Abstract:
A tool is provided with a barrel having a piston for driving a fastener into a substrate, the barrel being mounted for axial movement within a body of the tool and a nose piece being mounted forwardly of the barrel and being at least partially encapsulated by a base plate that connects to the receiver of the tool which encloses the barrel and piston, the present invention permiting ease of assembly and disassembly of the muzzle of the tool—the nose piece and base plate—by making the connection between the base plate and the receiver with a retainer element.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to a power actuated fastening tool for driving a fastener, such as a nail, into a substrate, such as a concrete or steel structure. 
         [0002]    Power actuated tools for driving a fastener into a substrate conventionally comprise a barrel from which the fastener is expelled by means of a piston driven by detonation of an explosive charge. The barrel is mounted for axial movement within a receiver assembly which is in turn in the housingor body of the tool. A nose piece is placed forwardly of the barrel and received partially therein and is exposed outside of the housing. A base plate encapsulates most of the nose piece and the forward end of the barrel and attaches to the receiver. 
         [0003]    It is necessary to periodically disassemble the tool, particular the muzzle and barrel components for cleaning purposes and replacement of the returner which is generally made of rubber and wears out through repeated use, which requires removal of the base plate and nose piece so that the user can access the barrel, piston and returner. Disassembly can be difficult due to carbon dust build up on the components of the tool. Carbon build-up on fine threaded connections can be particularly troublesome, jamming the connection and making it very difficult to unscrew the base plate from the housing or receiver of the tool. The disassembly and subsequent reassembly, if difficult, can also use up time that can be more productively spent. 
       SUMMARY OF THE INVENTION 
       [0004]    According to the present invention, there is provided a tool comprising a barrel having a piston for driving a fastener into a substrate, the barrel being mounted for axial movement within a body of the tool and a nose piece being mounted forwardly of the barrel and being at least partially encapsulated by a base plate that connects to the receiver of the tool which encloses the barrel and piston, the present invention permiting ease of assembly and disassembly of the muzzle of the tool—the nose piece and base plate—by means of the connection between the base plate and the receiver. 
         [0005]    In a preferred embodiment of the invention a retainer element is carried by the receiver and engages a transverse track on the base plate to cause entrainment of the receiver when the base plate is received in the receiver. 
         [0006]    According to another aspect of the present invention, there is provided a power actuated tool for driving a fastener into a substrate upon detonation of an explosive charge, said tool having a barrel and a nose plates placed forwardly of the barrel and both members being retained in the tool by means of a base plate connected to the housing, the base plate being held in assembled relation to the housing by a retainer element and being such that assembly and disassembly can occur by a simple manipulation of the base plate relative to the receiver. 
         [0007]    In the preferred embodiment, a latch is provided such that when the base plate and the receiver are connected they are prevented from further rotation until the latch is released. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0008]      FIG. 1  is a schematic view, showing the barrel, the housing, the receiver, the piston, the rubber retainer, the nose plate and the base plate of a tool in disassembled relation. 
           [0009]      FIG. 2  is a partial cross-section, side view showing the barrel, the housing, the receiver, the piston, the rubber retainer, the nose plate and the base plate in disassembled relation. 
           [0010]      FIG. 3  is a partial cross-section, side view, showing the barrel, the housing, the piston, the rubber retainer, the receiver, the nose plate and the base plate in assembled relation. 
           [0011]      FIG. 4  is a schematic view of another embodiment of the present invention, showing the barrel, the housing, the receiver, the piston, the rubber retainer, the nose plate and the base plate of a tool in disassembled relation. 
           [0012]      FIG. 5  is a partial cross-section, side view of the alternate embodiment of  FIG. 4 , showing the barrel, the housing, the receiver, the piston, the rubber retainer, the nose plate and the base plate in disassembled relation. 
           [0013]      FIG. 6  is a schematic view of another embodiment of the present invention, showing the barrel, the housing, the receiver, the piston, the rubber retainer, the nose plate and the base plate of a tool in disassembled relation. 
           [0014]      FIG. 7  is a partial cross-section, side view of the alternate embodiment of  FIG. 6 , showing the barrel, the housing, the receiver, the piston, the rubber retainer, the nose plate and the base plate in disassembled relation. 
           [0015]      FIG. 8  is a partial cross-section, side view of the alternate embodiment of  FIG. 6 , showing the barrel, the housing, the piston, the rubber retainer, the receiver, the nose plate and the base plate in assembled relation. 
