"No Programming" Method of Winding Onto a Tapered Flange Spool

by Bob Jeter, Applications Engineer, Amacoil, Inc.

Fig. 1: Typical winding setup.

In a basic winding setup, as seen in Figure 1, there is a traversing assembly that includes a linear actuator. Attached to the actuator is the material guide through which passes the wire, cable or other material that is being spooled. As the linear actuator traverses a preset stroke length, it moves the material back and forth across the spool core for even placement of lay lines.

The reciprocating movement of the traversing assembly in this basic winding setup readily accommodates cylindrical spools with flanges that are at right angles to the spool core. But if the spool flanges are angled or tapered outward, special linear movement requirements are placed on the traversing assembly.

Fig. 2: Winding material onto a tapered flange spool requires a controlled change in linear actuator stroke length.

In this case, after the center core of the spool (between the flanges) fills up, the material must be wound onto the tapered flange surfaces. Linear actuator stroke length must gradually increase (Figure 2) without affecting the actuator's pitch (linear distance traveled per shaft revolution). The pitch, which is based on the diameter of the material being spooled, must remain constant for even, side-by-side placement of lay lines.

How can this be accomplished? Programmable, electronically controlled winding setups are commonly employed to meet the application requirements for winding material onto a tapered flange spool. This method requires various types of motors, encoders and motion controllers (Figure 3).

Fig. 3: Programmable winding system.

However, it is often desirable to avoid the programming approach and thereby simplify system design, operation and maintenance. This is achieved by using a mechanical method of increasing the actuator's stroke length.

A mechanical approach to winding control. As an example of a mechanical system, a rolling ring traverse assembly is shown in Figure 4. The system, offers mechanically controlled, automatically reversing reciprocating motion with end stops that self-adjust outward to increase stroke length. Actuator traversing direction and pitch are controlled independently of the rotational direction and speed of the drive motor, thereby eliminating the need for clutches, gears and electronic controls. The shaft is threadless so the system does not require a protective shaft bellows assembly. Additionally, the design of the rolling ring bearing assures continuous point contact between the bearing and the drive shaft, thereby eliminating backlash.

Fig 4: A rolling ring winding assembly designed for winding onto a tapered flange spool. Fig. 5: Rolling ring drive reversal is mechanically controlled.

Reversal of a rolling ring actuator occurs when the spring-actuated reversal mechanism is triggered by contacting a hardware fixture called an "end stop" (Figure 5). The end stops in a rolling ring traversing assembly are positioned by the user to determine the actuator's stroke length. Reversal is mechanically controlled, independent of the drive motor operation.

The end stops in a rolling ring system may be positioned on moveable assemblies. The end stop assemblies can then be made to automatically move apart - through mechanical means - as the actuator traverses. This permits the required increase in stroke length when using a tapered flange spool.

Fig. 6: Illustration of a rolling ring system engineered for the winding of wire or cable onto a tapered flange spool. (See the text of the article for lettered references.)

As seen in Figure 6, the end stop assemblies (C) are mounted on two shafts called guide rails (D). The front most shaft is fitted with the end stop ratchet lever (E). A cam (G), affixed to the rolling ring drive (A), is positioned so the ratchet lever is actuated each time the drive passes by. When the lever is actuated, the front shaft rotates relative to an adjustable value, which is preset using the control knob (F). As the shaft turns, it bears against the bearings (H) mounted on the end stop assemblies. The bearings are pressed against the smooth shaft and function like a screw to move the end stop assemblies apart. As the end stops - which trigger the reversal mechanism (B) -- move apart, the required increase in stroke length is achieved. When the spool is filled, the assembly is reset by hand.

Once pitch is set in a rolling ring linear actuator, it remains constant regardless of stroke length, or rotational speed of the motor. This assures that the material is laid onto the spool at the proper rate per spool revolution. A tapered flange winding set-up may also be used for a standard cylindrical spool winding process by setting the stroke adjustment control to zero.