Nonthreaded load sensing probe

• US 5,402,689 A
• Filed: 11/04/1993
• Issued: 04/04/1995
• Est. Priority Date: 11/04/1993
• Status: Expired due to Fees

• Current Assignee: Helm Instrument Co., Inc.
• Original Assignee: Helm Instrument Co., Inc.
• Inventors: Grogan, Richard J.
• Primary Examiner(s): Chilcot, Jr., Richard E.
• Assistant Examiner(s): Dougherty, Elizabeth L.
• Application Number:
  US08/147,828
• Time in Patent Office: 516 Days
• Field of Search: 73/862.541, 73/862.631, 73/862.632, 73/862.635, 73/862.06, 73/796, 73/768, 73/774, 73/781, 73/151-153, 166/138, 166/139, 166/211, 166/216, 166/217
• US Class Current: 73/862.635
• CPC Class Codes: G01L 1/2218 the supports being of the column type, e.g. cylindric, adapted for measuring a force along a single direction
• CPC Class Codes: G01L 25/00 Testing or calibrating of apparatus for measuring force, torque, work, mechanical power, or mechanical efficiency
• CPC Class Codes: G01L 5/0004 Force transducers adapted for mounting in a bore of the force receiving structure G01L5/0009 takes precedence
• CPC Class Codes: G01L 5/226 to manipulators, e.g. the force due to gripping

Abstract

An apparatus for sensing forces applied to a structure includes a generally cylindrical body having a pair of end portions and a smaller diameter intermediate portion with a central aperture extending longitudinally through the body. The end portions are slotted to form radially outwardly translatable legs for engaging a wall of a cavity formed in the structure. Strain gauges are attached to the intermediate portion for sensing forces applied to the structure when the body is positioned in the cavity and the legs are engaging the wall of the cavity. The wall of the central aperture has a pair of threaded sections for threadably receiving bushing and bearing assemblies inserted from opposite ends of the central aperture. Each of the assemblies has a tapered surface for radially outwardly translating the legs. One of the assemblies has an allen wrench receiving cavity accessible through one of the open ends of the central aperture and the other one of assemblies has an allen wrench receiving cavity accessible from outside the body.

Claims

1. An apparatus for sensing forces applied to a structure comprising:

a generally cylindrical body having a pair of end portions extending from opposite end surfaces thereof, an intermediate portion having a smaller outside diameter than an outside diameter of either of said end portions and extending between said end portions, and a central aperture extending along a longitudinal axis of said body and having an open end at each of said opposite end surfaces;

radially outwardly translatable engaging means formed in each of said end portions for engaging a wall of a cavity formed in a structure;

force sensing means attached to said intermediate portion for sensing forces applied to the structure when said body is positioned in the cavity and said engaging means are engaging the wall of the cavity;

a wall of said central aperture having a threaded section formed in each of said end regions; and

a pair of means for radially outwardly translating said engaging means into engagement with the wall of the cavity formed in the structure, one of said means for translating threadably engaging one of said threaded sections and having means for rotating said one means for translating accessible through one of said open ends of said central aperture, and another one of said means for translating threadably engaging another one of said threaded regions and having means for rotating said another means for translating accessible from outside said body.

2. The apparatus according to claim 1 wherein said engaging means includes a radially outwardly extending circumferential flange formed on each of said end portions.

3. The apparatus according to claim 1 wherein each of said end portions has at least two slots formed therein, said slots extending along said longitudinal axis from an associated one of said end surfaces toward said intermediate portion and from an outer surface of said end portion to said central aperture, and wherein said means for engaging includes legs formed in said end portion between said slots.

4. The apparatus according to claim 1 wherein each of said end portions has at four slots formed therein, said slots extending along said longitudinal axis from an associated one of said end surfaces toward said intermediate portion and from an outer surface of said end portion to said central aperture, and wherein said means for engaging includes legs formed in said end portion between said slots.

5. The apparatus according to claim 1 wherein said force sensing means includes a plurality of strain gauges.

6. The apparatus according to claim 1 wherein each of said means for translating includes a bushing and bearing assembly having threads formed thereon for threadably engaging an associated one of said threaded sections and a tapered surface tapering from a first diameter larger than a diameter of said central aperture at an associated open end thereof and a second diameter smaller than a diameter of said central aperture at said associated open end thereof.

7. The apparatus according to claim 6 wherein said bushing and bearing assembly includes a generally cylindrical assembly body having said threads formed at one end and an opposite end, an enlarged portion formed between said threads and said opposite end, and a tapered cone having an aperture formed therein for receiving said opposite end of said assembly body.

8. The apparatus according to claim 7 wherein said bushing and bearing assembly includes a bearing washer and a bushing collar, said beating washer and said bushing collar each having an aperture formed therein for receiving said opposite end of said assembly body, said tapered cone being positioned between said enlarged portion and said bearing washer and said bearing washer being positioned between said tapered cone and said bushing collar.

9. The apparatus according to claim 8 wherein said bushing and bearing assembly includes a pin extending through transverse apertures formed in said assembly body and said bushing collar for retaining said tapered cone, said bearing washer and said bushing collar on said assembly body.

10. The apparatus according to claim 8 wherein said bearing washer is formed of a ring of fiber material and a metal backing ring.

11. The apparatus according to claim 1 wherein said means for rotating includes a hexagonal cross section cavity formed in each of said means for translating.

12. An apparatus for sensing forces applied to a structure comprising:

a generally cylindrical body having a pair of end portions extending from opposite end surfaces thereof, an intermediate portion having a smaller outside diameter than an outside diameter of either of said end portions and extending between said end portions, and a central aperture extending along a longitudinal axis of said body and having an open end at each of said opposite end surfaces;

radially outwardly translatable engaging means formed in each of said end portions including a radially outwardly extending circumferential flange formed on each of said end portions for engaging a wall of a cavity formed in a structure;

force sensing means attached to said intermediate portion for sensing forces applied to the structure when said body is positioned in the cavity and said engaging means are engaging the wall of the cavity;

a wall of said central aperture having a threaded section formed in each of said end regions; and

a pair of means for radially outwardly translating said engaging means into engagement with the wall of the cavity formed in the structure, each of said means for translating including a bushing and bearing assembly having threads formed thereon for threadably engaging an associated one of said threaded sections and a tapered surface tapering from a first diameter larger than a diameter of said central aperture at an associated open end thereof and a second diameter smaller than a diameter of said central aperture at said associated open end thereof, one of said means for translating having means for rotating said one means for translating accessible through one of said open ends of said central aperture, and another one of said means for translating having means for rotating said another means for translating accessible from outside said body.

13. A load sensing probe for sensing forces applied to a machine dement comprising:

a generally cylindrical body having a pair of end portions of substantially equal outside diameter extending from opposite end surfaces thereof, an intermediate portion having a smaller outside diameter than said outside diameter said end portions and extending between said end portions, and a central aperture extending along a longitudinal axis of said body and having an open end at each of said opposite end surfaces;

four slots formed in each of said end portions and extending along said longitudinal axis from an associated one of said end surfaces toward said intermediate portion and from an outer surface of said end portion to said central aperture, said end portions forming legs between adjacent ones of said slots, said legs being radially outwardly translatable for engaging a wall of a cavity formed in a machine element;

force sensing means attached to said intermediate portion for sensing forces applied to the machine dement when said body is positioned in the cavity and said legs are engaging the wall of the cavity;

a wall of said central aperture having a threaded section formed in each of said end regions; and

a pair of means for radially outwardly translating said engaging means into engagement with the wall of the cavity formed in the structure, one of said means for translating threadably engaging one of said threaded sections and having means for rotating said one means for translating accessible through one of said open ends of said central aperture, and another one of said means for translating threadably engaging another one of said threaded regions and having means for rotating said another means for translating accessible from outside said body.

14. The apparatus according to claim 13 wherein each said means for translating includes a generally cylindrical assembly body having threads formed at one end and an opposite end, an enlarged portion formed between said threads and said opposite end, a tapered cone having an aperture formed therein for receiving said opposite end of said assembly body, said tapered cone having a tapered surface tapering from a first diameter larger than a diameter of said central aperture at an associated open end thereof and a second diameter smaller than a diameter of said central aperture at said associated open end thereof, a bearing washer and a bushing collar, said bearing washer and said bushing collar each having an aperture formed therein for receiving said opposite end of said assembly body, said tapered cone being positioned between said enlarged portion and said bearing washer and said bearing washer being positioned between said tapered cone and said bushing collar.

15. The apparatus according to claim 14 wherein said means for translating includes a pin extending through transverse apertures formed in said assembly body and said bushing collar for retaining said tapered cone, said bearing washer and said bushing collar on said assembly body.

16. The apparatus according to claim 14 wherein said means for rotating includes a hexagonal cross section cavity formed in said threaded end of said assembly body of said one of said means for translating and a hexagonal cross section cavity formed in said opposite end of said assembly body of said another one of said means for translating.