           [0016]      FIG. 9  is a schematic view of another embodiment of the present invention, showing the barrel, the housing, the receive, the piston the nose piece and the base plate in disassembled relation with the base plate-having a magazine. 
           [0017]      FIG. 10  is a schematic view of a tool incorporating the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    As shown in  FIG. 10 , the tool  100  has a handle housing  1 , with a connecting ring  2 . A two-part cylindrical receiver  3  is inserted into the housing  1  and is fixed within the housing  1 . The receiver also receives a regulator bolt  20  and a regulator nut  21 . A regulator shock absorber assembly  12  is attached to the receiver  3  where the receiver  3  interfaces with a cylindrical barrel  4 . The barrel  4  is provided with an advance lever  10  that is restrained by an advance lever spring  11 . The cylindrical piston  7  is inserted into the barrel  4 . A rubber returner  8  fits over the length of the piston  7  and is surmounted by a cylindrical nose piece  6 , which slides over the piston  7 . A baseplate  5  fits over and restrains the nose piece  6 , returner  8 , piston  7  and barrel  4 . The interiorily-threaded baseplate  5  is screwed onto the connecting ring  2 . A firing pin assembly is inserted into the housing  1  behind the receiver  3 . The firing pin assembly includes a cylindrical firing pin mechanism  14 , which contains a firing pin  13 , a firing pin sear  15 , a firing pin sear spring  16  and pushing pin  31 . A mechanism spring  17  surrounds the firing pin  13  behind the firing pin mechanism  14  and a firing pin spring  18  is behind the firing pin  13 . A receiver plug  19  restrains the firing pin assembly behind the receiver  3  and the plug  19  is covered by a plug cover  24 . The firing pin assembly is connected to a trigger  25 . The trigger  25  interfaces with a trigger sear lever  22 , which is fastened with a trigger lever pin  23 . The housing  1  is provided with a rubber handle  33  that is fastened with a bolt  28 , preferably M 6 × 15 , and a matching nut  30 , preferably M 6 . The housing  1  is closed with a screw  27 , preferably D 3 × 16 , a bolt  29 , preferably D 3 × 22 , and a bolt  32 , preferably D 3 × 35 . 
         [0019]    As shown in  FIG. 1 , a power actuated tool  1  in accordance with the invention comprises a barrel  4  which house a piston  7  the forward portion of which forms a driving pin for driving a fastener  200 . The rear end of the barrel  4  acts to receive an explosive charge which, on detonation, propels the piston  7  forwardly within the barrel  4  in order to discharge into a work surface a fastener  200  held within the nose piece  6  at the front of the barrel  4 . 
         [0020]    As shown in  FIG. 1 , in the preferred embodiment, the base plate  5  and the receiver  3  of the tool  1  are held in their assembled relationship by retainer elements in the form of pins  40 . The retainer pins  14  are preferably mounted at the front end of the receiver  3  and lie on the inner surface  41  of the receiver  3 . In the preferred embodiment, the three pins  40  are spaced equally around the circumference of the inner surface  41  of the receiver  3 . 
         [0021]    When connected, each of the pins  40  engages in a separate transverse track defined by a groove  42  formed on the outer surface  43  of the base plate  5 . 
         [0022]    Entry of each pin  40  into its associated transverse track  42  on assembly of the base plate  5  to the receiver  3  and removal of the pin  40  upon disassembly of the base plate  5  from the receiver  3  occurs via an axial slot in the form of a grove  44  opening into the transverse track or groove  42 . 
         [0023]    In the preferred embodiment shown in  FIG. 1 , each transverse groove  42  opens into an axial slot  44  in the outer surface  43  of the base plate  5 . 
         [0024]    Assembly of the base plate  5  to the receiver  3  is effected simply by inserting the base plate  5  into the front end of the receiver  3  with the base plate  5  and the receiver  3  angularly aligned so that the three retainer pins  40  will enter axial slots  44  in the base plate  5 , and the base plate  5  is pushed forwardly until the transverse grooves  42  reach the position of the three retainer pins  40  at which point the base plate is rotated such that the pins  40  are moved out of axial alignment with the axial slots  44  and are retained from further axial movement by the walls of the transverse grooves  42 . When the base plate  5  and the receiver  3  are connected by engagement of the retainer  40  in the transverse track  42 , only very limited axial movement of the base plate  5  with respect to the receiver  3  is possible without there also being rotational movement of the receiver  3  with respect to the base plate  5 , providing a secure enclosure for the barrel  4  contained therein. 
