Tension Indicating Patents (Class 116/DIG34)
  • Patent number: 6152665
    Abstract: A direct tension indicating washer including a body having an internal opening formed therein and at least one arched tab connected to the body. The arched tab has a fixed end integral with the body and a distal end movable with respect to the body. Indicia is formed on the arched tab and when the direct tension indicating washer is tensioned, the arched tab moves away from the body. Alignment of the indicia with a reference indicates proper tension. Another embodiment of the invention is a direct tension indicating washer having a body having an internal opening formed therein and at least one arch connected to the body. The arch has a first end integral with the body, a second end integral with the body and an intermediate portion between the first end and second end. The intermediate portion is positioned above a top surface of the body.
    Type: Grant
    Filed: August 20, 1999
    Date of Patent: November 28, 2000
    Assignee: Applied Bolting Technology Products, Inc.
    Inventors: Ivan Wayne Wallace, John A. Herr
  • Patent number: 5913647
    Abstract: A mechanical sensor for use with bolts, nuts, eye bolts and other fasteners is provided to sense fastener tension and to mechanically indicate that tension and changes therein by mechanically measuring deformation of the substrate being clamped by the fastener relative to the distortion or lack thereof in the substrate immediately adjacent the deformed substrate. The differential substrate deformation produces measurable and often clearly visible movement of a portion of the sensor. Such movement may be interrogated through utilization of visual, optical, electro-optical means as desired.
    Type: Grant
    Filed: December 20, 1996
    Date of Patent: June 22, 1999
    Assignee: Structural Integrity Monitoring Systems, Inc.
    Inventor: Malcolm H. Hodge
  • Patent number: 5769581
    Abstract: A direct tension indicating and maintaining washer has a first surface having at least one protuberance formed thereon and a second surface having at least one indentation formed therein opposite the protuberance. The inner diameter of the direct tension indicating and maintaining washer has an inner diameter wall meeting the second surface at an inner diameter edge. The outer diameter has an outer diameter wall meeting the second surface at an outer diameter edge. The inner diameter edge and the outer diameter edge lie in different planes. This causes the flattened direct tension indicating and maintaining washer to exert force against a bolt and maintain bolt tension. An alternative direct tension indicating and maintaining washer includes indicating material positioned in the indentation and a channel formed in the second surface leading from the indentation to the outside diameter of the direct tension indicating washer.
    Type: Grant
    Filed: February 21, 1997
    Date of Patent: June 23, 1998
    Assignee: Applied Bolting Technology Products, Inc.
    Inventors: Ivan Wayne Wallace, John A. Herr
  • Patent number: 5586851
    Abstract: A prestress-monitoring element for screw-type anchors is arranged to be inserted like a washer between a nut and an article to be fixed and includes a pressure ring and an expansion ring. If the nut provided for fixing is tightened, then the resultant axial prestress causes the pressure ring to expand the expansion ring until the nut lies against the expansion ring. In this end position, a prestress required by the construction of the prestress-monitoring element is achieved. The position of the nut on the pressure ring can be monitored visually, as a result of which the prestress can be indirectly monitored.
    Type: Grant
    Filed: May 19, 1995
    Date of Patent: December 24, 1996
    Assignee: fischerwerke, Artur Fischer GmbH & Co KG
    Inventor: Manfred Haage
  • Patent number: 5584627
    Abstract: A load indicating fastener composed of a body (2) having an abutment (9) which is moved by the changing length of the body (2) under an applied load, and a load sensing member (10) composed of an element (11) disposed in the direction in which a load is applied to the body (2) when the fastener is in the user characterized in that the element (11) is of elongated U-shape, a first limb (13) of the U providing an anchorage part (14) which is rigidly anchored to the body (2), the closed end of the U providing a bearing part (15) which bears on the abutment (9) so as to move with the abutment relative to the anchorage part (14) in response to a load applied to the body, and a second limb (16) of the U having an indicator (17) at its outer end which responds movement of the bearing part (15) and registers the applied load related to that movement on a scale (19).
