US3776031A

US3776031A - Tensile member with tension indicator

Info

Publication number: US3776031A
Application number: US00172019A
Authority: US
Inventors: J Trigg
Original assignee: INT ENG CONCESSIONARIES Ltd
Current assignee: INT ENG CONCESSIONARIES Ltd
Priority date: 1970-08-19
Filing date: 1971-08-16
Publication date: 1973-12-04
Anticipated expiration: 1990-12-04
Also published as: DE2141658A1; FR2104554A5; AU3251371A; GB1352327A; CA945833A; NL7111406A; ZA715435B; BE771426A

Abstract

A tensile member adapted to indicate the tension on it has a pin reciprocable in a bore in the tensile member the bottom of which constitutes a stop for the pin. A disc spring is coupled to the pin. The disc spring is urged into contact with a surface of the tensile member surrounding the entrance to the bore when the pin is pressed into the bore. The disc spring becomes distorted and snaps through when the distance between the bottom of the bore and the entrance of the bore increases by a given amount as a result of elongation of the tensile member caused by tensioning it.

Description

United States Patent 1 1111 3,776,031

Tngg Dee/4, 1973 [54] TENSILE MEMBER WITH TENSION 2,434,984 1/1943 Bolesky et al. 73/373.3 x INDICATOR 1 2,850,937 9/1958 Ralston 85/62 3,539,234 6/1971 Trigg 85/62 Inventor: 4 J Victor g gg, Odiham, 3,243,923 5/1966 131a1 616 73/33 F England 3,561,260 2/1971 Reynolds.... 73/33 F 2,995,033 8/1961 Stifano 73/33 F [73] Assignee: International Engineering Concusionaries Limited,

waltomonqhames Surrey, Primary Examiner-Richard C. Q ueisser England 1 Assistant Examiner-Arthur E. Karkosz AttorneyWoodhams, Blanchard & Flynn [22] Filed: Aug. 16, 1971 [21] A p]. N01: 172,019 57 AB RA T v I A tensile member adapted to indicate the tension on. it 7 Foreign Application Priority Data has a pin reciprocable in a bore in the tensile member Aug. 19, 1970 Great Britain 39,995 the bottom of which constitutes a p for the P h disc spring is coupled to the pin. The disc spring is 52 US. Cl. 73 95, /62 utgedinto Contact with a Surface of the tensile [51] Int, Cl. G01n 3/08 her Surrounding the entrance to thebore when the P 53 Field of Search 73/88 F, 85/62, is Ptessed into the bote- The disc Spring becomes 35 1 32 T 1 T torted and snaps through when the distance between the bottom of the bore and the entrance of the bore 5 I Reta-"Ices Cited increases by a given amount as a result of elongation UNITED, STATES PATENTS of the tensile member caused by tensioning it. 1,767,709 6/1930 Smith 713/3783 I 8 Claims, 5 Drawing Figures .4 D b 16 Z 5 5 1 TENSILE -MEMBER WITH TENSION INDICATOR The present invention relates to a tensile member provided with a tension indicator and provides a tensile member having a member moveable relative thereto and towards a stop for the moveable member fixedrelative to a region of the tensile member, and a bi-stable resilient member arranged to be urged by the moveable member to bear against a surface of the tensile member remote from the said region when the moveable member is urged towards the stop, whereby the resilient member becomes distorted, and thereby snaps through from one stable configuration to anotherwhen the distance between the said region and the said surface increases by a given amount as a result of elongation of the tensile member caused by tensioning thereof.

With this arrangement, the resilient member and moveable member can be so set that when the desired tension is reached, the moveable member can be displaced relative to the said surface sufficiently to distort the resilient member as it bears against the said surface to apoint at which it snaps through. In use, pressure can be applied to urge the moveable member towards the stop and the tensile member can be progressively tensioned. An audible click as the resilient member snaps through indicates that the desired tensioning has been reached.

Advantageously, means are provided for resiliently resisting movement of the moveable member towards the stop, and a shoulder is provided on the tensile member spaced from and facing towards the said surface, th moveable member, when movingaway from the stop, pressing the resilient member against the shoulder, whereby when the resilient member has snapped through it will snap back to its original resilience and configuration when pressure on the moveable member is relaxed. This arrangement maintains the resilient member normally in its original resilience and configuration, whereby testing of the tensile member in use, by pressing the moveable member towards the stop, is facilitated, and permits use of the tensile member under water. The tactile sensation as the resilient member reached.

Usually, the resilient member is kept spaced from the said surface on the tensile member, except when testing or setting is taking place.

The present invention will now be more fully described with the aid of examples illustrated in the accompanying drawings in which:

FIG. 1 shows in section a tensile member in accordance with the invention together with a tool for testing the tensile member;

FIG. 2 shows in section a portion of the tensile member of FIG. 1 before setting;

FIGS. 3 and 4 show in section further forms of tensile members in accordance with the invention; and

FIG. 5 shows in section a portion of the upper end of the tensile member of FIG. 3 of 4 in the course of assembly.

same reference numberals. Referring to the drawings a tensile member 1 has a bore 2 therein and a pin 3 which is a sliding fit in the bore. The bottom of the bore 2 constitutes a stop limiting movement of the pin 3 in the bore. When the pin 3 is displaced towards the bottom of the bore 2 a bistable disc spring 4, of the sort known as a Belleville washer, is urged by the pin against a surface 6 on the tensile member 1 and is thus distorted. The disc spring 4 may be in the formof a plain disc or may have radially extending slots extending either outwardly from the central aperture orinwardly from the circumference. The spring 4 is carried on the pin 3 between op-' posing shoulders formed by a circumferential groove 7, and is normally spaced from the surface 6. When the tensile member 1 is un-stressed,the stop constituted by the bottom of the bore 2prevents the pin 3 from being displaced sufficiently todistort the disc spring 4 to the point at which the disc spring can snap through. However, when tension is applied to the tensile member 1, the member elongates and the distance between the bottom of the bore2 and the surface 6 increases, permitting the pin 3 to be displaced further into the bore. The disc spring 4 and pin 3 are so set that when the desired tension is reached the displacement of the pin 3 then possible is sufiicient to distort the spring 4 to a point at which the spring snapsthrough, to the configuration shown in broken lines in FIG. 1. When the spring 4 snaps through it gives an audible click, providing an indication that the desired tension has been reached.

In the examples shown in the drawings a compression spring 8 in the bottom of the bore 2 resiliently resists movement of the pin towards the bottom of the bore,

and returns the pin 3 when pressure onthe pin is re laxed. A flexible button 9, conveniently of plastics or metal, and which is a force fit in an aperture in the ten sile member has an annular shoulder on the surface facing towards the surface 6, against which the pin 3, when returned by the action of the spring 8, presses the disc 'spring 4, whereby the disc spring snaps through to its original resilience and configuration.

In manufacture of the tensile member shown in FIG. 1, the pin 3 is initially provided with a cylindrical end portion shown at 12 in FIG. 2. The end portion 12 is made relatively soft compared with the remainder of the pin, for example by conventional heat treatment, so as to be plastically deformable. With all the components illustrated assembled in the positions shown in the drawings, the tensile member is loaded to a predetermined tension corresponding to the load which it is desired to maintain in use, and pressure greater than that which can be exerted directly by hand is applied gradually to the pin 3, to cause plastic deformation of the plastically deformable end portion 12 into the configuration shown in FIGS. 1 and 3 thus permitting displacement of the pin towards the bottom of the bore 2, until the disc spring4 just snaps through, and the pressure on the pin is then relaxed.

The use in setting of pressure greater than that which can be exerted by hand ensures that the softened end portion 12 of the pin 3 will not be deformed accidentally in use of the tensile member when hand pressure is applied to the pin to test that the desired tension in the tensile member is maintained.

In the examples shown in FIGS. 3 and 4 the pin 3 that exertable byhand is used to press the pin 3 into the bore with sufficient force to dislodge the scroll-pin 22 and push it deeper into the tube 21. In use, when hand pressure is exerted on the pin 3, the scroll-pin 22 cannot be dislodged and its engagement with the bottom of the bore 2 limits movement of the pin 3.

As shown in FIG. 5, the disc spring 4 and pin 3 of the tensile member of FIGS. 3 and 4 can be assembled by initially forming the tube-form pin 3 to taper towards its end so that the spring 4 can be easily fed onto the end of the pin 3 until its apertured middle coincides with the groove 7, whereafter the end of the pin 3 is spun outwards to secure the disc spring 4 in the groove 7.

In order to improve sensitivity in testing, the testing pressure can be applied with a spring-loaded pointed tool 13 illustrated in FIG. 1 which is mounted in a holder 14 with a spring 16 which has a spring rate similar to the spring 8, and which will not become solid before the disc spring 4 snaps through. A dimple can be provided in the outer surface of the button 9 to locate the point of the tool, and the button 9 may be located on the head of the pin 3 by a projection 17 in FIG. 1 which engages a transverse slot 18 in the pin 3.

In the forms shown in FIGS. 3 and 4 the button 9 is located on the pin 3 bya projection 23 which engages and is a tight fit in the tube 21 constituting the upper end of the pin 3. The form of button 9 illustrated in FIG. 3, having concentric grooves in its upper surface is preferred to that of FIG. 4 since it has no undercut portions and is thus easier to produce by conventional plastics-material forming techniques whilst having sufficient flexibility in use. It is contemplated that the resilient properties of the button 9 may be employed instead of the spring 8 for resiliently resisting movement of the pin 3.

Although the arrangement shown in the drawings are preferred, other arrangements can be employed. In one modification, the stop is constituted by a volute spring press-fitted into the bottom region of the bore 2 and bearing on the bottom of the pin 3. In setting, pressure greater than that exertable directly by hand is used to press the pin into the bore with sufficient force to dislodge the volute spring and push the volute spring deeper into the bore. In use, when hand pressure is exerted on the pin, the volute spring cannot be dislodgedand forms a stop when the coils of the spring engage with one another and the spring becomes solid.

