Muffler assembly for a bagless vacuum cleaner

1. A muffler assembly for a vacuum cleaner, comprising:

a housing;

a dirt cup removably secured to the housing and having an exit;

a motor/fan unit fluidly connected to the dirt cup exit; and

an expansion chamber positioned downstream of the motor/fan unit and defined at least partially by the housing and a vertical wall of the dirt cup when the dirt cup is in an operational position relative to the housing; wherein:

the motor/fan units draws air from the dirt cup exit, and

the motor/fan unit directs an air stream toward the expansion chamber.

2. The muffler assembly of claim 1 , further comprising:

a fan duct extending from the dirt cup exit to an inlet of the motor/fan unit, wherein the fan duct extends substantially the entire length of the dirt cup.

3. The muffler assembly of claim 2 , the dirt cup assembly further comprising a lid, wherein:

the dirt cup exit is defined in the lid.

4. The muffler assembly of claim 3 , the lid further comprising a filter which covers the dirt cup exit.

5. The muffler assembly of claim 4 , the lid further comprising a screen.

6. The muffler assembly of claim 1 , the dirt cup further comprising a number of lateral extensions,

wherein an expansion chamber exit is defined the housing and the lateral extensions.

7. The muffler assembly of claim 1 , further comprising a number of vanes, wherein:

the vanes direct the airflow in an expansion chamber exit.

8. The muffler assembly of claim 7 , wherein the vanes direct the air flow in the expansion chamber exit in an upward direction.

9. The muffler assembly of claim 1 , further comprising:

a fan exhaust duct which directs air from the motor/fan unit to the expansion chamber; and

a final filter positioned between the fan exhaust duct and the expansion chamber.

10. The muffler assembly of claim 9 , wherein the final filter is substantially parallel to a side wall of the dirt cup when the dirt cup is in the operational position.

11. An upright vacuum cleaner, comprising:

a carpet engaging nozzle base;

an upper housing pivotally connected to the nozzle base;

a dirt cup removably secured to the upper housing and having an inlet in fluid communication with the nozzle base and an exit;

a motor/fan unit fluidly connected to the dirt cup exit and positioned proximate to a pivot axis between the base and the upper housing; and

an expansion chamber positioned downstream of the motor/fan unit and defined at least partially by the upper housing and a vertical wall of the dirt cup when the dirt cup is in an operational position relative to the housing; wherein:

the motor/fan units draws air from the dirt cup exit and directs air toward the expansion chamber.

12. The muffler assembly of claim 11 , further comprising:

a fan duct extending from the dirt cup exit to an inlet of the motor/fan unit, wherein the fan duct extends a substantial portion of the length of the upper housing.

13. The muffler assembly of claim 12 , the dirt cup assembly further comprising a lid, wherein the dirt cup exit is defined in the lid.

14. The muffler assembly of claim 13 , the lid further comprising a filter, wherein:

the filter covers the dirt cup exit, and

the filter separates particles advanced from the nozzle base.

15. The muffler assembly of claim 14 , the lid further comprising a screen in fluid communication with the nozzle base and the motor/fan unit.

16. The muffler assembly of claim 15 , the dirt cup further comprising a number of lateral extensions,

wherein an expansion chamber exit is defined by the housing and the lateral extensions.

17. The muffler assembly of claim 11 , further comprising a number of vanes, wherein:

the vanes direct the airflow in an expansion chamber exit.

18. The muffler assembly of claim 17 , wherein the vanes direct the air flow in the expansion chamber exit away from the carpet engaging nozzle base.

19. The muffler assembly of claim 11 , further comprising:

a fan exhaust duct which directs air from the motor/fan unit to the expansion chamber; and

a final filter positioned in the upper housing between the fan exhaust duct and the expansion chamber.

20. The muffler assembly of claim 19 , wherein the final filter is substantially parallel to a side wall of the dirt cup when the dirt cup is in the operational position.

21. A method of operating a vacuum cleaner, comprising the steps of:

positioning a removable dirt cup relative to the housing of the vacuum cleaner so as to define an expansion chamber between a vertical wall of the dirt cup and the housing;

directing an airflow from said dirt cup to the expansion chamber positioned downstream of a motor/fan unit with the motor/fan unit; and

muffling the sound of the airflow in the expansion chamber.

22. The method of claim 21 , further comprising the steps of:

ducting the airflow from the dirt cup exit to an inlet of the motor/fan unit along substantially the entire length of the dirt cup.

23. The method of claim 21 , further comprising the step of filtering the air stream in the dirt cup.

24. The method of claim 23 , further comprising the step of sieving the airflow in the dirt cup with a screen.

25. The method of claim 21 , further comprising the step of defining a expansion chamber exit with a number of lateral extensions on the dirt cup.

26. The method of claim 25 , further comprising the step of directing the airflow in the expansion chamber exit with the number of vanes.

27. The method of claim 26 , wherein the directing step includes the step of directing the air flow in an upward direction.

28. The method of claim 21 , further comprising the step of filtering the airflow prior to entering the expansion chamber with a final filter.