    Type: Grant
    Filed: January 9, 1995
    Date of Patent: December 17, 1996
    Assignee: Stanley Ceney
    Inventors: Stanley Ceney, John A. B. Hirst
  • Patent number: 5487632
    Abstract: A pre-load indicating washer in which a plurality of protuberances, struck and partially sheared from the annular body of the washer, are pushed under load back into a corresponding plurality of indentations in the annular body which are formed when the protuberances are formed. The mass of material defined by each protuberance/indentation pair is concentrated along the lengthwise central region of the protuberance/indentation pair, thereby stiffening the protuberance, so that when load is applied to the washer, the protuberance will first undergo elastic deformation prior to collapsing back into the indentation from which it was formed.
    Type: Grant
    Filed: June 20, 1994
    Date of Patent: January 30, 1996
    Assignee: J & M Turner, Inc.
    Inventors: A. Craig Hood, Lloyd J. Larson
  • Patent number: 5452679
    Abstract: An improved hoisting device, such as a hook, shackle, ring, link, or the like, includes indicia for determining deformation damage to the device from overstressing. The indicia includes components which assume a predetermined geometrical configuration, such as a line segment co-linearly aligned with another line segment or dot, as the device is in an unstressed and undeformed state, and which do not assume the predetermined configuration if the device have been damaged from over-stressing. The indicia also includes cooperating components for dynamically indicating the magnitude of stressing relative to the maximum design stress of the device. The indicia is adapted for both close proximity and remote stressing determinations.
    Type: Grant
    Filed: January 26, 1994
    Date of Patent: September 26, 1995
    Assignee: Columbus McKinnon Corporation
    Inventor: Gary W. Eckley
  • Patent number: 5415508
    Abstract: A compression system for joining structural components under tension utilizing a bolt with a shank, an end and a head, one or more flat washers and one or more compression springs. One of the structural components, the bolt end and the nut carry indicia means that form a linear relationship with each other when the system is in an initial tensioned and starting condition and form a selectably angular relationship when the nut is tightened on the bolt a predetermined amount. The system enables the consistent uniform tightening of the system elements to combine structural components and provide consistent spring loading throughout.
    Type: Grant
    Filed: March 16, 1994
    Date of Patent: May 16, 1995
    Assignee: Universal Loading Spring Corp.
    Inventor: Walter F. Pleva
  • Patent number: 5384930
    Abstract: A broom with a flexible coupling in the handle comprising a head having a threaded aperture therein. A handle is formed as a long upper section adapted to be held by a user and a shorter lower section being provided with screw threads for releasably coupling with the threaded aperture in the head. A coil spring couples the lower end of the upper section with the upper end of the lower section with the spring encompassing a space between the lower end of the upper section and the upper end of the lower section. The coupling may further include an adhesive in a rupturable membrane to provide a more secure attachment and a dye in a similar membrane for indicating proper attachment.
    Type: Grant
    Filed: March 10, 1994
    Date of Patent: January 31, 1995
    Inventor: Thomas A. Uno
  • Patent number: 5370483
    Abstract: A pre-load indicating washer in which a plurality of protuberances, struck and partially sheared from the annular body of the washer, are pushed under load back into a corresponding plurality of indentations in the annular body which are formed when the protuberances are formed. The mass of material defined by each protuberance/indentation pair is concentrated along the lengthwise central region of the protuberance/indentation pair, thereby stiffening the protuberance, so that when load is applied to the washer, the protuberance will first undergo elastic deformation prior to collapsing back into the indentation from which it was formed.
    Type: Grant
    Filed: June 24, 1993
    Date of Patent: December 6, 1994
    Assignee: J & M Turner, Inc.
    Inventors: A. Craig Hood, Lloyd J. Larson
  • Patent number: 5226765
    Abstract: A load indicating fastener such as a bolt (10) or stud, has a shank (12) which is subject to tensile loading in use. The shank (12) has an axially extending bore (22) which receives a first gauge pin (30) anchored at its inner end (32) to the shank (12) and protruding outwards beyond an end face (16) of the fastener. An indicating member (40) is rotatable on the protruding portion of the gauge pin (30) between the end face (16) of the fastener and the head (34) of the pin (30), so that the indicating member (40) is free to rotate when the shank (12) of the fastener is unstressed but when the shank (12) is subject to a predetermined tensile loading is held against rotation by contact with the end face (16) of the fastener. A second gauge pin (42) is received within an axially extending bore (36) in the first gauge pin (30) and is anchored at is inner end and protrudes outwards beyond the outer end of the first gauge pin (30).
    Type: Grant
    Filed: April 16, 1992
    Date of Patent: July 13, 1993
    Assignee: Rotabolt Limited
    Inventor: Brian Walton
  • Patent number: 5213366
    Abstract: A shield arrangement is arranged for receiving a seat belt, typically within a self-propelled vehicle. The shield structure is formed of shape retentent material having loop members to convex outer surface thereof to receive the safety belts to effect distribution of force during impact about a larger surface area of an individual's body. A modification of the invention includes reinforcing members, as well as indicator fluid, to indicate fatigue of the shield structure.
    Type: Grant
    Filed: June 19, 1992
    Date of Patent: May 25, 1993
    Inventor: Ronald R. Sweger, Jr.
  • Patent number: 5199835
    Abstract: A bolt tension indicator having an annular washer part of concave cross section for fitment beneath the head of a bolt or beneath a nut, the indicator being made of spring steel and having at least one projecting tab element continuous with the annular washer part so that the lying flat of the tab element against a clamping face indicates a tension in the bolt.
    Type: Grant
    Filed: May 27, 1992
    Date of Patent: April 6, 1993
    Inventor: Arthur M. Turner
  • Patent number: 5129350
    Abstract: Apparatus and method are provided for indicating when a predetermined amount of tension has been applied to a band by a banding tool. The apparatus includes a housing, a lever for transferring pressure, and a tension indicator. As a tool handle is rotated to apply tension to a band, pressure is applied to the lever. When the tension applied is substantially equal to the predetermined tension, the lever pivots and activates the indicator, indicating to the operator of the banding tool that sufficient tension has been applied. In one embodiment, the indicator extends into the path of the rotating tool handle, thus preventing the operator from applying further tension to the band.
    Type: Grant
    Filed: September 6, 1991
    Date of Patent: July 14, 1992
    Assignee: Band-It-Idex, Inc.
    Inventor: Miklos B. Marelin
  • Patent number: 5102273
    Abstract: A bolt for attaching a first member to a second with a desired compressive force. The bolt has a cylindrical body with a threaded section on a first end and a head on a second end. The cylindrical body had a longitudinal bore which extends to a cross bore in the head. A pin located in the cross bore has a first flat surface separated from as second flat surface by a shoulder. A rod located in the longitudinal bore has a first end fixed to the cylindrical body and a second end that is located on the first flat surface. A spring acts on the pin to hold the shoulder against the rod. An input torque applied to the head causes the threads to move into threads on the second body. When the head engages the first body, further torque results in expansion or elongation of the cylindrical body. The rod freely moves in the longitudinal bore and when a predetermined elongation occurs corresponding to the depth of the shoulder on the pin, the spring moves the pin to align the second flat surface over the rod.
    Type: Grant
    Filed: February 25, 1991
    Date of Patent: April 7, 1992
    Assignee: Allied-Signal Inc.
    Inventor: Nickie L. Stanage
  • Patent number: 5088867
    Abstract: A failure indicating device wherein a fluid is encased within a bore in a fastener. In another embodiment of the invention, the fluid is encased within a thin walled capsule which in turn is encapsulated within a bore in the fastener. Upon failure of the fastener, the encased fluid will leak out into the external surface and its detection will indicate that the fastener has failed. The stress which causes the fastener to fail will also assist the fluid to leak out onto its external surface. To facilitate the leakage of the fluid, one or more shallow and narrow groove(s) may be machined onto the external surface of the fastener so that the leaked fluid will travel along this groove(s) to the preferred external end of the fastener. This is desirable in cases where only one side of the joint is accessible.
    Type: Grant
    Filed: November 26, 1990
    Date of Patent: February 18, 1992
    Inventor: Kam C. Mun
  • Patent number: 4992778
    Abstract: The invention provides a method and means for detecting and giving warning of a predetermined status of cordage through the change of a warning element from one condition to a different condition in response to a change in the status of the cordage.
