Device for detecting metal objects passing through an opening

• US 5,659,247 A
• Filed: 12/11/1995
• Issued: 08/19/1997
• Est. Priority Date: 03/10/1994
• Status: Expired due to Fees

• Current Assignee: Denver Dynamics, Inc.
• Original Assignee: Denver Dynamics, Inc.
• Inventors: Clements, Philip E.
• Primary Examiner(s): Strecker, Gerard R.
• Application Number:
  US08/570,348
• Time in Patent Office: 617 Days
• Field of Search: 324/202, 324/207.17, 324/207.26, 324/226, 324/227, 324/233-243, 324/262, 324/329, 235/449, 209/549, 209/562, 209/567, 209/570, 209/576-579, 209/926, 340/551, 340/568, 340/572, 340/941-943, 250/215, 250/561, 356/373, 356/375
• US Class Current: 324/239
• CPC Class Codes: A61B 50/30 Containers specially adapted for packaging, protecting, dispensing, collecting or disposing of surgical or diagnostic appliances or instruments for wound clamps A61B17/10; for ligaturing clips A61B17/122; packages or dispensers for surgical gloves or finger-stalls A61B42/40
• CPC Class Codes: B65F 1/1415 for flexible receptables, e.g. bags, sacks
• CPC Class Codes: B65F 2210/1525 for metal
• CPC Class Codes: G01V 3/15 specially adapted for use during transport, e.g. by a person, vehicle or boat

Abstract

A metal detection device is disclosed and includes a housing defining a central aperture. An induction member is mounted to the housing and surrounds the aperture for generating an output voltage in response to the presence of a metal object near the induction member. A mechanism is provided for calibrating the induction member by comparing the output voltage to a reference voltage to establish a threshold voltage which is unaffected by transient fluctuations in the output voltage. A mechanism is also provided in the housing and spaced about the aperture for selectively sensing an object passing through the aperture. The sensing mechanism generates a detection signal in response to passage of an object through the aperture only upon activation of the sensing mechanism. A mechanism activates the sensing mechanism upon generation of an inductive member output voltage above the threshold voltage. Finally, a device is provided for triggering an alarm in response to the generation of the detection signal.

Claims

1. A metal detection device comprising:

a housing defining a central aperture;

an induction member mounted to said housing and surrounding said aperture for generating an output voltage in response to the presence of a metal object near said induction member;

means for calibrating said induction member by comparing said output voltage to a reference voltage to establish a threshold voltage which is unaffected by transient environmental fluctuations in said output voltage;

means disposed in said housing and spaced about said aperture for selectively sensing an object passing through said aperture, said sensing means generating a detection signal in response to passage of an object through said aperture only upon activation of said sensing means;

means for activating said sensing means upon generation of an inductive member output voltage above said threshold voltage; and

means for triggering an alarm in response to the generation of said detection signal.

2. The device as claimed in claim 1, wherein said induction member comprises an electromagnetic detection coil.

3. The device as claimed in claim 1, wherein said object sensing means comprises pulse emission means positioned on one side of said aperture and pulse reception means positioned on an opposite side of said aperture for generating said detection signal.

4. The device as claimed in claim 3, wherein said pulse emission means comprises a plurality of infrared light emitting diodes, and said pulse reception means comprises a plurality of infrared phototransistors.

5. The device as claimed in claim 4, wherein said light emitting diodes and said phototransistors are spaced opposite each other in paired relationship to span the entire opening of said aperture.

6. The device as claimed in claim 3, wherein said pulse reception means generates said detection signal only upon failure of one or more of said pulse reception means to register emissions from a paired, activated pulse emission means, thereby indicating blockage of said pulse emission means by an object passing through said aperture.

7. The device as claimed in claim 1, wherein said means for activating said sensing moans comprises an electrical circuit for generating an electric pulse to said sensing means upon generation of an induction member output voltage in excess of said threshold voltage.

8. The device as claimed in claim 7, wherein said sensing means is activated less than 10 microseconds after generation of said threshold output voltage.

