Electric nailer

Abstract

An automatic nailing device employs a cartridge of nails which are supplied in series beneath a spring driven hammer. An electric motor charges the spring-driven hammer after each operation.

I claim: 
     
       1. An electrically operable portable nailing device comprising, in combination: elongated axially movable hammer means;   energy storage spring means connected to said hammer means for delivering operating force to said hammer means;   latch means for latching said energy storage means in a stored energy condition;   trigger means for defeating said latch means to permit said energy storage spring means to operate said hammer means;   nail delivery means for delivering nails to be driven to said hammer means;   an electrical motor, and a spring charging mechanism for coupling said electrical motor to said energy storage spring means to enable charging of said energy storage spring means when said latch means is defeated; said spring charging mechanism including a rotating sleeve having a plurality of charging balls trapped therein, and wherein said elongated hammer means includes an externally threaded region engageable by said charging balls, whereby rotation of said sleeve causes said balls to drive said hammer means in a spring charging direction.   
     
     
       2. The device of claim 1 which further includes a second sleeve concentric with said rotating sleeve; said second sleeve having an inner annular recess and being axially movable from a position pressing said balls into engagement with said threaded region to a position allowing said balls to move into said annular recess and out of engagement with said threaded region. 
     
     
       3. The device of claim 2 wherein said second sleeve is operatively connected to said trigger means and is moved to said position pressing said balls into said threaded region after said trigger means is released. 
     
     
       4. The device of claim 1 which further includes a plurality of latching balls and wherein said elongated hammer means includes a latching shoulder engageable by said latching balls; said latching balls latching under said latching shoulder after said energy storage spring means is fully charged. 
     
     
       5. The device of claim 4 which further includes a latching sleeve disposed concentrically about said rotating sleeve and being axially movable to hold said latching balls under said shoulder, and to release said latching balls; said latching sleeve being operatively connected to said trigger means and being moved to release said latching balls when said trigger means is operated. 
     
     
       6. The device of claim 2 which further includes a plurality of latching balls and wherein said elongated hammer means includes a latching shoulder engageable by said latching balls; said latching balls latching under said latching shoulder after said energy storage spring means is fully charged. 
     
     
       7. The device of claim 3 which further includes a plurality of latching balls and wherein said elongated hammer means includes a latching shoulder engageable by said latching balls; said latching balls being trapped in said rotating sleeve, whereby said latching balls latch under said latching shoulder after said energy storage spring means is fully charged. 
     
     
       8. The device of claim 6 which further includes a latching sleeve disposed concentrically about said rotating sleeve and being axially movable to hold said latching balls under said shoulder, and to release said latching balls; said latching sleeve being operatively connected to said trigger means and being moved to release said latching balls when said trigger means is operated. 
     
     
       9. The device of claim 7 which further includes a latching sleeve disposed concentrically about said rotating sleeve and being axially movable to hold said latching balls under said shoulder, and to release said latching balls; said latching sleeve being operatively connected to said trigger means and being moved to release said latching balls when said trigger means is operated. 
     
     
       10. An electrically operable impact device comprising, in combination:  elongated axially movable hammer means;   energy storage spring means connected to said hammer means for delivering operating force to said hammer means;   latch means for latching said energy storage means in a stored energy condition;   trigger means for defeating said latch means to permit said energy storage spring means to operate said hammer means;   an electrical motor, and a spring charging mechanism for coupling said electrical motor to said energy storage spring means to enable charging of said energy storage spring means when said latch means is defeated; said spring charging mechanism including a rotating sleeve having a plurality of charging balls trapped therein, and wherein said elongated hammer means includes an externally threaded region engageable by said charging balls, whereby rotation of said sleeve causes said balls to drive said hammer means in a spring charging direction.   
     
     
       11. The device of claim 10 which further includes a second sleeve concentric with said rotating sleeve; said second sleeve having an inner annular recess and being axially movable from a position pressing said balls into engagement with said threaded region to a position allowing said balls to move into said annular recess and out of engagement with said threaded region. .Iadd. 12. An electrically operable portable hammer device comprising, in combination: elongated axially movable hammer means;   energy storage means connected to said hammer means for delivering operating force to said hammer means;   an electrical motor, and a charging mechanism for coupling said electrical motor to said energy storage means to enable charging of said energy storage means to a predetermined charged condition, said charging mechanism including a rotating sleeve having a plurality of charging balls trapped therein, and   wherein said elongated hammer means includes a threaded region engageable by said charging balls, whereby rotation of said sleeve causes said balls to drive said hammer means to change the energy storage means to said predetermined charged condition;   latch means for latching said energy storage means in said predetermined position; and   trigger means for defeating said latch means to permit said energy storage means to operate said hammer means. .Iaddend..Iadd. 13. The device of claim 12 which further includes a second sleeve concentric with said rotating sleeve; said second sleeve having an inner annular recess and being axially movable from a position pressing said balls into engagement with said threaded region to a position allowing said balls to move into said annular recess and out of engagement with said threaded region. .Iaddend..Iadd. 14. The device of claim 12 which further includes a plurality of latching balls and wherein said elongated hammer means includes a latching shoulder engageable by said latching balls; said latching balls latching under said latching shoulder when said energy storage means is in said predetermined charged condition. .Iaddend. .Iadd. 15. The device of claim 14 which further includes a latching sleeve disposed concentrically about said rotating sleeve and being axially movable to hold said latching balls under said shoulder, and to release said latching balls; said latching sleeve being operatively connected to said trigger means and being moved to release said latching balls when said trigger means is operated. .Iaddend.