    Type: Grant
    Filed: December 22, 1989
    Date of Patent: February 12, 1991
    Assignee: The University of New Mexico
    Inventors: Robert G. McKeen, Robert W. Spake
  • Patent number: 4988246
    Abstract: Apparatus for indicating incomplete and complete fastening of a screw includes a washer and a ring of a generally flat synthetic resin sheet. The washer includes a pair of washer portions of a generally flat, round shape and a joint portion interconnecting the washer portions to face them in opposite directions to enable the washer portions to receive a shank of a screw in the openings thereof. The lengthwise section of the joint portion forms generally a U shape. The ring is made of a generally round, deformable material and is inserted between the pair of washer portions thus facing each other. The deformable material is expanded radially outward, when compressed by the washer portions receiving the shank of the screw when fastened. Upon the compressive force reaching a predetermined value, the ring will be broken due to the pair of washer portions overlaying one another.
    Type: Grant
    Filed: February 23, 1990
    Date of Patent: January 29, 1991
    Assignee: Kyodo Electric Co., Ltd.
    Inventors: Minoru Yoshida, Teruo Arai, Toshiro Ishikawa, Masaji Shimada, Shigeru Susaki, Yukihiko Yamada, Hisao Ohta, Katsuyoshi Nagami, Kazutami Hayajiri, Takaharu Yoshioka, Shigo Hirai, Tosio Ichida, Nobuyuki Ishii
  • Patent number: 4981404
    Abstract: For anchoring heavy machinery to foundations, previously tensioned stress-level indicating bolt connectors are provided. In a top axial cavity of the connector, threads are provided to mount an angularly adjustable stress-level indicating pin. In use, when the design tension stress level is reached and the connector thereby extended, angular freedom or restraint of the gaging pin indicates that the pre-set stress has been reached or exceeded. Indicia angularly arranged on the connector end facilitate adjustment of the pin to provide upper or lower stress levels.
    Type: Grant
    Filed: October 16, 1989
    Date of Patent: January 1, 1991
    Assignee: Arrow Support Systems Co.
    Inventors: Larry W. Chamberlain, Clarence M. Brown, Jr.
  • Patent number: 4904132
    Abstract: In an indicator for visually displaying extremely small displacements between two points within a structure, a change of color visible through an indicator window occurs during a preselected portion of a predetermined displacement within the structure. The color change occurs due to an increase in thickness of a light-absorbing fluid in the central area of a clear, flexible indicator means separating a colored portion from the indicator window. Substantially no light-absorbing fluid is permitted to enter the central area until a preselected displacement has occurred since the colored portion is firmly, resiliently biased against the indicator window until that amount of displacement has occurred. Thereafter, light-absorbing fluid is permitted to enter the central area. This device concentrates visual indications of displacements into limited segments of an overall displacement.
    Type: Grant
    Filed: March 9, 1989
    Date of Patent: February 27, 1990
    Inventor: Charles H. Popenoe
  • Patent number: 4703711
    Abstract: The device consists of first and second load-receiving members, a breakable member and a part-spherical washer received in a seat in the second load-receiving member. In use, a load is applied by way of a rod or bar passing centrally through the load-receiving members and the breakable member positioned therebetween, the rod or bar also passing through a central bore in the washer and being angularly movable because of the support provided by the seat. When a predetermined load is achieved, annular cutting surfaces on the load-receiving member cut the breakable member with a predominantly shear action to indicate that the load has been achieved. Fractured parts of fingers of the bearing member are retained between surfaces to be visible at the periphery of the device.
    Type: Grant
    Filed: January 24, 1986
    Date of Patent: November 3, 1987
    Assignee: The Clay Cross Company Limited
    Inventor: John M. Haynes
  • Patent number: 4685337
    Abstract: A device for gauging hoop stress in a female threaded connector member, the stress being caused by tightening of a tapered male threaded member into the female member, including an annular body dimensioned for surrounding the female member with a firm fit therebetween, the body including two discrete complementary half-sections. Each of the half-sections includes an overlapping segment on one end, and each segment has an aperture therein. A pin is provided for insertion through the aligned apertures. An anchor block is fixed to each of the otherwise free ends of the annular body, each of the blocks having a cutout portion therein. A weak link having a tensile strength less than that of the annular body is provided for insertion into the cutout portions for joining the blocks. The weak link clamps the body about the female member and breaks under the application of a predetermined hoop stress to the female member.
