Motorized CAT 963D Track Loader with Lego PF and SBrick Control

After installing or modifying a few models, it was the time to take up some challenges.  I chose CAT 963D not only it was related to my work but also there were a few models had been posted in the internet so I could make reference.  Among the several models, Makorol's model posted in 2012 was regarded as the best by many people, but he only posted with 20+ photos and a YouTube video.  Nonetheless, it was better than nothing and I could make reference by counting the number of bricks to measure the dimensions.

In the beginning, I had no clue on how to start but ordering a large number of bricks and plates with different lengths and shapes.  It took me a whole month and a few times to order and have the bricks and plates I needed.

Undercarriage

To make the undercarriage was not difficult as it was similar to those Lego Technic's.  I used two PF motors and one PF controller to control two tracks so that they could turn independently.

Upper Structure & Cab

It was not very difficult as they were not required to be a strong structure.  However making sure you used different shapes of bricks and plates to reinforce the structure and used nail polish if necessary.  

The structure to support the lifting arms' push rods and motors was another story.  Each push rod was driven by a PF motor through a universal joint.  As the push rods were supporting the weight of the lifting arms and bucket, it must be strong and solid, so I used glue to reinforce the structure.  

Lifting Arms & Bucket

It looked very simple but you needed to try different lengths to make a smooth lifting up and down motion.  

IR Remote Control

I used two PF remote controllers to control two tracks, lifting arm's up and down, and bucket curling.  To have enough space to house the battery case at the back, I put one PF controller at the front which was beneath the lifting arm structure.  The compact battery case was nicely installed at the back of the engine compartment.  The engine compartment room can be opened to take out the battery case for batteries replacement. 

SBrick Control
As I hand a spare SBrick, I later modified the model with SBrick control.

Motorized CAT 963D Track Loader

自從砌過及改裝過幾套模型後，決定向高難度挑戰。選擇CAT 963D除了是與自己職業有關之外，尚有這個模型已經有人在網上發佈過，可以用作參考。數個在網上發表的作品中，以2012年Makorol發表的最神似，但只提供了20多張照片及壹段Youtube短片，並沒有提供Build Instruction。但有照片都好過無，起碼數磚頭大概都知道模型的尺寸，我的作品亦以此為藍本。

開始時真係無從開始，看完網上照片後定了壹大堆不同尺寸的Brick及Plate回來，一路砌一路定，前後定了四次及壹個月時間才定齊大部份所需的積木。

底盤
首先就是砌個底盤出來，玩過Technic模型的都應該知道難度不大。由於兩條履帶需獨立驅動，所以用上兩個M馬達來驅動及壹個PF控制器。

上座及駕駛室
難度不算太大，上座結構及駕駛室都不是食力部份，儘量用不同尺寸的Brick及Plate來加強結構的強度，甚至使用了透明指甲油去增加黏貼力。
反而用來推動鏟臂的兩條推杆及推動鏟斗的推杆的結構比較棘手。每組推杆都是由壹個M馬達驅動，通過壹個萬向軸聯接推杆，由於這幾支推杆需承擔鏟臂及錘斗的重量，所以整個結構必須要好穩固，這部份需用膠水來鞏固結構。

鏟臂及鏟斗
這部份看似簡單，其實要不斷嘗試鏟臂及鏟斗連接杆的尺寸，以便得出比較順滑的鏟臂升降及鏟斗前後傾的動作。

IR遙控系統
今次用了兩個PF接收器，用作控制兩條履帶，錘鏟臂升降及鏟斗前後傾的動作。壹個裝在機前，壹個機尾以節省機尾的空間。兩個發射器左邊那個控制鏟臂及鏟斗，右邊那個控制兩條履帶。電源由壹個小型電池盒提供，剛好可以放入機尾內。

SBrick Control
見有個士啤SBRick，於是著手改裝。壹個SBrick可以代替兩個PF控制器，可控制四個馬達。