US2718798A - Stroke adjuster for riveting machine - Google Patents

Description

Sept. 27, 1955 H. R. FISCHER ET AL STROKE ADJUSTER FOR RIVEITING MACHINE 1 R QQ R 5 a m M m N m f V .w w uw m e H MA m w M S am Original Filed Dec.

Sept. 1955 H. R. FISCHER ET AL 2,718,798

STROKE ADJUSTER FOR RIVETING MACHINE Original Filed Dec. 13, 1943 2 Sheets-Sheet 2 IN VEN TOR.

2V HOWARD R. F/SCHER Q JAMES A. ROBER rs /$77'70RNE Y United States Patent 2,718,798 STROKE ADJUSTER FOR RIVETING MACHINE Howard R. Fischer and James A. Roberts, Detroit, Mich, assignors to Chicago Pneumatic Tool Company, New York, N. Y., a corporation of New Jersey Original application December 13, 1943, Serial No. 514,068. Divided and this application July 8,1950, SerialNo.172,668

3 Claims. (CI. 9848) This invention relates to fluid actuated machines for setting rivets, dimpling sheet metal and more particularly to a stroke adjuster for regulating the return stroke of a fluid-operated plunger;

This application is a division of our application, Serial No. 514,068, filed December 13, 1943 (now abandoned), and relating to compression riveters.

It is an object of this invention to provide with a compression riveter a return stroke adjuster arranged to prevent the plunger from being moved more than a predetermined distance away from the rivet and thereby to permit the operator to align the plunger more accurately with the work.

It is another object of the present invention to provide a return stroke adjuster for compression riveters wherein there is provided means for easily regulating the length of the return stroke of the plunger, means for moving the adjuster at will to a non-obstructing position, means for holding it in the non-obstructing position during the succeeding power stroke and means for automatically returning or restoring the stroke adjuster to its previously selected position of adjustment upon the termination of the succeeding power stroke.

For other objects and for a better understanding of the invention, reference may be had to the following detailed description taken in connection with the accompanying drawing, in which:

Fig. l is a fragmentary side elevational view of a press for riveting or dimpling operations constructed according to the present invention, but with the lower or base por tion thereof being broken away.

Fig. 2 is afragmentary view of the upper operating mechanism shown in Fig. 1 with certain of the parts in section to disclose the interior construction thereof.

Fig. 3 is an elevational view taken from the rear of the segmental guide for the return stroke adjusting lever.

Fig. 4 is an elevational view of the segmental ratchet for the return stroke adjusting lever.

Fig.5 is: a side elevational view of the ratchet shown in Fig. 4.

Fig. 6 is a cross-sectional view taken on line 66 of Fig. 2 through the upper frame of the machine and looking rearwardly and showing the return stroke adjuster in its normal or operative condition.

Fig. 7 is a cross-sectional view similar to Fig. 6 with the stroke adjuster shown in its disabled or non-operative position. i

Fig. 8 is a side elevational view of a stroke indicator, used inassociation with the present invention.

Fig. 9 is a fragmentary plan view of the stroke indicator.

Fig. 10 is a rear elevational view of the stroke indicator.

Referring now to the figures, a riveting machine, 'generally indicated at 30, consists mainly of a yoke 31l1aving upper and lower opposed jaws 32 and 33 and supported rigidly upon a column 34 that extends from a base, not shown. The jaws .have considerable length and the yoke is made of material having great strength, toughness and elasticity, such as boiler plate steel in order to permit the development of a riveting pressure of many tons, with a consequent spreading apart of the jaws 32 and 33, but without straining the. yoke beyond the elastic, limit or developing fatigue of the metal thereof.

In the lower jaw 33, there is mounted a stationary rivet 2,718,798 Patented Sept. 27, 1955 supporting tool, dolly, or anvil 36 which is normally fixed to the yoke, but which may be adjusted relative thereto.

The upper jaw 32 has a complementary movable riveting tool or set 37 carried by plunger 38 and capable of being brought down during the operation toward the stationary rivet-supporting tool or anvil 36. The plunger 38 is slidably mounted for vertical movement in vertically spaced bushings within the jaw 32, the upper one of which being shown at 39, and the lower one of which being in the bottom of the jaw 32 at 41. These bushings are fixed in a bore 42 and the plunger extends below the lower bush- 'icc ing 41 and has in its lower end a tool socket 43. A tool anchoring rod 44 runs through the plunger 38 to establish a detachable threaded connection with the tool 37 to retain the tool in the tool socket 43. The rod 44 has a shoulder 44 which abuts against a corresponding seat in the plunger 38 to hold the rod against downward displacement throughthe plunger 38 and the tool within the socket.

