Rev 3870 Rev 3876
-   1 use <library.scad>
-   2  
1 Clear=0.175; // size of tolerance zone 3 Clear=0.175; // size of tolerance zone
2 thickness = 2; // global wall thickness 4 thickness = 2; // global wall thickness
3 height = 15; // height of one screen element 5 height = 15; // height of one screen element
4 screen_radius = 75/2; // outer radius of screen 6 screen_radius = 75/2; // outer radius of screen
5 tube_radius=30/2; // inner radius of the space for a sensor 7 tube_radius=30/2; // inner radius of the space for a sensor
6 screen_bevel = 10; // bevel of outer screen wall 8 screen_bevel = 10; // bevel of outer screen wall
7 num_ribs = 3; // number of holding ribs 9 num_ribs = 3; // number of holding ribs
8 cap_radius = screen_radius * 1.5; 10 cap_radius = screen_radius * 1.5;
9 inner_ring_thickness = thickness *2; 11 inner_ring_thickness = thickness *2;
10   12  
11   13  
12 angle_sep = 360/num_ribs; 14 angle_sep = 360/num_ribs;
13   15  
14 cap_height = cap_radius - sqrt(cap_radius*cap_radius - (screen_radius - screen_bevel)*(screen_radius - screen_bevel)); 16 cap_height = cap_radius - sqrt(cap_radius*cap_radius - (screen_radius - screen_bevel)*(screen_radius - screen_bevel));
15   17  
16 difference () { 18 difference () {
17   19  
18 union() { 20 union() {
19 //cap outer shell 21 //cap outer shell
20 intersection () { 22 intersection () {
21 translate ([0,0,-cap_radius + height + cap_height]) 23 translate ([0,0,-cap_radius + height + cap_height])
22 sphere(cap_radius, $fn=100); 24 sphere(cap_radius, $fn=100);
23   25  
24 //screen outer shell 26 //screen outer shell
25 cylinder (h=screen_radius*(height/screen_bevel),r1=screen_radius ,r2=0,$fn=100); 27 cylinder (h=screen_radius*(height/screen_bevel),r1=screen_radius ,r2=0,$fn=100);
26 } 28 }
27   29  
28 // cap hook 30 // cap holder
29 translate ([0,0,height + (cap_height-thickness)]) 31 translate ([0,0,height + (cap_height-thickness)])
30 difference () { -  
31 cylinder (h=height/2,r1=screen_radius/4,r2=screen_radius/4 - thickness,$fn=100); -  
32   -  
33 translate ([0,screen_radius/4,2.5]) -  
34 rotate ([90,0,0]) -  
35 cylinder (h=screen_radius/2,r=3, $fn=100); -  
36   -  
37 translate ([-screen_radius/4,0,2.5]) -  
38 rotate ([0,90,0]) -  
39 cylinder (h=screen_radius/2,r=3, $fn=100); 32 screen_holder(height, screen_radius, thickness);
40 } -  
41   33  
42   34  
43 } 35 }
44   36  
45 union() { 37 union() {
46 intersection () { 38 intersection () {
47 //cap inner cavity 39 //cap inner cavity
48 translate ([0,0,-cap_radius + height + cap_height ]) 40 translate ([0,0,-cap_radius + height + cap_height ])
49 sphere(cap_radius-thickness, $fn=100); 41 sphere(cap_radius-thickness, $fn=100);
50   42  
51 //screen inner cavity (height is solved by triangle similarity) 43 //screen inner cavity (height is solved by triangle similarity)
52 translate ([0,0, -Clear/2 ]) 44 translate ([0,0, -Clear/2 ])
53 cylinder (h=(screen_radius - thickness)*(height/screen_bevel),r1=screen_radius - thickness ,r2=0,$fn=100); 45 cylinder (h=(screen_radius - thickness)*(height/screen_bevel),r1=screen_radius - thickness ,r2=0,$fn=100);
54 } 46 }
55 } 47 }
56 } 48 }
57   49  
58   50  
59   51  
60 // center ribs 52 // center ribs
61 for (i = [0 : (num_ribs-1)]) { 53 for (i = [0 : (num_ribs-1)]) {
62 rotate ([90,0,angle_sep * i]) 54 rotate ([90,0,angle_sep * i])
63 translate ([0,0,-thickness/2]) 55 translate ([0,0,-thickness/2])
64 linear_extrude (height = thickness, convexity = 10) 56 linear_extrude (height = thickness, convexity = 10)
65 polygon(points=[[0, cap_height + height],[tube_radius + thickness - Clear, 0],[screen_radius - thickness,0],[screen_radius - screen_bevel - thickness,height]]); 57 polygon(points=[[0, cap_height + height],[tube_radius + thickness - Clear, 0],[screen_radius - thickness,0],[screen_radius - screen_bevel - thickness,height]]);
66   58  
67 } 59 }