Liquid level gauge with hinged float arm

• US 6,216,534 B1
• Filed: 08/28/1998
• Issued: 04/17/2001
• Est. Priority Date: 08/28/1998
• Status: Expired due to Term

• Current Assignee: Rochester Gauges Incorporated
• Original Assignee: Rochester Gauges Incorporated
• Inventors: Ross, Herbert G. Jr., Horvath, Agoston
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): LOO, DENNIS S
• Application Number:
  US09/141,504
• Time in Patent Office: 963 Days
• Field of Search: 733/17, 733/05, 733/06, 733/09, 733/13, 733/14, 733/15, 733/18, 733/19, 733/20, 733/21, 733/22, 733/225, 116/229
• US Class Current: 73/317
• CPC Class Codes: F17C 2250/0413 with floats
• CPC Class Codes: G01F 23/32 using rotatable arms or other pivotable transmission elements
• CPC Class Codes: G01F 23/38 using magnetically actuated indicating means

Abstract

A float-type liquid level gauge (20) is provided for measuring the level of a liquid within a storage tank (22). The gauge includes a gauge head (30) adapted for mounting to a portion of liquid storing container, a support arm (32) connected to the gauge head and depending therefrom into the tank, a float arm (34) including an elongate inner arm section (46), an elongate outer arm section (48) and a hinge section (50), and a float (36) connected to the outer end of the float arm. The inner section of the float arm is pivotally connected to the support arm for movement through an arc defining a first plane. The hinge section is connected at a first end to an outer end of the inner arm section and connected at an opposite end to the inner end of the outer arm section. The hinge section is deflectable to allow movement of the outer arm section between a first configuration in which the outer arm section is in a predetermined position with respect to the inner arm section, and a second configuration in which the outer arm section is not in the predetermined position. The hinge section provides a biasing force for urging the outer arm section into the first configuration. This arrangement allows the outer arm section to temporarily deflect with respect to the inner arm section to avoid damage if the float or float arm encounters an obstacle as the gauge is being installed in the storage tank.

Claims

1. A liquid level gauge comprising:

(a) a gauge head adapted for mounting to a portion of a liquid storing container;

(b) a support arm rigidly connected to said gauge head and depending therefrom;

(c) a float arm including an elongate inner arm section, an elongate outer arm section and a hinge section;

said inner arm section being pivotally connected to said support arm for movement through an arc defining a first plane;

said hinge section being connected at a first end to an outer end of said inner arm section and connected at an opposite end to an inner end of said outer arm section;

said hinge section being deflectable to allow movement of said outer arm section between a first configuration in which said outer arm section is in a predetermined position with respect to said inner arm section and a second configuration in which said outer arm section is not in said predetermined position with respect to said inner arm section;

said hinge section providing a biasing force for urging said outer arm section into said first configuration; and

(d) a float connected to an outer end of said outer arm section, said float being buoyant so as to remain at the surface of a liquid.

2. A gauge according to claim 1, wherein said predetermined position constitutes said outer arm section being longitudinally aligned with said inner arm section.

3. A gauge according to claim 1, wherein said hinge section comprises a close wound cylindrical helical extension spring, said spring, when in an unflexed condition, defining a cylindrical bore and having an initial tension.

4. A gauge according to claim 3, wherein said outer end of said inner arm section and said inner end of said outer arm section are separated by a distance within a range of about 1.25 inches to about 2.00 inches.

5. A gauge according to claim 3, wherein said spring has an initial tension within a range of about 5 pounds to about 7 pounds.

6. A gauge according to claim 3, further comprising:

a first circular groove formed on said outer arm section near said inner end;

a second circular groove formed on said inner arm section near said outer end;

wire segments formed on each end of said spring;

each said wire segment being bent inwardly into a region constituting a longitudinal extension of said cylindrical bore of said spring; and

said inner and outer ends, respectively, of said outer and inner arm sections being positioned within said bore and said wire segments being positioned within said first and second circular grooves so as to secure said arm sections to said hinge section.

7. A gauge according to claim 3, further comprising:

upset regions formed near said inner end of said outer arm section and near said outer end of said inner float arm section;

each said upset region having a maximum lateral dimension which exceeds the diameter of said spring bore when said spring is in said unflexed condition;

portions of said arm sections including said upset regions being positioned within said spring bore, said upset regions radially flexing adjacent portions of said spring and producing a bias force between said spring and said upset regions, thereby securing said arm sections to said hinge section.

8. A gauge according to claim 1, wherein said hinge section comprises first and second guide members and an elastic member connected therebetween;

said first guide member being connected at a first end to said inner end of said outer arm section;

said second guide member being connected at a first end to said outer end of said inner arm section;

each said guide member including a longitudinally oriented body portion and a terminal portion, said terminal portion being disposed at a second end of said body portion and defining a mating surface facing away from said body portion and generally perpendicular to said longitudinal direction;

each said guide member defining a passage formed through said mating surface and extending into said body portion to an anchor point;

said elastic member having a first end secured at the anchor point of said first guide member, extending through said passages in said first and second guide members, and having a second end secured at the anchor point of said second guide member;

said elastic member providing a biasing force for urging said mating surfaces into juxtaposition.

9. A gauge according to claim 8, wherein said elastic member is a cylindrical helical extension spring held in tension when said mating surfaces are juxtaposed.

10. A gauge according to claim 8, further comprising at least one magnet positioned adjacent to one of said terminal portions;

said magnet producing a magnetic force attracting said mating surfaces of said guide members together when said mating surfaces are juxtaposed.

11. A gauge according to claim 1, wherein said hinge section is only deflectable in predetermined directions, said predetermined directions not lying in said first plane.