The upper end of the rod 44 is hollow and is provided with a slot 45 in which is fitted key 46. One end of the key 46 extends into a keyway 47 of the bushing 39. The key 46 thereby serves a double purpose in holding the rod 44 against rotation relative to plunger 38 and the plunger 38 against rotation relative to the bushing 39 when the rivet set 37 is screwed, on the lower end of the rod 44. The bushing 39 is locked against rotation by a set screw indicated at 48. The necessity for turning this bushing 39 at different angles-arises when an offset rivet is being used so that the tool set may be turned in different directions to suit the work. A spring pressed detent element 49 is adjustable in the hollow upper end of rod 44 and presses against the key 46. The rod 44 is thus urged downwardly relative to the plunger 38, but is permitted to rise against spring pressure of spring 49 in the event that an upward force is applied .to the rod 44. The purpose of seating the rod in a resilient manner is to prevent injury to the threaded connection between the rod 44 and the tool set 37. In the event that this connection may work loose; and the shoulder of the rivet set 37 drops away from plunger 38, no damage will result, for the reason that each time the machine is operated, the shoulder of the set strikes thelower extremity of the plunger 38 whilethe rod 44 is free, to slide up and down on the key 46 and prevents injury to the threaded connection which might have resulted if the set 37 was screweddirectly to a rigid part of the plunger 38. A collar 51 is fixed about the plunger 38 and engages with a return compression spring 52,.and rests upon the lower bushing 41, this spring tending to raise the plunger toward its upper inactive position.

At its front end, the yoke jaw 32 extends upwardly and has transverse bolts 53 to connect upper frame 54 thereto. This upper frame 54 being generally of U-shape in section, as seen in Figs. 6 and 7. The front end of the frame 54 is closed by a plate 55. The rear end of the frame 54 is bolted to a fluid drive cylinder 56, which contains a chamber 57, and to which in turn ls-bolted acontrol valve housing 58. Within the U- shaped frame 54 is an operating cam lever 59 pivoted to.

