GB2263745A - "load indicating washer" - Google Patents
"load indicating washer" Download PDFInfo
- Publication number
- GB2263745A GB2263745A GB9301634A GB9301634A GB2263745A GB 2263745 A GB2263745 A GB 2263745A GB 9301634 A GB9301634 A GB 9301634A GB 9301634 A GB9301634 A GB 9301634A GB 2263745 A GB2263745 A GB 2263745A
- Authority
- GB
- United Kingdom
- Prior art keywords
- annular body
- protuberances
- indicating washer
- face
- load indicating
- 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.)
- Withdrawn
Links
- 238000007373 indentation Methods 0.000 claims abstract description 13
- 230000036316 preload Effects 0.000 claims description 44
- 230000015572 biosynthetic process Effects 0.000 abstract description 2
- 238000009434 installation Methods 0.000 description 3
- 241001430696 Protis Species 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B31/00—Screwed connections specially modified in view of tensile load; Break-bolts
- F16B31/02—Screwed connections specially modified in view of tensile load; Break-bolts for indicating the attainment of a particular tensile load or limiting tensile load
- F16B31/028—Screwed connections specially modified in view of tensile load; Break-bolts for indicating the attainment of a particular tensile load or limiting tensile load with a load-indicating washer or washer assembly
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Bolts, Nuts, And Washers (AREA)
Abstract
A load indicating washer (40) comprises protuberances (44), struck and partially sheared from the annular body (42) of the washer (40), are pressed under load in a bolted joint back into the corresponding indentations (48) formed in the annular body (42) by the formation of the protuberances (44), indicia (73) being provided in radial alignment with the spaces between the protuberances (44), so that a feeler gauge (not shown) can be inserted between the protuberances (44) to determine when the protuberances (44) have collapsed back into the indentations (48) a prescribed amount corresponding to the desired loading of the bolted joint. <IMAGE>
Description
DIRECT TENSION INDICATOR WASHER TBCHNICAL FIELD
The present invention relates, in general, to the installation of fasteners and, in particular, to a pre-load indicating washer for use with a fastener which enables the desired tension of the fastener to be achieved during installation of the fastener in a joint.
BACKGROUND OF THE INVENTION
It is well known to those skilled in the art that the most accurate way to install tension into fasteners in a joint is to control tightening by developing an indication of the tension in the fastener either directly from the fastener or another component used with the fastener. Fastener installation based on torque control can result in wide variations in the tension in the fastener because of variations in fastener lubricity, burrs on the thread of threaded fasteners, and variations in the friction at the surface of the joint component against which the bearing surface of a threaded fastener bears.
U.S. Pat. No. 3,187,621 and U.S Pat. No.
5,015,132 are directed to pre-load indicating washers adapted for use with a threaded fastener and intended to develop an indication of proper tensioning of the fastener. These pre-load indicating washers have a plurality of protuberances which are struck and partially sheared from an annular body to leave indentations in the annular body. With these pre-load indicating washers in a joint, the protuberances are pushed back into the indentations in the annular body as the joint is tightened and tightening is stopped when the protuberances have been "collapsed" back into the indentations in.the annular body a prescribed amount.
This condition, typically, is sensed by a "feeler" gage inserted into a gap in the joint.
It is important that the feeler gage be inserted into the space between two protuberances.
Because this space cannot be seen, it is found by feel which can be time-consuming. In addition, there is risk that the feeler gage has not been inserted into the space between two protuberances when it appears that this space has been found by feeling for it.
One attetnpt to overcome this problem has been to stamp marks into that face of the washer from which the protuberances project. Such an arrangement is not entirely satisfactory because the marks can be hidden from view by a bolt head or accompanying washer.
SUMMARY OF THE INVENTION
A pre-load indicating washer, constructed in accordance with the present invention, includes an annular body and a plurality of protuberances integral with the annular body struck and partially sheared from the annular body to project from a first face of the annular body and leave a corresponding plurality of indentations in a second face of the annular body opposite from the first face. This pre-load indicating washer also includes indicia in an outer edge of the annular body in radial alignment with the spaces between the protuberances.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a plan view of one face of a pre-load indicating washer constructed in accordance with the present invention.
Fig. 2 is a plan view of the opposite face of the Fig. 2 pre-load indicating washer.
Fig. 3 is an elevation view of the Figs. 1 and 2 pre-load indicating washer.
Fig. 4 is a sectional view taken along line 4-4 of Fig. 2.
Fig. 5 is a sectional view taken along line 5-5 of Fig. 2.
Fig. 6 is an elevation view of a joint assembly in which a pre-load indicating washer, constructed in accordance with the present invention, can be used prior to tightening.
Fig. 7 is similar to Fig. 6 but shows the joint assembly after tightening.
DETAILED DESCRIPTION OF THE INVENTION
Referring to Figs. 1 through 5, a pre-load indicating washer 40, constructed in accordance with the present invention, includes an annular body 42 and a plurality of protuberances 44 integral with the annular body struck and partially sheared from the annular body to project from a first face 46 of the annular body and leave a corresponding plurality of indentations 48 in a second face 5Q of the annular body opposite from face 46.
For the embodiment of the present invention. illustrated in Figs. 1 through 5, protuberances 44 are spaced circumferentially at regular intervals between the circular inner periphery 52 of annular body 42 and the circular outer edge 54 of the annular body Protuberances 44 are substantially oblong in outline, each with its greater length extending in the direction of a line tangential te a circle around and concentric with circular outer edge 54 of annular body 42. Each protuberance 44 has a convex outer surface 56 extending between a pair of outer side walls 58 and 60 and extending arcuately in the direction of its greater length between two spaced regions 62 and 64 of face 46 of annular body 42.Side walls 58 and 60 of protuberances 44 extend substantially tangential to circles concentric with circular outer edge 54 of annular body 42. Each indentation 48 has a concave inner surface 66 extending between a pair of inner side walls 68 and 70 and extending arcuately in the direction of its greater length between two spaced regions 72 and 74 of face SO of annular body 42. Concave inner surfaces 66 of indentations 48 are substantially complementary to their associated convex outer surfaces 56 of protuberances 44.
Pre-load indicating washer 40 also has indicia in circular outer edge 54 of annular body 42 in radial alignment with the spaces (i.e,, spaced regions 62 and 64 of face 46) between protuberances 44. For the eiflbodiment of the invention being described, these indicia are notches 73 extending from face 46 of the annular body to face 50 of the annular body. These notches can be farmed as the annular body is being stamped.
Pre-load indicating washer 40 preferably is made from steel and has been heat treated after formation of the proti;berances and indentations. It will be apparent that other materials can be used and that heat treatment is not always required to develop the desired properties.
The use of a pre-load indicating washer, constructed in accordance with the present invention, is illustrated in Figs. 6 and 7. A joint assembly, comprising a pair of joint members 76 and 78, an externally threaded member in the form a bolt 80, an internally threaded member in the form of a' nut 82, and a pair of standard washers 84 and 86, is assembled with the proper tension in the bolt by use of pre-load indicating washer 40.The pre-load indicating washer is positioned somewhere between head 80a of bolt 80 and nut 82 which is in threaded engagement with shank 80b of the bolt so that the pre-load indicating washer is subiected to the clamping load between the bolt and the nut as the joint assembly is tightened. For the particular arrangement illustrated in Figs. 6 and 7, pre-load indicating washer 40 is positioned against head 80a of bolt 80 with the underside bearing surface of the bolt head bearing against the tops of the protuberances of pre-load indicating washer 40. The joint is tightened either by driving bolt 80 or nut 82 with the protuberances isolated, for example by a washer, from the component being turned.For the arrangement shown in Figs. 6 and 7, nut 82 is turned. As tightening proceeds, the protuberances of the pre-load indicating washer collapse into their associated indentations and the gap between the top surface of pre-load indicating washer 40 and the underside bearing surface of the bolt head is reduced.
When this gap has been reduced a prescribed amount, as measured by a feeler" gage, tightening is stopped because the gap represents proper tensioning of bolt 80.
