US3841418A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hammer drills
Assignee: Impex Essen Vertrieb von Werkzeugen GmbH
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Filing: 1972-12-15
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Granted: 1974-10-15
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Expires: 1992-12-15
Abstract
Abstract A hammer drill has a spindle for receiving the stem of a drilling tool. The spindle is rotatably driven by a drive shaft arranged parallel thereto and has a striker adapted to move into the spindle and strike the drilling tool disposed therein. The striker is cyclically withdrawn in opposition to a spring and released into striking engagement with the drilling tool disposed in the spindle by means of a ballistic cam mounted on the drive shaft. Upon removal of a drilling tool from a workpiece, the striker mechanism is deactivated.
Inventors
- 👤 H Biersack
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:17
CPC Classifications
B; B25; B25D; B25D11/00; B25D11/005; B25D16/00; B25D2211/00; B25D2211/06; B25D2211/062
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
165 words
A hammer drill having a hollow spindle for receiving a drilling tool, a drive shaft arranged to rotate the spindle and extending parrallel thereto, a striker member receivable in the spindle, and a ballistic cam on the drive shaft arranged to be rotated thereby to cause the striker member to be cyclically withdrawn against a spring and released to effect a striking action; the striker member being arranged to advance beyond the normal striking position on removal of the tool from a workpiece and thereby prevent rotation of the ballistic cam; said ballistic cam being rotatable and axially displaceable on the drive shaft and urged by a second spring towards coupling engagement with a coupling member having clutch dogs and said ballistic cam having sides inclined at an angle to a plane transverse to the drive shaft greater than the angle between the plane and surfaces of the ballistic cam and of the striker member which slidably engage during the withdrawal of the striker member.
Claim 2
Dependent Claim
165 words
A hammer drill having a hollow spindle for receiving a drilling tool, a drive shaft arranged to rotate the spindle and extending parrallel thereto, a striker member receivable in the spindle, and a ballistic cam on the drive shaft arranged to be rotated thereby to cause the striker member to be cyclically withdrawn against a spring and released to effect a striking action; the striker member being arranged to advance beyond the normal striking position on removal of the tool from a workpiece and thereby prevent rotation of the ballistic cam; said ballistic cam being rotatable and axially displaceable on the drive shaft and urged by a second spring towards coupling engagement with a coupling member having clutch dogs and said ballistic cam having sides inclined at an angle to a plane transverse to the drive shaft greater than the angle between the plane and surfaces of the ballistic cam and of the striker member which slidably engage during the withdrawal of the striker member.
Claim 3
Dependent Claim
217 words
A hammer drill having a hollow spindle for receiving a drilling tool, a drive shaft arranged to rotate the spindle and exteNding parallel thereto, a striker member receivable in the spindle, and a ballistic cam on the drive shaft arranged to be rotated thereby to cause the striker member to be cyclically withdrawn against a spring and released to effect a striking action, the striker member being arranged to advance beyond the normal striking position on removal of the tool from a workpiece and thereby prevent rotation of the ballistic cam; said ballistic cam being rotatable and axially displaceable on the drive shaft and urged by a second spring towards coupling engagement with a coupling member mounted to rotate with the drive shaft; said coupling member having clutch dogs and said ballistic cam having sides inclined at an angle to a plane transverse to the drive shaft greater than the angle between the plane and surfaces of the ballistic cam and of the striker member which slidably engage during the withdrawal of the striker member; said ballistic cam also having a radially displaceable stop member including a resiliently supported ball whereby the ballistic cam is held at an axial position of disengagement from the coupling member when the striker member is advanced beyond the normal striking position.
Claim 4
Dependent Claim
217 words
A hammer drill having a hollow spindle for receiving a drilling tool, a drive shaft arranged to rotate the spindle and exteNding parallel thereto, a striker member receivable in the spindle, and a ballistic cam on the drive shaft arranged to be rotated thereby to cause the striker member to be cyclically withdrawn against a spring and released to effect a striking action, the striker member being arranged to advance beyond the normal striking position on removal of the tool from a workpiece and thereby prevent rotation of the ballistic cam; said ballistic cam being rotatable and axially displaceable on the drive shaft and urged by a second spring towards coupling engagement with a coupling member mounted to rotate with the drive shaft; said coupling member having clutch dogs and said ballistic cam having sides inclined at an angle to a plane transverse to the drive shaft greater than the angle between the plane and surfaces of the ballistic cam and of the striker member which slidably engage during the withdrawal of the striker member; said ballistic cam also having a radially displaceable stop member including a resiliently supported ball whereby the ballistic cam is held at an axial position of disengagement from the coupling member when the striker member is advanced beyond the normal striking position.
Claim 5
Dependent Claim
253 words
A hammer drill having a hollow spindle for receiving a drilling tool, a drive shaft arranged to rotate the spindle and extending parrallel thereto, a striker member receivable in the spindle, and a ballistic cam on the drive shaft arranged to be rotated thereby to cause the striker member to be cyclically withdrawn against a spring and released to effect a striking action, the striker member being arranged to advance beyond the normal striking position on removal of the tool from a workpiece and thereby prevent rotation of the ballistic cam; said ballistic cam being rotatable and axially displaceable on the drive shaft and urged by a second spring towards coupling engagement with a coupling member mounted to rotate with the drive shaft; said coupling member having clutch dogs and said ballistic cam having sides inclined at an angle to a plane transverse to the drive shaft greater than the angle between the plane and surfaces of the ballistic cam and of the striker member which slidably engage during the withdrawal of the striker member; said ballistic cam also having a radially displaceable stop member including a resliently supported ball whereby the ballsitic cam is held at an axial position of disengagement from the coupling member when the striker member is advanced beyond the normal striking position; the inner end of said stop member engaging an annular groove in the drive shaft when the striker member engages the ball of the stop member with the striker member advanced beyond the normal striking position.
Claim 6
Dependent Claim
253 words
A hammer drill having a hollow spindle for receiving a drilling tool, a drive shaft arranged to rotate the spindle and extending parrallel thereto, a striker member receivable in the spindle, and a ballistic cam on the drive shaft arranged to be rotated thereby to cause the striker member to be cyclically withdrawn against a spring and released to effect a striking action, the striker member being arranged to advance beyond the normal striking position on removal of the tool from a workpiece and thereby prevent rotation of the ballistic cam; said ballistic cam being rotatable and axially displaceable on the drive shaft and urged by a second spring towards coupling engagement with a coupling member mounted to rotate with the drive shaft; said coupling member having clutch dogs and said ballistic cam having sides inclined at an angle to a plane transverse to the drive shaft greater than the angle between the plane and surfaces of the ballistic cam and of the striker member which slidably engage during the withdrawal of the striker member; said ballistic cam also having a radially displaceable stop member including a resliently supported ball whereby the ballsitic cam is held at an axial position of disengagement from the coupling member when the striker member is advanced beyond the normal striking position; the inner end of said stop member engaging an annular groove in the drive shaft when the striker member engages the ball of the stop member with the striker member advanced beyond the normal striking position.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-14 | 1978-04-15 | 1978-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-14 | 1982-04-15 | 1982-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-14 | 1986-04-15 | 1986-10-15 | $7700.00 | Window Closed / Lapsed |