Powered circular saw retention apparatus for retractable saw blade guard

• US 5,699,705 A
• Filed: 12/04/1995
• Issued: 12/23/1997
• Est. Priority Date: 12/04/1995
• Status: Expired due to Fees

• Current Assignee: Donald Dale Sibbet, Paul Mark Petersen
• Original Assignee: Donald Dale Sibbet, Paul Mark Petersen
• Inventors: Sibbet, Donald Dale
• Primary Examiner(s): Peterson, Kenneth E.
• Assistant Examiner(s): PRYOR, SEAN AUGUSTUS
• Application Number:
  US08/548,942
• Time in Patent Office: 750 Days
• Field of Search: 83/478, 83/13, 83/520, 83/397, 30/390, 30/391, 30/373, 30/286, 451/451, 451/454, 451/457
• US Class Current: 83/13
• CPC Class Codes: B23Q 11/06 Safety devices for circular cutters
• CPC Class Codes: B23Q 11/08 Protective coverings for parts of machine tools; Splash guards
• CPC Class Codes: B27G 19/04 for manually-operated power-driven circular saws
• CPC Class Codes: F16P 3/005 having a movable screen or a sensor influencing the switching system
• CPC Class Codes: Y10T 83/04 Processes
• CPC Class Codes: Y10T 83/606 Interrelated tool actuating means and guard means
• CPC Class Codes: Y10T 83/7734 With guard for tool
• CPC Class Codes: Y10T 83/828 With illuminating or viewing means for work

Abstract

A retention apparatus for an electrically powered hand-held circular saw having a retractable lower saw blade guard, that holds the lower saw blade guard in the retracted position as long as the power on/off switch is activated. This lower saw blade guard holder enables the saw operator to readily manipulate the saw with one hand while using the other hand to improve the safety environment of the cutting action, such as holding the material to be cut, or keeping the power cord out of the path of the saw during the cutting activity. In one embodiment, the lower saw blade guard holder comprises an electromagnet, wired to the power on/off switch, which holds a section of ferromagnetic material on the lower saw blade guard. Another embodiment of this invention has the lower saw blade guard holder mechanically latched by a latch that is mechanically coupled to the power on/off switch. In one embodiment, the lower saw blade guard holder also contains a lamp for lighting up the material being cut.

Claims

1. A retention apparatus for an electrically powered hand-held circular saw, the circular saw having a retractable lower saw blade guard, a saw blade, a saw-blade motor for rotating the saw blade, and a power on/off switch that Supplies electrical power to the saw-blade motor when activated, the retention apparatus comprising:

a lower saw blade guard (LSBG) holder coupled to the power on/off switch wherein the LSBG holder engages the lower saw blade guard only when the lower saw blade guard is in a substantially retracted position and maintains the lower saw blade guard in the retracted position when power is applied to the motor, and releases the lower saw blade guard to allow the lower saw blade guard to return to a default position of covering the saw blade when power is not applied to the motor.

2. The retention apparatus for an electrically powered hand-held circular saw according to claim 1, wherein the lower saw blade guard holder comprises an electromagnet which is activated when the power on/off switch is activated and deactivated when the power on/off switch is deactivated.

3. The retention apparatus for an electrically powered hand-held circular saw according to claim 2, wherein the retractable lower saw blade guard comprises a ferromagnetic section which comes substantially in contact with the electromagnet when the lower saw blade guard is substantially retracted.

4. The retention apparatus for an electrically powered hand-held circular saw according to claim 2, wherein the electromagnet comprises a single winding about a single core.

5. The retention apparatus for an electrically powered hand-held circular saw according to claim 2, wherein the lower saw blade guard holder further comprises a lamp that directs light on a material being cut by the circular saw including substantial illumination on material on both sides of an expected saw kerf.

6. The retention apparatus for an electrically powered hand-held circular saw according to claim 1, wherein the lower saw blade guard holder comprises a mechanical latch mechanically coupled to the power on/off switch that retains the lower saw blade guard in the retracted position as long as the power on/off switch is activated, and releases the lower saw blade guard when the power on/off switch is deactivated.