the frame 54 upon a pivot 61 and provided with a nose 62 making pressure contact with the upper end of the tool plunger 38 and during operation serving to depress the upper edge 59' of cam lever 5:9'while the upper roller 69' rolls along a rail71 secured to the top of the frame 54. As shown in Figs. 2 and 7, the rollers 69 and 69' roll over each other thereby relieving the forked block 68 of a large part of the reaction which is transmitted from the carn lever 59-and upwardly through the rollers to the track rail 7 l-and yoke frame 54. .1 Aninner piston rod 72 is screwed at its forward-{cud intothe shank portion 61oftheforkedwollenblock '68 r" and passes through hollow piston= 64;-- onthe-rear side'"" of WhichLit has an-incre-ased diameterportion72"sur rounded bya 'sleeve 73 retained-in association therewith by a-Ibolt 1'74- screwed on the rear-end of said -rod"72'.'i10 Thus,. if 'the=piston:63 is-in arearward position,"the roller block 68- willalso occupy a rearward retracted position in which thelower: roller 69-'- engagesiin a depression 75 i in the...-upper.*edge of-the cam-=lever and-nearfpivot 61 thereof-which.allows-thespring-52 through the collar- 51 to. raise; the :plunger 38and thereby swing the cam levert59, upward to a raised inclined position about its pivot 61-;..-. c... e 1 Whem-the rollereblock 63;is forcedforward, by theforward travel of.-the =piston- 63, the latter being driven by fluid under pressure entering chamber 57, the upper roller,,69.-engaging: the rail 71 and the lower roller 69 engaging th'ecanr lever.59 .will-obviously swing the cam lever .,down ,progressively and thereby cause -thetool plunger. 38 to descend with; the set 37 toward the riveting 5 tool or dolly .36 in the lower jaw 33 of the yoke 31-. The upper, edge 59 of the cam lever'59 is preferably straight, a as is,shown, so. that the leverz59 and" the plunger 38 are movedfirst rapidly sdueto the: fast outer travelof the nose;62. whenvthe roller. 69? setson the lever at points near the pivot;.61 and then more slowly, -but with a-uniformgmechanical advantage or speed ratio between the--- piston .,63 1.and therplunger 38 as the roller 69' reaches the nose end 62 of the lever 59. ..'l?heresult is that the pressurepntherivet is. uniform throughoutthe power 5 stroke so longas the ,air pressure behind the piston 63 is constant; ,Within limits therefor, variationsin the thicknessgf the metal sheets being operated-on, with cor-e responding variations in the lengthof the-power stroke, will not: alter the shapebfthe headed rivet or tensity ;of the forcesuppliedthereto. a In order to actuate the piston 63 and thereby the cam' lever 59,and plunger 38, fluid is. passedato'the chamber 57 from gtheyalye housingSS. .;Exhaust air flowingfrom the frontof the piston chamber 57'passes.through speed-' control. valve 13 1, Fig. 2,: which regulates the piston velocity. on the-power stroke. ;-.From .the .valve,-it flow's 5 the in- 40 throught a rnuflier l-29 to the atmosphere.- ..Valve. 1'31is of the .s c rew type and provides an adjustable restriction -11 for the.;escaping air, -I t is operatedbyi a=manipulative wheel- 132. This wheel132 is supported. on the cylin-p 9O der 56jwhilethe valveseat lieslinnthe, cylinder head 77., The purpose of this speed control valve is to be able -to= 1 regulate the velocityof travelof the,piston,63:during thepower'st roke' 'Iurningjhe wheel: 132 :-counterclockwise increase'slthelspeed of the piston while turning the wheel clockwisegdecrea ses the speed ,by; further; restricting: the flow Ofexhaust from the front cylinder chamber to suit riveting conditions. =A l'l'1agntiC;,CDilidCViCfi'ROI' sole-" noid 134 serves to, operate the control.; valve.58.= iFluid under pressure is supplied tothe control-valve 58 through r60 a hosefilwhich leadstoa suitable footcontrolled device, -a: not shown, and-which is in turn connected to a fluid pressure source :11; 2/1 .1 em ezi ql PPd to. enable the operatorto ascertain the extent of the stroke of the piston in the' forward ,operating direction, This featurexuincludes "a I general visual index to the finished; size. ofi-Etherivefibeing set and,- the thickness of the material constituting the work piece}; p 1, 1 I :-L Ix Referring now-particularly 10 Figs. 2, 8 9;-anda.10, the..= stroke indicator comprises a tubular-guide. 1 51 arranged in the lower portion o f the frame 5.4,and parallel with the ree in i Q tr ve pf the piston... ;.An..indicator;rqd 153 has l-lowerihorizontal pgrtion 152 slidably. guided? in said tubular guide member 151. The rear end of the frame-j54. It'has a verticalflange provided 'with'a hole tent thereafter;