9. The device as claimed in claim 8, wherein said sensing means is activated for approximately 20 microseconds.

10. The device as claimed in claim 1, wherein said alarm comprises visual and audio alarms.

11. The device as claimed in claim 1, wherein said housing is sized and shaped to removably cover an open-ended receptacle wherein said aperture is aligned with the open end of said receptacle to detect the passing of metal objects into said receptacle through said aperture.

12. A metal detection device comprising:

a housing defining a central aperture;

a detection coil mounted to said housing and surrounding said aperture for generating an output voltage when a metal object is passed near said coil;

means for automatically calibrating said detection coil by comparing said output voltage to a reference voltage to establish a threshold voltage output which ignores transient environmental fluctuations in said coil output voltage;

a plurality of pulse emitting members spaced along a first side portion of said housing aperture;

a plurality of pulse reception members spaced along a second side portion of said housing aperture opposite said first side portion to receive and sense the output of said pulse emitting members upon activation thereof;

means for simultaneously activating said pulse emitting members upon generation of a coil output voltage above said threshold voltage; and

means for triggering a detection signal when at least one of said pulse reception members fails to register the output of one or more pulse emitting members upon simultaneous activation of said pulse emitting members.

13. The device as claimed in claim 12, wherein the output of said pulse emitting members comprises light or ultrasonic waves, with said pulse reception members receiving and registering the same.

14. The device as claimed in claim 13, wherein said pulse emitting members comprise infrared light emitting diodes, and said pulse reception members comprise infrared phototransistors.

15. The device as claimed in claim 13, wherein said pulse emitting members and pulse reception members are present in sufficient numbers to span the entire width of said aperture to detect any object passing through any portion of said aperture.

16. The device as claimed in claim 15, wherein said pulse emitting members and pulse reception members are aligned in pairs.

17. The device as claimed in claim 12, wherein said pulse emitting members are simultaneously activated within about 10 microseconds following the generation of said coil output voltage in excess of said threshold voltage output level.

18. The device as claimed in claim 17, wherein said pulse emitting members are activated for approximately 20 microseconds, the nonregistration of the output of at least one pulse emitting member at one said pulse reception member indicating the physical presence of a metal object passing through said aperture.

19. The device as claimed in claim 12, wherein said housing is sized and shaped to removably cover an open-ended receptacle wherein said aperture is aligned with the open end of said receptacle to detect the passing of metal objects into said receptacle through said aperture.

20. A device for detecting metal objects as they are inserted into a receptacle having an open upper end, said device comprising:

a housing sized and shaped to cover said receptacle open upper end, said housing defining a central aperture for access to said open upper end;

inductive means disposed within said housing surrounding said aperture for generating an output voltage when a metal object passes proximate thereto;

means for automatically calibrating said induction means by comparing said output voltage to a reference voltage to provide a threshold voltage which is unaffected by transient environmentally induced fluctuations in said output voltage;

means disposed in said housing and spaced about said aperture for selectively sensing the presence of an object passing through said aperture, said sensing means generating an electric signal in response thereto upon activation of said sensing means;

means for activating said sensing means upon generation of an inductive means output voltage above said threshold voltage; and

means for triggering an alarm detection signal in response to generation of said sensing means electric signal.

21. The device as claimed in claim 20, wherein said housing includes means for mounting said housing to said receptacle between an open position allowing access to said receptacle and a closed position for substantially covering said receptacle open upper end except through said aperture.

22. The device as claimed in claim 20, wherein said inductive moans comprises an electromagnetic detection coil.

23. The device as claimed in claim 22, wherein said sensing means comprises a plurality of pulse emission members positioned along one side portion of said aperture and a plurality of pulse reception members positioned on the opposite side portion of said aperture to scan the entire width of said aperture.

24. The device as claimed in claim 23, wherein said pulse emission members comprise infrared light emitting diodes and said pulse reception members comprise infrared phototransistors.

25. The device as claimed in claim 22, wherein said signal triggering means is adapted to activate upon failure of at least one said pulse reception member to detect emissions from at least one said pulse emission member upon activation thereof thereby indicating the physical presence of an object in said aperture blocking the pulse emissions.