Adjust platform arm and deck dimensions for bracket width

Updated calculations for platform arm length and deck depth to account for half the pivot bracket width. Modified related translations and extrusions in SCAD files to ensure correct assembly alignment.

Author: dorkmo

LifeTrac-v25/mechanical_design/openscad/lifetrac_v25.scad

@@ -2442,7 +2442,7 @@ module platform_angle_iron() {
 
     difference() {
         // Extrusion
-        linear_extrude(height=PLATFORM_ARM_LENGTH)
+        linear_extrude(height=PLATFORM_ARM_LENGTH - PLATFORM_BRACKET_WIDTH/2)
         polygon([
             [0, 0],
             [PLATFORM_ANGLE_LEG, 0],
@@ -2593,7 +2593,7 @@ module folding_platform_assembly(fold_angle=90) {
         translate([0, pivot_y, pivot_z - 60])
         rotate([fold_angle, 0, 0])  // Same rotation as angle irons
         // Deck sits on top of angle iron horizontal legs
-        translate([0, PLATFORM_THICKNESS/2, arm_deck_bolt_dist])
+        translate([0, PLATFORM_THICKNESS/2, PLATFORM_DEPTH/2 - PLATFORM_BRACKET_WIDTH/2])
         rotate([90, 0, 0])  // Rotate deck to be horizontal in local coords
         platform_deck();
 

LifeTrac-v25/mechanical_design/openscad/lifetrac_v25_params.scad

@@ -169,10 +169,14 @@ DECK_HEIGHT = 250;  // Height above ground
 // 5-component folding platform: 1x deck plate + 2x pivot brackets + 2x angle arms
 // Folds from stowed (vertical against rear) to deployed (horizontal)
 
+// --- Pivot bracket dimensions ---
+PLATFORM_BRACKET_LENGTH = 150;  // Length of pivot bracket plate (mm)
+PLATFORM_BRACKET_WIDTH = 100;   // Width of pivot bracket plate (mm)
+
 // --- Configurable dimensions ---
 PLATFORM_THICKNESS = PLATE_1_4_INCH;  // Deck plate thickness
-PLATFORM_DEPTH = 400;           // Front-to-back depth of deck (mm)
 PLATFORM_ARM_LENGTH = 350;      // Length of angle iron arms (mm)
+PLATFORM_DEPTH = PLATFORM_ARM_LENGTH + PLATFORM_BRACKET_WIDTH/2;           // Front-to-back depth of deck (mm)
 PLATFORM_PIVOT_HEIGHT = 250;    // Height of pivot point / deck surface when deployed (mm)
 
 // --- Derived dimensions (calculated from frame geometry) ---
@@ -193,10 +197,6 @@ _INNER_PANEL_X = TRACK_WIDTH/2 - SANDWICH_SPACING/2;  // = 450 - 60 = 390mm
 PLATFORM_PIVOT_X_INSET = 0;  // Distance inward from inner panel face (mm)
 PLATFORM_PIVOT_X = _INNER_PANEL_X - PLATFORM_PIVOT_X_INSET;  // X position of pivot from center (~390mm)
 
-// --- Pivot bracket dimensions ---
-PLATFORM_BRACKET_LENGTH = 150;  // Length of pivot bracket plate (mm)
-PLATFORM_BRACKET_WIDTH = 100;   // Width of pivot bracket plate (mm)
-
 // --- Hardware dimensions ---
 PLATFORM_PIVOT_PIN_DIA = BOLT_DIA_1;    // 1" (25.4mm) pivot pin diameter
 PLATFORM_LOCK_PIN_DIA = 9.525;          // 3/8" (9.525mm) cotter/lock pin diameter

LifeTrac-v25/mechanical_design/openscad/parts/platform_angle_arm.scad

@@ -33,7 +33,7 @@ include <../lifetrac_v25_params.scad>
  */
 module platform_angle_arm(show_holes=true) {
     // Local variables for clarity
-    length = PLATFORM_ARM_LENGTH;
+    length = PLATFORM_ARM_LENGTH - PLATFORM_BRACKET_WIDTH/2;
     leg = PLATFORM_ANGLE_LEG;        // 50.8mm (2")
     thick = PLATFORM_ANGLE_THICK;    // 6.35mm (1/4")