Free-tracking phonograph pickup

Claim 1

IN A PHONOGRAPHY FOR PLAYING GROOVED DISC RECORDS ON A TURNTABLE, A PICKUP ASSEMBLY COMPRISING (A) A STYLUS FOR FOLLOWING THE DISC GROOVES, (B) A HEAD MOUNTING SAID STYLUS, (C) GUIDE MEANS SUPPORTED BY THE PHONOGRPAH, (D) SAID GUIDE MEANS INCLUDING LOW-FRICTION BEARING MEANS BETWEEN SAID HEAD AND SAID GUIDE MEANS PERMITTING LIMITED PIVOTAL VERTICAL MOTION OF THE HEAD ABOUT AN AXIS SUBSTANTIALLY AT THE SURFACE OF A RECORD DISC MOUNTED ON SAID TURNTABLE, (E) SAID GUIDE MEANS INCLUDING ALSO BEARING MEANS FOR GUIDING SAID HEAD WITH VERY LOW FRICTION IN A HORIZONTAL PATH SUCH THAT THE STYLUS MOVES ALONG A RADIAL PATH ON THE RECORD, (F) SAID BEARING MEANS COMPRISING HORIZONTAL LINEAR TRACT MEANS MOUNTED ON SAID PHONOGRAPH IN A PLANE WHICH IS VERY CLOSE TO THE PLANE OF THE PHONOGRAPH DISC RECORD, (G) TWO WHEELS FIXED TO SAID HEAD, ONE WHEEL ON EACH SIDE OF THE HEAD, AND WHEELS RIDING ON SAID TRACK MEANS FOR GUIDING THE STYLUS LATERALLY ALONG SAID RADIAL PATH, (H) SAID WHEELS BEING THIN DISCS WITH SHARP EDGES, SAID TRACK MEANS COMPRISING A GROOVED ELEMENT FOR RECEIVING SAID SHARP EDGES WITH SUBSTANTIALLY LINE CONTACT BETWEEN THE SHARP EDGES AND THE BOTTOM OF THE GROOVE, (I) SAID WHEEL AND THE ATTACHED HEAD BEING FREE TO MOVE PIVOTALLY AS A WHOLE FOR A LIMITED DISTANCE ABOUT THE LINE OF CONTACT BETWEEN THE WHEELS AND THE TRACK, TO PERMIT AT LEAST A SMALL AMOUNT OF VERTICAL MOVEMENT OF THE STYLUS WITH RESPECT TO THE SURFACE OF A RECORD.