    Type: Grant
    Filed: February 24, 1986
    Date of Patent: August 11, 1987
    Inventor: Kristy L. Church
  • Patent number: 4481902
    Abstract: Overlapping connections of sheet metal members in structural components are ested for cracks or flaws which are primarily the result of wear and tear under operating load conditions. For this purpose a test hole is made into or through the overlapping sheet metal members whereby each sheet metal member is provided with its own test hole portion. As long as the connection is still in good condition, adjacent test hole portions remain in register with each other. A sensor is inserted into the test hole. The sensor provides an indication of a faulty connection when the test hole portions are no longer in register. Several different types of sensors may be employed. The monitoring of the test holes and/or sensors may be made in a manual or automatic manner.
    Type: Grant
    Filed: March 17, 1982
    Date of Patent: November 13, 1984
    Assignee: Messerschmitt-Boelkow-Blohm Gesellschaft mit beschraenkter Haftung
    Inventors: Jochen Meyer, Richard Wilde
  • Patent number: 4457251
    Abstract: Apparatus to indicate the load on a restraining device subject to tensile loading, especially for a safety belt, the restraining device having an opening for communication with a restraining element, such as a seat belt, and being formed of two parts having different tensile strengths. The parts are displaceable with respect to each other upon loading of the restraining device in tension above a predetermined amount and one of the parts is provided with an indicator sign which becomes visible upon such displacement.
    Type: Grant
    Filed: March 2, 1979
    Date of Patent: July 3, 1984
    Assignee: N. V. Klippan S.A.
    Inventors: Per O. Weman, Fred F. Neumann
  • Patent number: 4424509
    Abstract: A sensor arrangement which is adapted to be triggered by deceleration forces. The sensor arrangement forms a component of a vehicle safety belt system and includes a mass deflectable from an initial position to a deflected position upon exceeding a predetermined deceleration and an indicator which responds if the belt of the safety belt system has been deployed during the occurrence of the predetermined deceleration. The mass is associated with the indicator and has such a mounting and/or includes a track of such an ascending slope, that the full deflection of the mass is attained only beginning at a deceleration of about 2 g. An arrangement is provided for preventing the deflected mass from returning to the initial position.
    Type: Grant
    Filed: June 1, 1981
    Date of Patent: January 3, 1984
    Assignee: Daimler-Benz Aktiengesellschaft
    Inventors: Rudolf Andres, Holger Seel
  • Patent number: 4348907
    Abstract: Apparatus for permanent affixure to a drilling mast raising line for indicating the condition of the mast raising line at selected intervals. Monitor sleeves are swaged to the mast raising line at a specified separation distance X when the line is new, and thereafter repeated measurements of the separation distance can be made to determine an approach to the elastic limits of the line whereupon the mast raising line should be retired from service.
    Type: Grant
    Filed: March 3, 1980
    Date of Patent: September 14, 1982
    Inventor: Gene E. Giese
  • Patent number: 4299185
    Abstract: Apparatus for activation of a chemical lightstick by downward sag of a mine roof is described. Through a spool and collar at the mine roof, two wires are extended from an anchor set in a stable formation above the roof, and are tied to a lightstick below the collar and spool. Pathways for passage of the two wires through the spool are provided so the wires are outside a center opening in the spool but are inside the outermost diameter of the neck of the spool. A spring-loaded embodiment permits the apparatus to tolerate a measured sag without activating the lightstick.
    Type: Grant
    Filed: November 21, 1979
    Date of Patent: November 10, 1981
    Assignee: American Cyanamid Company
    Inventors: William R. Heffernan, Mary-Louise Vega, Joel A. Gingras, Sr.
  • Patent number: 4249474
    Abstract: A sling has an indicator device which automatically registers the maximum permissible load which can be carried in accordance with the instantaneous angle of inclination of the strands of the sling.
    Type: Grant
    Filed: April 11, 1979
    Date of Patent: February 10, 1981
    Assignee: STAS Societe Technique d'Accessoires Specialises
    Inventor: Jean F. Archer
  • Patent number: 4245652
    Abstract: A relatively permanent barrier device which serves as a barrier to migration of foreign substances, as for example, bacteria or other disease promoting agents, through an opening in living animal tissue. The barrier device also aids in promoting healing of the animal tissue around the opening. In a preferred embodiment, the opening is designed to receive a percutaneous member or similar member for relatively permanent implant in the animal. Generally, the percutaneous member includes a stem which is insertable through the opening and into the subcutaneous facia of the animal with an enlarged head capable of overlying and engaging a portion of the barrier element. This member includes a fastening element shiftable into engagement with a portion of the animal tissue to retentively hold the member in the animal.
    Type: Grant
    Filed: October 10, 1978
    Date of Patent: January 20, 1981
    Assignee: Hamelly International, Inc.
    Inventors: Leonard T. Kelly, Esther V. M. Hamel
  • Patent number: 4182189
    Abstract: A method for attaining a predetermined compressive stress is achieved by a device in the form of a washer, coating, or plug which as a function of pressure does not yield significantly, but when a predetermined pressure is reached, a sudden change in structure takes place which effects detonation of an explosive mixture which detonation is indicated by a sound, a puff of smoke, a change of appearance, a sudden release of heat, or an instantaneous increase in friction. The device includes a porous brittle body in which an explosive substance has been absorbed, and also preferably hard particles that aid in effecting detonation when the porous body goes through a physical change. The detonation can also join contact surfaces together, serve as an indication of desired prestress or torque applied to a fastener, to indicate a load limit, and the like.
    Type: Grant
    Filed: March 14, 1978
    Date of Patent: January 8, 1980
    Assignee: Bulten-Kanthal AB
    Inventors: Carl G. Dock, Nils G. Schrewelius
  • Patent number: 4170163
    Abstract: An indicator for sensing the degree of tension in a tensile member. An indicator element defined by a deformable elastomeric member is positioned within a translucent containment wall. Upon application of a tensile force to the tensile member the indicator element is caused to be compressed and expanded radially outwardly into contact with the containment wall. The degree of contact of the indicator element and the containment wall varies as a function of the amount of tension applied to the tensile member. As a consequence the appearance of the indicator element as viewed through the translucent containment wall will vary as a function of the tension applied to the tensile member.The invention also has application in compression systems. One particular application disclosed is an indicator for sensing the appropriate degree of compression as applied to glass curtain walls used in dry pressure glazing systems.
    Type: Grant
    Filed: July 27, 1977
    Date of Patent: October 9, 1979
    Assignee: Modulus Corporation
    Inventor: William J. Payne
  • Patent number: 4149539
    Abstract: A hemostatic device comprising, a catheter having an elongated elastic shaft, an inflatable balloon adjacent a distal end of the shaft, and a sidearm adjacent a proximal end of the catheter. The device has a traction member comprising a retaining portion to receive the catheter shaft and sidearm, with the retaining portion being connected to an object to maintain the catheter shaft under selected tension.
    Type: Grant
    Filed: August 3, 1977
    Date of Patent: April 17, 1979
    Assignee: The Kendall Company
    Inventor: James P. Cianci
  • Patent number: 4102295
    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.
    Type: Grant
    Filed: July 19, 1976
    Date of Patent: July 25, 1978
    Assignee: American Hoist & Derrick Company
    Inventors: Edward J. Crook, Jr., Charles R. Garrett
  • Patent number: 4098114
    Abstract: A recording sheet, especially useful for measuring pressures of 1 to 2,000 kg/cm.sup.2 with a high degree of accuracy, comprising a support, a recording layer thereon, and a protective layer of a transparent synthetic resin provided on top of the recording layer by extrusion coating, the recording layer containing microcapsules having a .delta./D ratio (as defined in the specification hereof) of about 1.5 .times. 10.sup.-3 to about 2.5 .times. 10.sup.-1.