12. A gauge according to claim 11, wherein said hinge section comprises a flat leaf spring;

said spring having a rectangular cross section with a thickness and a width, said thickness being smaller than said width, and said spring being connected to said inner arm section such that said width is oriented in a substantially vertical direction during use.

13. A gauge according to claim 12, wherein said spring includes ends which are connected to said ends of said arm sections with welds.

14. A gauge according to claim 12, wherein said spring includes ends which are connected to said ends of said float arm sections with pins.

15. A gauge according to claim 11, wherein said hinge section comprises:

a first hinge member and a second hinge member pivotally connected to one another to allow relative movement in a second plane;

said first hinge member being connected to said inner end of said outer arm section;

said second hinge member being connected to said outer end of said inner arm section such that said second plane is oriented in a substantially horizontal direction during use; and

an elastic member connected between said arm sections and providing a biasing force for urging said outer arm section into said first position.

16. A gauge according to claim 15, wherein said elastic member is a elastomer sleeve defining a bore;

said sleeve being connected to each said arm section;

said hinge members being positioned within said bore.

17. A gauge according to claim 15, wherein said elastic member is a cylindrical helical spring connected to each said arm section;

said hinge members being positioned within the bore of said spring.

18. A screw-in gauge for measuring the level of liquid in a tank, said gauge comprising:

(a) a gauge head having a threaded portion adapted for screw-in mounting into a threaded fitting of said tank, said threaded portion defining a mounting axis for said gauge;

(b) a support arm rigidly connected to said gauge head and depending therefrom into said tank along said mounting axis;

(c) a float arm including an elongate inner arm section, an elongate outer arm section and a hinge section;

said inner arm section being pivotally connected to said support arm for movement through an arc defining a first plane;

said hinge section being connected at a first end to an outer end of said inner arm section and connected at an opposite end to an inner end of said outer arm section;

said hinge section being deflectable in response to a force directed against said outer arm section along a line lying within a second plane which is perpendicular to said mounting axis;

said hinge section providing a biasing force for urging said outer arm section into a predetermined position with respect to said inner arm section; and

(d) a float connected to an outer end of said outer arm section, said float being buoyant so as to remain at the surface of said liquid.

19. A gauge according to claim 18, further comprising:

a drive shaft mounted in said support arm to allow rotation about the longitudinal axis of said shaft, said shaft having a first end disposed within a cavity formed in said gauge head and a second end disposed at the connection point of said float arm to said support arm;

a magnet fixed on said first end of said drive shaft to rotate with said shaft;

a first gear fixed on said second end of said drive shaft to rotate with said shaft;

a second gear fixed on said inner arm section of said float arm to pivot with said inner arm section; and

said first and second gears each having teeth which are operably engaged so that pivoting of said second gear produces a corresponding rotation of said first gear;

whereby angular movement of said inner arm section of said float arm with respect to said support arm produces rotational movement of said magnet.

20. A gauge according to claim 19, further comprising a magnetically-coupled indicator dial mounted on said gauge head, said dial including an indicator, said indicator being responsive to movement of said magnet within said gauge head;

whereby angular movement of said inner arm section of said float arm with respect to said support arm is indicated outside said tank by said indicator.

21. A float arm for a liquid level gauge having a support member and a float, said float arm comprising:

an elongate inner arm section having an inner end and an outer end, said inner end being adapted for pivotal connection to said support member;

a hinge section connected at a first end to said outer end of said inner arm section;

an elongate outer arm section having an inner end and an outer end, said inner end being connected to a second end of said hinge section and said outer end being adapted for connection to said float;

said hinge section being deflectable to allow movement of said outer arm section between a first configuration in which said outer arm section is in a predetermined position with respect to said inner arm section and a second configuration in which said outer arm section is not in said predetermined position with respect to said inner arm section;

said hinge section providing a biasing force for urging said outer arm section into said first configuration.

22. A float arm according to claim 21, wherein said hinge section comprises a close wound cylindrical helical extension spring, said spring, when in an unflexed condition, defining a cylindrical bore and having an initial tension.

23. A float arm according to claim 21, wherein said hinge section comprises first and second guide members and an elastic member connected therebetween;

said first guide member being connected at a first end to said inner end of said outer arm section;

said second guide member being connected at a first end to said outer end of said inner arm section;

each said guide member including a longitudinally oriented body portion and a terminal portion, said terminal portion being disposed at a second end of said body portion and defining a mating surface facing away from said body portion and generally perpendicular to said longitudinal direction;

each said guide member defining a passage formed through said mating surface and extending into said body portion to an anchor point;

said elastic member having a first end secured at the anchor point of said first guide member, extending through said passages in said first and second guide members, and having a second end secured at the anchor point of said second guide member;

said elastic member providing a biasing force for urging said mating surfaces into juxtaposition.

24. A float arm according to claim 21, wherein said hinge section is deflectable only in predetermined directions.

25. A float arm according to claim 24, wherein said hinge section comprises a single leaf flat spring;

said spring having a rectangular cross section with a thickness and a width, said thickness being smaller than said width, and said spring being connected to said inner arm section such that said width is oriented in a substantially vertical direction during use.

26. A float arm according to claim 24, wherein said hinge section comprises:

a first hinge member and a second hinge member pivotally connected to one another to allow relative movement in a plane;

said first hinge member being connected to said inner end of said outer arm section;

said second hinge member being connected to said outer end of said inner arm section such that said plane is oriented in a substantially horizontal direction during use; and

an elastic member connected between said arm sections and providing a biasing force for urging said outer arm section into said first configuration.