Collect parts and tools for Cascading string assembly. This guide builds a four-stage lift with a surgical Tubing (REV-41-1163) return. These parts are not included in the Linear Motion Kit v2 (REV-45-1507). You will also need the completed Basic Slide Assembly.
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Steps
Step 1
Drop the locknut (REV-41-1361) into the slot on the top of the endcap. Slide the bolt through the pulley (REV-41-1368), pulley cover, and the endcap. Thread the bolt into the locknut and make sure you thread far enough into the endcap to have the end of the bolt supported by the endcap. This will act as a cantilever support and add strength to the pulley axle when it is under load.
Step 2
Add a pulley to the top of the first three extrusions. All pulleys must be on the same side of the assembled linear motion system.
Step 3
Repeat the previous step for the bottom of the last three extrusion pieces, but don’t add the pulley or the pulley cover.
On the bottom of the first piece of extrusion, add a M3 x 16mm bolt (REV-41-1360) and locknut by sliding the bolt into the extrusion channel. Secure it into place.
Step 4
Assemble Lift by securely attaching the stationary first stage extrusion to the frame of your robot using REV plastic or metal brackets.
Position a motor on the side next to the extrusion mounted to the frame.
Note: The motor needs a winding spool attached to it. Attachment of the pulley will vary depending on motor type. In this example, the REV Core Hex Motor (REV-41-1300) has a 5mm Hex Shaft with a spool held in place with a pair of Shaft Collars (REV-41-1327).
Step 5
Attach a length of String (REV-41-1162) to the bolt post on the bottom of second stage. Run the string over the pulley at the top of the first stage and down to the winding spool. Secure the string onto the winding spool.
The line may be hard to get onto the pulley with the pulley cover attached, but it is not impossible.
An easier but more time-consuming alternative to get the line onto the pulley is to remove the pulley axle bolt and slip the pulley out from inside the pulley cover. Attach the line around the pulley and slide it back into the pulley cover and reinsert the bolt and tighten.
Step 6
Attach a length of string to the bolt post on the bottom of first stage. Run the string over the pulley at the top of the second stage. Attach the string to the bolt post at the bottom of the third stage.
Step 7
Attach a length of string to the bolt post on the bottom of second stage. Run the string over the pulley at the top of the third stage. Attach the string to the bolt post at the bottom of the fourth stage.
Step 8
To set up the surgical tubing return system, add bolts on the back side of the endcaps from where you just attached the drive lines. The bolts will mount just like the anchor bolts for the drive lines you mounted earlier in Step 3. Mount one at the base of the first piece of extrusion, and two more in each of the first two end caps.
Step 9
Add bolts to the second and third endcaps like the last step, and a third at the top of the last stage, similarly to the last step as well.
Step 10
Push a screw into an end of the surgical tubing.
Step 11
With string tightly wrap the surgical tubing onto the screw and tie it off. Then tie a loop of string such that the loop can be hooked over a screw post.
*alternatively, you can simply tie an end loop knot in the end of the surgical tubing.
Step 12
On the back side of the lift, opposite the drive lines, attach 3 surgical tube lengths to the anchor bolts in the end caps in an arrangement seen left.
Adjust the length of each piece to adjust the force that pulls the lift down. For a starting point, the surgical tubing should be just slightly in tension when the lift is in the closed position.
Done
