US3924434A

US3924434A - Apparatus for shaping hollow metal bodies

Info

Publication number: US3924434A
Application number: US463915A
Authority: US
Inventors: Josef Fulier
Original assignee: VYSKUMNY USTAV MECHANIZACIE A AUTOMATIZACIE
Current assignee: VYSKUMNY USTAV MECHANIZACIE A AUTOMATIZACIE
Priority date: 1974-04-04
Filing date: 1974-04-25
Publication date: 1975-12-09
Anticipated expiration: 1992-12-09
Also published as: NL7404689A; NL173031B; FR2274375B1; NL173031C; GB1462429A; FR2274375A1

Abstract

Apparatus for shaping hollow metal bodies such as hollow rivets and the like on a mandrel including a hollow supporting sleeve adapted to receive the body and the mandrel. At least two forming bodies located in openings in the wall of the supporting sleeve, symmetrically with respect to the longitudinal axis of the sleeve. The forming bodies such as freely rotating balls or rollers with their external circumference against a pressure element surrounding at least in part the supporting sleeve and biasing the forming bodies against the surface of the hollow body.

Description

United States Patent 1191 1111 3,924,434

Fulier Dec. 9, 1975 APPARATUS FOR SHAPING HOLLOW 1,919,869 711933 Stanitz et al. 72/75 METAL BODIES 1,974,566 9/1934 Garrett 2,371,697 3/1945 Logan 72/224 [75] Inventor: Josef Fuller, Nove Mesto nad Vahom Czechoslovakla Primary Examinerl ;owell A. Larson [73] Assignee: Vyskumny ustav mechanizacie a L automatizacie, Nove Mesto nad ABSTRACT Vahom, Czechoslovakia 2 Fl d: A Apparatus for shaping hollow metal bodies such as [2 1 1e pr 1974 hollow rivets and the like on a mandrel including a PP 463,915 hollow supporting sleeve adapted to receive the body and the mandrel. At least two forming bodies located in openings in the wall of the supporting sleeve, symlifl E385:JJJJJJJJJJJJJJJJ:11:33:13???T 14331; 1213i liiiiiiilly will ii iii lilgiililiiil ii iii 58 Field of Search 72/75 224 20s Sleeve- The forming bodies such as freely rotating bans or rollers with their external circumference against a [56] References Cited pressure lelement csuli'roundinfig aft least inbpgrt the supporting s eeve an lasing t e orming o ies against UNITED STATES PATENTS the surface of the hollow body. 629,245 7/1899 Frank 72/75 1,418,697 6/1922 Brinkman 72/75 10 Claims, 5 Drawing Figures US. Patent Dec. 9 1975 3,924,434

APPARATUS FOR SHAPING HOLLOW METAL BODIES BACKGROUND OF THE INVENTION The present invention relates to an arrangement for shaping hollow metal bodies and particularly for shaping and forming hollow rivets, blind or one-sided rivets and the like.

Hollow rivets, particularly blind rivets must be shaped and formed on their external and internal surfaces with grooves, serrations, rachet teeth or the like in order that they assume the proper shape after riveting and in order that they are capable of being grasped by the mandrel of the riveting tool for blind insertion. In general hollow cylindrical workpieces are shaped after being placed over the pull or tear mandrel of the insertion tool by compressing the rivet between suitable dies. This operation occurs when the mandrel is fixed to the insertion tool and fixes the body into the mandrel. Reference to my copending application Ser. No. 335,747 filed Feb. 26, 1973, now US. Pat. No. 3,838,499, issued Oct. 1, 1974, will show such an arrangement. This procedure has the disadvantage in that the dies needed to compress the rivet while the mandrel is on the forming tool are rather complicated and difficult to manufacture. Furthermore, their maintenance and repair is costly and uneconomical.

It is an object of the present invention to provide apparatus for shaping hollow metal bodies into rivets and the like in which the drawbacks and disadvantages of the prior art are overcome.

It is a further object of the present invention to provide apparatus of the type described which would allow the formation of rivets and the like from hollow metal bodies easily and efficiently.

It is a further object of the present invention to provide apparatus for shaping hollow metal bodies into rivets in which the apparatus is simple and uncomplicated and which will permit the formation of rivets of different shape.

The foregoing objects, together with numerous other objects and advantages, will be apparent from the following disclosure of the present invention.

SUMMARY OF THE INVENTION According to the present invention apparatus is provided for forming hollow rivets and the like from hollow metal bodies comprising a hollow cylindrical support. The support is provided with at least two openings in its wall symmetrically arranged along the longitudinal axis. A freely rotatable forming body is located in each of the openings so as to extend into the bore of the hollow support and outwardly of the external surface of the support. A pressure element is mounted on the support so as to engage the external circumference of the forming body and to urge the forming body radially inward whereby on insertion of a hollow metal workpiece and its supporting mandrel, the forming bodies roll over the external surface of the workpiece and compress the same under pressure of the pressure element against the mandrel.

The forming bodies can have the shape of balls or cylindrical rollers suitably held in the openings by either shaping the openings or providing the same with freely rotatable axles. The pressure element can be a sleeve completely surrounding the cylindrical support and being provided with resilient spring means normally biasing the sleeve against movement but permitting movement in a direction opposite to that of the movement of the workpiece when the workpiece is inserted in the apparatus. The pressure element can also be formed as rollers fixed about an axle secured to the cylindrical support and in contact with the forming element.

With the foregoing arrangement, the hollow workpieces can be shaped or reshaped along their longitudinal axis so as to obtain a modification of the profile of its cross section. The apparatus not only shapes the exterior surface but compresses the material against the mandrel holding the workpiece so that the inner surface is also shaped. The present apparatus uses substantially smaller forces than those required for normal die shaping. Another advantage of the present apparatus is that a variety of profiles and the degree of shaping of the internal and external surfaces can be achieved which surpasses that normally obtained by the prior known apparatus.

Full details of the present invention are set forth in the following description and in the accompanying drawing.

DESCRIPTION OF DRAWING In the drawing:

FIG. 1 is a longitudinal sectional view of apparatus for forming hollow rivets embodying the present invention,

FIG. 2 is a view similar to that of FIG. 1 showing a second embodiment of apparatus of the present invention,

FIG. 3 is a partial cross sectional end view showing the formation of the workpiece into the shaped rivet by the apparatus of FIG. 1,

FIG. 4 is a view similar to that of FIG. 3 showing the formation of the rivet in accordance with the apparatus of FIG. 2, and

FIG. 5 is a partial longitudinal sectional view of the hollow workpiece and its supporting mandrel as it is being shaped by the apparatus of either FIG. 1 or 2.

DESCRIPTION OF PREFERRED EMBODIMENT In FIG. 1 one form of the present invention is shown comprising a hollow cylindrical supporting member 10 having a bore 12. The supporting member 10 is provided with a conical outward flare 14 at its forward end and a radial outwardly directed flange 16 at its other end. The cylindrical support is further provided with a pair of diametrically opposed holes 18 in each of which is located a forming body which in the illustrated embodiment comprises a ball 20. The holes 18 are shaped so as to retain the balls 20 and are arranged symmetrically with respect to the longitudinal axis of the support in a common transverse plane. The diameter of each of the balls 20 is larger than the thickness of the wall of the cylindrical support 10 so that its circumferential surface extends beyond the inner and outer surfaces of the support, i.e., into the bore 12 and beyond the mantel of the support 10.

A cylindrical sleeve 22 having a radial outward flange 24 at its rear end surrounds the cylindrical port 10 and extends axially from the flared end 14 into abutment with the flange 16. The sleeve 22 has an inner diameter slightly larger than the outer diameter of the cylindrical support 10 but small enough to engage the circumferential surface of the balls 20 such that it is permitted to slide axially with respect to the support 10 and to simultaneously exert a radial inward pressure on the balls 20. Surrounding the sleeve 22 is a cylindrical cover 26 which'is threaded at its rear end to the flange 16 so as to be maintained in fixed position. The cover 24 is provided with a radially inwardly directed flange 28 at its forward end. Arranged between the flanges 24 of the slidable sleeve 22 and the flange 28 of the cover 26 is a spring 30 which acts to normally bias the slidable sleeve 22 in its rearward direction. In forming a blind rivet or similar member, a cylindrical hollow workpiece 32 is initially located over a pull or tear mandrel 34 having in the usual manner an inner diameter barely smaller than that of the workpiece and having a contour conforming to the desired shape to be given to the internal surface of the workpiece. For example, as seen in FIG. the mandrel is formed with a threaded portion 36 and in FIGS. 3 and 4 with special cross sectional shapes. Various contours, shapes and threads may be provided in any desired combination.

The workpiece 32 and its mandrel 34 are simultaneously inserted into the front or flared end of the bore '12 and pushed manually or mechanically in the direction of the arrow toward the rear end 16. As soon as the workpiece contacts the surface of the balls 20 the balls start to turn and roll over the surface of the workpiece 32 and under the pressure of the pressure sleeve 22 form a longitudinal depression 38 on the outer surface simultaneously upsetting the material of the workpiece ,so that its inner surface is compressed into the shape of the mandrel. As the balls 20 turn, moving counter clockwise, the pressure sleeve also begins to move axially in a direction opposite to that of the moving workpiece and against the normal bias of the spring 30. This allows the balls 20 to continue rolling while being urged radially inward with sufficient pressure to form the depressions 38. The workpiece may be moved completely through the support or it may be withdrawn after only partial passage therethrough. In either event, the pressure sleeve 22 will return to its initial starting position as seen in FIG. 1; in the first instance under action of the spring 30, or in the second instance by rolling contact contrary to the movement of the workpiece and combined with the action of the spring. Due to the arrangement of the movable pressure sleeve 22 friction between the balls 20 and the sleeve and/or the workpiece 32 is reduced to a minimum.

In FIG. 2 a modification of the apparatus according to the present invention is shown in which the pressure element rather than being a sleeve completely surrounding the cylindrical support, comprises a pair of rollers 40 mounted about an axle 42 secured in a bracket 44 fixed to the flange 16 of the support 10. The support being modified only to the extent to accommodate the bracket. As seen in FIG. 2 the axial length of the support may be chosen as desired in either embodiment. The operation of the apparatus according to FIG. 2 is similar to that described with regard to FIG. 1. The rotating pressure rollers reduce the friction between the forrning bodies and the rollers and because they do not have a finite length as does the pressure sleeve 22 of FIG. 1, hollow metal bodies of longer length may be pulled or pushed through the bore. Further, the rollers 40 have no fixed directional bias and thus workpieces can be pulled or pushed through the apparatus from either the front or its rear ends. Workpieces can furthermore be fed sequentially through the apparatus of FIG. 2 one after the other.

The number of forming bodies, such as the balls depend upon the exterior shape which is to be given to the rivet. They may be in any desired number and of any desired diameter. As seen in FIG. 4 the forming bodies may be replaced by cylindrical rollers which provide a flat, rather than an arcuate contour. In the apparatus of FIG. 2, if a small number of forming bodies are to be used, the apparatus may be further modified by utilizing the pressure rollers 40, in the shape of cylindrical rotating rollers as the forming body, thereby eliminating one member of the apparatus. The pressure rollers 40 would then be mounted so as to extend through the openings 18 into contact with the face of the workpiece. The cylindrical support 10 is suitably mounted on a frame or other device, not shown herein.

The arrangement according to the present invention is particularly adapted for the formation of hollow metal rivets to conform to the pull or tear mandrel on which they are used. It is however possible to employ the present arrangement in other applications wherein recesses along longitudinal axes of hollow metal bodies have to be formed or where the wall of a hollow metal body should be shaped on its internal surface by means of an inserted mandrel or other inserted die. The present invention can also be used advantageously for the manufacture of a variety of nuts and similar devices each being formed from hollow cylindrical bodies.

Several modifications and changes have been described herein, other modifications and changes will be obvious to those skilled in the art. It is therefore intended that the present disclosure be taken as illustrative only and not as limiting the present invention.

What is claimed is:

1. Apparatus for shaping hollow metal blind rivets comprising a hollow support having a cylindrical bore, at least one radial opening formed in said support, forming elements rotatably arranged in said radial openings and extending into said bore, an elongated mandrel for receiving and axially inserting said rivets within said bore, said mandrel having an outer contour v conforming to the desired shape of said rivet, a'movable pressure element at least partially surrounding said support and engaging the external surfaces of the forming element to conjointly roll therewith and to exert a radially inward force on each movement of said mandrel and rivet through said bore, to cause said forming elements to shape said rivet.

2. The apparatus according to claim 1 wherein th forming element is spherical.

3. The apparatus according to claim 1 wherein the forming element comprises a cylindrical roller.

4. The apparatus according to claim 1 wherein the pressure element comprises a sleeve surrounding said support and is provided with resilient means normally biasing said sleeve again st axial movement in one direction the movement of said rivet and mandrel through said bore, overcoming said bias. 1

5. The apparatus according to claim 4 including means for limiting the axial movement of said sleeve in said one direction.

6. The apparatus according to claim 1 wherein the pressure element is formed by a rotating roller journalled on said support and rotatable about an axis angular to the axis of the cylindrical bore.

7. The apparatus according to claim 1 .wherein said pressure element comprises a member movable with respect to both said forming element and said hollow support.

8. The apparatus according to claim 1 wherein said forming elements are freely mounted within openings and being movable radially with respect to said support, said pressure element being spaced from the surface of said support and limiting the outward movement of said forming element.

9. The apparatus according to claim 1 wherein the pressure element.

Claims

1. Apparatus for shaping hollow metal blind rivets comprising a hollow support having a cylindrical bore, at least one radial opening formed in said support, forming elements rotatably arranged in said radial openings and extending into said bore, an elongated mandrel for receiving and axially inserting said rivets within said bore, said mandrel having an outer contour conforming to the desired shape of said rivet, a movable pressure element at least partially surrounding said support and engaging the external surfaces of the forming element to conjointly roll therewith and to exert a radially inward force on each movement of said mandrel and rivet through said bore, to cause said forming elements to shape said rivet.

2. The apparatus according to claim 1 wherein the forming element is spherical.

4. The apparatus according to claim 1 wherein the pressure element comprises a sleeve surrounding said support and is provided with resilient means normally biasing said sleeve against axial movement in one direction the movement of said rivet and mandrel through said bore, overcoming said bias.

7. The apparatus according to claim 1 wherein said pressure element comprises a member movable with respect to both said forming element and said hollow support.

9. The apparatus according to claim 1 wherein the contour of said mandrel conforms to that of the forming elements.

10. The apparatus according to claim 1 wherein a plurality of openings are formed in the support, symmetrically with respect to longitudinal axis, each having a forming element arranged therein and an associated pressure element.