In a further modification, the pin is located in the bottom of the bore by a Mills pin seated in the bottom of the bore and arranged with its point facing away from the bottom of the bore and wedging in a hole in the pin tapering in the direction away from the bottom of the bore. The head of the first-mentioned pin constitutes a stop for the button which is mounted normally spaced from the head of the pin, and the surface of the button facing towards the surface 6 bears on the spring 4 when pressed towards the head of the pin. In setting, pressure greater than that exertable by hand is applied to the button to press the first-mentioned pin onto the Mills pin and to wedge the Mills pin progressively deeper in the hole in the pin.

I claim:

1. In combination: a tensile member having a stop fixed relative to a first region thereof, and means defining a reaction surface on said tensile member fixed relmeans including a movable member movable by,

hand pressure relative to said tensile member, means defining a shoulder spaced from and facing towards said reaction surface, and a bi-stable resilient member between said reaction surface and said shoulder and operatively coupled to said movable member, said bi-stable resilient member being resiliently deformable between first and second stable configurations, whereby when said movable member is urged in a first direction, said resilient member is urged towards said surface and becomes distorted and snaps through from said first stable configuration to said second stable configuration when the distance between said first region and said reaction surface increases by a given amount as a result ofelongation of said tensile member caused by tensioning thereof; and whereby said movable member when moving in a second direction opposite to said first direction presses said resilient member against said shoulder so that said resilient member snaps through from said second stable configuration to said first stable configuration. 2. The combination according to claim 1, wherein said tensile member has a' bore. therein, said movable member being movably positioned within said bore, the

bottom of said bore constituting said stop.

3. The combination according to. claim 2, in which the surface of the tensile member adjacent the entrance to said bore constitutes said reaction surface remote from said first region.

4. The combination according to claim 2, including a button mounted on said tensile member and located at the entrance of said bore outwardly from said movable member, said shoulder being provided on said button.

5. The combination according to claim 1, including means resiliently resisting movement of said movable member towards said stop.

6. The combination according to claim 1, wherein said bi-stable resilient member is a disc spring.

7. The combination according to claim 1, wherein said movable member is slidably supported in said tensile member for relative linear movement therebetween.

8. An indicator structure comprising: a first member having a reaction surface; means defining a shoulder spaced from and facing towards said reaction surface; a movable member movable by hand pressure relative to said surface; a bi-stable resilient member between said reaction surface and said shoulder and engaging and moving with said movable member, said bi-stable resilient member being movable between two stable I configurations whereby said movable member can be moved by hand pressure to urge said resilient member towards said reaction surface and snap said resilient member through from one stable configuration to another stable configuration; and resilient means which urge said movable member to move said resilient member towards said shoulder when hand pressure is released after said resilient member has snapped through to said another stable configuration, said, resilient means being stronger in action than said resilient member whereby said resilient member can distort against said shoulder and snap back to said one stable configuration.

Claims

1. In combination: a tensile member having a stop fixed relative to a first region thereof, and means defining a reaction surface on said tensile member fixed relative to a second region of said tensile member remote from said first region; and indicator means for determining whether a desired tension exists in said tensile member, said indicator means including a movable member movable by hand pressure relative to said tensile member, means defining a shoulder spaced from and facing towards said reaction surface, and a bi-stable resilient member betwEen said reaction surface and said shoulder and operatively coupled to said movable member, said bi-stable resilient member being resiliently deformable between first and second stable configurations, whereby when said movable member is urged in a first direction, said resilient member is urged towards said surface and becomes distorted and snaps through from said first stable configuration to said second stable configuration when the distance between said first region and said reaction surface increases by a given amount as a result of elongation of said tensile member caused by tensioning thereof; and whereby said movable member when moving in a second direction opposite to said first direction presses said resilient member against said shoulder so that said resilient member snaps through from said second stable configuration to said first stable configuration.

2. The combination according to claim 1, wherein said tensile member has a bore therein, said movable member being movably positioned within said bore, the bottom of said bore constituting said stop.

3. The combination according to claim 2, in which the surface of the tensile member adjacent the entrance to said bore constitutes said reaction surface remote from said first region.

8. An indicator structure comprising: a first member having a reaction surface; means defining a shoulder spaced from and facing towards said reaction surface; a movable member movable by hand pressure relative to said surface; a bi-stable resilient member between said reaction surface and said shoulder and engaging and moving with said movable member, said bi-stable resilient member being movable between two stable configurations whereby said movable member can be moved by hand pressure to urge said resilient member towards said reaction surface and snap said resilient member through from one stable configuration to another stable configuration; and resilient means which urge said movable member to move said resilient member towards said shoulder when hand pressure is released after said resilient member has snapped through to said another stable configuration, said resilient means being stronger in action than said resilient member whereby said resilient member can distort against said shoulder and snap back to said one stable configuration.