knurled adjusting knob 168. 'A locking knob 177- -Will 37 andfthe dolly.or 'anvilt36 is-considerably greater when A separated-;. byi' their 1 maximum distance length of a rivet or the thickness ofthe' 61 so that the rivetset: 37 wi-ll. have but a smalldistanee to travel toward-the work piece which amounts to me're 7 extension 51-81 near the fulcrum? end=-of lever' '59 which. .5 may be -engaged by an-oseillating cam -182. This vosci l v .=.lating cam 182 consists-of'a-co1lar182.having an ec-x rod is provided with a knob or finger piece 154 accessible from beneath the cylinder'56 for manually withdrawing the indicator rod when the piston isin its rearwardposition. The indicator rod 153 is provided witha' Tve'r tical portion which will be pushed forward'byifciller- '1' block 68 until'the piston ceases to move saidblock,'with the result that the indicator rod and its finger piece .154 come to rest' in the attained extreme forward position of the'rod. The vertical portion 155 of the rod is held in a vertical position by engagement withthe sides of the U-shaped or channeliportion"'156 of the guide member 151 which 5 lies intermediaten'to cylindrical portion's 15-7 and 158'."- Thus, the'vertical portion Ior arm=155-=rnay' be-car'ried I throughout the length of channel portion 1-56. i uitabl'e indicia, not: shown, may 'be provided on the horizo'nta'l arm 152 'of. the indicator rod 153' to 'indicatethe distance that the arm projects beyondithe' rear end of the :e l-in dricalwportion 158 of :the 'guide memberJSL A -brackt 159 supports the =tubular' guide membe'r 151 "-onthe" 162 to receive a capscrew 162 Figs. 6 and-7, =by means 13 of which' the bracket is attached to the inner wall of the U-shaped frame 54. .1 :w 21.: Ifit'tilollg :r vet? and a 'heavy "work piece should-be handled by the machine, the knob 154-will obviously not be brought as-far-forwardms lwhen smaller rivts-" and l-ighterwork pieces are operated upon The forward limitiposition may be noted by the operatorin' conjunetion Wilihgthe test rivet. The te'sting proeeeds' until tlie setting-of the. ;.test .rivet'is 'virtually perfectt The m'a chine is thenzadjnsted to operate to exactly the same ex As stated above, the upper edge: 59 of thecam -leve 59 hasaanportion of limited lengthwhich-is so shap'ed that asthe'roller 69'passes'thereover, there -is-a-unifor rri mechanicalvadvantage orrs'peedratio between piston-"'6' and plunger 38. Uniformity of pressure for the "rivets is obtained byterminating each 'power'strokewit-hin the" limitsof-thisconstant pressure'range." "If the'stroke' in- Y dicatorqshows that-thepower stroke is too short or too Y long for this purpose, the operator=may adjust the fo'r wardstroke by lowering or raising' the position of the dolly or anvil 36011 the lower jaw 33 of-the yoke. i1? A micrometer arrangementtisprovided forthe' adjustment of the dolly-6.6 which includes a screw 163 and a fix theiscrew r163einaplace after the'adjUstmnt-thrb has been effected. A detail -description of thismicrorrie ter arrangement will: be found in the above-mentioned parent application.

It is understood that the full gap between the rivet set par-t, tha'ri the material of; work ,piece, s0 that there will be -los't niotion at 'eac stroke -by the.-rivet set beforee it' m'ake's cdntact-ivith therivet to be set, unless some expedient is resorted to for eliminatinglsuch lost motion; This may-be avoided by limiting the return strokeof'the plunger 38' through lirni- 1 tationzof the -.raising or return"movement 'ofthe cam lever 59 to its normal raised idle position about its pivot clearance; for. placing; saidrv-worki piece and -rivt -npon the machine, The object inlimitingQthe return -stroke of the plunger 38 is .to aid the operator in aligning the work with the rivet set 37 by stopping the rivet set near 1": .f l r11. .2

The. return stroke: adjuster: of the present 'inven'tion is best illustrated in Figs-..:2,"6=and7-.- '-It compi'i'ses"a hoo centric flange and is rigidly mounted upon a horizontal shaft 183 which is supported for longitudinal and rotative movement in the spaced walls of the frame 54. One end of the shaft 183 projects beyond outer side of the frame 54 and terminates in a forked extension 184. This forked extension carries a transverse pin 185 which provides a pivotal support for the upper end of a stroke adjusting lever 186. This lever 186 has a depending and outwardly bent handle portion 186. The lever 186 is supported, as a pendulum, for universal movement, being adapted to swing relative to the shaft 183 about the axis of pin 185 and also being adapted to swing in unison with the shaft 183 about its axis. The range of movement of the lever 186 is limited by a ratchet teethed segment 187, Figs. 4, 6 and 7, and a segmental guide 188, the segmental members being arranged in spaced relation and secured by screws 189 to a depending portion of the frame 54. The lever 186 has a knife edge where it engages the teeth 187' of ratchet segment 187 and is yieldingly held in engagement therewith by a spring 191 riveted to a holder 192 which 'is suspended on lever 186 by a pivot pin 193.

The range of travel of the return stroke adjusting lever 186 is throughout the arcuate length of the segments or quadrants 187 and 188. Fig. 2 illustrates two positions of adjustment, the medium stroke position being in full lines and the short stroke position being in broken lines.

The space provided between the front and rear quadrants 187 and 188 is sufficient to allow lever 186 to travel forward and backward without engaging the ratchet teeth 187 when a light pressure is exerted on the lever against the guide member 188 upon movement of the lever to a new position of adjustment. A spring 194, surrounding the shaft 183, tends to hold the shaft in the position shown in Fig. 6. With the parts in this position, the return stroke of the piston 63, in response to air pressure, is accompanied by a partial return of the plunger 38 under the influence of spring 52. Upward movement of the plunger 38 is arrested when the hook extension 181 of the cam lever 58 strikes the eccentric flange on cam 182, Fig. 2, and the teeth 187' of the ratchet segment 187 prevent the lever 186 and the cam 182 from swinging and thus holds the parts in place.