This is so because the number and size of the protuberances have been selected with respect to the compressive force applied by the nut and the bolt, 8o that the protuberances will plastically deform into the annular body when the compressive force applied to the pre-load indicating washer has reached the desired tension in the bolt. The Feeler gage can be inserted into the space between two protuberances quickly, easily and properly with the assistance of one of the notches 73 (not shown in Figs. 6 and 7) which is in radial alignment with the space between two protuberances and is visible at the circular outer edge Of the annular body of the pre-load indicating washer.
While in the foregoing there has been described a preferred embodiment of the present invention, it should be obvious to those skilled in the art that various modifications and changes can be made without departing from the true spirit and scope of the invention.
Claims (20)
1. A preload indicating washer comprising:
an annular body;
a plurality of protuberances integral with said annular body struck and partially sheared from said annular body to project from a first face of said annular body and leave a corresponding plurality of indentations in a second face of said annular body opposite from said first face, said protuberances having spaces therebetween adapted to receive a feeler gage when said washer is in a joint being tightened;
and indicia in an outer edge of said annular body in radial alignment with said spaces between said protuberances.
2. A pre-load indicating washer according to claim 1 wherein said protuberances are spaced circumferentially.
3. A pre-load indicating washer according to claim 2 wherein said indicia are notches extending from said first face of said annular body to said second face of said annular body.
4. A pre-load indicating washer according to claim 2 wherein each of said protuberances is oblong in outline and has a pair of side walls extending away from said first face of said annular body.
5. A pre-load indicating washer according to claim 4 wherein said outer edge of said annular body is circular and said side walls of said protuberances extend substantially tangential to circles concentric with said circular outer edge of said annular body.
6. A pre-load indicating washer according to claim 5 wherein said indicia are notches extending from said first face of said annular body to said second face of said annular body.
7. A joint assembly comprising:
at least one joint member;
an externally threaded member extending through said joint member;
an internally threaded member into which one end of said externally threaded member is turned;
and a pre-load indicating washer disposed between saEd internally threaded member and an opposite end of said externally threaded member and comprising::
(a) an annular body,
(b) a plurality of protuberances integral with
said annular body struck and partially sheared
from said annular body to project from a first
face of said annular body and leave a
corresponding plurality of indentations in a
second face of said annular body opposite from
said first face, said protuberances having
spaces therebetween adapted to receive a feeler
gage when said washer is in a joint being
tightened, and
(c) indicia in an outer edge of said. annular
body in radial alignment with said spaces
between said protuberances.
8. A joint assembly according to claim 7 wherein said joint assembly includes a pair of joint members, said externally threaded member is a bolt extending through said pair of joint members and having a head and a threaded shank, and said internally threaded member is a nut in threaded engagement with said threaded shank of said bolt.
9. A joint assembly according to claim 8 wherein said pre-load indicating washer is positioned against said head of said bolt with said protuberances bearing against said head of said bolt.
10. A joint assembly according to claim 8 wherein said protuberances of said pre-load indicating washer are spaced circumferentially.
11. A joint assembly according to claim 10 wherein said indicia of said pre-load indicating washer are notches extending from said first face of said annular body of said pre-load indicating washer to said second face of said annular body.
12. A joint assembly according to claim 10 wherein each of said protuberances of said pre-load indicating washer is oblong in outline and has a pair of side walls extending away from said first face of said annular body of said pre-load indicating washer.
13. A joint assembly according to claim 12 wherein said outer edge of said annular body of said preload indicating washer is circular and said side walls of said protuberances of said pre-load indicating washer extend substantially tangential to circles concentric with said circular outer edge of said annular body.
14. A joint assembly according to claim 13 wherein said indicia of said pre-load indicating washer are notches extending from said first face of said annular body of said pre-loading indicating washer to said second face of said annular body.
15. A pre-load indicating washer according to claim 1 wherein said annular body has a circular outer edge.
16. A pre-load indicating washer according to claim 3 wherein said annular body has a circular outer edge except at said notches.
17. A joint assembly according to claim 7 wherein said annular body of said pre-load indicating washer has a circular outer edge.
18. A joint assembly according to claim 11 wherein said annular body of said pre-load indicating washer has a circular outer edge except at said notches.
19. A preload indicating washer substantially as hereinbefore described, with reference to and as shown in the accompanying drawings.
