Abstract 1,072,438. Adjustable seat backs. ANDERSON CO. Aug. 4, 1964 [July 25, 1963], No. 30976/64. Heading A4J. [Also in Division E2] A mechanical position-retaining device for chairs has a first member 110 for attachment to a chair base (189) Fig. 4 (not shown) and a second member 112 rectilinearly movable relative to the first member for attachment to a chair back (190) positionable with respect to the chair base. A nut 142 is fixedly carried by member 112 and has internal threading to co-operate with a threaded rod 138, the threading being relatively steep so that an axial force applied by the chair back rectilinearly between the members 110, 112 tends to rotate the rod 138. Such rotation is prevented by a brake consisting of a resilient coil 158, connected at one end 160 to a base part 116 of the member 110, surrounding and gripping a drum 144 connected to the threaded rod 138. The brake is releasable by engaging a squared end (164) Fig. 3 (not shown) of coil 158 by a shoulder (176) of a release member 166 to increase the inner diameter of the coil. A resilient friction washer 152 is disposed between the part 116 of the member 110 and the rotatable rod 138 to dampen rotation of the rod and hence the relative rectilinear movement of the members 110, 112.
A MECHANICAL POSITION-RETAINING DEVICE FOR A CHAIR HAVING A POSITIONABLE BACK COMPRISING IN COMBINATION; A FIRST MEMBER HAVING MEANS FOR ATTATCHMENT TO A CHAIR BASE, A SECOND MEMBER RECTILINEARLY MOVABLE RELATIVE TO THE FIRST MEMBER AND HAVING MEANS FOR ATTACHMENT TO A BACK POSITIONABLE WITH RESPECT TO SAID CHAIR BASE, ONE OF SAID MEMBERS HAVING A FIXED THREADED PART AND THE OTHER OF SAID MEMBERS ROTATABLY CARRYING A PART HAVING THREADING FOR COOPERATION WITH SAID FIXED THREADED PART, SAID THREADED BEING RELATIVELY STEEP SO THAT AN AXIAL FORCED APPLIED BY SAID BACK RECILINERALY BETWEEN SAID FIRST MEMBER AND SAID SECOND MEMBER TENDS TO ROTATE SAID ROTATABLE PART, BRAKE MEANS COOPERABLE WITH A PORTION OF SAID ROTATABLE PART AND SELECTIVELY ENGAGEABLE THEREWITH TO PREVENT ROTATION THEREOF AND TO PREVENT RELATIVE RECTILINEAR MOVEMENT OF SAID FIRST AND SECOND MEMBERS RESPONSIVE TO AN AXIAL LOAD APPLIED BY SAID POSITIONABLE BACK,
Claim 2
Dependent Claim
147 words
A MECHANICAL POSITION-RETAINING DEVICE FOR A CHAIR HAVING A POSITIONABLE BACK COMPRISING IN COMBINATION; A FIRST MEMBER HAVING MEANS FOR ATTATCHMENT TO A CHAIR BASE, A SECOND MEMBER RECTILINEARLY MOVABLE RELATIVE TO THE FIRST MEMBER AND HAVING MEANS FOR ATTACHMENT TO A BACK POSITIONABLE WITH RESPECT TO SAID CHAIR BASE, ONE OF SAID MEMBERS HAVING A FIXED THREADED PART AND THE OTHER OF SAID MEMBERS ROTATABLY CARRYING A PART HAVING THREADING FOR COOPERATION WITH SAID FIXED THREADED PART, SAID THREADED BEING RELATIVELY STEEP SO THAT AN AXIAL FORCED APPLIED BY SAID BACK RECILINERALY BETWEEN SAID FIRST MEMBER AND SAID SECOND MEMBER TENDS TO ROTATE SAID ROTATABLE PART, BRAKE MEANS COOPERABLE WITH A PORTION OF SAID ROTATABLE PART AND SELECTIVELY ENGAGEABLE THEREWITH TO PREVENT ROTATION THEREOF AND TO PREVENT RELATIVE RECTILINEAR MOVEMENT OF SAID FIRST AND SECOND MEMBERS RESPONSIVE TO AN AXIAL LOAD APPLIED BY SAID POSITIONABLE BACK,