High torque resistant and strong screwless plastic gear box

• US 6,857,338 B2
• Filed: 08/19/2002
• Issued: 02/22/2005
• Est. Priority Date: 08/19/2002
• Status: Active Grant

• Current Assignee: Molon Motor and Coil Corporation
• Original Assignee: Molon Motor and Coil Corporation
• Inventors: Tsergas, Athanase N.
• Primary Examiner(s): FENSTERMACHER, DAVID MORGAN
• Application Number:
  US10/222,886
• Publication Number:
  US 20040031343A1
• Time in Patent Office: 918 Days
• Field of Search: 744/14, 746/06.R, 744/13, 744/12.R, 744/21.A
• US Class Current: 74/606.00R
• CPC Class Codes: F16H 2057/02095 Measures for reducing number of parts or components
• CPC Class Codes: F16H 57/028 characterised by means for reducing vibration or noise
• CPC Class Codes: F16H 57/032 characterised by the materials used
• CPC Class Codes: Y10T 74/19651 External type
• CPC Class Codes: Y10T 74/19684 Motor and gearing
• CPC Class Codes: Y10T 74/2186 Gear casings

Abstract

A high torque resistant and strong screwless plastic gear box has a reduced thickness at its output shaft. The gear box and a reduction drive assembly therein may be used particularly, but not exclusively, in a slot machine with a spinning drum or hopper which holds coins or tokens to be released therefrom. The gear box includes a main body and a cover which is ultrasonically welded thereto. Locating posts, holding tubes, inner welding pads, outer surrounding tubes, and locating ribs are provided to weld the cover to the main body. Acoustical chambers are formed between outer walls and inner arcuate walls of the main body. The inner arcuate walls surround all of the shafts and gears inside the main body. This double-walled construction reduces noise and provides surprising mechanical strength. All of the gears are mounted on only three shafts secured between the main body and the cover. Four of the gears are stacked on a single central shaft and rotate in two pairs independently of each other.

Claims

1. A screwless gear box comprising:

a. a main body having a first raised boss, a second raised boss and a first collar;

b. a cover ultrasonically sealed onto the main body, said cover having a first raised boss, a second raised boss and a second collar;

c. a central shaft being held at one end in the first raised boss of the main body and being held at an opposite end in the first raised boss of the cover;

d. a second shaft being held at one end in the second raised boss of the main body and being held at an opposite end in the second raised boss of the cover; and

e. an output shaft being held at its midsection by the first collar of the main body and being held at a nonworking end by the second collar of the cover.

2. A gear box, according to claim 1, further comprising:

a coupling being held at a working end of the output shaft.

3. A gear box, according to claim 1, further comprising:

a first central gear mounted on the central shaft.

4. A gear box, according to claim 3, further comprising:

a first pinion gear carried by the first central gear.

5. A gear box, according to claim 4, further comprising:

a second gear being mounted on the second shaft and being driven by the first pinion gear.

6. A gear box, according to claim 5, further comprising:

a second pinion gear being carried by the second gear and abutting against the second raised boss of the main body.

7. A gear box, according to claim 6, further comprising:

a third gear mounted on the central shaft and abutted by the first pinion gear, said third gear being driven by the second pinion gear and rotating independently of the first central gear and the first pinion gear on the central shaft.

8. A gear box, according to claim 7, further comprising:

a third pinion gear being carried by the third gear and abutting against the first raised boss of the main body.

9. A gear box according to claim 8, further comprising:

an output gear being carried by the output shaft and being driven by the third pinion gear, said output gear being retained on the output shaft at one side by the first collar of the main body and being retained on the output shaft at an opposite side by the second collar of the cover.

10. A gear box, according to claim 9, further comprising:

a plurality of inner arcuate wall sections formed in the main body so that an enclosed space is formed surrounding all of the shaft and the gears.

11. A gear box, according to claim 1, further comprising:

a mounting pad being formed integrally on the cover and having a first pair of arms and a second pair of arms.

12. A gear box, according to claim 11, further comprising:

a direct current motor being secured on the cover through the first pair of arms of the mounting pad and being balanced on the cover by the second pair of arms of the mounting pad so that there is no wobble of the direct current motor during operation.

13. A gear box, according to claim 12, further comprising:

an input shaft turned by the direct current motor.

14. A gear box, according to claim 13, further comprising:

an input gear carried and rotated by the input shaft.

15. A gear box, according to claim 3, further comprising:

an input gear configured to drive the first central gear.

16. A gear box according to claim 1, further comprising:

a plurality of fasteners placed in holes positioned on the main body symmetrically and equidistantly from the output shaft.

17. A gear box, according to claim 1, further comprising:

a plurality of locating posts formed on an inner side of the cover.

18. A gear box, according to claim 17, further comprising:

a plurality of hollow holding tubes being formed on the main body and corresponding in position to the plurality of locating posts so that each locating post projects into a corresponding tube.

19. A gear box, according to claim 1, further comprising:

a plurality of welding rings being formed on an inner side of the cover.

20. A gear box, according to claim 19, further comprising:

a plurality of inner welding pads and outer surrounding tubes being formed on the main body and corresponding in position to the plurality of welding rings so that each welding ring fits into a space between the inner welding pad and the outer surrounding tube corresponding thereto.

21. A gear box, according to claim 1, further comprising:

a plurality of locating ribs being formed on an inner side of the cover.

22. A gear box, according to claim 21, further comprising:

a plurality of acoustical chambers being formed in the main body and corresponding in position to the plurality of locating ribs so that each locating rib snaps into the acoustical chamber corresponding thereto.

23. A gear box, according to claim 2, wherein:

said coupling is a solid pin.