Articulating support mechanism with pivotal brake shoe

Abstract

A four bar articulating support mechanism has four pivot axes with one of the pivot axes being movable relative to a linkage of the support arm. The linkage has at least two arcuate slots therein that receive a pin. As the linkage is moved vertically relative to a mounting member, the pin slides in the at least two arcuate slots which pivot about a theoretical third pivot axis. The support arm has two brake shoes that are pivotally mounted on a mounting member, the brake shoes having a locking surface that corresponds to a locking surface on the linkage. The mechanism operates on a parallelogram linkage.

1 . An articulating support mechanism for use in supporting one or more objects on a platform, said mechanism being usable with a base, said mechanism comprising a linkage having a first end and a second end with a mounting member being pivotally connected to said linkage at said first end and said platform being pivotally connected to said linkage at said second end, said linkage having an upper arm and a lower arm, said upper arm being pivotally connected to said mounting member at a first pivot axis and being pivotally connected to said platform at a second pivot axis, said lower arm having at least one arcuate slot that is connected to said mounting member to enable said lower arm to pivot about a third pivot axis, said lower arm being pivotally connected to said platform at a fourth pivot axis, said pivot axes being parallel to one another, said mounting member being sized and shaped to be mounted on said base and to receive said first end of said linkage, said mounting member and said upper arm being constructed to pivot relative to one another about said first pivot axis, a pin extending through said mounting member and through said at least one arcuate slot in said lower arm, said third pivot axis being located along an imaginary line about which said at least one arcuate slot pivots when said linkage moves vertically relative to said mounting member, said pin being slidable in said at least one arcuate slot, said first, second, third and fourth pivot axes being in a parallelogram configuration at all times, a brake shoe being pivotally mounted on said mounting member about a fifth pivot axis, said brake shoe and said linkage having locking surfaces thereon that removably lock with one another in infinite positions of said linkage relative to said mounting member, said linkage locking by gravitational forces and being releasable by an upward force on said linkage or on said platform or by manually tilting said platform upward, said platform being pivotable relative to said linkage independently of said platform and said linkage pivoting relative to said mounting member. 
   
   
       2  A support mechanism as claimed in  claim 1  wherein said pin in said at least one arcuate slot being in a non-parallelogram configuration with said first, second, and fourth pivot axes. 
   
   
       3 . A support mechanism as claimed in  claim 2  wherein said mounting member, upper arm, and lower arm, each have two sides and said at least one arcuate slot in said lower arm, being two arcuate slots, one arcuate slot being located on each side of said lower arm. 
   
   
       4 . A support mechanism as claimed in  claim 3  wherein said arcuate slots of said lower arm are first arcuate slots, said first arcuate slots being equidistant from said third pivot axis. 
   
   
       5 . A support mechanism as claimed in  claim 4  wherein said third pivot axis is theoretical, there being no pin located at said third pivot axis. 
   
   
       6 . A support mechanism as claimed in  claim 4  wherein said upper arm has two second arcuate slots, there being one second arcuate slot in each side of said upper arm, said second arcuate slots being oriented about said first pivot axis. 
   
   
       7 . A support mechanism as claimed in  claim 4  wherein said arcuate slots in said lower arm have a heat tempered insert lining said slot on each side of said lower arm, there being two inserts. 
   
   
       8 . A support mechanism as claimed in  claim 3  wherein said arcuate slots in said lower arm are oriented about said third pivot axis, said third pivot axis being a theoretical pivot axis for said mounting member and said lower arm. 
   
   
       9 . A support mechanism as claimed in  claim 3  wherein said first pivot axis is further from an outer end of said linkage than said third pivot axis. 
   
   
       10 . A support mechanism as claimed in  claim 1  wherein said brake shoe has a curved locking surface that is oriented to correspond to a locking surface of said upper arm. 
   
   
       11 . A support mechanism as claimed in  claim 10  wherein said locking surface of said brake shoe frictionally engages with said locking surface of said upper arm to lock said mounting member relative to said linkage. 
   
   
       12 . A support mechanism as claimed in  claim 11  wherein said locking surface on said brake shoe is curved inward and a locking surface on said upper arm is curved outward. 
   
   
       13 . A support mechanism as claimed in  claim 12  wherein said brake shoe is heat tempered. 
   
