Blade drop for power device and method of manufacturing thereof

• US 9,511,429 B2
• Filed: 03/11/2014
• Issued: 12/06/2016
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH, Robert Bosch Tool Corporation (Robert Bosch GmbH)
• Original Assignee: Robert Bosch GmbH, Robert Bosch Technology Corporation
• Inventors: Doumani, Robert, Laliberte, Eric, Szweda, Timothy, Talesky, Mark
• Primary Examiner(s): Alie, Ghassem
• Application Number:
  US14/203,928
• Publication Number:
  US 20140260861A1
• Time in Patent Office: 1,001 Days
• Field of Search: 833/99, 834/772, 835/64, 835/081, 83/58, 83/621, 834/771, 834/78, 835/45, 835/221.8, 834/712, 831/021, 835/81, 836/63, 144/384, 144/391, 144/427, 144/154.5, 144/356, 324/688, 324/661
• US Class Current: 1/1
• CPC Class Codes: B23D 45/065 with the saw blade carried by a pivoted lever
• CPC Class Codes: B23D 59/001 Measuring or control devices, e.g. for automatic control of work feed pressure on band saw blade measuring in general G01; controlling in general G05
• CPC Class Codes: B27G 19/02 for circular saws
• CPC Class Codes: Y10T 83/626 Operation of member controlled by means responsive to position of element remote from member [e.g., interlock]

Abstract

A table saw in one embodiment a swing arm movable along a swing arm path between a first swing arm position adjacent a latch hold mechanism and a second swing arm position spaced apart from the latch hold mechanism, a blade supported by the swing arm, a charge coupling plate mounted in close proximity to the blade so as to form a capacitor, an actuating device configured to transfer a force to the swing arm when the swing arm is maintained at the first swing arm position resulting in a bias on the latch hold mechanism, and a control system configured to control the actuating device to transfer the force to the swing arm in response to a sensed change in capacitance of the capacitor.

Claims

1. A table saw, comprising:

a swing arm movable along a swing arm path between a first swing arm position adjacent a latch hold mechanism and a second swing arm position spaced apart from the latch hold mechanism;

a blade supported by the swing arm;

a charge coupling plate holder supported by the swing arm;

a charge coupling plate mounted to the charge coupling plate holder with a plurality of screws and having a plurality of springs located between the charge coupling plate and the charge coupling plate holder, the charge coupling plate electrically isolated from the swing arm by the charge coupling plate holder and mounted in close proximity to the blade so as to form a capacitor;

an actuating device configured to transfer a force to the swing arm when the swing arm is maintained at the first swing arm position resulting in a bias on the latch hold mechanism; and

a control system configured to control the actuating device to transfer the force to the swing arm in response to a sensed change in capacitance of the capacitor.

2. The table saw of claim 1, further comprising:

at least one shot box operably connected to the swing arm; and

at least one counterweight located within the at least one shot box and configured to move within the at least one shot box.

3. The table saw of claim 2, wherein the at least one shot box is integrally formed with the swing arm.

4. The table saw of claim 2, wherein the at least one shot box is arcuately shaped.

5. The power tool of claim 4, further comprising:

at least one shot box operably connected to the swing arm; and

at least one counterweight located within the at least one shot box and configured to move within the at least one shot box.

6. The power tool of claim 5, wherein the shaping device is a saw blade.

7. The table saw of claim 1, further comprising:

a work support surface;

a carriage movable with respect to the work support surface and including a swing arm support;

a hinge shaft supported by the carriage;

a first bearing supported by the hinge shaft and rotatably supporting the swing arm;

a second bearing supported by the hinge shaft and rotatably supporting the swing arm; and

a shaft bolt configured to engage the hinge shaft such that the first bearing is forced toward the second bearing.

8. The table saw of claim 7, further comprising:

at least one shot box operably connected to the swing arm; and

at least one counterweight located within the at least one shot box and configured to move within the at least one shot box.

9. The table saw of claim 1, wherein each of the plurality of screws extends at least partially within a respective one of the plurality of springs.

10. The table saw of claim 1, wherein:

the charge coupling plate holder includes a plurality of spring wells; and

each of the plurality of springs is positioned at least partially within a respective on of the plurality of spring wells.

11. The table saw of claim 10, wherein:

each of the plurality of spring wells includes a respective threaded bottom portion; and

each of the plurality of screws is threaded into a respective one of the respective threaded bottom portions.

12. The table saw of claim 11, wherein each of the plurality of screws extends at least partially within a respective one of the plurality of springs.

13. A power tool, comprising:

a swing arm movable along a swing arm path between a first swing arm position adjacent a latch hold mechanism and a second swing arm position spaced apart from the latch hold mechanism;

a shaping device supported by the swing arm;

a charge coupling plate holder supported by the swing arm;

a charge coupling plate mounted to the charge coupling plate holder with a plurality of screws and having a plurality of springs located between the charge coupling plate and the charge coupling plate holder, the charge coupling plate electrically isolated from the swing arm by the charge coupling plate holder and mounted in close proximity to the shaping tool so as to form a capacitor;

an actuating device configured to transfer a force to the swing arm when the swing arm is maintained at the first swing arm position resulting in a bias on the latch hold mechanism; and

a control system configured to control the actuating device to transfer the force to the swing arm in response to a sensed change in capacitance of the capacitor.

14. The power tool of claim 13, further comprising:

at least one shot box operably connected to the swing arm; and

at least one counterweight located within the at least one shot box and configured to move within the at least one shot box.

15. The power tool of claim 14, wherein the at least one shot box is integrally formed with the swing arm.

16. The power tool of claim 14, wherein the at least one shot box is arcuately shaped.

17. The power tool of claim 13, further comprising:

a work support surface;

a carriage movable with respect to the work support surface and including a swing arm support;

a hinge shaft supported by the carriage;

a first bearing supported by the hinge shaft and rotatably supporting the swing arm;

a second bearing supported by the hinge shaft and rotatably supporting the swing arm; and

a shaft bolt configured to engage the hinge shaft such that the first bearing is forced toward the second bearing.

18. The power tool of claim 13, wherein each of the plurality of screws extends at least partially within a respective one of the plurality of springs.

19. The power tool of claim 13, wherein:

the charge coupling plate holder includes a plurality of spring wells; and

each of the plurality of springs is positioned at least partially within a respective on of the plurality of spring wells.

20. The power tool of claim 19, wherein:

each of the plurality of spring wells includes a respective threaded bottom portion; and

each of the plurality of screws is threaded into a respective one of the respective threaded bottom portions.