DE1803479A1 - Method and device for forming rivet heads - Google Patents

Description

Dr. Ing. E. BERKENFELD · Di ρ I.-1 ng. H. B E RK EN FE LD, patent attorneys, Cologne Attachment file number

on the submission of October 2, 1968 Sch // Name d. Note General -Electro Mechanical

Corporation

Method and device for forming rivet heads.

The invention relates to the forming of rivet heads and more particularly to that kind of riveting in which a cylindrical Nietrohling is inserted into a rivet hole in the ^w orkpiece, whereupon headers are formed at both ends of the blank to the rivet like finish.

With conventional impact riveting, the heads are usually formed by impact tools that impact the ends of the rivet blank, to shape the heads on it. Because of many concerns about the strike riveting, attempts have been made to achieve the Form rivet heads by applying static compressive forces against the ends of the rivet blank. This riveting is called pressure riveting.

When the Nietrohling in the workpiece is in position, the riveting force seeks to arranged in the rivet hole of the rivet shank portion when forming the rivet heads to expand so that CBR space between the rivet shank and the rivet hole {will be partially filled. This bulging of the shaft is desirable, especially when properly monitored. During impact riveting, however, the bulging of the rivet shank is more or less concentrated on the ends of the shank adjoining the rivet heads, probably as a result of inertial forces, so that a characteristic hourglass shape is produced for the shank. In the previously known pressure riveting, the bulging of the rivet shank is improved, but a less pronounced hourglass shape is still produced for the shank.

With impact riveting, the position of the rivet is monitored axial direction difficult to carry out with the result that

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imperfect rivet heads are difficult to avoid. Here too improves conventional pressure riveting, in which compressive forces are applied to opposite ends of the rivet blank simultaneously or sequentially be brought into action, the monitoring of the formation of the rivet heads, but leaves much to be desired in this regard left over. In this case, the rivet blank also moves axially an uneven distribution of metal at the opposite ends and consequently an imperfect shaping of the head. '

With the usual impact riveting by impact or pressure forces the workpiece held by clamping or in some other way so that the same is a stationary position between the riveting tools maintains. The tools approach the workpiece from opposite directions Sides to shape the opposing heads. The relatively immovable holding of the workpiece in this way between the tools forming the opposing heads was seen as the only practical way to get rivet heads on the opposite ends of a rivet blank.

In accordance with the principles of the invention, a rivet blank is inserted into the rivet holes of workpieces are introduced, which are clamped against each other on their opposite sides. A support tool or anvil is arranged as a support for one end of the rivet blank and a head shaping anvil is placed against the opposite end of the blank pressed to form a rivet head. During the formation of the first rivet head, the clamping force is from that adjacent to the support anvil Side of the workpieces is greater than the clamping force from the side of the workpieces adjoining the head shaping anvil and is also from Sufficient size to hold the workpieces against the head shaping anvil to hold on the one end of the rivet blank exerted head shaping forces.

Having the first head shaped this way, or at least enough is shaped to prevent axial displacement of the blank, the force of the head forming anvil overcomes the clamping force on the side of the workpieces adjoining the support anvil, so that they move against the support anvil, which is kept stationary at all times becomes, whataf the support anvil forms a second head.

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As indicated above, this type of compression molding of the rivet heads at the opposite ends of a rivet blank (through Forming or partially forming a rivet head at one end of the blank, whereupon the workpiece is caused to come against one Moving the support anvil at the other end of the blank to form the second rivet head is a more different approach than before it was assumed that adequate monitoring of the shape of the head during impact riveting can only be achieved if the workpieces be held in a fixed position between the head shaping tools.

In addition to better monitoring of the position of the blank and, accordingly, the formation of more perfect heads, it has been found that the λ new process of pressure-forming the rivet heads further reduces the hourglass shape of the rivet shafts, that is to say that it tends to produce a more uniform bulge along the rivet shaft, which is a is a highly desirable outcome.

Since the support part used in the method according to the invention, the also forms the anvil for forming one rivet head, fastened and is stationary at all times, and only the head shaping anvil on the opposite side of the work piece moves in the axial direction against the rivet blank, the accuracy and control of the Head shaping process significantly increased. Since both heads of the Rivets by a single continuous movement of the head shaping anvil are formed under pressure against the supporting anvil, the | whole riveting device much simplified.

In summary, the following can therefore be noted:

The riveting device has upper and lower annular clamping parts. that come into engagement with the workpieces, as well as upper and lower ones coaxial head shape anchors arranged to form a Hold the cylindrical rivet blank in the rivet hole of the workpieces, with both ends of the blank a predetermined piece from the workpieces stick out to form the material used to shape the heads. When forming the heads, the upper anvil is stationary and the lower anvil is moved against the blank to form a head under pressure. Initially, the force of the upper clamping part exceeds the pressure

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force of the lower anvil, but after the lower head partially is shaped, the increasing force of the lower anvil overcomes the force of the upper clamping part and the continued pressure movement of the lower anvil moves the workpieces and rivet blank upwards, around the upper head against the stationary upper anvil below Form pressure and finish forming the lower head.

The drawings show an exemplary embodiment of the clamping parts for aie workpieces and the head shaping tools according to the invention.

Figures 1-5 show schematically in vertical longitudinal section the successive steps in carrying out the method measure of the invention. Fig. 6 shows schematically in vertical longitudinal section the lower clamping and rivet head forming device, according to Fig. 1. Fig. 7 is a general hydraulic conduit diagram showing the sequential steps of workpiece clamping and Rivet head forming device illustrated.

With reference to Figures 1-5, the individual Functionally described rivet head forming steps according to the invention. In Figures 1-5 two workpieces 10 and 11 are shown, in which a rivet hole 1j5 is formed, which at one end with a countersink 14 is provided. The workpiece clamping and rivet head forming device in accordance with the invention may have elements of a riveting machine, including drilling or other equipment for forming and countersinking the rivet holes. Since the rivet hole forming device and the rivet piercing conveying and introducing device of are of the usual type and do not form part of the invention, the details of these devices need not be shown here.

In Fig. 1, 15 denotes a lower rivet head forming anvil, which is movable in the vertical direction in a lower workpiece clamping sleeve 16. The upper workpiece clamping sleeve is denoted by 17 and the upper rivet head forming anvil is indicated at 18 in FIG. "This part has been withdrawn and is therefore not shown in FIG. 1.

The workpieces 10 and 11 are between the lower and upper Klernm-

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sleeves 16 and 17 clamped securely. A generally cylindrical rivet blank 20 is now inserted into the rivet hole 13. The lower and upper head forming anvils 15 and 18 are made in the in Pig. 2 positions shown moved in order to arrange the Rohlirg20 in the axial direction accordingly and to hold so on the upper and lower sides of the workpieces 10 and 1 ι the corresponding projections for shaping the heads are formed.

The head shaping process now begins. The lower head shaping anvil 15 moves up against the lower end of the blank 20 to start sculpting the lower head. At this point, the upper head forming anvil 18 is or hydraulically locked is securely fastened in the position shown in Figures 2 and 5

keep. At this point the clamping force exceeds the upper ™ Clamping sleeve 17 the Klemmfeiraft of the lower Kiemmhülse 16 and has sized to allow the lower anvil 15 to move upward and at least partially a head 21 to form at the lower end of the rivet blank 20 without the workpieces 10 and 11 moving upwards.

As the formation of the lower head 21 progresses beyond the stage shown in FIG. 3, the upward trend exceeds directed force of the lower head shaping arbor 15 the clamping force of the upper collet 17, the upper head forming anvil 18 still being hydraulically held against axial movement. Accordingly gives the upper clamping sleeve 17 in the upward direction, | followed by the continued upward movement of the lower head shaping anvil 15 forms an upper head 22 and at the same time the formation of the lower head 21 ended. During this formation of the heads, the workpieces 10 and 11 move against the fixed upper anvil 18 upwards, since the upper clamping sleeve 17 of the stronger compressive force of the lower anvil 15 yields upwards.

This upward movement of the workpieces 10 and 11 fits into their The size of the axial shortening of the upper projection of the rivet blank when the upper head 22 is formed. Fig. 5 illustrates only the retracted positions of the lower and upper ferrules 16 and I7 which indicate removal or displacement the workpieces 10 and 11 allow.

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Pig. 6 schematically shows the pressure cylinder arrangement on the lower side of the clamping and forming device which provides the clamping force for the lower clamping sleeve 16 and the head forming pressure for the lower anvil 15. The lower head shaping anvil 15 is attached to a piston 23 in a hydraulic cylinder 24 and the clamping sleeve 16 extends around the anvil 15. The latter has an annular extension 25 which acts within the annular lower clamping sleeve 16 like a piston. A coil spring 26

the Kiemmhülse presses relative to the lower anvil 15 usually at the top in the position shown in FIG. 6.

The spiral spring 26 seeks to move the clamping sleeve 16 relative to the lower one To initially hold anvil 15 in a raised position. In the Space between the anvil 15 and the collet 16 containing the coil spring 26 is introduced pressurized air, which within this Creates an initial pressure.

When introduced into the lower end of the cylinder 24 hydraulic pressure the piston 23 and that supported by the same move Device upwards until the collet 16 is the lower side touches the workpiece. When the piston 23 continues upwards moves, the lower anvil I5 reaches the starting position shown in FIG. The further compression of the air within the space containing the spring 26 creates an upward direction Clamping force of the clamping sleeve 16, which is approximately the same or different at least approximates the size of the downward clamping force which is brought to act on the upper clamping sleeve 17.

Reference should now be made to the hydraulic line diagram of FIG. At 34 there are four hydraulic piston and cylinder units denotes, which work together and are arranged in the circumferential direction to the upper clamping sleeve 17 an axially downward to exert directed force. One of the piston and cylinder units 34 is shown schematically in FIG. 1. According to Fig. 7 is a further piston and cylinder unit 35 *, hereinafter referred to as the counter cylinder is attached to the upper end of the upper head forming anvil 18.

A source of hydraulic pressure medium for the clamp cylinders 34 and

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the counter cylinder 55 is shown at 56 and is connected to the upper ends of the individual clamping cylinders 5 ^ by a line 59 via a four-way valve 57 and a pressure reducing valve j> Q. A pressure relief valve that emptied into a hydraulic reservoir is denoted in FIG. J 40. While the four-way valve 57 is connected in the manner indicated, the lower ends of the clamping cylinders 5 ^ are connected to a container 41 by a line 42. The clamping force of the upper clamping sleeve 17 therefore has a constant magnitude which is produced by the pressure reducing valve 58 during the entire head shaping process.

After the workpieces are clamped in this way, a four-way valve 50 is operated to connect a line 51 for pressure medium behaves λ nism moderately low pressure via a line 52 to the upper end of the cylinder 55, which the upper anvil 18 down to a position moved, which is limited by a (not shown) mechanical stop. This downward movement introduces the rivet blank 20 by means of a conventional rivet conveyor and also brings the upper anvil 18 down into the position shown in FIG upper anvil 18 can be adjusted.

The four-way valve 50 then moves into a blocking position and a second four-way valve 5 ² ^ is actuated in order to supply the full hydraulic pressure to a pressure intensifying chamber 55, through which increased hydraulic pressure via the line 56 on the upper end of the counter cylinder 55 to act is brought so that an upward movement of the upper anvil 18 is effectively prevented.

When the upper plunger reaches this stage in the sequence, all four-way valves that control the lower plunger are closed and the lower anvil 15 is in the Starting position shown in FIG. The four-way valves 60 and 61 are now operated to supply pressure medium to the lower end of the cylinder 24 to be supplied to the extent regulated by a pressure relief valve 65 which is in communication with the line 64.

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The lower anvil 15 moves up and begins to compress of the lower end of the blank 20 until the formation of the head reaches the degree shown in FIG. The lower anvil I5 then continues its upward movement and overcomes the pressure force the upper collet 17 the same force is transmitted through the blank 20 to the hydraulically locked upper anvil 18, so that the upper head 22 is molded under pressure and the molding of the lower head 21 is completed.

After both rivet heads are formed, as shown in FIG. 4, the four-way valve 60 is reversed and the four-way valve 61 is shifted to connect the lower end of the cylinder 2k to the container. The lower anvil 15 and the lower collet 16 are therefore moved to their lower retracted positions as shown in FIG.

After the lower clamping sleeve and the lower anvil are retracted, the four-way valve 50 of the hydraulic system moves the upper pressure piston to the low pressure line 5I to connect with the lower end of the anvil cylinder 35th In addition, the conduit 52 is connected to the container so that the upper anvil 18 is withdrawn. The four-way valve 37 is then reversed to connect the source 36 of pressure medium to the lower ends of the cylinders 3 ^ · so that the upper collet I7 is raised to the inoperative position.

The correct switching of the activity of the individual control valves for the execution of the specified processes is carried out by the usual limit switches, which are actuated when predetermined movements of the parts take place, as well as by pressure-sensitive switches that are in action occur when predetermined printing conditions are reached. Each of the limit switches and the pressure switch triggers the subsequent stage of the operation of the individual four-way valves. The kind of The arrangement and connection of the necessary control switches is common Type and does not need to be described in more detail.

As ^{J #ei: 1} üMlchen riveting machines of this general type can now Nietfcöpfftöbel- "or grinding tools are moved relative to the upper rivet head 22 to the working position, to plane or the material above the upper surface of the upper workpiece 10 to this surface of the workpiece to abrade.

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Claims (10)

Dr. Ing. E. BERKENFELD · D i ρ I.-1 η g. H. B E R K E N F E LD, Patentanwälte, Cologne Attachment file number to the entry from October 2, 1968 vA. Named Note General-Electro Mechanical Corporation, 785 Hertel Avenue, BUFFALO, N.Y., U.S.A. PATENT CLAIMS 1. Device for forming rivet heads at the two ends of a rivet blank, for which purpose the blank is inserted into a rivet hole in the workpiece to be riveted, characterized in that the device has two clamping members (16, 17) which, in order to secure the blank (20 ) to be clamped between them, are movable towards one another, an upsetting device is provided and a device to hold it in a fixed position in contact with one end of the blank (20), a tool (18) forming the rivet head is provided, which is a Has initial position in which it rests against the other end of the blank (20) so that it is axially adjusted and protrudes on both sides of the workpiece (10, 11) by the distance required to form the rivet head To move the tool (18) onto the upsetting tool, a further device is provided in order to apply a force to the clamping member on the side of the upsetting tool on the workpiece (10, 11) that is greater than the force required by the tool (18) forming the rivet head for at least partial formation of a rivet head (18), but significantly less than the full upsetting force of the factory eye (18), so dtÄ the Stowing movement of the tool (Id) against the blank (20) at least partially forms the rivet head at that end of the blank (20) on which the tool rests, then the continuous movement of the tool overcomes the force of the clamping member and that Workpiece (10, left) must move the blank in measurement onto the compression tool in order to compress a head at the de »stäuoftwtykseug & ugechx» th end of the blank and close the rivet head curvature 80SSSQ / 0039 .......... - 9. 2. Apparatus according to claim 1, characterized in that the clamping members are annular and coaxial with the upsetting tool and the head forming tool (18). 3. Apparatus according to claim 1, characterized in that the upsetting movement of the tool against the blank is continuous and progressively increases until both rivet heads are formed are. k. Device according to Claim 2, characterized in that the upsetting movement of the tool against the blank (20) is continuous and increases progressively until both rivet heads are formed. 5. Apparatus according to claim 1, characterized in that the means for holding the clamping member and the means actuated by pressure medium to move the tool (18) forming the rivet head are. 6. Apparatus according to claim 5, characterized in that the upsetting movement of the tool against the blank (20) is continuous and progressively increases until both rivet heads are formed are. 7. Method for forming rivet heads at the two ends of a rivet blank, wqssu the rivet blank is inserted into a rivet hole of the workpiece to be riveted, in that the workpiece is clamped between two Kigmmgiiedjgr a blank in the rivet © eh elng§§t§§ kt; around the elastic belt! a rivet head forming Vterfezgugtn is held to the! © Ming adjusted so that ep ieifcen is the Werfegttiofees at both, "is held fixed one of the tools in eine.i ¹ veFhältnisnäAii position its other tool with tine? increasing force gßgßn the N! §t? ohiing is gtdpüekt, s © the adjacent end of the blank iuj "eh ata" etien gtfenats w ©. " Fe * ia «r blank and the Wepicstttok iureh the tint w © Ffe: s§u§ clamping member next to this one tool can be held, which by force of the other Wtpkituits f © stf © s # ^ il wirä, up to 4fP Wi * des Kiennglifdte * n dem tlßtn Wsrkstui iifetpwun ^ tR i§t # • Θ that the workpiece is moving in the direction of the tine tool Ill ι I PI M moves away and this forms a head at the adjacent end of the blank, and the movement of the other tool in the direction of one tool is continued until both heads are fully formed. 8. The method according to claim 7, characterized in that the movement of the other tool during the head formation stages, which overcomes the resistance of the clamping member in addition to preceding and following one tool is essentially continuous. 9. The method according to claim 7, characterized in that the other tool with a progressively increasing pressure | teldruck is moved against the blank. 10. The method according to claim 7 »characterized in that the clamping member located next to the one tool is held on the workpiece by pressure medium pressure and the other tool is pressed against the blank by progressively increasing pressure medium pressure with a force that is initially less than the force of the clamping member and then greater than the force of the clamping member. υ he OWGiNAL INSPECTED ^bn 909850/0030 - 11 -