   
       14 . A support mechanism as claimed in  claim 13  wherein said brake shoe is a first brake shoe that is pivotally mounted on one side of said bracket and there is a second brake shoe pivotally mounted on an opposite side of said bracket. 
   
   
       15 . A support mechanism as claimed in  claim 7  wherein said platform can be pivoted relative to said linkage independently of said linkage pivoting relative to said mounting member. 
   
   
       16 . A support mechanism as claimed in  claim 14  wherein said second brake shoe is a mirror image of said first brake shoe. 
   
   
       17 . A support mechanism as claimed in  claim 1  wherein said brake shoe has an orientation interface that interacts with a surface of said lower arm to cause said brake shoe to lock with said upper arm. 
   
   
       18 . A support mechanism as claimed in  claim 14  wherein said brake shoes each have an activation surface that abuts a corresponding activation surface on said lower arm to pivot said brake shoes to maintain said locking surfaces in alignment. 
   
   
       19 . An articulating support mechanism for use in supporting one or more objects on a platform, said mechanism being usable with a base, said mechanism comprising a linkage having a first end and a second end, with a mounting member being pivotally connected to said linkage at said first end and said platform being pivotally connected to said linkage at said second end, said linkage having an upper arm and a lower arm, said upper arm being pivotally connected to said mounting member at a first pivot axis and being pivotally connected to said platform at a second pivot axis, said lower arm being slidably connected to a pin extending through said mounting member and into at least one arcuate slot in said lower arm to enable said lower arm to pivot about a third pivot axis, said lower arm being pivotally connected to said platform at a fourth pivot axis, said pivot axes being parallel to one another, and said mounting member being sized and shaped to be mounted on said base, said first and second and fourth pivot axes and said pin having a non-parallelogram configuration, said first, second, third and fourth pivot axes having a parallelogram configuration at all times, said third pivot axis being imaginary, a brake shoe being pivotally mounted on said mounting member about a fifth pivot axis, said brake shoe and said linkage having locking surfaces thereon that removably lock with one another in infinite positions of said linkage relative to said mounting member, said linkage locking by gravitational forces and being releasable by an upward force on said linkage or on said platform or by manually tilting said platform upward, said platform being pivotable relative to said linkage independently of said platform and said linkage pivoting relative to said mounting member. 
   
   
       20 . A support mechanism as claimed in  claim 19  wherein said mounting member, upper arm, and lower arm each have two sides and said at least one arcuate slot in said lower arm, being two arcuate slots, one arcuate slot being located on each side of said lower arm. 
   
   
       21 . A support mechanism as claimed in  claim 20  wherein said arcuate slots of said lower arm are first arcuate slots, said first arcuate slots being oriented about said third pivot axis, there being no pin located at said third pivot axis. 
   
   
       22 . A support mechanism as claimed in  claim 21  wherein said upper arm has two second arcuate slots, there being one second arcuate slot in each side of said upper arm, said second arcuate slots being oriented about said first pivot axis. 
   
   
       23 . A support mechanism as claimed in  claim 21  wherein said arcuate slots in said lower arm each have a heat tempered insert lining said slot, there being two inserts. 
   
   
       24 . An articulating support mechanism for use in supporting one or more objects on a platform, said mechanism being usable with a base and comprising a linkage having two ends with a mounting member at one end and a platform at an opposite end, with two pivot axes at each end, said pivot axes being parallel to one another, said mounting member being sized and shaped to be mounted on said base, said linkage having an upper arm and a lower arm, said upper arm having a first pivot axis with said mounting member and a second pivot axis with said platform, said lower arm having a third pivot axis with said mounting member and a fourth pivot axis with said platform, said mechanism having a pin extending through said mounting member and through at least one arcuate slot, said at least one arcuate slot being located on said lower arm, said at least one arcuate slot in said lower arm pivoting about said third pivot axis and said pin sliding in said at least one arcuate slot as said linkage moves vertically relative to said mounting member, said third pivot axis being located along an imaginary line, a brake shoe being pivotally mounted on said mounting member about a fifth pivot axis, said brake shoe and said linkage having locking surfaces thereon that removably lock with one another in infinite positions of said linkage relative to said mounting member. 
   
   
       25 . A support mechanism as claimed in  claim 24  wherein said mounting member, upper arm, and lower arm, each have two sides and said at least one arcuate slot in said lower arm, being two arcuate slots, one arcuate slot being located on each side of said lower arm.