Band saw with improved safety system

• US 9,927,796 B2
• Filed: 05/15/2002
• Issued: 03/27/2018
• Est. Priority Date: 05/17/2001
• Status: Active Grant

• Current Assignee: Sawstop Holding LLC
• Original Assignee: Sawstop Holding LLC
• Inventors: Gass, Stephen F.
• Primary Examiner(s): Peterson, Kenneth E
• Application Number:
  US10/146,527
• Publication Number:
  US 20020170400A1
• Time in Patent Office: 5,795 Days
• Field of Search: 324663, 324658, 327517, 83DIG 1, 83 58, 83 62, 83 621, 83788, 83820, 192129 R
• CPC Class Codes: B23D 55/00 Sawing machines or sawing devices working with strap saw blades, characterised only by constructional features of particular parts constructional features of these parts per se B23Q
• 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: 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 13/16 Accessories, e.g. for cooling the saw blade
• CPC Class Codes: B27G 19/00 Safety guards or devices specially adapted for wood saws; Auxiliary devices facilitating proper operation of wood saws
• CPC Class Codes: B27G 19/02 for circular saws
• CPC Class Codes: B27G 19/06 for band or strap saws
• CPC Class Codes: B27G 21/00 Safety guards or devices specially designed for other wood-working machines auxiliary devices facilitating proper operation of said wood-working machines
• 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: G05B 19/4061 Avoiding collision or forbidden zones
• CPC Class Codes: G05B 2219/45044 Cutting
• CPC Class Codes: G05B 2219/49152 Feedhold, stop motion if machine door is open, if operator in forbidden zone
• CPC Class Codes: G05B 2219/49159 Avoid pinching of persons between moving and fixed part
• 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 83/707 By endless band or chain knife
• CPC Class Codes: Y10T 83/7083 With cutter other than endlessly orbiting type

Abstract

A band saw including a frame, at least two, spaced apart, rotatable wheels supported by the frame, a blade looped around the wheels, where rotation of at least one wheel causes the blade to move around the wheels, a detection system adapted to detect a dangerous condition between a person and the blade, and a reaction system configured to engage and stop the blade within 10 milliseconds after detection of the dangerous condition is disclosed. The reaction system may be configured to cut and grip the blade.

Claims

1. A band saw comprising:

a frame;

at least two, spaced apart, rotatable wheels supported by the frame;

a blade looped around the wheels, where rotation of at least one wheel causes the blade to move around the wheels;

an electronic circuit adapted to detect contact between a person and the blade, where the electronic circuit uses capacitance to detect the contact, and where the electronic circuit generates a signal upon detection of the contact; and

a reaction system connected to the electronic circuit to receive the signal, where the reaction system is triggerable by the signal to engage and stop the blade within 10 milliseconds after being triggered, and where the reaction system includes a component moveable from a first position away from the blade to a second position in contact with the blade.

2. The band saw of claim 1, where the electronic circuit imparts an electric charge on the blade through a capacitive coupling.

3. The band saw of claim 2, where the wheels are electrically isolated from the frame.

4. The band saw of claim 2, where the blade is electrically isolated from the frame.

5. The band saw of claim 4, where the capacitive coupling includes a conductive plate positioned adjacent the blade.

6. The band saw of claim 2, further comprising a housing a enclosing the wheels, and where the housing is constructed to minimize any capacitive coupling between the housing and the wheels and/or blade.

7. The band saw of claim 2, further comprising a housing enclosing the wheels, where the housing is made at least partially of a non-conductive material.

8. The band saw of claim 1, where the reaction system also includes an electrically triggerable actuator, where the signal triggers the actuator, and where the actuator, when triggered, causes the component to move from the first position to the second position.