    Type: Grant
    Filed: March 28, 1977
    Date of Patent: July 4, 1978
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Yasuzi Asao, Yasuhiro Ogata, Noriyuki Hosoi
  • Patent number: 4090399
    Abstract: A load measuring gage generally shaped like a conventional split ring washer. In the center opening of the gage a shaft, which mounts the device whose load is to be measured, may extend through the washer. The opening for the washer is cut diagonally so that the loading and unloading forces acting upon it are collinear thereby reducing friction that resist its opening and closing to a minimum. This is accomplished by orienting the angle between the split ring surface and adjacent bearing surface to be between 50.degree. and 62.degree.. A force indicating pointer and scale can be attached to the washer to inform observers visually of variations in the force applied to the gage. In this way if the tension on a mine rock bolt is being measured, observers may safely be informed of the force on the in situ bolt from a distance.
    Type: Grant
    Filed: July 31, 1974
    Date of Patent: May 23, 1978
    Assignee: The United States of America as represented by the Secretary of the Interior
    Inventor: Clarence O. Babcock
  • Patent number: 4041776
    Abstract: An optical indicator of the type wherein the lessening of the load on a member under strain produces movement of an indicator element. Such movement takes place when the relaxation of the member under strain has reached a certain predetermined value thereby giving an immediate visual indication of that fact.
    Type: Grant
    Filed: March 22, 1976
    Date of Patent: August 16, 1977
    Assignee: Modulus Corporation
    Inventor: William J. Payne
  • Patent number: 4015465
    Abstract: A method and apparatus for determining fatigue in a structural part. The fatigue sensor comprises, for example, a thin silver zinc film affixed to a structural member that is to be monitored for fatigue damage. Upon sufficient flexing or other cold working, the silver zinc film undergoes a color change, pink to silver, to thereby indicate that the structural member has reached predetermined fatigue levels.
    Type: Grant
    Filed: March 31, 1975
    Date of Patent: April 5, 1977
    Inventor: William R. Scott
  • Patent number: 3987699
    Abstract: An indicator for optically indicating small displacements or changes in displacement of one member relative to another member, comprising a self-contained container encapsulating a light absorbing indicator fluid, a window in the container for viewing the indicator fluid, an opposite wall portion, and a flexible portion in between the window portion and the wall portion, allowing relative movement therebetween so that an external member, fixed to one of the portions may deform the container and change the thickness of the fluid seen through the window in response to changes in displacement between the first two members.
    Type: Grant
    Filed: November 14, 1974
    Date of Patent: October 26, 1976
    Inventor: Charles H. Popenoe
  • Patent number: 3987668
    Abstract: An indicator for optically indicating small displacements or changes in displacement of one member relative to another member, comprising a light transmitting member having a faceted light reflective under surface, and an opaque, light absorbing member disposed beneath the light transmitting member, whereby when the two members are separated by a thin film of air, incident light transmitted through the transmitting member is totally internally reflected at the under surface displaying a bright appearance to an observer. When the two members are forced into intimate contact by a displacement to be indicated, the incident light is absorbed by the second member and a dark appearance is presented to an observer.
    Type: Grant
    Filed: November 17, 1975
    Date of Patent: October 26, 1976
    Inventor: Charles H. Popenoe
  • Patent number: 3964299
    Abstract: A strain indicator of the type wherein a change in length of a strain member produces a change in color of a visual indicator. An indicator area and a light-absorbing indicator fluid are encapsulated in a member that also includes a window. The capsule is fastened to the strain member with an adhesive. A change in length of the strain member causes the indicator area to become separated from the window with the result that light-absorbing indicator fluid is caused to flow between the indicator area and the window.
    Type: Grant
    Filed: June 20, 1974
    Date of Patent: June 22, 1976
    Assignee: Modulus Corporation
    Inventor: Robert Carol Johnson
  • Patent number: 3948141
    Abstract: A load-indicating washer for use in joining two different elements which is capable of visually indicating the tightening force applied against a locking bolt and nut through the indication of encapsulated fluid released under the tightening load. The encapsulated fluid being provided in a depression formed in at least one bearing surface of the washer.
    Type: Grant
    Filed: August 20, 1974
    Date of Patent: April 6, 1976
    Inventor: Katsumi Shinjo