Drill bit for a percussive hammer and shank therefore

Patent metadata

Field	Value
Publication number	US-9719306-B2
Application number	US-201214371017-A
Country	US
Kind code	B2
Filing date	Dec 7, 2012
Priority date	Jan 9, 2012
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

A bit for a percussive hammer includes an elongated shank, a head at a first end of the shank, and an array of lengthwise extending spline portions defining outwardly extending retention lugs at or toward a further end of the shank. At least a side face of at least one lug is blended into the shank of the bit.

First claim

The invention claimed is:

1. A drill bit for a percussive hammer comprising:
an elongated shank having opposed ends;
a head disposed at a first end of the shank;
an array of lengthwise extending spline portions defining outwardly extending retention lugs at or toward a second end of the shank, each of the retention lugs having opposed side faces, a top land and first and second end faces, at least one side face of at least one lug of the retention splines being blended into the shank of the bit, and each of the first and second end faces of each retention lug is blended into the top land; and
a plurality of lengthwise extending driven splines longitudinally spaced from the array of retention lugs located toward the head end of the bit, each of the driven splines having a top land perceptibly wider than the top land of each lug of the retention splines.

2. The bit of claim 1 , wherein each retention lug of the spline portions includes a pair of side faces, each of the side faces being blended into the shank of the bit.

3. The bit of claim 1 , wherein each of the first and second end faces of each retention lug of the spline portions is blended into the shank of the bit.

4. The bit of claim 3 , wherein each retention lug face blended into the shank is blended by a single and continuous concave easing or fillet extending between an edge of the top land and the shank.

5. The bit of claim 4 , wherein the concave easing or fillet of each side face is perceptibly wider than the top land of each retention lug.

6. The bit of claim 1 , wherein each of the first and second retention lug end faces blended into the top land of the retention lug is blended by a convex easing or round extending between the face and the top land.

7. A shank of a drill bit for a percussive hammer having a head at a first end of the shank, said shank comprising:
an array of lengthwise extending spline portions defining outwardly extending retention lugs at or toward a further end of the shank, each of the retention lugs having opposed side faces, a top land and first and second end faces, at least one side face of at least one retention lug of the spline portions blending into the shank and each of the first and second end faces of each retention lug being blended into the top land; and
a plurality of lengthwise extending driven splines longitudinally spaced from the array of spline portions disposed toward the head at a first end of the shank, each of the driven spline having a top land which is perceptibly wider than the top land of each retention lug.

Assignees

• Sandvik Intellectual Property

Inventors

• Seppala Conny
• Jansson Tomas Sh

Classifications

• E21B10/36 Primary

  Percussion drill bits ({with helical conveying portion E21B10/445;} characterised by wear resisting parts E21B10/46) · CPC title

• E21B17/076

  between rod or pipe and drill bit · CPC title