20. A joint assembly substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US82823792A | 1992-01-30 | 1992-01-30 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9301634D0 GB9301634D0 (en) | 1993-03-17 |
| GB2263745A true GB2263745A (en) | 1993-08-04 |
Family
ID=25251232
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9301634A Withdrawn GB2263745A (en) | 1992-01-30 | 1993-01-27 | "load indicating washer" |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2263745A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5370483A (en) * | 1993-06-24 | 1994-12-06 | J & M Turner, Inc. | Direct tension indicator washer |
| WO1997029288A1 (en) * | 1996-02-06 | 1997-08-14 | Turner, F., Jonathan, M. | Direct tension indicator washer |
| GB2326921A (en) * | 1997-07-04 | 1999-01-06 | Mark Andrew Graham | Collapsable washer |
| DE102005021868A1 (en) * | 2005-05-11 | 2006-12-07 | Zf Friedrichshafen Ag | Shaft to collar connection e.g. for adjusting defined preload force, has shaft nut which covers plastic ductile element with defined cross section in axial direction |
| ES2699362A1 (en) * | 2017-04-11 | 2019-02-08 | Turnasure Llc | A DIRECT TENSION INDICATOR WASHER (Machine-translation by Google Translate, not legally binding) |
| CN113330223A (en) * | 2019-01-08 | 2021-08-31 | 锚固技术应用公司 | Flange bolt connection method and device |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1006452A (en) * | 1961-06-13 | 1965-10-06 | Cooper & Turner Ltd | Improvements in or relating to a fastener assembly and pre-load indicating washer therefor |
| GB1116948A (en) * | 1962-12-14 | 1968-06-12 | Cooper & Turner Ltd | An improvement in or relating to pre-load indicating washers |
-
1993
- 1993-01-27 GB GB9301634A patent/GB2263745A/en not_active Withdrawn
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1006452A (en) * | 1961-06-13 | 1965-10-06 | Cooper & Turner Ltd | Improvements in or relating to a fastener assembly and pre-load indicating washer therefor |
| GB1116948A (en) * | 1962-12-14 | 1968-06-12 | Cooper & Turner Ltd | An improvement in or relating to pre-load indicating washers |
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2279421A (en) * | 1993-06-24 | 1995-01-04 | Turner J & M Inc | Load indicating washer |
| US5487632A (en) * | 1993-06-24 | 1996-01-30 | J & M Turner, Inc. | Direct tension indicator washer |
| GB2279421B (en) * | 1993-06-24 | 1996-07-03 | Turner J & M Inc | Direct tension indicator washer |
| US5370483A (en) * | 1993-06-24 | 1994-12-06 | J & M Turner, Inc. | Direct tension indicator washer |
| AU707497B2 (en) * | 1996-02-06 | 1999-07-08 | Turner, F. Jonathan M | A pre-load indicating washer and a joint assembly comprising such a washer |
| WO1997029288A1 (en) * | 1996-02-06 | 1997-08-14 | Turner, F., Jonathan, M. | Direct tension indicator washer |
| US5667346A (en) * | 1996-02-06 | 1997-09-16 | F. Jonathan M. Turner | Direct tension indicator washer |
| GB2326921A (en) * | 1997-07-04 | 1999-01-06 | Mark Andrew Graham | Collapsable washer |
| GB2326921B (en) * | 1997-07-04 | 1999-07-28 | Mark Andrew Graham | Collapsible washer |
| DE102005021868A1 (en) * | 2005-05-11 | 2006-12-07 | Zf Friedrichshafen Ag | Shaft to collar connection e.g. for adjusting defined preload force, has shaft nut which covers plastic ductile element with defined cross section in axial direction |
| ES2699362A1 (en) * | 2017-04-11 | 2019-02-08 | Turnasure Llc | A DIRECT TENSION INDICATOR WASHER (Machine-translation by Google Translate, not legally binding) |
| US10738817B2 (en) | 2017-04-11 | 2020-08-11 | Turnasure Llc | Self-indicating direct tension indicator |
| CN113330223A (en) * | 2019-01-08 | 2021-08-31 | 锚固技术应用公司 | Flange bolt connection method and device |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9301634D0 (en) | 1993-03-17 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |