AUTOMATICALLY INTERLOCKABLE HINGE FITTING

• US 3,643,292 A
• Filed: 08/21/1969
• Issued: 02/22/1972
• Est. Priority Date: 08/23/1968
• Status: Expired due to Term

• Current Assignee: Otto Mayer
• Original Assignee: Otto Mayer
• Inventors: Mayer, Otto
• Primary Examiner(s): Gilliam, Paul R.
• Application Number:
  US04/851,974
• Time in Patent Office: 915 Days
• Field of Search: 16/144,147
• US Class Current: 16/325
• CPC Class Codes: A47C 1/026 by means of peg-and-notch or pawl-and-ratchet mechanism
• 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: F16C 11/10 Arrangements for locking
• CPC Class Codes: F16C 2350/00 Machines or articles related to building in general E01 - E06
• CPC Class Codes: Y10T 74/20636 Detents
• CPC Class Codes: Y10T 74/2133 Pawls and ratchets

Abstract

A lockable hinge fitting which usually forms part of folding ladders, reclining chairs, etc., in which a pair of hinge arms are connected one to the other turnable round a common axis. One hinge arm carries a spring-loaded locking member which in its operative position locks the hinge fitting in a desired angular position by engaging one of a number of recesses circumferentially spaced apart from each other on the periphery of the other hinge arm. An unlocking lever is provided to move the locking member into its inactive position where the locking member is locked by a pawl. The pawl can be moved into its operative position in which it locks the locking member in its inactive position by pawl-actuating means during the movement of the unlocking lever in its unlocking position. This pawl actuating means is preferably an integral part of the unlocking lever or the pawl. According to the different attachments of the hinge fitting, the pawl will either release the locking member in any subsequent angular position defined by a recess or only when a suitable pivotable movement of the hinge fitting is performed. In both cases, the interlocking is performed automatically.

Claims

1. An automatically lockable hinge fitting, comprising;

a first hinge arm pivotably mounted about a hinge axis;

a second hinge arm, pivotably mounted about said hinge axis, having a circular portion concentric with respect to said hinge axis and at least one recess provided in the peripheral portion thereof;

a movably mounted, spring-loaded locking member carried by said first hinge arm and slidably guided therein substantially radially with respect to said hinge axis, said locking member being biased to engage in an operative position said recess provided in said second hinge arm and thereby define preferred angular positions of both of said hinge arms;

an unlocking member, pivotably and coaxially mounted with respect to said hinge axis and pivotable between a first and second position, said unlocking member having a cam surface provided thereon which abuts said locking member and moves said locking member to an inoperative position in which it is disengaged from said second hinge arm as said unlocking member is pivoted from its first to its second position;

a pawl, pivotably and coaxially mounted with respect to said hinge axis, and movable into and out of engagement with said locking member when said locking member is situated in its inoperative position, said pawl being frictionally coupled to said second hinge arm so as to provide common movement therewith with respect to said hinge axis, and being bifurcated at its outer end so as to provide pawl arms at both sides of said locking member and a recess at the outer end of said pawl, the contour of said recess substantially conforming in its inner portion to the contour of said locking member and widening in its outer portion to form a shoulder in the pawl arm situated on the side of said locking member which is approached when said unlocking member is pivoted from its first to its second position, the radial distance between said shoulder and said hinge axis being longer than the radius of the periphery of said circular portion of said second hinge arm; and

