Tool and chuck for hammer drill

Abstract

A hammer drill has a chuck forming a tool receptacle defining a chuck axis and provided with a tool-holding element radially displaceable into a position protruding into the tool receptacle. The tool has a shank defining a tool axis receivable axially in the receptacle. This shank is formed with a radially outwardly opening recess closed at both axial ends and shaped to receive the tool-holding element, and with an axially extending groove separate from the recess and opening axially at the end of the shank. This groove has at least one flank extending substantially radially of the tool axis. A rotary-entrainment formation in the receptacle is formed with at least one side flatly engageable with the flank for maximum force transmission and minimum wear.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims: 
     
       1. In a combination with a chuck having a tool receptacle defining a chuck axis, a rotary and impact tool having a shank defining a tool axis and receivable in said receptacle; cooperating means on said shank and said receptacle for retaining said tool in said receptacle against extraction therefrom while permitting axial displacement of the tool relative to the receptacle so that the tool can transmit axial impact to a workpiece; and means separate from said cooperating means and operative for transmitting torque between said chuck and said tool, including an axially extending groove separate and circumferentially spaced from said cooperating means, said groove being axially open at the end of said shank and having at least one flank extending substantially radially of said tool axis, said torque transmitting means further including a rotary-entrainment formation in said receptacle formed with at least one side flatly engageable with said flank. 
     
     
       2. The combination defined in claim 1 wherein said groove has a pair of such flanks both being coplanar with said tool axis. 
     
     
       3. The combination defined in claim 2 wherein said formation has an axial length substantially equal to the axial length of said groove. 
     
     
       4. The combination as defined in claim 1, wherein said cooperating means includes a radially outwardly opening recess formed in said shank and closed at both axial ends of said recess, and a tool-holding element radially displaceable into a position protruding into said receptacle so as to be received into said recess. 
     
     
       5. The combination defined in claim 4 wherein said shank is of regular section, said recess extending circumferentially completely around said shank and through said groove. 
     
     
       6. The combination defined in claim 4 wherein said shank is generally cylindrical and has a predetermined diameter, said groove having a radial depth equal to between three-twentieths and one-quarter of said diameter. 
     
     
       7. The combination defined in claim 4 wherein said groove and said recess lie on diametrically opposite sides of said tool axis. 
     
     
       8. The combination defined in claim 4 wherein said tool-holding element has a round inner end and said recess is similarly of rounded shape complementary to that of said inner end. 
     
     
       9. The combination defined in claim 4 wherein said shank is formed with two such recesses on diagonally opposite sides and with two such grooves also on diagonally opposite sides but angularly offset from said recesses. 
     
     
       10. The combination defined in claim 9 wherein said grooves are offset angularly relative to said tool axis from said recesses by between 45° and 90°. 
     
     
       11. The combination defined in claim 1 wherein said groove is of prismatic shape. 
     
     
       12. The combination defined in claim 11 wherein said shank has two such grooves on diagonally opposite sides. 
     
     
       13. The combination defined in claim 11 wherein said recess is of part-cylindrical shape and said groove is formed in the base of said recess. 
     
     
       14. In a power tool, a combination comprising a chuck having a tool receptacle defining a chuck axis; a rotary and impact tool having a shank defining a tool axis and being receivable in said receptacle; cooperating means on said shank and said receptacle for retaining said tool in said receptacle against extraction therefrom while permitting axial displacement of the tool relative to the receptacle so that the tool can transmit axial impact to a workpiece; and means separate from said cooperating means and operative for transmitting torque between said chuck and said tool, including an axially extending groove separate and circumferentially spaced from said cooperating means, said groove being axially open at the end of said shank and having at least one flank extending substantially radially of said tool axis, said means further including a rotary-entrainment formation in said receptacle formed with at least one side flatly engageable with said flank. .Iadd. 
     
     
       15.  A rotary and impact tool for the use with a chuck having a tool receptacle, a first formation in the receptacle and a projection in the receptacle separate from the first formation, the tool comprising a shank defining a tool axis; a second formation on said shank and cooperating with the first formation of the chuck so as to form together cooperating means for retaining the tool in the receptacle of the chuck against extraction therefrom while permitting axial displacement of the tool relative to the receptacle whereby the tool can transmit axial impact to a workpiece; and an additional formation on said shank and formed as an axially extending groove which is separate and circumferentially spaced from said second formation, said groove being axially open at the end of said shank and having at least one flank extending substantially radially of said tool axis so that the projection of the chuck can engage in said groove and at least one side of the projection can flatly engage with said one flank, whereby said groove of said shank and the projection of the chuck together form means which is separate from the cooperating means and operative for transmitting torque between the chuck and the tool. .Iaddend. .Iadd. 
     
     
       16.  A rotary and impact tool as defined in claim 15, wherein said second formation of said shank is arranged so that it is in direct contact with the first formation of the receptacle of the chuck without interposition of additional means. .Iaddend. .Iadd.17. A rotary and impact tool as defined in claim 15, wherein said one flank of said groove of said shank is arranged so that it is in direct contact with the projection of the chuck without interposition of additional means. .Iaddend. .Iadd.18. A rotary and impact tool as defined in claim 15, wherein said second formation of said shank is formed as a concave recess which is closed at both its axial ends. .Iaddend. .Iadd.19. A rotary and impact tool as defined in claim 15, wherein said second formation of said shank is formed as a recess having a part-cylindrical cross section and two part-spherical axial ends. .Iaddend. .Iadd.20. A rotary and impact tool comprising a shank defining a tool axis; a formation on said shank allowing limited axial displacement of said shank so that the tool can transmit axial impact to a workpiece and at the same time preventing complete axial extraction of said shank from a holding structure; and an additional formation on said shank and formed as an axially extending groove which is separate and circumferentially spaced from said first-mentioned formation, said groove being axially open at the end of said shank, having at least one flank extending substantially radially of said tool axis and being operative for transmitting torque to said shank. .Iaddend. .Iadd.21. A rotary and impact tool as defined in claim 20, wherein said first-mentioned formation on said shank is formed as a concave recess 
     
     
        which is closed at both its axial ends. .Iaddend. .Iadd.22.  A rotary and impact tool as defined in claim 20, wherein said first-mentioned formation on said shank is formed as a recess having a part-cylindrical cross section and two part-spherical axial ends. .Iaddend.