7. The retention apparatus according to claim 1, wherein the lower saw blade guard holder comprises of an electro-mechanical mechanism which is activated when the power on/off switch is activated and deactivated when the power on/off switch is deactivated.

8. The retention apparatus according to claim 1, wherein the lower saw blade guard holder comprises of a mechanical mechanism which is activated when the power on/off switch is activated and deactivated when the power on/off switch is deactivated.

9. An electrically powered hand-held circular saw comprising:

a retractable lower saw blade guard;

a saw blade;

a saw-blade motor for rotating the saw blade;

a power on/off switch that supplies electrical power to the saw-blade motor when activated; and

a retention apparatus, the retention apparatus comprising;

a lower saw blade guard (LSBG) holder coupled to the power on/off switch wherein the LSBG holder engages the lower saw blade guard only when the lower saw blade guard is in a substantially retracted position and maintains the lower saw blade guard in the retracted position when power is applied to the motor, and releases the lower saw blade guard to allow the lower saw blade guard to return to a default position of covering the saw blade when power is not applied to the motor.

10. The electrically powered hand-held circular saw according to claim 9, wherein the lower saw blade guard holder comprises an electromagnet which is activated when the power on/off switch is activated and deactivated when the power on/off switch is deactivated. guard in the retracted position when power is applied to the motor, and releases the lower saw blade guard to allow the lower saw blade guard to return to a default position of covering the saw blade when power is not applied to the motor.

11. The electrically powered hand-held circular saw according to claim 10, wherein the retractable lower saw blade guard comprises a ferromagnetic section which comes substantially in contact with the electromagnet when the lower saw blade guard is substantially retracted.

12. The electrically powered hand-held circular saw according to claim 10, further comprising a lamp that directs light on a material being cut by the circular saw including substantial illumination on material on both sides of an expected saw kerf.

13. The electrically powered hand-held circular saw according to claim 9, wherein the lower saw blade guard holder comprises a mechanical latch mechanically coupled to the power on/off switch that retains the lower saw blade guard in the retracted position as long as the power on/off switch is activated, and releases the lower saw blade guard when the power on/off switch is deactivated.

14. The electrically powered hand-held circular saw according to claim 9, wherein the lower saw blade guard holder comprises of an electro-mechanical mechanism which is activated when the power on/off switch is activated and deactivated when the power on/off switch is deactivated.

15. The electrically powered hand-held circular saw according to claim 9, wherein the lower saw blade guard holder comprises of a mechanical mechanism which is activated when the power on/off switch is activated and deactivated when the power on/off switch is deactivated.

16. A method for holding a retractable lower saw blade guard of an electrically powered hand-held circular saw, the circular saw having a motor and a power on/off switch, the lower saw blade guard having a lever for manually urging the lower saw blade guard to a substantially retracted position the method comprising the steps of:

engaging the lower saw blade guard only when the lower saw blade guard is in a substantially retracted position and holding the lower saw blade guard in the substantially retracted position with a retention mechanism for as long as the power on/off switch is activated to apply power to the motor; and

automatically releasing the lower saw blade guard when power is not applied to the motor.

17. The method according to claim 16, wherein the step of holding comprises the step of electro-magnetically holding the lower saw blade guard, and the step of releasing comprises the step of electro-magnetically releasing the lower saw blade guard.

18. The method according to claim 17, wherein the step electro-magnetically holding the lower saw blade guard comprises holding a ferromagnetic section only when the lower saw blade guard is substantially retracted.

19. The method according to claim 17, further comprising the step of lighting a material being cut by the circular saw when the power on/off switch is activated.

20. The method according to claim 16, wherein the step of holding comprises the step of mechanically holding the lower saw blade guard, and the step of releasing comprises the step of mechanically releasing the lower saw blade guard when the power on/off switch is deactivated.