Blade guard arrangement in motor-driven chop saw

• US 4,774,866 A
• Filed: 01/07/1988
• Issued: 10/04/1988
• Est. Priority Date: 01/12/1987
• Status: Expired due to Fees

• Current Assignee: Ryobi Limited (Techtronic Industries Company Limited)
• Original Assignee: Ryobi Limited (Techtronic Industries Company Limited)
• Inventors: Miyamoto, Kouichi, Dehari, Tomoshige
• Primary Examiner(s): Yost, Frank T.
• Assistant Examiner(s): Smith, Scott A.
• Application Number:
  US07/141,412
• Time in Patent Office: 271 Days
• Field of Search: 83/478, 83/490, 83/397, 83/546, 83/481, 83/484, 83/581, 83/DIG. 1, 30/390, 30/391, 144/251 R, 144/251 A, 144/251 B, 144/216
• US Class Current: 83/478
• CPC Class Codes: B27G 19/02 for circular saws
• CPC Class Codes: Y10S 83/01 Safety devices
• 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 83/7788 Tool carrier oscillated or rotated

Abstract

A saw-blade guard arrangement in a motor driven chop saw which includes a new unit pivotally mounted for movement between an upper rest position and a lower operational position. The saw unit is pivotably connected to a hinging member through a pivot shaft, and the unit includes an upper safety guard, a motor casing integral with the upper guard, a saw blade fixed to a drive shaft connected to a motor shaft, and a lower guard rotatable to a first direction for covering a part of the saw blade when the saw unit is in the upper rest position and rotatable to a second direction when the unit is moved to the lower operational position. The blade guard arrangement comprises a first biasing means disposed between the upper safety guard and the hinging member, an operation arm having one end portion pivotally rotatable about the pivot shaft, a link member having one end pivotably connected to the other end of the operation arm and having the other end pivotally connected to the lower guard, a second biasing means disposed between the operation arm and the hinging member, and an adjusting means for controlling orientation of the operation arm.

Claims

1. A saw-blade guard arrangement in a motor driven chop saw, said chop saw including a saw table;

a hinging member extending from said saw table and having a pivot shaft; and

a saw unit pivotally movable with respect to said hinging member;

said saw unit including a sawblade, an upper safety guard for partially encasing said saw blade, said upper safety guard pivotably connected to said hinging member through said pivot shaft, a motor casing connected to said upper safety guard, a motor housed in said motor casing, a drive shaft connected to said motor and fixing said saw-blade for its rotation, and a lower guard rotatable to a first direction for covering an exposed segment of said saw blade when said saw unit is in the upper rest position and rotatable to a second direction for uncovering said segment when the saw-unit is moved to the lowered operational position, said saw-blade guard arrangement comprising;

a first biasing means disposed between said upper safety guard and said hinging member for urging said upper safety guard toward its upper rest position;

an operation arm having one end portion pivotally rotatable about said pivot shaft;

a link member having one end pivotally connected to other end of said operation arm, and having the other end pivotally connected to said lower guard, said lower guard being rotatably connected to a bearing portion of said drive shaft;

a second biasing means disposed between said operation arm and said hinging member for urging said operation arm to a direction for urging said lower guard to said first direction; and

,

an adjusting means for controlling orientation of said operation arm, said adjusting means being provided on said hinging member at a position adjacent an end face of said one end portion of said operation arm.

2. The saw-blade guard arrangement as defined in claim 1, wherein said first and second biasing means are disposed over said pivot shaft.

3. The saw-blade guard arrangement as defined in claim 1, wherein said adjusting means comprising a bolt, and a rib portion extending from said hinging member at a position adjacent said pivot shaft, said bolt threadingly engaged with said rib portion and being in abutment with said end face of said operation arm, axis of said bolt being spaced away from an axis of said pivot shaft, said end face being urged toward said bolt by said second biasing means.

4. The saw-blade guard arrangement as defined in claim 2, wherein said first biasing means has one end engaged with an inner face of a rear wall of said upper safety guard, and the other end engaged with a spring seat projecting from said hinging member.

5. The saw-blade guard arrangement as defined in claim 2, wherein said second biasing means has one end engaged with an inner face of a rear wall of said upper safety guard, and the other end engaged with a bottom wall of said operation arm.