US2496330A - Riveting equipment - Google Patents

Description

Flb. Y, T195@ M. BROWN 295y33 RIVETING EQUIPMENT Filed June 2, 1944 3 Sheets-Sheet l Feb. 1195@ M. BROWN ,496,330

RVETING EQUIPMENT Filed June 2, 1944 5 Sheets-Sheet 2 il j@ I Il llll 5/ 1 mmm -f i m lill Flb. W5@ M. BROWN RIVETNG EQUIPMENT 3 Sheets-Sheet 3 Filed June 2, 1944 Patented Feb. 7, 1950 UNITED STATES PATENT OFFICE RIVETING EQUIPMENT Morris Brown, San Diego, Calif.

Application June 2, 1944, Serial No. 538,355

(Cl. 7S-53.5)

Claims.

The invention relates to improvements in equipment for riveting.

In riveting together parts, such as sheets, or sheets and structural members such as stringers and sheets, for aircraft panels, a great multiplicity of rivets is necessary. In many instances the rivets must be xed in non-symmetrical rows, rivets of different sizes must be used, and clusters of rivets are required in certain areas of a panel or structure, depending upon the stress concentrations or location of the strlngers in dierent areas of the panels. The panels in many instances are differently shaped or of dilerent contours and the stringers are non-symmetrically located on the panels. Heretofore, so far as I am aware, it has been necessary in structures embodying such variables or variations to use a power-operated hammer handled by an operator on one side of the panel and a bucking tool handled by another operator on the opposite side of the panel. In some structures there is little space available for the manipulation of the bucking tool, which slows down the riveting operation. If the hammer is erroneously applied to rivets in the absence of a bucking tool, the work may be objectionably deformed.

One object of the invention is to provide equipment which comprises an elongated bucking-bar for automatically upsetting the rivets in a row or series and dispensing with the necessity of an operator for handling the bucking tool during the riveting of the row or series of rivets.

Another object of the invention is to expedite the riveting operation by a bucking element to which counter blows are imparted reactively to blows received through the rivets from a poweroperated hammer, by damping the vibrations of the bucking element or restraining its movement with the anvil.

A still further object of the invention is to provide equipment which, by variations of the face of the bucking-bar engaged by the rivets, can be adapted for automatically bucking rivets of different sizes or clusters.

Another object of the invention is to provide an automatic bucking device which is simple in construction and eflicient in operation.

Other objects of the invention will appear from the detailed description.

The invention consists in the several novel features hereinafter set forth and more particularly dened by claims at the conclusion hereof.

In the drawings:

Fig. 1 is a side elevation of an apparatus equipped with a series of bucking devices ernbodying the invention, parts being broken away for illustrative purposes.

Fig. 1a is a horizontal section through the fixture illustrating one of the bars for bucking a row of rivets of different sizes or lengths.

Fig. 2 is a section taken on line 2-2 of Fig. 1.

Fig. 3 is a horizontal section illustrating one of the bucking devices for a row of rivets of the same length.

Fig. 4 is a section taken on line 4-4 of Fig. 3.

Fig. 5 is a section taken on line 5-5 of Fig. 3.

Fig. 6 is a perspective of one of the carriers which are mounted on the vertical members of the fixture, for slidably supporting one end of the bucking-bar, and means for damping the vibrations of the bucking-bar.

Fig. 7 is a perspective of one of the adjustable bars for supporting one of the damping elements.

Fig. 8 is a perspective of one of the gauge-bars.

Fig. 9 is a perspective of the bucking-bar illustrated in Fig. 1a.

Figs. 10 and 11 are perspectives of different forms of bucking-bars.

The bucking devices are adapted to be mounted in a rigid fixture which is provided for supporting the components of a panel for use in aircraft which are to be riveted together. This xture may comprise a heavy rigid rectangular frame I2 which may be formed of tubing and is fixed to columns I3 which are usually embedded in a concrete floor I 4 for rigidly securing the frame. A series of rigid vertical bars I5 extend between and have their ends welded to the top and bottom members of frame I2. Bars I5 are utilized to support the automatic bucking devices in the frame and also for supporting the work in cooperative relation with said devices. The front faces I6 of the vertical bars I5 are shaped to engage the sheets a of the panel which are usually curved, and notches II are formed in said bars "for receiving the structural members, such as stringers b which are to be riveted to the sheets a of the skin-forming aircraft panel. The assembled sheets and stringers for a panel are secured and positioned on the frame I2 by metallic straps I9, the upper ends of which are adjustably secured at 20 to the top member of the frame I2 and the lower ends of which are secured to the lower member of frame I2 by lsuitable lever operated clamps 2I whereby the straps may be tensioned to clamp the sheets of the panel against the front faces of the bars I5. This frame exemplifes a rigid xture whereby an assembly of sheets and stringers can be rigidly supported while al1 of the riveting operations necessary for the panel are performed by one or more power operable hammers, in coaction with bucking devices which are supported in the fixture.

A series of bucking devices are supported on the vertical members I5 of the frame I2 at the back of the panel-assembly and each of these devices comprises a bucking-bar, generally designated 22. Each bucking-bar is adapted for upsetting all of a row or group of rivets, and collectively these devices are adapted for upsetting substantially all of the rivets for securing together the components of the panel. Each bucking-bar is positioned conformably to a row or group of rivets. These bars may be non-symmetrically arranged according to the areas in the panel to be riveted, may be provided with extensions for riveting clusters of rivets, may be formed of masses of different weight for rivets of different sizes, and may be arranged angularly relatively to one another, all according to the structural requirements of a panel used in aircraft, so that substantially all of the rivets for the panel can be upset in one setting of the panel-assembly on the fixture. The bucking-bar shown in Figs. 3, 4 and 6 is provided with an elongated straight face 22 which is adapted to be engaged by the inner ends of the shanks of a row of rivets c (Fig. 3) which are inserted through the work. The pre-formed rivet heads are engaged by a power operable hammer d to cause the bucking-bars to upset a head on the inner ends of the rivets.

Each bucking-bar is slidably supported by a pair of carriers, one at each end of the bar, which permit the bar to slide angularly when either end portion of the bar is engaged by a rivet, or rectilinearly when engaged by a rivet along the longitudinal center of the bar. These carriers are alike in construction. These carriers, generally designated 23, are each supported from a vertical frame member I5. Each carrier 23 is supported from one of the vertical frame bars I5 by an angular bracket 28, the vertical ange 29 of which is secured by bolts 30 to one of the vertical frame bars I5. The lower plate 25 of each carrier 23 is transversely notched as at 32 to t on a pin 33 which is welded to the top of the bracket 28 and the carrier is held in 4engaged relation with said pin by a pair of studs 34 which extend vertically through the carrier and are provided with nuts 35 which engage springs 36 to hold the carrier seated on the bracket 28. The studs 34 and springs 36 provide a pivotal connection between the carrier and the fixed supporting bracket 28 which permits the slidable bucking-bar to be slightly tilted vertically. In practice, this connection between the carrier and bracket 28 permits the buckingbar 22 to be deected to position it to compensate for slight deformations in the stringers b or tolerances in the location of the rivet-holes.

Each carrier 23 is equipped with spring-pressed means for imparting counter blows to the bucking-bar reactively to the blows of the hammer. This means is exemplified by an anvil 31 on a stem 38 which is slidably mounted in the block 26 and a spring 39 between block 26 and the anvil 31. A pin 40 in the inner end of stem 38 retains the anvil 31 and spring 39 in the carrier when the bucking-bar is removed. Each carrier 23 is provided with a gauge-bar 42, with an inwardly extending lip 43 which laps the face 22' of one end of the bucking-bar, and limits the movement of the bucking-bar toward the work for limiting the thickness of the upset heads by rendering the bucking-bar ineiective when it enthe bucking-bar toward the Work and determines the thickness of the upset on the rivets. The gauge-bar 42 is confined vertically between the plates 24 and 25 and laterally slidable between the blocks 26 and 21 and the contiguous face of the frame bar I5. A lip 44 on the inner end of the gauge-bar 42 retains the gauge-bar in the carrier. During the operation the bucking-bar is pressed inwardly by a rivet when it is engaged by the riveting hammer, and the blows imparted to the outer end of the rivet'fwill be transmitted through the rivets to the bucking-bar. The spring-pressed anvil 31 will receive impact blows from the bucking-bar which will move the anvil against the force of spring 39 away from the bucking-bar until the rivet has been upset within the limits permitted by the lip 43 of gauge-bar 42. The mass in the bucking-bar and in the anvil and the force of the spring 39 are co-related to produce these counter blows.

In practice, it has been found that undamped vibrations of the bucking-bar reduce the effectiveness of the anvil in imparting counter `blows to the bucking-bar and slow down the upsetting of the), rivet, and the invention contemplates dampin these vibrations. For this purpose, each carriens' 23 is provided with a damping element which 'is i exemplified by an elastic block or mass 46 formed of rubber. This block or mass is held in an outstruck tongue 41 on a bar 48 which is adjustably secured to the carrier by screws 49 which extend through slots 50 in bar 48 and are threaded into a block. One end of the element 46 abuts against an outstruck shoulder 5I on bar 48` and s its outer end is engaged by the bucking-bar.

mer d to the bucking-bar.

gages the lip 43 which limits the movement of When the bucking-bar is forced away'from the work by a rivet, as illustrated in the lower portion of Fig. 3, the elastic mass 46 will be compressed between the bucking-bar and shoulder 5I. This elastic mass, when compressed, exerts pressure against the bucking-bar and toward the rivets independently of the force of spring 39 and damps the vibration of the bucking-bar. The anvil 31, when struck by the bar, compresses the f spring 39 and rebounds from the bucking-bar and the spring 39 operates the anvil to impart the counter blows with substantially the same effect as if hammer blows were imparted to the anvil by a riveting hammer. The elastic mass 46 damps the vibration and also restrains the bucking-bar so that the latter will not follow the strokes of the anvil against its spring 39 and permits the full force of the spring-imparted strokes of the anvil to be utilized with counter blows reactively to blows imparted through the rivets by the ham- In practice, it has been found that this damping and restraining of the bucking-bar causes it to more expeditiously upset a rivet than when a hand manipulated bucking tool is used. When the bucking-bar is initially moved inwardly by a rivet to which the hammer d is applied, the spring 39 and the damping mass 46 will be compressed. The spring will cause the bucking-bar to follow up the rivet as the upset head is formed thereon and the damping element 46 will remain effective until the upset is completed. During each riveting operation, the gauge-bar 42 determines the thickness of the head which will be upset on the rivet shank. When the head is formed, the gauge-lip 43 will hold the bucking-bar spaced from the work a distance equal to the thickness of the upset head on the rivet. A distinct change in sound occurs when the bar strikes the gauge-bar engaging the work,

and this indicates to the operator that the upset head is completed.

Each bucking-bar is adapted for upsetting a series or row of rivets. When all of the rivets in a row are of the same size and length, the bucking-bars are provided with straight faces 22 as illustrated in Figs. 3, 4 and 6. The work to be riveted may be of different thickness. Rivets of different lengths may be necessary, as illustrated in Fig. la, where three sheets are riveted together in one portion of the panel, or two sheets .may be riveted together in a portion of the panel, or one of the sheets of metal may be tapered in thickness. These varying requirements are met by modifications in the rivetengaging faces on the bucking-bars. Where a group of rivets is extended through a portion of the work having an inclined thickness, as illustrated in Figs. 1a and 9, the bucking-bar is provided with an inclined face 22a. of different thickness with heads of different thickness are necessary, the rivet-engaging face of the bar is longitudinally stepped as at 22h, 22C and 22d, as illustrated in Figs. 1a and 9. The face portion 22b is spaced from the work to form the head on a thick rivet; the face portion 22C is spaced from the work to form thin heads on the rivets; and the face portion 2l!d is spaced from the work to form heads of intermediate thickness. In some instances a cluster of closely arranged small rivets is necessary in an area of the panel. The face of the bar may be of sufcient width for this purpose or the face may be extended by pads 22e, 22f and 22g, as illustrated in Figs. 1 and 16. In constructions where the rivet-engaging faces of the bar are stepped or inclined, gauge ribs 42EL are provided which determine the thickness of the heads which are upset by that bar. In some instances the rows of rivets must be angled relatively to one another, and for riveting such rows the portions of the bucking-bars between their ends are inclined as illustrated at 22h in Figs. 1 and 11.

Each of these different forms of bucking-bars has its ends slidable in a pair of carriers 23 which are supported in the fixture independently of the others, These bars make it possible to meet the requirements in riveting composite panels, such as those used in aircraft, in which the rows of rivets are non-symmetrically arranged in different areas of the panel, rivets of different thickness and length may be upset, for completing substantially all of the riveting necessary during a single setting of the assembled work on the fixture.

In these various bucking devices, bars of different weights may be used according to the thickness of the rivets which are to be bucked. The mass or weight of the bucking-bars is corelated with the weight of the anvil and the force of the springs for shifting them. In some instances, pneumatic hammers with impacting elements of different force are used for upsetting rivets of different thickness. This co-relation has been found to be readily determinable by trial and providing anvils of suitable weights vor masses and springs 39 of suitable magnitude to produce effective counter blows against the bucking-bar for different kinds of work when the vibrations of the bar are damped by a resilient mass 46, The vertical frame-bars l5 may be provided with holes 50b and the brackets 28 with slots 56a for the screws which secure the bracket 28 to bars I5 for mounting the bucking devices in different positions in the frame I2.

Where rivets The operation of the riveting equipment is as follows: After the bucking devices have been installed in the fixture in accordance with the location of the rivets to be upset, the components of the panel, consisting of sheets or sheets and structural members, such as stringers for the desired panel, will be assembled on the front faces of the vertical frame member l5 with the rivet holes in the components to be riveted together coaxially disposed and so that the bucking-bars will be positioned in back of the rivet holes in the panel and fixedly secured on the frame members l5 by straps i9. The rivets inserted in all of the holes are usually temporarily held therein by a strip of tape (not shown). A power operated hammer d, is then successively applied to any of the rivets. As the hammer is applied to any rivet, the latter will force the bucking-bar rearwardly against the force of the spring 39 applied to the nearest anvil 31 andl the damping element 46 associated with said anvil will be compressed. The ends of the bucking-bar being slidable in the carriers, at least one of the spring-pressed anvils 3l will be shifted against the force of its spring 39 and the associated `damper 46 to be compressed while the other end of the bar may remain static. As the hammer is operated, the bucking-bar Will upset the head on the inserted end of the rivet. During the continued operation of the hammer, the shifted anvil will impart counter blows to the bucking-bar reactively to the hammer blows while the vibrations in the bucking-bar are damped by the associated damper 46, and said bar will follow the rivet-end as it is upset until the bucking-bar and gauge-lip i3 arrest the movement of said bar toward the rivet, which determines the thickness of the upset head on the rivet. In practice, it has been found that when the vibrations in the bucking-bar are damped or it is resiliently restrained from following the movements of the anvils, the mass in the anvils 3l and the force of springs 39 can be co-related to the bucking-bar to cause the hammer blows and the counter blows to be measurably synchronized and produce an effect similar to that produced when blows in counter directions are simultaneously applied to the rivet, and this results in greatly expediting the upsetting of the rivets. The bars i8 which support the damping elements are adjustable on the carriers, so they can be set to effectively damp the vibrations of the bar and restrain, 1n desired degree, its movement while transmitting blows to the anvils. As the hammer is applied to successive rivets in a row or group in front of the bucking-bar, one or the other or both of the anvils 31 and damping means 46 will be effective against the bar during the successive operations of the hammer. A characteristic of this apparatus is that a bucking-bar is always present in back of a row of rivets. When a manually held bucking tool is used it frequently occurs that the operator of the hammer on one side of the work Will, through error, apply the hammer to a rivet while the bucking tool is not manually held against it, which results in dimpling or deformation of the Work when skinforming panels are fabricated. of the bucking-bars for a row of rivets in the panel effectively reduces the likelihood of this deformation. It is also possible for several,

operators to simultaneously apply hammers to rivets in different portions of the panel to expedite fabrication. When stringers b are being The presence.

riveted to sheets, slight deviations or irregularities occur. The pivotal and spring connection between the carriers 23 for the bucking-bars and the brackets 28 permit the bucking-bar to be shifted vertically to compensate for these variations or deviations.

The invention exemplies riveting equipment which includes an elongated automatic buckingbar which is supported at its ends in a xture for quickly upsetting of rows or groups of rivets. The invention also exemplifies a bucking device which is provided with a spring-pressed anvil for imparting counter blows to the bucking element and which is provided with means for damping the vibrations of the bucking element or restraining it from movement with the springpressed anvil. The invention also exemplies bucking equipment which is adapted for the ready substitution of bars having faces for engaging dilerent rivets or rivets in differently arranged groups and rows. The invention also exemplifies a bucking device for expeditiously upsetting rivets in coaction with a power-operated hammer.

The invention is not to be understood as restricted to the details set forth, since these may be modied within the scope of the appended claims without departing from the spirit and scope of the invention.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

l. Apparatus adapted for use with a powercolumns for /slidablyqand separately supporting the ends di each of the buckin'g`ba'rs and on which the ends of each bar are freely supported for angular deflection by impact blows, and devices for each end of each of the bars, carried py said supporting members, for imparting counterblows independently to the ends of each bucking bar reactively to impact blows imparted to the bars.

2. Apparatus adapted for use with a poweroperated hammer for riveting assembled elements together comprising: a rigid upright frame extending over substantially the entire area of a panel assembly which is to be riveted and includes a sheet, columns rigidly supported in the frame, means for clamping parts of the assembly against the columns, bucking bars extending between the columns for series of rows of the rivets to be upset in substantially the entire sheet, a pair of spaced members on the columns for slidably and separately supporting the ends of each of the bucking bars and on which the ends of each bar are freely supported for angular deflection by impact blows, said members being mounted on the columns for pivotal movement transversely of the bars, and devices for each end of each of the bars, carried by said supporting members, for imparting counterblows independently to the ends of each bucking bar reactively to impact blows imparted tol the bars.

3. Apparatus adapted for use with a poweroperated hammer for riveting assembled elements together comprising: a rigid upright frame extending over substantially the entire area of a panel assembly which is to be riveted and includes a sheet, columns rigidly supported in the frame, flexible strips for clamping parts of the sheet against the columns, bucking bars extending between the columns for series of rows of the rivets to be upset in substantially the entire sheet, a pair of spaced members on the columns for slidably and separately supporting the ends of each of the bucking bars and on which the ends of each bar are freely supported for angular deection by impact blows, and devices for each end of each of the bars carried by said supporting members, for imparting counterblows independently to the ends of each bucking bar reactively to impact blows imparted to the bars.

4. Apparatus adapted for use with a poweroperated hammer for riveting assembled elements together comprising: a rigid upright frame extending over substantially the entire area of a panel assembly which is to be riveted and includes a sheet, columns rigidly supported in the frame, means for clamping parts of the sheet against the columns, bucking bars extending between the columns for series of rows of the rivets to be upset in substantially the entire sheet, a`pair of spaced members on the columnsv for slidably and separately supporting the ends of each of the bucking bars and on which the ends of each bar are freely supported for angular deflection by impact blows, spring-pressed anvils for each end of each of the bars carried by said supporting members, for imparting counterblows independently to the ends of each of the bucking bars reactively to impact blows imparted to the bars, and means adjacent the ends of each bucking bar for damping vibrations in the bar.

5. Apparatus adapted for use with a poweroperated hammer for riveting assembled elements together comprising: a rigid upright frame extending over substantially the entire area of a panel assembly which is to be riveted and includes a sheet, columns rigidly supported in the frame, bands extending over the columns for clamping parts of the sheet against the columns, bucking bars extending between the columns for series of rows of the rivets to be upset in substantially the entire sheet, a pair of spaced members on the columns for slidably and separately supporting the ends of each of the bucking bars on which the ends of each bar are freely supported for angular deiiection by impact blows;l and spring-pressed devices for each end of each of the bars carried by said supporting members, for imparting counterblows independently to the ends of each of the bucking bars reactively to impact blows imparted to the bars.

MORRIS BROWN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 180,269 Reardon July 25, 1876 201,750 Clements Mar. 26, 1878 264,630 Cook Sept. 19, 1882 (Other references on following page) Number Number Name Date Goldstein Aug. 1, 1944 Haberstump Oct. 17, 1944 Haberstump Mar. 19, 1946 Haberstump Apr. 9|, 1946 Brown Oct. 12,4948

FOREIGN PATENTS Country Date Great Britain Oct. 5, 1916

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