LOCKABLE HINGE JOINT

• US 3,849,834 A
• Filed: 02/09/1973
• Issued: 11/26/1974
• Est. Priority Date: 02/11/1972
• Status: Expired due to Term

• Current Assignee: Otto Mayer
• Original Assignee: Otto Mayer
• Inventors: Mayer, Otto
• Primary Examiner(s): Gilliam, Paul R.
• Assistant Examiner(s): Troutman, Doris L.
• Application Number:
  US05/330,900
• Time in Patent Office: 655 Days
• Field of Search: 16/144,145 287/99,14
• US Class Current: 16/332
• CPC Class Codes: E05D 11/081 with both radial and axial friction, e.g. conical friction surfaces
• CPC Class Codes: E05D 11/1028 for maintaining the hinge in two or more positions, e.g. intermediate or fully open

Abstract

A hinge joint having two arms rotatable about a common axis is lockable in at least one predetermined position. The apparatus includes a locking ratchet engaging locking detents formed on the peripheral edge of one of the arms. A spring tensions the ratchet towards the locking detents. A release lever, tensioned against an arm side, rotates about the common axis. Said lever includes a cam profile substantially eccentric in relation to its center and rises to a first release face ending at a high point outside said peripheral edge. It then slopes downward forming a blocking sector. The blocking sector is substantially concentric and slightly below said peripheral edge. The cam profile then turns inward forming a second release face finally droping downward to form abutting surface. A stop bar positioned within one of the rotational arms confines rotation of the release lever. The locking ratchet engages the detents according to the relative position of said release lever about the common axis so as to lock the joint arm.

Claims

1. A joint having two arms pivotable about a common axis and lockable with respect to each other in at least one predetermined angular position comprising:

locking means mounted within a first arm for radial movement with respect to the common axis;

a peripheral edge on the second arm extending concentrically about the common axis and haVing at least one locking detent formed thereon;

biasing means for urging said locking means towards said peripheral edge;

a release lever pivotable about the common axis relative to the arms and having a cam profile including an eccentric portion in relation to its center and rising to a first release face to a high point outside said peripheral edge, a blocking sector portion following the high point and substantially concentric and slightly below said peripheral edge, a second release face following the blocking sector portion, and an abutting surface for confining the rotation of said release lever; and

stop means positioned in the second arm for limiting the movement of said release lever relative to the second arm so that the travel of said release lever ends when the abutting surface strikes said stop means preventing the cam high point from engaging said locking means when an unlocking action is performed by said second release face.

2. The joint as recited in claim 1, further comprising at least three locking detents in the second arm, and a radial projection on said peripheral edge positioned between the second and third detents so that as said release lever abuts against said stop means so that said projection overrides the cam high point.

3. The joint as recited in claim 1, wherein said locking means comprises:

A guide integrally formed within the first arm and directed radially towards said peripheral edge, and a ratchet moveable in said guide and having rounded edges capable of engaging the locking detents.

4. The joint as described in claim 1, additionally comprising means for frictionally coupling said release lever to the second arm so that at predetermined intervals said release lever rotation is independent of the rotation of the second arm.

5. The joint as recited in claim 4, wherein means for frictionally coupling comprises a rotatable bushing disposed about the common axis, and spring means for biasing said release lever against the inside of the second arm.

6. The joint as recited in claim 1, further comprising re-enforcing members fixed adjacent to the second arm and having locking detents in accurate registration with the detents of the arm.

7. The joint as recited in claim 3, wherein said biasing means comprises a tension spring urging said ratchet towards said peripheral edge.