Apparatus and method for detecting dangerous conditions in power equipment

• US 20030131703A1
• Filed: 01/15/2003
• Published: 07/17/2003
• Est. Priority Date: 01/16/2002
• Status: Abandoned Application

• Current Assignee: SD3, LLC
• Original Assignee: SD3, LLC
• Inventors: Huebner, Randall J., Fanning, David A., Gass, Stephen F., Fulmer, J. David
• Application Number:
  US10/345,630
• Publication Number:
  US 20030131703A1
• Time in Patent Office: Days
• US Class Current: 83/62.1
• 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: B23Q 11/0082 by determining whether the operator is in a dangerous position B23Q17/2438 takes precedence
• CPC Class Codes: B23Q 11/0092 actuating braking or stopping means
• CPC Class Codes: B23Q 11/06 Safety devices for circular cutters
• CPC Class Codes: B23Q 17/2438 of an operator or a part thereof
• CPC Class Codes: B27B 13/14 Braking devices specially designed for band sawing machines, e.g. acting after damage of the band saw blade
• CPC Class Codes: B27B 5/38 Devices for braking the circular saw blade or the saw spindle; Devices for damping vibrations of the circular saw blade, e.g. silencing vibration-damping of sawing machines or devices working with circular saw blades B23D47/005
• CPC Class Codes: F16P 3/12 with means, e.g. feelers, which in case of the presence of a body part of a person in or near the danger zone influence the control or operation of the machine F16P3/08 takes precedence
• CPC Class Codes: Y10S 83/01 Safety devices
• CPC Class Codes: Y10T 83/081 With randomly actuated stopping means
• CPC Class Codes: Y10T 83/089 Responsive to tool characteristic
• CPC Class Codes: Y10T 83/148 Including means to correct the sensed operation
• CPC Class Codes: Y10T 83/162 With control means responsive to replaceable or selectable information program
• CPC Class Codes: Y10T 83/175 With condition sensor
• CPC Class Codes: Y10T 83/768 Rotatable disc tool pair or tool and carrier
• CPC Class Codes: Y10T 83/7726 By movement of the tool
• CPC Class Codes: Y10T 83/773 Work-support includes passageway for tool [e.g., slotted table]
• CPC Class Codes: Y10T 83/7788 Tool carrier oscillated or rotated

Abstract

A machine such as a saw, jointer, planer, etc. is disclosed. The machine has cutting tool, a direct drive mechanism configured to move the cutting tool, a detection system adapted to detect the occurrence of an unsafe condition between a person and the cutting tool, and a reaction system adapted to mitigate the unsafe condition upon the detection of the unsafe condition by the detection system. An electrical signal is imparted on the cuffing tool, and the signal is used to determine the occurrence of the unsafe condition. The direct drive mechanism is electrically isolated so that the electric signal may be imparted on the cutting tool. The electric isolation may be achieved through configurations such as insulated bearings, a substantially non-conductive housing, and a substantially non-conductive coupling joining two shaft portions.

Claims

1. A saw comprising:

a circular blade adapted to spin;

a motor configured to spin the blade;

a detection system adapted to detect contact between the blade and a person, where the detection system is adapted to impart an electrical signal on the blade;

a reaction system adapted to stop the blade from spinning upon the detection of the contact by the detection system; and

a direct drive system interconnecting the a motor and the blade, where the direct drive system includes at least two shaft portions coupled by a substantially nonconductive coupling.

2. The saw of claim 1, where the non-conductive coupling is a gear, and where at least a portion of the gear is made of a substantially non-conductive material.

3. The saw of claim 2, where the portion of the gear made of a substantially non-conductive material is sandwiched between metal portions.

4. The saw of claim 2, where the gear includes metal teeth and a substantially non-conductive portion isolating the metal teeth.

5. The saw of claim 2, where the gear is made at least substantially from a substantially non-conductive material.

6. The saw of claim 1, where the non-conductive coupling includes a gear, a substantially non-conductive spacer that mates with the gear, and a drive hub mounted to the spacer.

7. The saw of claim 6, where the gear and drive hubs are mounted on shaft portions, where the shaft portions are supported by bearings, and where the bearings are supported in insulating bushings.

8. The saw of claim 6, where the gear and drive hubs are mounted on shaft portions, where the shaft portions are supported by bearings, and where insulating bushings are positioned between the shaft portions and the bearings.

9. The saw of claim 1, where the non-conductive coupling includes a eccentric portion, a substantially non-conductive sleeve configured to fit over and insulate the eccentric portion, and a gear configured with an opening to receive the eccentric portion and sleeve.

10. The saw of claim 1, where the substantially non-conductive coupling is a planetary gear assembly.

11. The saw of claim 10, where the planetary gear assembly includes a substantially non-conductive housing.

12. The saw of claim 10, where the planetary gear assembly includes planetary gears made from substantially non-conductive material.

13. The saw of claim 1, where the motor is a switched reluctance motor.

14. The saw of claim 1, further comprising a housing supporting the motor.

15. A saw comprising:

a circular cutting tool, where the cutting tool is adapted to spin;

a direct drive mechanism configured to spin the cutting tool;

a detection system adapted to detect the occurrence of an unsafe condition between a person and the cutting tool, where the detection system is adapted to impart an electrical signal on the cutting tool; and

a reaction system adapted to mitigate the unsafe condition upon the detection of the unsafe condition by the detection system;

where the direct drive mechanism is electrically isolated so that the electric signal may be imparted on the cutting tool.

16. The saw of claim 15, where the direct drive mechanism is in a substantially non-conductive container, and the container is mounted in the operative structure.

17. The saw of claim 15, where the direct drive mechanism includes a switched reluctance motor and an electrically isolated drive shaft.

18. The saw of claim 15, where the direct drive mechanism includes a electrically isolated drive shaft.

19. The saw of claim 15, further comprising a housing supporting the direct drive mechanism.

20. A saw comprising:

a circular cutting tool adapted to spin;

at least one motor configured to move the cutting tool;

a detection system adapted to detect the occurrence of an unsafe condition between a person and the cutting tool, where the detection system is adapted to impart an electrical signal on the cutting tool;

a reaction system adapted to mitigate the unsafe condition upon the detection of the unsafe condition by the detection system; and

means for electrically isolating the cutting tool so that the electric signal may be imparted on the cutting tool.