Patent GB-1486757-A (GB)
Title: Rotary-to-linear motion conversion device
IPC: B41J7/52
Filed: 1976-06-15
Abstract: 1486757 Cams; linkwork INTERNATIONAL BUSINESS MACHINES CORP 15 June 1976 [26 June 1975] 24800/76 Heading F2K [Also in Division B6] Rotation of a shaft 10 is converted into linear motion, i.e. reciprocation of a non- rotatable follower block 18 thereon by a ballended cam follower plungers 26, 28 slidably mounted in a bore in the block 18 (or shaft 10) and urged by a leaf spring 24 into engagment with a V-section endless cam groove 12 in the shaft 10 (or block 18) the arrangement being such that the reciprocating movement of the block 18 in one direction is variably controlled by an adjustable width fixed stop 32, 34 against which a stop surface 22 on the block 18 engages to limit the reciprocating movement of the block 18 in the said one direction, the cam groove engaging followers ball 28 being forced up and out of the inclined walls of the V- section cam groove 12 to ride on the surface of the shaft 10 until, on continued rotation thereof, the ball 28 is re-aligned with and is spring- urged back into the cam groove 12 for the return reciprocating, i.e. linear movement in the opposite direction. The adjustable fixed stop 32, 34 basically comprises a fixed block 32 aligned with the surface 22 of the reciprocating sliding block 18 and between which one or more fingerlike spaced blocks 34 of variable, i.e. incremental thicknesses, arranged on pivotal thin flexible arms 36, may be pivotally interposed to adjustably vary the stop engaging face to limit the reciprocating travel of the sliding block 18 irrespective of the total effective axial, e.g. linear pitch of the endless cam groove 12. The finger-like spacer blocks 34 on the thin flexible arms 36 are each arranged on a bell-crank lever the longer, i.e. upper arms 50 of which seat against blade spring-like comb fingers 48 and the shorter arms of which are biased by springs 46 and have a lost-motion-slot engaged by links 38 which, to adjust the width of the stop and hence the reciprocating stroke of the block 18, are selectively pulled against the load of the respective return spring 46 to withdraw the respective incremental spacer 34 and lift the upper arm 50 above the appropriate prong of the comb fingers 48, which prong automatically springs beneath the end of the arm 50 to retain the spacer 34 in its withdrawn position. At the end of the rotary cycle a further cam 51 on the shaft 10 acting through a roller follower arm 49, turnable rod 53 and plate 52 therein releases the comb finger, i.e. prong 48 whereby the spring 46 returns the withdrawn incremental spacer 34 to its original position in the pack, the flexibility of the spacer arm 36 being such that as, one or more of the spacers are selectively withdrawn, the remaining spacers are deflected by the sliding block 18 until they abut against the fixed block 32. As shown, two such cam devices on a common shaft 10 are used in a typewriter for controlling the rotation and tilt of a single element golf ball type head 60, the two sliding blocks 18 each engaging a respective groove 12 in a common shaft 10 and each having an adjustable stop 32, 34 as above to selectively control the linear sliding movement of the blocks 18, the blocks 18 each being pivotally connected intermediate the ends of respective lever arms 30 each of which are fulcrumed at one end to a fixed pivot 31, the other ends of which levers 30 then effectively respectively control the rotation and tilt of the golf ball head 60 via links 54 and 62 respectively in known manner.