US2658966A - Compression riveter switch - Google Patents

Description

Nov. 10, 1953 H. R. FISCHER ETAL 2,658,966

COMPRESSION RIVETEIR SWITCH Original Filed Dec. 13, 1943 2 Sheets-Sheet l w 1 j MW 13 ,9 W Li i o I N V EN TOR. HOW/QED 1?. FUCHER J/YMES 19. R055)? 745 H. R. FISCHER ET AL COMPRESSION RIVETER SWITCH 2 Sheets-Sheet 2 Original Filed Dec.

INVENTORJ' F'IJ'GHEI? Horny/w 1?.

Y M m a r d M/ 5 MW J Patented Nov. 10, 1953 CQMPRESSIQN RIVETER. SWITCH Howard B. Fischer and James A. Roberts, Utica,

N, Y. assignors to Chicago Pneumatie'Tool Company, New" York, N; Y.; a corporat on of Original application December 13, 1943., Serial 8 Cl aims. 1

This invention relates to electric switches, and particularly to a switch for 'use asa deflection trip'switch with machines in which the deflection 'of a part of the machine, during operation, is utilized to operate th e switch to control an external circuit, and is a division of our application, Serial No. 51 4,068,' filed December 16,1943 (now abandoned) ,relating to compressing riveting machines.

"One object of -this invention is to provide a sensitive control switch suitable for use with a massiveri veting machine of the open jaw type, in which a relative deflection of one jaw .with respect to the other jaw during operation, is utilized ,to operate the switch when the deflection reaches a predetermined value for which the Switch m y be accuratel ad te Another je t 91th? in n on is, to i e a control switch of theioregoing type inwhich a sensitive switohoi the microrswitch type is employed and in'which the operating member of the switch is disposed to be, controlledby a deflection measuring member h the machine, to operate the switch when the deflection member indicates a relative displacement of the jaws of the machine amounting to a predetermined distance for which'the switc'h is, or has been adjusted.

Another object of the invention is 'toflprovide a switch of the foregoing character; in which all parts of the switchare formed of relatively rugged members; and yet the construction of the switch is such as to permit of very sensitive .ope erationand a micrometer adjustment for adjust/- ably setting the switch tooperate at apredetermined deflectionof a jaw of the machine.

The construction of the switch in' accordance with the present invention andits mode of application and operation'jare illustrated in the accompanying drawings,.in whichz' Fig. l is a side elevational View of amassive ma h n of the open iawiriv'etin tyne, employin a deflection plate to obtain a measureof the relative deflection of one jaw 'of the machine "when underpressure duringoperation;

Fig. 2 is a front elelvational'v'iew of the switch, with a portion of ,the'deflection plate shown in normal operating positionrelative to'th'e'switchi Fig. 3 is a sectional view taken along the line 3-3 of Fig. 2 to illustrate the disposition of a fulcrum ferrule for the operating arm of the switch;

Fig. 4 is a sectional view taken along the line 44 of Fig; 2, 110 illustrate'the' guide restraint for the free end of the deflection pIateinits movement to operate the one end ofthe actuating arm of the switch; and 7 Divided and this application lviay T on Fig. 5 1s an elevational front view of the adjustable'switch plate that carries the microswitch: V.

As generally illustrated in Fig. l, a fluid actuated riveting machine Ill consists of a massive yoke structure H and terminating at thefront of the machine in two opposed vertically spaced jaws l2 and [3 for respectively supporting two cooperating rivet-shaping tools and [5; 'The yoke"! I is supported rigidly on a column Is that in turn is supported and affixed to a substantial stable piece ll. The two jaws I2 and I3 extend forward from the main body of the yoke. The yoke structure is made of inaterialhaving great strength; toughness and elasticity. such as boiler plate'steeLin' order to permit the development of a riveting pressure of many tons. Consequently, the jaws l2 and I3 may be spread apart slightly, during suchpressure operation, without straining the yoke beyond'the elastic limit'or development of fatigue of the middle. For the purpose'of the present application, it is sufficient to note briefly that the tool 15 in the lower jaw is adjustably positioned and fixed in the lower jaw l3 to provide one adjustment in the spacing between the jaws of the machine to provide for shaping of rivets of different lengths. The upper tool [4 in the'upper jaw I2 is carried by a plunger that need not be shown for the purpose of the present invention but that is controlled by pressure generating device [8 supported at the upper end of the top jaw [2. During operation the plunger is brought down to force the tool 14 towards the bottom' tool or dolly IS in order'to compress any rivet that may be disposed between the two tools l4 and 15.

The operating fluid for the pressure device I8 is supplied from a suitable sourceof pressure supply through a'conduit 2t at the bottom of column it and thence throughsuitable air line oiler .23 and a pressure regulator 24. controlled by its. regulatingohandle Y25 .and thence pasta pressuresaugec tlthroughia conduit, 21, to the c lind o t ep essu e en rat n unit H3.

Th .l psrtt im rt e machin is arranged to be wi Qllfldb a QQt sw 3 ro ided.v with mor mtm mean, h r t on of th n t switch f '3- l completes. a circuit to the electrical control apparatus Whit"? I initiates operation of the equipment including the pressure generating c r 1% m vei sf l l eer downw d arid forcethe tool I4 down towards the dolly or anvil 15;} in order to operate on 'a rivet disposed between those twotools I iand l5. Vii-hen the'two tools l4 and 15 engage a rivet and impress a compression force on the rivet,

the reaction pressure against the two jaws I2 and I3 tends to separate them slightly. That separating movement is measured, and is utilized to control the operation of the machine in a normal sequence of operations. The nature of the control operations in that sequence is not necessary to an understanding of the present invention, and the present reference thereto is made merely to indicate that the separation of the jaws is measured to control the operation of the switch of the present invention.

In order to measure the separation for deflection of the two jaws l2 and [3, during operation, a deflection plate 36, of substantially U-shape, is mounted on and supported by the main yoke H of the machine, in such manner as to be slightly spaced on the main yoke l I and free of any reaction force from the two separating jaws l2 and 13. The lower arm 31 of the deflection plate 36 is secured at its end to the jaw [3 by screws 38 through suitable blocks, not shown, that will serve to space the deflection plate 36 somewhat from the surface of the main yoke H. The back body por tion 39 of the deflection plate 36 is held from bending or swinging away from the main yoke II by a screw 40 which holds that part of the deflection plate at a fixed distance from the ad-- jacent face of the main yoke H The upper arm 4| of the deflection plate extends into the switch box 42 which contains the switch of the present invention. The manner in which the free end of the arm 4! of the deflection plate oper ates the switch is more fully shown in Fig. 2.

The deflection plate remains unaltered and free from stresses and strains arising in the yoke H upon the machine during riveting operation, despite the fact that the jaws l2 and I3 are measurably separated or opened apart when the pressure is applied to a rivet to produce the head upon the same. As the deflection plate thus remains free and unchanged, the movement of the upper jaw l2 of the yoke away from the lower jaw [3 produces relative movement between the upper jaw l2 and the adjacent upper arm of the deflection plate.

It is merely necessary to note at this time that the deflection trip switch is mounted and sup ported as a unit on the upper jaw i2 of the yoke l I. When the upper jaw I2 is deflected upwardly,

during operation, its upward movement relative to the adjacent upper arm 4| of the deflection plate 36 is utilized to operate the switch.

The various movements that are to be measured in this machine are relatively small. A high degree of accuracy is therefore required in the mechanism that responds to those movements in order to actuate the switch. At the same time the switch itself should be susceptible of accurate positioning and adjustment. Notwithstanding these requirements of sensitivity and accuracy, the service to which the switch will be subjected in operation on a machine of the character described, requires that the switch must, above all, be extremely rugged. Moreover, since the machine must be readily adaptable to operation on rivets of various sizes and dimensions, the switch should be quickly adjustable to adapt the machine for operation on rivets of such various dimensions, while, at the same time, retaining its high degree of accuracy throughout the wide range of adjustment necessary for the range of operation of the machine. In order to establish and maintain these desirable characteristics in the switch, it has been designed so that. its

4 cooperating parts will operate with a minimum of friction.

Referring now to Fig. 2, it will be seen that the switch 42 comprises a base plate 43 that supports the switch mechanism, and, in turn, serve as a unit member to be secured to the upper jaw I2 of the yoke by suitable screws through openings in the base plate 43, such as shown at 44 and 45.

