Apparatus for load and displacement sensing

• US 5,325,869 A
• Filed: 12/16/1991
• Issued: 07/05/1994
• Est. Priority Date: 12/16/1991
• Status: Expired due to Fees

• Current Assignee: Theodore J. Stokes
• Original Assignee: Theodore J. Stokes
• Inventors: Stokes, Theodore J.
• Primary Examiner(s): Pellegrino, Stephen C.
• Assistant Examiner(s): Tucker, Guy V.
• Application Number:
  US07/808,105
• Time in Patent Office: 932 Days
• Field of Search: 128/779, 128/782, 128/774, 73/767, 73/768, 73/779, 73/841, 73/862.041, 73/862.042, 73/862.043, 73/862.046, 73/862.69, 73/172, 73/DIG. 3, 338/32 H, 177/DIG. 5
• US Class Current: 600/592
• CPC Class Codes: A43B 1/0054 provided with magnets, magnetic parts or magnetic substances
• CPC Class Codes: A43B 13/00 Soles; Sole-and-heel integral units
• CPC Class Codes: A43B 17/00 Insoles for insertion, e.g. footbeds or inlays, for attachment to the shoe after the upper has been joined
• CPC Class Codes: A43B 3/34 with electrical or electronic arrangements
• CPC Class Codes: A43B 3/44 with sensors, e.g. for detecting contact or position
• CPC Class Codes: A61B 5/1036 Measuring load distribution, e.g. podologic studies
• CPC Class Codes: G01L 1/14 by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators
• CPC Class Codes: G01L 5/169 using magnetic means

Abstract

An apparatus for load and displacement sensing adapted for measuring normal and shear forces exerted on load bearing portions of a body. The apparatus includes a deformable pad and a plurality of sensors. Each sensor includes at least one magnet and at least one Hall-effect transducer affixed to opposite sides of the deformable pad. Normal forces are measured utilizing magnets having a planar North and South polarizations and the magnitude and direction of shear forces are measured utilizing magnets having alternating North and South pole segments disposed longitudinally therewithin. In another embodiment, normal and shear forces are measured utilizing a magnet having a point-magnetization. The force exerted on the body deforms the pad, bringing the magnet in close proximity to the transducer, which senses the change in the magnetic flux density.

Claims

1. An apparatus for load and displacement sensing adapted for measuring the magnitude and direction and two-dimensional shear forces exerted upon the load bearing portions of a body, the apparatus comprising:

a deformable pad having a first and second side, and

a plurality of sensors, each sensor having three magnets affixed to one side of said deformable pad and three transducers for sensing the magnetic field strength affixed to the other side of said deformable pad, each transducer being aligned with one of said magnets and having an output which varies according to the magnitude and direction of said normal and two-dimensional shear forces, said forces moving said magnets in relation to said transducers, said magnets are oriented so that their respective pole segments are disposed 120°

from each other.