A drill tool comprises a drive shaft ( 2 ) that is arranged to allow rotational movement to be transmitted from a drill to a drill bit holder ( 10 ) even when the opposite ends of the drive shaft are not axially aligned. The end of the drive shaft housing the drill bit holder ( 10 ) can be inserted into a guide member ( 14 ) that includes a planar element ( 18, 42 ) that is arranged to ensure that the drill bit is maintained at substantially 90° to the surface of a work piece being drilled even if the drill itself is not so aligned.
1. A hand held drill tool comprising:
a flexible drive shaft arranged to transmit rotational motion when opposing first and second ends of said drive shaft are not axially aligned; and
a guide element arranged, in use, to hold the said first end of the flexible drive shaft in a predetermined spatial relationship to a work piece to be drilled, the first end of the flexible drive shaft being connected to a drill bit holder, at the first end thereof; and
first and second drive shaft casing elements, said casing elements connected in series to each other by means of a flexible joint and substantially enclosing different portions of said flexible drive shaft.
2. A drill tool according to claim 1 , wherein said guide element further includes a resilient biasing member arranged to urge said first end of said drive shaft away from said work piece to be drilled.
3. A drill tool according to claim 1 , wherein said drill bit holder is rotatably mounted within said second drive shaft casing element.
4. A drill tool according to claim 1 , wherein said guide element comprises a first portion having a hollow passage therein arranged to receive said second drive shaft casing element, and a substantially planar element connected to said first portion so as to be substantially perpendicular thereto.
5. A drill tool according to claim 1 , wherein said drive shaft comprises first and second shaft portions connected to one another by a universal type joint.
6. A drill tool according to claim 1 , wherein said guide element comprises a first portion having a hollow passage therein arranged to receive said first end of said drive shaft and a substantially planar element connected to said first portion so as to be substantially perpendicular thereto.
7. A drill tool according to claim 4 wherein said planar element includes a bore formed therethrough axially aligned with said hollow passage of said first portion.
8. A drill tool comprising:
a flexible drive shaft arranged to transmit rotational motion when opposing first and second ends of said drive shaft are not axially aligned; and
a guide element arranged, in use, to hold the said first end of the flexible drive shaft in a predetermined spatial relationship to a work piece to be drilled, the first end of the flexible drive shaft being connected to a drill bit holder, at the first end thereof, further comprising first and second drive shaft casing elements, said casing elements being connected to one another by a flexible joint, and substantially enclosing said flexible shaft, wherein said guide element comprises a first portion having a hollow passage therein arranged to receive said second drive shaft casing element, and a substantially planar element connected to said first portion so as to be substantially perpendicular thereto, wherein said planar element includes a bore formed therethrough axially aligned with said hollow passage of said first portion, wherein a guide bush is located within said bore of said planar element, said guide bush being arranged to allow the passage of a drill bit therethrough.
9. A drill tool according to claim 1 , wherein said guide element includes at least one aperture through which swarf may be evacuated when said drill tool is in use.
10. A drill tool comprising:
a flexible drive shaft arranged to transmit rotational motion when opposing first and second ends of said drive shaft are not axially aligned; and
a guide element arranged, in use, to hold the said first end of the flexible drive shaft in a predetermined spatial relationship to a work piece to be drilled, the first end of the flexible drive shaft being connected to a drill bit holder, at the first end thereof, wherein said guide element further includes a resilient biasing member arranged to urge said first end of said drive shaft away from said work piece to be drilled.
11. A drill tool according to claim 7 , wherein a guide bush is located within said bore of said planar element, said guide bush being arranged to allow the passage of a drill bit therethrough.