2. A locking pin 9 is inserted in a bore 10, which is extended through the sleeve 7 and into the pin 8. The bottom 11 of the bore 10 is connected with a channel 12, which is extended through the pressure plate and to the bottom of the sleeve 7. The operation of the pressure plate is as follows. When the booster charge is initiated by the ignition mechanism 4 and thus is fired, a gas pressure is generated, the main object of which is to eject the pressure plate together with the grenade out of the barrel. A part of the driving pressure of the booster charge will however be conducted by the channel 12 to the bottom 11 of the bore 10 in the pin 8. The locking pin 9 will hereby be driven out of the bore 10 and the pressure plate is released from the grenade. Because the pressure plate is smaller and lighter than the grenade, the pressure plate, after having left the barrel together with the grenade, will fall down to the ground just outside the barrel whereas the grenade 2 will proceed from the shell thrower in a certain path. Fig. 2-4 shows the pressure plate operating as a sealing valve 13. The pressure plate (the sealing valve) includes a valve element 29, which is located in a groove 25 in the envelope surface of the pressure plate 1. The groove 25 is beveled from its upper edge 27 so that the upper inner side of the edge forms an angle α with the diametrical plane 26. The valve element 29 mounted in the groove 25 has a beveled upper side 30 corresponding to the slopeness of the side 27 of the groove. The valve element 29 is spring expanding which means that when there is a pressure from underneath, see arrow 14, it will be forced upwards and outwards out of the groove and hereby against the inside of the barrel 23, which causes a seal so that the gas pressure can not pass between the pressure plate 1 and the inside of the barrel 23. The valve element is thus spring expanding, which means that when there is no pressure from underneath it will get the form shown in the left side of fig. 2. This also means that when the shell thrower is loaded and a grenade with its pressure plate is inserted from above into the barrel, the air, which will be compressed under the pressure plate, will pass between the pressure plate and the inside of the barrel. The spring property or the elastic property of the valve element is now adjusted so that when a high gas pressure is generated by firing the grenade, and the gas pressure is directed towards the side 21 of the valve element which is faced downwards, the valve element will slide against the beveled side 27 and be displaced against the inner side of the barrel. A high pressure is needed for this and fig. 3 shows that the valve element is divided radially so that it can expand. Preferably the pressure plate is so formed that the lower end part, which is under the groove 25 and is faced to the gas pressure, has a less diameter in order to ensure that enough pressure will reach the free side 21 of the valve element. The main part of the gas pressure will strike the underneath side 24 of the pressure plate but enough gas pressure must thus pass around the pressure plate and reach the valve element 29. The size of the angle α has an influence on the pressure which forces the valve element against the inner side 22 of the barrel when firing the booster charge. The valve element can be produced from many different materials as plastic, rubber, steel or other metals depending on type of booster charge and the force from the booster charge.

Claims: CLAIMS 1. Sealing means for a grenade of a shell thrower, where the grenade is inserted in a barrel and a booster charge under the grenade will fire and generate a gas pressure which forces the grenade out of the barrel, c h a r a c t e r i z e d i n that a pressure plate (1) is detachably fixed under the grenade (2), that the booster charge (3) is located on the underneath side of the pressure plate (1) , that an ignition mechanism for the booster charge (3) is arranged on the underneath side of the pressure plate, which ignition mechanism (4) is initiated by the impact of the pressure plate (1) against the bottom or a shoulder of the barrel, whereat there is a releasable engagement (5) between the upper side of the pressure plate and the bottom of the grenade, which engagement includes a locking means, which is released from its locking position by means of a part of the driving pressure of the booster charge. 2. Means according to claim 1, c h a r a c t e r i z e d i n that the pressure plate is formed with a channel (12) going from its under side (2) to a sleeve (7) on the upper side, that there is a pin (8) on the bottom of the grenade, which pin is insertable in the sleeve (7), that a locking pin (9) is insertable from the side of the sleeve into the pin through a bore (10) through the sleeve (7) and into the pin (8), whereat the bottom of the bore (10) is connected with the channel (12) going through the pressure plate (1) . 3. Means according to claim 1, c h a r a c t e r i z e d i n that the pressure plate (1) has a surrounding groove (25) in its envelope surface, which groove is located in a diametrical plane (26), and which groove (25) has two groove sides (27, 28), which the one facing the pressure side (27) is incleaning from the pressure end (24) of the pressure plate in the direction from the inner end of the groove and outwards and thus forms a certain angle a with the diametrical plane (26) , and that ring-shaped valve element (29) is located in the groove, which valve element is spring expanding in radial direction and has a surface (30) which is parallel to said incleaned groove side (27) and slides on said groove side (27), and which valve element (29) has a second face (21), which at least partly is facing the pressure end (24) of the pressure plate and is free from the groove (25) so that the gas pressure can act against said face (21), whereby the valve element (29) when sliding on the incleaned groove side (27) will expand to contact the inner side (22) of the barrel (23) by the action of the gas pressure and will retain its original form when the gas pressure is released. 4. Means according to claim 3, c h a r a c t e r i z e d i n that the angle α with the diametrical plane (26) is in the order of 45°. 5. Means according to claim 3, c h a r a c t e r i z e d i n that the cross section of the valve element (29) is triangular. 6. Means according to claim 3, c h a r a c t e r i z e d i n that the diameter of the pressure plate (29) is less on the pressure side (24) underneath the groove (25) than the diameter of the upper part of the pressure plate. 7. Means according to claim 3, c h a r a c t e r i z e d i n that the valve element (29) is divided radially in order to be able to extend.

Inventors: ROHEIM KARL-AXEL, ROHEIM, KARL-AXEL
Applicants: ROHEIM KARL AXEL, ROHEIM SYSTEM, ROHEIM, KARL-AXEL
Application year: 1996
Main classification: F42B30
IPC codes: F42B14, F42B30