Saw-blade driving device for a scroll saw

A scroll saw comprising:

• an elongated machine base;
• a table mounted pivotally on said machine base and adapted for placement of a workpiece to be sawn, said table being rotatable about a horizontal axis that extends in a longitudinal direction of said machine base;
• a C-shaped blade-holding arm fixed on said machine base, and having upper and lower arm portions that extend in the longitudinal direction of said machine base;
• a generally vertical saw blade;
• a saw-blade driving device including
• a motor disposed within said machine base and provided with a motor shaft that extends in the longitudinal direction of said machine base, and
• a linkage interconnecting said motor shaft and said saw blade so as to reciprocate said saw blade relative to said blade-holding arm, wherein said motor shaft is provided with an eccentric wheel member that is sleeved fixedly and eccentrically thereon, said linkage including;
• an upper swing arm having a middle portion that is disposed pivotally within said upper arm portion of said blade-holding arm so that said upper swing arm rotates about a horizontal axis that extends in a transverse direction of said machine base, a front end with an upper chuck that is connected thereto and that holds an upper end of said saw blade thereon, and a rear end,
• a lower swing arm having a middle portion that is disposed pivotally within said lower arm portion of said blade-holding arm so that said lower swing arm rotates about another horizontal axis that extends in the transverse direction of said machine base, a front end with a lower chuck that is connected thereto and that holds a lower end of said saw blade thereon, and a rear end,
• a generally vertical link having an upper end and a lower end,
• a horizontal upper pivot pin connecting said upper end of said link rotatably to said rear end of said upper swing arm,
• a horizontal lower pivot pin connecting said lower end of said link rotatably to said rear end of said lower swing arm,
• a driving rod having an upper end and a lower end,
• an upper spherical plain bearing interconnecting said rear end of said upper swing arm and said upper end of said driving rod, and
• a lower spherical plain bearing interconnecting said eccentric wheel member and said lower end of said driving rod so as to rotate said lower end of said driving rod about said motor shaft, thereby moving said upper end of said driving rod vertically relative to said machine base and consequently swinging said upper and lower swing arms reciprocally,
• wherein said saw blade is held between said front ends of said upper and lower swing arms and extends perpendicularly through said table.