         [0025]    Disassembly of the two barrel sections is effected by the reverse action. It will thus be appreciated that disassembly and subsequent reassembly of the base plate  5  to the receiver  3  as may be periodically required for cleaning purposes is effected by simple axial and rotational movement of base plate  5  relative to the receiver  3 . 
         [0026]    In the embodiment shown in  FIG. 6 , the retainer is multi-start threads  50  located on the inner surface  51  of the base plate  5 , and the multi-start threads  51  interface with transverse slots  52  on the outer surface  53  of the receiver  3 . The multi-start threads  50  provide a quick connection between the base plate  5  and the receiver  3  given a small angular rotation between the base plate  5  and the receiver  3 . It is preferable that the rotation be less than 360 degrees. 
         [0027]    The multi start threads  51  could also be mounted on the outer surface  43  of the base plate  5 , and the transverse slots  52  that mate with them could be mounted on the inner surface  41  of the receiver  3 . Similarly, the multi-start threads  51  could also be mounted on the outer surface  53  of the receiver  3 , and the transverse slots  52  that mate with them could be mounted on the inner surface  51  of the base plate  5 . Similarly, the multi-start threads  51  could also be mounted on the inner surface  41  of the receiver  3 , and the transverse slots  52  could be mounted on the outer surface  43  of the base plate. 
         [0028]    Similar to the embodiment shown in  FIG. 6 , pins  40  could be mounted on the inner surface  41  of the base plate  5 , and the transverse track  42  with connecting axial slot  44  could be mounted on the outer surface  53  of the receiver  3 . 
         [0029]    Also similarly, and as partially shown in  FIG. 9 , pins  40  could be mounted on the outer surface  53  of the receiver  3 , and the transverse track  43  with connecting axial slot  44  could be mounted on the inner surface  51  of the base plate  5 . 
         [0030]    As shown in  FIG. 4 , openings  70  can be formed in the base plate  5  for exhausting gas, and openings  71  can be formed in the barrel  4  for exhausting gas. 
         [0031]    As is shown in  FIG. 4 , the receiver  3  which receives the barrel  4  can be made up of multiple parts. In the embodiment shown in  FIG. 4 , the receiver  3  has an outer adapter  73  and base  74 . The outer adapter, in this embodiment, is threaded onto the base  74 . 
         [0032]    As is also shown in  FIG. 4 , the connecting ring  2  is used to keep the base plate  5  from rotating with respect to the retainer  3 , or with the retainer  3  shown in  FIGS. 4 and 5 , the connecting ring keeps the outer adapter  73  of the retainer  3  from rotating with respect to the base  74  of the retainer  3 . 
         [0033]    As shown in  FIG. 9 , the base plate  6  can be formed with a magazine  76  for carrying multiple fasteners  200 , or a magazine could be attached to the base plate  5 . 
         [0034]    In addition to the quick-connecting baseplate  5  (which eliminates problems with the baseplate threads being clogged with carbon deposits), the preferred embodiment of the tool  100  of the preferred embodiment also includes a free-floating nosepiece  6 . 
         [0035]    In the preferred embodiment, the base plate  5  and nose piece are made from a heat-treated, low allow steel 42CRmo4 that conforms or closely conforms to the following standards: DIN 1.7225, AISA 4340 and UNDS G43400. BASF provides such a steel under the identifier Catamold 4340. 
         [0036]    As shown in  FIGS. 1 and 6 , in the preferred embodiment a latch  80  can connect to an indent  81  or notch to prevent relative rotation between the base plate  5  and the receiver  3  once they are connected. As shown in  FIG. 1 , the latch  80  is mounted on the receiver  3 . As shown in  FIG. 4 , the latch  80  is mounted on the base plate  5 . 
         [0037]    As shown in  FIG. 1 , in the preferred embodiment the outer surface  43  of the base plate  5  where the retainer  40  is received closely matches the inner surface  41  of the receiver  3 . 
         [0038]    Similarly, as shown in  FIG. 6 , when the base plate  5  is received over the receiver  3 , the inner surface  51  of the base plate  5  where the retainer  50  is places closely matches the outer surface  53  of the receiver  3  where the retainer will be entrained. 
         [0039]    In the preferred embodiment the end of the nose piece  6  is formed with a groove  90  at its end  91  for receiving the end of the returner  8 . 
         [0040]    In the preferred embodiment, the tool  100  is a power actuated tool, but the piston  7  could be operated by other means, such as a outside source of pressurized liquid or air, or motor that drives the piston  7 .