For simplicity, the switch contact unit used in this switch assembly consists of a micro-switch 41 provided with the customary operating plungor or pin 48, extending through a protective ferrule into the micro-switch housing. To provide for quick, easy and accurate adjustment of the position of the switch and the end face of its operating pin 48, the micro-switch housing is supported on an adjustable switch plate mounted as a pivoted arm 5 I.

At the side of the base plate 43 is fixed a looking plate 45 which serves as a lateral support for the adjustable switch plate in its movement as a pivoted arm. The locking plate 46 carries a locking screw t9 having a wide inner knob 50 by which the screw may be tightened or loosened manually to lock or to release the pivoted switch plate 51? in position. The locking plate 46 con sists of a rectangular strip slightly spaced from the base plate 43 to provide a space within which a complementary flat portion of the switch plate 5| may move within its plane to engage both the back surface of the locking plate 46 and the front surface or" the base plate 43 with some slight frictional surface contact. The locking screw E9 is threadedly supported on the locking plate 45, and when tightened, serves to lock the adjustable switch plate in position against movement so long as the locking screw is in such tight condition.

The micro-switch is supported at the upper end of the switch plate 59 and its interior contact members are connected by suitable conductors lla to a terminal block Mb, supported at the top of the base 53, to which connections may be suitably made to external circuits that are to be controlled by the micro-switch contacts.

The switch plate 5i is provided with a hole 52 at its lower end to permit the switch plate to be readily fitted over the pivot 53 that is anchored on and supported on the base plate 43. The pivot is anchored to the base plate 13 by a screw 53a and serves both as a retainer and as pivot for the switch plate 5%. The pivot 53 is also formed to have knife-edge 53-19 that serves as pivot to support a deflection switch trip lever 55 in a ii-shaped pivot seat 56 to engage the upper part of the peripheral edge of an opening 5? located at the lower end of the trip lever 55 (Fig. 2). A trip lever 55 has a short actuating arm or force arm 53 at one side of the lower end of the trip lever and relatively close to the pivot mounting, and above the pivot the trip lever has a relatively long upright arm 59 which is spaced but a slight distance from the face of the switch plunger 48. Due to the difference in the lengths of the two lever arms and 59, it is obvious that a slight movement of the short arm will produce a much greater corresponding movement or swing of the long arm of the trip lever 55.

In view of the small movements that occur in the members that are to control the operation of the switch, in this case the relative movement between the upper jaw 12 and the upper arm ii of the deflection plate, it is extremely important that the entire deflection movement r bf said upper men he c, merely a componentjof t a movem tqa'ctuat? e i' w t h m 1 ve .55.. Fo t Pu the lmqvement'of the deflection plate upper arm 4! is'confined to a planar path, without permit t ne any $e c ne s 9 m im. h deflection plate '41 isjprovided with a leveqactur secured to V thefdeflection 31 g .b P t at i j plate arm l by two screws fil Thebl ck 6] is provided witha pivct pin 63 along'its lowerjen'd to support a roller '54 which cooperates With a guide block at t'ohold theactuatingblockfi'l in th Same e r l aneih cu h ut m vem rrhe guide block as is see r ut the base plate 43 by screws G6, and is provided with a seat fi'l forreceiving and guiding. the roller fidjtotspace the actuating block fil ;froin the sides of the slot and facilitate the movement of the block 'n- As the block 61 moves relatively downward against the short arm 58 of the switch trip lever 55, the downward movement of arm 58 is multiplied, by the ratio otthe length of the long arm 59 of lever 55 to the length of the short arm 58, from the fulcrum point of the lever 55 on pivot 53, and that multiplied movement of arm 59 provides anenlargedran'g'e of adjustment for positioning the p front face of the end of the switch plunger 48 relative to the engagin face at the end of the long arm 59' of the trip lever 55. The triplever 55 is kept with its short arm 58 continuously infehgagement with the undersurface of the actuating b1ock lii,. by a biasing spring H having one "end anchoredat screw 12 on the switch base plate 43 and the other end anchored at screw 13 on the arm j59 of trip lever 55. Thus, the trip lever is immediately responsive to even the slightest movement of the deflection plate arm 6! and its' sup'ported actuating block 61 relative to the switchbase plate 153 that is rigidly mounted on theupperyoke jaw I 2. When the relative movement reaches the preset value for which the switch is adjusted, the trip lever 55 moves itsarm 59 to engage and actuate the switch plunger'ds to operate the micro- "switch 41. V v I The operating point of micro-switch 41 is controlled by positioning the switch plate 55 on the pivot 53, The switch plate is biased toward the trip lever arm 59 by a biasing spring 14 having one end "anchored at screw Leon the base frame 43, and the other end attached to the switch plate 55 by a screw '16. That bias spring 74 is effective only While meiocking screw 49 is released to permittheswitch plate to be adjustably positioned. During that time the bias spring serves to bias the plate to the point off'a micrometer adjusting screw "80 to ensure contact of the micrometer against a stop lug 8! on the switch plate, with consequent significance to the micrometer setting.

The micrometer setting to determine the posicen or 'th e-mic ro switc h, when used with a riveting machine "of'th'e kind indicated, depends upor the size of the rivet being set. During that operation, the yoke is expanded to a degree corresponding to the pressure applied to the rivet. Ifhe jaws of the separate in direct ratio to that pressure, but the deflection plate does not share in that eaten-ding movement of the yoke. Instead, when the predetermined pressure is reached, and the jaws are "correspondingly separated, the upper arm 4l of the deflection plate, acting through the actuating block 6| depresses the short arm 58 of the switch trip lever and tact with the switch plunge h ma h es m i' l ith edi f iab f ne a that is accessible to the tperatorrrgm th'e nearer th m chi e t9 @f i pi r fli m w desired of the switch bya'djusting the position of the switchplate 55, v c

c The adjustin means for the switch includes the micro-finite! adjusting screw 8|),itha't is rovided with an operating knob 82 and calibrated; dial 8.3,movable with the screw wand'icoo'pera tive withjthe's'tationary calibrated dial Blto provide an'accurate reading of the adjustedJspacing of the micro-switch from the trip lever. I I

As shown in Fig lth'e operating knob till of the locking screw 49 is accessible Irom the front of the switch cover plate ll2 abeing disposed to project through the switch cover plate, When it is desired to adjust'the switch in order to per:- mit the machine, to operate on a diiferent sizeor type of rivet, th'e'locking screw 49 is loosened by partial unscrewing of that screw by means of the knob 50 in order to release the switch ;plate 5! for movement by its biasing spring hi-toward the micrometer adjusting screw and ad'- justing movement of the micrometer screw against the stop lug 8| offthe switch plate in opposition to the biasingforce-of the biasing spring M. During such adjustment of the'switch plate 5|, the gap :or spacing between the=switch plunger 48 and the facing edge of "the upper end of the upper arm '59 of the trip lever can be varied to increase or decrease the spacing between that plunger an'd'the trip lever. Fora small rivet, the micrometer screw is adjusted to reduce the gap between the trip lever'and the switch plunger. Usually; the adjustment or the machine is tested by setting one or more rivets of the desired sizeuntil the switch adjustment :is correct for the desired "setting of'the rivets.

When that adjustmentis achieved "by the crcmeter screw, the locking screw 49 is' then moved to clamping position by its knob '50 to clamp the switch plate 5! in position against movement by its biasing spring '74, in response to any casual or'undesired external force' When a heavier rivet is to be operated on, the locking screw 49 is again loosened and the'-micrc')meter screw 88 is adjusted to increase the gap between the switch plunger 48 and the adjacent edge of trip lever arm 59, until the machine by testwill set the larger size rivet exactly as desired.

By means of such a switch structure, the setting obtained byadjustment of the micrometer screw 80 will be very accurate. Consequently, once the calibrating screw 80 has been adjusted to the correct position for a giVen size rivet fand definite type of work, an operator'ma'y restore the machine to any such previously ascertained correct setting for thatsame type of work without retesting or lossof time, where the machine has been readjusted for differentrivets and other work pieces requiring different adjustments of the'machin'e in the interim; The calibrated scale 84 may thus be provided with markings to serve as calibrations for that particular switch in relation to that particular machine on which it is mounted for a specific size of rivet and of specific material.

