GB2119524A - Process and apparatus for measuring the tensile stress in a rivet of a riveted joint - Google Patents
Process and apparatus for measuring the tensile stress in a rivet of a riveted joint Download PDFInfo
- Publication number
- GB2119524A GB2119524A GB08212191A GB8212191A GB2119524A GB 2119524 A GB2119524 A GB 2119524A GB 08212191 A GB08212191 A GB 08212191A GB 8212191 A GB8212191 A GB 8212191A GB 2119524 A GB2119524 A GB 2119524A
- Authority
- GB
- United Kingdom
- Prior art keywords
- another
- pieces
- rivet
- stop member
- pressure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims abstract description 20
- 238000003475 lamination Methods 0.000 claims abstract description 7
- 238000006073 displacement reaction Methods 0.000 claims description 9
- 238000012360 testing method Methods 0.000 claims description 7
- 230000001066 destructive effect Effects 0.000 claims description 5
- 230000005489 elastic deformation Effects 0.000 claims description 5
- 230000006835 compression Effects 0.000 claims description 4
- 238000007906 compression Methods 0.000 claims description 4
- 238000013459 approach Methods 0.000 claims description 2
- 229910000831 Steel Inorganic materials 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 238000013519 translation Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
- Insertion Pins And Rivets (AREA)
Abstract
The process of a rivet 5 joining components together, e.g., components 2, 4 of the cage 1 for roller bearings together is determined by placing the joint between a fixed member 10 and a movable member 11, moving member 11 towards member 10 to elastically compress with a predetermined force the components 2, 4 and measuring the change in length of the rivet as a result of the deformation of components 2, 4. Resilient laminations 18 provided on gauge 16 bear against the opposite ends of rivet 5 and the deformation of laminations 18 as a result of change in length of rivet 5 is detected by electric transducer strain gauges 19. <IMAGE>
Description
SPECIFICATION
Process and apparatus for measuring the coaction tensile stress in riveted joints
The present invention relates to a process and relevant apparatus for measuring the coaction tensile stress in riveted joints, with particular reference to the riveted joints of cages of straight roller bearings of large dimensions used in railway systems.
In the straight roller bearings of large dimensions, a widely used configuration of the roller guiding cage is that in which the junction is obtained by riveting a ring of rectangular crosssection, referred to as washer, to another ring, referred to as "tenon ring", rigidly connected to as many tenons as are the rollers between which they are interposed. Thus a thick cylindrical zone is created which has openings in the which the rollers are free to rotate.
In the past, the sturdiness and hence the life of the cage was not affected by the stresses which are originated by modern rotation speeds, and the bearing reached the end of its life as result of the wear of the steel which its parts are made of. In fact, the materials and the working were not at such high quality and design levels as they are at present time. In the last years, instead, the straight roller bearings, better constructed, but subjected to higher stresses, are finding their own limit in the cage, namely because of loosenings and subsequent breakings of the rivets which, passing into the interior of the tenons ensure the junction of the washer with the tenon ring.Since it is a question of fatigue breakings, which prelude a rapid seizure of the bearing with consequent breaking of the mechanical members on which it is keyed, it is obviously very important for the rivets to have a mechanical pre-tension sufficient to always ensure a rigid frictional coupling between the said two parts forming the cage.
Hence the necessity of having the possibility to verify the mechanical pre-tension of the rivets by rapid and direct measuring both during the manufacturing and at the maintenance operations on the bearings. To-day, this verification is impossible for the bearings being used, and in many manufacturing firms the control is carried out at very long intervals, by indirect methods and destroying the piece under examination; thus, the desired measuring is carried out by a destructive, little reliable and little precise process.
The object of the present invention is to provide a process and relevant apparatus for carrying out non-destructive controls of riveted joints, which process and apparatus will indicate with precision the reaction tensile stresses to which the rivets are subjected.
This object is attained by the present invention which relates to a process for measuring the mechanical tension of a rivet connecting to one another at least two pieces facing one another, characterized in comprising the following stages:
positioning one of the two pieces against a stop member and positioning a pressure member, disposed in face of said stop member, against the other of said two pieces, so that said pressure member and said stop member may approach one another;
approaching said stop member and said pressure member to one another so as to compress said two pieces against one another with a pre-established force in order to produce in them an elastic deformation; and
measuring the length variation of said rivet as a result of the compression stress induced into said two pieces by the mutual approaching of said stop member and said pressure member.
The invention relates also to an equipment for carrying out non destructive quality tests on two pieces riveted to one another, characterized in comprising:
a stop member and a pressure member disposed in face of one another and movable towards one another, between said stop member and said pressure member there being formed a space arranged to accommodate said two pieces which are joined to one another by at least one rivet;
motor means for approaching, with a predetermined force, said stop member and said pressure member to one another so as to compress between them, with a predetermined pressure, said two riveted pieces; and
measuring means for detecting the variations of the length of said rivet.
For a better understanding of the present invention, an embodiment thereof will now be described, by way of non limiting example, with reference to the annexed drawing which diagrammatically shows a test equipment according to the teachings of the present invention for testing the cages of bearings.
In the drawing, reference numeral 1 indicates a cage for bearings, in the present case a cage for roller bearings (not shown) of large dimensions for use in railway systems, comprising two pieces formed by a tenon ring 2, provided with a plurality of tenons 3, and a washer 4, made preferably of copper and joined to one another by a plurality of steel rivets 5 provided with riveted opposed end heads 6 and 7, respectively, housed within tenons 3. Thus, the cage 1 has a plurality of windows 8 in which rollers (not shown) of said bearing may be lodged, and the pieces 2 and 4 are angularly connected to one another by frictional coupling, inasmuch as the rivets 5 have been put under tension by means of a pre-tension and therefore they maintain the pieces 2 and 4 elastically compressed against one another.
The cage 1 results in being mounted on an apparatus 9 for carrying out a non destructive quality test on at least two pieces of any kind, facing one another and mutually joined by at least a rivet. In particular, the apparatus 9 is apt to detect the mechanical tensile stress, or pretension, to which the rivet 5 is subjected. It is clear that the equipment 9, as will be described in detail later, may be used indifferently for carrying out measurements on the cage 1 or on any other riveted connection.
The apparatus 9 comprises a stationary stop member 10, formed by a plate, and a movable pressure member 11 disposed in face of the member 10 and movable towards this latter as a result of the actuation of actuator and/or motor means 12, formed for example by an air cylinder a hydraulic cylinder, an electric motor or any other device arranged to linearly move the member 11, by a predetermined force, against the member 10.
These latter define between them a seating 13 in which the pieces 2 and 4 are disposed, so that these latter are compressed to one another and against the element 10 as a result of the advancement of the element 11 with an adjustable and predeterminable pressure, by acting onto the motor means 12.
In addition, the apparatus 9 is provided with a support element 14 for the cage 1 and with measuring means 15 comprising a gauge 16 provided with two tracers having resilient laminations 1 8 facing one another, arranged to cooperate with the heads 6 and 7 of the rivet 5 to detect their mutual displacements so as to substantially measure the variation of the length of the rivet 5 due to the elastic compression of the pieces 2 and 4 against one another. The means 1 5 comprise also transducer means 19 formed for example by four electrical straingauges arranged to detect the elastic deformations of the laminations 18 originated by the displacements of the heads 6 and 7.The elements 10 and 11, in the embodiment shown, are annular and are provided each with a plurality of seatings 20 for housing the tracers 18 and allowing their free movement and their cooperation with the heads 6 and 7. In a variant not shown, the apparatus 9 is provided also with second measuring means formed by a second gauge similar to the gauge 16, arranged to cooperate with surfaces 21 and 22 of the pieces 2 and 4 in order to measure their relative displacement in the direction of the axis of the rivet 5, and by electronic comparator means, connected both to the straingauges 19 and to transducer means of said second gauge in order to compare the displacement of the surfaces 21 and 22 with the variation of the length of the rivet 5.
The apparatus 9, by means of which the process for measuring the tension of the rivet 5 which connects the pieces 2 and 4 is implemented, operates as follows.
At first, cage 1 is positioned between the elements 10 and 11 so that these latter, when approaching one another, may compress the pieces 2 and 4 against one another, thus slackening the tension in the rivet 5, and at the same time the gauge 16 is positioned so as to make the tracers 18 cooperate with the heads 6 and 7 of the rivet of which it is desired to measure the tension. Then, by starting the motor means 12 the element 11 is moved towards the element 10 thus compressing to one another the pieces 2 and 4 which thus deform elastically and shorten along the axis of the rivet 5. This latter, which owing to the pre-tension results in being under tension and elastically deformed by tensile stress, may compensate the elastic deformation by reducing
its own length.However, the variation of the
length of the rivet 5 is detected by the tracers 18 and transmitted by the transducers 1 9 to suitable known indicator means (not shown).
Thus, the process proposed by the present invention and implementable by means of the apparatus 9 described hereinabove consists in compressing the pieces 2 and 4 against one another in the region of single tenons 3, so as to give rise to an elastic compression of the same and allow the rivet 5 to freely shorten until the whole elastic deformation due to the pre-tension is fully compensated.By measuring this shortening, arid as the modulus of elasticity (E) of the steel and the section (S) of the rivet, as well as its length, are known, the value of the pre-tension is obtained by the known and simple formula:
dlxExS P= 1 where dl is the length variation detected by the sensors 1 5. Obviously, the four straingauges 19 applied to the laminations 18 are suitably equilibrated so that they are insensitive to any movement of the rivet 5 during the movement of the elements 10 and 11, except the variation of the length of rivet 5.
A configuration like that described hereinabove allows to detect the values of the total tensile stress for each rivet 5 of the cage 1 or to simply verify whether such value is higher than a determined minimum by choosing, through simple calculations, suitabie values of the pressure force p to be exerted in the region of the tenon 3.
By adding another measuring transducer on the cage 1 in accordance with said variant not shown, it is possible to measure in the same manner the idle stroke of the element 11 and, hence, the values of the clearances, if any, between the washer 4 and the tenon ring 2.
An advantageous configuration for controlling all tenons simultaneously, in case large quantities of bearings have to be controlled, may be obtained by widening the configuration just described; a pressure crown may be made to act on the entire cage 1, said crown being provided with a plurality of seatings 20 for the passage of a plurality of gauges 1 6 in number to that of the tenons 3. These will be provided, within the apparatus 9, with radial translation members which will allow to position them on the cage 1 simultaneously.An electronic processor circuit of an well known type and with a completely obvious procedure, in addition to controlling the successive operations, may scan the rivets one at a time or even many of them simultaneously, only indicating the maximum and minimum values among them which are detected and emitting an alarm signal in case of the controlled piece being unacceptable.
Thus, with the process according to the present invention the piece being controlled is not destroyed, so that it is possible to carry out not only a control of samples only, but also a hundred percent control, for the pieces being produced, as well as for those to be re-utilized, during revision.
Moreover, the system according to the present invention is simple, reliable, economical and of extreme precision.
Finally, from the foregoing it is clear that modifications and variations may be made to the process and relevant apparatus according to the present invention, without departing from the scope of the invention itself. In particular, it is possible to utilize measuring devices of other types, different from the straingauges.
Claims (10)
1. A process for measuring the mechanical tension of a rivet connecting to one another at least two pieces disposed in face of one another, characterized in comprising the following stages:
positioning one of the two pieces against a stop member and positioning a pressure member, disposed in face of said stop member, against the other of said two pieces, so that pressure member and said stop member may approach one another;
approaching said stop member and said pressure member to one another so as to compress said two pieces against one another with a predetermined force in order to produce in them an elastic deformation; and
measuring the variation of the length of said rivet as a result of the compression stress induced into said two pieces by the mutual approaching of said stop member and said pressure member.
2. A process as claimed in Claim 1, characterized in that said stop member is stationary and said pressure element is movable towards said stop member and cooperates with actuator means to push, with a predeterminable pressure, the said pressure member against the said two pieces disposed in face of one another, and consequently these latter against said stop member.
3. A process as claimed in Claim 1 or 2, characterized in that said measuring stage is carried out with the aid of measuring means arranged to cooperate with opposite heads of said rivet in order to detect their mutual displacements.
4. A process as claimed in Claim 3, characterized in that the said measuring means comprise tracers which, during said positioning stage, are brought into contact with said heads and thus are maintained in contact with these latter during said successive stages, and transducer means arranged to measure the displacement of said tracers.
5. A process as claimed in any of the preceding
Claims, in which the said two pieces are formed by a tenon ring and by a washer of a cage for roller bearings, connected to one another by a plurality of rivets, characterized in that the said stop member and the said pressure member are annular in shape, measuring means being provided in the region of each of said rivets.
6. An apparatus for carrying out nondestructive quality tests on two pieces riveted to one another, characterized in comprising:
a stop member and a pressure member disposed in face of one another and movable towards one another, between said stop member and said pressure member there being formed a space arranged to accommodate said two pieces which are jointed to one another by at least a rivet;
motor means for approaching, with a predetermined force, said stop member and said pressure to one another so as to compress between them, with a predetermined pressure, said two riveted pieces; and
measuring means for detecting the variations of the length of said rivet.
7. An apparatus as claimed in Claim 6, for carrying out tests on cages of roller bearings
intended for use in railway systems, characterized in that the said stop member and the said
pressure member are annular in shape and have each a plurality of seatings for accommodating said
measuring means.
8. An apparatus as claimed in Claim 6 or 7,
characterized in that the said measuring means
comprise a gauge provided with two elastic
laminations disposed in face of one another and
arranged to cooperate with opposite end heads of
said rivet in order to follow their movements, and
a plurality of straingauges disposed on the said
laminations and apt to detect the deformations of
these latter as a result of the displacement of said
heads.
9. An apparatus as claimed in any of the
Claims from 6 to 8, characterized in comprising
also second measuring means for detecting the
mutual displacement of surfaces of said two
riveted pieces, and comparator means for
comparing said displacement with the variation of
the length of said rivet.
10. An apparatus for carrying out non
destructive quality tests on at least two pieces
riveted to one another, characterized in
comprising means for implementing a process as
claimed in any of the Claims from 1 to 5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08212191A GB2119524B (en) | 1982-04-27 | 1982-04-27 | Process and apparatus for measuring the tensile stress in a rivet of a riveted joint |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08212191A GB2119524B (en) | 1982-04-27 | 1982-04-27 | Process and apparatus for measuring the tensile stress in a rivet of a riveted joint |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2119524A true GB2119524A (en) | 1983-11-16 |
| GB2119524B GB2119524B (en) | 1986-05-29 |
Family
ID=10530007
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08212191A Expired GB2119524B (en) | 1982-04-27 | 1982-04-27 | Process and apparatus for measuring the tensile stress in a rivet of a riveted joint |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2119524B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112461519A (en) * | 2020-11-12 | 2021-03-09 | 合肥工业大学 | Bidirectional rivet checking mechanism |
| CN114034474A (en) * | 2021-10-09 | 2022-02-11 | 中国直升机设计研究所 | Device and method for testing riveting pressure and nail hole pressure of solid rivet |
| CN114636619A (en) * | 2022-05-19 | 2022-06-17 | 歌尔股份有限公司 | Test fixture and riveting force test equipment |
| CN115121758A (en) * | 2022-06-24 | 2022-09-30 | 佛吉亚(盐城)汽车部件系统有限公司 | Riveting device with triangular force-increasing mechanism and riveting system comprising same |
-
1982
- 1982-04-27 GB GB08212191A patent/GB2119524B/en not_active Expired
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112461519A (en) * | 2020-11-12 | 2021-03-09 | 合肥工业大学 | Bidirectional rivet checking mechanism |
| CN112461519B (en) * | 2020-11-12 | 2022-07-22 | 合肥工业大学 | Bidirectional rivet checking mechanism |
| CN114034474A (en) * | 2021-10-09 | 2022-02-11 | 中国直升机设计研究所 | Device and method for testing riveting pressure and nail hole pressure of solid rivet |
| CN114034474B (en) * | 2021-10-09 | 2023-06-06 | 中国直升机设计研究所 | Solid rivet riveting pressure and nail hole pressure testing device and method |
| CN114636619A (en) * | 2022-05-19 | 2022-06-17 | 歌尔股份有限公司 | Test fixture and riveting force test equipment |
| CN115121758A (en) * | 2022-06-24 | 2022-09-30 | 佛吉亚(盐城)汽车部件系统有限公司 | Riveting device with triangular force-increasing mechanism and riveting system comprising same |
| CN115121758B (en) * | 2022-06-24 | 2024-02-02 | 佛吉亚(盐城)汽车部件系统有限公司 | Riveting device with triangular force increasing mechanism and riveting system comprising same |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2119524B (en) | 1986-05-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |