Fluid container sensor

• US 6,528,739 B1
• Filed: 08/29/2000
• Issued: 03/04/2003
• Est. Priority Date: 10/10/1997
• Status: Expired due to Fees

• Current Assignee: Northgate Technologies Incorporated
• Original Assignee: Northgate Technologies Incorporated
• Inventors: Cho, David, Jacobs, Raymond, Zander, Charles, Nowosielski, Albert, Kuzelka, Russell
• Primary Examiner(s): Gibson, Randy W.
• Application Number:
  US09/650,067
• Time in Patent Office: 917 Days
• Field of Search: 177/45, 177/46, 177/47, 177/48, 177/49, 177/225, 177/232, 177/245, 600/580, 600/581
• US Class Current: 177/45
• CPC Class Codes: G01G 17/04 for weighing fluids, e.g. gases, pastes
• CPC Class Codes: G01G 19/14 for weighing suspended loads G01G3/00 takes precedence; incorporation of weighing devices in cranes B66C1/40, B66C13/16

Abstract

A fluid sensor apparatus for monitoring fluid in a container. The fluid sensor apparatus comprises a housing having an upper hook extending from a top thereof to allow the housing to be suspended. A lower hook is telescopically received in the housing and extends from a bottom thereof. The lower hook is adapted for suspending a fluid container therefrom. The lower hook is movable relative to the housing. A cam member is located inside the housing and is movable relative thereto. The cam member is coupled to an upper end of the lower hook. The cam member has a stepped gradation. A biasing member is coupled between a lower shoulder of the cam member and the housing. The biasing member is adapted to apply a force against the cam member to cause the cam member to be biased upward relative to the housing to an upper position. A switch is coupled to the housing and has an actuator located in relation to the stepped gradation of the cam member. The switch is in a first state when the cam member is in the upper position. The switch is in a second state when a load suspended from the lower hook overcomes the force of the biasing member causing the cam member to be moved to a lower position relative to the housing. An alarm coupled to the switch is operative to indicate a fluid condition when the switch is in one of the first and second states.

Claims

1. A sensor for medical monitoring of a fluid in a container coupled to a patient, the sensor comprising:

an upper hook;

a lowerhook coupled to the upper hook and movable in relation thereto, along a first direction, said loser hook adapted for suspending a fluid container therefrom;

a cam member fixedly coupled to one of said hooks and movable in relation to the other of said hooks;

a biasing member coupled between said hooks;

a first switch coupled adjacent said cam member, wherein said first switch is biased in a second direction not parallel to said first direction so that said first switch bears against said cam member causing said first switch to be in a first state when said lower hook is unloaded and to be in a second state when said lower hook is sufficiently loaded to overcome said biasing member; and

an alarm coupled to said first switch and operative to indicate a fluid condition when said switch is in one of said states but not the other.

2. The invention of claim 1 wherein said alarm is an audible alarm.

3. The invention of claim 1 wherein said alarm is a visual alarm.

4. The invention of claim 1 further comprising a battery electrically coupled to said alarm and said first switch.

5. The invention of claim 1 further comprising an on/off switch in series with said first switch.

6. The invention of claim 1 wherein said first switch includes a leaf arm that bears on said cam member when said first switch is in one of said states but does not bear on said cam member when in the other of said states.

8. The invention of claim 1 wherein said alarm comprises an audible alarm and a visual alarm.

17. The invention of claim 1, wherein said cam member does not form a portion of an electrical path that causes said first switch to be in either said first state or said second state.

18. The invention of claim 1, wherein said first switch bears against a surface of said cam member that is parallel to said first direction.

19. The invention of claim 17, wherein said first switch bears against a surface of said cam member that is parallel to said first direction.

7. A sensor for medical monitoring of a fluid in a container coupled to a patient, the sensor comprising:

an upper hook;

a lower hook coupled to the upper hook and movable in relation thereto said lower hook adapted for suspending a fluid container therefrom;

a cam member fixedly coupled to one of said hooks and movable in relation to the other of said hooks;

a biasing member coupled between said hooks;

a first switch coupled adjacent said cam member and bearing thereagainst to cause said first switch to be in a first state when said lower hook is unloaded and to be in a second state when said lower hook is sufficiently loaded to overcome said biasing member;

wherein said first switch comprises a leaf arm;

a roller rotatably mounted on an end of said leaf arm, said roller bearing on said cam member; and

an alarm coupled to said first switch and operative to indicate a fluid condition when said switch is in one of said states but not the other.

20. The invention of claim 7, wherein said cam member does not form a portion of an electrical path that causes said first switch to be in either said first state or said second state.

21. The invention of claim 7, wherein said roller bears against a surface of said cam member that is parallel to said first direction.

22. The invention of claim 20, wherein said roller bears against a surface of said cam member that is parallel to said first direction.

9. A medical fluid sensor for monitoring weight of a fluid in a container, comprising:

a housing;

an upper hook coupled to said housing adapted for suspending said housing therefrom;

a lower hook telescopically received in said housing and extending from a bottom thereof, said lower hook adapted for suspending a fluid container therefrom, said lower hook movable relative to said housing;

a cam member located inside said housing and movable relative thereto, said cam member coupled to an upper end of said lower hook, and said cam member having a stepped gradation;

a biasing member coupled between a lower shoulder of said cam member and a shoulder coupled to said housing, said biasing member adapted apply a force against said lower shoulder of said cam member to cause said cam member to be biased upward along a first direction relative to said housing to an upper position relative thereto;

a first switch coupled to said housing and having a switch actuator located in relation to said stepped gradation on said cam member, wherein said switch actuator is biased in a second direction not parallel to said first direction causing said switch to be in a first state when said cam member is in said upper position and to be in a second state when a load suspended from said lower hook overcomes said force of said biasing member causing said cam member to be moved to a lower position relative to said housing; and

an alarm coupled to said switch operative to indicate a fluid condition when said first switch is in one of said states and not the other.

10. The invention of claim 9 wherein said alarm is an audible alarm.

11. The invention of claim 9 wherein said alarm is a visual alarm.

12. The invention of claim 9 further comprising a battery electrically coupled to said alarm and said first switch.

13. The invention of claim 9 further comprising an on/off switch in series with said first switch.

23. The invention of claim 9, wherein said cam member does not form a portion of an electrical path that causes said first switch to be in either said first state or said second state.

24. The invention of claim 9, wherein said switch actuator bears against a surface of said cam member that is parallel to said first direction.

25. The invention of claim 23, wherein said switch actuator bears against a surface of said cam member that is parallel to said first direction.

26. The invention of claim 9, wherein said cam member does not form a portion of an electrical path that causes said first switch to be in either said first state of said second state.

27. The invention of claim 9, wherein said roller bears against a surface of said cam member that is parallel to said first direction.

28. The invention of claim 26, wherein said roller bears against a surface of said cam member that is parallel to said first direction.

31. The invention of claim 28, wherein said actuator bears against a surface of said cam member that is parallel to said first direction.

14. A self-contained battery-operated fluid sensor for monitoring weight of a fluid in a container, comprising:

a housing;

an upper hook extending from a top of said housing;

a lower hook received in said housing and extending from a bottom thereof, said lower hook adapted for suspending a fluid supply therefrom, said lower hook being movable vertically relative to said housing;

a cam member located inside said housing and coupled to an upper end of said lower hook, said cam member being movable with said lower hook relative to said housing, thereto, and said cam member having a stepped gradation;

a biasing member coupled between a lower shoulder of said cam member and a shoulder coupled to said housing, said biasing member adapted to apply a force against said lower shoulder of said cam member to cause said cam member to be biased upward along a first direction relative to said housing to an upper position relative thereto;

a first switch coupled to said housing and having an actuator located in relation to said stepped gradation on said cam member, wherein said actuator is biased in a second direction not parallel to said first direction causing said first switch to be in a first state when said cam member is in said upper position and to be in a second state when a load suspended from said lower hook overcomes said force of said biasing member causing said cam member to be moved to a lower position relative to said housing;

a battery electrically coupled to said first switch; and

an alarm coupled said first switch to receive power from said battery upon operation of said first switch to indicate a fluid condition when said first switch is in one of said first and second states.

15. The invention of claim 14 wherein said fluid condition is a low fluid condition.

16. the invention of claim 14 wherein said fluid condition is a high fluid condition.

29. The invention of claim 14, wherein said cam member does not form a portion of an electrical path that causes said first switch to be in either said first state or said second state.

30. The invention of claim 14, wherein said actuator bears against a surface of said cam member that is parallel to said first direction.