Ergonomic grinder

• US 6,120,362 A
• Filed: 06/09/1997
• Issued: 09/19/2000
• Est. Priority Date: 06/09/1997
• Status: Expired due to Term

• Current Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: Porter-Cable Corporation (Stanley Black & Decker, Inc.)
• Inventors: Etter, Mark A., Smith, John C.
• Primary Examiner(s): Eley, Timothy V.
• Application Number:
  US08/871,447
• Time in Patent Office: 1,198 Days
• Field of Search: 451/344, 451/354, 451/358, 451/359, 15/79.1, 15/143.1, 16/110 R
• US Class Current: 451/354
• CPC Class Codes: B24B 23/028 Angle tools
• CPC Class Codes: B25F 5/02 Construction of casings, bodies or handles B25F5/006, B25F5/008 take precedence

Abstract

The present disclosure relates to an angle grinder including an elongated handle body having front and rear portions. The handle body has a greater nominal width proximate the front portion than proximate the rear portion. A recessed hand grip portion is defined by the handle body between the front and rear handle portions. The recessed hand grip portion transitions inward to a nominal girth that is smaller than the girth of both the front and rear portions. The recessed hand grip portion also includes a leading front wall that transitions from the smaller nominal girth of the grip portion toward the larger nominal girth of the front portion. The leading front wall is aligned at an angle that slopes in a forward direction as the leading front wall extends from the top side toward the bottom side of the handle body. The disclosure also relates to an angle grinder having a switch paddle pivotally connected to a handle. The switch paddle is sized and shaped to fit within a recess defied by the handle so as to form an integral part of the handle. The disclosure further relates to an angle grinder having a switch paddle equipped with an intermediate finger stop protrusion sized for supporting a user'"'"'s finger.

Claims

1. An angle grinder, comprising:

a tool housing having an elongated configuration, the housing substantially enclosing a motor having an armature shaft oriented generally parallel to a length of the elongated housing;

an output shaft adapted and configured to receive a grinding disc for rotation in a plane generally parallel to the armature shaft of the motor, the output shaft being located proximate a front end of and being oriented generally perpendicular to the length of the elongated housing, the output shaft extending in a downward direction away from the armature shaft such that the grinding disc is mounted below the tool housing;

a gear train for coupling the motor armature shaft to the output shaft; and

the tool housing comprising;

i. a handle body having an elongated shape having front and rear portions defined by the handle body, the handle body having a greater nominal girth proximate the front portion than proximate the rear portion, the handle body having a top side positioned opposite from a bottom side, and the bottom side facing in the downward direction;

ii. a recessed hand grip portion which is defined by the handle body, which is located between the front and rear handle portions, and which transitions inward to a nominal girth smaller than the girth of both the front and rear portions;

iii. the recessed hand grip portion including a leading front wall which transitions from the smaller nominal girth of the hand grip portion toward the larger nominal girth of the front portion, and a trailing back wall which transitions from the smaller nominal girth of the hand grip portion toward the larger nominal girth of the rear portion; and

iv. the leading front wall being aligned at an angle which slopes continuously in a forward direction as the leading front wall extends from the top side to the bottom side of the handle body, wherein a bottom portion of the leading front wall located at the bottom side of the handle body is positioned in front of a top portion of the leading front wall located at the top side of the handle body.

2. The angle grinder of claim 1 wherein the handle body is adapted and configured to provide multiple ambidextrous holding positions for a user'"'"'s hand.

3. The angle grinder of claim 2 wherein the handle and motor housing is adapted and configured to provide a home feel to no fewer than five multiple holding positions of the user'"'"'s hand.

4. The angle grinder of claim 1 wherein the leading front wall conforms to natural ergonomic grip angles of the user'"'"'s hand.

5. The angle grinder of claim 1 wherein the leading front wall is formed so that the user'"'"'s hand can push forward against it.

6. The angle grinder of claim 1 wherein the trailing back wall is defined by the handle body to have an angle which slopes in a downward direction toward the front handle portion.

7. The angle grinder of claim 6 wherein the trailing back wall conforms to natural ergonomic grip angles of the user'"'"'s hand.

8. The angle grinder of claim 6 wherein the leading front wall and the trailing back wall are substantially parallel to one another.

9. The angle grinder of claim 1 wherein the elongated shape is defined by the handle body to be a slightly-squared cylindrical shape in cross sectional configuration.

10. An angle grinder, comprising:

a tool housing having an elongated configuration, the housing substantially enclosing a motor having an armature shaft oriented generally parallel to the length of the elongated housing;

an output shaft adapted and configured to receive a grinding disc for rotation in a plane generally parallel to the armature shaft of the motor, the output shaft being located proximate a front end of and being oriented generally perpendicular to the length of the elongated housing, the output shaft extending in a downward direction away from the armature shaft such that the grinding disc is mounted below the tool housing;

a gear train for coupling the motor armature shaft to the output shaft;

the tool housing, including a handle body defining front and rear handle portions, the handle body also including an underside positioned opposite from a top side, the underside of the handle body facing in the downward direction;

a switch paddle located beneath the underside of the handle body and being coupled to the handle body by a pivotal connection located proximate the rear handle portion, the switch paddle being pivotally moveable about the pivotal connection in a direction toward the underside of the handle body for activation and use of the tool, the switch paddle including a recessable portion including a pair of upwardly projecting wings configured to straddle the handle body; and

the handle body defining, generally along the underside of the handle body between the front and rear handle portions, a recessed hand portion substantially conforming to the shape and thickness of the recessable portion of the switch paddle, the recessed hand portion also defining wing depressions positioned on opposite sides of the handle body for receiving the wings of the switch paddle, wherein the recessable portion of the switch paddle is adapted to fit within the recessed hand portion when the tool is activated and essentially become an integral part of the tool handle as perceived by the feel of a tool-user'"'"'s hand.

11. The angle grinder of claim 10 wherein the handle body and switch paddle are adapted and configured to provide multiple ambidextrous holding positions for a user'"'"'s hand.

12. The angle grinder of claim 10 wherein the switch paddle comprises a finger support portion long enough to support essentially all four fingers of a typical user'"'"'s hand.

13. The angle grinder of claim 10 wherein the switch paddle defines a finger stop section which is located on an underside of the switch paddle and which comprises a generally downwardly facing finger stop protrusion, the finger stop protrusion being oriented generally crosswise to the length of the switch paddle, wherein the user of the tool can selectively place fingers forward or rearward of the finger stop section as part of adjusting the user'"'"'s hand and finger positions during use of the tool.

14. The angle grinder of claim 13 wherein the protrusion is located approximately at a middle region along a length of the switch paddle.

15. The angle grinder of claim 13 wherein the protrusion comprises a releasable switch lock lever having a locked off position which prevents movement of the switch paddle toward the handle body, the switch lock lever further having an operational position permitting movement of the switch paddle toward the handle body and activation of the tool.

16. The angle grinder of claim 15 wherein the switch lock lever is pivotally coupled to the finger stop protrusion proximate a lower portion of the finger stop protrusion, the switch lock lever comprising an elongated member which in the locked off position protrudes from the pivotal coupling toward the tool handle body and from the pivotal coupling downward from the switch paddle, the switch lock lever being pivotally movable by the user'"'"'s hand to the operational position permitting movement of the switch paddle toward the handle body and activation of the tool.

17. The angle grinder of claim 10 wherein:

the handle body has a greater nominal girth proximate the front handle portion than proximate the rear handle portion; and

a recessed hand grip portion which is defined by the handle body, which is located between the front and rear handle portions, and which transitions inward to a nominal girth smaller than the girth of both the front and rear handle portions.

18. An angle grinder, comprising:

a tool housing having an elongated configuration, the housing substantially enclosing a motor having an armature shaft oriented generally parallel to the length of the elongated housing;

an output shaft adapted and configured to receive a grinding disc for rotation in a plane generally parallel to the armature shaft of the motor, the output shaft being located proximate a front end of and being oriented generally perpendicular to the length of the elongated housing, the output shaft extending in a downward direction away from the armature shaft such that the grinding disc is mounted below the tool housing;

a gear train for coupling the motor armature shaft to the output shaft; and

the tool housing including a handle body defining front and rear handle portions;

a switch paddle coupled to the handle body by a pivotal connection located proximate the rear handle portion, the switch paddle being pivotally moveable about the pivotal connection in a direction toward the handle body for activation and use of the tool, the switch paddle defining a finger stop section which is located on an underside of the switch paddle that faces in the downward direction and which comprises a generally downwardly extending protrusion, the protrusion being oriented generally crosswise to the length of the switch paddle, the protrusion being sized and shaped for fully supporting a finger of the user, wherein the user of the tool can selectively place fingers forward or rearward of the finger stop section as part of adjusting the user'"'"'s hand and finger positions during use of the tool.

19. The angle grinder of claim 18 wherein the switch paddle comprises a finger support portion long enough to support essentially all four fingers of a typical user'"'"'s hand.

20. The angle grinder of claim 19 wherein the protrusion is located approximately at a middle region along a length of the finger support portion.

21. The angle grinder of claim 18 wherein the protrusion comprises a releasable switch lock lever having a locked off position which prevents movement of the switch paddle toward the handle body, the switch lock lever further having an operational position permitting activation of the tool.

22. The angle grinder of claim 21 wherein the switch lock lever is pivotally coupled to the finger stop protrusion proximate a lower portion of the finger stop protrusion, the switch lock lever comprising an elongated member which in the locked off position protrudes from the pivotal coupling toward the tool handle body and from the pivotal coupling downward from the switch paddle, the switch lock lever being pivotally movable by the user'"'"'s hand to the operational position permitting movement of the switch paddle toward the handle body and activation of the tool.

23. An angle grinder, comprising:

a tool housing having an elongated configuration, the housing substantially enclosing a motor having an armature shaft oriented generally parallel to the length of the elongated housing, and the tool housing forming a handle having front and rear handle portions;

an output shaft adapted and configured to receive a grinding disc for rotation in a plane generally parallel to the armature shaft of the motor, the output shaft being located proximate a front end of and being oriented generally perpendicular to the length of the elongated housing, the output shaft extending in a downward direction away from the armature shaft such that the grinding disc is mounted below the tool housing;

a gear train for coupling the motor armature shaft to the output shaft; and

a switch paddle for activating and de-activating the motor, the switch paddle being located generally under the handle and coupled to the handle by a pivotal connection located proximate the rear handle portion, the switch paddle being pivotally moveable about the pivotal connection in a direction toward the handle for activation and use of the tool, and the switch paddle including a finger support portion long enough to support essentially all four fingers of a typical user'"'"'s hand, the switch paddle also including a finger stop protrusion that projects downwardly from the finger support portion, the finger stop protrusion being located at an intermediate position along a length of the finger support portion, and the finger stop protrusion being formed by first and second surfaces that concurrently extend in the downward direction and converge toward one another, and

a releasable switch lock lever pivotally mounted at the finger stop protrusion at a location between the first and second converging surfaces, the switch lock lever having a locked off position which prevents movement of the switch paddle toward the handle body, and the switch lock lever further having an operational position permitting activation of the tool.

24. The grinder of claim 23, wherein the handle forms a recessed hand grip portion located between the front and rear handle portions and having a reduced girth as compared to the front and rear handle portions.

25. The grinder of claim 24, wherein the switch paddle extends forward from the pivotal connection such that at least a portion of the switch paddle is located directly below the recessed hand grip portion.

26. The grinder of claim 25, wherein the handle defines a switch paddle recess adapted for receiving the switch paddle, the switch paddle recess being configured such that when the switch paddle is fully depressed, the switch paddle fits within the switch paddle recess and becomes essentially an integral part of the tool handle.

27. The grinder of claim 24, wherein the front handle portion has a larger girth than the rear handle portion.

28. The grinder of claim 24, wherein the recessed hand grip portion is at least partially defined by a leading wall and a trailing wall, the leading and trailing walls including side portions having directional components that extend in a longitudinal direction along the handle.

29. The grinder of claim 28, wherein the side portions of the leading and trailing walls are substantially parallel.