Sprinkler with radially limited nutating spool assembly

A fluid distributing sprinkler head, comprising,

• a fluid delivery tube in fluid connection with a nozzle;
• a sprinkler body comprising an upper sprinkler body and a lower sprinkler body, said upper sprinkler body partially enclosing said fluid delivery tube and nozzle;
• a spool assembly positioned within said lower sprinkler body, said spool assembly comprising,
• a spool body, said spool body comprising a spool body upper end and a spool body lower end;
• a distribution disc connected to said spool body upper end, wherein said nozzle is configured to direct fluid via a fluid path onto said distribution disc and onto said distribution disc, said distribution disc having a generally peaked surface, said generally peaked surface incised by spirally radiating grooves, said spirally radiating grooves configured to cause said spool assembly to nutate within said lower sprinkler body when impinged upon by fluid directed by said nozzle;
• wherein one of said spool assembly and an inner surface of said lower sprinkler body comprises an upper friction band and a lower friction band each circumvolving said spool assembly, wherein said upper friction band comprises an upper friction band outer diameter and said lower friction band comprises a lower friction band outer diameter;
• wherein the other of said inner surface of said lower sprinkler body and said spool assembly comprising an upper race and a lower race so as to radially limit nutation of said spool assembly within said lower sprinkler body, wherein at least one of said upper race and said lower race comprises a starter ramp, wherein said starter ramp is configured such that one of said upper friction band or said lower friction band rests on a lower end of said starter ramp when said sprinkler head is not running, wherein said sprinkler head is configured such that upon start up of fluid spraying on said distribution disc generating centrifugal force on said spool assembly and driving the spool assembly upward such that said upper friction band is in rolling engagement with said upper race and said lower friction band is in rolling engagement with said lower race;
• wherein said upper friction band and said lower friction band are spaced apart such that said upper friction band is configured for radially rolling engagement on an inner diameter of said upper race when said spool assembly is nutating within said lower sprinkler body and said lower friction band is configured for radially rolling engagement on said lower race when said spool assembly is nutating within said lower sprinkler body;
• and
• wherein said spool assembly is configured to rest in a tilted position within said sprinkler body such that said starter ramp of at least one of said lower race and said upper race is in resting engagement with one of said upper friction band and said lower friction band when said sprinkler head is not running.