Joint

• US 3,879,146 A
• Filed: 01/13/1972
• Issued: 04/22/1975
• Est. Priority Date: 01/15/1971
• Status: Expired due to Term

• Current Assignee: Otto Mayer
• Original Assignee: Otto Mayer
• Inventors: Mayer, Otto
• Primary Examiner(s): Kundrat, Andrew V.
• Application Number:
  US05/217,498
• Time in Patent Office: 1,195 Days
• Field of Search: 287/14,99 297/367,365 16/144 403/93,102
• US Class Current: 403/93
• CPC Class Codes: A47C 1/026 by means of peg-and-notch or pawl-and-ratchet mechanism
• 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
• CPC Class Codes: E05Y 2999/00 Subject-matter not otherwise provided for in this subclass
• CPC Class Codes: E06C 1/32 Ladders with a strut which is formed as a ladder and can be secured in line with the ladder
• CPC Class Codes: Y10T 403/32336 Engaging notch or recess in outer periphery of component

Abstract

A joint having two arms which are pivotable with respect to each other about a common axis, and lockable in at least one predetermined angular position, having a locking member mounted on one arm for radical movement with respect to the joint axis, at least one notch provided on the second arm in a peripheral edge extending concentrically to the joint axis, a spring biasing the locking member towards said peripheral edge, and an unlocking lever pivoted about the joint axis and provided with a substantially eccentric cam facing the locking member and intersecting the peripheral edge of said second arm, wherein the cam merges radially outside the peripheral edge into an end portion which intersects the path of movement of the locking member at right angles when the unlocking lever is disposed in an unlocked position.

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:

a locking member mounted on one arm for radial movement with respect to the joint axis;

a peripheral edge on the second arm extending concentrically from the joint axis and having a plurality of notches formed on the edge;

spring means biasing said locking member towards said peripheral edge, an unlocking lever pivoted about the joint axis relative to the joint arms and having a substantially eccentric control curve for engaging said locking member and rising above the peripheral edge of the second arm, wherein the control curve includes a lift portion which in the locked condition of the joint, faces one of the notches and increases eccentrically its center distance, and when above the periphral edge the control curve passes through a point of maximum center distance and then in a blocking portion remote from the notches in the locked condition of the joint, the center distance thereof decreasing to form a cam portion, the unlocking movement of said unlocking lever relative to the second joint arm being limited so that the blocking portion upon reaching the end position of the unlocking lever in its unlocking position faces the notches and crosses said peripheral edge radially outward in the region of the notches, one of the notches in said peripheral edge of the second arm being radially aligned with said locking member when in one end position of the joint, and having a rear flank bevelled for receiving the locking member during rotation of the second arm into the other end position of the joint so that during rotation, said locking member can slide on and out the rear flank, and means for frictionally connecting said unlocking lever to the second joint arm.

2. The joint as claimed in claim 1 wherein said unlocking lever in its locking position bears in the direction opposite to its unlocking movement on the second joint arm, a cam stop formed on the end portion of the control curve and engaging the locking member in the direction of the unlocking movement of the unlocking lever when the unlocking lever has reached its unlocking position, a cam-like projection formed on said second arm and extending radially further from the joint axis than said cam stop and disposed so that said cam-like projection reaches the region of the locking member before the second joint arm reaches the unlocking lever when the joint is unlocked during the pivotal movement of the second joint arm directed against (the) said unlocking lever.

3. The joint as claimed in claim 1 comprising an axial biasing spring pressing said unlocking lever and the second joint arm against each other, axial projections formed in the contacting side faces of said unlocking lever and the second joint arm to increase the force of the biasing spring in a certain angular position of the unlocking lever in contact with the second joint arm.