Device for mechanical weight bearing indication with load range capability

• US 7,493,810 B2
• Filed: 08/18/2006
• Issued: 02/24/2009
• Est. Priority Date: 08/18/2006
• Status: Expired due to Fees

• Current Assignee: Rensselaer Polytechnic Institute
• Original Assignee: Rensselaer Polytechnic Institute
• Inventors: Walczyk, Daniel F., Bornhoft, Stephen
• Primary Examiner(s): Patel; Harshad
• Assistant Examiner(s): DUNLAP, JONATHAN M
• Application Number:
  US11/465,641
• Publication Number:
  US 20080041169A1
• Time in Patent Office: 921 Days
• Field of Search: 738/623.81, 731/72, 738/625.3, 738/624.51, 200/1.B
• US Class Current: 73/172
• CPC Class Codes: G01L 1/04 by measuring elastic deformation of gauges, e.g. of springs
• CPC Class Codes: G01L 5/06 using mechanical means G01L5/042, G01L5/045 take precedence

Abstract

A mechanical load bearing indicator producing signals to a user when the user applies more than selected amounts of load between an extremity of the use and a surface. The indicator has a base plate adapted to establish a frame of reference with the surface, a load plate mounted for movement toward and away from the base plate and adapted to receive loads from the user'"'"'s extremity, and at least two snap domes mechanically engaged between the base plate and the load plate for generating two signals when more than two different respective loads are applied to the load plate by the extremity. The domes are either in series between the plates or are together in a dual dome containing both, or are one or more stacks of domes which individually collapse under incremental loads which are added together to form the selected lower and higher loads.

Claims

1. A mechanical load bearing indicator for producing signals to a user when the user applies more than selected amounts of load between an extremity of the use and a surface, comprising:

a base plate adapted to establish a frame of reference with the surface;

a load plate mounted for movement toward and away from the base plate and adapted to receive loads from the user'"'"'s extremity;

at least two snap domes stacked one above the other, and mechanically engaged between the base plate and the load plate for generating two signals when more than two different respective and selected loads are applied to the load plate by the extremity, the snap domes each being physically separate pieces of material from each other, each snap dome having a stable position and a snap-through unstable position; and

an intermediate plate between the at least two snap domes, and when a first lower one of the loads is applied to the load plate, a first one of the snap domes collapses and when a second higher one of the loads is applied to the load plate, a second one of the snap domes also collapses;

the at least two snap stacked domes being engaged in series between the base plate, the intermediate plate and the load plate, the first one of the snap domes being of a type to collapse at the first lower one of the loads and the second one of the snap domes being of a type to collapse at the second higher one of the loads so that when the first lower one of the loads is applied to the load plate, the first one of the snap domes collapses from its stable position and snaps-through to its unstable position, and when the second higher one of the loads is applied to the load plate, the second one of the snap domes also collapses from its stable position and snaps-through to its unstable position.

7. An indicator according to claim 1,wherein each of the snap domes comprises a plurality of snap disks in a stack, each snap disk collapsing when an incremental load is applied to that snap disk so that each of the selected loads is reached by adding the incremental loads of the snap disks in the stack.

2. An indicator according to claim l, wherein each snap dome is made of spring metal.

3. An indicator according to claim l, wherein each snap dome is made of a plastic.

4. An indicator according to claim l, wherein the base and the load plates each have a diameter of about 3 to 5 cm, and are adapted for engagement under the user'"'"'s heel or forefoot, the extremity comprising the user'"'"'s foot.

5. An indicator according to claim l, wherein the base plate with load plate and snap domes have a total height of approximately 0.6 to 1.2 cm.

6. An indicator according to claim l, wherein at least one of the snap domes comprises a plurality of snap disks in a stack, each snap disk collapsing when an incremental load is applied to that snap disk so that at least one of the selected loads is reached by adding the incremental loads of the snap disks in the stack.

8. An indicator according to claim l, wherein each snap dome has a concave side with the concave side of one of the snap domes facing the intermediate plate and the concaveside of the other snap plate facing either the load plate or the base plate.

9. An indicator according to claim l, wherein each snap dome has a concave side facing the intermediate plate.

10. An indicator according to claim l, wherein each snap dome has a concave side facing away from the intermediate plate.