Method of forming raceway knockout

1. A method for forming a knockout on a raceway, the method comprising:

removing a portion of material from the raceway by completely separating the portion from the raceway to form an opening in the raceway;

positioning the portion within the opening; and

thereafter attaching the portion to the raceway by welding the portion and the raceway together to form the knockout.

2. The method of claim 1 , wherein positioning the portion includes positioning the edges of the portion directly adjacent and abutting the edges of the raceway opening to form a seam between the portion and the raceway, and attaching the portion to the raceway includes welding the portion and the raceway along the seam.

3. The method of claim 2 , further comprising, after attaching the portion to the raceway, breaking the knockout away from the raceway.

4. The method of claim 3 , wherein breaking the knockout away from the raceway includes applying pressure to the knockout to cause the knockout to generally separate from the raceway along the seam.

5. The method of claim 1 , wherein the portion and the raceway are both formed from a plastic material.

6. The method of claim 1 , wherein attaching the portion to the raceway includes welding the portion to the raceway by an ultrasonic welding process.

7. The method of claim 1 , wherein attaching the portion to the raceway includes positioning a welding horn adjacent the portion and the raceway, the welding horn having a welding surface that is substantially aligned with a seam between the portion and the raceway.

8. The method of claim 7 , wherein the welding surface has a shape substantially corresponding to a shape of the seam.

9. The method of claim 7 , wherein the welding horn includes a plurality of energy directors positioned on the welding surface, each energy director including a truncated pyramid having a recessed peak.

10. The method of claim 9 , wherein positioning the welding surface adjacent the portion and the raceway includes positioning at least some of the energy directors to span across the seam and form a weld therein, the plurality of energy directors being arranged such that the distance between adjacent welds along the seam is less than a predetermined maximum length.

11. The method of claim 7 , wherein positioning the portion within the opening includes aligning a surface of the raceway to which the welding horn is applied with a surface of the portion to which the welding horn is applied so that the surfaces are substantially coplanar.

12. A method for joining a first plastic workpiece and second plastic workpiece, the method comprising:

positioning an edge of the first workpiece adjacent an edge of the second workpiece so that the edges engage one another in a facing relationship;

positioning a welding horn adjacent the first workpiece and the second workpiece, positioning the welding horn including aligning the welding surface with a seam defined by the edges of the first workpiece and the second workpiece, a welding surface of the welding horn being in contact with both the first workpiece and the second workpiece, the welding surface including a plurality of energy directors, each energy director including a truncated pyramid having a recessed peak; and

welding the edges of the first and second workpieces together by an ultrasonic welding process.

13. The method of claim 12 , wherein the welding surface has a shape substantially corresponding to a shape of the seam.

14. The method of claim 12 , wherein positioning the welding horn includes positioning at least some of the energy directors to span across the seam, wherein welding the edges includes forming welds across the seam by the energy directors that span across the seam, the distance between adjacent welds along the seam being less than a predetermined maximum length.

15. The method of claim 12 , wherein positioning the edge of the first workpiece adjacent the edge of the second workpiece includes aligning a surface of the raceway to which the welding horn is applied with a surface of a knockout to which the welding horn is applied so that the surfaces are substantially coplanar.

16. A method for forming a knockout on a raceway, the method comprising:

removing a portion of material from the raceway to form an opening;

positioning the portion within the opening; and

thereafter attaching the portion to the raceway by welding the portion and the raceway together to form the knockout, welding the portion including positioning a welding horn adjacent the portion and the raceway, the welding horn including a welding surface that is substantially aligned with a seam between the portion and the raceway, the welding horn further including a plurality of energy directors positioned on the welding surface, each energy director including a truncated pyramid having a recessed peak.

17. The method of claim 16 , wherein positioning the portion includes positioning the edges of the portion directly adjacent and abutting the edges of the opening of the raceway to form a seam between the portion and the raceway, and attaching the portion to the raceway includes welding the portion and the raceway along the seam.

18. The method of claim 17 , further comprising, after attaching the portion to the raceway, breaking the knockout away from the raceway.

19. The method of claim 18 , wherein breaking the knockout away from the raceway includes applying pressure to the knockout to cause the knockout to generally separate from the raceway along the seam.

20. The method of claim 16 , wherein the portion and the raceway are both formed from a plastic material, and wherein welding the portion and the raceway together refers to an ultrasonic welding process.

21. The method of claim 16 , wherein the welding surface has a shape substantially corresponding to a shape of the seam.

22. The method of claim 16 , wherein positioning the welding surface adjacent the portion and the raceway includes positioning at least some of the energy directors to span across the seam and form a weld therein, the plurality of energy directors being arranged such that the distance between adjacent welds along the seam is less than a predetermined maximum length.

23. The method of claim 16 , wherein positioning the portion within the opening includes aligning a surface of the raceway to which the welding horn is applied with a surface of the portion to which the welding horn is applied so that the surfaces are substantially coplanar.

24. The method of claim 8 , wherein the seam forms a closed shape.