To remove the cam 182 from the path of the lever hook 181, the operator grasps the handle portion of the lever 186, presses it toward the side of the yoke 31, Fig. 7, pivots the lever over the ratchet segment 187, thereby pulling the shaft 183 and cam 182 to the position shown in Fig. 7 against the pressure of spring 194. This lateral movement of the cam 182 releases the cam lever 59 and the plunger 38 for upward movement in response to the spring 52. Should the operator then release the pressure against lever 186, the parts will remain in the position shown in Fig. 7 until the subsequent power stroke of the machine when the hook moves out of the path of the oscillating cam 182 and permits lateral movement thereof under the pressure of spring 194. Thereafter, the stroke adjuster is again effective to limit the travel of the cam 59 and the plunger 38 on their return stroke.

When a rivet is actually in the process of being set, the yoke is expanded to a degree corresponding to the pressure applied to the rivet, due to the forward pressure of rollers 69 and 69 between the track 71 and the cam lever 59. The pressure applied to the riveting plunger 38 is a function of the air pressure in cylinder chamber 57 in back of piston 63, the mechanical advantage between the 'plunger and the piston being substantially constant during the heading operation. As the air pressure, and hence the pressure of the rivet set upon the rivet, gradually but quickly builds up, the jaws of the yoke spring apart in a direct ratio to this pressure exerted on the rivet.

It should now be apparent that there has been provided with a riveting or dimpling machine, utilizing fluid pressure for its operation, a simple indicating means to indicate the length of forward stroke of the piston and means whereby the return stroke of the plunger 38 can be adjusted, the cam lever 59 being stopped by the adjustable cam 182 upon its projection 181 engaging with the earn 182.

The stroke indicator shown in- Figs. 8, 9 and 10 is claimed in a copending application Serial No. 264,219, filed December 29, 1951, which is a division of the present case. The assembly of the plunger 38, rod 44, rivet set 37, key 46 and spring-pressed detent 49 is claimed in another divisional application, Serial No. 264,220, filed December 29, 1951, which has issued as Patent 2,682,793 dated July 6, 1954.

While the various changes may be made in the detail construction, it shall be understood that such changes shall be within the spirit and scope of the present invention as defined by the appended claims.

What is claimed is:

1. In a press for performing riveting and similar operations, a frame, a working plunger reciprocable therein, power means for moving the plunger downwardly on its power stroke including a pivotable member on said frame engaging the upper end of the plunger, means urging the plunger upwardly following the termination of the power stroke, a return stroke adjuster mechanism for shortening the return stroke of the plunger, said stroke adjuster mechanism including an adjustable stop means obstructing upward movement of the pivotal member, a manipulative device for adjusting the position of the stop means relative to the pivotal member whereby to regulate the length of the return stroke, said manipulative device being adapted to move the stop means at will out of its obstructing position to permit the full return stroke.

2. In a press for performing riveting and similar operations, a frame, a plunger adjustable in the frame, a pivotable member mounted upon said frame and engaging said plunger, power means operable upon said pivotal member to depress said plunger, means urging the upward movement of the plunger following its power stroke, said pivotable member having a depending hook extension, a return stroke adjuster mechanism including an adjustable stop element adapted to be engaged by the hook extension of the pivotable member, a manipulative handle device for adjusting the stop element in a plurality of adjusted positions and ratchet teeth means on the frame for retaining the manipulative handle device and the adjustable stop element in their adjusted positions.

3. In a press for performing riveting and similar operations comprising a frame, a working plunger reciprocating therein, power means for moving the plunger downwardly on its power stroke, means urging the plunger upwardly following the termination of the power stroke, a stroke adjuster for shortening the upward stroke of the plunger to more than one position of adjustment, said stroke adjuster including a cam obstructing upward movement of the plunger, said cam being rotatable to vary its effectiveness and the length of the return stroke of the plunger, manipulative means including a lever positionally operable for moving the cam laterally away from any selected position of adjustment and into a nonobstructing position, and means for automatically restoring the cam from its non-obstructing position to its previously selected position of adjustment upon release of the manipulative means.

References Cited in the file of this patent UNITED STATES PATENTS

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