US2360771A

US2360771A - Bucking bar for tubular members

Info

Publication number: US2360771A
Application number: US469321A
Authority: US
Inventors: Alfred H Haberstump
Original assignee: Murray Corp
Current assignee: Murray Corp; Murray Corp of America
Priority date: 1942-12-17
Filing date: 1942-12-17
Publication date: 1944-10-17
Anticipated expiration: 1961-10-17

Description

OC' 17, 1944- A. H. HABERSTUMP -BUCKING BAR FOR TUBULAR MEMBERS Filed Dec. 17, 1942 Y HZfreJ/Y Haier Patented Oct. 17, 1944 VBUCKING BAR FOR TUBULAR MENEBERS Alfred H. Haberstump, Detroit, Mich. assigner to The Murray Corporation of'America, Detroit, Mich., a corporation of Delaware Application December 17, 1942, Serial No. L169,321

9 Claims.

This invention relates to bucking bars and particularly to a new and novel bucking bar employed for bucking arivet on the inside of tubular elements.

When the rivets which extend through the wall of a tubular'element of small 'diameter are to be bucked, diculty has been experienced in positioninga dolly within the element in position to engage and buck the rivet. Especially is this true when the rivets have their heads on the outside of the tube and are driven from the outside in the manner employed in the aircraft industry. While some types of bucking bars have been heretofore constructed to back the rivets which extend through a tubular wall, these, as far as applicant knows, are not entirely suc` cessful because of the fact that the same reaction is not obtained at all points throughout y the length of the bar.

Following the teaching of the copending application to A. H. Haberstump, Serial No. 440,837, led April 28, 1942, and assigned to the assignee of the present invention, the bucking bar of the present invention is supported in parallelogram relation to the base so that the same reaction is obtained at all points throughout the bar length. The bar may span `any number of rivets and the entire number is swaged without the necessity of moving the bar from one rivet to another as the same reaction'will obtain at all points along the bar. This is necessary when employing a, timing device on the percussion hammer such as that illustrated and described in the copending application of A. H. Haberstump, Serial No. 439,115, led April 15, 1942, and assigned to the assignee of the present invention. This timing device controls the number of strokes struck by the hammer during the cycle and when bucked in they same manner identical bucktails willbel swag'ed on the ends of'all of the rivets being driven. If the bar would react differently at `points throughout its length, it Ywill be readily apparent that diierentswaging operations would be performed on the vrivets when struck the same number of times" andthe bucktails produced engagement with the inner wall of thevtube. Onl-y suicient pressure is employed when'raising-thef'bar so that it may be deected by# a rivet-when forced downwardly by: the operator when applying the riveting hammer to the rivet head As the hammer operates, the-'impact is applied through the rivets tothe barv which swages the end as the bar' is-maintained against the rivet by the applicationl of the force on one of its ends. The cylinder is connected to a flexible conductor by which the bucking bar is advanced along the wall. Air is introduced into thecylinderthroughthe conductor to'moVe-/the piston outwardly for Amoving and holding` the bucking bar against thel wall of the tube-ortho rivet ends. When the rivet is forced downwardly to have its head engage the surfacev of the outer element to be riveted, the bar is deflected against y the piston Awhich isforced back against theA pressure in the cylinder.

Accordingly, theA main objects of this inventionrare:y to provide a bucking bar for a` tube having a base element and a buckingelement in parallel relation toeach otherinterconnected by parallel links which are in pivotal relation therewith'and manipulate the baron the links with a piston in aligned relation with the bar; to form a bucking bar 'from a base element which is a channel-shaped stamping having bosses for pivoting links on which a solid bucking bar is pivote'd and'lcontrolled by a piston and cylinder mounted' on the end of the base to whichfpres'- sure is delivered by a flexible conductor by which theb'ucking bar is manipulated in a tube torbe riveted; to construct a compact bucking bar from a channel element and a T-shaped bar which are interconnectedby a pair of links to produce parallelogram relationship therebetween andv provide a flexible conductor at the end "of the bar for applying pressure thereto; and in general to 'provide acompact buckingv bar which is `in sertable within a tubular element of small diam- `eter,'which is simple in construction, positive'in in Figure 1, with parts in section and with the bar in raised operating position;

Figure 3 is a sectional view of the bucking bar illustrated in Figure 1, taken on 4the line 3 3 thereof; and

Figure 4 is a sectional view of the structure illustrated in Figure l, taken on the line 4-4 thereof.v Y

The bucking bar embodies a base element I which is of channel section having bosses Il welded or otherwise secured near opposite ends thereof. The forward end of the bar is arched upwardly at I2 while the rear end is extended at I3 and flanged upwardly at I4 lto form a rear wall having an aperture I5 therethrough. A pair of links I6 are pivoted at one end to the bosses II,by the pins I1 while the opposite ends are pivoted by the pin I8 to the bucking element I9. The element I9 is provided with recesses 2I for receiving the links and cutaway portions 22 and 23 for receiving the bosses I I.

The bucking element I9, as illustrated in Figs. 3 and 4, is T-shaped in section having an enlarged head 24 which engages the rivets. The element I9 is retained at all times parallel to the base element I0 because of its support on the links I6 and will produce the same reaction in the central as well as the overhanging end portion thereof. The same reaction is obtained for swaging the bucktails on the rivets at all points throughout the bar length as when the hammer is operated on a predetermined time cycle assurance will be had that all of the bucktails formed on the swaged rivets will be exactly of the same diameter and thickness.

vFor applying resilient pressure to the bucking bar while retaining the bar compact so as to be insertable in a tubular element of small diameter, a cylinder 25 having a threaded stem 26 is mounted in the extending end portion I3 of the base element I0 with the threaded stem extending through the aperture I5 and secured in position by a nut 26. iA hose connector 28 is threaded within the stem 26 and a hose 29 is secured thereto by suitable means, herein illustrated as by a clamp 3|. A piston 32 extends within the cylinder 26 and is sealed thereto by a sealing cup 33 of conventional form which is retained in position by a washer 34 and a screw 35. The outer end of the piston 32 has an arcuate head 36 which provides point engagement with vthe end of the bucking element I9 which permits the bucking element to move across the head without material resistance. It is to be understood that while the piston herein illustrated is to be operated by fluid pressure, that a spring could be employed within the cylinder 25 for operating the piston, the tension on which may be applied by the movement of a wire or rod through the hose 29.

In Figure 1, the bucking bar is illustrated with the piston retracted within the cylinder 25 and the bucking element I9 moved downwardly onto the base element I0. In this position, the bar is readily inserted within the tubular element, such as 31, to which an element 38 is to be riveted. After the bar has been `inserted sufficiently to engage a plurality of the rivets, air is applied to the cylinder 25 through the hose 29 to move the piston to the left, as viewed in the ligure, to thereby move the bucking element I9 upwardly on the links I6 into engagement with the inner surface of the tubular element or to the bucktail of rivets which have already been driven.

A rivet, such as 39, is inserted in an aperture through the elements 38 and 31 and the driving dolly 4I of a riveting hammer is placed against the head of the rivet forced downwardly to push the head of the rivet into engagement with the outer surface of the element 36. This deects the bucking element I9 which reacts against the piston 32 to move the piston against the pressure of air within the cylinder 25. As the driving hammer is operated, the impact applied to the rivets causes the end thereof to become swaged as the bucking bar is constantly urged against the end thereof, so that after a predetermined time cycle a bucktail 42, such as that illustrated in Fig. 2, is formed on the end of the rivet.

All of the rivets which can be spanned by the bucking element I9 are driven in this manner and like bucktails 42 will be formed on all of the ends thereof because of the exact reaction to the bucking operation by the bucking bar at all points along its length. Thereafter, pressure is removed from the cylinder 25 permitting the piston 32 to retract as the bucking element I9 moves downwardly upon the base element I0. The bucking bar may be moved further within the tube thereafter to span an additional group of the rivets to be swaged. Air will again be applied through the hose 29 into the cylinder 25 to again advance the piston and the bucking element I9 into engagement with the inner surface of the tubular element 31. By marking the hose 29, the position of the bucking bar I0 on the inside of the tube can readily be ascertained and the bucking bar can be accurately located in this manner.

What is claimed is:

1. A bucking bar comprising, a base element, a pair of links pivoted to said base element, a bucking element pivoted on the end of the links, a cylinder supported by the base element in aligned relation to said bucking element, and a piston in said cylinder in abutted engagement with one end of the bucking element.

2. A bucking bar comprising, a base element, a pair of links pivoted to said base element, a

bucking element pivoted on the end of the links,

a Cylinder supported by the base element in aligned relation to said bucking element, a piston in said cylinder contacting the bucking element, and a flexible hose connected to the cylinder.

3. A bucking bar for a hollow tube including, a base element of channel section, bosses provided within the' channel element, links pivoted to said bosses, a bucking element supported within the channel on the pair of links, a cylinder supported by the channel element beyond one end of the bucking element, and a piston within said cylinder movable into engagement with the end of said bucking element.

4. A bucking bar for a hollow tube including, a base element of channel section, bosses provided within the channel element, links pivoted to said bosses, a bucking element supported within the channel on the pair of links, a cylinder supported by the channel element beyond one end of the bucking element, a piston within said cylinder movable into engagement with the end of said bucking element, and a flexible uid conductor secured to the end of the cylinder for conducting pressure thereto and'for manipulating the bucking bar within the hollow tube.

5. A bucking bar for a tubular element embodying a base element -comprising a stamping of channel section having an upwardly arched front end portion and an upwardly extending rear portion having an aperture, a cylinder in the rear portion having a hollow extending stem projecting through said aperture and secured thereto, a T-shaped bucking bar having recessed portions, a pair of links each pivoted within a recess, pivots for interconnecting the opposite ends of the links to the base element, and a piston within said cylinder for operating the T-shaped bucking element.

6. A bucking bar for a tubular element em- .bodying a base element comprising a stamping of channel section having an upwardly arched front end portion and an upwardly extending rear portion having an aperture, a cylinder in the rear portion having a hollow extending stem projecting through said aperture and secured thereto, a T-shaped bucking bar having recessed portions, a pair of links each pivoted within a recess, and a piston within said cylinder having an arcuate end which abuts against the end of the bucking element.

7. A bucking bar for a tubular element embodying a base element comprising a stamping of channel section having an upwardly arched front end portion and an upwardly extending rear portion having an aperture, a cylinder in the rear portion having a hollow extending stem projecting through said aperture and secured thereto, a T-shaped bucking bar having recessed portions, a pair of links each provided Within a recess, a piston within said cylinder having an arcuate end which abuts against the end of the bucking element, and a flexible conductor secured to the end of the cylinder for conducting air to the piston and for manipulating the bucking bar within the hollow tubular element.

8. A bucking bar embodying a base element which is a channel-shaped stamping, spaced links supported on said base element, a bucking element pivoted on said links to provide a parallelogram relationship between the bucking element and the base element, and resilient means supported at one end of the base element in alignment with said bucking element for urging the bucking element upwardly on the links and provide a predetermined pressure thereto.

9. A bucking bar embodying a base element which is a channel-shaped stamping, spaced links supported in said base element, a bucking element pivoted on said links to provide a parallelogram relationship between the bucking element and the base element, resilient means supported at one end of the base element in alignment with said bucking element for urging the bucking element upwardly on the links and provide a predetermined pressure thereto, and a flexible extension on said bucking bar through` which the pressure on said bucking element is adjusted.

ALFRED H. HABERSTUMP.