US2938513A - Air gun - Google Patents

Description

AIR GUN May 31, 1960 4 Sheets-Sheet 1 Filed April 17, 1956 INVENTOP: Kur+ C? v55 3 WM 4mm K. GISS AIR GUN May 31, 1960 4 Sheets-Sheet 2 Filed April 17, 1956 K. GISS AIR GUN May 31, 1960 4 Sheets-Sheet 3 Filed April 1'7, 1956 May 31, 1960 K. GISS 2,938,513

AIR GUN Filed April 17, less 4 Sheets-Sheet 4 INVENT'OIP (KY G 5 United States Patent werk-Mayer & Grammelspacher, Rastatt, Baden, Germany Filed Apr. 17, 1956, N0. 578,794

16 Claims. (CL-124-15) The present invention relates to air guns.

One of the objects of the present invention is to provide an air gun capable'of eliminating recoil and-at the same time having an exceedingly simple operating structure.

Another object of the present invention is to provide an air gun capable of eliminating recoil through the medium of a panel oppositely movable pistons with a means cooperating with only one of the pistons for controlling the operation of the gun.

A further object of the present invention is to provide an air gun of the above type with a structure which guarantees that the pistons will always move equally and oppositely with respect to each other.

An additional object of the present invention is to provide an air gun capable of preventing recoil and having but one .piston which' actually compresses air.

A further object of 'the'present invention is to provide an air gun with a pair of balanced pistons for preventing recoil which also includes a means for automatically regulating the compression chambers which cooperate with these pistons.

Also, the objects of the present invention include the provision of structure capable of accomplishing the above objects and at the same time composed of simple and ruggedly constructed elements which are very reliable in operation.

With the above objects 'in view the present invention mainly consists of an air gun which includes a cylinder in which a pair of pistons are s lidable, at least one of these pistons forming with part of the cylinder a compression chamber. A barrel communicates adjacent breech end with the compression chamber and -a means is operatively connected to the pistons for compelling the same to move at the same speed as well as equally and oppositely with respect to each other.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 is a fragmentary longitudinal sectional view of one possible construction of an air gun according to the present invention;

Fig. 2 is a fragmentary sectional view taken along line 2-2 of Fig, 1 in the directionof the arrows;

Fig. 3 is a longitudinal'sectional fragmentary view of an air gun similar to Fig. 1 having a shiftable partition in the cylinder between the pistons therein;

.Fig. 4 is a sectional elevational view taken along line 44 of Fig. 3 in the direction of the/arrows;

Fig. '5 is an elevational longitudinal sectional 'view through another embodiment of an air gun according to the present invention; and

Fig. 6 is a fragmentary longitudinal-sectional eleva- 2,933,513. Patented May 31, 1960 2 tional view of an air gun similar-"to Fig. 1 buthaving only one piston which actually compresses air for discharging a projectile from'the barrel.

In the embodiment of the invention which is shown in Figs. 1-4 pistons 1 and 2 are slidable within a cylinder 3. In the arrangement of Fig. 1 a compression chamber Sais formed in the cylinder 3 between the pistons 1 and 2 while in Fig. 3 there is shown a partition 30 between the pistons 1 and 2 which provide a pair of compression chambers 3a cooperating with the pistons 1 and 2 of Fig. 3. The piston sealing members 5 associated with the pistons 1 and 2 of the Fig. 3 are diiferent from the sealing'inember's 5a of the pistons 1 and 2 of-Fig. 1 and cooperate properly with the partition 30. In Figs. 1 and 3 there is shown the barrel 4 which is-fixed to the cylinder 3 and which communicates with the compression chamber 3:: through a bore 3b which is of extremely small size. As is particularly evident from Fig. 4, the bore 312 communicates with an annular channel formed in the barrel 4 adjacent its breech end where the sealing ring 4a is located, and this annular channel in turn cooperates with bores passing from the annular channel through the wall of the barrel to the interior thereof, as is shown at the upper portion of Fig. 4. The partition 3csho'wn in Fig. 3 is freely shiftable within the cylinder 3 and is formed with passages which communicate with the portions of chamber 311 on opposite sides of the partition 30 as well as with the bore 3b, as shown in Fig. 3.

The cylinder 3 of Fig. 3 is provided at its lowermost inner surface portion beneath the bore 3b with a projection 3d which is located within an annular groove 31 formed in the outer periphery of the partition3c, and this partition 3c is itself provided within the groove 31 with a pair of projections 3e, as shown in Fig. 4. In the groove 3f of the partition 30 there are pressed a pair of brake lining members 3g in the manner shown in Fig. 4, so that the projection 3d of the cylinder 3 is located between the brake lining members 3g and 'so that the upper ends of the latter respectively engage the projections 3e. With this arrangement there is a frictional engagement between the members 3g and the inner face of the cylinder 3 which maintains the partition 3c in the position -to which it is automatically moved by the pistons 1 and 2. Furthermore, the cooperation of the projection 3d with the members 3g prevents turning of the partition 3c about its axis and limits it to axial move ment. The extent of axial movement of partition 3c is small, but as is clearly evident from Fig. 3, there is a sufficient degree of axial movement of the partition 3c to enable the latter to be properly positioned by the pistons 1 and 2 themselves Without the possibility of cutting oif communication between the passages in the partition 31: with the bore 3b.

The cylinder 3 is formed with a .pair of axial slots which are overlapped by the pistons 1 and 2 in the position thereof shown in Figs. '1 and 3 and which do not extend beyond the head ends of the pistons 5 or 5a. A pair of racks 1a and 2a are fixed to extensions which extend through these slots and are respectively fixed to the pistons 1 and 2 adjacent their rear ends, respectively, so that in this way the racks 1a and 2a are movable togather with the pistons and are capable of moving the latter, while at the same time the compression chambers 32: do not communicate with the outer atmosphere because the slots do not extend up to the compression chamber when the pistons are in their starting position shown-in Figs. 1 and 3. As is evident from Fig. 2, the racks 1a and 2a are laterally spaced from each other and respectively mesh with opposite sides of a pinion 6 which is turnably carried by a pin 6a which'is in turn carried by a substantially U-shaped bracket 6b which has its upwardly extending legs fixed to the cylinder 3 at the q .5 outer surface thereof approximately midway between to make certain the latter is located in proper firing posithe pistons when the latter are in the position shown in I Figs. 1 and 3. The teeth of the racks 1a and 2a are directeditoward each other and these racks respectively have smooth faces directed away from each other and. engaging the rollers 60 which are also turnably' carried by the bracket 6b and which guarantee that the racks 1a and 2a remain in meshing engagement with the pinion 6. Thus, the racks and pinion form a means for. compelling the pistons to move at all times at the same speeds and in equal and opposite directions.

A cocking lever 8 is pivoted at 8a to a forwardly extion, as shown in Fig. 3. Furthermore, it will be noted that the frusto-conical portion of the pin 12 immediately behind the front end portion 12a thereof cooperates with the sealing ring 4a to close the rear end of the barrel 4. Now, when the triggerlljs actuated by the operator who turns the trigger 11 into counterclockwise direction,

the rack 2a will be released, andthe springs 7 will move tending projection of the cylinder 3, and a link 10 is .7 I

pivoted at ltlizto the cocking lever 8. This link 10 is in turnpivotally connected at 9a to a motion transmitting member 9 which extends through the space between. the pinion 6 and the cylinder 3 to the rear end of the latter where the motion transmitting member 9 has an upwardly extending leg fixed to the rear'end of an elonthat the projectile 13 is located ahead of the barrel opening which communicates .with ,the compression chamber of the cylinder 3. Thus, it will be seen that the pin 12 guarantees that the motion transmitting member 9 is guided for horizontal forward and rearward movement, and this motion transmitting member 9 has a shoulder 9b which engages the front end 2b of the rack 2a .whenthe cocking lever 8 is turned from the position of Fig. 3 to that of Fig. 1, so that in this way the motion transmitting member 9 moves the rack 2a to the rear whenever the cocking lever 8 is actuated. The motion transmitting member 9 engages only the rack 2a, the rack 1a moves because of its connection to the rack 2a through the pinion 6. Springs 7 are located in the cylinder-3 and urge'the pistons 1 and 2 toward eachother, respectively, so. that when the cocking lever 8 is actuated the springs 7 are compressed and volume of the compression chamber 3a increases.

' The rack 2a is provided at its rear end portion witha pawl 2c which cooperates with a tooth of a trigger 11 which is pivotally carried by a projecting portion which extends iearwardly and downwardly from the rear end of the cylinder3. The spring shown atthe lower right portion of Figs..1 and ,3 urges the trigger 11 to the pistons 1 and 2 toward each other so that the air compressed within the; compression chamber 3a drives the projectile '13 out of'the barrel. The gun is provided with a suitable stock which is not illustrated since it forms no part of thepresent invention.- g

In the embodiment of the invention which is illustrated in Fig. 5, the barrel4 is alsdfixe'd to the cylinder 3 within which the pistons 1 and 2are slidably located for movement toward and away from each other. As is evident from Fig. S the pistons are formed with elongated slots cooperating with slots formed in the portions of cylinder 3 which are located' beyond the head ends of the pistons 1 and 2 in the position thereof shown in Fig. 5, so that a pair of. levers 5 and 5a may extend through the pairs of aligned slots into the interiors of I the pistons 1 and 2 behind the head ends thereof. Rollers carried by the free ends of the levers 5 and 5a engage the pistons 1 and 2. Furthermore, the rear edge portions of the levers 5 and 5a adjacent their upper ends engage the rear ends of the slots formedin the pistons 1 and 2 so that the levers are capable of moving the pistons. Acompression chamber 311 is formed in the cylinder 3 between the pistons 1 and 2.

The levers 5 and 5a are housed within the hollow handle 6 of the gun of Fig. 5, and they are pivotally turn in a clockwise direction, as viewed in Figs. 1 and 3,"

so that when the tooth 2c rides over the tooth of the trigger 11 the latter will catch the rack 2a and will retain the latter in the position shown in Figs. 1 and 3.

A safety bell crank member 11a is pivotally carried by the rear projection of the cylinder 3 for turning movement about the same pivot pin which turnably carries the trigger 11, the latter being limited in its forward movement by the recessed portion of the projection of cylinder 3 which carries the spring which acts on the trigger 11. The bell crank safety member 11a alsohas a tooth which cooperates with the tooth 20 to retain the rack 2a in the position shown in Fig. 1 until the cocking lever 8 is returned to its rest position shown in Fig. 3. The motion transmitting member 9 has a tooth carried by the pivot pins 5b, as shown inFig. 5. Furthermore. the.'levers 5 and 5a are formed with gear sectors 5c, respectively, whose centers of curvature coincide with the axes of pivot pin 5b. These gear sectors 5c which mesh with each other thus compel the levers 5 and 5a to turn at all times equally and oppositely with respect to each other. A compression spring 7 is located betweenand engages the bottom free ends of the levers 5, and 5a to urge the latter apart from each other, the gun being shown in Fig. 5 in its cocked position where the spring 7 has been compressed.

I The cocking lever 8 of the embodiment of Fig. 5 is in the form'of an elongated channel of substantially U- shaped cross section which forms an'outer covering of the barrel 4 when thegun is in the position shown in Fig. 5. As isevidentfrom Fig. 5 the front end of the cocking lever 8.has an opening aligned with the muzzle end of the barrel 4, and furthermore the cocking lever 8 is provided with openings through which the sighting and aiming projections 14 and 15 respectivelyextend, projection 14 being fixed to the barrel 4 while the projection 15 is fixed 8. 7 Thus; when the cocking lever 8 is turned from the 90 which engages the top end, of the lever 11a when the cocking lever 8 is returned from the position of Fig. 1 to that of Fig. 3, and thus when this'cocking lever is located in the position of Fig. 3 the tooth 90 turns the safety lever 11a to the position shown in Fig. 3, so-that now the rack 2a is held in its cocked position only by the trigger 11.

It is evident that when the gun is thus cocked, the breech end of the barrel 4 is opened, and a projectile 13 may be placed through'the sealing member 4a in the interior of the barrel 4. Then when the lever 8 is returned to its rest position shown in Fig. 3, the pin 12 engages with its front end portion 12a the projectile 13 position shown in Fig. 5 in solid lines to the position shown fragmentarily in dot-dash lines, the motion trans: mittin'g hook member 9 engages the lever 5a at the angle portion 511 thereof, as shown in Fig. 5, and thus the lever 5a is turned in a clockwise direction to the position shown in'Fig. 5, this turning of the lever 5a compelling the lever 5 to turn in a counterclockwise direction to the position shown in Fig. .5, and the spring 7'thus being compressed.

. It will be noted that the lever 8 carries, a plug So which extends into and fills the gap between the breech end of the barrel 4 and the projection -15.. This plug 8c forms an air-tight seal with the breech end of the barrel when the cocking lever .isin its rest position shown in Fig. 5, and the-plug 8c is formed with a passage 8d providing communication between the compression chamber 3aand the breech'end 4a of the barrel 4.

When the lever 8 is in the-dot-dash line position'shown inFig. .5, *a spring which acts on the pawl member 12 causes the tooth of the latter to engage the tooth sf of the lever 5, so that the pawl member .12, which ispivoted within the housing '6, forms asafetycatch which retains the parts in the position shown in Fig. 5 temporarily. Furthermore, the lever 5- has a tooth 5e which'cooperates with the corner 11a of the trigger -1-1 which is accessible through an opening formed in the housing-6 to the finger of the operator. Thus, cooperation between the trigger 11 and the tooth 5e also retains 'theipartsin the position shown in Fig. 5, and it will be noted that aspringis located between and engages the'trigger 1:1 and the levers to urge the latter apart from each other, this sprin'glguab anteeing that the trigger 11 remains in the position shown in Fig. 5 where it is available to the'operator for actuation of the gun.

The lever 8 has a downwardly extending projection which extends through a suitable cutout within the housing 6 into engagement with the upperface portion of'the lever 12 so as to turn the latter in a counterclockwise rection to the position shown in Fig. 5 when the lever 8 is returned to its rest position shown in solid lines'in Fig. 5, and in this way the tooth 1-2ais moved out of engagement with the tooth 51, so that when the lever 8 is returned to its rest position the safety catch is disengaged and the gun is ready to fire. Of course, before the lever 8 is returned a projectile is placed into the barrel through the opening 4a thereof. Also, the gun includes a-manually operable locking pin 13 which extends over the bottom projection of lever '8 which engages the safety member 12 in order to maintain the lever 8 in the position :shown in Fig. 5. This locking member 13:extends through an opening in the front wall of the housing 6 and has a pair of shoulders which 'may be optionally placed in en- :ga'gement with the inner face of the housing by the operator. As shown in Fig. 5, a spring urges the locking member 13 outwardly, and it is guided on a projecting por- "tion located within the housing 6 for forward and'rearward movement as well as for lateral movement. The spring engages one of these projections in the housing 6 and also engages the pin 13 in the manner shown in Fig. 5. Thus, when it is desired to release the lever 8 for operation the operator need only push the pin 13 in slightly and then push it laterally away from engagement with the lever 8 which is then free to be moved to the dot-dash line position shown in Fig. 5. Then the'pin 13 may be returned to the position shown in Fig. 5 after l'ever 8 is returned to its rest position in order :t'ore'tain the lever 8 in its rest position.

With the gun thus cocked and with a projectile located in the barrel 4, it is only necessary for the operator to pull the trigger 11 in order to release the lever 5, and in this way the force of the spring 7 acts'through the levers "5 and 5a on the pistons 1 and 2 to move the latter toward each other, so that in this way air within the compression chamber 3a moves through the passage 8d into the barrel in order to expel the projectile through the barrel.

It will be noted that the pistons land 2 of Fig. 5 are provided with portions 2a at the ends of the slots therein which engage the edges of the levers 5 and 5a. Furthermore, it will be noted that the trigger 11 is located behind a portion of the lever 5, in Fig. '5, and that the projection "5c of the lever 5 extends from the lever 5 into engagement with the trigger 11.

In the embodiment of the invention which is shown in Fig. '6, the structure is identical with that of Fig. 3 except that instead of a shiftable partition 3c'the embodiment of Fig. 6 includes a partition which is fixed within the cylinder 3 and which is formed with a bore, as shown in Fig. '6

'barrels as well as tiltable barrels. a

ZEhe piston .2 'acts only as .a balance in order to prevent recoil. For this v purpose the .piston '2 istormed with a thickenedhead end so that it has the same weight as the piston 1, and it will be noted that the head end of the piston 2 inthe embodiment of F-ig, 6 ,is formed with a relatively large opening-so that no air compressed by t-hepiston-2. 1 I 1 .It will be noted that with the above described structure oi -the invention although a pair of pistons move in opposite directions with respect to each other and atthe same speeds the structure for controlling the release of the pistons and the eockingof the air gun operates on only one of the pistons rather than on both of them. The piston which is not acted upon by the cocking and releasing structure is maintained in its proper position by its connection to the piston which is acted upon by the cocking and releasing structure.

Although particular structures have been described above, it is possible instead of using a pair of pistons to use a pair of groups ofpistons, and instead of operating with gear sectors or with racks andpinions, it is possible to use scissors-type linkages, bell crank linkages, cables and pulleys, or sprocket wheels and sprocket chains, or lthe like. Also, instead of using pistons which cooperate with compression chambers located outside of the pistons, it is possible to use with the structure of the invention pistons which have the compression chamber in themselves, and this latter type of arrangement has the advantage of an exceedingly small passage between the barrel and compressioncha'rnber. This -is true for fixed It will be understood that 'each of the elements described above, or two or more together, mayalso find a useful application in other types of air :guns difiering 'from the types described above.

While the invention :has been illustrated and described as embodied in recoiltess fair guns, it is not intended to be limited to the details shown, since various modifications and structural changes maybe made 'without departtended to be comprehended within the meaning and range of equivalence 'of the following claims.

What is claimed as new and desired to be secured by letters Patent is:

1. In an air gun, in combination, a cylinder; a of pistons slidable in a direction inwardly toward and in a direction outwardly away with respect to each other in said cylinder and at least one of said pistons forming with part of said cylinder a compression chamber; a barrel connected to said cylinder and communicating adjacent its breech end with "said compression chamber, 'sothat when said one pistonreduce's 'the volume of said compression chamber the air compressed therein will drive aprojectile out of said barrelysepara'teactuating-means for each piston jointly effective to permanently urge said pistons in one of said directions; and synchronizing mea'nscooperative with said actuating means and operatively interconnecting "said pistons in such 'a m'anne'r'that thereby b'oth pistons will move in synchrohi's'm 'at'th'esam'e speed "in their movement in Said 0116 6f said directions at :least during the compression 'stroke; cocking means cooperating 'with said synchronizing means for moving said pistons ito "the end of their respective movementsin the other of said directions against the urging "o'f'said actuating means and for holding them in said positions; and trigger means operable to release said pistons "for movement synchronous'ly insaid one of said directions by "the action o'tsaiit actuating means and said synchronizing means whereby said pistons are adapted to obtain simultaneously the end positions of their movements in said one of said "directions;

2. In an air gun, in combination, a cylinder; a pair of pistons slidable inwardly toward and outwardly away with respect to each other in said cylinder and at-least one of said pistons forming with part of said cylinder a compression chamber; a barrel'connected to said cylinder and communicating adjacent its breech end with said compression chamber, so that when said one piston reduces the volume of saideompression chamber the air compressed therein will drive a projectile out of said barrel; separate actuating means 'for each piston, said means jointly eiiective to permanently urge said pistons toward each other; synchronizing means'cooperative with said actuating means and operatively interconnecting said pistoward each other by the action of said actuating means and said synchronizing means whereby said pistons are adapted to obtain simultaneously the end positions of their movements toward each other. a

3. In an air gun, in combination, a cylinder; a pair of pistons slidable inwardly toward and outwardly away with respect to each other in said cylinder and at least one of said pistons forming with part of-said cylinder a compression chamber, said cylinder having between said pistons a partition which forms a'compression chamber with said one piston and the other of said pistons having a head end formed with a relatively large bore passing therethrough sothat said other piston is incapable of compressing a fluid and acts only as a balancing weight; a

barrel connected to said cylinder and communicating adjacent its breech end with said compression chamber, so that when said one piston reduces the volume of said compression chamber the air compressed therein will drive aprojectile out of. said barrel; a pair of elements engaging said pistons for movements therewith and for moving the same towards each other; and synchronizing means operatively interengaging with both said elements, providing positively actingoperative interconnection between said elements at least: during the compression stroke in such a manner that both pistons will move atthe same speed during the compression stroke and will simultaneously attain the end positions of their movements toward each other. j

4. In an air gun, in combination, a cylinder; a pair of pistons slidable in said cylinder and defining between themselves a compression chamber in said cylinder; a barrel connected -to said cylinder and communicating adjacent its breech 'end'with said compression chamber; synchronizing gear means operatively interconnecting said pistons in such a manner that movement imparted to one piston will produce equalsimultaneous movement of the other pistontherebymoving both-pistons in synchronism at all times and in both directions. I

r -5, In an air gun, in combination, a cylinder; a pair of pistons, slidable inwardly toward and outwardly away with respect 1.0 each otherin said cylinder and defining other; synchronizing me'ans coope'rativejwith said 'actuating means and operatively interconnecting said pistons-in such a manner that'thereby bothpistons will'move in synchronism at the same speed in their movement toward each other during the compression stroke; cocking means cooperatingiwith said synchronizing means for moving said pistons to the end positions of their respective outward movements awayfrom each other against the urging of said actuating means including a'safety catch member spring urged to engage said synchronizing'means for holding the pistons in said outward end positions; a breech closure member movable between breech closing and breech opening positions as well as toward and away from said safety catch member, said breech closure member being adapted when in breech closing position to disen- 'gage 's'aid catch member from said synchronizing means; and trigger means operable to release said pistons for movement synchronously toward each other by the reaction of said actuating means whereby-said pistons are adapted to attain simultaneously the end positions of their movement toward'each other.

6. In an air gun, in combination, a cylinder; a pair of pistons slidable in said cylinder and defining between themselves a compression chamber in said cylinder; a barrel connected to said cylinder and communicating adjacent its breech end with said compression chamber; means operatively connected to said pistons for compelling the same to. move at equal speeds and in opposite directions; and a partition .shiftable in said cylinder between said pistons and formed with passages communicating with said barrel adjacent said breech end thereof and with the spaces in said cylinder on opposite sides of said partition, so that the location of said partition in said cylinder is determined by said pistons.

7. In an air gun, in combination, a cylinder; a pair 0 pistons slidable in said cylinder and defining between themselves a compression chamber'in said cylinder; a barrel connected to said cylinder and communicating adjacent its breech end with said compression chamber; means operatively connected to said pistons for compelling the same to move at equal speeds and in' opposite directions; a partition shiftable in said cylinder between said pistons and formed with passages communicating with said barrel adjacent said breech end thereof'andwith the spaces in said cylinder on opposite sides of said partition, so that the location of said partition in said cylinder is determined by said pistons; and friction means carried by the periphery of said partition and engaging the inner face of said cylinder for frictionally maintaining said partition in the position to which it is moved by said pistons. p

8. In an air gun, in combination, a cylinder; a pair of pistons slidable inwardly toward and outwardly away withrespect to each other in said cylinder and at least one of said pistons forming with part of said cylinder a compression chamber; a barrel connected to said cylinder and communicating adjacent its breech end with said compression chamber, sothat when said one piston reduces the volume of said compression chamber the-air compressed therein will drive a projectile out of saidbarrel; atpair of elements engaging said pistonsfor movement therewith and for moving the same towards each other; and synchronizing means operatively interengaging with both said elements, providing positively acting operative interconnection between said elements at all times in such a manner that both pistons will move at equal speeds at all times and will simultaneously attain the end positions of their movements toward each other. 9; In an air gun, in combination, a cylinder; a pair 0 pistons slidable in said cylinder and at least one of said pistons forming with part of said cylinder a compression chamber; a barrel connected to said cylinder and communicating adjacent its breech end with said compression chamber, so that when said one piston reduces the volume of said compression chamber the air compressed therein will drive a projectile out of said barrel; and means operatively'connected to said pistons for compelling the same to move at all times at the same speed and in op- 9 posite directions, said means comprising a pair of racks fixed to said pistons and a pinion located between and meshing with said racks.

10. In an air gun, in combination, a cylinder; a pair of pistons slidable in said cylinder and at least one of said pistons forming with part of said cylinder a compression chamber; a barrel connected to said cylinder and communicating adjacent its breech end with said compression chamber, so that when said one piston reduces the volume of said compression chamber the air compressed therein will drive a projectile out of said barrel; and means operatively connected to said pistons for compelling the same to move at all times at the same speed and in opposite directions, said means comprising a pair of levers engaging said pistons, respectively, for movement therewith and for moving the same towards each other, and a pair of gear sectors fixed to said levers, respectively, and meshing with each other said gear sectors being tumable coaxially with respective levers.

