Shredder with jam proof system

• US 8,091,809 B2
• Filed: 03/24/2009
• Issued: 01/10/2012
• Est. Priority Date: 03/24/2009
• Status: Active Grant

• Current Assignee: Fellowes Incorporated
• Original Assignee: Fellowes Incorporated
• Inventors: Hu, Jin, Cai, Qingcheng, Huang, Aiyu, Jensen, Michael D
• Primary Examiner(s): Francis, Faye
• Application Number:
  US12/409,896
• Publication Number:
  US 20100243774A1
• Time in Patent Office: 1,022 Days
• Field of Search: 241/30, 241/34, 241/36, 241/100, 241/236
• US Class Current: 241/30
• CPC Class Codes: B02C 18/0007 specially adapted for disintegrating documents
• CPC Class Codes: B02C 18/16 Details
• CPC Class Codes: B02C 2018/0015 for disintegrating CDs, DVDs and/or credit cards
• CPC Class Codes: B02C 2018/164 Prevention of jamming and/or overload
• CPC Class Codes: B02C 23/04 Safety devices in general F16P ; for rotary mills B02C13/31
• CPC Class Codes: B02C 25/00 Control arrangements specially adapted for crushing or disintegrating

Abstract

A shredder is disclosed having a jam proof system. In one embodiment, the jam proof system provides a thickness detector having a contact member which displaces as an article is inserted into a throat of the shredder and a resistance generating mechanism configured to provide a resistance force to the contact member, in response to displacement of the contact member. The greater the thickness of the material the greater the resistance force that will be realized. When the material reaches a predetermined thickness, there will be a significant change in the resistance force. The resistance generating mechanism may include at least two spring mechanisms serially arranged, such as, a first spring mechanism and a second spring mechanism. This feature provides immediate and direct feedback to the user that the article inserted into the shredder may be too thick. In addition, the thickness detector may include a sensor, and in particular, a Hall effect sensor assembly configured to measure the thickness of the article inserted into the throat. The sensor may communicate with a controller that is configured to alert the user, and/or alter the operation of the shredder, in response to the thickness of the material. For example, the controller may visually and/or audibly alert the user, or control the shredder motor response.

Claims

1. A shredder comprising:

a housing having a throat for receiving at least one article to be shredded;

a shredder mechanism positioned downstream of the throat in the direction that the articles are fed; and

a contact member that is configured to displace as the article passes through the throat; and

a resistance generating mechanism for resisting displacement of the contact member, the resistance generating mechanism comprising;

(i) a first spring configured to resist displacement of the contact member at least up to a predetermined displacement; and

(ii) a second spring configured to resist displacement of the contact member beyond the predetermined displacement,

wherein the first and second springs are configured such that the ratio of force to displacement is lower below the predetermined displacement and greater beyond the predetermined displacement.

2. The shredder according to claim 1, further comprising:

a sensor associated with the contact member and configured to measure the thickness of articles fed into the throat.

3. The shredder according to claim 1, wherein the second resistance is a combination of the first and second resistance forces.

4. The shredder according to claim 1, wherein each of the first and second springs is one of a torsion spring or a liner spring.

5. The shredder according to claim 1, wherein one of the first and second springs is a torsion spring and the other of the first and second springs is a linear spring.

6. The shredder according to claim 1, wherein the contact member comprises a cam mechanism having a surface which contacts the article.

7. The shredder according to claim 6, wherein the contact member further comprises an arm extending away from the cam mechanism.

8. The shredder according to claim 2, wherein the sensor is a Hall effect sensor or a capacitance sensor.

9. The shredder according to claim 8, where the hall-effect sensor comprises at least one NdFeN permanent magnet.

10. The shredder according to claim 8, wherein the hall-effect sensor comprises two magnets spaced apart.

11. The shredder according to claim 1, wherein the throat include a side opening permitting the contact member to displace therethrough.

12. The shredder according to claim 1, one or both of the first and second spring comprise:

an elastomer member, weight, fluid or gap damper, linear spring, torsion spring, or leaf spring.

13. A method of shredding comprising:

inserting an article to be shredded into a housing having a throat for receiving articles to be shredded;

displacing a contact member positioned in the throat, wherein the displacement corresponds to the thickness of the article in the throat;

generating a resistance as the contact member displaces, said generating comprising;

(i) providing a first resistance configured to resist displacement of the contact member at least up to a predetermined displacement; and

(ii) providing a second resistance configured to resist displacement of the contact member beyond the predetermined displacement,

wherein the first and second resistances are configured such that the ratio of force to displacement is lower below the predetermined displacement and greater beyond the predetermined displacement.

14. The method according to claim 13, further comprising:

measuring, with a sensor, the thickness of articles fed into the throat.

15. The method according to claim 13, wherein the second resistance is a combination of first and second resistances.

16. The method according to claim 13, wherein each of the first and second resistances is generated using one of a torsion spring or a liner spring.

17. The method according to claim 13, wherein one of the first and second resistances is generated using a torsion spring and the other of the first and second resistances is generated using a linear spring.

18. The method according to claim 13, wherein the contact member comprises a cam mechanism having a surface which contacts the article.

19. The shredder according to claim 13, further comprising:

providing an alert in response to the sensor measuring the thickness of the said articles.

20. The method according to claim 13, further comprising:

altering the shredding in response to the sensor measuring the thickness of the said articles.

21. The method according to claim 20, wherein the altering comprises:

adjusting the speed, torque or power of the shredding.

22. The method according to claim 20, wherein the altering comprises:

deactivating the shredding.

23. The method according to claim 13, wherein providing one or both of the first and second resistance forces comprise providing a spring.

24. The method according to claim 23, wherein the spring comprises:

an elastomer member, weight, fluid or gap damper, linear spring, torsion spring, or leaf spring.