CH342042A - Method for cold manufacturing the outer part of a safety nut comprising two parts - Google Patents

Description

Process for cold manufacturing the outer part of a safety nut comprising two parts The present patent comprises a process for cold manufacturing the outer part of a safety nut comprising two pikes, one, internal, split on its entire height and having a tapped hole, its outer wall being frustoconical over part of its height, the rest of its wall being prismatic, the other, external, enveloping the first and having an internal recess of a shape corresponding approximately to that of the internal pike, a collar machined on the external pike holding the internal piece prisoner therein, a process consisting in cutting off an element in a profile6, perpendicular to the face of the latter, a cylindrical hole being made in the this 616ment.

One of the known methods of manufacturing the safety nuts indicated above consists in forming with a single blow of a press, given cold, the external peg or the internal peg of the nut, starting from a ring token. This process requires, however, expensive tooling, different for almost all nut diameters and, especially for relatively large diameters, high-power presses.

The purpose of the present patent is to allow the manufacture of the external pike of the safety nut indicated above, cold, with tools of a lower price and presses of reduced power compared to those required known processes.

The cold manufacturing process of the external pick of a safety nut is characterized by the fact that this element is milled internally in the shape of a truncated cone according to an angle corresponding to that of the internal pick, then by the fact that a hollow polyhedron is printed in the part of the recess adjacent to the large base of the truncated cone, the retaining collar of the internal piece being obtained by cutting.

The patent also includes the external pick of a safety lock comprising two pieces, this piece being characterized by the fact that it is obtained by the above process.

The appended drawing represents, schematically and by way of example, the various stages of manufacture of the external pike of a safety nut.

fig. 1 is a sectional view of such a complete süret6 6crou engaged on a screw.

Figs. 2 and 3 show in elevation, respectively in plan, an element from which the external peg of the safety nut according to FIG. 1. Figs. 4 and 5 are, respectively, a 616vation view and a plan view of the same element as that of FIGS. 2 and 3, after centric drilling. Figs. 6 and 7 represent in elevation or in section, respectively in plan, the 1'616ment after the first per@age of a frustoconical hole. _ Figs. 8 and 9 show, respectively in cross-sectional elevation and in plan view, the element after press printing of a hollow polyhedron in the part of the recess adjacent to the large base of the truncated cone.

Figs. 10 and 11 represent a variant in which the frustoconical recess presents a double taper; the figs. 12 and 13 being the views, respectively in elevation in section and in plan, of the element represented in FIGS. 10 and 11, after press printing the hollow polymer.

Figs. 14 and 15 represent, respectively in sectional elevation and in plan view, a second variant. The manufacturing process described with reference to the drawing relates more particularly to a safety nut comprising two pegs, an internal one 1 having a slot 2 all the way up to its height and in which a tapped hole 3 is machined. piece 1 is frustoconical over part 4 of its height, the first remainder 5 of its wall being prismatic. The second pike forming part of this safety nut 6 is an external part 6 enveloping the first part 1 and having an internal recess 7 of a shape corresponding approximately to that of the pike 1. The outer wall of this external pike 6 is prismatic, in the example represents, so as to allow it to be driven using a key, for example. A collar 8 is made on this outer piece 6. This collar is folded inwards, as shown in FIG. 1, after engagement of the pike 1 in the recess 7, to maintain said internal pike 1 prisoner in the external pike 6.

The process for manufacturing this part 6 consists first of all in cutting off an element 9 in a profile, perpendicular to the latter. In the case where Fon desires that the safety krou be at six paus, an uses a hexagonal section profile. This element 9 is then pierced with a cylindrical hole 10 centered on the axis. Of course, as a variant, an element 9 could also be cut off from a profile already having a hole 10 along its entire length, which would avoid the second operation shown in FIGS. 4 and 5.

The element 9 is then milled internally so as to form the recess 7 in the shape of a truncated cone over the entire height of the element 9. The angle of taper of this milling is chosen so as to correspond to the angle of taper of part 4 of internal pike 1. Element 9 is then engaged in a die and a frustoconical mandrel is introduced into recess 7, this frustoconical mandrel having a height equal to that which will separate the lower face 11 from the piece 6 ends, from the base 12 of its polyhedral part 13. This hollow polyMre 13 is printed on the press by engaging a punch of corresponding shape in the upper part of the recess 7. RTI ID="0002.0274" WI="6" HE="4" LX="343" LY="2537"> view of figs. 8 and 9, the punch engaged in the recess 7 has little material to be upset to form the hollow polymer 13, since most of the material has already been removed from the milling. Therefore, a low power press can be used for this operation.

The faces of the polyMre 13 imprinted hollow in the pike 6 may be either completely flat, or partially cut by the internal countersinking carried out previously, this according to the dimensions and the shape of the internal polyhedron, the angle of inclination of there where. interior countersinks of the recess 7 and the height of the 9 worked 1'616ment.

Figs. 10 to 13 specifically show a variant of the method for manufacturing the outer part 6 according to which the recess 7 is milled under a double conicity. As seen in fig. 10, the conicity angle of the part 14 of the recess 7 is smaller with respect to the recess of the recess than the conicity angle of the part 15, an angle which corresponds to that of the part 4 of the internal part 1. When the first polyMre 13 is printed in a 61ement 9 prepared as represented in FIGS. 10 and 11, certain tapered portions 16 appear between the planar faces 17 of the polyMre 13. Once the press printing of the hollow polyMre 13 has been completed, the collar 8 is cut into the upper part of the element 9. The internal pike 1 can then be introduced into the external pike 6, the collar 8 dtant folded down towards the first center of the pike 6 to keep the pike 1 prisoner in the latter, the angles 18 of the prismatic part 5 of the pike 1 engaging in the dihedrals 19 forms between each pair of adjacent 17 faces of the pike 6.

According to another alternative embodiment of the process described above, after the recess 7 has been milled in the recess 9, a groove 20 is formed inside this recess 7, the largest diameter of which is at least equal to the largest dimension of the hollow polyMre 13 of the finished part, upper edge 21 of this groove 20 being at the height of the base 12 of the polyMre 13. In this case, the impression of the hollow polyMre 13 is made by engaging in element 9 a polyhedral chisel adopts the cutting edge to the shape of the section of the polymer 13, down to the said groove 20. This impression of the hollow polymer 13 therefore requires even less power, given that the material of the dlement 9 is not bent, but is simply sheared off in a way. 11 should be noted that this impression starting from an element 9 prepared as RTI ID="0002.0545" WI="11" HE="4" LX="1655" LY="2153"> shown in FIGS. 14 and 15 could require even less power if, instead of using a complete polyhedral chisel, one used a chisel whose cutting edge corresponds to a fraction of the complete polymer 13 that one wishes to obtain. In this case, the printing of the hollow polymer would require less power but would have to be repeated several times after a relative angular displacement between the chisel and the element 9, so as to gradually print the complete polymer.

By manufacturing the external pike 6 according to the first process partially represented in FIGS. 14 and 15, and given that the material of the element 9 is not repressed, it is possible to carry out the printing of the hollow polyhedron 13 without introducing a mandrel into the bottom of the recess 7.

As a further variant and instead of introducing a mandrel into the bottom of the recess 7, an could provide the polyhedron impression punch 13 with a conical or frustoconical tip adopting the shape corresponding to that of the part 4 of the outer wall of the inner pike 1.

In another variant of the process, the collar 8 could be machined before the printing of the hollow polyhedron 13, for example simultaneously with the milling of the recess 7.

Claims (4)

CLAIMS 1. Process for the cold manufacture of the outer part of a safety nut comprising two parts, Tune, internal, split over its entire height and presenting a tapped hole, its outer wall being truncated on a part of its height, the rest of its wall being prismatic, the other, external, enveloping the first and presenting an internal recess of a shape corresponding approximately to that of the internal pike, a flange machined on the external pike holding the internal piece prisoner in that of the internal pike -this, process consisting in truncating an element in a profile, perpendicular to its axis, a cylindrical hole being made in this element, characterized by the fact that this element is milled internally in the form of a truncated cone according to an angle corresponding to that of the internal piece, then by the fact that a hollow polyhedron is printed in the part of the recess adjacent to the large bar of the truncated cone, the retaining collar of the internal piece Aant obtained by bar turning . He. External pike of a safety nut comprising two pike, characterized in that it is obtained by the process according to claim I. SUB-CLAIMS 1. Process according to claim I, characterized in that, after the milling, a neckline inside the outer pike has a groove whose largest diameter is at least equal to the largest dimension of the hollow polyhedron of the finished pike, the upper edge of this groove being at the height of the base of the this polyhedron, the impression of the hollow polyhedron being made by inserting a polyhedral chisel into the pike, the cutting edge of which has the shape of the section of the polyhedron, into said groove. 2. Process according to claim I, characterized by the fact that, after the first milling, a groove is cut inside the external pike, the largest diameter of which is at least equal to the largest dimension of the hollow polyhedron of the pike. finished, RTI ID="0003.0272" WI="10" HE="4" LX="1801" LY="844"> the upper edge of this groove being at the height of the base of this polyhedron, 1' impression of the hollow polyhedron being made by engaging, several times in the pike, a chisel, the cutting edge of which corresponds to a fraction of the complete polyhedron, after relative angular displacement between the chisel and the pike, so as to progressively impregnate the complete polyhedron. 3. Process according to claim 1, characterized by the fact that the part of the recess of the external part intended to receive the impression of the polyhedron is milled in the shape of a truncated cone at a smaller angle with respect to the angle of 1 of course that the angle of conicity of the rest of the recess which corresponds to that of the internal piece. 4. Process according to claim 1, according to which the said element is engaged in a die before the printing of the polyhedron, characterized in that a frustoconical mandrel of a height equal to that which separates the lower face of the external part is introduced. finished from the base of its poly6edxic part before printing this one.