Abstract:
The application discloses an explosive-cartridge powered hammer or impact tool, which is especially adapted for use in foundries for trimming or finishing castings by knocking off runners, feeder heads and flash, but which can also be used for other operations, such as riveting. The hammer is provided with means to soften recoil.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application corresponds to the inventor&#39;s application No. 76.04229, filed in France on Feb. 9, 1976. The rights of priority under 35 U.S.C. 119 are claimed. 
     BRIEF SUMMARY 
     The removal of runners, feeder heads and flash from castings in the foundry presents a number of well known problems. 
     Frequently, manual labor is used to remove excess metal by striking it off the casting by use of a sledge. This work is laborious and production is low. 
     Complex machines are also used for the removal of excess metal, but sometimes do not easily remove the excess metal from the casting. 
     To remedy these drawbacks, the instant invention has been developed. It is an explosive-cartridge powered hammer or impact tool. The device has a cartridge magazine, cartridge feeding device, a breech to receive the cartridge, a hammer to fire the cartridge, a barrel, a massive gas-driven piston on which is mounted an impact head and damping means to soften the recoil of the gun. 
    
    
     VIEWS OF DRAWING 
     FIG. 1 is a small scale external side view of an explosive-powered hammer or impact device, in accordance with the invention. 
     FIG. 2 is an external plan view corresponding to FIG. 1. 
     FIG. 3 is a longitudinal sectional view of the hammer with the breech in the open position and with the piston in its rearward position. 
     FIG. 4 is a longitudinal sectional plan view along the line 4--4 of FIG. 3. 
     FIG. 5 is a partial longitudinal cross section of the hammer with the breech in a closed position and with the piston in its forward position. 
     FIG. 6 is a cross-sectional profile view along the line 6--6 of FIG. 5. 
     FIG. 7 is a side view in cross-section along the line 7--7 of FIG. 5. 
     FIG. 8 is a cross-sectional view along the line 8--8 of FIG. 5. 
    
    
     DETAILED DESCRIPTION 
     To secure the objects of the invention, without limiting the same except as defined in the claims, reference is made to the drawings, which illustrate a preferred embodiment. 
     The split frame 1 of the hammer carries a breech sleeve 4 and barrel sleeve 5, the latter two being connected by breech member 9, which has a flange 9 1 . Barrel sleeve 5 is screwed onto the front portion of the breech member 9, while breech sleeve 4 is pinned to the reduced diameter portion 9 2  of the breech member 9, as can be seen in the drawing. On either side of the flange 9 1 , and within the split frame 1, are situated damping rings 2 and 3. A trigger d controls a camming member 6. Cartridges c are received from magazine 7, which is held in the grip by retainer 8. 
     It is evident that the feeding of cartridges can be achieved by completely different means, well known in the revolver and machine pistol art. 
     The shouldered breech member 9 permits, by the use of flange 9 1 , and the damping rings 2 and 3, a soft resilient positioning of the gun within the frame 1, thereby reducing recoil in the grip. The axial bore of the breech member 9 holds the cartridge c during firing. 
     The after end of the breech sleeve 4 has a cylindrical bore which receives the longitudinally movable cylindrical bolt 10, which carries a firing hammer mechanism 11 having at its front end 11 1  a pin for hitting the percussion cap of the cartridge. The firing mechanism 11 includes a detent 11 2  which cooperates with sear 12 and camming member 6, connected to the trigger. 
     The rear part of the bolt 10 is of reduced diameter and carries a rotatable thumb cocking piece 13, which is held in position by retainer 14. The inner part of retainer 14 allows the centering of a guiding rod 15 on which is strung a compression spring 16 which bears against firing hammer 11 and drives it against cartridge c when the sear 12 and detent 11 2  are not engaged. 
     The rotatable thumb cocking piece has at its fore portion a threaded section 13 1  which is screwed into the rear end of breech sleeve 4 in order to close and lock the bolt securely against the cartridge c, when the cartridge is to be fired. 
     These various parts, adequate for the proper operation of the pistol, are described only as an example, since they are well known in the technology. It is evident that completely different devices could be employed for cocking and locking the bolt. 