The switch described herein thus serves not only as a circuit controlling device for terminating a rivet setting operation, but will serve also as an accurate calibrating means for quickly calibrating the machine by actual test on a rivet that is to be worked, and thereby provides an accurately calibrated setting which may be utilized for quickly adjusting the machine to a similar position for any work to be done which is a repetition of work that has been previously performed on the same machine.

While various changes may be made in the detail construction, it shall be understood that such changes may be made within the spirit and scope of the invention as set forth in the appended claims:

We claim:

1. A switch for use with the machine of the character having two cooperating jaws and a deflection plate for measuring the separation of the two jaws during operation relative to their normal separation when not in operation, said switch comprising a supporting frame, a microswitch having an operating pin, a trip lever for the switch having a long arm to engage the switch operating pin and having a short arm to be engaged and actuated by a free end of the deflection plate, a fulcrum secured to the frame and serving to support the trip lever for the switch, means confining the free end of the defiection plate to a planar path against the short arm of the trip lever, means for biasing the switch toward the end of the long arm of the lever, a Vernier adjustment screw supported on the frame to adjustably position the switch relative to the operating surface of the long arm of the lever, and means for locking the microswitch in selected adjusted position.

2. A switch, as in claim 1, in which the fulcrum for the trip lever consists of a pivot anchored on the frame and having a definite outer dimension or diameter, and the trip lever is provided with an opening at its pivotal region that is sufiiciently large to permit the lever to be directly slipped over the front end face of the pivot in position, the pivot having an undercut region directly behind the front end surface and of sufficient width to accommodate the thickness of the trip lever and to provide a seat and a shoulder to hold the lever on the pivot during operation.

3. A switch, as in claim 1, in which the fulcrum for the trip lever is shaped as a relatively sharp inverted V-shaped edge to limit frictional c surface area.

4. A switch comprising a base, a micro-switch assembly including an operating pin, a support plate for the micro-switch assembly, said plate being pivoted at one end with the switch sup ported on the free end of the plate and the operating pin facing in the plane of movement of the plate, a fulcrumed trip lever having a load arm disposed to engage and press the operating pin to actuate the micro-switch and a force arm disposed to receive an external pressure force, a single element on the base to serve as a pivot for the switch support plate and as a fulcrum for the trip lever so the switch support plate and the trip lever will function as the two arms of a tong, and means to bias the work arm of the trip lever away from the switch operating pin and towards a stop serving to define the initial terminal position of the trip lever work arm.

5. A control switch, for use with a riveting machine of the character including two cooper jaws and a deflection plate for measuring separation of the jaws due to operating stresses developed therein, said switch comprising a micro-switch assembly including cooperating contact members and terminals for connections thereto, an actuating element for the contact members, and control means for operating the switch when the free end of the deflection pla moves a predetermined distance relative to the associated jaw of the machine, said control means comprising a trip lever having a short force arm and a long switch operating arm, a fulcrum for supporting and pivoting the lever, a pressure block subject to the movement of one end of the deflection plate and operable as an actuator to engage the short arm of the fulcrumed 'riU lever, a restraining guide for the actuator bl the actuator block in a predete line path of movement against t short arm of the trip lever, a support the switch assembly and the controls therefor, a pivoted plate to support the switch as sly in position with the actuating element t disposed parallel to the path of movement of the end of the long arm of the trip lever, bi spring to bias the switch plate toward the ens. oi the long arm of the trip lever, and a vern iustment screw supported on the tram erative to adjustably position the sw- J against the bias of said spring.

6. A control switch of the character comprising a base plate, a switch 0 having switch mounted thereon, a t1 the switch, a single element serving as a the switch plate and for the trip lever, n biasing the switch and its plate toward the trip lever, means biasing the trip lever away from the switch, means for calibrating the separa tween the switch and the trip lever, and l for locking the switch plate in adjusted. pas

I. A switch, as in claim 6, including a l" and cover plate to enclose the switch, calibrating and locking means ente through the housing and the cover plate mit readjustment of the switch from time to without removing the cover plate.

8. A switch, as in claim 6, inch ating member for the trip lever, g means for the trip lever serving to maintain th trip lever in continous engagement with the 2 .015 3." ating member, and means for maintaining the actuating member in co-planar alignment l the trip lever to assure transfer of the full HOW'AR-D R. FISCEER.

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