11. In an air gun, in combination, a cylinder; a pair of pistons slidable in said cylinder and at least one of said pistons forming with part of said cylinder a compression chamber; a barrel connected to said cylinder and communicating adjacent its breech end with said compression chamber, so that when said one piston reduces the volume of said compression chamber the air compressed therein will drive a projectible out of said barrel; means operatively connected to said pistons for compelling the same to move at all times at the same speed and in opposite directions, said means comprising a pair of levers engaging said pistons, respectively, for movement therewith and for moving the same towards each other, and a pair of gear sectors fixed to said levers, respectively, and meshing with each other, said gear sector being turnable coaxially with respective levers; and spring means engaging said levers for acting through the latter on said pistons for urging the latter toward each other.

12. In an air gun, in combination, a cylinder; a pair of pistons slidable in said cylinder and at least one of said pistons forming with part of said cylinder a compression chamber; a barrel connected to said cylinder and communicating adjacent its breech end with said compression chamber, so that when said one piston reduces the volume of said compression chamber the air compressed therein will drive a projectile out of said barrel; means operatively connected to said pistons for compelling the same to move at all times at the same speed and in op posite directions, said means comprising a pair of racks fixed to said pistons and a pinion located between and meshing with said racks; and spring means in said cylinders engaging said pistons for urging the same toward each other.

13. In an air gun, in combination, a cylinder; a pair of pistons slidable in said cylinder and at least one of said pistons forming with part of said cylinder a compression chamber; a barrel connected to said cylinder and communicating with said compression chamber, so that when said one piston reduces the volume of said compression chamber the air compressed therein will drive a projectile out of said barrel; a pair of elements engaging said pistons for movement therewith and for moving the same towards each other; and synchronizing means operatively interengaging with both said elements, providing positively acting operative interconnection between said elements at least during the compression stroke in such a manner that both pistons will move at the same speed during the compression stroke and will simultaneously attain the end positions of their movements toward each other.

14. In an air gun, in combination, a cylinder; a pair of pistons slidable in said cylinder and at least one of said pistons forming with part of said cylinder a compression chamber; a barrel connected to said cylinder and communicating adjacent its breech end with said compression chamber, so that when said one piston reduces the volume of said compression chamber the air compressed therein will drive a projectile out of said barrel; means operatively connected to said pistons for compelling the same to move at all times at the same speed and in opposite directions, said means comprising a pair of racks fixed to said pistons and a pinion located between and meshing with said racks; and means cooperating with only one of said racks for moving said pistons to a starting position where the volume of said compression chamber is largest and for releasing said pistons to move toward each other.

15. In an air gun, in combination, a cylinder; a pair of pistons slidable in said cylinder and at least one of said pistons forming with part of said cylinder a compression chamber; a barrel connected to said cylinder and communicating adjacent its breech end with said compression chamber, so that when said one piston reduces the volume of said compression chamber the air compressed therein will drive a projectile out of said barrel; means operatively connected to said pistons for compelling the same to move at all times at the same speed and in opposite directions, said means comprising a pair of levers engaging said pistons, respectively, for movement therewith and for moving the same towards each other, and a pair of gear sectors fixed to said levers, respectively, and meshing with each other, said gear sectors being tumable coaxially with respective levers; spring means engaging said levers for acting through the latter on said pistons for urging the latter toward each other; and means cooperating with only one of said levers for moving both of said pistons to a position where the compression chamber has its largest volume.

16. In an air gun, in combination, a barrel; an air compression cylinder having communicative connection with said barrel adjacent to the breech end portion there'- of; a pair of piston means adapted to be moved toward and away with respect to each other with at least one of said pistons forming with said cylinder a compression chamber, so that when said piston means are moved toward each other, the air compressed between them will drive a projectile out of the barrel, synchronizing means operatively interconnecting said pistons in such a manner that movement imparted to one piston will produce equal simultaneous movement of the other piston so that the pistons will move in synchronism at all times; actuating means for permanently urging said pistons towards each other; cocking means for moving said pistons to the end positions of their respective movements away from each other against the urging of said actuating means; and trigger means operable to release said pistons for moving synchronously towards each other by the action of said actuating and said synchronizing means whereby said pistons are adapted to attain simultaneously the end portion of their movement toward each other.

References Cited in the file of this patent UNITED STATES PATENTS 1,978,879 Ferris et al Oct. 30, 1934 FOREIGN PATENTS 137,021 Great Britain Dec. 31, 1919 376,259 Germany May 25. 1923

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