a pawl abutment member, affixed to said unlocking member and disposed in the pivotable path of said pawl, for engaging and moving said pawl into locking engagement with said locking member wheNever said locking member is situated in its inoperative position, said abutment member engaging said pawl during movement of said unlocking member from its first to its second position, a catch pivotably mounted on said first hinge arm engaging one arm of said pawl, and a cam surface provided on said second hinge arm, for engaging said catch and pivoting said pawl when said first and second hinge arms approach 180* alignment, and thereby aligning said recess provided in said pawl with said locking member and allowing said locking member to be received by said recess so as to lock said first and second hinge arms with respect to each other, a second pawl, pivotably and coaxially mounted with respect to said hinge axis and frictionally coupled to said second hinge arm, the outer end of said second pawl being bifurcated so as to provide pawl arms at both sides of said locking member and a recess at said outer end, the contour of said recess substantially conforming in its inner portion to the contour of said locking member and widening in its outer portion to form a shoulder in the pawl arm situated at the side of said locking member which is approached by said second pawl when said second hinge arm is pivoted, the radial distance between said shoulder of said second pawl and said hinge axis being shorter than the radial distance between said shoulder of said first pawl and said hinge axis, but longer than the radius of the periphery of said circular portion of said second hinge arm, said recess in said second pawl being wider than said recess in said first pawl in the range of said shoulders, said pawl arm of said second pawl which is opposite said pawl arm provided with said shoulder being provided with a flank extending from the inner end of said recess substantially obliquely with respect to the radial direction about said hinge axis, in order to widen said recess at its outer portion so that during the movement of said locking member from its inoperative position to its operative position, said locking member contacts said flank and pivots said second pawl into a position suitably aligned with respect to said locking member, in which aligned position said pawl arm provided with said flank is moved out of the range of said shoulder which is provided in said pawl arm of said first pawl.

2. An automatically lockable hinge fitting, comprising;

a first hinge arm pivotably mounted about a hinge axis, a second hinge arm, pivotably mounted about said hinge axis, having at least one recess provided in a circular, peripheral portion thereof, a movably mounted, spring-loaded locking member, carried by said first hinge arm, biased to engage in an operative position said recess provided in said second hinge arm and define thereby preferred angular positions of both of said hinge arms, an unlocking member, movably mounted about said hinge axis, and pivotable between a first and second position, said unlocking member including a cam surface which abuts said locking member and moves said locking member into an inoperative position in which it is disengaged from said second hinge arm as said unlocking member is pivoted from its first position to its second position, and a pawl, pivotably mounted on an axle parallel with said hinge axis, and movable into and out of engagement with said locking member when said locking member is situated in its inoperative position, said pawl being frictionally connected with said second hinge arm for common movement therewith with respect to said hinge axis, and bifurcated so as to provide pawl arms at both sides of said locking member and a recess at the outer end of said pawl which cooperates with said locking member, the contour of said recess substantially conforming in its inner portion to the contour of said locking member and widening at its outer portion to form a shoulder on one of said pawl arms on said pawl, the radial distance between said shoulder and said hinge axis being longer than the radius of the periphery of said circular portion of said hinge arm, and a face cam on the other pawl arm of said pawl, said cam cooperating with said locking member during movement into its inoperative position and transmitting movement to said pawl during movement of said locking member, so that a stop face provided on said pawl is moved into the path of said locking member, a second, pivotably mounted pawl, the outer end of which is bifurcated so as to provide pawl arms at both sides of said locking member and a recess at the outer end of said second pawl which cooperates with said locking member, the contour of said recess substantially conforming in its inner portion to the contour of said locking member and widening in its outer portion to form a shoulder at each pawl arm of said second pawl, said recess being wider than the recess in said first pawl, said shoulder of said second pawl being disposed on the side of said pawl being disposed on the side of said pawl corresponding to said shoulder provided on said first pawl, and said shoulder of said second pawl being disposed on the side of said first pawl provided with said surface cam and having a shorter distance from said hinge axis than the other shoulder of second pawl, said circular portion of said second hinge arm includes a plurality of recesses on its periphery, the last one of said recesses having a lateral edge which is inclined and ascends towards the periphery of said circular portion, a cam being provided on said periphery at the point at which said inclined edge ends, the top of which has a longer distance from said hinge axis on said first shoulder of said second pawl, said first shoulder and said inclined edge of said recess being situated at the same side of said second pawl and said recess, respectively.