US 5,396,706 AGranted

Guard for portable circular saws

OwnerAleksander Fajnsztajninventor

Life of this patent

Estimating the term…

Loading patent…

Abstract

A portable, circular saw is disclosed. It includes a saw blade selectively rotatable about an axis of rotation to a define a working plane normal to such axis of rotation. The saw also includes an arcuate outer guard fixedly mounted about one side of the blade, and an inner guard having a central opening concentric of the axis of rotation. The purpose of the central opening is to permit the inner guard to be rotatably mounted about an opposite side of the blade. Also attached to the inner guard is a bulbous member that includes a leading edge that is adjacent to the cutting path of blade vis-a-vis a wooden member. Such wooden member generates a force on the inner guard as the former makes contact therewith and wherein the inner guard undergoes rotation about the axis of rotation. The bulbous member aids in the occurrence of such rotation by the fact that it substantially increases the engaging extent of the inner guard by a factor of at least 2 whereby jamming of rotation of the inner guard is prevented irrespective of position of the wooden member with respect to the inner guard.

Claims18

Dependent claims

A portable, circular saw including a saw blade selectively rotatable about an axis of rotation to a define a working plane normal to said axis of rotation, an arcuate outer upper guard fixedly mounted about a first sector of said blade of a selected arcuate angle A1 relative to said axis of rotation, an inner lower guard having a central opening concentric of said axis of rotation of said blade, said inner lower guard being rotatably mounted about a second sector of said blade on a side opposite to said first sector of angular dimension A2 wherein said blade is clear of said inner and outer guards over a cutting sector of angular dimension A3, said cutting sector being capable of expansion as a function of force generated by contact between a wooden member and said inner lower guard wherein said inner lower guard undergoes rotation about said axis of rotation, the amount of said displacement being a function of force applied to said inner lower guard, said inner lower guard also comprising two upright section members each having a leading edge and a trailing edge in a relaxed state of said saw, and a transverse section surrounding at least a portion of blade teeth of said saw wherein one of said upright sections is rotatable attached to said saw and the other section depends from said one section through said transverse section.

a bulbous member to prevent the work item being cut from jamming against said trailing edge of said other of said upright sections of said lower guard of said circular saw and preventing rotational motion of said lower guard;
said bulbous member comprising a disc fixedly attached to said other of said upright sections of said lower guard, said disc having a diameter that is at least twice the total upright extent of said other section of said lower guard so as to substantially increase vertical extent of the leading edge of said other section of said lower guard in said relaxed state of said saw so as aid the circular movement of said lower guard and prevent jamming thereof.

In a portable, circular saw including a saw blade selectively rotatable about an axis of rotation to a define a working plane normal to said axis of rotation, an arcuate outer upper guard fixedly mounted about said blade on one side of said blade, an inner lower guard having a central opening concentric of said axis of rotation of said blade, rotatably mounted about an opposite side of said blade, said inner lower guard also comprising two upright section members each having a leading edge and a trailing edge in a relaxed state of said saw, and a transverse section surrounding at least a portion of blade teeth of said saw wherein one of said upright sections is rotatable attached to said saw and the other section depends from said one section through said transverse section, the combination comprising

a wooden member to be cut by said blade, said wooden member generating a force on said inner lower guard as said wooden member makes contact therewith whereby said inner lower guard undergoes rotation about said axis of rotation, the amount of rotation being a function of force applied to said inner lower guard,
a bulbous member attached to said inner lower guard to define a leading edge that substantially increases the engaging extent of said inner guard to cause rotation, and to prevent said wooden member being cut from jamming against said trailing edge of said other of said upright sections of said lower guard of said circular saw and preventing rotatinal motion of said lower guard;
said bulbous member comprising a disc fixedly attached to said other of said upright sections of said lower guard, said disc having a diameter that is at least twice the total upright extent of said other section of said lower guard so as to substantially increase vertical extent of the leading edge of said other section of said lower guard in said relaxed state of said saw so as aid the circular movement of said lower guard whereby jamming of said rotation of inner lower guard is prevented irrespective of position of said wooden member with respect to said inner lower guard.

In a portable, circular saw including a saw blade selectively rotatable about an axis of rotation to a define a working plane normal to said axis of rotation, an arcuate outer upper guard fixedly mounted about said blade on one side of said blade, an inner lower guard having a central opening concentric of said axis of rotation of said blade, rotatably mounted about an opposite side of said blade, said inner lower guard also comprising two upright section members each having a leading edge and a trailing edge in a relaxed state of said saw, and a transverse section surrounding at least a portion of blade teeth of said saw therein one of said upright sections is rotatable attached to said saw and the other section depends from said one section through said transverse section, the improvement comprising

a bulbous member attached to said inner lower guard to define a leading edge that substantially increases the engaging extent of said inner lower guard to cause rotation, and to prevent a wooden member being cut form jamming against said trailing edge of said other of said upright sections of said lower guard of said circular saw and preventing rotational motion of said lower guard;
said bulbous member comprising a disc fixedly attached to said other of said upright sections of said lower guard, said disc having a diameter that is at least twice the total upright extent of said other section of said lower guard so as to substantially increase vertical extent of the leading edge of said other section of said lower guard in said relaxed state of said saw so as aid the circular movement of said lower guard whereby jamming of said rotation of inner lower guard is prevented irrespective of position of said wooden member to be cut relative to said inner lower guard.

Dependencies are inferred from the claim text.