CA1135082A - Split setting mandrel for blind rivet - Google Patents
Split setting mandrel for blind rivetInfo
- Publication number
- CA1135082A CA1135082A CA000356654A CA356654A CA1135082A CA 1135082 A CA1135082 A CA 1135082A CA 000356654 A CA000356654 A CA 000356654A CA 356654 A CA356654 A CA 356654A CA 1135082 A CA1135082 A CA 1135082A
- Authority
- CA
- Canada
- Prior art keywords
- mandrel
- head
- under
- pyramidal
- rivet
- 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.)
- Expired
Links
Abstract
Abstract of the Disclosure A pull-type blind riveting assembly including a hollow rivet and a mandrel. The mandrel is provided with a pyramidal under-surface which causes the tail end of the rivet to split into petals. The mandrel head has a flat shoulder that engages the tail end of the mandrel.
Description
~13Sl~2 This invention i9 concerned with pull-type blind-riveting assemblies comprising a hollow rivet and a mandrel, the mandrel having a head with a pyramidal under-surface which provides radially disposed ridges to cause the tail end of the rivet to split into petals when the mandrel head is pulled into it on setting the rivet. Split-setting blind-riveting assemblies are of 5 two kinds, viz. those in which the rivet barrel has longitudinal lines of weakness where it will split into petals when a mandrel head is pulled ~nto it and those where the rivet barrel has no such lines of weakness but splitting i8 induced by radially disposed ridges on the under-surface of the mandrel head. Such ridges are usually provided by the edges of a three, four or 10 five sided pyramidal configuration of such surface, the pyramidal configuration extending substantially from the periphery of a mandrel head to a cylindrical portion of the mandrel stem.
It is potentially more economical to manufacture the latter type of assembly because the process is less complicated than that required to provide lines 15 of weakness along the rivet shank. ~lowever, it is desirable that the effect of the ridges on the under-surface of the mandrel head is to split the rivet shank evenly into the desired number of petals, i.e. four where the under-surface of a mandrel head is part of a square pyramid, and experience has shown that to ensure such a result requires the rivet shank wall to be of 113SO~
uniform thickness within very close limits of the manu~acturing tolerance.
Where, for example, the rivet bore is eccentric to a small degree outside such tolerance, the shank may split along three lines but not along, or only a short way along, the fourth. The maintenance of the necessary close 5 manufacturing tolerance for the rivet to ensure uniform splitting has proved costly .
It is the object of this invention to provide a split-setting pull-type blind-riveting assembly, the rivet shank of which will split evenly into uniform petals under the influence of a mandrel with radial ridges under its 10 head, and which can be manufactured without observing unduly stringent manufacturing tolerances.
The foregoing object is achieved in accordance with the invention in that the under-surface of the mandrel head meets a cylindrical portion of the stem at a plane normal to the axis of the stem with the result that at least at lj each corner of the pyramidal æurface the mandrel head presents a flat shoulder portion normal to the mandrel stem.
With assemblies in accordance with the invention it has been observed that reliable splitting of the rivet shank into evenly disposed petals has occurred when the bore of the rivet has been eccentric to the outer surface 20 of the shank to an extent outside the stringent manufacturing tolerance that would have ensured such setting with a conventional mandrel in which the pyramidal surface under the head runs down to meet the mandrel stem.
Accordingly, a rivet assembly in accordance with the invention is more economical to manufacture than is the case with conventional split-setting 25 blind-riveting assemblies.
113S08'~
An example of a blind--ri~eting assembly in accordance with the invention is shown in the accompanying drawings in which:
E;igures l and 2 represent the assembly as seen from two different directions at angles of 45 to each other;
Figure 3 is a view of the mandrel of the assembly showing the under-surface of its head, as seen on the line III-III of Figure l; and Figure 4 repre~ents a set rivet.
Referring to the drawings, the assembly comprises a hollow aluminum alloy rivet lO having a head ilange 12 and a shank 14 of uniform wall thickness 10 without any longitudinal lines of weakness.
The exemplary assembly also comprises a steel mandrel 16 having a cylindrical stem 18 with a neck 20 at which it will break in the course of rivet setting and a head 22. The head 22 has a slightly squared-off, near circular periphery 24 with a frusto-pyramidal under-surface 26 which merges 15 with the periphery of the head. The included angle between opposite sides of the pyramidal under-surface of the mandrel head in the drawings is 80.
The difference between the "diagonals" of the head and the minimum "diameter"
is about 0 . 26 mm . (i . e . 5 . 5% of a nominal 4 . 70 mm . diameter head) . The "corners" of the periphery are in alignment with the corners of the pyramidal 20 under-surface. The under-surface 26 of the head meets the stem. 18 at a plane normal to the axis of the stem with the result that the head presents flat shoulder portions 28 normal to the stem at each corner of the pyramidal surface.
At the plane at which the head meets the stem of the mandrel of an assembly in accordance with the invention, the diameter of the stem may be substantially 25 equal to or less than the distance between the flat sides of the pyramidal under--113S~S2 surface, the shoulder referred to accordingly being either confined to the corners of the head or merging with one another around the stem.
It is potentially more economical to manufacture the latter type of assembly because the process is less complicated than that required to provide lines 15 of weakness along the rivet shank. ~lowever, it is desirable that the effect of the ridges on the under-surface of the mandrel head is to split the rivet shank evenly into the desired number of petals, i.e. four where the under-surface of a mandrel head is part of a square pyramid, and experience has shown that to ensure such a result requires the rivet shank wall to be of 113SO~
uniform thickness within very close limits of the manu~acturing tolerance.
Where, for example, the rivet bore is eccentric to a small degree outside such tolerance, the shank may split along three lines but not along, or only a short way along, the fourth. The maintenance of the necessary close 5 manufacturing tolerance for the rivet to ensure uniform splitting has proved costly .
It is the object of this invention to provide a split-setting pull-type blind-riveting assembly, the rivet shank of which will split evenly into uniform petals under the influence of a mandrel with radial ridges under its 10 head, and which can be manufactured without observing unduly stringent manufacturing tolerances.
The foregoing object is achieved in accordance with the invention in that the under-surface of the mandrel head meets a cylindrical portion of the stem at a plane normal to the axis of the stem with the result that at least at lj each corner of the pyramidal æurface the mandrel head presents a flat shoulder portion normal to the mandrel stem.
With assemblies in accordance with the invention it has been observed that reliable splitting of the rivet shank into evenly disposed petals has occurred when the bore of the rivet has been eccentric to the outer surface 20 of the shank to an extent outside the stringent manufacturing tolerance that would have ensured such setting with a conventional mandrel in which the pyramidal surface under the head runs down to meet the mandrel stem.
Accordingly, a rivet assembly in accordance with the invention is more economical to manufacture than is the case with conventional split-setting 25 blind-riveting assemblies.
113S08'~
An example of a blind--ri~eting assembly in accordance with the invention is shown in the accompanying drawings in which:
E;igures l and 2 represent the assembly as seen from two different directions at angles of 45 to each other;
Figure 3 is a view of the mandrel of the assembly showing the under-surface of its head, as seen on the line III-III of Figure l; and Figure 4 repre~ents a set rivet.
Referring to the drawings, the assembly comprises a hollow aluminum alloy rivet lO having a head ilange 12 and a shank 14 of uniform wall thickness 10 without any longitudinal lines of weakness.
The exemplary assembly also comprises a steel mandrel 16 having a cylindrical stem 18 with a neck 20 at which it will break in the course of rivet setting and a head 22. The head 22 has a slightly squared-off, near circular periphery 24 with a frusto-pyramidal under-surface 26 which merges 15 with the periphery of the head. The included angle between opposite sides of the pyramidal under-surface of the mandrel head in the drawings is 80.
The difference between the "diagonals" of the head and the minimum "diameter"
is about 0 . 26 mm . (i . e . 5 . 5% of a nominal 4 . 70 mm . diameter head) . The "corners" of the periphery are in alignment with the corners of the pyramidal 20 under-surface. The under-surface 26 of the head meets the stem. 18 at a plane normal to the axis of the stem with the result that the head presents flat shoulder portions 28 normal to the stem at each corner of the pyramidal surface.
At the plane at which the head meets the stem of the mandrel of an assembly in accordance with the invention, the diameter of the stem may be substantially 25 equal to or less than the distance between the flat sides of the pyramidal under--113S~S2 surface, the shoulder referred to accordingly being either confined to the corners of the head or merging with one another around the stem.
Claims (4)
1. A pull-type blind-riveting assembly comprising a hollow rivet and a mandrel, the mandrel having a head with a pyramidal under-surface which provides radial ridges to cause the tail end of the rivet to split into petals when the mandrel head is pulled into it on setting the rivet characterized in that the under-surface of the mandrel head meets a cylindrical portion of the stem at a plane normal to the axis of the stem with the result that at least at each corner of the pyramidal surface the mandrel head presents a flat shoulder portion normal to the mandrel stem.
2. An assembly according to claim 1 in which the diameter of the mandrel stem adjacent the head is substantially equal to the distance between the flat sides of the pyramidal under-surface.
3. An assembly according to claim 1 the mandrel of which has a square pyramidal surface under its head.
4. An assembly according to claim 3 the periphery of the mandrel head of which is a slightly squared-off circle with its corners in alignment with the corners of the pyramidal under-surface.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP2929476.6 | 1979-07-20 | ||
| DE7920826 | 1979-07-20 | ||
| DE19792929476 DE2929476C2 (en) | 1979-07-20 | 1979-07-20 | Draw-type blind rivet |
| DEG7920826.7 | 1979-07-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1135082A true CA1135082A (en) | 1982-11-09 |
Family
ID=25780103
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000356654A Expired CA1135082A (en) | 1979-07-20 | 1980-07-21 | Split setting mandrel for blind rivet |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1135082A (en) |
-
1980
- 1980-07-21 CA CA000356654A patent/CA1135082A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |