US2313843A - Riveting tool - Google Patents

Description

March 16, 1943. E. H. silAFF yRIVETING TopL Filed Nov. 4, 1937 .Hmm E@ (/ITroQyEzy/S III l@ 2, @i N for adjusting the rivet Patented Mar. `16, 1943 UNITED STATES PATENT OFFICE 2,313,843 l alvE'rrNG roof.

Y Ernest H. Sham Grand Haven, Mich., assigner to William H. Keller,

Inc., Grand Haven, Mich., a corporation 'of Michigan Applicaties November 4, 1937, serial No. 172,681

7 Claims.

This invention relates to improvementsin riveting tools and more particularly concerns yoketend to limit the invention to the speciiic forms' lust as eil'ective to increase the power ratio be. I

tween the force of the piston thrust and the compression force of the ram and which operates in a more emcient and simplified manner.

Another object resides in the provision of novel means for entirely relieving the driving `piston assembly of side .thrust during operation.

Another object is to provide limproved means for governing the pressure iluid actuated driving piston assembly to operate the `ram selectively through a complete working cycle including a compression stroke and an instantaneously succeeding return stroke.

Another object is vto provide a novel yoke-type riveting tool including a unique, unusually cornpact and powerful operating arrangement of the ram, rivet sets and driving means permitting the tool tobe used in places having very limited working room.

Another object is to provide improved means sets.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings in which:

Figure l is a fragmentary elevational view,.

partially in axial section of a riveting tool embodying features of the invention.

Fig. 2 is a fragmentary axial sectional view of the .I rear portionl of the tool, showing certain parts in the relative positions assumed at' the end of the power stroke in the cycle of operation.

Fig. 3 is a fragmentary sectional view taken along line 3-3 oi' Fig. 1.

Fig. 4 is a diagrammatic elevational view illus- Vtrating the operationof the driving link between the ram and' the piston rod. n

Fig. 5 is a sectional elevational view partly in axial section of a modified form of 'the invention.

While the invention is susceptible of various A 'modifications and'alternative` constructions, I

have shown in the drawings and will herein de- "scribe in detail. the preferred embodiments, but it is tol be understood that I do vnot thereby indisclosed, but intend to cover all modifications' and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

One form of the invention selected for the v purpose of illustration (Fig. 1) includes an elongated, chambered housing or barrel I0 near one end of which is a conventional riveting yoke II having one arm anchored rigidly between'spaced parallel ears I2 projecting laterally of the barrel. The outer arm of the yoke carries an ad- Justable, stationary anvil or rivet set I3, while the attached arm of the yoke has a bore I4 in the forward end thereof serving as lthebearing guide for an elongated reciprocal compression ram I5 carrying a rivet set I1. The ram has an inner end or base portion'is preferably of rectangular cross-section which slides within a suitable forwardly opening recess IS formed within a reduced front nose portion 20 upon the barrel III. A closure plate 2| is bolted over the recess I9 and serves as a bearing for the base portion I8 ofthe ram. i

Power for driving the ram I5 is generated by any Vsuitable driving means, such means being shown herein as comprising a suitable pressure fluid actuated piston assembly, including a pair of pistons 22 and 23 arranged in tandem and reciprocably mounted within partitioned front and rear piston chambers 24 and 25, respectively, in the barrel I0 on an axis which herein is at substantially right angles toy the path of movel mentof the rain I5. The pistons have a common axial plunger or piston rod 21 which extendsv beyond the front piston 22 a suilicient, distance to underlie the base I8 of the ram I5 when the pistons are in forward position.

By the present invention the ram base I8 is connected to the forward end of the piston rod 21 without the toggle link assembly heretofore conventionally employed for this purpose. Here,- in, slots 28 and 29, respectively, are provided in a common axial plane in the base I3 and the forward end of the piston rod 21 to provide bifurthe medium of the link 30, simultaneously initiate movement of the ram in the compression stroke without undue side thrust upon the base I8 of theram, such slight side thrust vas may arise being absorbed by the closure plate 2i acting as a bearing.

As the pistons move forwardly and the rarn i moves outwardly in the compression stroke, the inclination of the driving link 30 gradually increases relative to the axis of the piston rod 2l, until at the end of the forward stroke the link extends almost perpendicularly to said axis. Coincident with such change in inclination ,of the driving link, there is a gradual change in the relative distances of travel of the pistons and the ram l5, the ram traveling substantially twice as far as the pistons during the-first quarter of the compression stroke and only about onev fourth as far as the pistons during the last quarter of the compression stroke. This change is graphically illustrated in Fig. 4, where the distance traveled by the pistons, using the axis of the pivot pin 32 as a center, has been shown as divided into four equal steps, A,.B,' C, and D; and the corresponding distances traveled by the ram I5, using the axis of the pivot pin 3| as a center, has been shown as divided into four steps A', '.B', C', and D. In this manner, while the driving force and the speed of the pistons remain constant throughout the power stroke, the speed of the ram, although greater at the beginning of its Ycompression stroke will gradually decelerate with a directly proportional increase in compression, exerting in the inal position of the compression stroke a force about four times as great as the forward thrust of the pistons.

As the ram l5 exerts increasing compression upon the rivet, there is an equal and opposite back pressure only a fraction of which is absorbed by the` forward thrust'of the pistons, the remainder being transmitted as a side thrust to the piston rod 21 tending to distort the same off center. Means is therefore provided by the present invention for relieving the piston rod 2l of such distorting force, such means herein `comprising a cylindrical bearing bore 34 in the forward nose portion 20 coaxial with and slidably receiving the bifurcated forward end of the piston rod. Preferably the bore and rod are shaped cylindrically.

Since the principal thrust is always toward the side of the piston rod 21 opposite the ram I5, there will be a tendency toward greater wear on this side. To avoid such wear',however a hardened metallic thrust plate 35 formed as a chordal section -of the bore 34 is secured in place as by a bolt 31 to engage the thrust side 'of the piston rod which is formed with a flattened bear ing face 38.

Preferably means is provided to avoid frictional resistance between the thrust plate 35 and l the piston rod bearing face'v 38 as the thrust pressure increases, herein including a pair of rollers 35 mounted one on either side of the link 3@ with the pivot pin 32 as an axle. The diameter of the rollers is such as to carry the peripheries almost flush with but slightly beyond the bearing face 35 of the piston rod to ride upon the thrust plate during at least the last part of the power stroke of the pistons. Thus, there will be a minimum of power loss due to friction even through great. pressures and side thrust may be generated in operation. Moreover, the piston assembly will be maintained entirely free of side thrust distortion and wearmg of the vparts will be kept to a minimum.

Another feature of the invention resides in an improved operation controlling and governing system' for 'the tool, including a pressure :duid

asiasss control valve mechanism 4`which is selectively manually operable, and an automatic piston-operation-cycle governor 4l. The valve mechanism and governor operate in series'between the 5 source of motivating pressure iiuid supply and the piston chambers 24 'and 25.

The control valve mechanism 4!! (Fig. 2) is of the type which will not only permit the passage of live motivating pressure fluid such as compressed air to actuate the driving pistons but will' also relieve the piston actuating system of any remaining pressure iiuid at the end of Aa working cycle. Said valve mechanism is therefore constructed as a self-contained unit housed within an axially bored casing Q2, one end of which is closed by a screw vplug d3. Pivotally mounted uponthe opposite end of the casing is a rearwardly extending operating handle lever de which intermediate its end engages the outer end of an inwardly movable plunger d5. The plunger is slidably mounted within a fixed sleeve bushing il which at its inner end coacts with a valve member d3 held sealingly thereagainst by a compression spring d. When the valve d8 is forced open by pressing the handle against the end of the plunger d5, pressure iluid delivered from a suitable source through a conduit 5B and an inlet .port 5l will pass to the interior of the bushing di. Thence the pressure fluid passes through a generally radial series of apertures 52 into a peripheral groove 53 which communicates with an outlet port 5d.

Any back pressure in the system ahead of the valve i8 when closed is vented to atmosphere,

the plunger 45 being constructed to form a relief valve having an inwardly opening axial `relief bore 55 which is open to atmosphere through ports-51 near the outer end thereof.4 When the handle 46 is depressed the inner end of the plunger bears in sealing rengagement against the head of the valve member 48 and closes the bore 55. A light compression spring 58 within the relief bore 55 seats upon the forward-face of the valve member 48 and acts to separate the handle 44 is released, thus opening the bore 55 and effecting a passage to atmosphere via the bore and the ports 51,.

After the pressure iiuid leaves the control valve mechanism 40 by way of the outlet port 54, it is delivered to the cycle governor- 4l through .a nipple Sllupon a casing 6I within vwhich the governor mechanism is contained at the rear of the barrel l0. The governor oper# ates to direct the pressure fluid to actuate the pistons 22' and 23 in proper continuous sequence forward and back, that is in successive power and return strokes, and at the end of the return stroke positively halts further operation of the tool until reconditioned, as will be more fulll7 described hereinafter. Thus, the tool will operate only through a single cycle each rtime the control valve handle dil is depressed and will not accidentally repeat, a repetition of the operating cycle requiring release. and reactuation of said handle.

From the nipple G the pressure uid passes through an inlet port into a barrel 53 which is fixedly secured within a bore 5d `in the goverl .threaded into the opposite ends of the here. Within the barrel is 'a longitudinally reciprocable governor plunger or piston valve body whichhas a peripheral groove e@ registering with the inlet port Si and with a discharge port inner end of the plunger 45 therefrom when thev nor casing ti by means or" closure disks 55 and 1n te dlreetthe pressure mixato a delivery duct 1| communicating with the back ofthe rear piston chamber 25. 'Ihere the pressure fluid be.

.comes effective to drive the rear piston 23 forwardly and in part passes through an axial passage 12 and distributor ports 13 in -the piston rod 21 tothe back of the front piston chamber 24 for driving the-piston 22.

During the driving or power Vstroke of the pistons air in front of the piston 22 is exhausted to atmosphere through suitable openings (not shown) At the same time air in front of the rear piston chamber 23 is exhausted through a 4port 14 at the forward end ofthe piston chamber 25 and travels through a passage 15 formed inthe side and rear walls of the barrel I8 and communicating through a port 11 in the valve barrel 63. The exhausting air escapes to atmos phere from one side of the valve barrel-through an exhaustport 18 which is maintained in communication with the port 11 by a peripheral groove 19 in the valve body 63.

lThroughout the power stroke of the pistons, the valve body 68 is held by suitable resilient means such as a compression spring 88 in what may be termed a normal or initial position (Fig. 1). For'this purpose the spring 88 seats at one end against the closure disk 65 and projects into an axial bore 8| provided therefor in the adjacent end of the valve body 88, the force of the spring normally holding the opposite end of the valve body `in abutment with the closure disk 61.

When the pistons have substantially reached vthe forwardend of the power stroke, the rear piston 21 .uncovers a port 8 2 located at a predetermined intermediate point of the side wall of the rear piston chamber 25. Live pressure fluid immediately passes through such port and into a passage 83 which communicates by way of eport 84 in the wall of the valve barrel 63 and a peripheral groove 85 and ports 81 -with a chamber or pocket 88 formed as a short axial bore in the end of the valve body 68 which opposes the closure disk 61. Upon reaching the pocket 88, the live pressure fluid is trapped and develops sufllcient force to compressthe spring 88'and push the valve body 68 away from the closure disk` 61 and into endwise Aabutment; with the closure diskV 85.- As a result, the peripheral groove 19 iscarried out of register with the exhaustv port 18 and registers with the vpressure iluid inlet port 62 while the groove 69 is carried out of register forward end of thevrear piston chamber 25 to return the piston to starting position.

At the end of the return stroke,'the pistons are halted by continuously maintaining the iluid pressure trapped in the pocket 88 and between the adjacent end of the valve body 68 and the closure disk 61 until the source of pressure fluid supply is shut oif by the control valve 48. To this end a small pressure fluid duct 98 communicates between the pocket 88 and the grove 19 in the valve body, and the port 84 is arranged to be closed as soon Vas the groove 19 registers with the live pres,- sure fluid port 62,-V Thus, the pressure pocket will remain active as long as live pressure fluid is admitted into the governor from the beginning of` driving piston I I I.

To repeat the operating cycle it is then neces'- valve 48, and open the relief valve 45 which will vent any pressure uid remaining ahead of the control valve, including that within the pressure pocket 88. Instantaneously thereafter, the spring 88 pushes the valve body 68 back to the initial position, thus reconditioning the cycle governor for a repetition of the cycle of operation.

Should therivet sets I3 and I1 be too closely adjusted or an obstruction Vencountered to halt the power stroke of the pistons before the intermediate port 82 is uncovered by the forward piston 23, the tool will stall. Means is therefore provided for manually shifting the -valve body 68 in opposition to the compression spring 88 to effect return' of the pistons and release of the rivet sets. Herein a release pin 9| is mounted slidably in the closure disk 61 and projects into the pocket 88 to be pushed inwardly for shifting the valve body 68. Intermediate its ends the pin has a retaining collar 92 which serve during normal operation as a pressure uid seal to avoid leakage around the shank of the pin through the closure disk 61.

'I he modified form of the invention shown in Fig. 6 has lbeen devised with the particular view of entering limited working spaces where riveting tools of this type have not been permissible heretofore. For example, in riveting together a pair .iecting nose 99 providing a fixed rivet set. Co-

active with the flxedset is a movable rivet set |88A formed as a head upon a hammer-like ram or jaw |8v| which has a rearwardly projecting arm |82 pivotally connected by a pin |83 within a longitudinal slot |84 formed in the attached leg of the yoke. Opposite the rivet set |88 the hamf mer ram- I8| has a heel |85 which is movable between a pairof parallel guides |86 (only one of which is shown). by a pivot pin |81 to the forward end of a driving link |88. The opposite en"d of the link |88 extends into the barrel 98 and is pivotally connected by a pin`| 89 in the bifurcated forward end of a piston rod I|8 which projects forwardly fromv a As shown, the driving link I 88 is formed in two parts threadedly connected for longitudinal adjustment to adjust the spacing of the rivet sets. It will be observed that the rivet sets are so located and placed on such an axis relative to the axis of the barrel that the sets may approach close to the faces of the plates 93 without interference from any other projecting Darts of the tool.

Pressure fluid for actuating the piston I I I is dedifference is that instead of moving in a straight line perpendicular to the `axis of the piston rod ||8, the forward pivot |81 of the ram will travel in a slight forward arc on the radius of the ram pivot pin |83. Distortion oi* the piston rod |88 by The heel is pivotally connected side thrust is avoided by a thrust plate iii which engages the thrust side of the piston rod and which at the peak of the thrust is engaged by anti-friction rollers im.

Use of merely the control valve assembly da will suice for controlling and governing operation of this tool, the piston placing a spring @E under compression 'during the power stroke and the tool stalling at the end of such stroke. Then when the valve control handle te is released, the compressed spring H5 will force the piston back and the spent pressure fluid will exhaust through the relief valve d5.

From the foregoing it will be apparent that the invention provides a riveting tool construction which embodies simplifications and improvements rendering the tool more compact and lighter in -weight;` more positively controllable; and more ecient in operation due to factors such as reduction in power losses from friction, freedom from distorting thrust strains upon moving parts, and more gradual development` of riveting colmpression. Furthermore, such a tool is provided which is capable of riveting under conditions of limited working clearance for which prior tools of this type have not been available.

I claim as'my invention:

1. A tool of the character described comprising,'in combination, means carrying a stationary tool member, a ram having a tool member mounted for movement in a fixed path toward the stationary tool member, driving means `for said ram including a pressure iluid actuated piston having a'forwardlyprojecting pistonhrodA movable rectilinearlylat an angle to said path of movement of said ram, and a single connecting link between said piston rod and said ram, said link comprising two parts threaded together for relative longitudinal extension or contraction in adjusting the length of the link and controlling the spacing of said tool members,

2. In combination in a power tool of the character described, a stationary tool member and a support therefor comprising a relatively massive body having a slot in its base portion, a substantially hammer-shaped movable tool membery including an elongated arm having means at its front portion cooperative with said stationary tool member for placing a work piece under compression between the members, said arm extending rearwardly within said base slot and having its'rear end pivotally secured therein, a heel on the forward end vportion of the arm opposite said compression means., reciprocable power means guided for movement on an axis extending in generally the 'same direction as said arm, and a single link pivotally connectedito said heel and to said power means for swinging said arm hammer-like to carry said compression means toward and away from said stationary tool member 'in .the reciprocations ofsaid pOWeI 11168.115.

Zi. A portable riveting tool comprising, in comacreage spaced rearwardiyirom the forward end oi the rod and engageabie with said bearing surface after an initial advancing movement of the piston.

d. A portable riveting tool comprising, in combination, a cylinder having a piston therein and a piston rod extending forwardly from the y piston, a bracket mounted on said cylinder and adapted to support a stationary tool, said cylinder having coaxial therewith a forward extension of reduced diameter, said forward extension and said bracket providing a guideway extending in a direction perpendicular to the axis of the cylinder, amm-mounted for sliding movement in said guideway, a link connecting the forward end of the piston with the lower end of said ram, the forward end of said link being enclosed by said extension, and a bearing plate secured in the lower portion of said cylindrical extension for guiding and supporting the forward end of the piston. y

5.y A portable riveting tool comprising, in combination, a cylinder having a piston therein and a piston rod extending forwardly from the piston. a bracket mounted on said cylinder and adapted to support a stationary tool, a movable tool carrier mounted for movement in a path extending in a direction transversely of the axis of the cylinder, a link pivotally connecting the forward end of the piston with the lower end of said carrier, the pivotal connection between the link and the piston'including a head'on the piston and a pivot pin on the head, a. roller carried by sald'pin, and means providing a bearing surface spaced forwardly from said roller in the retracted position of the piston, said head slidably engagingv with said bearing surface in the'initial portion of the advancing stroke of the piston.

6. A portable riveting tool comprising, inco'xn- I bination, a cylinder having a piston therein, and having coaxial therewith a cylindrical extension of reduced diameter; a' bracketmounted on one side of the cylinder and adapted to support a stationary tool in laterally spaced relation relative to the cylinder, a plate closing the forward end of said cylindrical extension and cooperating therewith and with said bracket to provide a guideway extending transversely of the axis of the cylinder, a ram slidable in said guideway and adapted to carry a movable tool, and a link: connecting the forward end of said piston with the lower end of said ram.

7. A portable riveting tool comprising, in comy bination, a cylinder having a piston therein, and

having coaxial therewith a cylindrical extension of reduced diameter, a bracket mounted on one side of the cylinder and adapted to support a stationary tool in laterally spaced relation relative to the'cylinder, a plate closing the forward end of said cylindrical extension and cooperating therewith and with said bi acket toprovide a guideway extending transversely of the axis of the cylinder, a ram siidable in said guideway and adapted to carry a movable tool, and e link connecting the forward end of said piston with the lower end of said ram, said extension having a bearing plate slidably engaged by the forward end of the piston in the retracted position of the latter, and a roller on the rear end of said link engageable with said bearing plate in the forward movement of the piston,

hanger n. snare.

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