Load indicating apparatus

• US 4,102,295 A
• Filed: 07/19/1976
• Issued: 07/25/1978
• Est. Priority Date: 05/01/1975
• Status: Expired due to Term

• Current Assignee: Crosby Group Incorporated
• Original Assignee: American Hoist & Derrick Company (Terex Corporation)
• Inventors: Crook, Edward J. Jr., Garrett, Charles R.
• Primary Examiner(s): Hartary, Joseph W.
• Application Number:
  US05/706,686
• Time in Patent Office: 736 Days
• Field of Search: 177/147, 177/145, 177/233, 177/232, 177/225, 177/234, 116/68, 116/114 R, 116/114 AJ, 116/124 AD, 116/129 E, 116/DIG. 34, 294/82 R
• US Class Current: 116/281
• CPC Class Codes: B66C 1/40 formed or fitted with load measuring or indicating devices
• CPC Class Codes: G01G 19/14 for weighing suspended loads G01G3/00 takes precedence; incorporation of weighing devices in cranes B66C1/40, B66C13/16
• CPC Class Codes: G01G 23/20 Indicating weight by mechanical means
• CPC Class Codes: Y10S 116/34 Tension indicating

Abstract

A load indicator is connected between a load line and a load handling member such as a hook. The indicator includes a hollow cylindrical housing, a plunger assembly including a transverse head slidably mounted in the housing, a pilot rod integral with the head and extending to a location outside the housing, means connecting a first end of the housing opposite the plunger rod and means connecting the plunger rod to the load line and to the load handling member, and a compression spring in the housing urging the plunger head toward the first end of the housing. The wall of the housing has several sight openings therethrough. A sight band of contrasting color is fixed to move with the plunger assembly inside the housing and to be visible through the sight openings. The spring is of strength to allow sufficient movement of the sight band so that a first color fills all of the sight openings when the load tensioning the load line, the indicator, and the load handling member reaches a predetermined rated value, and so that progressively less of the first color can be viewed through the sight openings as the tensioning load is reduced and the plunger head moves toward the first end of the housing.

Claims

1. A load indicator usable with load lifting machinery having a rated load capacity and connectable between a load line and a load handling member of the machinery, said indicator including:

a housing having a generally upright side wall partially defining a chamber, said housing having a lower end closed by an end wall and an upper end connectable to a load line;

said housing end wall being provided with an opening;

first connecting means securing a load line to said housing;

a deflectable plunger assembly located in said chamber and extending therefrom;

said deflectable plunger assembly being vertically movable in said chamber relative to said housing and freely rotatable in said chamber relative to said housing;

said housing side wall being provided with at least one sight opening permitting viewing said plunger assembly in the chamber from outside of the housing;

said plunger assembly having a transverse head with a side wall portion visually distinct from the outside of said housing side wall adjacent the sight opening and vertically intermediately movable in said chamber between a position toward the upper end of the chamber out of view through said opening and a position toward the lower end of the chamber totally covering said opening from within the chamber;

said plunger assembly having rod means secured to the head and extending outward of the chamber and housing through said end wall opening such that vertical movement of that portion of the rod means located outward of the chamber and housing results in directly corresponding movement of the transverse head in the chamber;

second connecting means on the rod means connecting it to a load handling member, said second connecting means including a threaded opening in said rod means in engagement with a threaded shank of the load handling member;

bias means in said chamber disposed between said head and a portion of the housing biasing said head toward the upper end of the chamber to locate said visually distinct side wall portion in the out-of-view position, said bias means including a disc spring located in said chamber assembled in said chamber under a percentage of spring deflection when said side wall portion is in the out-of-view position;

swivel bearing means disposed between said bias means and said portion of the housing to facilitate free rotation of the plunger assembly in said chamber relative to said housing when said plunger assembly is vertically deflected responsive to a load;

said head being vertically movable in said chamber against the action of the biasing means responsive to a tension load between the load line and the load handling member a distance representative of the extent of loading on the load handling member as compared to a rated load capacity toward said position with said side wall portion totally covering said opening;

said bias means being linearly calibrated to provide biasing force equal to a preselected load value upon movement of said visually distinct side wall portion from said out-of-sight position to said position totally covering said opening; and

a circumferential shoulder located on the side wall in the chamber in position to intercept said head and prevent further movement thereof after said side wall portion moves to said position totally covering said opening.

2. The indicator of claim 1 including:

a sleeve connected to said head side wall and extending therefrom to totally cover said opening when said head is in its out-of-view position, said sleeve and head side wall being visually mutually distinguishably color coded and presenting a color interface viewable through said opening.

3. The indicator of claim 1 including:

a second visually distinct side wall portion on said head and covering any portion of the opening not covered by the first visually distinct side wall portion.

4. The indicator of claim 1 wherein:

said disc spring includes a plurality of Belleville washers stacked in alternately facing and opposing relationship surrounding said rod means.

5. The indicator of claim 4 wherein:

said disc spring bears against said head and said swivel bearing means, said swivel bearing means being disposed between said disc spring and said housing end wall in said chamber.

6. The indicator of claim 1 including:

an adapter plug secured to said housing, closing the upper end of said chamber and constituting part of said first connecting means.

7. The indicator of claim 1 wherein:

said swivel bearing means is located in said chamber in bearing relationship to said end wall thereof;

said disc spring bears against said head and said swivel bearing means; and

said housing includes a second end wall closing the upper end of the chamber, and second swivel bearing means in said chamber disposed between the second end wall and said head to permit free rotation of said plunger assembly in said housing when said visually distinct side wall portion is located in said chamber in said position toward the upper end of said chamber out-of-view through said opening.

8. The indicator of claim 7 including:

a sleeve connected to said head side wall and extending therefrom to totally cover said sight opening when said head side wall is in its out-of-view position, said sleeve and head side wall being visually mutually distinguishably color coded and presenting a color interface viewable through said opening.

9. The indicator of claim 7 including:

a second visually distinct side wall portion on said head and covering every portion of the sight opening not covered by the first visually distinct side wall portion.