Liquid level gauge

• US 6,041,650 A
• Filed: 08/26/1997
• Issued: 03/28/2000
• Est. Priority Date: 08/26/1997
• Status: Expired due to Term

• Current Assignee: Rochester Gauges Incorporated
• Original Assignee: Rochester Gauges Incorporated
• Inventors: Dudley, Amber N., Swindler, Danny E., Ross, Herbert G. Jr.
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): WORTH, WILLIE M
• Application Number:
  US08/918,951
• Time in Patent Office: 945 Days
• Field of Search: 73/305, 73/317, 73/DIG. 5, 116/229
• US Class Current: 73/317
• CPC Class Codes: F17C 2250/0413 with floats
• CPC Class Codes: G01F 23/34 using mechanically actuated indicating means G01F23/38 takes precedence
• CPC Class Codes: G01F 23/38 using magnetically actuated indicating means
• CPC Class Codes: Y10S 73/05 Liquid levels with magnetic transmission

Abstract

A float-type liquid level gauge is provided for measuring the level within a tank of liquids such as liquified petroleum gases. The liquid level gauge includes a movable float arm (30) coupled by gears (46, 48) to a magnet shaft (26) and magnet (28) mounted in a rigid support arm (24) through a side-accessible shaft passage (110). The support arm is connected to the lower side of a gauge head (22) and the magnet extends into a passage (52) in the gauge head so as to be magnetically coupled to a level indicating dial (34) provided on the upper side of the gauge head.

Claims

1. A liquid level gauge comprising:

a) a gauge head having a lower portion defining a passage formed on its lower surface and a dial assembly mounting portion formed on its upper surface;

b) a support arm having an upper end connected to said lower portion of said gauge head, a float arm attachment portion being located at a distance from said upper end, and a middle portion extending between said upper end and said float arm attachment portion;

said middle portion defining a side-accessible shaft passage extending between said upper end and said float arm attachment portion;

c) a magnet drive shaft rotatably mounted in said shaft passage and having a magnet holder located at an upper end and a shaft gear located at a distance from said upper end;

said upper end of said shaft extending beyond said upper end of said support arm and positioning said magnet holder within said passage of said gauge head;

d) a magnet being secured to said magnet holder of said magnet drive shaft;

e) a float arm having a first portion being pivotally connected to said float arm attachment portion of said support arm, having a float arm gear located on said first portion, and having a float attachment member being formed at a distance from said first portion;

said float arm gear engaging said shaft gear to impart rotational motion to said shaft, said magnet holder and said magnet relative to said support arm and said gauge head upon rotation of said float arm relative to said support arm;

f) a float being attached to said float attachment member of said float arm;

g) said support arm further comprising at least one shaft retainer;

each said shaft retainer having opposing members formed integrally with said middle portion of said support arm to define a gap between said opposing members;

said gap having a width thereacross when no force is applied against said opposing members which is less than the diameter of the portion of the magnet drive shaft adjacent said opposing members; and

h) an indicating dial assembly mounted on said gauge head, said dial assembly including a receiving magnet rotatably mounted within a non-magnetic shell and connected to a visible pointer.

2. A liquid level gauge according to claim 1, further comprising an internal float stop having a first portion formed integrally with said float arm and having a second portion formed integrally with said support arm.

3. A liquid level gauge according to claim 2, wherein said second portion of said internal float stop comprises a keyway formed on said support arm and said first portion of said internal float stop comprises a key formed on said float arm, both of said key and keyway being completely covered by a portion of said float arm, said key interfitting within said keyway to define a range of angular motion for said float arm with respect to said support arm.

4. A liquid level gauge according to claim 1, wherein said magnet drive shaft is molded as part of a single piece including said magnet holder and said shaft gear.

5. A liquid level gauge according to claim 4, wherein said magnet drive shaft is formed of acetal plastic.

6. A liquid level gauge according to claim 1, wherein said support arm is molded as a single piece.

7. A liquid level gauge according to claim 6, wherein said support arm further comprises an integral head support member disposed within said passage of said head.

8. A liquid level gauge according to claim 1, wherein said float arm is molded as part of a single piece including said float gear.

9. A liquid level gauge according to claim 8, wherein said float arm is formed of acetal plastic.

10. A liquid level gauge according to claim 2, wherein said second portion of said internal float stop comprises a key formed on said support arm and said first portion of said internal float stop comprises a keyway formed on said float arm, both of said key and keyway being completely covered by a portion of said float arm, said key interfitting within said keyway to define a range of angular motion for said float arm with respect to said support arm.

11. A liquid level gauge comprising:

a) a gauge head having a lower portion defining a passage formed on its lower surface and a dial assembly mounting portion formed on its upper surface;

b) a support arm having an upper end connected to said lower portion of said gauge head, a float arm attachment portion being located at a distance from said upper end, and a middle portion extending between said upper end and said float arm attachment portion;

said middle portion defining a side-accessible shaft passage extending between said upper end and said float arm attachment portion;

c) a magnet drive shaft rotatably mounted in said shaft passage and having a magnet holder located at an upper end and a shaft gear located at a distance from said upper end;

said upper end of said shaft extending beyond said upper end of said support arm and positioning said magnet holder within said passage of said gauge head;

d) a magnet being secured to said magnet holder of said magnet drive shaft;

e) a float arm having a first portion being pivotally connected to said float arm attachment portion of said support arm, having a float arm gear located on said first portion, and having a float attachment member being formed at a distance from said first portion;

said float arm gear engaging said shaft gear to impart rotational motion to said shaft, said magnet holder and said magnet relative to said support arm and said gauge head upon rotation of said float arm relative to said support arm;

f) a float being attached to said float attachment member of said float arm;

g) said magnet holder of said magnet drive shaft further comprising a resilient member which is deformed during insertion of said magnet into said magnet holder and which thereafter biases said magnet against said magnet holder, thereby securing said magnet to said magnet holder; and

h) an indicating dial assembly mounted on said gauge head, said dial assembly including a receiving magnet rotatably mounted within a non-magnetic shell and connected to a visible pointer.

12. A liquid level gauge according to claim 11, wherein said magnet has a flux field axis, and wherein insertion of said magnet into said magnet holder predictably aligns said flux field axis with respect to said magnet holder.

13. A liquid level gauge according to claim 11, further comprising an internal float stop having a first portion formed integrally with said float arm and having a second portion formed integrally with said support arm.

14. A liquid level gauge according to claim 13, wherein said second portion of said internal float stop comprises a keyway formed on said support arm and said first portion of said internal float stop comprises a key formed on said float arm, both of said key and keyway being completely covered by a portion of said float arm, said key interfitting within said keyway to define a range of angular motion for said float arm with respect to said support arm.

15. A liquid level gauge according to claim 13, wherein said second portion of said internal float stop comprises a key formed on said support arm and said first portion of said internal float stop comprises a keyway formed on said float arm, both of said key and keyway being completely covered by a portion of said float arm, said key interfitting within said keyway to define a range of angular motion for said float arm with respect to said support arm.

17. A liquid level gauge comprising a liquid level gauge sub-assembly according to claim 15 and a magnetically coupled indicator dial assembly mounted on said gauge head.

18. A liquid level gauge according to claim 17 wherein said support arm, said magnet drive shaft, and said float are formed of acetal plastic.

16. A liquid level gauge sub-assembly for use with a magnetically driven indicating dial assembly, said gauge sub-assembly comprising:

a) a gauge head having a lower portion defining a passage formed on its lower surface and a dial assembly receiving portion formed on its upper surface;

b) a one-piece support arm having an upper end connected to said lower portion of said gauge head, an integral float arm attachment portion being formed at a distance from said upper end, and a middle portion extending between said upper end and said float arm attachment portion;

said upper end including an integral head supporting member disposed within said passage of said gauge head;

said float arm attachment portion including one of an integral keyway and an integral key;

said middle portion defining a side-accessible shaft passage and at least one integral shaft retainer having opposing members projecting towards one another and defining a gap therebetween;

said gap having a first width thereacross when no force is applied against said retaining member;

c) a one-piece magnet drive shaft having an integral magnet holder formed at an upper end and an integral shaft gear formed at a distance from said upper end;

said shaft having, in regions proximate any said shaft retainer, a diameter greater than said first width of said gap between said opposing members of said shaft retainer;

said magnet holder being adapted to deform during insertion of a magnet into said magnet holder and thereafter biasing said magnet against said magnet holder to secure said magnet to said magnet holder;

said upper end of said magnet drive shaft extending beyond said upper end of said support arm and positioning said magnet holder within said tubular passage of said gauge head;

d) a magnet being secured to said magnet holder;

e) a one-piece float arm having a first portion pivotally connected to said float arm attachment portion of said support arm;

said float arm having the other of said keyway and said key formed thereon, having an integral pivot gear formed thereon, and having an integral float attachment portion formed at a distance from said first portion;

said key being cooperatively positioned within said keyway to define a range of angular motion for said float arm with respect to said support arm;

said pivot gear engaging said shaft gear to impart rotational motion to said shaft, said magnet holder, and said magnet relative to said support arm and said head upon rotation of said float arm relative to said support arm; and

f) a float attached to said float attachment portion of said float arm.

19. A liquid level gauge sub-assembly for use with a magnetically driven indicating dial assembly and a gauge head having a lower portion defining a passage formed on its lower surface, said gauge sub-assembly comprising:

a) a support arm having an upper end adapted for connection to the lower portion of a gauge head, a float arm attachment portion being located at a distance from said upper end, and a middle portion extending between said upper end and said float arm attachment portion;

said middle portion defining a side-accessible shaft passage extending between said upper end and said float arm attachment portion;

b) a magnet drive shaft rotatably mounted in said shaft passage and having a magnet holder located at an upper end and a shaft gear located at a distance from said upper end;

said upper end of said shaft extending beyond said upper end of said support arm for positioning said magnet holder within said passage of said gauge head;

c) a float arm having a first portion being pivotally connected to said float arm attachment portion of said support arm, having a float arm gear located on said first portion, and having a float attachment member being formed at a distance from said first portion;

said float arm gear engaging said shaft gear to impart rotational motion to said shaft and said magnet holder relative to said support arm and said gauge head upon rotation of said float arm relative to said support arm; and

d) said support arm further comprising at least one shaft retainer;

each said shaft retainer having opposing members formed integrally with said middle portion of said support arm to define a gap between said opposing members;

said gap having a width thereacross when no force is applied against said opposing members which is less than the diameter of the portion of the magnet drive shaft adjacent said opposing members.

20. A liquid level gauge sub-assembly for use with a magnetically driven indicating dial assembly and a gauge head, said gauge sub-assembly comprising:

a) a support arm having an upper end adapted for connection a gauge head, a float arm attachment portion being located at a distance from said upper end, and a middle portion extending between said upper end and said float arm attachment portion;

said middle portion defining a side-accessible shaft passage extending between said upper end and said float arm attachment portion;

b) a magnet drive shaft rotatably mounted in said shaft passage and having a magnet holder located at an upper end and a shaft gear located at a distance from said upper end;

said magnet holder of said magnet drive shaft including a resilient member which can be deformed to allow insertion of a magnet into said magnet holder and which thereafter biases said magnet against said magnet holder, thereby securing said magnet to said magnet holder; and

c) a float arm having a first portion being pivotally connected to said float arm attachment portion of said support arm, having a float arm gear located on said first portion, and having a float attachment member being formed at a distance from said first portion;

said float arm gear engaging said shaft gear to impart rotational motion to said shaft and said magnet holder relative to said support arm and said gauge head upon rotation of said float arm relative to said support arm.

21. A liquid level gauge sub-assembly according to claim 20, wherein insertion of a magnet having a flux field axis into said magnet holder predictably aligns said flux field axis with respect to said magnet holder.