Anti-kick forward device for power driven saws

• US 5,331,875 A
• Filed: 10/06/1992
• Issued: 07/26/1994
• Est. Priority Date: 06/28/1990
• Status: Expired due to Term

• Current Assignee: One World Technologies (Techtronic Industries Company Limited)
• Original Assignee: Ryobi America Corporation (Techtronic Industries Company Limited)
• Inventors: Mayfield, Alfred B.
• Primary Examiner(s): Seidel, Richard K.
• Assistant Examiner(s): Peterson, Kenneth E.
• Application Number:
  US07/957,251
• Time in Patent Office: 658 Days
• Field of Search: 83/471.2, 83/471.3, 83/483, 83/484, 83/485, 83/486.1, 83/DIG. 1, 83/76, 192/7, 192/41 R, 192/45, 188/82.84, 188/139
• US Class Current: 83/485
• CPC Class Codes: B23D 45/025 Radial sawing machines
• CPC Class Codes: B23D 47/08 of devices for bringing the circular saw blade to the workpiece or removing same therefrom
• CPC Class Codes: B23Q 5/58 Safety devices protecting the operator B23Q11/0089
• CPC Class Codes: Y10S 83/01 Safety devices
• CPC Class Codes: Y10T 83/7697 Tool angularly adjustable relative to work-support
• CPC Class Codes: Y10T 83/7763 Tool carrier reciprocable rectilinearly
• CPC Class Codes: Y10T 83/7772 Angular relative to previous path

Abstract

A saw includes a mounting arm or linear slide area, a carriage mounted on the arm for linear movement in first and second directions along the arm or slide area, a saw blade mounted on the carriage for rotational movement relative to the carriage about an axis of rotation extending in a direction transverse to the linear direction of travel of the carriage, and power means adapted to rotate the saw blade about the axis of rotation for carrying out a sawing operation. A kick-preventing apparatus, which may be produced as a retrofittable device, is provided for limiting the maximum speed at which the carriage may be moved in the first direction to a predetermined speed, the kick-preventing means permitting the carriage to be moved in the first direction at any speed equal to or less than the predetermined speed while preventing the carriage from kicking along the arm or slide in the first direction at a speed greater than the predetermined speed.

Claims

1. In a radial arm saw including a mounting arm, a carriage mounted on the arm for linear movement in first and second directions along the arm, the carriage being adapted to support a saw blade for rotational movement relative to the carriage about an axis of rotation extending in a direction transverse to the linear direction of travel of the carriage, and power means for rotating the saw blade about the axis of rotation for carrying out a sawing operation, the improvement comprising:

kick-preventing means for limiting the maximum speed at which the carriage may be moved in the first direction along the mounting arm to a predetermined speed, the kick preventing means permitting free unrestricted movement of the carriage in the first direction at any speed equal to or less than the predetermined speed while preventing movement of the carriage in the first direction at a speed greater than the predetermined speed;

wherein the kick-preventing means includes a drive means, an over-running clutch, and a carriage-movement control assembly mounted on the arm and connected to the carriage, the over-running clutch having an input shaft connected to the drive means and an output shaft connected to the carriage-movement control assembly and being operable to prevent rotational movement of the output shaft of the clutch in at least one direction at a speed greater than the speed of rotation of the input shaft of the clutch such that the carriage-movement control assembly limits the maximum travel speed of the carriage to the predetermined speed; and

wherein the drive means includes a motor.

2. The radial arm saw as recited in claim 1, wherein the kick-preventing means includes setting means for adjusting the predetermined speed at which the carriage may be moved in the first direction along the mounting arm.

3. The radial arm saw as recited in claim 1, wherein the kick-preventing means includes actuating means for enabling the kick-preventing means to permit movement of the carriage in the first direction along the arm at a speed slower than the predetermined speed if desired, and locking means for preventing movement of the carriage in the first direction when the actuating means is not operated.

4. The radial arm saw as recited in claim 1, wherein the kick-preventing means permits free unrestricted movement of the carriage in the second direction at any speed.

5. The radial arm saw as recited in claim 1, further comprising deactivation means for deactivating the kick-preventing means in order to permit unrestricted movement of the carriage in both the first and second directions.

6. The radial arm saw as recited in claim 5, wherein the deactivation means includes switch means for switching off the power means whenever the kick-preventing means is deactivated.

7. The radial arm saw as recited in claim 1, wherein the drive means includes the power means for rotating the saw blade.

8. The radial arm saw as recited in claim 7, wherein the power means includes an electric motor having a rotatable output shaft and the drive means includes a gear reduction assembly having an input and an output, means for transmitting rotational movement of the output shaft of the motor to the input of the gear reduction assembly, and means for transmitting rotational movement from the output of the gear reduction assembly to the input shaft of the overrunning clutch.

9. The radial arm saw as recited in claim 8, wherein the gear reduction assembly includes means for varying the gear reduction ratio of the gear reduction assembly.

10. A kick-preventing assembly for use with a saw including a mounting arm, a carriage mounted on the arm for linear movement in first and second directions along the arm, the carriage being adapted to support a saw blade for rotational movement relative to the carriage about an axis of rotation extending in a direction transverse to the linear direction of travel of the carriage, and power means adapted to rotate the saw blade about the axis of rotation for carrying out a sawing operation, the kick-preventing assembly comprising:

speed limiting means for limiting the maximum speed at which the carriage may be moved in the first direction along the mounting arm to a predetermined speed, the speed limiting means permitting free unrestricted movement of the carriage in the first direction at any speed equal to or less than the predetermined speed while preventing movement of the carriage in the first direction at a speed greater than the predetermined speed;

wherein the speed limiting means further comprises an over-running clutch which is driven by a motor.

11. The kick-preventing assembly as recited in claim 10, wherein the speed-limiting means includes actuating means for enabling the speed-limiting means to permit movement of the carriage in the first direction along the arm at a speed slower than the predetermined speed if desired, and locking means for preventing movement of the carriage in the first direction when the actuating means is not operated.

12. The kick-preventing assembly as recited in claim 10, wherein the speed-limiting means permits free unrestricted movement of the carriage in the second direction any speed.

13. The kick-preventing assembly as recited in claim 10 further comprising deactivation means for deactivating the speed-limiting means in order to permit unrestricted movement of the carriage in both the first and second directions.

14. The kick-preventing assembly as recited in claim 13, wherein the deactivation means includes switch means for switching off the power means whenever the speed-limiting means is deactivated.

15. The kick-preventing assembly as recited in claim 10, further comprising setting means for allowing adjustment of the predetermined speed at which the carriage may be moved in the first direction along the mounting arm.

16. The kick-preventing assembly as recited in claim 10 further comprising a flexible tensile member affixed to the carriage and cooperating with the speed limiting means to limit the speed of movement of the carriage.

17. The kick-preventing assembly as recited in claim 10, wherein the motor is a variable speed motor.