Bidirectional tape transport with reversible head mechanism driven by lapstan motor

Claim 2

In a heads reversing mechanism for a multitrack bidirectional tape transport having a capstan wherein said heads are rotated as an assembly for 180* about an axis normal to the plane of the tape and to a different subset of said tracks when the capstan changes direction, an apparatus sensitive to the direction of capstan motion for causing positive operation of the mechanism, comprising: first rotating means coupled to said capstan for continuous and reversible rotation therewith; second rotating means coupled to said heads for rotating same about said axis; and means operable by change of direction of said capstan to cause coupling of said first and second rotating means for a predetermined conjoint rotation of limited degree to cause the desired 180* rotation of said heads.

Claim 3

Apparatus as recited in claim 1, wherein: said first rotating means includes a crown gear driven by the capstan means and reversing when said capstan reverses; said second rotating means includes a rotating cam mounted in axial alignment with said crown gear and said coupling means includes a detent sliding in a radial slot of said cam for engagement and disengagement with the teeth of said crown gear, and a clutch plate mounted for rotation with said first rotating means through a predetermined limited sector of rotation, said clutch plate having cam surfaces formed thereon and means engaging said cam surfaces for causing said engagement and disengagement of said detent to couple and uncouple said capstan and said rotating cam.

Claim 4

Apparatus as recited in claim 2, wherein; said second rotating means includes a head mounting plate mounting said heads and a shaft therefor, mounted for rotation on an axis normal to the rotational axis of said crown gear and cam; and cam-follower means coupled to said shaft for causing retraction of said head mounting plate and heads away from said tape and parallel to said axis thereof and into engagement with said rotating crown gear for driven rotation about said plate axis for 180*, followed by return of said plate and heads parallel to said axis thereof and into engagement with said tape again; guide means being provided for holding said tape during the retraction rotation and return of said plate and heads.

Claim 5

Apparatus as recited in claim 3, wherein: latch means are provided for engaging said rotating cam means and said head mounting plate, said latch means being shiftable upon each change of direction of said cam to release said head mounting plate for said 180* rotation and for securely latching said plate in a fixed rotational position upon completion of said 180* rotation and until a subsequent change of direction of said cam.

Claim 6

Apparatus as recited in claim 4, wherein: head guide means are provided for receiving and engaging said head mounting plate upon said return thereof toward said tape and for gaugeably aligning said plate with said heads in precisely predetermined operating positions with respect to said tape.

Claim 7

Apparatus as recited in claim 5, wherein: said clutch plate has a radial extension with a chevron-shaped slot formed therein and defining said cam surfaces thereof: and said means engaging said cam surfaces includes a generally tangentially pivoting lever with a pin extending therefrom and through said chevron-shaped slot, so that said lever is caused to pivot radially outwardly and then inwardly again upon each change of direction of said crown gear; and said lever is arranged to engage said detent for permitting coupling of said rotating cam and crown gear as said lever pivots outwardly.

Claim 8

Apparatus as recited in claim 6, wherein: said detent is formed as a stepped plate snugly retained iN said groove and between said rotating cam and said crown gear; said detent having an extended portion lying entirely out of the plane of said crown gear and projecting radially outwardly to engage said lever in the radially inward position of said lever, with said stepped portion of said detent retracted radially inwardly from the toothed portion of said crown gear; said detent being spring-loaded for sliding movement radially outwardly to a position of engagement of said stepped portion thereof with said toothed portion of said crown gear when said lever pivots radially outwardly.

Claim 9

Apparatus as recited in claim 7, wherein: said rotating cam has a peripheral V-shaped notched portion; and there is also provided a springloaded V-shaped detent lever engaging said notched portion of said rotating cam when said detent engages said lever; the sides of said V-shaped notched portion and said V-shaped detent lever being angled so that said V-shaped detent lever is urged out of said notched portion when said rotating cam begins to rotate upon being keyed by said detent to said crown gear.

Claim 10

Apparatus as recited in claim 8, wherein: said rotating cam has a cam groove formed in one flat face thereof, said groove lying at a constant radius from the axis of said rotating cam for all but a limited sector thereof and being formed within said sector to an inwardly directed V-shaped pattern; said cam follower means includes a cam follower plate mounted for sliding motion normal to the path of said tape and parallel to the rotational axis of said head mounting plate and shaft; and a pin is mounted transfixing said cam follower plate parallel to the rotational axis of said rotating cam and engaging with one end said cam groove thereof, and with the other end a conforming circumferential groove in said head mounting plate shaft, for moving said head mounting plate away from and back again toward said tape as said rotating cam is rotated.

Claim 11

Apparatus as recited in claim 9, wherein: said latch means includes a latch plate mounted for limited sliding motion in a plane parallel to the path of said tape and springloaded to frictionally engage the periphery of said rotating cam so as to be shifted in opposite directions when said rotating cam changes rotational directions; said latch plate having a pair of bevel-tipped hook-shaped sear portions arranged for engaging a conforming pin extending from said head mounting plate in each of the two rotational positions thereof 180* apart, for latching said head mounting plate in said positions until the next subsequent reversal of said rotating cam.