Plank unit for inserting into a frame unit of support apparatus

Abstract

A plank unit for inserting into a frame unit is disclosed. The frame unit has a plurality of mortises vertically incrementally arranged at a lateral adjoining edge of a first lateral surface and a second lateral surface thereof. The plank unit includes a support portion and a tenon extending from the support portion configured to be insertable into one of the mortises through the first lateral surface. The support portion is configured to protrude from the second lateral surface upon insertion. The support portion incorporates a biased height arrangement that provides higher degree of height adjustment variation through different insertion orientations, and allows two plank units to be arranged in a vertically adjacent configuration to structurally abut against each other, thereby enhancing structural integrity of the support portion and increasing the load carrying capacity.

What is claimed is: 
     
         1 . A plank unit for inserting into a frame unit, wherein the frame unit includes a first lateral surface, a second lateral surface adjoined the first lateral surface and a plurality of mortises vertically incrementally arranged with substantially equal separation at the adjoining edge of the first lateral surface and the second lateral surface, and the mortises formed between a top frame surface and a bottom frame surface of the frame unit, wherein each mortise constitutes a first side opening accessible from the first lateral surface and a second side opening accessible from the second lateral surface, wherein the first side opening of the mortise is tapered with a first end thereof proximate the second lateral surface being narrower than a second end thereof opposite to the first end, the plank unit comprising:
 a support portion configured to protrude from the second lateral surface upon insertion into the frame unit; and   a tenon portion extending from the support portion configured to be insertable into one of the plurality of mortises through the first lateral surface;   wherein the thickness of the support portion is greater than the width of the mortise defined on the second lateral surface;   wherein upon insertion into a first mortise of the plurality of mortises, an upper support surface of the support portion is substantially flush with an upper boundary of the first mortise, while a bottom support surface of the support portion is substantially flush with an upper boundary of a second mortise immediately below the first mortise.   
     
     
         2 . The plank unit for inserting into a frame unit of  claim 1 , wherein the tenon portion has a cross-sectional shape corresponding to a contour of the first side opening of the mortise. 
     
     
         3 . The plank unit for inserting into a frame unit of  claim 1 , wherein a length of the tenon portion in an insertion direction of the plank unit into one of the plurality of mortises is equal to a length of the second side opening in the insertion direction. 
     
     
         4 . The plank unit for inserting into a frame unit of  claim 1 , wherein the tenon portion has a upper support surface and a lower support surface configured to generate two different height variations depending on the insertion orientation of the plank unit. 
     
     
         5 . The plank unit for inserting into a frame unit of  claim 4 , wherein the support surfaces are arranged to resemble a triangular shape or a circular segment. 
     
     
         6 . The plank unit for inserting into a frame unit of  claim 4 , wherein a height of the mortise is equal to a separation distance between the two neighboring mortises, and the height of the tenon portion is equal to the height of the mortise added with the separation distance between the two neighboring mortises.