     The barrel sleeve 5 receives in its bore a piston 17, having an extreme rear end of greatly reduced diameter which forms a piston rod 17 1  which slides in the bore 9 4  (FIG. 5) of the fore part of breech member 9, which bore communicates in turn with the chamber 9 3  in which cartridge c is fired. 
     Thereby the thrust exercised by the firing is applied axially to the piston rod 17 1  of 17. The piston 17 is guided in its forward motion by flange 17 2  while sliding inside barrel sleeve 5. 
     The piston 17 carries the reduced diameter impacting head 17 3  at its fire end. 
     A cap 18 is screwed onto the front extremity of barrel sleeve 5. Cap 18 has a concentric axial bore 18 1  which guides, during firing, the reduced diameter impact head 17 3 . 
     Resilient washer 19 is freely and slidably mounted on the reduced diameter impact head 17 3  and inside barrel sleeve 5. The washer is deformed radially when it is compressed axially between cap 18 and flange 17 2  as the impact head 17 3  moves all the way forward. The forward motion of the impact head 17 3  is stopped gently by the said compressing. 
     Moreover, washer 19 is designed to be supported and held for perfect alignment and tightness by use of a conical tip 19 1  (FIG. 3) which corresponds in shape to the complemental recess 17 4  in the front face of the cylindrical face of flange 17 2 . 
     Means for holding the piston 17 in retracted position, ready to be fired, include one or a plurality of detents. In FIG. 5 there is shown a ball detent 20 sliding loosely in hole 17 5  in flange 17 2 . The ball detent 20 is spring biased radially outwardly by compression spring 21. The ball detent, under the elastic pressure of compression spring 21, cooperates with the circular groove 5 1  in the inner wall of barrel sleeve 5. 
     It will thus be evident that the ball detent 20 holds the piston 17 in its rearward position, against unintended forward motion caused by ordinary handling of the explosive-cartridge powered hammer, until such time as the trigger d is squeezed to fire the cartridge c. To achieve this result the compression spring 21 is of such size as to exert a suitable outward force on ball 20. 
     As illustrated in FIG. 3 of the drawing, the axial opening 18 1  of cap 18 is provided with a seal J, which cooperates with the outer surface of the reduced diameter impact head 17 3  to form an air tight chamber when the cartridge c is fired. At that time, the air in the chamber is compressed. After the impact head 17 3  has struck its blow, the compressed air reexpands and drives the impact head 17 3  back to a retracted position. 
     The withdrawal of hammer 17 to its retracted position can also be accomplished by rebound of the impact head 17 3  from the workpiece or by manually pushing the protruding impact head 17 3 . 
     Other suitable means can be used to retract the impact head 17 3 , such as spring means, means powered by the gases from the spent cartridge c or by the use of compressed air supplied from an air line. 
     Release of trapped air or the burnt gases from the cartridge c is accomplished by the vent hole 5 2  (FIG. 6) in the front section of the barrel sleeve 5, and by the vent holes 5 3  and 5 4  in the rear section of the barrel sleeve. Each vent hole 5 2 , 5 3  and 5 4  is provided with a silencer 22 for the escape of the air or the gases. 
     As illustrated in FIG. 8, the breech sleeve 4 is provided with two safety vents 4 1  and 4 2 . 
     It is to be noted that a supporting collar 23 is removably mounted on the barrel sleeve 5 to allow the attachment of a handle 24 and a suspension ring 25. 
     In the illustrated example, the piston 17 has a reduced diameter immediately behind the flange 17 2 . Without departing from the invention, the diameter of that portion of piston 17 could be increased to the diameter of the flange 17 2 , with corresponding increase of size of part of the barrel sleeve 5. This would increase the weight of the piston 17 and increase the force of the blow. 
     It is evident that this explosive-cartridge powered hammer or impact tool may be utilized in other procedures where a blow by a hammer is sought. For example: in riveting operations, or for the breaking up of work pieces by applying blows. 
     The advantages can be noted from the description while particularly emphasizing: 
     the simplicity of the construction, 
     extreme force of the blow. 
     The invention is not limited to the specific form just described, but is defined by the following claims: